Robot hand comprising mechanical link structure

Abstract

The present invention relates to a robot hand that comprises actuators and multi-degree-of-freedom pivot structures embedded in fingers, and is capable of minimizing structural complexity and the number of components while achieving precise interlocking actuation and a high gripping force of a plurality of joints without an external linear movement guiding device by applying a bidirectional cable assembly that accommodates both a link-based underactuation mechanism and compression / extension.

Description

Robot hand including mechanical link structure

[0001] The present invention relates to robot joint actuation technology, and more specifically, to an embedded actuator for precisely acting small multi-degree-of-freedom joints, such as finger joints. In particular, the present invention relates to an embedded actuator for driving multi-degree-of-freedom joints and a robot hand including the same, which includes an oblique axis type actuation unit in which the actuation axis is arranged obliquely with respect to the joint axis, thereby improving structural space efficiency and flexibility in realizing degrees of freedom.

[0002] Robot finger technology is being widely utilized in various industrial fields to perform object grasping and precision manipulation. With the recent rapid advancement of robotic technology, the demand for robotic hands equipped with sophisticated manipulation capabilities similar to human hands is continuously increasing in diverse areas, including medical robots, industrial precision assembly robots, service robots, and rehabilitation assistive devices.

[0003] To meet these requirements, underactuation mechanisms are attracting attention for having a multi-joint structure and capable of driving multiple joints based on a single actuator. Underactuation mechanisms have the advantage of simplifying the structure and reducing the control burden by decreasing the number of actuators relative to the degrees of freedom, as well as enabling gripping characteristics that passively adapt to the shape of external objects.

[0004] Meanwhile, cable or wire-based actuation methods have been widely adopted in conventional robot finger technology. Cable actuation methods have the advantage of reducing the inertia of the robot end-part and enabling agile movements by placing relatively heavy actuators at a distance and transmitting power through lightweight cables. Additionally, they offer the advantage of relatively easy implementation of high-degree-of-freedom structures.

[0005] However, conventional cable or wire-based mechanisms suffer from structural complexity and difficulties in maintenance. Various elements, such as cable path design, tension control mechanisms, pulley placement, and spring configuration, are required in combination; consequently, the assembly process becomes complex, and maintaining and adjusting tension becomes difficult. Furthermore, since cables generally transmit power based on tensile force, they are suitable for unidirectional driving. To implement bidirectional movements, such as the flexion and extension of joints, multiple cables or auxiliary springs corresponding to the number of power transmission directions are required.

[0006] For example, in a structure that uses as many cables as there are power transmission directions, 2n cables and n actuators may be required to drive a joint with n degrees of freedom; in this case, a pretension maintenance device is necessary, and problems with increased friction may occur. Additionally, in a method where individual actuators are connected to each cable, n+1 cables and n+1 actuators are required to drive a joint with n degrees of freedom, which can increase the number of actuators and complicate control. Meanwhile, in a structure that uses auxiliary springs to perform restoration in the opposite direction, n cables, n actuators, and auxiliary springs are required; additional driving force is required to overcome the spring restoring force, which may reduce system efficiency, and the system may become vulnerable to vibration depending on the spring stiffness.

[0007] Furthermore, cable-based mechanisms may experience backlash issues caused by slack, which can lead to reduced gripping precision or errors in response speed. Moreover, the dense arrangement of multiple cables and related components can result in problems such as cable interference, insufficient wiring space, and reduced system reliability.

[0008] On the other hand, even when applying a link-based mechanism, implementing an under-actuation structure may not be easy, or even if under-actuation is implemented, the structure may become complex due to the requirement of multiple links and components. Furthermore, in some conventional link-based structures, it is difficult to secure sufficient gripping force, which may limit practical application.

[0009] Therefore, there is a need for a new robot hand structure that can implement under-actuated characteristics while mitigating structural complexity, and secure bidirectional actuation and tension stability while maintaining the advantages of cable-based actuation.

[0010] The present invention is proposed to solve the problems of the conventional technology described above, and its technical objective is to provide a robot hand structure capable of improving maintenance efficiency by minimizing complex elements such as wire path design, tension control mechanisms, pulleys, and auxiliary springs that cause structural complexity, and replacing them with a simple link-based structure.

[0011] The present invention has the technical objective of solving the problem that it is difficult to implement bidirectional operation in a tension-based unidirectional power transmission structure, and providing a driving structure that can stably implement bending and extension movements of a joint without requiring multiple cables or auxiliary springs corresponding to the number of power transmission directions.

[0012] The technical objective of the present invention is to provide a robot hand structure that enables accurate torque transmission by preventing backlash caused by slack generation, and minimizes gripping force errors and response delays by optimizing the moment arms applied to each joint.

[0013] The present invention has the technical objective of implementing an efficient underactuation mechanism based on the coordinated movement of a single actuator and multiple links, while simultaneously enabling the control of multiple joints with only a minimal link configuration, thereby preventing an increase in the number of parts and structural complexity.

[0014] The present invention has the technical objective of simplifying or eliminating the need for a cable pretension adjustment and maintenance device, mitigating problems such as interference between cables, lack of wiring space, and increased assembly complexity, and solving the problem of requiring an increased number of actuators and complex tension control.

[0015] The present invention has the technical objective of improving system efficiency by reducing the requirement for additional driving force to overcome spring restoring force during driving, and preventing problems such as increased friction and vibration generation.

[0016] The present invention has the technical objective of providing a robot hand structure that eliminates the need for a separate external guiding device, such as a Linear Motion Guide (LM Guide), as in the past, thereby reducing the increase in the number of parts and assembly complexity, enabling the miniaturization and weight reduction of the robot hand, and preventing structural interference, reduced driving efficiency, and vibration caused by alignment problems between the motor output axis and the joint axis.

[0017] The present invention has the technical objective of improving the precision driving limitations that occur in structures where actuators are placed in the forearm, etc., by enabling precise power transmission and control without placing a large actuator directly on the finger or palm.

[0018] The present invention relates to a robot hand that does not include a linear movement guide, comprising: a palm portion; and a finger portion; wherein the palm portion comprises an internal actuator for joint driving configured to be disposed inside the palm portion; the internal actuator for joint driving comprises: a motor configured to provide power to the finger portion; a screw shaft configured to rotate based on the power provided by the motor; a screw nut configured to be rotatably coupled to the screw shaft; and an output link fixedly coupled to the screw nut; wherein the finger portion comprises a universal joint rotatably coupled to the internal actuator for joint driving; wherein the universal joint comprises a movable universal joint coupled to one end of the sliding block to allow the finger portion to have two degrees of freedom of flexion or extension and adduction or abduction; and a supporting universal joint located at the lower end of the internal actuator for joint driving; and wherein the universal joint is configured to restrain the rotation of the screw nut.

[0019] In addition, the above-mentioned support universal joint is configured to fix the position of the built-in actuator for driving the joint while accommodating the rotation of the finger portion.

[0020] In addition, the output link is fixedly coupled to the screw nut and is configured to move only in a straight direction along the axial direction of the screw shaft.

[0021] In addition, the above-mentioned movable universal joint is coupled to the upper end of the output link and configured so that flexion or extension and adduction or abduction movements of the finger portion are performed independently.

[0022] In addition, the built-in actuator for driving the joint is configured to further include a bearing configured to support the screw shaft.

[0023] Additionally, the built-in actuator for driving the joint is configured to further include a bushing configured to restrain the rotation of the screw nut.

[0024] The present invention relates to a robot hand that does not include a linear movement guide, comprising: a palm portion; and a finger portion; wherein the palm portion comprises an internal actuator for joint driving configured to be disposed inside the palm portion; the internal actuator for joint driving comprises: a motor configured to provide power to the finger portion; a screw shaft configured to rotate based on the power provided by the motor; a screw nut configured to be rotatably coupled to the screw shaft; and an output link configured to restrain the rotation of the screw nut; wherein the finger portion comprises a rotational joint rotatably coupled to the internal actuator for joint driving; wherein the rotational joint comprises a power transmission rotational joint coupled to one end of the output link to allow the finger portion to have one degree of freedom of adduction or abduction; and a support rotational joint located at the lower end of the internal actuator for joint driving; and wherein the rotational joint is configured to restrain the rotation of the screw nut.

[0025] In addition, the support rotation joint is configured to fix the position of the built-in actuator for driving the joint while accommodating the rotation of the finger portion.

[0026] In addition, the output link is fixedly coupled to the screw nut and is configured to move only in a straight direction along the axial direction of the screw shaft.

[0027] In addition, the built-in actuator for driving the joint is configured to further include a bearing configured to support the screw shaft.

[0028] The present invention relates to a robot hand that does not include a linear movement guide, comprising: a palm portion; and a finger portion; wherein the palm portion comprises an internal actuator for joint driving configured to be disposed inside the palm portion; the internal actuator for joint driving comprises a fixed portion; and a moving portion; wherein the fixed portion comprises a motor configured to provide power to the finger portion; and the moving portion comprises a screw shaft configured to rotate based on power provided by the motor; a screw nut configured to be rotatably coupled to the screw shaft; and an output link configured to be screw-fastened to the screw nut and rotatably coupled to the finger portion; wherein the finger portion comprises a universal joint rotatably coupled to the end of the output link; wherein the universal joint comprises a movable universal joint rotatably coupled to one end of the output link to allow the finger portion to have two degrees of freedom of flexion or extension and adduction or abduction; and a supporting universal joint located on the screw nut; and wherein the universal joint is configured to restrain the rotation of the screw nut.

[0029] In addition, the lower portion of the output link is configured to correspond to the support universal joint.

[0030] In addition, the screw nut is configured to form a pivot hole in the side wall so as to be fixedly coupled to one end of the output link.

[0031] Additionally, the movable universal joint forms a movable universal joint first protrusion and a movable universal joint second protrusion on each of its sides, and the finger portion comprises a movable universal joint first coupling portion configured such that one end of the finger portion is rotatably coupled to the movable universal joint first protrusion; and a movable universal joint second coupling portion configured such that the other end of the finger portion is rotatably coupled to the movable universal joint second protrusion.

[0032] Additionally, the moving part further includes a fastening pin configured to fasten the movable universal joint so as to be rotatably coupled to the output link; the movable universal joint includes a through hole through which the fastening pin can pass; and the output link includes a fastening hole at one end to receive the fastening pin.

[0033] The present invention relates to a robot hand that does not include a linear movement guide, comprising: a palm portion; and a finger portion; wherein the palm portion comprises an internal actuator for joint driving configured to be disposed inside the palm portion; wherein the internal actuator for joint driving comprises a fixed portion; and a moving portion; wherein the fixed portion comprises a motor configured to provide power to the finger portion; wherein the moving portion comprises a screw shaft configured to rotate based on power provided by the motor; a screw nut configured to be rotatably coupled to the screw shaft; and an output link configured to be screw-fastened to the screw nut and rotatably coupled to the finger portion; wherein the finger portion comprises a rotational joint rotatably coupled to the end of the output link; wherein the rotational joint comprises a power transmission rotational joint coupled to one end of the output link to allow the finger portion to have one degree of freedom of adduction or abduction; and a support rotational joint located on the screw nut; wherein the rotational joint is configured to restrain the rotation of the screw nut.

[0034] In addition, the lower part of the output link is configured to correspond to the support rotation joint.

[0035] In addition, the screw nut is configured to form a pivot hole in the side wall so as to be fixedly coupled to one end of the output link.

[0036] The present invention relates to a robot hand comprising: a palm portion; and a finger portion; wherein the finger portion comprises a metacarpophalangeal (MCP) joint portion; wherein the MCP joint portion comprises a first joint portion configured to enable the finger portion to perform abduction and adduction movements; and a second joint portion configured to enable the finger portion to perform flexion and extension movements; wherein the palm portion comprises an internal actuator for driving the joint configured to be disposed inside the palm portion; wherein the internal actuator for driving the joint comprises a fixed portion; and a moving portion; wherein the fixed portion comprises a motor configured to provide power to the finger portion; and wherein the moving portion comprises a screw shaft configured to rotate based on power provided by the motor; a palm portion coupling frame configured to support the upper and lower ends of the screw shaft and to be coupled to the back of the palm portion; a first connecting link rotatably screw-fastened to the end of the palm portion coupling frame; and a screw nut configured to be rotatably coupled to the screw shaft. An output link configured such that one end is screw-fastened to be fixed to the screw nut and the other end is rotatably coupled to the first connecting link; a second connecting link configured to be rotatably coupled to one end of the first connecting link; and an oblique axis type drive unit configured such that one end is rotatably coupled to one end of the second connecting link and the other end is rotatably coupled to the MCP joint part;The diagonal axis type drive unit is configured to provide two degrees of freedom for the finger part to perform abduction and adduction or flexion and extension movements, and the abduction and adduction movement execution axis of the diagonal axis type drive unit is configured to be positioned at a downward inclination by a predetermined angle with respect to a virtual reference plane formed by the abduction and adduction movement axis of the first joint part and the flexion and extension movement axis of the second joint part.

[0037] The present invention relates to a robot arm assembly comprising: a first actuator; a palm portion; and a finger portion; wherein the finger portion comprises a robot finger configured to perform bending and straightening movements; and the robot finger comprises a joint portion composed of two or more segments of the robot finger; a joint portion configured to be the center of rotation of the joint portion; and a power transmission portion configured to transmit power to the joint portion based on power applied from the first actuator; wherein the joint portion comprises a proximal joint connected to the palm portion; and an intermediate joint connected at the distal end of the proximal joint; and wherein the joint portion comprises an MCP joint which is an axis connected to the palm portion and the proximal joint; and a PIP joint which is an axis connected to the proximal joint and the intermediate joint; and wherein the power transmission portion comprises a power transmission cable configured to transmit a first power applied from the first actuator; and a bell crank configured to transmit a first-second power based on the first power. and a connecting link configured to transmit 1-3 power to the intermediate joint based on the 1-2 power; wherein torque is generated in at least one of the MCP joint and the PIP joint based on the 1 power to cause the robot finger to be underdriven.

[0038] Additionally, the joint portion further includes a distal joint connected at the distal end of the intermediate joint; the joint portion further includes a DIP joint, which is an axis connected to the intermediate joint and the distal joint; the power transmission portion further includes a cross link configured to link the intermediate joint and the distal joint; and based on the first power, torque is generated in at least one of the MCP joint, the PIP joint, and the DIP joint to cause the robot finger to be under-driven.

[0039] In addition, the connecting link includes a connecting link hole configured to prevent mechanical interference with the bell crank.

[0040] In addition, the power transmission cable is configured to transmit the first power based on tension or tensile force.

[0041] Additionally, the robot arm assembly further includes a second actuator; and the power transmission unit further includes an output link configured to transmit a second power applied from the second actuator to the proximal joint; and is configured such that at least one of the proximal joint and the intermediate joint rotates based on the second power to under-drive the robot finger.

[0042] Additionally, the joint portion further includes a distal joint connected at the distal end of the intermediate joint; the joint portion further includes a DIP joint which is an axis connected to the intermediate joint and the distal joint; the power transmission portion further includes a cross link configured to link the intermediate joint and the distal joint; and is configured such that torque is generated in at least one of the MCP joint, the PIP joint, and the DIP joint based on the first power to cause the robot finger to be underdriven, and is configured such that at least one of the proximal joint, the intermediate joint, and the distal joint rotates based on the second power to cause the robot finger to be underdriven.

