Clamping devices, robots, and force information sensing methods

Abstract

This invention provides a gripping device, a robot, and a force information sensing method. The gripping device includes a housing, a plurality of interlocking gripping assemblies for gripping an object, and a drive assembly. Each interlocking gripping assembly includes a fingertip for gripping the object, a first rod, a second rod, and a third rod. The first rod is fixedly connected to the fingertip. The first end of the second rod is rotatably connected to the first end of the first rod, and the second end is rotatably connected to the housing. The first end of the third rod is rotatably connected to the second end of the first rod, and the second end is rotatably connected to the housing. The drive assembly is drively connected to the second end of the second rod to drive the second rod to rotate. The gripping device also includes a plurality of force sensors, at least three of which are respectively disposed in the first rod, second rod, third rod, and drive assembly, configured to measure the axial force of at least three of them when the gripping device is in static equilibrium, for calculating the force information output by the fingertip.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to a gripping device, a robot having the gripping device, and a method for sensing force information applied to the gripping device. Background Technology

[0002] The gripper is an important end effector in robots. Typically driven by a drive assembly, the gripper grasps or releases objects through its fingertips. During the grasping process, especially when handling fragile objects, it is crucial to maintain an appropriate and stable force applied by the fingertips. Therefore, monitoring the force output by the fingertips relative to the object is extremely important. Summary of the Invention

[0003] A first aspect of the present invention provides a clamping device, including a housing, a plurality of linkage clamping assemblies for cooperating with each other to clamp an object, and a drive assembly; each linkage clamping assembly includes a fingertip for clamping the object, a first rod, a second rod, and a third rod. The first rod is fixedly connected to the fingertip. A first end of the second rod is rotatably connected to the first end of the first rod, and a second end is rotatably connected to the housing. A first end of the third rod is rotatably connected to the second end of the first rod, and a second end is rotatably connected to the housing. The drive assembly is drively connected to the second end of the second rod to drive the second rod to rotate. The clamping device also includes a plurality of force sensors, at least three of which are respectively disposed in the first rod, the second rod, the third rod, and the drive assembly, configured to measure the axial force of at least three of them when the clamping device is in static equilibrium, for calculating the force information output by the fingertip.

[0004] In some embodiments, at least a third member is axially embedded with a force sensor to measure the axial force of the third member when the clamping device is in static equilibrium, wherein the axial force refers to the internal axial force of the third member.

[0005] In some embodiments, the drive assembly includes a motor, a lead screw, a nut, and a plurality of transmission components; the lead screw is connected to the output end of the motor so that the motor drives the lead screw to rotate axially; the nut cooperates with the lead screw, and when the lead screw rotates, the nut moves axially along the lead screw; the plurality of transmission components correspond to each link clamping assembly respectively, wherein a first end of the transmission component is rotatably connected to the nut, and a second end of the transmission component is fixedly connected to the second end of the second link, such that when the motor drives the lead screw to rotate axially, the nut drives the second link to rotate.

[0006] In some embodiments, the drive assembly includes a force sensor configured to measure the driving force output by the drive assembly along the axial direction of the lead screw.

[0007] In some embodiments, a plurality of force sensors are respectively embedded in the first, second, and third rods along the axial direction to measure the axial force of the first, second, and third rods respectively when the clamping device is in static equilibrium, wherein the axial force refers to the internal axial force of the first, second, and third rods.

[0008] In some embodiments, the force information includes the tangential force, normal force, and bending moment of the fingertip along the contact surface.

[0009] In some embodiments, the fingertip is also provided with a multi-degree-of-freedom sensor to measure force information of the fingertip when it is used to grip an object.

[0010] A second aspect of the present invention provides a robot including a gripping device, a position measuring device, and a control system according to any of the above embodiments; the position measuring device is used to measure the structural parameters and position parameters of a first link, a second link, and a third link; the structural parameters include the length values ​​of the first link, the second link, and the third link, and the position parameters include the attitude vectors of the first link, the second link, and the third link; the control system is used to acquire the measurement values ​​of the position measuring device and multiple force sensors when the gripping device is in static equilibrium, and to establish static models of the first link, the second link, the third link, and the drive assembly respectively, and to calculate the force information output by the fingertip.

