Grip device, robot, and force information sensing method

Abstract

The present invention provides a gripping device, a robot, and a force information sensing method. The gripping device (1, 7) includes a case (10, 70), a plurality of coupled gripping assemblies (11, 12, 71, 72) that engage with each other to grip an object, a drive assembly (30), and a plurality of load cells. Each of the connecting gripping assemblies (11, 12, 71, 72) includes a fingertip (110, 710), a first link (111, 711) fixedly connected to the fingertip (110, 710), a second link (112, 712) having a first end rotatably connected to the first end of the first link (111, 711) and a second end rotatably connected to the case (10, 70), and a third link (113, 713) having a first end rotatably connected to the second end of the first link (111, 711) and a second end rotatably connected to the case (10, 70). The drive assembly (30) is operatively connected to the second end of the second link (112, 712) and rotates the second link (112, 712). Each load cell is installed on at least three members of the first link (111, 711), the second link (112, 712), the third link (113, 713) and the drive assembly (30).

Description

[Technical Field]

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

[0002] A gripping device is an important terminal execution mechanism in a robot. A gripping device is usually driven by a drive assembly and realizes grasping or releasing of an object with its fingertips. When a gripping device grasps an object, especially a fragile object, it is necessary to maintain an appropriate and stable acting force applied to the object from the fingertips. Therefore, it is very important to monitor the force information output by the fingertips against the object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent Application Publication No. 112351869 Summary of the Invention

[0004] A first aspect of the present invention provides a gripping device including a case, a plurality of linked gripping assemblies adapted to grip an object by interlocking with one another, and a drive assembly, each linked gripping assembly including a fingertip configured to grip an object, a first link, a second link, and a third link. The first link is fixedly connected to the fingertip. The second link has a first end rotatably connected to the first end of the first link and a second end rotatably connected to the case. The third link has a first end rotatably connected to the second end of the first link and a second end rotatably connected to the case. A drive assembly is drivably connected to the second end of the second link to rotate the second link. The gripping device further includes a plurality of load cells, each of which is installed on at least three members of the first link, the second link, the third link, and the drive assembly, and is configured to measure the axial forces of the at least three members of the gripping device in a static equilibrium state and calculate force information output by the fingertip.

[0005] A second aspect of the present invention provides a robot including any one of the gripping devices described above, a position measurement device, and a control system. The position measurement device measures structural parameters and position parameters of a first link, a second link, and a third link. The structural parameters include lengths of the first link, the second link, and the third link, and the position parameters include attitude vectors of the first link, the second link, and the third link. The control system acquires measurements from the position measurement device and measurements from multiple load cells when the gripping device is in a static equilibrium state, constructs static models of each of the first link, the second link, the third link, and the drive assembly, and calculates force information output by the fingertips.

[0006] A third aspect of the present invention provides a method for sensing force information of a gripping device, which is applicable to any of the gripping devices described above, the method including the steps of: acquiring force measurement values of a plurality of load cells when the gripping device is in a static equilibrium state; measuring structural parameters and positional parameters of the first link, the second link, and the third link; and constructing static models of each of the first link, the second link, the third link, and the drive assembly based on the force measurement values, the structural parameters, and the positional parameters, and calculating force information output by the fingertips.

[0007] The details of one or more embodiments of the invention are set forth in the drawings and description that follow. Other features, objects, and advantages of the invention will become apparent from the description, drawings, and claims.

[0008] In order to more clearly explain the technical aspects of the embodiments of the present invention, the following will briefly describe the drawings to be used in the description of the embodiments. However, the drawings described below are only some embodiments of the present invention and do not limit the disclosure content and protection scope of the present invention. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating a configuration of a gripping device according to an exemplary embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of a link model of the configuration of the gripping device in FIG. 1. [Figure 3] 3 is a force diagram of a first link and a fingertip of the gripping device in FIG. 2. [Figure 4] 3 is a force diagram of a second link of the gripping device in FIG. 2. FIG. [Figure 5] 3 is a force diagram of a third link of the gripping device in FIG. 2. FIG. [Figure 6] 3 is a moment diagram of the fourth link and the second link of the gripping device in FIG. 2. FIG. [Figure 7] 1 is a schematic diagram illustrating a configuration of a gripping device according to an embodiment of the present invention. [Figure 8] FIG. 1 is a schematic diagram of a portion of a link of a gripping device according to one embodiment of the present invention, showing that a load cell is embedded within the link. [Figure 9] 1 is a schematic diagram of a robot according to an embodiment of the present invention. [Figure 10] 1 is a flowchart of a method for sensing force information of a gripping device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] In order to clarify the above-mentioned objects, features, and advantages of the present invention, specific embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, specific contents are set forth to fully understand the present invention, but the present invention can be implemented in embodiments different from the contents set forth in this specification, and those skilled in the art can make improvements without departing from the spirit of the present invention. Therefore, the present invention is not limited to the following specific embodiments.