[0043] The present invention relates to a robot hand comprising: a palm portion; and at least one robot finger; wherein the at least one robot finger is connected to at least one actuator by a cable, the cable having its outer surface surrounded by a tube, the tube having its outer surface surrounded by a spring, and the at least one robot finger is configured to receive power applied to the cable from the at least one actuator.

[0044] In addition, when a tensile force is applied to the cable from the at least one actuator, the spring is configured to prevent deformation of the tube by a reaction force so that the tensile force is transmitted to the at least one robot finger by the cable.

[0045] In addition, when a compressive force is applied to the cable from the at least one actuator, the spring is configured to prevent deformation of the tube by a reaction force so that the compressive force is transmitted to the at least one robot finger by the cable.

[0046] In addition, the above spring is positioned in a compressed state.

[0047] In addition, the above spring is positioned in a tensioned state.

[0048] Additionally, the spring comprises a first spring surrounding the tube; and a second spring surrounding the first spring; wherein the first spring is positioned in a compressed state and the second spring is positioned in a tensioned state.

[0049] In addition, the tube is placed in part or the entire section of the cable, and the spring is placed in part or the entire section of the tube.

[0050] Additionally, the at least one robot finger comprises a segment portion; and a joint portion; wherein the segment portion comprises a proximal segment formed at the base of the robot finger; and the joint portion comprises an MCP joint located at the base of the proximal segment; and the cable is arranged in a curved shape so as not to pass the rotation axis of the MCP joint, the line of action of the power transmitted to the at least one robot finger.

[0051] Additionally, the robot finger further includes a bell crank; and the cable is arranged in a curved shape so that the line of action of the power transmitted to the at least one robot finger does not pass through the axis of rotation of the bell crank.

[0052] In addition, the position of the at least one actuator is adjusted so that the distance from the at least one actuator to the palm portion is maintained at a constant level.

[0053] The present invention relates to a robot hand comprising: a palm portion; and at least one robot finger; wherein the at least one robot finger is connected to at least one actuator by a cable, and the palm portion comprises a cable passage having a difference of less than or equal to the diameter of the cable or a predetermined threshold value.

[0054] The present invention relates to a robot hand comprising: a palm portion; at least one robot finger; and at least one cable guide member disposed between the palm portion and the robot finger; wherein the at least one robot finger is connected to at least one actuator by a cable, and the cable guide member is configured to support the cable to prevent buckling.

[0055] According to the present invention, by including a driving actuator directly embedded inside the finger and a multi-degree-of-freedom pivot structure, complex joint movements can be precisely realized without an external driving device. Accordingly, high-precision joint control similar to human hand movements can be performed without increasing the overall size of the robot hand.

[0056] The present invention can flexibly respond to shaft misalignment and assembly errors by forming a clearance between the coupling part and the flange, or by adopting different coupling structures on the first and second cross sections. Accordingly, the burden on assembly precision is alleviated, and structural interference and abnormal load concentration can be prevented.

[0057] The present invention can stably transmit only the output rotational force while restricting the vertical movement of the motor through a fixed structure, thereby eliminating unnecessary motion and improving driving efficiency. In addition, the utilization of the internal space of the palm is increased, enabling miniaturization and integration.

[0058] The present invention secures the linear movement freedom of the built-in actuator body internally by utilizing a support universal joint, thereby eliminating external guiding structures such as LM guides (Linear Motion Guides) used in conventional technology. Accordingly, additional parts such as rails, sliders, and support brackets become unnecessary, and the effects of reducing the number of parts, simplifying the structure, simplifying the manufacturing process, and reducing costs can be achieved.

[0059] By applying a link-based mechanism, the present invention can reduce structural complexity, such as wire path design, pulley placement, and multiple spring configuration, and facilitate maintenance.

[0060] The present invention overcomes the limitations of tension-based unidirectional transmission structures and enables bidirectional driving of joints by designing the power transmission cable to accommodate both compressive and tensile loads. Accordingly, it is not necessary to require multiple cables or auxiliary springs corresponding to the number of power transmission directions.

[0061] The present invention can suppress backlash by structurally preventing the occurrence of slack, and reduce gripping force errors and improve response speed by optimizing the geometric arrangement of links and the design of moment arms.

[0062] Based on a single actuator and bellcrank design, the present invention can reliably implement an under-actuation mechanism and control multiple joints with only a minimal link configuration. Accordingly, strong gripping force can be secured while reducing the number of parts, and lightweighting and manufacturing simplification can be achieved.

[0063] The present invention can minimize or eliminate complex adjustment devices for maintaining the initial pretension of cables and can alleviate problems such as interference between cables, lack of wiring space, and increased assembly complexity.

[0064] Since the present invention enables the maintenance of stable tension without increasing the number of actuators, it can reduce dependence on complex control algorithms. Accordingly, problems such as cable looseness, loss of synchronization, vibration, and increased friction can be prevented, and system efficiency can be improved.

[0065] Since the present invention does not require additional driving force to overcome spring restoring force, the energy efficiency of the actuator is improved, and the problem of vibration vulnerability caused by the use of a weak spring can be resolved.

[0066] The present invention can provide a robot hand structure capable of simultaneously achieving structural simplification, improved precision controllability, increased driving efficiency, reduced number of parts, and miniaturization.

[0067] FIG. 1a is a drawing for illustrating a first actuator, a second actuator, and a robot finger according to an embodiment of the present invention.

[0068] FIG. 1b is a drawing for explaining the joint and articulation portions of a robot finger according to one embodiment of the present invention.

[0069] FIG. 2 is a conceptual diagram illustrating a high-load gripping motion (HGR) of a robot finger according to one embodiment of the present invention.

[0070] FIG. 3aa is a drawing for explaining the first power (f1), the first-second power (f1-2), and the first-third power (f1-3) in the step (S110) in which the bell crank and the connecting link are linked based on the power transmitted by the power transmission cable according to one embodiment of the present invention.

[0071] FIG. 3ab is a diagram for explaining the component of the first-third power (f1-3) in the step (S110) in which the bell crank and the connecting link are linked based on the power transmitted by the power transmission cable according to one embodiment of the present invention.

[0072] FIG. 3ba is a drawing for explaining the rotation of the DIP joint in the step (S120) in which the intermediate joint and the distal joint rotate according to one embodiment of the present invention.

[0073] FIG. 3bb is a diagram illustrating the rotation of the cross link in the step (S120) in which the intermediate joint and the distal joint rotate according to one embodiment of the present invention.

[0074] FIG. 3bc is a diagram illustrating the rotation of the middle joint and the distal joint during the bending motion of the robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0075] FIG. 4a is a diagram illustrating a link structure for linking the middle joint and the distal joint of a robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0076] FIG. 4b is a diagram illustrating a wire structure for linking the middle joint and the distal joint of a robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0077] FIG. 4c is a diagram illustrating a gear structure for linking the middle joint and the distal joint of a robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0078] FIG. 5a is a diagram illustrating the torque applied to the MCP joint of a robot finger in the step (S130) in which the proximal segment and the intermediate segment rotate according to one embodiment of the present invention.

[0079] FIG. 5b is a diagram illustrating the torque applied to the PIP joint of a robot finger according to an embodiment of the present invention during the step (S130) in which the proximal and intermediate joints rotate.

[0080] FIG. 6 is a conceptual diagram illustrating the fine adjustment motion (FAD) of a robot finger according to one embodiment of the present invention.

[0081] FIG. 7a is a diagram illustrating the step (S210) of rotating the proximal node and the cross link based on the power transmitted by the output link according to one embodiment of the present invention.

[0082] FIG. 7b is a drawing for explaining the step (S220) of rotating the intermediate node and the distal node according to one embodiment of the present invention.

[0083] FIG. 8a is a diagram illustrating the operation steps of the robot finger (100) when the robot finger (100) is in a fully extended state (FES).

[0084] FIG. 8b is a diagram illustrating the operation steps of a robot finger (100) when the middle joint (112) and the distal joint (113) are in a contact limit state.

[0085] FIG. 8c is a diagram illustrating the operation steps of a robot finger (100) when the proximal segment (111), the middle segment (112), and the distal segment (113) are in a contact limit state.

[0086] FIG. 9 is a drawing illustrating a robot finger with a distal segment and a DIP joint omitted according to one embodiment of the present invention.

[0087] FIG. 10a is a drawing for explaining the configuration of a robot hand according to one embodiment of the present invention.

[0088] FIG. 10b is a conceptual diagram illustrating the configuration of a robot finger according to one embodiment of the present invention.

[0089] FIG. 11 is a conceptual diagram illustrating the under-driving of a robot finger based on a power transmission link according to an embodiment of the present invention.

[0090] Figure 12 is a conceptual diagram showing the connection relationships of a robot finger, cable, and actuator in a simplified manner.

[0091] FIG. 13 is a conceptual diagram illustrating the power transmission structure for a robot hand according to a conventional cable drive method.

[0092] FIG. 14 is a conceptual diagram illustrating a push-pull method for a cable according to one embodiment of the present invention.

[0093] Figure 15 is a conceptual diagram illustrating the problems associated with implementing the Push-Pull method with a standard cable.

[0094] FIG. 16 is a conceptual diagram illustrating the configuration of a cable assembly according to one embodiment of the present invention.

[0095] FIG. 17 is a conceptual diagram illustrating the displacement transmission of a cable assembly according to one embodiment of the present invention.

[0096] FIG. 18 is a conceptual diagram illustrating the displacement transmission of a general cable according to a comparative example of the present invention.

[0097] FIG. 19 is a conceptual diagram illustrating a double spring structure according to one embodiment of the present invention.

[0098] FIG. 20 is a drawing for explaining the arrangement of a cable assembly according to one embodiment of the present invention.

[0099] FIG. 21a is a drawing for explaining a cable passage of a palm portion according to one embodiment of the present invention.

[0100] FIG. 21b is a drawing for explaining a cable guide member according to an embodiment of the present invention.

[0101] FIG. 21c is a drawing for explaining the arrangement of a cable guide member according to one embodiment of the present invention.

[0102] FIG. 21d is a side view of a robot hand to illustrate the shape of a cable guide member according to one embodiment of the present invention.

[0103] FIG. 22 is a conceptual diagram illustrating the state of a robot finger according to one embodiment of the present invention.

[0104] FIG. 23a is a conceptual diagram illustrating how to avoid singularities when a tensile force is applied to a cable in the fully extended state (FES) of a robot finger according to one embodiment of the present invention.

[0105] FIG. 23b is a conceptual diagram illustrating that a singularity occurs when a tensile force is applied to a cable in a fully extended state (FES) of a robot finger according to a comparative example of the present invention.

[0106] FIG. 23c is a conceptual diagram illustrating how to avoid singularities when a tensile force is applied to a cable in the fully bent state (FFS) of a robot finger according to one embodiment of the present invention.

[0107] FIG. 23d is a conceptual diagram illustrating that a singularity occurs when a tensile force is applied to a cable in the fully bent state (FFS) of a robot finger according to a comparative example of the present invention.

[0108] FIG. 24aa is a drawing for explaining the finger portion and palm portion of a robot hand according to the present invention.

[0109] FIG. 24ab is a drawing for explaining the back of the hand of the palm portion of a robot hand according to the present invention.

[0110] FIG. 24ac is a drawing for explaining the positions of the first joint driving internal actuator and the second joint driving internal actuator according to the second embodiment of the present invention.

[0111] FIG. 25ba is a drawing to explain the problems of an actuator using a conventional LM guide.

[0112] FIG. 25bb is a drawing for explaining the driving of an actuator that does not use an LM guide according to a first embodiment of the present invention.

[0113] FIG. 25bc is a drawing for explaining the driving of an actuator that does not use an LM guide according to a second embodiment of the present invention.

[0114] FIG. 26 is a drawing illustrating a motor control unit for controlling a motor of an internal actuator for joint driving according to the present invention.

[0115] FIG. 27a is a cross-sectional view illustrating in detail the structure of the coupling part and the bearing part included in the internal actuator for joint driving of the second embodiment of the present invention.

[0116] FIG. 27b is a drawing for illustrating a bearing, a bearing support ring, and a first housing coupling groove of an embedded actuator of a first embodiment of the present invention.

[0117] FIG. 27c is a drawing showing a first cross-section of an internal actuator for joint driving in which a gap is formed between a coupling part and a flange according to a first embodiment of the present invention.

[0118] FIG. 27d is a drawing showing a first cross-section of an embedded actuator for joint driving, in which a gap is formed between the coupling part and the flange according to the first embodiment of the present invention shown in FIG. 27c, so that a ball bearing support ring can be seen.

[0119] FIG. 27e is a drawing showing an example of a commonly used commercial coupling.

[0120] FIG. 28a is a drawing for explaining the driving method of the first joint driving internal actuator and the second joint driving internal actuator according to the first embodiment of the present invention.

[0121] FIG. 28b is a drawing for explaining an embedded actuator support member according to a first embodiment of the present invention.

[0122] FIG. 28c is a drawing for explaining the alignment position of an embedded actuator for joint driving according to a second embodiment of the present invention.

[0123] FIG. 29 is a drawing for explaining an example of driving an embedded actuator according to the angles of abduction / adduction movement and flexion / extension movement of a finger portion according to the first embodiment.

[0124] Specific details of the embodiments are included in the detailed description and drawings.

[0125] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0126] FIG. 1a is a drawing for illustrating a first actuator, a second actuator, and a robot finger according to an embodiment of the present invention.

[0127] As illustrated, the robot arm (1) may include a finger portion (10), a palm portion (20), a wrist portion (30), and a forearm portion (40). Specifically, the finger portion (10) may include at least one robot finger (100) and a thumb (100-t). Additionally, the palm portion (20) may include at least one second actuator (200). Additionally, the wrist portion (30) may include at least one cable assembly (300). Additionally, the forearm portion (40) may include at least one first actuator (400).

[0128] According to one embodiment of the present invention, a robot finger (100) can operate based on power applied from a first actuator (400) or a second actuator (200). Specifically, the robot finger (100) can perform a high-force grab (HGR) operation based on a first power (f1) applied from the first actuator (400). Additionally, the robot finger (100) can perform a fine adjustment (FAD) operation based on a second power (f2) applied from the second actuator (200). That is, the robot finger (100) can achieve backdrivability by separating the high-force grab (HGR) operation and the fine adjustment (FAD) operation. Additionally, the thumb (100-t) can operate based on the first power (f1) applied from the first actuator (400).

[0129] According to one embodiment of the present invention, the first actuator (400) may be positioned on the forearm (40). Accordingly, the weight of the finger portion (10), palm portion (20), and wrist portion (30) is reduced, thereby reducing inertia in movement and improving the reaction speed. Additionally, since the volume and weight of the first actuator (400) can be secured, the robot finger (100) can implement a high-load gripping motion (HGR) with strong gripping force.

[0130] FIG. 1b is a drawing for explaining the joint and articulation portions of a robot finger according to one embodiment of the present invention.

[0131] As illustrated in FIG. 1b, the robot finger (100) may include at least one segment (110) and at least one joint (120). Here, to describe the configuration of the finger (10) in detail, the x-axis (1-a), y-axis (1-b), and z-axis (1-c) are defined.