[0011] A third aspect of the present invention provides a force information sensing method for a clamping device, which can be applied to any of the above-mentioned clamping devices, comprising: acquiring force measurement values ​​measured by multiple force sensors when the clamping device is in static equilibrium; measuring the structural parameters and position parameters of a first rod, a second rod, and a third rod; establishing static models of the first rod, the second rod, the third rod, and a driving assembly respectively based on the measured force measurement values, the measured structural parameters, and the position parameters, and calculating the force information output by the fingertip.

[0012] In some embodiments, establishing static models of the first member, the second member, the third member, and the driving assembly based on the measured force values, the measured structural parameters, and the positional parameters includes: simplifying the first member, the second member, and the third member into static two-force member models, simplifying the driving assembly and the second member into torque balance models, performing static force analysis on each model, and establishing static models of the first member, the second member, the third member, and the driving assembly respectively.

[0013] Details of one or more embodiments of the present invention are set forth in the following drawings and description. Other features, objects, and advantages of the invention will become apparent from the specification, drawings, and claims. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the following description of the embodiments will be briefly introduced. The accompanying drawings described below are only some embodiments of the present invention and do not constitute a limitation on the disclosure and protection scope of the present invention.

[0015] Figure 1 This is a schematic diagram of the clamping device according to an exemplary embodiment of the present invention.

[0016] Figure 2 for Figure 1 A schematic diagram of the rod model of the clamping device structure is shown.

[0017] Figure 3 for Figure 2 The force diagram of the first lever and fingertip of the clamping device is shown.

[0018] Figure 4 for Figure 2 The force diagram of the second member of the clamping device is shown.

[0019] Figure 5 for Figure 2 The force diagram of the third member of the clamping device is shown.

[0020] Figure 6 for Figure 2 The torque diagrams of the fourth and second links of the clamping device are shown.

[0021] Figure 7 This is a schematic diagram of the clamping device according to an embodiment of the present invention.

[0022] Figure 8 This is a schematic diagram of a part of the clamping device according to an embodiment of the present invention, showing that a force sensor is embedded in the rod.

[0023] Figure 9 This is a schematic diagram of a robot according to an embodiment of the present invention.

[0024] Figure 10 This is a flowchart illustrating a force information sensing method for a clamping device according to an embodiment of the present invention. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0026] In the description of this invention, it should be understood that terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0027] In this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, unless otherwise explicitly limited, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components or an interaction between two components. Furthermore, when an component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there can be an intervening component. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] The inventors discovered that in the field of robotic gripping devices, when a gripping device is used to hold an object, there are usually two measurement methods to obtain the force applied to the object by the fingertips of the gripping device.

[0029] First, a tactile sensor is placed directly on the fingertip of the gripping device. When the fingertip grips an object, the force applied to the object by the tactile sensor is directly measured. However, existing tactile sensors may still not be able to obtain reliable and accurate multi-degree-of-freedom force feedback information, so this method has not yet been widely used in related fields.

[0030] Secondly, considering that clamping devices are usually driven by motors, and the driving torque of a motor is related to its current, torque information can be obtained by monitoring the motor current of the clamping device. However, motor current is easily affected by external noise, making it impossible to obtain accurate torque information. In addition, torque information is only one component of the multi-degree-of-freedom force feedback information of the clamping device, and cannot reflect the multi-degree-of-freedom force information applied by the clamping device to the object.

[0031] However, as robotic grippers are increasingly used to perform complex grasping tasks, especially grasping fragile objects, it is crucial to monitor and maintain a stable and accurate gripping force applied by the gripper's fingertips.

[0032] The technical solution involved in this application is based on the principle of force and / or torque balance of the robot gripping device under static equilibrium, and calculates the output force of the gripping device's fingertips in order to improve the relevant technology.

[0033] Below, we will first combine Figure 1 The exemplary clamping device shown illustrates the inventive concept of this application.

[0034] Reference Figure 1 An exemplary clamping device 1 includes a housing 10, a first quadrilateral linkage clamping assembly 11 and a second quadrilateral linkage clamping assembly 12 mounted to the housing 10, and a drive assembly 30. The first quadrilateral linkage clamping assembly 11 and the second quadrilateral linkage clamping assembly 12 have similar structures and are symmetrically arranged. The drive assembly 30 drives the first quadrilateral linkage clamping assembly 11 and the second quadrilateral linkage clamping assembly 12 respectively, so that the clamping device 1 grips or releases the target object.