[0011] In describing the present invention, 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," "circumferential," and the like, indicate orientations or positional relationships based on those shown in the accompanying drawings, are used solely to facilitate and simplify the description of the present invention, and are not intended to expressly or imply that the referenced devices or elements must have a particular orientation, be configured, or operate in a particular orientation, and therefore should not be construed as limitations of the present invention.

[0012] In the present invention, unless otherwise clearly defined or limited, terms such as "attached," "contacted," "connected," "fixed," and "installed" should be understood in a broad sense. For example, unless otherwise clearly defined, "connected" may be a fixed connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, a relationship in which two elements communicate with each other, or a relationship in which two elements interact with each other. For example, when an element is said to be "fixed" or "installed" to another element, it may be directly located on the other element, or there may be an intermediate element. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific situation.

[0013] The inventor has discovered that in the field of robotic gripping devices, when a gripping device grips an object, the force exerted by the fingertips of the gripping device on the object is generally obtained by two measurement methods.

[0014] In the first measurement method, a tactile sensor is directly attached to the fingertips of a gripping device, and the force applied by the fingertips to an object is directly measured by the tactile sensor when the fingertips grip the object. However, existing tactile sensors may not be able to reliably obtain accurate multi-degree-of-freedom force feedback information, and therefore this method has not yet been widely adopted in the field.

[0015] In the second measurement method, since the gripping device is usually driven by a motor and the driving torque of the motor is related to the motor current, it is possible to obtain torque information by monitoring the motor current of the gripping device. However, because the motor current is easily affected by external disturbances, accurate torque information cannot be obtained. Furthermore, torque information is only one component of the multi-degree-of-freedom force feedback information of the gripping device, and cannot reflect the multi-degree-of-freedom force information applied by the gripping device to an object.

[0016] Meanwhile, as robotic gripping devices are increasingly applied to complex gripping tasks, especially those involving the gripping of fragile objects, it becomes increasingly important to monitor and maintain the gripping device's fingertips to apply stable and accurate gripping forces.

[0017] The technical form of the present application improves on the related art by calculating the force output by the fingertips of a robotic gripping device based on the force and / or moment balance principle when the robotic gripping device is in a static equilibrium state.

[0018] The concept of the present invention will now be explained, first with reference to the exemplary gripping device in FIG.

[0019] 1 , the illustrated gripping device 1 includes a case 10, a first quadrilateral linkage gripping assembly 11 and a second quadrilateral linkage gripping assembly 12 attached to the case 10, and a drive assembly 30. The first quadrilateral linkage gripping assembly 11 and the second quadrilateral linkage gripping assembly 12 have similar configurations and are installed symmetrically. The drive assembly 30 drives the first quadrilateral linkage gripping assembly 11 and the second quadrilateral linkage gripping assembly 12, respectively, thereby enabling the gripping device 1 to grip or release an object.

[0020] Taking the first quadrilateral-linked gripping assembly 11 as an example, it includes a fingertip 110, a first link 111 fixedly connected to the fingertip 110, and a second link 112 and a third link 113 respectively connected to the first link 111. A first end of the second link 112 is rotatably connected to a first end of the first link 111, and a second end of the second link 112 is rotatably connected to the case 10. A first end of the third link 113 is rotatably connected to a second end of the first link 111, and a second end of the third link 113 is rotatably connected to the case 10. The drive assembly 30 includes a motor 31, a lead screw 32, a nut 33, and a transmission member 34, one end of the transmission member 34 being rotatably connected to the nut 33 and the other end being fixedly connected to the second end of the second link 112. With this arrangement, rotation of the lead screw 32 drives the nut 33 to move along the lead screw 32, which in turn rotates the second link 112 via the transmission member 34, thereby moving the first link 111 and the third link 113. In other words, the motor 31 outputs a driving force along the axial direction of the lead screw 32, and the transmission member 34 moves the first link 111, the second link 112, and the third link 113, thereby achieving movement of the fingertip 110. It is understood that in another embodiment, the drive assembly 30 may drive the third link 113 to move, causing the first link 111 and the second link 112 to follow the movement of the third link 113. Although the calculation process may be slightly different, the force information sensing method disclosed herein is equally applicable to the above scenario.

[0021] 2 is a schematic diagram of a link model of the gripping device 1 of FIG. 1, taking the first quadrilateral-linked gripping assembly 11 as an example, and showing a fingertip 110, a first link 111 fixedly connected to the fingertip 110, a second link 112 and a third link 113 installed parallel to each other, and a fourth link 114 corresponding to the driving force applied by the drive assembly along the axial direction of the lead screw. The fourth link 114 is connected to the second link 112 by a transmission member 34 and applies a rotational torque to the second link 112.

[0022] This application is applied when the gripping device 1 is gripping an object and is in a static equilibrium state, and with reference to Figures 3 to 6, a force analysis of the fingertip 110, the first link 111, the second link 112, the third link 113, and the fourth link 114 in this state will be described in detail.