[0132] According to one embodiment of the present invention, the operation of the robot finger (100) may include abduction and adduction movements. In this case, the abduction and adduction movements of the robot finger (100) may be movements in which the x-axis (1-a) direction is the direction of rotation axis.

[0133] According to one embodiment of the present invention, the operation of the robot finger (100) may include flexion and extension operations. At this time, the flexion and extension operations of the robot finger (100) may be operations in which the y-axis (1-b) direction is the direction of rotation axis.

[0134] According to one embodiment of the present invention, when the robot finger (100) is in a fully extended state (FES) described below, the robot finger (100) can be said to be aligned along the z-axis (1-c) direction. Additionally, the configuration of the robot finger (100) can be divided based on the fully extended state (FES) of the robot finger (100) by classifying the part with the smallest coordinate value on the z-axis (1-c) as the base part, the part with the largest coordinate value on the z-axis (1-c) as the base part, and the part located between the base part and the base part as the middle part.

[0135] According to one embodiment of the present invention, the joint portion (110) may be a segment of the robot finger (100) for performing bending and extension movements of the robot finger (100). Specifically, the joint portion (110) may divide the robot finger (100) into a proximal joint (111), an intermediate joint (112), and a distal joint (113). More specifically, the proximal joint (111) may be a segment formed at the base of the robot finger (100). Additionally, the intermediate joint (112) may be a segment formed at the middle of the robot finger (100). Additionally, the distal joint (113) may be a segment formed at the base of the robot finger (100). Here, the distal joint (113) may be omitted. In this case, the intermediate joint (112) may be a segment formed at the base of the robot finger (100).

[0136] According to one embodiment of the present invention, the joint portion (120) may be a rotational center axis for rotational movement of the segment portion (110). Specifically, the joint portion (120) may include an MCP joint (121), a PIP joint (122), a DIP joint (123), and an external adduction joint (124). More specifically, the MCP joint (121) may be a joint located at the base of the proximal segment (111). Additionally, the PIP joint (122) may be a joint located at the base of the proximal segment (111) and at the base of the middle segment (112). Additionally, the DIP joint (123) may be a joint located at the base of the middle segment (112) and at the base of the distal segment (113). Additionally, the external adduction joint (124) may be a joint located at the base of the proximal segment (111). Here, the DIP joint (123) may be omitted.

[0137] According to the present invention, the Full Extension State (FES) of the robot finger (100) may be a state in which the joint portion (110) does not rotate about the axis of the MCP joint (121), PIP joint (122), and DIP joint (123), and the proximal joint (111), intermediate joint (112), and distal joint (113) are aligned in a line. Additionally, the Intermediate State (IMS) of the bending or extension motion of the robot finger (100) may be a state in which the proximal joint (111) is bent 45 degrees (45 deg) about the axis of the MCP joint (121) relative to the Full Extension State (FES) of the robot finger (100). Additionally, the intermediate state (IMS) of the bending or straightening motion of the robot finger (100) may be a state in which the intermediate joint (112) is bent 45 degrees (45 deg) with respect to the full flexion state (FFS) of the robot finger (100) and the PIP joint (122) as an axis.

[0138] According to the present invention, the fully bent state (FFS) of the robot finger (100) may be a state in which the proximal segment (111) is bent 90 degrees (90 deg) with respect to the fully extended state (FES) of the robot finger (100) and the MCP joint (121) as the axis. Additionally, the fully bent state (FFS) of the robot finger (100) may be a state in which the middle segment (112) is bent 110 degrees (110 deg) with respect to the fully extended state (FES) of the robot finger (100) and the PIP joint (122) as the axis.

[0139] FIG. 2 is a conceptual diagram illustrating a high-load gripping motion (HGR) of a robot finger according to one embodiment of the present invention.

[0140] The power transmission unit (130) of the present invention can perform bending or straightening movements of the robot finger (100). Specifically, the power transmission unit (130) may include a power transmission cable (131), a bell crank (132), a connecting link (133), a cross link (134), and an output link (135).

[0141] According to one embodiment of the present invention, the power transmission unit (130) can transmit the first power (f1) received from the first actuator (400) to the joint unit (110). Specifically, the joint unit (110) can receive power through the interlocking of the power transmission cable (131), the Velcrok (132), the connecting link (133), and the cross link (134). Here, the first power (f1) may refer to the force applied to the power transmission cable (131) based on the first actuator (400) from power generated outside the robot finger (100). Additionally, the first power (f1) may be expressed as a vector having magnitude and direction.

[0142] According to one embodiment of the present invention, the power transmission unit (130) can transmit the second power (f2) received from the second actuator (200) of FIG. 6, which will be described later, to the joint unit (110). Specifically, the joint unit (110) can receive power through the interlocking of the output link (135) and the cross link (134). Here, the second power (f2) may refer to the force applied to the output link (135) based on the second actuator (200) from power generated outside the robot finger (100). Additionally, the second power (f2) may be expressed as a vector having magnitude and direction.

[0143] According to one embodiment of the present invention, a power transmission cable (131) can transmit a first power (f1) to a robot finger (100). Specifically, the power transmission cable (131) can transmit the first power (f1) applied from a first actuator (400) to a bell crank (132).

[0144] According to one embodiment of the present invention, the power transmission cable (131) can form tension and tensile force while maintaining a curved shape. Specifically, the power transmission cable (131) can be wrapped with a tube (not shown) and a spring (not shown). Here, the power transmission cable (131) is supported by the tube and the spring, and can form tension while maintaining a bent state. Accordingly, the direction of the first power (f1) may be the tangential direction of the power transmission cable (131) at the point where the power transmission cable (131) is connected to the Velcrok (132). In addition, the power transmission cable (131) is designed to have a thick diameter so that it can form not only tension but also tensile force. That is, even if the power transmission cable (131) is described as forming tension to explain the bending motion process of the robot finger (100) below, it is obvious that the straightening motion process of the robot finger (100) based on the tensile force of the power transmission cable (131) can be understood. Additionally, the power transmission cable (131) may be omitted, in which case the first power (f1) may be transmitted to the bell crank (132) based on a gear or link structure.

[0145] According to the present invention, the bell crank (132) can transmit a first power (f1) received from a power transmission cable (131) to a connecting link (133). Specifically, the bell crank (132) may include a bell crank first pivot (132-1), a bell crank second pivot (132-2), and a bell crank rotation pivot (132-r) of FIG. 5A. Here, the first pivot refers to a pivot where the bell crank (132) receives the first power (f1). Additionally, the second pivot refers to a pivot where the bell crank (132) and the connecting link (132) are connected. Additionally, the bell crank rotation pivot (132-r) refers to a pivot that becomes the center of rotation when the bell crank (132) rotates. More specifically, the first pivot (132-1) of the bellcrank can receive the first power (f1) from the power transmission cable (131). Subsequently, the bellcrank rotation pivot (132-r) can receive torque based on the first power (f1) and rotate around the z-axis (1-c). Subsequently, the second pivot (132-2) of the bellcrank can transmit the first-second power (f1-2) to the connecting link (133, not shown) based on the rotation of the bellcrank rotation pivot (132-r). At this time, the direction of the first-second power (f1-2) may be different from the direction of the first power (f1).

[0146] According to the present invention, the connecting link (133) can transmit the first-second power (f1-2) of FIG. 3aa to the intermediate joint (112). The connecting link (133) can be designed to enable stable operation without shaking in the z-axis (1-c) direction when the robot finger (100) performs a bending or straightening motion. Specifically, the Velcrok (132) can be located on the same z-axis (1-c) coordinate as the connecting link (133). Accordingly, the Velcrok (132) and the connecting link (133) can be aligned on the x-axis (1-a). That is, the Velcrok (132) can transmit the first-second power (f1-2) to the connecting link (133) only in the x-axis (1-a) direction.

[0147] According to the present invention, the cross link (134) may include a cross link first pivot (134-1) of FIG. 7a and a cross link second pivot (134-2) of FIG. 7b. Here, the cross link first pivot (134-1) refers to a pivot to which the cross link (134) and the proximal node (111) are connected. Additionally, the cross link second pivot (134-2) refers to a pivot to which the cross link (134) and the distal node (113) are connected.

[0148] According to one embodiment of the present invention, the output link (135) can transmit a second power (f2) to the robot finger (100). Specifically, the output link (135) can transmit the second power (f2) applied from the second actuator (200) to the proximal joint (111).

[0149] According to one embodiment of the present invention, the robot finger (100) can perform bending and straightening movements. Specifically, the robot finger (100) can perform a high-load gripping movement (HGR) and a fine adjustment movement (FAD) in relation to the bending and straightening movements.

[0150] FIG. 2(a) is a conceptual diagram of a robot finger (100) in a fully extended state (FES). FIG. 2(b) is a conceptual diagram of a robot finger (100) in an intermediate state (IMS). FIG. 2(c) is a conceptual diagram of a robot finger (100) in a fully bent state (FFS).

[0151] In the high-load gripping motion (HGR) of the robot finger (100), the joint (110) can operate based on the operation of the power transmission unit (130). Specifically, the distal joint (113) and the middle joint (112) can operate based on the operation of the cross link (134). The operation of the middle joint (112) and the distal joint (113) is described in detail in the description of the step (S120) in which the middle joint and the distal joint rotate. Additionally, the proximal joint (111) and the middle joint (112) can operate based on the operation of the bell crank (132) and the connecting link (133). The operation of the proximal joint (111) and the middle joint (112) is described in detail in the step (S130) in which the proximal joint and the middle joint rotate.

[0152] According to one embodiment of the present invention, the step (S100) of a robot finger performing a high-load gripping operation may include a step (S110) in which a bell crank and a connecting link interlock based on power transmitted by a power transmission cable, a step (S120) in which an intermediate joint and a distal joint rotate, and a step (S130) in which a proximal joint and an intermediate joint rotate. Additionally, the high-load gripping operation (HGR) of the robot finger (100) may be implemented as an underactuation mechanism. Specifically, the high-load gripping operation (HGR) may be implemented based solely on a first power (f1). More specifically, the high-load gripping operation (HGR) may be underactuation as torque is generated in at least one of the MCP joint (121), PIP joint (122), and DIP joint (123) based on the first power (f1).

[0153] FIG. 3aa is a drawing for explaining the first power (f1), the first-second power (f1-2), and the first-third power (f1-3) in the step (S110) in which the bell crank and the connecting link are linked based on the power transmitted by the power transmission cable according to one embodiment of the present invention.

[0154] FIG. 3ab is a diagram for explaining the component of the first-third power (f1-3) in the step (S110) in which the bell crank and the connecting link are linked based on the power transmitted by the power transmission cable according to one embodiment of the present invention.

[0155] According to one embodiment of the present invention, the step (S110) in which the bell crank and the connecting link interlock based on the power transmitted by the power transmission cable may be a step in which the power transmission unit (130) transmits power to the joint unit (110) and the joint unit (120). Specifically, the power transmission cable (131) may transmit the first power (f1) received from the first actuator (400) to the bell crank (132). Additionally, the bell crank (132) may transmit the first-second power (f1-2) to the connecting link (133) based on the first power (f1). Additionally, the connecting link (133) may transmit the first-third power (f1-3) to the intermediate joint (112) based on the first-second power (f1-2).

[0156] As illustrated in FIG. 3aa, the first power (f1) may be a force transmitted by the power transmission cable (131) to the bell crank (132). The direction of the first power (f1) may be tangential to the power transmission cable (131) at the point where the power transmission cable (131) is connected to the bell crank (132). Additionally, the first-2 power (f1-2) may include a first-2a component force (f1-2a) and a first-2b component force (f1-2b). Here, the first-2a component force (f1-2a) refers to a force that is a component of the first-2 power (f1-2) in a direction perpendicular to the connecting link centerline (133-centerline), which is a straight line connecting the connecting link first pivot (133-1) and the connecting link second pivot (133-2). Additionally, the first-2b component force (f1-2b) refers to a force that is a component of the first-2 power (f1-2) in a direction parallel to the connecting link centerline (133-centerline). Also, the magnitude of the first-3 power (f1-3) may be the same as the magnitude of the first-2b component force (f1-2b).

[0157] As illustrated in FIG. 3ab, the first-3 power (f1-3) may include a first-3a component (f1-3a) and a first-3b component (f1-3b). Here, the first-3a component (f1-3a) refers to a force that is a component of the first-3 power (f1-3) in a direction parallel to the PIP centerline (122-133-centerline), which is a straight line connecting the connecting link second pivot (133-2) and the PIP joint (122). Additionally, the first-3b component (f1-3b) refers to a force that is a component of the first-3 power (f1-3) in a direction perpendicular to the PIP centerline (122-133-centerline).

[0158] According to one embodiment of the present invention, the proximal segment (111) may be able to rotate around the MCP joint (121) based on the frictional force between the bellcrank rotation pivot (132-r) and the proximal segment (111). At this time, the magnitude of the frictional force between the bellcrank rotation pivot (132-r) and the proximal segment (111) may be adjusted according to the purpose of use of the robot finger (100).

[0159] S120

[0160] FIG. 3ba is a drawing for explaining the rotation of the DIP joint in the step (S120) in which the intermediate joint and the distal joint rotate according to one embodiment of the present invention.

[0161] FIG. 3bb is a diagram illustrating the rotation of the cross link in the step (S120) in which the intermediate joint and the distal joint rotate according to one embodiment of the present invention.

[0162] FIG. 3bc is a diagram illustrating the rotation of the middle joint and the distal joint during the bending motion of the robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0163] According to one embodiment of the present invention, the step (S120) of rotating the intermediate joint and the distal joint may be a step of applying torque to the PIP joint (122) and the DIP joint (123). Specifically, the torque applied to the PIP joint (122) and the DIP joint (123) may be described as orbital movement (OM) of the DIP joint (123) and the cross link second pivot (134-2).

[0164] As illustrated in FIG. 3ba, the DIP joint (123) can rotate (123-OM) based on the first-third power (f1-3). Specifically, the PIP joint (122) can generate a torque (122-torque) based on the first-third component force (f1-3b). Additionally, the DIP joint (123) can rotate (123-OM) around the PIP joint (122) based on the torque (122-torque) of the PIP joint.

[0165] As illustrated in FIG. 3bb, the cross link second pivot (134-2) can rotate (134-2-OM) based on the rotation (123-OM) of the DIP joint. Specifically, the distal segment (113) can rotate (130-OM) around the PIP joint (122) based on the rotation (123-OM) of the DIP joint. The cross link second pivot (134-2) axially connected to the distal segment (113) can rotate (134-2-OM) around the cross link first pivot (134-1). Here, the torque (123-torque) applied to the DIP joint can be generated based on the rotation (134-2-OM) of the second cross link pivot.

[0166] As illustrated in FIG. 3bc, the intermediate joint (112) and the distal joint (113) can rotate based on the torque (122-torque) applied to the PIP joint and the torque (123-torque) applied to the DIP joint. Specifically, as previously described, the torque (122-torque) applied to the PIP joint can be generated based on the first-3b component force (f1-3b). Additionally, the torque (123-torque) applied to the DIP joint can be generated based on the rotation (134-2-OM) of the second cross link pivot. More specifically, the torque (123-torque) applied to the DIP joint can be generated based on the first-4b component force (f1-4b). Here, the first-4b component force (f1-4b) refers to the force that is perpendicular to the force of the second cross-link pivot rotating (134-2-OM) with respect to the straight line (123-134-centerline) connecting the DIP joint (123) and the second cross-link pivot (134-2).