[0035] Taking the first quadrilateral linkage clamping assembly 11 as an example, it includes a fingertip 110, a first rod 111 fixedly connected to the fingertip 110, a second rod 112 and a third rod 113 respectively connected to the first rod 111. The first end of the second rod 112 is rotatably connected to the first end of the first rod 111, and the second end of the second rod 112 is rotatably connected to the housing 10. The first end of the third rod 113 is rotatably connected to the second end of the first rod 111, and the second end of the third rod 113 is rotatably connected to the housing 10. The drive assembly 30 may include a motor 31, a lead screw 32, a nut 33 and a transmission component 34. One end of the transmission component 34 is rotatably connected to the nut 33, and the other end is fixedly connected to the second end of the second rod 112. In this configuration, the rotation of the lead screw 32 can drive the nut 33 to move along the lead screw 32, and further drive the rotation of the second rod 112 through the transmission component 34, thereby driving the movement of the first rod 111 and the third rod 113. In other words, the motor 31 outputs a driving force along the axial direction of the lead screw 32, which drives the first lever 111, the second lever 112, and the third lever 113 to move through the transmission component 34, thereby realizing the movement of the fingertip 110. It should be understood that in other ways, the drive assembly 30 can drive the third lever 113 to move, so that the first lever 111 and the second lever 112 follow the movement of the third lever 113. Although the calculation process is slightly different, the force information sensing method proposed in this application can also be applied to this situation.

[0036] Figure 2 for Figure 1A schematic diagram of the clamping device 1, taking the first quadrilateral linkage clamping assembly 11 as an example, shows a fingertip 110, a first rod 111 fixedly connected to the fingertip 110, a second rod 112 and a third rod 113 arranged parallel to each other, and a fourth rod 114 equivalent to the driving force applied by the drive assembly along the axial direction of the lead screw. The fourth rod 114 is connected to the second rod 112 through a transmission member 34, applying a rotational torque to the second rod 112.

[0037] This application applies to a clamping device 1 clamping an object and the clamping device 1 being in a static equilibrium state, as described below. Figures 3 to 6 A detailed analysis is conducted on the forces acting on the fingertip 110, the first member 111, the second member 112, the third member 113, and the fourth member 114 in this state.

[0038] Figure 3 The force diagrams of the fingertip 110 and the first rod 111 of the clamping device 1 are shown. The fingertip 110 and the first rod 111 are fixedly connected; taking the entire device as the object of study, when the fingertip 110 and the first rod 111 are in static equilibrium, the force / moment balance equations of their planar force system are:

[0039] F 21，x +F 31，x +F tip，x =0 (1)

[0040] F 21，y +F 31，y +F tip，y =0 (2)

[0041] M tip +F 31，x (l tip +Δl1sinθ1)-F 31，y (Δl1cosθ1)+F 21，x (l tip +l1sinθ1)-F 21，y (l1cosθ1)=0 (3)

[0042] F 21，x cosθ1+F 21，y sinθ1=F1 (4)

[0043] Among them, F 21，x F is the horizontal component of the force exerted by the second member 112 on the first member 111. 21，y F is the perpendicular component of the force exerted by the second member 112 on the first member 111. 31，x F is the horizontal component of the force exerted by the third member 113 on the first member 111. 31 , y F is the perpendicular component of the force exerted by the third member 113 on the first member 111.tip，x F is the normal force of the fingertip relative to the object. tip，y M is the tangential force of the fingertip relative to the object. tip F1 is the bending moment of the fingertip 110, and F1 is the axial force of the first member 111. tip Let Δl1 be the length of the fingertip 110, Δl1 be the length of the line connecting the connection point of the first rod 111 and the third rod 113 to the connection point of the first rod 111 and the fingertip 110, l1 be the length of the first rod 111, and θ1 be the angle between the length direction of the first rod 111 and the horizontal direction.

[0044] As can be seen, the force analysis of the first member 111 and the fingertip 110 above includes a total of 4 equations and 9 unknowns, namely F 21，x F 21，y F 31，x F 31，y F tip，x F tip，y M tip F1, θ1. In the above equations, l tip Let l1 be the structural parameter of the fingertip 110, l1 be the structural parameter of the first member 111, and Δl1 be related to the structural parameters of the first member 111 and the third member 113. Therefore, l1 can be used to determine the structural parameters of the fingertip 110. tip l1 and Δl1 are considered as known quantities.

[0045] Figure 4 The force diagram of the second member 112 of the clamping device 1 is shown. Taking the second member 112 as the object of study, since the second member 112 is in static equilibrium, its force / moment balance equation for the planar force system is:

[0046] F 12，x +F 42，x =0 (5)

[0047] F 12，y +F 42，y =0 (6)

[0048] M 24 +F 12，y l2cosθ2-F 12，x l2sinθ2=0 (7)

[0049] F 12，x cosθ2-F 12，y sinθ2=F2 (8)

[0050] Among them, F 12，x F is the horizontal component of the force exerted by the first member 111 on the second member 112. 42，x F is the horizontal component of the force exerted by the fourth member 114 on the second member 112. 12，yF is the perpendicular component of the force exerted by the first member 111 on the second member 112. 42，y M is the vertical component of the force exerted by the fourth member 114 on the second member 112. 24 Let l2 be the rotational torque of the second member 112, l2 be the length of the second member 112, θ2 be the angle between the length direction and the horizontal direction of the second member 112, and F2 be the axial force of the second member 112.

[0051] In the above formula, F 12，x and F 21，x Equal in size, opposite in direction; F 12，y and F 21，y They are equal in size but opposite in direction.

[0052] As can be seen, the force analysis of the second member 112 includes a total of 4 equations and 4 unknowns, namely F 42，x F 42，y θ2, F2. In the above equations, l2 is a structural parameter of the second member 112, so l2 can be regarded as a known quantity.

[0053] Reference Figure 5 The force diagram of the third member 113 of the clamping device 1 is shown. Taking the third member 113 as the object of study, since the third member 113 is in static equilibrium, the force / moment balance equation of its planar force system is:

[0054] F 13，x +F 03，x =0 (9)

[0055] F 13，y +F 03，y =0 (10)

[0056]

[0057] F 13，x =F3cosθ2 (12)

[0058] F 13，y =F3sinθ2 (13)

[0059] Among them, F 13，x F is the horizontal component of the force exerted by the first member 111 on the third member 113. 03，x F is the horizontal component of the force exerted by the shell 10 on the third member 113. 13，y F is the perpendicular component of the force exerted by the first member 111 on the third member 113. 03，y F1 is the vertical component of the force exerted by the shell 10 on the third member 113, and F2 is the axial force of the second member 112.

[0060] In the above formula, F 13，x And the aforementioned F31，x Equal in size, opposite in direction; F 13，y And the aforementioned F 31，y They are equal in size but opposite in direction.

[0061] As can be seen, the force analysis of the third member 113 includes a total of 5 equations and 3 unknowns, namely F. 03，x F 03，y , F3.

[0062] Figure 6 The torque diagrams of the fourth link 114 and the second link 112 of the clamping device 1 are shown. Taking the fourth link 114 as the object of study, since the driving assembly 30 is in a static equilibrium state, the torque equation of its planar force system is:

[0063] M 42 =F4 l4 (14)

[0064] Among them, M 42 M is the torque exerted by the fourth link 114 on the second link 112, l4 is the perpendicular distance between the connection point of the second link 112 and the transmission member 34 and the extension direction of the fourth link 114, and F4 is the axial driving force of the fourth link 114. 42 And the aforementioned M 24 They are equal in size but opposite in direction.

[0065] As can be seen, the force analysis of the fourth member 114 includes one equation and one unknown, namely F4. In the above equation, l4 is the structural parameter of the second member 112 and the fourth member 114, so l4 can be regarded as a known quantity.

[0066] In summary, when the clamping device 1 is in static equilibrium, the force / moment balance equations of its equivalent four-link planar force system involve a total of 18 unknowns and 14 equations. Among these 18 unknowns, the included angles θ1 and θ2 are related to the static positions and attitudes of the first link 111, the second link 112, and the third link 113, and can therefore be obtained, for example, by the position encoder of the motor 31 and the attitude measurement device of the link. Thus, the above equations (1)-(14) include a total of 16 unknowns. Theoretically, two more unknowns should be measured to reduce the number of unknowns to 14. However, considering that two equations in the force analysis of the third link 113 both use the parameter F3, three more unknowns need to be measured to reduce the number of unknowns to 13. Thus, the output force information of the fingertip 110, such as the normal force F, can be solved through 14 equations. tip,x Tangential force F tip,y and bending moment M tip .