[0167] FIG. 4a is a diagram illustrating a link structure for linking the middle joint and the distal joint of a robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0168] FIG. 4b is a diagram illustrating a wire structure for linking the middle joint and the distal joint of a robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0169] FIG. 4c is a diagram illustrating a gear structure for linking the middle joint and the distal joint of a robot finger in the step (S120) in which the middle joint and the distal joint rotate according to one embodiment of the present invention.

[0170] According to one embodiment of the present invention, the step (S120) of rotating the intermediate joint and the distal joint can be implemented not only with a link structure but also with a wire structure and a gear structure. Additionally, the torque (122-torque) applied to the PIP joint and the torque (123-torque) applied to the DIP joint can have their size ratios pre-designed.

[0171] As shown in FIG. 4a, the step (S120) of rotating the middle and distal nodes can be implemented with a four-bar link structure.

[0172] As illustrated in FIG. 4b, the step (S120) of rotating the intermediate joint and the distal joint can be implemented as a wire structure. Specifically, the wire of the robot finger (100) may include a first wire (6b-1) and a second wire (6b-2). Additionally, the sum of the lengths of the first wire (6b-1) and the second wire (6b-2) may be maintained equal during the bending motion of the robot finger (100).

[0173] As illustrated in FIG. 4c, the step (S120) of rotating the intermediate joint and the distal joint can be implemented as a gear structure. Specifically, the gear of the robot finger (100) includes a first gear (6c-1) and a second gear (6b-2) to ensure motion stability of the three joints.

[0174] FIG. 5a is a diagram illustrating the torque applied to the MCP joint of a robot finger in the step (S130) in which the proximal segment and the intermediate segment rotate according to one embodiment of the present invention.

[0175] FIG. 5b is a diagram illustrating the torque applied to the PIP joint of a robot finger according to an embodiment of the present invention during the step (S130) in which the proximal and intermediate joints rotate.

[0176] According to one embodiment of the present invention, the step (S130) of rotating the proximal segment and the intermediate segment may be a step of applying torque to the MCP joint (121) and the PIP joint (122). Additionally, the magnitude of the torque applied to the MCP joint (121) and the PIP joint (122) may be designed differently based on the structure of the bell crank (132) and the connecting link (133). Before describing the torque applied to the MCP joint (121) and the PIP joint (122), the following terms are defined to describe the high-load gripping motion (HGR) of the robot finger (100).

[0177] The first moment arm (m1) refers to the distance between the first power source (f1) and the MCP joint (121). Additionally, the second moment arm (m2) refers to the distance between the first power source (f1) and the bellcrank rotation pivot (132-r). Additionally, the third moment arm (m3) refers to the distance between the connecting link centerline (133-centerline) and the bellcrank rotation pivot (132-r). Additionally, the fourth moment arm (m4) refers to the distance between the connecting link centerline (133-centerline) and the PIP joint (122). Additionally, the range of motion state refers to a state in which one or more joints or links of the robot finger (100) have reached the end of the mechanical range of motion designed for the robot finger (100), making further movement impossible. Additionally, the contact limit state refers to a state in which one or more joints or links of the robot finger (100) are mechanically unable to perform further movement based on contact between the robot finger (100) and an external object.

[0178] As illustrated in FIG. 5a, the torque (121-torque) applied to the MCP joint can be generated based on the first moment arm (m1) and the first power (f1). Specifically, when the bell crank (132) is in a motion limit state or a contact limit state, the magnitude of the torque (121-torque) applied to the MCP joint can be calculated by [Equation 1].

[0179] [Equation 1]

[0180]

[0181] According to one embodiment of the present invention, the structure of the Velcrok (132) can be designed based on [Equation 1]. Specifically, the structure of the Velcrok (132) can be designed to avoid the singularity described below, that is, so that the first moment arm (m1) does not become zero. In addition, the structure of the Velcrok (132) can be designed to have the linearity described below, that is, so that the size of the first moment arm (m1) is the same over the entire range of motion of the robot finger (100). More specifically, in order to have singularity avoidance and linearity based on the fully extended state (FES) of the robot finger (100), the bell crank (132) can be designed based on the position of the bell crank rotation pivot (132-r) on the x-axis (1-a) and the rotation radius of the bell crank first pivot (132-1), that is, the distance between the bell crank first pivot (132-1) and the bell crank rotation pivot (132-r).

[0182] As illustrated in FIG. 5b, the torque (122-torque) applied to the PIP joint can be generated based on the second moment arm (m2), the third moment arm (m3), and the fourth moment arm (m4). Specifically, the magnitude of the torque (122-torque) applied to the PIP joint can be calculated by [Equation 2].

[0183] [Equation 2]

[0184]

[0185] According to one embodiment of the present invention, the structure of the bell rank (132) and the connecting link (133) can be designed based on [Equation 2]. Specifically, the structure of the bell rank (132) and the connecting link (133) can be designed so that the magnitude of the torque (122-torque) applied to the PIP joint has a certain ratio to the magnitude of the torque (121-torque) applied to the MCP joint. For example, the structure of the bell rank (132) and the connecting link (133) can be designed so that the magnitude of the torque (122-torque) applied to the PIP joint and the magnitude of the torque (121-torque) applied to the MCP joint have a ratio of 1 to 2. More specifically, the bell crank (132) and the connecting link (133) can be designed based on the distance between the connecting link first pivot (133-1) and the connecting link second pivot (133-2), the position of the connecting link second pivot (133-2) on the x-axis (1-a) and z-axis (1-c) based on the fully extended state (FES) of the robot finger (100), and the radius of rotation of the bell crank second pivot (132-2), i.e., the distance between the bell crank second pivot (132-2) and the bell crank rotation pivot (132-r).

[0186] FIG. 6 is a conceptual diagram illustrating a fine adjustment motion (FAD) of a robot finger according to an embodiment of the present invention. Specifically, FIG. 6 (a) is a conceptual diagram of a robot finger (100) when performing a motion in which the fingertip moves away based on a second power source in an intermediate state (IMS). Also, FIG. 6 (b) is a conceptual diagram of a robot finger (100) when performing a motion in which the fingertip moves closer based on a second power source in an intermediate state (IMS).

[0187] According to one embodiment of the present invention, in the fine adjustment operation (FAD) of a robot finger (100), the joint portion (110) may operate based on the operation of the power transmission portion (130). Specifically, the proximal joint (111) may operate based on the second power (f2) transmission of the output link (135). The operation of the proximal joint (111) is described in detail in the step (S210) in which the proximal joint and the cross link rotate based on the power transmitted by the output link. Additionally, the distal joint (113) and the middle joint (112) may operate based on the rotation of the cross link (134). The operation of the middle joint (112) and the distal joint (113) is described in detail in the description of the step (S220) in which the middle joint and the distal joint rotate.

[0188] As illustrated in FIG. 6(a), the robot finger (100) can perform a movement in which the fingertip (100-tip) moves away based on the second power (f2). Specifically, by restricting the movement of the bell crank (132) and the connecting link (133), and when the output link (135) transmits the second power (f2) to the proximal joint (111) in a positive direction relative to the z-axis (1-c), the fingertip (100-tip) can move in a positive direction relative to the x-axis (1-a) and a positive direction relative to the z-axis (1-c).

[0189] As illustrated in FIG. 6(b), the robot finger (100) can perform a movement in which the fingertip (100-tip) moves closer based on the second power (f2). Specifically, by restricting the movement of the bell crank (132) and the connecting link (133), and when the output link (135) transmits the second power (f2) to the proximal joint (111) in the negative direction relative to the z-axis (1-c), the fingertip (100-tip) can move in the negative direction relative to the x-axis (1-a) and the negative direction relative to the z-axis (1-c).

[0190] According to one embodiment of the present invention, the step (S200) of the robot finger performing a fine adjustment operation may include the step (S210) of rotating the proximal joint and the cross link based on the power transmitted by the output link, and the step (S220) of rotating the intermediate joint and the distal joint. Additionally, the fine adjustment operation (FAD) of the robot finger (100) may be implemented as an underactuation mechanism. Specifically, the fine adjustment operation (FAD) of the robot finger (100) may be implemented based solely on the second power (f2).

[0191] FIG. 7a is a diagram illustrating the step (S210) of rotating the proximal node and the cross link based on the power transmitted by the output link according to one embodiment of the present invention.

[0192] As described, the step (S210) in which the proximal segment and the cross link rotate based on the power transmitted by the output link may be a step in which the proximal segment (111) and the cross link (134) rotate based on the second power (f2) transmitted by the output link (135). Specifically, the proximal segment (111) may rotate (111-rotate) around the MCP joint (121) based on the second power (f2). Subsequently, the cross link (134) may rotate (134-rotate) around the cross link first pivot (134-1).

[0193] FIG. 7b is a drawing for explaining the step (S220) of rotating the intermediate node and the distal node according to one embodiment of the present invention.

[0194] As described, the step (S220) in which the intermediate node and the distal node rotate is a step in which the intermediate node (112) and the distal node (113) rotate based on the cross link rotation (134-rotate) of the step (S210) in which the proximal node and the cross link rotate based on the power transmitted by the output link. Specifically, the cross link second pivot (134-2) may rotate (134-2-OM) based on the cross link rotation (134-rotate). Accordingly, the distal node (113) may rotate (113-rotate) around the DIP joint (123). Additionally, the intermediate node (112) may rotate (112-rotate) around the PIP joint (122).

[0195] FIG. 8a is a diagram illustrating the operation steps of the robot finger (100) when the robot finger (100) is in a fully extended state (FES).

[0196] FIG. 8b is a diagram illustrating the operation steps of a robot finger (100) when the middle joint (112) and the distal joint (113) are in a contact limit state.

[0197] FIG. 8c is a diagram illustrating the operation steps of a robot finger (100) when the proximal segment (111), the middle segment (112), and the distal segment (113) are in a contact limit state.

[0198] The operation steps of the robot finger (100) may include a step (S110) in which the bell crank and connecting link interlock based on the power transmitted by the power transmission cable, a step (S120) in which the middle joint and distal joint rotate, and a step (S130) in which the proximal joint and middle joint rotate, and may be described by whether the joint portion (110) rotates.

[0199] As illustrated in FIG. 8a, when the robot finger (100) is in a fully extended state (FES), in step (S110) where the bellcrank and connecting link interlock based on the power transmitted by the power transmission cable, the middle segment (112) can receive the first-third power (f1-3). Subsequently, the middle segment (112) and the distal segment (113) can rotate based on the first-third component (f1-3b) and the first-fourth component (f1-4b), respectively. In contrast, the proximal segment (111) may not rotate based on the fact that the middle segment (112) and the distal segment (113) are not in a motion limit state or a contact limit state. That is, the step (S130) in which the proximal segment and the middle segment rotate can be omitted.

[0200] As illustrated in FIG. 8b, when the middle node (112) and the distal node (113) are in contact with an object (OB) and are in a contact limit state, in the step (S110) where the bell crank and the connecting link interlock based on the power transmitted by the power transmission cable, the middle node (112) can receive the first-3b component force (f1-3b). However, since the middle node (112) and the distal node (113) are in a contact limit state, they may not rotate based on the step (S120) where the middle node and the distal node rotate. At this time, since torque is applied to the PIP joint (122) and the DIP joint (123), the middle node (112) or the distal node (113) can maintain a contact state with the object (OB). Additionally, since the middle node (112) or the distal node (113) is in a contact limit state, in the step (S130) where the proximal node and the middle node rotate, the proximal node (111) and the middle node (112) can rotate.

[0201] As illustrated in FIG. 8c, when the proximal segment (111), middle segment (112), and distal segment (113) are in contact with the object (OB) and are in a contact limit state, in the step (S110) where the bell crank and connecting link interlock based on the power transmitted by the power transmission cable, the middle segment (112) can receive the first-third power (f1-3). However, since the middle segment (112) and distal segment (113) are in a contact limit state, they may not rotate based on the step (S120) where the middle segment and distal segment rotate. At this time, since torque is applied to the PIP joint (122) and DIP joint (123), the middle segment (112) or distal segment (113) can maintain a contact state with the object (OB). Additionally, since the middle joint (112) or the distal joint (113) is in a contact limit state, the proximal joint (111) and the middle joint (112) may not rotate during the step (S130) in which the proximal joint and the middle joint rotate. At this time, torque is applied to the MCP joint (121) and the DIP joint (122), so the proximal joint (111) or the middle joint (112) can maintain a contact state with the object (OB).

[0202] According to one embodiment of the present invention, a robot finger (100) can perform operations with underactuation, adapt to various situations, and perform grasping operations on objects (OB) of various sizes and shapes. Specifically, the robot finger (100) can independently perform a high-load grasping operation (HGR) and a fine adjustment operation (FAD). Accordingly, the robot finger (100) can flexibly respond to various situations and objects (OB) by combining the high-load grasping operation (HGR) and the fine adjustment operation (FAD). For example, in a situation where an object (OB), such as a bottle cap or a screw, needs to be turned, the robot finger (100) can grasp the object (OB) with a high-load grasping operation (HGR) and turn it by manipulating the fingertip (100-tip) based on the fine adjustment operation (FAD). Additionally, the robot finger (100) can independently control the joint (110) by combining a heavy gripping motion (HGR) and a fine adjustment motion (FAD) according to the size or shape of the object (OB).

[0203] FIG. 9 is a drawing illustrating a robot finger with a distal segment and a DIP joint omitted according to one embodiment of the present invention.

[0204] As illustrated, the distal segment (113), DIP joint (123), and cross link (134) may be omitted. Accordingly, the step (S120) in which the middle segment and distal segment rotate may be omitted. Additionally, in the step (S130) in which the proximal segment and middle segment rotate, even if the bell rank (132) is not in a motion limit state or a contact limit state, the magnitude of the torque (121-torque) applied to the MCP joint may be calculated based on [Equation 1].

[0205] FIG. 10a is a drawing for explaining the configuration of a robot hand according to one embodiment of the present invention.

[0206] As illustrated, the robot hand (2) may include finger portions (10) and palm portions (20). Specifically, the finger portions (10) may be composed of five fingers to mimic the structure of a human hand. Additionally, the finger portions (10) may perform movements by receiving power applied from actuators through a cable (not shown). More specifically, the thumb (11) may receive power applied from two actuators (a1-1 and a1-2), and the remaining fingers (12, 13, 14, and 15) excluding the thumb (11) may receive power from corresponding actuators (a2, a3, a4, and a5) through a power transmission cable (131) to perform movements such as flexion, extension, abduction, and adduction.

[0207] FIG. 10b is a conceptual diagram illustrating the configuration of a robot finger according to one embodiment of the present invention.

[0208] As described above, the finger portion (10) may include a segment portion (110), a joint portion (120), and a power transmission portion (130). The segment portion (110) of the present invention may be a segment of the finger portion (10). Specifically, the segment portion (110) may be composed of a proximal segment (111), an intermediate segment (112), and a distal segment (113) of the finger portion (10). More specifically, the proximal segment (111) may be a segment formed at the base of the finger portion (10). Additionally, the intermediate segment (112) may be a segment formed at the middle of the finger portion (10). Additionally, the distal segment (113) may be a segment formed at the distal end of the finger portion (10). Here, the distal segment (113) may be omitted. In this case, the intermediate segment (112) may be a segment formed at the distal end of the finger portion (10).