[0067] Based on the above inventive concept, some embodiments of this application aim to provide a clamping device 1. For any three of the first rod 111, the second rod 112, the third rod 113, and the fourth rod 114, that is, any three parameters of F1, F2, F3, and F4 are measured, the normal force F output by the fingertip 110 can be calculated according to the above equations (1)-(14). tip,x Tangential force F tip,y and bending moment M tip .

[0068] To achieve the above-described inventive concept, some embodiments of this application provide a clamping device, including a housing and a plurality of linkage clamping assemblies for cooperating with each other to clamp an object. Each linkage clamping assembly includes a fingertip for clamping the object, a first rod, a second rod, a third rod, and a drive assembly. The first rod is fixedly connected to the fingertip. The first end of the second rod is rotatably connected to the first end of the first rod, and the second end of the second rod is rotatably connected to the housing. The first end of the third rod is rotatably connected to the second end of the first rod, and the second end of the third rod is rotatably connected to the housing. The clamping device also includes a drive assembly, which is throttlely connected to the second end of the second rod for driving the second rod to rotate. Each linkage clamping assembly also includes a plurality of force sensors, at least three of which are respectively disposed in the first rod, the second rod, the third rod, and the drive assembly, configured to measure the axial force of at least three of them when the clamping device is in static equilibrium, for calculating the force information output by the fingertip. This force information may include the tangential force, normal force, and bending moment of the fingertip along the contact surface.

[0069] According to the embodiments of this application, when the fingertip of the clamping device clamps an object and is in a static equilibrium state, the output force information applied to the object by the fingertip can be calculated based on the principle of force and / or torque balance, so as to monitor the multi-degree-of-freedom force information applied to the object by the clamping device.

[0070] Reference Figure 7 Some embodiments of the present invention provide a clamping device 7, including a housing 70, a first linkage clamping assembly 71 mounted to the housing 70, and a second linkage clamping assembly 72. In other embodiments, the clamping device 7 may also include more linkage clamping assemblies, such as three or more linkage clamping assemblies. Two or more linkage clamping assemblies of the clamping device 7 cooperate with each other to clamp a target object. In this application, for ease of description, Figure 7 The clamping device 7 shown includes two linkage clamping assemblies (i.e., the first linkage clamping assembly 71 and the second linkage clamping assembly 72), and the two linkage clamping assemblies have similar structures and are arranged symmetrically.

[0071] Taking the first linkage clamping assembly 71 as an example, it includes a fingertip 710, a first rod 711 fixedly connected to the fingertip 710, a second rod 712 and a third rod 713 respectively connected to the first rod 711. The first end of the second rod 712 is rotatably connected to the first end of the first rod 711, and the second end of the second rod 712 is rotatably connected to the housing 70. The first end of the third rod 713 is rotatably connected to the second end of the first rod 711, and the second end of the third rod 713 is rotatably connected to the housing 70.

[0072] In one example, the rotation centers of the first end of the second link 712, the second end of the second link 712, the second end of the third link 713, and the first end of the third link 713 sequentially form the four vertices of a quadrilateral, thus forming a four-bar linkage. In another example, at least the second link 712 and the third link 713 are arranged parallel to each other. In yet another example, the rotation centers of the first end of the second link 712, the second end of the second link 712, the second end of the third link 713, and the first end of the third link 713 sequentially form the four vertices of a parallelogram, thus forming a parallelogram linkage mechanism.

[0073] The clamping device 7 also includes a drive assembly 30 for outputting a driving force in the axial direction. This drive assembly is drively connected to the second end of each second rod to drive the second rod to rotate, thereby realizing the relative movement of the first link clamping assembly 71 and the second link clamping assembly 72.

[0074] Combination Figure 1 In one example, the drive assembly 30 may include a motor 31, a lead screw 32, a nut 33, and a plurality of transmission members 34. The lead screw 32 is connected to the output end of the motor 31 so that the motor 31 drives the lead screw 32 to rotate axially. The nut 33 cooperates with the lead screw 32, and moves axially along the lead screw 32 when the lead screw 32 rotates. The plurality of transmission members 34 correspond to each link clamping assembly, wherein the first end of the transmission member 34 is rotatably connected to the nut 33, and the second end of the transmission member 34 is fixedly connected to the second end of the second rod 712, such that when the motor 31 drives the lead screw 32 to rotate axially, the nut 33 drives the second rod 712 to rotate. Based on this, the drive assembly 30 can output a driving force along the axial direction of the lead screw 32 through the motor 31.