[0209] According to one embodiment of the present invention, the joint portion (120) may be a rotational center axis for rotational movement of the segment portion (110). Specifically, the joint portion (120) may include an MCP joint (121, Metacarpophalangeal Joint), a PIP joint (122, Proximal Interphalangeal Joint), and a DIP joint (123, Distal Interphalangeal Joint). More specifically, the MCP joint (121) may be a joint located at the base of the proximal segment (111). Additionally, the PIP joint (122) may be a joint located at the distal end of the proximal segment (111) and at the base of the intermediate segment (112). Additionally, the DIP joint (123) may be a joint located at the distal end of the intermediate segment (112) and at the base of the distal segment (113). Here, the DIP joint (123) may be omitted.

[0210] FIG. 11 is a conceptual diagram illustrating the under-driving of a robot finger based on a power transmission link according to an embodiment of the present invention.

[0211] As illustrated, the power transmission unit (130) may include a bell rank (132), a connecting link (133), and a cross link (134). At this time, power applied from the actuator to the power transmission cable (131) is sequentially transmitted through the bell rank (132) and the connecting link (133), so that the proximal segment (111), the middle segment (112), and the distal segment (113) can rotate around the MCP joint (121), the PIP joint (122), and the DIP joint (123), respectively. Specifically, the bell rank (132) rotates based on the power applied to the power transmission cable (131), and torque may be generated at the MCP joint (121). Subsequently, the connecting link (133) coupled with the bell rank (132) can transmit power to the middle segment (112) to cause it to rotate around the PIP joint (122). Additionally, the cross link (134) can link the middle joint (112) and the distal joint (113). That is, power based on a single actuator is distributed to multiple joints (121, 122, and 123), and since multiple joints (111, 112, and 113) rotate, the finger portion (10) can perform a bending motion with underactuation.

[0212] Figure 12 is a conceptual diagram showing the connection relationships of a robot finger, cable, and actuator in a simplified manner.

[0213] As described, the robot finger can be represented as having one degree of freedom, consisting of one joint and one segment. At this time, when the power transmission cable (131) transmits power applied from the actuator to the joint, the segment can rotate around the joint.

[0214] FIG. 13 is a conceptual diagram illustrating a power transmission structure for a robot hand according to a conventional cable drive method. Specifically, FIG. 13 (a) is to explain a method using as many cables as there are power transmission directions, FIG. 13 (b) is to explain a method connecting an actuator to each cable, and FIG. 13 (c) is to explain a method using an auxiliary spring.

[0215] FIG. 14 is a conceptual diagram illustrating a push-pull method for a cable according to one embodiment of the present invention.

[0216] The following describes conventional cable driving methods, such as a method using cables equal to the number of power transmission directions, a method connecting an actuator to each cable, a method using an auxiliary spring, and the Push-Pull method, which is the cable driving method of the present invention.

[0217] A method of using cables corresponding to the number of power transmission directions according to one embodiment of the present invention is a method of using 2n cables and n actuators to drive a joint of n degrees of freedom. Specifically, as shown in FIG. 13 (a), two cables (cable-1 and cable-2) that rotate the joint in opposite directions are used for a joint of 1 degree of freedom. In addition, the actuator can selectively apply power to one of the two cables (cable-1 and cable-2).

[0218] In this case, using cables for each power transmission direction allows the actuator control method to be as simple as a direct connection structure. However, there is a problem in that a tension adjustment device is required to maintain initial pretension in the cables. Additionally, this initial pretension causes the problem of increasing the frictional resistance of the cables.

[0219] A method of connecting actuators to each cable according to one embodiment of the present invention is a method of using n+1 cables and n+1 actuators to drive a joint of n degrees of freedom. In this case, each cable is connected to a different actuator. Specifically, as shown in FIG. 4(b), two cables (cable-1 and cable-2) that rotate the joint in opposite directions are used for a joint of 1 degree of freedom. In addition, the two cables (cable-1 and cable-2) each receive power from different actuators (actuator-1 and actuator-2).

[0220] In this case, the method of connecting an actuator to each cable may require fewer cables as the joint's degrees of freedom increase compared to the method using cables equal to the number of power transmission directions. However, this increases the number of required actuators and presents the problem that the actuators must control the cables in a complex manner to maintain their initial pretension. Additionally, there is a risk of the cables losing synchronization if the actuator control is inaccurate.

[0221] A method of using auxiliary springs according to one embodiment of the present invention is a method of using n cables, auxiliary springs, and n actuators to drive a joint of n degrees of freedom. Specifically, as shown in FIG. 13 (c), a cable that rotates the joint in one direction and a spring that restores it in the opposite direction are used for a joint of 1 degree of freedom.

[0222] In this case, the method using auxiliary springs may require fewer cables. However, since the cable must be stretched while overcoming the spring's restoring force, there is a problem of reduced driving efficiency and increased friction. Therefore, weaker springs are used, but in this case, there is a problem of vibration occurring when the arm moves. Additionally, when using weak springs, the spring's restoring force becomes small, and consequently, there is a problem of not being able to generate a large force in the extending direction.

[0223] The Push-Pull method of the present invention may be a method that uses n cables and n actuators to drive a joint of n degrees of freedom. In this case, the n cables may be driven independently by different actuators. Additionally, the actuators may apply power by pushing or pulling the cables. Specifically, as shown in FIG. 5, one cable and a linear actuator may be used for a joint of one degree of freedom. In this case, since the Push-Pull method can rotate the joint in both directions with only one cable, the number of cables required for the Push-Pull method may be small.

[0224] Figure 15 is a conceptual diagram illustrating the problems associated with implementing the Push-Pull method with a standard cable.

[0225] As described above, when a compressive force is applied to a general cable from a linear actuator in a push-pull method, the general cable buckles. At this time, since the critical buckling load of the general cable is significantly smaller than the power required to drive the finger portion (10), there is a problem that the general cable cannot transmit the compressive force to the finger portion (10). As an embodiment of the present invention to solve this problem, a cable assembly (300) is described below.

[0226] FIG. 16 is a conceptual diagram illustrating the configuration of a cable assembly according to one embodiment of the present invention.

[0227] As described, the cable assembly (300) may have a structure such as a conduit to implement a push-pull method. Specifically, the cable assembly (300) may include a cable (310), a tube (320), and a spring (330). The cable (310) is connected to an actuator and a bell crank (132) to transmit power applied from the actuator to the robot finger (10). In this case, the cable (310) may be composed of a cable with a larger diameter to withstand a higher compressive force than a conventional cable. Here, the cable (310) includes a power transmission cable (131).

[0228] According to one embodiment of the present invention, the cable (310) is made of a material with a high elastic modulus, such as a nickel-titanium alloy (NiTi), and can absorb shock caused by an external force applied to the cable (310). Here, the external force may be a force transmitted from the object (OB) to the cable assembly (300) when the robot finger (10) grasps the object (OB) or comes into contact with or collides with the object (OB).

[0229] According to one embodiment of the present invention, a tube (320) is positioned to surround the outer surface of a cable (310) to guide the path of the cable (310). Specifically, the inner diameter of the tube (320) may match the outer diameter of the cable (310) or have a difference of less than or equal to a predetermined threshold. Accordingly, the inner surface of the tube (320) is in contact with the outer surface of the cable (310), so that the tube (320) can stably maintain the path of the cable (310). In addition, the tube (320) can prevent local deformation of the cable (310). Specifically, the tube (320) can prevent minute buckling or bending of the cable (310).

[0230] According to one embodiment of the present invention, the tube (320) can enable smooth operation of the cable (310) in contact with its inner surface. Specifically, the inner surface of the tube (320) may include materials with a low coefficient of friction, such as Teflon (PTFE), polyetheretherketone (PEEK), polyurethane, nylon, silicone, and ethylene tetrafluoroethylene (ETFE). Accordingly, the cable (310) can move smoothly within the tube (320) without stick-slip.

[0231] According to one embodiment of the present invention, the spring (330) is positioned to wrap around the outer surface of the tube (320). For example, when a tensile force is applied to the cable (310) from the actuator, the tensile force also acts on the tube (320) surrounding the cable (310). The spring (330) surrounding the outer surface of the tube (320) can serve to prevent the tube (320) from being tensed by the tensile force. Accordingly, since the tube (320) is not tensed, the cable (310) surrounding the tube (320) is also not tensed, and thus the tensile force applied to the cable (310) is transmitted directly to the bell crank (132). Additionally, when a compressive force is applied to the cable (310) from the actuator, a compressive force is also applied to the tube (320) surrounding the cable (310), and the spring (330) surrounding the outer surface of the tube (320) can act to prevent the tube (320) from being compressed by the compressive force. Accordingly, since the tube (320) is not compressed, the cable (310) surrounding the tube (320) is also not compressed, and thus the compressive force applied to the cable (310) is transmitted to the bell crank (132) as is.

[0232] In summary, when a tensile or compressive force is applied to the cable (310), the spring (330) can prevent the tube (320) from being deformed by the compressive or tensile force, which is a reaction force to the tensile or compressive force applied to the cable (310), thereby enabling power transmission through the cable (310).

[0233] According to one embodiment of the present invention, the spring (330) can enable accurate displacement transmission by the cable (310). Here, accurate displacement transmission may mean that the input displacement applied to the cable (310) from the actuator is transmitted to the bell crank (132) through the cable (310) without loss.

[0234] FIG. 17 is a conceptual diagram illustrating displacement transmission of a cable assembly according to an embodiment of the present invention. Specifically, FIG. 17 (a) is for illustrating displacement transmission when a tensile force is applied to the cable (310) in a linear actuator, and FIG. 17 (b) is for illustrating displacement transmission when a compressive force is applied to the cable (310) in a linear actuator.

[0235] As illustrated in FIG. 17(a), the spring (330) can prevent deformation of the cable (310) so that accurate displacement transmission by tensile force is achieved even if the cable (310) is arranged in a curved shape. Specifically, the cable (310) may be in an initial state (S1) in a static equilibrium state without any external force being applied. Additionally, when the cable (310) is in the initial state (S1), the spring (330) may be placed on the outside of the cable (310) in a compressed state. At this time, the coils of the spring (330) in the compressed state form a structure in close contact with each other, so that the spring (330) may not be compressed further even if it receives additional compressive force. Furthermore, the spring (330) in the compressed state occupies the space where the cable (310) in the initial state (S1) attempts to become a straight state (S2), so that the cable (310) does not have slack even when in the initial state (S1). Accordingly, even if a tensile force is applied to the cable (310), the path length of the cable (310) in the initial state (S1) can be maintained at the same or below a predetermined threshold, and accurate displacement transmission can be achieved immediately without delay, such as a slack removal process.

[0236] As illustrated in FIG. 17(b), the spring (330) can serve to prevent the cable (310) from buckling due to compressive force. Specifically, when the cable (310) is in an initial state (S1), the spring (330) can be positioned on the outside of the cable (310) in a tensioned state. At this time, the cable (310) is not further bent by the compressive force due to the spring (330) in the tensioned state. That is, even if a compressive force is applied to the cable (310), it does not buckle, and the path length of the cable (310) in the initial state (S1) can be maintained at the same or below a predetermined threshold, and an accurate displacement transmission can be achieved immediately.

[0237] In summary, the spring (330) enables immediate and accurate displacement transmission even when tensile and compressive forces are applied to the cable (310). That is, the cable (310) can always maintain a state capable of transmitting force through the spring (330). Accordingly, unlike conventional cable driving methods, a tension adjustment device is unnecessary in the cable assembly (300). Additionally, since there is no initial tension or tension from an auxiliary spring in the cable (310), the frictional resistance of the cable (310) can be low.

[0238] FIG. 18 is a conceptual diagram illustrating displacement transmission of a general cable according to a comparative example of the present invention. Specifically, FIG. 18 (a) is for illustrating displacement transmission when a tensile force is applied to a general cable in a linear actuator, and FIG. 18 (b) is for illustrating displacement transmission when a compressive force is applied to a general cable in a linear actuator.

[0239] As illustrated in FIG. 18(a), a standard cable cannot perform accurate displacement transmission by tensile force when arranged in a curved shape. Specifically, since the standard cable is arranged in a curved shape, it has slack in the initial state (S1). Accordingly, when tensile force is applied to the standard cable, its shape changes in a direction that removes the slack, and displacement transmission is delayed during this process. For example, when tensile force is applied to the standard cable, it fails to maintain the path length of the initial state (S1), and accurate displacement transmission does not occur until it becomes a straight state (S2).

[0240] As illustrated in FIG. 18 (b), a standard cable buckles due to a compressive force. Specifically, when a compressive force is applied to a standard cable, the standard cable buckles from an initial state (S1) to a deformed state (S3). At this time, the length of the path of the standard cable increases due to buckling, and it is unable to effectively transmit the compressive force. Subsequently, even if a tensile force is applied, the transmission of displacement is delayed until the standard cable returns from the buckled deformed state (S3) to a straight state (S2).

[0241] FIG. 19 is a conceptual diagram illustrating a double spring structure according to an embodiment of the present invention. Specifically, FIG. 19 (a) is a diagram illustrating a double spring structure arranged inwardly and outwardly. Additionally, FIG. 19 (b) is a diagram illustrating a double spring structure arranged vertically.

[0242] As illustrated in FIG. 19(a), the cable assembly (300) may include a plurality of springs (330). Specifically, the cable assembly (300) may include a first spring (331) and a second spring (332). In this case, the first spring (331) may be positioned in a compressed state as a spring that wraps around the tube (320). Additionally, the second spring (332) may be positioned in a tensioned state as a spring that wraps around the first spring (331). Accordingly, when a tension force is applied to the cable (310), the cable (310) may be maintained at a length equal to or below a predetermined threshold value by the first spring (331), and accurate displacement transmission may be achieved. Additionally, when a compressive force is applied to the cable (310), the cable (310) is not buckled by the second spring (332) and the length of the path is maintained at the same or below a predetermined threshold value, so that accurate displacement transmission can be achieved.

[0243] As shown in FIG. 19 (b), the first spring (331) and the second spring (332) can be arranged vertically. Specifically, the first spring (331) and the second spring (332) form a structure in which they are in close contact with each other in a compressed state so that even if a tensile force is applied to the cable (310), the path length can be maintained at the same or below a predetermined threshold.

[0244] FIG. 20 is a drawing for explaining the arrangement of a cable assembly according to one embodiment of the present invention.

[0245] According to one embodiment of the present invention, a cable assembly (300) may be placed in a section of the cable (310) where buckling is expected to occur. Specifically, based on the Euler buckling formula [Equation 3] below, the section where buckling is expected to occur when a compressive force is applied to the cable (310) can be calculated. Subsequently, the section where buckling is expected can be surrounded by a tube (320) and a spring (330). For example, the cable assembly (300) may be placed in the section of the cable (310) between the palm portion (20) and the actuator.

[0246] [Equation 3]

[0247]

[0248] At this time, the Euler buckling formula is the buckling critical load (P cr Variables may include the material's modulus of elasticity (E), moment of inertia (I), effective buckling length factor (K), and effective length (L).