[0075] Reference Figure 8 The diagram shows a structural schematic of a rod in some embodiments of this application, wherein a force sensor 80 is embedded in the rod along the axial direction to measure the axial force of the rod. Figure 8The rods can be applied to the first rod 711, the second rod 712, or the third rod 713 of the clamping device 7 in this application embodiment to measure the axial force of the rods. It can be understood that the axial force refers to the internal axial force of the first rod 711, the second rod 712, and the third rod 713.

[0076] The drive assembly 30 of the clamping device 7 may also be equipped with a force sensor 80 for measuring the axial driving force output by the drive assembly 30. In one example, combined with Figure 1 and Figure 8 The force sensor can also be embedded axially within the lead screw 32 to measure the axial force of the lead screw when the clamping device 7 is in static equilibrium. In other examples, the drive assembly 30 can also be arranged in other ways to detect the axial driving force output by the drive assembly 30, including, for example, the manner described in Chinese Patent Application Publication CN112351869A, the entire contents of which are incorporated herein by reference.

[0077] The following details an implementation method in which force sensors are provided in at least three of the first link 711, the second link 712, the third link 713, and the drive assembly 30 (whose axial driving force is equivalent to that of the fourth link) to calculate the output force information of the fingertip 710.

[0078] In the first example, axial force sensors are installed on the first link 711, the second link 712, and the third link 713. When the clamping device 7 is in static equilibrium, the axial force sensor of the first link 711 measures the axial force F1, the axial force sensor of the second link 712 measures the axial force F2, and the axial force sensor of the third link 713 measures the axial force F3. The above 14 force / torque balance equations can be organized into the matrix equations below, thereby allowing the solution of the normal force F output by the fingertip 710. tip，x Tangential force F tip，y and bending moment M tip .

[0079]

[0080]

[0081] In the second example, axial force sensors are installed on the second link 712, the third link 713, and the drive assembly 30. When the clamping device 7 is in static equilibrium, the axial force sensor of the second link 712 measures the axial force F2, the axial force sensor of the third link 713 measures the axial force F3, and the axial force sensor of the drive assembly 30 measures the axial force F4. Similarly, the normal force F output by the fingertip 710 can be solved using the above 14 force / torque balance equations. tip，x Tangential force F tip，yand bending moment M tip .

[0082] In the third example, axial force sensors are installed on the first link 711, the third link 713, and the drive assembly 30. When the clamping device 7 is in static equilibrium, the axial force sensor of the first link 711 measures the axial force F1, the axial force sensor of the third link 713 measures the axial force F3, and the axial force sensor of the drive assembly 30 measures the axial force F4. Similarly, the normal force F output by the fingertip 710 can be solved using the above 14 force / torque balance equations. tip，x Tangential force F tip，y and bending moment M tip .

[0083] In the fourth example, axial force sensors are installed on the first link 711, the second link 712, and the drive assembly 30. When the clamping device 7 is in static equilibrium, the axial force sensor of the first link 711 measures the axial force F1, the axial force sensor of the second link 712 measures the axial force F2, and the axial force sensor of the drive assembly 30 measures the axial force F4. Similarly, the normal force F output by the fingertip 710 can be solved using the above 14 force / torque balance equations. tip，x Tangential force F tip，y and bending moment M tip .

[0084] Considering that equations (12) and (13) in the force / torque balance equations for the third member 713 both involve F3, in a further embodiment, the third member 713 is equipped with an axial force sensor, and at least two of the first member 711, the second member 712, and the drive assembly 30 are optionally equipped with axial force sensors. When the clamping device 7 is in static equilibrium, the force / torque balance equation is established based on the static model, and the force readings of the multiple axial force sensors are substituted to solve for the normal force F output by the fingertip 710. tip,x Tangential force F tip,y and bending moment M tip .

[0085] The clamping device 7 can also be additionally equipped with a multi-degree-of-freedom sensor 714, see reference. Figure 7 A multi-degree-of-freedom sensor 714 can be installed on the fingertip 710 to directly measure the output force information of the fingertip 710. Based on this, the normal force F of the fingertip 710 can be solved using the static model of the clamping device 7. tip,x Tangential force F tip,y and bending moment M tip Based on this, the force information of other degrees of freedom of the fingertip 710 can also be measured by the multi-degree-of-freedom sensor 714, which is beneficial for monitoring the output force of other degrees of freedom of the fingertip 710.