[0249] FIG. 21a is a drawing for explaining a cable passage in a palm portion according to an embodiment of the present invention. Specifically, FIG. 21a (a) is a drawing showing a cable passage (21) without a cable (310). Also, FIG. 21a (b) is a drawing showing a cable passage (21) including a cable (310).

[0250] As described, the palm portion (20) may include a cable passage (21) which is a path through which the cable (310) passes. Specifically, the diameter of the cable passage (21) may match the diameter of the cable (310) or have a difference of less than or equal to a predetermined threshold value. Accordingly, the cable passage (21) can constrain the cable (310) in the lateral direction, thereby limiting lateral deformation that may occur when a compressive force is applied to the cable (310). That is, the cable passage (21) can prevent buckling by limiting lateral deformation even when a compressive force is applied to the cable (310). At this time, the 'longitudinal direction' of the cable (310) refers to the length direction of the cable (310), and the 'lateral direction' may refer to a direction perpendicular to the length direction of the cable (310).

[0251] FIG. 21b is a drawing for explaining a cable guide member according to an embodiment of the present invention. Specifically, FIG. 21b (a) is a front view of a cable guide member (22). FIG. 21b (b) is a side view of a cable guide member (220). FIG. 21b (c) is a perspective view of a cable guide member (220).

[0252] As described, the cable guide member (22) may include a proximal joint fastening part (22-1, 22-2) fastened to a proximal joint (111), a palm fastening part (22-3, 22-4) fastened to a palm part (20), and a cable support part (22-5) supporting the cable (310).

[0253] FIG. 21c is a drawing illustrating the arrangement of a cable guide member according to an embodiment of the present invention. As shown, the cable guide member (22) may be a plurality of and may be arranged corresponding to each of the plurality of robot fingers (12, 13, 14, 15). Additionally, the cable guide member (22) may be arranged between the robot fingers (12, 13, 14, 15) and the palm portion (20).

[0254] FIG. 22 is a conceptual diagram illustrating the state of a robot finger according to an embodiment of the present invention. Specifically, FIG. 22 (a) is for illustrating the fully extended state (FES) of the robot finger (10), and FIG. 22 (b) is for illustrating the fully bent state (FFS) of the robot finger (10).

[0255] As illustrated in FIG. 22 (a), the fully extended state (FES) may be a state in which the proximal segment (111), middle segment (112), distal segment (113), and palm portion (20) are aligned in a line. As illustrated in FIG. 22 (b), the fully bent state (FFS) may be a state in which the proximal segment (111), middle segment (112), and distal segment (113) are bent to the limit of motion. Meanwhile, a singularity refers to a state in which a specific joint or link cannot move even when power is transmitted. Specifically, a singularity may refer to a state in which the segment portion (110), joint portion (120), or power transmission portion (130) cannot operate even when power is applied to the finger portion (10).

[0256] FIG. 23a is a conceptual diagram illustrating the avoidance of singularities when a tensile force is applied to a cable in the fully extended state (FES) of a robot finger according to one embodiment of the present invention. Specifically, FIG. 23a (a) is intended to illustrate the curved shape of the cable (310), and FIG. 23a (b) shows only the MCP joint (121), the bell crank (132), and the cable (310) to illustrate the principle of avoiding singularities based on the curved shape of the cable (310).

[0257] As illustrated in FIG. 23a (a), the bell rank (132) may include a first pivot (132-1) connected to the cable (310) and a rotational pivot (132-r) which serves as the rotational center of the bell rank (132). Additionally, the cable passage (21) is positioned spaced apart from the rotational pivot (132-r) and the MCP joint (121) in the x-axis direction, and the cable (310) exits the cable passage (21) in the z-axis direction and connects to the first pivot (132-1). At this time, since the length of the cable (310) path between the cable passage (21) and the first pivot (132-1) is short, the cable (310) may be arranged in a curved shape bent in the z-axis direction.

[0258] As illustrated in (b) of FIG. 23a, the line of action of the force (f) pulling the first pivot (132-1) by the cable (310) is separated from the MCP joint (121), so that a moment arm exists, and a torque proportional to this is generated at the MCP joint (121). Accordingly, no singularity occurs at the MCP joint (121). Likewise, the line of action of the force (f) pulling the first pivot (132-1) by the cable (310) is separated from the rotational pivot (132-r), so that a moment arm exists, and a torque proportional to this is generated at the rotational pivot (132-r). Accordingly, no singularity occurs at the rotational pivot (132-r). Although the case where a tensile force is applied to the cable (310) has been explained above, as can be seen from the principle of singularity avoidance, even when a compressive force is applied to the cable (310), even if the cable (310) pushes the first pivot (132-1), no singularity occurs in the MCP joint (121) and the rotational pivot (132-r).

[0259] FIG. 23b is a conceptual diagram illustrating that a singularity occurs when a tensile force is applied to a cable in a fully extended state (FES) of a robot finger according to a comparative example of the present invention. Specifically, FIG. 23b (a) is to illustrate the straight shape of the cable, and FIG. 23b (b) shows only the MCP joint (121), the bell crank (132), and the cable (310) to illustrate the principle of singularity occurring based on the straight shape of the cable.

[0260] As illustrated in FIG. 23b (a), in the absence of a cable passage (21) and a cable assembly (300), the cable may be arranged in a straight line extending along the z-axis direction along gravity. In this case, the cable passes through a rotational pivot (132-r) and an MCP joint (121).

[0261] As illustrated in (b) of FIG. 23b, the line of action of the force (f) pulling the first pivot (132-1) of the cable passes through the MCP joint (121), so there is no moment arm, and no torque is generated at the MCP joint (121). Accordingly, a singularity occurs at the MCP joint (121). Similarly, the line of action of the force (f) pulling the first pivot (132-1) of the cable passes through the rotational pivot (132-r), so there is a very small moment arm, and no torque is generated at the rotational pivot (132-r). Accordingly, a singularity occurs at the rotational pivot (132-r). Although the case where a tensile force is applied to the cable has been described above, as can be seen from the principle of singularity generation, even when a compressive force is applied to the cable, or even when the cable pushes the first pivot (132-1), singularities occur at the MCP joint (121) and the rotational pivot (132-r).

[0262] FIG. 23c is a conceptual diagram illustrating the avoidance of singularities when a tensile force is applied to a cable in the fully bent state (FFS) of a robot finger according to one embodiment of the present invention. Specifically, FIG. 23c (a) is intended to illustrate the limited range of motion of the Velcrok (132), and FIG. 23c (b) shows only the Velcrok (132) and the cable (310) to illustrate the principle of avoiding singularities based on the limited range of motion of the Velcrok (132).

[0263] As illustrated in FIG. 23c (a), the cable (310) can pull the first pivot (132-1) in the negative direction of the z-axis. At this time, the range of motion of the Velcrok (132) may be limited so that the first pivot (132-1) and the rotational pivot (132-r) are not aligned in the z-axis direction. Here, the limited range of motion of the Velcrok (132) is not limited to the z-axis direction of the present embodiment, and, for example, the range of motion of the Velcrok (132) may be limited so that the first pivot (132-1) and the rotational pivot (132-r) are not aligned in the direction in which the cable (310) pulls the first pivot (132-1).

[0264] As illustrated in (b) of FIG. 23c, the line of action of the force (f) pulling the first pivot (132-1) by the cable (310) is separated from the rotational pivot (132-r), so a moment arm (m) exists, and a torque proportional to this is generated at the rotational pivot (132-r). Accordingly, no singularity occurs at the rotational pivot (132-r). Although the case where a tensile force is applied to the cable (310) has been described above, as can be seen from the principle of singularity avoidance, even when a compressive force is applied to the cable (310), no singularity occurs at the rotational pivot (132-r) even if the cable (310) pushes the first pivot (132-1).

[0265] FIG. 23d is a conceptual diagram illustrating that a singularity occurs when a tensile force is applied to a cable in the fully bent state (FFS) of a robot finger according to a comparative example of the present invention. Specifically, FIG. 23d (a) is to illustrate the unrestricted range of motion of the bell crank (131'), and FIG. 23d (b) shows only the bell crank (131') and the cable (310) to illustrate the principle of how a singularity occurs based on the unrestricted range of motion of the bell crank (131').

[0266] As illustrated in (a) of FIG. 23d, the cable (310) can pull the first pivot (132-1') in the negative direction of the z-axis. Additionally, the bell crank (131') has an unrestricted range of motion and can rotate until the first pivot (132-1') and the rotational pivot (132-r') are aligned in the z-axis direction.

[0267] As illustrated in (b) of FIG. 23d, the line of action of the force (f) pulling the first pivot (132-1') by the cable (310) passes through the rotational pivot (132-r'), so there is no moment arm and no torque is generated at the rotational pivot (132-r'). Accordingly, a singularity occurs at the rotational pivot (132-r'). Although the case where a tensile force is applied to the cable (310) has been described above, as can be seen from the principle of singularity occurrence, even when a compressive force is applied to the cable (310), a singularity occurs at the rotational pivot (132-r') even if the cable (310) pushes the first pivot (132-1').

[0268] FIG. 24aa is a drawing for explaining the finger portion and palm portion of a robot hand according to the present invention.

[0269] As described above, the robot hand (1) includes a finger portion (10), a palm portion (20), and a forearm portion (30). Specifically, the finger portion (10) is composed of a plurality of artificial fingers corresponding to the user's fingers, and the finger portion (10) includes a finger proximal portion (11), a finger middle portion (12), and a finger distal portion (13). Among these, a metacarpophalangeal (MCP) joint (11-1) is located between the finger proximal portion (11) and the palm portion (20), and the MCP joint corresponds to a joint drive unit connecting the palm portion (20) and the finger portion (10). The first joint (11-11) of the present invention corresponds to a joint that performs abduction and adduction movements within the MCP joint. The second joint (11-12) of the present invention corresponds to a joint that performs flexion and extension movements within the same MCP joint. In a joint numbering system based on anatomical criteria, the MCP joint could be defined as the first joint, the PIP joint as the second joint, and the DIP joint as the third joint; however, in this invention, the two degrees of freedom of movement of the MCP joint are distinguished and functionally defined as the first joint and the second joint, respectively.

[0270] As described above, the palm portion (20) supports the finger portion (10) and contains a plurality of internal actuators (100) for driving joints. At this time, the motor control unit (111) located in the forearm portion (30) can control the internal actuators (100) for driving joints, thereby allowing for precise control of individual movements of each finger portion (10), such as abduction and adduction, flexion and extension.

[0271] In the following description, the front view refers to a drawing of the robot hand (1) viewed from the front (1aa-1) based on FIG. 24aa. Additionally, the rear view refers to a drawing of the robot hand (1) viewed from the rear (1aa-2) based on FIG. 24aa. Additionally, the left side view refers to a drawing of the robot hand (1) viewed from the left (1aa-3) based on FIG. 24aa. Additionally, the right side view refers to a drawing of the robot hand (1) viewed from the right (1aa-4) based on FIG. 24aa. Additionally, the top view refers to a drawing of the robot hand (1) viewed from the plane (1aa-5) based on FIG. 24aa. Additionally, the bottom view refers to a drawing of the robot hand (1) viewed from the bottom (1aa-6) based on FIG. 24aa.

[0272] As described above, the robot hand (1) mimics the overall proportions of a human hand, and the finger portion (10), including the thumb and four fingers, is driven independently to perform actions such as grasping, manipulating, and picking up objects. Since the joints and driving parts of the finger portion (10) of the present invention are densely arranged inside the palm portion (20), the present invention enables precise motion control while maintaining the external shape of the robot hand (1) in a compact manner.

[0273] FIG. 24ab is a drawing for explaining the back of the hand of the palm portion of a robot hand according to the present invention.

[0274] As described, the robot hand (1) includes a finger portion (10), a palm portion (20), and a forearm portion (30). Specifically, the palm portion (20) includes a palm surface (20-1) and a back surface (20-2). An internal actuator (100-2) for driving the second joint, to be described later, may be positioned in the direction of the back surface (20-2) of the palm portion (20).

[0275] FIG. 24ac is a drawing for explaining the positions of the first joint driving internal actuator and the second joint driving internal actuator according to the second embodiment of the present invention.

[0276] As described, the palm portion (20) includes a palm surface (20-1) and a back surface (20-2). Specifically, the internal actuator (100-2) for driving the second joint is located in the direction of the back surface (20-2) relative to the palm portion (20), and the internal actuator (100-1) for driving the first joint may be located in the direction of the palm surface (20-1) relative to the palm portion (20).

[0277] FIG. 25ba is a drawing to explain the problems of an actuator using a conventional LM guide.

[0278] As described above, an actuator utilizing a conventional LM guide (1ba-1) has a structure in which the LM guide (1ba-1) prevents the rotation of the screw nut (1ba-2). Accordingly, since the screw nut (1ba-2) does not rotate, the screw nut (1ba-2) can perform translational motion. Additionally, because the compressive force applied to the screw (1ba-3) is distributed through the conventional LM guide (1ba-1), the screw (1ba-3) does not bend. That is, although a compressive force is applied to the screw (1ba-3) based on the rotational motion of the motor (1ba-4), the conventional LM guide (1ba-1) distributes this force, thereby enabling stable linear motion of the screw nut (1ba-2). However, there is a disadvantage that the volume and weight of the entire conventional actuator increase due to the volume and weight of the conventional LM guide (1ba-1).

[0279] FIG. 25bb is a drawing for explaining the driving of an actuator that does not use an LM guide according to a first embodiment of the present invention.

[0280] As described, the movable universal joint (101-1) can restrict the rotation of the screw nut portion (131). Additionally, the output link (151) can be fixed and coupled to the screw nut portion (131). Accordingly, the rotational movement of the screw nut portion (131) can be restricted by the movable universal joint (101-1). Furthermore, the support universal joint (102-1) is configured to fix the position of the internal actuator (100) for joint driving, but to accommodate the rotation of the finger portion (10). That is, according to the first embodiment of the present invention, linear driving of the output link (151) is made possible by the movable universal joint (101-1) and the support universal joint (102-1) even without using an LM guide.

[0281] FIG. 25bc is a drawing for explaining the driving of an actuator that does not use an LM guide according to a second embodiment of the present invention.

[0282] As described above, in the case of an internal actuator (100) for joint driving that does not use an LM guide according to the second embodiment, it includes a fixed part (1bc-1) and a moving part (1bc-2). Specifically, the fixed part (1bc-1) includes a motor (110) configured to provide power to the finger part (10). Additionally, the moving part (1bc-2) includes a screw shaft (132) configured to rotate based on the power provided by the motor (110), a screw nut (131) rotatably coupled to the screw shaft (132), and an output link (110-1) screwed into the screw nut (131) and rotatably coupled to the finger part (10). At this time, the support universal joint (102-1) can restrict the rotation of the screw nut part (131).

[0283] Additionally, the output link (151) can be fixed and coupled to the screw nut portion (131). Accordingly, the rotational movement of the screw nut portion (131) can be constrained by the movable universal joint (101-1) and the support universal joint (102-1). Additionally, the bearing (121) is located at the bottom and top of the screw shaft (132) and can perform the role of constraining the rotational movement of the screw nut portion (131) together with the movable universal joint (101-1) and the support universal joint (102-1). According to the first embodiment of the present invention, linear driving of the screw nut (131) is made possible by the movable universal joint (101-1) and the support universal joint (102-1) even without using an LM guide.