[0086] Based on the same technical concept described above, and referring to Figure 9 Some embodiments of the present invention also provide a robot, including a gripping device 7, a position measuring device, and a control system as described in any of the above embodiments. The position measuring device is used to measure the structural and positional parameters of the first link 711, the second link 712, and the third link 713. The structural parameters include the length values ​​of the first link 711, the second link 712, and the third link 713, and the positional parameters include the attitude vectors of the first link 711, the second link 712, and the third link 713. The control system is used to acquire the measurement values ​​from the position measuring device and multiple force sensors when the gripping device 7 is in static equilibrium, and to establish static models of the first link 711, the second link 712, the third link 713, and the drive assembly 30, respectively, to calculate the force information output by the fingertip 710.

[0087] In one example, combining the force / torque balance equations (1) to (14) above, the clamping device 7 is equipped with at least three force sensors to measure at least three of the axial forces: the axial force F1 of the first member 711, the axial force F2 of the second member 712, the axial force F3 of the third member 713, and the axial force F4 of the drive assembly 30. The position measuring device is used to measure the structural and positional parameters of the first member 711, the second member 712, and the third member 713 to obtain the included angle parameters θ1, θ2, and the length parameter l. tip l1, l2, l4, and Δl1, etc. When the clamping device 7 is in static equilibrium, the control system establishes force / torque balance equations for each link of the clamping device 7, obtains the measurement values ​​from multiple force sensors and position measuring devices, and solves for the normal force F of the fingertip 710. tip,x Tangential force F tip,y and bending moment M tip .

[0088] It is understood that other structural details of the robot in this embodiment can be referred to the relevant description of the aforementioned embodiment of the clamping device 7, and will not be repeated here.

[0089] Based on the same technical concept described above, this embodiment of the invention also provides a force information sensing method, which can be applied to any of the aforementioned clamping devices 7 and robots. (Refer to...) Figure 10 The force information sensing method includes the following steps.

[0090] In S1, when the clamping device is in static equilibrium, force measurement values ​​from multiple force sensors are acquired.

[0091] In one example, the clamping device 7 is equipped with at least three force sensors. When the clamping device 7 is in static equilibrium, at least three axial forces are obtained from the first rod 711 axial force F1, the second rod 712 axial force F2, the third rod 713 axial force F3, and the fourth rod axial force F4 based on the force sensors.

[0092] In S2, the structural and positional parameters of the first, second, and third members are measured.

[0093] In one example, when the clamping device 7 is in static equilibrium, based on the position and orientation of the linkage clamping assembly of the clamping device 7, the following parameters are obtained: the angle Δ1 between the length direction and the horizontal direction of the first link 711, the angle θ2 between the length direction and the horizontal direction of the second link 712; the length l1 of the first link 711, the length l2 of the second link 712, the length Δl1 of the line connecting the connection point of the first link 711 and the third link 713 to the connection point of the first link 711 and the fingertip 710, and the vertical distance l4 between the connection point of the second link 712 and the transmission component and the axial extension direction of the drive assembly 30.

[0094] In S3, based on the force measurements taken in S1 and the structural and positional parameters taken in S2, static models of the first member, the second member, the third member, and the drive assembly are established respectively, and the output force information of the fingertip is calculated.

[0095] In one example, when the clamping device 7 is in static equilibrium, the first link 711, the second link 712, and the third link 713 are simplified as two-force members, and the driving assembly 30 and the second link 712 are simplified as torque models. Static force analysis is performed on each model, and the force / torque balance equations of the planar force system of the first link 711, the second link 712, the third link 713, and the driving assembly 30 are established respectively, so as to solve for the normal force F output by the fingertip 710. tip,x Tangential force F tip,y and bending moment M tip .

[0096] It is understood that other implementation details of the force information sensing method in this embodiment can be found in the relevant descriptions of the aforementioned clamping device 7 and robot embodiments, and will not be repeated here.

[0097] In summary, the gripping device, robot, and force information sensing method provided by the embodiments of the present invention, by incorporating an axial force sensor within the levers and / or drive components of the gripping device, and establishing the force / torque balance equation of the planar force system of the levers and / or drive components when the gripping device is in a static equilibrium state, can calculate the output force information of the fingertip, thereby monitoring the multi-degree-of-freedom force information output by the fingertip of the gripping device. Furthermore, by monitoring the multi-degree-of-freedom force information applied by the fingertip to the object, it is beneficial to maintain a stable and accurate gripping force applied by the gripping device relative to the object, thereby improving the robustness and adaptability of the robot gripping device.

[0098] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0099] The technical features of the above embodiments can be combined arbitrarily according to the actual situation. In order to simplify the description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A clamping device, comprising: case; Multiple linkage clamping assemblies, which cooperate with each other to clamp an object, each linkage clamping assembly includes: Fingertips, used for gripping objects; The first rod is fixedly connected to the fingertip; A second rod, the first end of which is rotatably connected to the first end of the first rod, and the second end of which is rotatably connected to the housing; and The third rod has its first end rotatably connected to the second end of the first rod, and its second end rotatably connected to the housing. A drive assembly, which is drively connected to the second end of the second rod for driving the second rod to rotate; and Multiple single-axis axial force sensors are respectively embedded axially inside at least three of the first rod, the second rod, the third rod, and the drive assembly. They are configured to measure the internal axial force of the at least three components when the clamping device is in static equilibrium. This is used to establish a static model based on the structural and positional parameters of the first rod, the second rod, and the third rod to calculate the force information output by the fingertip. The force information includes the tangential force, normal force, and bending moment of the fingertip along the contact surface.

2. The clamping device according to claim 1, wherein, At least one of the uniaxial force sensors is embedded in the third member along the axial direction to measure the internal axial force of the third member when the clamping device is in static equilibrium.

3. The clamping device according to claim 1, wherein, The driving component includes: Electric motor; A lead screw, which is connected to the output end of the motor, so that the motor can drive the lead screw to rotate axially; A nut, which engages with the lead screw, and which moves axially along the lead screw when the lead screw rotates; and Multiple transmission components are provided, each corresponding to one of the connecting rod clamping assemblies. The first end of each transmission component is rotatably connected to the nut, and the second end of each transmission component is fixedly connected to the second end of the second rod, such that when the motor drives the lead screw to rotate axially, the nut drives the second rod to rotate.

4. The clamping device according to claim 3, wherein, The drive assembly is provided with the axial force sensor, which is configured to measure the driving force output by the drive assembly along the axial direction of the lead screw.

5. The clamping device according to claim 1, wherein, The plurality of force sensors are respectively embedded in the first rod, the second rod and the third rod along the axial direction, so as to measure the internal axial force of the first rod, the second rod and the third rod respectively when the clamping device is in static equilibrium.

6. The clamping device according to claim 1, wherein, The fingertip is also equipped with a multi-degree-of-freedom sensor to measure the force information of the fingertip when it is used to grip an object.

7. A robot comprising the gripping device as described in any one of claims 1 to 6, the robot further comprising: A position measuring device for measuring the structural and positional parameters of the first, second, and third rods; The structural parameters include the length values ​​of the first link, the second link, and the third link; the position parameters include the attitude vectors of the first link, the second link, and the third link; and The control system is used to acquire the measurement values ​​of the position measuring device and the plurality of single-axis axial force sensors when the clamping device is in static equilibrium, and to establish static models of the first rod, the second rod, the third rod and the drive assembly respectively, and to calculate the force information output by the fingertip.

8. A force information sensing method, applied to the clamping device as described in claim 1, comprising: When the clamping device is in static equilibrium, the force measurement values ​​of the plurality of single-axis axial force sensors are acquired; Measure the structural and positional parameters of the first member, the second member, and the third member; and Based on the measured force values, measured structural parameters, and positional parameters, static models of the first rod, the second rod, the third rod, and the driving assembly are established respectively, and the force information output by the fingertip is calculated, wherein the force information includes the tangential force, normal force, and bending moment of the fingertip along the contact surface.

9. The method according to claim 8, wherein, Based on the measured force values, measured structural parameters, and positional parameters, static models of the first member, the second member, the third member, and the drive assembly are established, including: The first, second, and third links are simplified into two-force member models, and the drive assembly and the second link are simplified into torque balance models. Static force analysis was performed on the two-force member model and the moment equilibrium model. Static models of the first rod, the second rod, the third rod, and the drive assembly are established respectively.

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