[0284] FIG. 26 is a drawing illustrating a motor control unit for controlling a motor of an internal actuator for joint driving according to the present invention.

[0285] As described, the robot hand (1) includes a forearm portion (30). Specifically, the forearm portion (30) includes a motor control unit (111). More specifically, the motor control unit (111) can precisely adjust the position of the screw nut (131) through at least one control method among rotation angle control, rotation speed control, torque control, and impedance control of the motor (110). In this specification, 'screw shaft' and 'screw nut' are used as concepts including a ball screw, a lead screw, or a similar screw coupling mechanism.

[0286] FIG. 27a is a cross-sectional view illustrating in detail the structure of the coupling part and the bearing part included in the internal actuator for joint driving of the second embodiment of the present invention.

[0287] As described, the coupling part (120) is coupled to the output shaft of the motor (110). The output shaft of the motor (110) is located on the same axis as the screw shaft (132). That is, the coupling part (120) is coupled to the output shaft of the motor (110) and positioned between the motor (110) and the screw shaft (132) to perform the function of transmitting the rotational force of the motor (110) to the screw part (130). Specifically, the flange (121-1) surrounds the coupling part (120), and the screw shaft (132) is interference-fitted to the flange (121-1). Accordingly, the motor (110) and the screw shaft (132) are coupled and integrated by the coupling part (120) and the flange (121-1). Through this, the rotational force of the motor (110) is transmitted to the screw shaft (132) via the coupling part (120). In this specification, 'screw shaft' and 'screw nut' are used as concepts including ball screws, lead screws, or similar screw coupling mechanisms.

[0288] According to one embodiment of the present invention, the flange (121-1) is supported from the outside by a bearing (121). Specifically, the bearing (121) is arranged to surround the flange (121-1) and performs the function of separating and absorbing a thrust load applied from the outside. Accordingly, it is possible to prevent the thrust generated during the operation of the external environment or the screw part (130) from being directly transmitted to the motor (110). In summary, the bearing (121) serves to prevent damage that may be applied to the output shaft or internal structure of the motor (110) by external thrust, and to improve the durability of the motor (110). Therefore, the flange (121-1), the bearing (121), and the coupling part (120) can together form a structure for power transmission and external force distribution between the motor (110) and the screw shaft (132).

[0289] According to one embodiment of the present invention, a bearing (121) is positioned at the bottom of the screw portion (130) to maintain concentricity when the screw shaft portion (132) rotates and to perform the function of suppressing runout or vibration. Specifically, the bearing (121) is coupled to the outer circumference of the flange (121-1), and the inner race of the bearing (121) rotates together with the screw shaft portion (132), while the outer race of the bearing (121) is fixed to a fixed internal actuator first housing (110), thereby inducing the screw shaft portion (132) to rotate along a predetermined coaxial axis when the screw shaft portion (132) rotates. That is, due to the structure of the bearing (121), the screw shaft portion (132) can rotate stably without deviating from the central axis even during rotation, and can suppress runout or vibration. In particular, the present invention has a screw shaft portion (132) fixed to the motor (110) side and the opposite side of the screw shaft portion (132) arranged in a free cantilever manner, so that a bearing (121) is placed at the bottom.

[0290] The present invention is configured in a cantilever manner in which a screw shaft portion (132) is fixed to the motor (110) side to transmit rotational force, and the opposite end is freely positioned without a separate support structure. Such a cantilever structure allows the internal actuator (100) for joint driving to be slimly housed inside the palm portion (20), and contributes to structural simplification and weight reduction. Meanwhile, to prevent bending of the free end of the screw shaft portion (132), a bushing portion (150) is placed at the top of the internal actuator (100) for joint driving.

[0291] According to one embodiment of the present invention, the bushing portion (150) is positioned on the outer circumference of the upper portion of the second housing (160-2) of the internal actuator and performs the function of maintaining alignment so as not to cause axial shaking or bending while allowing rotational movement of the screw shaft portion (132). In addition, as described above, the present invention arranges the screw shaft portion (132) in a cantilever structure. Accordingly, since the upper free end of the internal actuator (100) for joint driving may become structurally unstable during rotation, the bushing portion (150) can provide the effect of improving the structural stability and rotational precision of the internal actuator (100) for joint driving.

[0292] According to one embodiment of the present invention, the screw portion (130) is a component of the internal actuator (100) for joint driving and performs the function of converting rotational motion by the motor (110) into linear motion. Specifically, the screw portion (130) includes a screw shaft portion (132) and a screw nut (131) that can move linearly along the screw shaft portion (132). The screw shaft portion (132) receives rotational force from the motor (110) through the coupling portion (120) and rotates, and a screw shaft groove (132-1) is formed on the outer surface of the screw shaft portion (132).

[0293] According to one embodiment of the present invention, the ball screw nut groove (131-1) of the screw nut (131) is inserted into the screw shaft groove (132-1) of the screw shaft portion (132), so that rotation is maintained in a fixed state and moves in a straight direction along a spiral path according to the rotation of the screw shaft portion (132). Accordingly, the screw nut (131) converts linear motion into rotational motion or translational motion of the finger portion (10) to induce joint actuation. In addition, the screw portion (130) is miniaturized and high-precision machined to be suitable for joint actuation.

[0294] According to the present invention, the internal actuator first housing (160-1) and the internal actuator second housing (160-2) accommodate each component constituting the joint-actuating internal actuator (100) and perform the function of fixing and protecting them in a mechanically integrated structure. Specifically, the internal actuator first housing (160-1) and the internal actuator second housing (160-2) provide a mechanical reference axis so that the motor (110), the coupling part (120) coupled to the motor (110), the screw part (130), the bearing (121), and the bushing part (150) can operate stably in an aligned state. In addition, the internal actuator first housing (160-1) and the internal actuator second housing (160-2) can be designed with a slim or thin structure to protect internal components from external shocks and vibrations and to be inserted into the palm part (300).

[0295] FIG. 27b is a drawing for illustrating a bearing, a bearing support ring, and a first housing coupling groove of an embedded actuator of a first embodiment of the present invention.

[0296] As described, a bearing (121) may be positioned inside the first housing coupling groove (160-11) of the first housing of the internal actuator (160-1), and a bearing support ring (121-2) may be positioned on the top of the bearing (121) to support the bearing (121). Additionally, the bearing support ring (121-2) has a C-shape. Specifically, the bearing support ring (121-2) has a C-shape so that it can be attached and detached from the top of the ball bearing (121) after the screw shaft portion (132) is pressed into and fixed to the flange (121-1).

[0297] According to one embodiment of the present invention, an internal actuator first housing covering (120-12) may be positioned at the lower end of the internal actuator first housing coupling groove (160-11) of the internal actuator first housing (160-1). The internal actuator first housing covering (120-12) is a rubber ring formed of an elastic material and is positioned between the internal actuator first housing (160-1) and the internal actuator second housing (160-2) to perform the function of sealing the coupling portion (160-3) between the two housings. Accordingly, the internal actuator first housing (160-1) and the internal actuator second housing (160-2) may have a sealed structure that is completely isolated from the external environment. In addition, the internal actuator first housing covering (120-12) effectively prevents the intrusion of moisture or dust from the outside, thereby preventing the internal parts of the joint-actuating internal actuator (100) from being damaged or contaminated. That is, the internal actuator first housing covering (120-12) can improve the waterproof and dustproof performance of the joint-actuating internal actuator (100).

[0298] FIG. 27c is a drawing showing a first cross-section of an internal actuator for joint driving in which a gap is formed between a coupling part and a flange according to a first embodiment of the present invention.

[0299] According to one embodiment of the present invention, a predetermined clearance (2e-1) may be formed between the coupling part (120) and the flange (121-1). Specifically, the clearance (2e-1) between the coupling part (120) and the flange (121-1) can effectively respond to axis alignment errors, mechanical deformation, or assembly tolerances that may occur during the assembly of the internal actuator (100) for joint driving. In addition, the clearance (2e-1) between the coupling part (120) and the flange (121-1) serves to prevent the internal actuator (100) for joint driving from falling into an over-constrained state.

[0300] Over-constraint refers to a state in which the degrees of freedom required for the internal actuator (100) for joint driving are unnecessarily restricted by multiple parts being in excessive contact with each other or forming excessive constraints. Generally, when the output shaft of the screw shaft (132) and the DC motor (110) are aligned, the degrees of freedom of rotation in the z-axis direction and the degrees of freedom of translation in the x-axis and y-axis directions must be secured so that normal driving is possible despite minor misalignment between the axes. However, if the coupling part (120) and the flange (121-1) are tightly coupled in both the axial direction and the left-right direction, the degrees of freedom of rotation and translation are completely constrained, and even minor assembly errors or deformations are not allowed, and as a result, problems such as vibration, abnormal load, and inability to operate may occur in the internal actuator (100) for joint driving.

[0301] In the present invention, by securing a gap between the coupling part (120) and the flange (121-1) in the first cross section of the internal actuator (100) for joint driving, the coupling part (120) can move or tilt within a minute range within the flange (121-1) even if there is a slight misalignment or installation deviation between the axes. Through this, even when the output shaft of the motor (110) and the screw shaft (132) are arranged in a line, it is possible to flexibly respond to realistic assembly errors or environmental variations. Furthermore, by securing a gap between the coupling part (120) and the flange (121-1) in the first cross section of the internal actuator (100) for joint driving, unnecessary mechanical stress on the coupling part (120) and the flange (121-1) can be minimized, thereby providing the effect of extending the lifespan of the parts.

[0302] FIG. 27d is a drawing showing a first cross-section of an embedded actuator for joint driving, in which a gap is formed between the coupling part and the flange according to the first embodiment of the present invention shown in FIG. 27c, so that a ball bearing support ring can be seen.

[0303] According to one embodiment of the present invention, a predetermined clearance (2e-1) may be formed between the coupling part (120) and the flange (121-1). Specifically, the clearance (2e-1) between the coupling part (120) and the flange (121-1) can effectively respond to axis alignment errors, mechanical deformation, or assembly tolerances that may occur during the assembly of the internal actuator (100) for joint driving. In addition, the clearance (2e-1) between the coupling part (120) and the flange (121-1) serves to prevent the internal actuator (100) for joint driving from falling into an over-constrained state.

[0304] As described, a bearing (121) may be positioned inside the first housing coupling groove (160-11) of the first housing of the internal actuator (160-1), and a bearing support ring (121-2) may be positioned on the top of the bearing (121) to support the bearing (121). Additionally, the bearing support ring (121-2) has a C-shape. Specifically, the bearing support ring (121-2) has a C-shape so that it can be attached and detached from the top of the ball bearing (121) after the screw shaft portion (132) is pressed into and fixed to the flange (121-1).

[0305] FIG. 27e is a drawing showing an example of a commonly used commercial coupling.

[0306] The illustrated commercial coupling (2g-1) has a number of slits (2g-2) formed in the center, configured to absorb fine misalignment or eccentricity between the axes. While such a commercial coupling (2g-1) has the advantage of being able to flexibly respond to axis alignment errors, it has disadvantages such as structural weakening due to the slits (2g-2), complexity of the manufacturing process, and increased costs.

[0307] In contrast, the present invention is configured to effectively address misalignment between axes without a separate cut section (2h-2) by forming a predetermined clearance between the coupling part (120) and the flange (121-1). Through this, the present invention can not only reduce manufacturing costs but also maintain the structural rigidity of the coupling part (120) and the flange (121-1), thereby improving durability and reliability. Therefore, the present invention has the effect of providing the same or improved functions with a simpler structure compared to conventional commercial couplings (2h-1).

[0308] FIG. 28a is a drawing for explaining the driving method of the first joint driving internal actuator and the second joint driving internal actuator according to the first embodiment of the present invention.

[0309] According to the present invention, the internal actuator (100-2) for driving the second joint according to the first embodiment (c1) is an internal actuator for controlling the flexion and extension movements of the finger proximal portion (11) of the finger portion (10), and can implement a linear motion driving mechanism based on a screw portion (130).

[0310] As described, the internal actuator (100-2) for driving the second joint is positioned in the direction of the back of the hand (20-2) relative to the palm portion (20) shown in FIG. 1ab and is arranged in the longitudinal direction of the finger portion (10), the upper end of the internal actuator (100-2) for driving the second joint is connected to the flexion / extension link portion (103) through a movable universal joint (101-1), and the lower end of the internal actuator (100-2) for driving the second joint is connected to the internal actuator support member (21) through a support universal joint (102-1).

[0311] FIG. 28b is a drawing for explaining an embedded actuator support member according to a first embodiment of the present invention.

[0312] FIG. 28c is a drawing for explaining the alignment position of an embedded actuator for joint driving according to a second embodiment of the present invention.

[0313] According to one embodiment of the present invention, the lower portion of the second joint-driving internal actuator (100-2) can be coupled to the internal actuator support member (21) through a support universal joint (102-1). Specifically, the internal actuator support member (21) performs the role of supporting the entire structure of the joint-driving internal actuator (100) so that the joint-driving internal actuator (100) operates precisely without shaking against vibrations or external forces occurring during the operation of the joint-driving internal actuator (100). In addition, the internal actuator support member (21) is configured to support the second joint-driving internal actuator (100-2) and the first joint-driving internal actuator (100-1) while maintaining a constant distance to prevent interference between each actuator, even when they are mounted together.

[0314] As described, it can be seen that the internal actuator (100-2) for driving the second joint according to the second embodiment of the present invention is located in the direction of the back of the hand of the robot hand (1), and the internal actuator (100-1) for driving the first joint is located in the direction of the palm of the robot hand (1).

[0315] In the first embodiment (c1), the flexion / extension link portion (103) is a rotational link portion for performing flexion and extension movements of the finger proximal portion (11), and is a portion where the output of the second joint drive internal actuator (100-2) is transmitted through the movable universal joint (101-1). Specifically, the flexion / extension link portion (103) is a rotational link portion corresponding to the finger proximal portion (11), and the rotational center of the flexion / extension link portion (103) is set along the pitch axis of the finger proximal portion (11). Accordingly, the linear movement generated by the second joint drive internal actuator (100-2) is converted into rotational movement around the flexion / extension link portion (103), thereby enabling the entire finger portion (10) to bend or extend.

[0316] The linear motion generated from the drive shaft of the internal actuator (100-2) for driving the second joint is transmitted to the flexion / extension link section (103) via the movable universal joint (101-1). At this time, the flexion / extension link section (103) is a rotating link responsible for the flexion movement of the finger proximal part (11), and causes the finger proximal part (11) to flex. In addition, the flexion / extension link section (103) is a rotating link responsible for the extension movement of the finger proximal part (11), and causes the finger proximal part (11) to extend. In summary, the movable universal joint (101-1) performs the role of converting the linear motion generated from the internal actuator (100-2) for driving the second joint into a flexion movement or an extension movement with the x-axis (1-a) of the finger proximal part (11) as the central axis.

[0317] When the internal actuator (100-2) for driving the second joint moves upward, the movable universal joint (101-1) rotates clockwise. Accordingly, the flexion / extension link portion (103) rotates clockwise, and at the same time, the finger portion (10) performs a flexion movement. Additionally, when the internal actuator (100-2) for driving the second joint moves downward, the movable universal joint (101-1) rotates counterclockwise. Accordingly, the flexion / extension link portion (103) rotates counterclockwise, and at the same time, the finger portion (10) performs an extension movement.

[0318] In the first embodiment (c1), the support universal joint (302-1) connects the lower end of the internal actuator (100-2) for driving the second joint to the internal actuator support member (21) of the palm portion (20) and allows for a linear movement freedom, thereby enabling the main body of the internal actuator (100-2) for driving the second joint to move up and down according to the reaction of the screw nut (131). Unlike the case where a general LM guide (Linear Motion Guide) is used, the structure of the support universal joint (102-1) allows the external guiding device of the internal actuator (100-2) for driving the second joint to be omitted, making the structure simple and enabling slim installation within the palm portion (20).

[0319] Previously, in order to stably induce linear movement of the internal actuator (100) for joint driving, it was necessary to separately install external guiding means such as an LM guide (Linear Motion Guide). Such external guiding means require additional parts such as rails and sliding blocks, and have the disadvantage of expanding the installation space and making the structure complex. However, in the present invention, by allowing linear movement in the up and down direction of the second internal actuator (100-2) for joint driving by means of a support universal joint (102-1), it is not necessary to install a separate guiding rail or guide structure on the outside of the internal actuator (100) for joint driving. Accordingly, the structure of the internal actuator (100) for joint driving is simplified, and there is an advantage that the internal actuator (100) for joint driving can be slimly mounted even in a narrow space within the palm portion (20).

[0320] In the first embodiment (c1), the entire body of the internal actuator (100-2) for driving the second joint moves due to the movable universal joint (101-1) and the support universal joint (102-1), thereby enabling power transmission of the motor (110) even without the presence of an LM guide. Specifically, the rotational force of the motor (110) is transmitted to the screw shaft portion (332) through the coupling portion (120), and accordingly, the ball screw nut (331) moves linearly along the screw shaft portion (132). At this time, the movable universal joint (101-1) allows the linear motion to be converted into rotational motion of the flexion / extension link portion (103), and the support universal joint (102-1) at the bottom allows the motor (110) to move, thereby enabling the internal actuator (100-2) for driving the second joint to maintain linear motion without a separate guiding device.

[0321] According to the present invention, the power transmission rotary joint (101-2) is located at the top of the first joint driving internal actuator (100-1) and corresponds to a joint driving part that rotates so that the linear driving force of the first joint driving internal actuator (100-1) can implement abduction and adduction movements of the finger proximal part (11). Specifically, the power transmission rotary joint (101-2) is rotatably coupled with an abduction / adduction link part (104). Accordingly, when the driving body of the first joint driving internal actuator (100-1) moves linearly up and down, the power transmission rotary joint (101-2) rotates around the abduction / adduction link part (104) by means of a reaction. Through this, abduction and adduction movements of the finger part (10) are implemented.

[0322] As described above, the support rotation joint (102-2) is installed at the bottom of the first joint drive internal actuator (100-1) and serves to support the first joint drive internal actuator (100-1) on the internal actuator support member (21). Specifically, the support rotation joint (102-2) allows axial driving to enable vertical linear movement of the first joint drive internal actuator (100-1), while simultaneously suppressing unnecessary tilting, twisting, or vibration that may occur during driving, thereby providing a stable driving environment.

[0323] As described, the internal actuator (100-1) for driving the first joint can move up and down in a straight line with respect to the support rotational joint (102-2). This movement (3c-5, 3c-6) of the internal actuator (100-1) for driving the first joint is transmitted as rotational motion to the abduction / adduction link section (104) through the upper power transmission rotational joint (101-2). Specifically, the abduction / adduction link section (104) can perform the function of rotating the finger section (10) (3c-3, 3c-4) together with the power transmission rotational joint (101-2). Accordingly, the linear motion (3c-5, 3c-6) of the internal actuator (100-1) for driving the first joint is converted into the rotational motion of the abduction / adduction link part (104), and the finger proximal part (11) can precisely perform the abduction (3c-3) or adduction (3c-4) motion of the finger part (10).

[0324] As illustrated, when the internal actuator (100-1) for driving the first joint moves upward (3c-5), the power transmission rotary joint (101-2) rotates clockwise (3c-2) with respect to FIG. 3c. Accordingly, the abduction / adduction link (104) rotates clockwise with respect to FIG. 3c, and at the same time, the finger part (10) performs an adduction (3c-4) movement. Additionally, when the internal actuator (100-1) for driving the first joint moves downward (3c-6), the power transmission rotary joint (101-2) rotates counterclockwise (3c-1) with respect to FIG. 3c. Accordingly, the abduction / adduction link (104) rotates counterclockwise with respect to FIG. 3c, and at the same time, the finger part (10) performs an abduction (3c-3) movement.

[0325] FIG. 29 is a drawing for explaining an example of driving an embedded actuator according to the angles of abduction / adduction movement and flexion / extension movement of a finger portion according to the first embodiment.

[0326] FIG. 29 (a) is a diagram illustrating the position change of the internal actuator (100-2) for driving the second joint and the internal actuator (100-1) for driving the first joint when the second joint (11-12) of the finger portion according to the first embodiment has an angle of 0 degrees and the first joint (11-11) has an angle of -30 degrees.

[0327] According to one embodiment of the present invention, the reason the internal actuator (100-2) for driving the second joint moves even though the angle of the second joint (11-12) is 0 degrees is due to a structural misalignment that occurs when performing an abduction / adduction operation. Specifically, the movable universal joint (101-1) located at the top of the internal actuator (100-2) for driving the second joint is connected to the flexion / extension link portion (103). At this time, even when the angle of the second joint (11-12) is 0 degrees, the position of the abduction / adduction link portion (104) and the position of the movable universal joint (101-1) do not completely coincide, so when an adduction or abduction operation is performed, translational movement occurs in the internal actuator (100-2) for driving the second joint. At this time, the position of the movable universal joint (101-1) connected to the flexion / extension link section (103) is spatially offset from the rotation axis of the abduction / adduction link section (104). This offset exists even when the flexion / extension angle is 0 degrees, and when an adduction or abduction operation is performed, the movable universal joint (101-1) causes a positional shift according to the rotation of the abduction / adduction link section (104). That is, the main body of the internal actuator (100-2) for driving the second joint connected through the movable universal joint (101-1) simultaneously undergoes a fine translational movement according to the adduction / abduction operation.

[0328] As illustrated, when the internal actuator (100-1) for driving the first joint moves upward (3c-5), the finger portion (10) can perform an adduction motion (3c-4). That is, FIG. 4(a) shows an embodiment in which the adduction motion (3c-4) of the finger portion (10) by the internal actuator (100-1) for driving the first joint is performed at -30 degrees as the internal actuator (100-1) for driving the first joint moves upward (3c-5).

[0329] FIG. 29(b) is a diagram illustrating the positional change of the internal actuator (100-2) for driving the second joint and the internal actuator (100-1) for driving the first joint when the second joint (11-12) of the finger portion according to the first embodiment has an angle of 90 degrees and the first joint (11-11) has an angle of -30 degrees.

[0330] As described, the internal actuator (100-2) for driving the second joint can perform the action of flexing the proximal part of the finger (11) forward by 90 degrees (3b-1) as it descends (3b-4). At the same time, when the internal actuator (100-1) for driving the first joint moves upward (3c-5), the finger part (10) can perform an adduction action (3c-4). That is, the finger is fully flexed by 90 degrees (3b-1) by the operation of the internal actuator (100-2) for driving the second joint, and the adduction action is performed in combination according to the upward movement (3c-5) of the internal actuator (100-1) for driving the first joint.

[0331] FIG. 29 (c) is a diagram illustrating the position change of the internal actuator (100-2) for driving the second joint and the internal actuator (100-1) for driving the first joint when the second joint (11-12) of the finger portion according to the first embodiment has an angle of 0 degrees and the first joint (11-11) has an angle of 30 degrees.

[0332] As described above, even though the angle of flexion / extension is 0 degrees, the position of the internal actuator (100-2) for driving the second joint can change. Specifically, the movable universal joint (101-1) located at the top of the internal actuator (100-2) for driving the second joint is connected to the flexion / extension link portion (103). At this time, even when the angle of the second joint (11-12) of the finger portion is 0 degrees, the position of the abduction / adduction link portion (104) and the position of the movable universal joint (101-1) do not completely coincide, so when an abduction / adduction operation is performed, translational movement occurs in the internal actuator (100-2) for driving the second joint.

[0333] That is, Fig. 29 (c) shows an embodiment in which the abduction movement (3c-3) of the finger portion (10) by the first joint driving internal actuator (100-1) is performed at 30 degrees as the first joint driving internal actuator (100-1) moves downward (3c-6).

[0334] FIG. 29 (d) is a diagram illustrating the positional change of the internal actuator (100-2) for driving the second joint and the internal actuator (100-1) for driving the first joint when the second joint (11-12) of the finger portion according to the first embodiment has an angle of 90 degrees and the first joint (11-11) has an angle of 30 degrees.

[0335] As illustrated, the internal actuator (100-2) for driving the second joint can perform the action of flexing the proximal part of the finger (11) forward by 90 degrees (3b-1) along the x-axis (1-a) of FIG. 1b as it descends (3b-4). Additionally, as the internal actuator (100-1) for driving the first joint moves downward (3c-6), the abduction action (3c-3) of the finger part (10) by the internal actuator (100-1) for driving the first joint can be performed by 30 degrees.

[0336] The scope of the present invention is not limited to the embodiments described above but may be implemented in various forms of embodiments within the scope of the appended claims. It is deemed that the scope of the claims of the present invention includes various modifications that are possible by anyone with ordinary knowledge in the technical field to which the invention pertains, without departing from the essence of the invention claimed in the claims.

Claims

1. In a robot hand that does not include a linear movement guide, palm area; and Includes finger portion; and The above palm portion is, It includes an internal actuator for joint driving configured to be disposed inside the palm portion; The above-mentioned built-in actuator for joint driving is, A motor configured to provide power to the finger portion above; A screw shaft configured to rotate based on power provided by the above motor; A screw nut configured to be rotatably coupled to the above screw shaft; and Includes an output link fixedly coupled to the above screw nut; and The above finger portion is, A universal joint rotatably coupled to an internal actuator for driving the joint; The above universal joint is, A movable universal joint coupled to one end of the above sliding block to allow the finger portion to have two degrees of freedom of flexion or extension and adduction or abduction; and It includes a supporting universal joint located at the bottom of the built-in actuator for driving the joint; and The above universal joint is, Configured to restrict the rotation of the above screw nut, Robot hand that does not include a linear movement guide.

2. In Paragraph 1, The above-mentioned support universal joint is, The position of the built-in actuator for driving the joint is fixed, but the rotation of the finger portion is accommodated. Robot hand that does not include a linear movement guide.

3. In Paragraph 1, The above output link is, It is fixedly coupled with the above screw nut, Configured to move only in a straight direction along the axial direction of the screw shaft, Robot hand that does not include a linear movement guide.

4. In Paragraph 1, The above-mentioned movable universal joint is, Combined at the top of the above output link, Configured so that flexion or extension and adduction or abduction movements of the finger portion are performed independently. Robot hand that does not include a linear movement guide.

5. In Paragraph 1, The above-mentioned built-in actuator for joint driving is, A bearing configured to further include a bearing configured to support the above screw shaft, Robot hand that does not include a linear movement guide.

6. In a robot arm assembly, First actuator; palm area; and Includes finger portion; and The above finger portion is, A robotic finger configured to perform bending and straightening movements; including The above robot finger is, A joint portion composed of two or more segments of the above-mentioned robot finger; A joint portion configured to become the rotation center of the above-mentioned segment; and A power transmission unit configured to transmit power to the node portion based on power applied from the first actuator; comprising The above-mentioned node section is, A proximal joint connected to the above-mentioned palm portion; and It includes an intermediate joint connected at the distal end of the proximal joint; and The above joint part is, An MCP joint, which is an axis to which the palm portion and the proximal segment are connected; and It includes a PIP joint, which is an axis to which the proximal segment and the intermediate segment are connected; The above power transmission unit is, A power transmission cable configured to transmit a first power applied from the first actuator; A bell crank configured to transmit first-second power based on the first power above; and A connecting link configured to transmit 1-3 power to the intermediate node based on the 1-2 power; Based on the first power source, torque is generated in at least one of the MCP joint and the PIP joint to cause the robot finger to be underdriven, Robot arm assembly.

7. In Paragraph 6, The above-mentioned node section is, Further comprising a distal node connected at the distal end of the above intermediate node, The above joint part is, It further includes a DIP joint, which is an axis to which the above intermediate joint and the above distal joint are connected, The above power transmission unit is, It further includes a cross link configured so that the above intermediate node and the above distal node are linked together, A configuration in which torque is generated in at least one of the MCP joint, the PIP joint, and the DIP joint based on the above first power so as to cause the robot finger to be underdriven, Robot arm assembly.

8. In Paragraph 6, The above connection link is, Includes a connecting link hole configured to prevent mechanical interference with the above bell crank; The above power transmission cable is, Configured to transmit the first power based on tension or tensile force, Robot arm assembly.

9. In Paragraph 6, The above robot arm assembly is, It further includes a second actuator; and The above power transmission unit is, It further includes an output link configured to transmit a second power applied from the second actuator to the proximal node; and Based on the second power source, at least one of the proximal segment and the intermediate segment is rotated to cause the robot finger to be underdriven, Robot arm assembly.

10. In Paragraph 9, The above-mentioned node section is, Further comprising a distal node connected at the distal end of the above intermediate node, The above joint part is, It further includes a DIP joint, which is an axis to which the above intermediate joint and the above distal joint are connected, The above power transmission unit is, It further includes a cross link configured so that the above intermediate node and the above distal node are linked together, Based on the first power source, torque is generated in at least one of the MCP joint, the PIP joint, and the DIP joint to cause the robot finger to be underdriven, and Based on the second power source, at least one of the proximal segment, the intermediate segment, and the distal segment is configured to rotate so that the robot finger is underdriven, Robot arm assembly.

11. In the case of a robot hand, palm area; and including at least one robotic finger; The above-mentioned at least one robot finger is, It is connected to at least one driver by a cable, and The above cable is, The outer surface of the above cable is surrounded by a tube, and The above tube is, The outer surface of the above tube is surrounded by a spring, and The above-mentioned at least one robot finger is, Configured to receive power applied to the cable from at least one actuator, Robot hand.

12. In Paragraph 11, The above spring is, When a tensile force is applied to the cable from at least one of the above actuators, it is configured to prevent deformation of the tube by a reaction force, and The above cable is, Configured to transmit the tensile force to the at least one robot finger by the above reaction force, Robot hand.

13. In Paragraph 11, The above spring is, When a compressive force is applied to the cable from at least one actuator, the tube is configured to prevent deformation by a reaction force, and The above cable is, Configured to transmit the compressive force to the at least one robot finger by the above reaction force, Robot hand.

14. In Paragraph 11, The above spring is, A first spring surrounding the above tube; and A second spring surrounding the first spring; including The first spring above is, It is placed in a compressed state, and The second spring mentioned above is, Deployed in a tensioned state, Robot hand.

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