[0023] 3 shows a force diagram of the fingertip 110 and first link 111 of the gripping device 1. The fingertip 110 is fixedly connected to the first link 111, and the entirety of the fingertip 110 is considered. When the fingertip 110 and the first link 111 are in a static equilibrium state, the force / moment equilibrium equation of the planar force system is as follows:

number

[0024] F 21、x is the horizontal component force of the second link 112 on the first link 111, and F 21、y is the vertical component force of the second link 112 on the first link 111, and F 31、x is the horizontal component force of the third link 113 on the first link 111, and F 31、y is the vertical component force of the third link 113 on the first link 111, and F tip、x is the normal force of the fingertip 110 on the object, and F tip、y is the tangential force of the fingertip 110 on the object, and M tip is the bending moment of the fingertip 110, F1 is the axial force of the first link 111, and l tip is the length of the fingertip 110, Δl1 is the length of the connecting line from the connection point of the first link 111 and the third link 113 to the connection point of the first link 111 and the fingertip 110, l1 is the length of the first link 111, and θ1 is the angle between the longitudinal direction of the first link 111 and the horizontal direction.

[0025] In the above-described force analysis of the first link 111 and the fingertip 110, a total of four equations and nine unknowns, namely, F 21、x , F 21、y , F31、x , F 31、y , F tip、x , F tip、y , M tip , F1, θ1. In the above equation, l tip is a structural parameter of the fingertip 110, l1 is a structural parameter of the first link 111, and Δl1 is related to the structural parameters of the first link 111 and the third link 113. tip , l1 and Δl1 can be considered as known quantities.

[0026] 4 shows a force diagram of the second link 112 of the gripping device 1. Taking the second link 112 as the object of consideration, and since the second link 112 is in static equilibrium, the force / moment equilibrium equations of its planar force system are as follows:

number

[0027] F 12、x is the horizontal component force of the first link 111 on the second link 112, and F 42、x is the horizontal component force of the fourth link 114 on the second link 112, and F 12、y is the vertical component force of the first link 111 on the second link 112, and F 42、y is the vertical component force of the fourth link 114 on the second link 112, and M 24 is the rotational torque of the second link 112, l2 is the length of the second link 112, θ2 is the angle between the longitudinal direction and the horizontal direction of the second link 112, and F2 is the axial force of the second link 112.

[0028] In the above formula, F 12、x and F 21、x are equal in magnitude and opposite in direction, but F 12、y and F 21、y are equal in magnitude and opposite in direction.

[0029] In the force analysis for the second link 112, there are a total of four equations and four unknowns: F42、x , F 42、y , θ2, and F2. In the above equation, l2 is a structural parameter of the second link 112, so l2 can be considered a known quantity.

[0030] Referring to the force diagram of the third link 113 of the gripping device 1 shown in FIG. 5, the third link 113 is taken as the object of consideration, and since the third link 113 is in a static equilibrium state, the force / moment equilibrium equation of its planar force system is as follows:

number

[0031] F 13、x is the horizontal component force of the first link 111 on the third link 113, and F 03、x is the horizontal component force of the case 10 on the third link 113, and F 13、y is the vertical component force of the first link 111 on the third link 113, and F 03、y is the vertical component force of the case 10 on the third link 113, and F3 is the axial force of the second link 112.

[0032] In the above formula, F 13、x and the aforementioned F 31、x are equal in magnitude and opposite in direction, but F 13、y and the aforementioned F 31、y are equal in magnitude and opposite in direction.

[0033] In the force analysis for the third link 113, there are a total of five equations and three unknowns, namely, F 03、x , F 03、y , including F3.

[0034] Referring to the moment diagram between the fourth link 114 and the second link 112 of the gripping device 1 shown in FIG. 6, taking the fourth link 114 as the object of consideration and the drive assembly 30 in a static equilibrium state, the torque equation of its planar force system is as follows:

number

[0035] M 42 is the torque that the fourth link 114 exerts on the second link 112, l4 is the perpendicular distance between the connecting point of the second link 112 and the transmission member 34 and the direction of extension of the fourth link 114, and F4 is the driving force of the fourth link 114 in the axial direction. 42 and the aforementioned M 24 are equal in magnitude and opposite in direction.

[0036] The force analysis for the fourth link 114 involves a total of one equation and one unknown quantity, namely, F4. In the above equation, l4 is a structural parameter of the second link 112 and the fourth link 114, so l4 can be considered as a known quantity.

[0037] Considering the above, when the gripping device 1 is in a static equilibrium state, the force / moment equilibrium equations for the equivalent four-link planar force system involve a total of 18 unknowns and 14 equations. Among the 18 unknowns, the angles θ1 and θ2 relate to the positions and orientations of the first link 111, the second link 112, and the third link 113 in the static state. These can be obtained, for example, by the position encoder of the motor 31 and the link orientation measurement device. Therefore, the above equations (1)-(14) include a total of 16 unknowns. Theoretically, the number of unknowns can be reduced to 14 by adding two additional unknown measurements. However, considering that there are two equations using the parameter F3 in the force analysis of the third link 113, it is necessary to measure three unknowns to reduce the number to 13. As a result, the force information output by the fingertip 110, such as the normal force F, can be calculated based on the 14 equations. tip、x , tangential force F tip、y and bending moment M tip can be obtained.

[0038] Based on the above-described concept of the invention, some embodiments of the present application provide a gripping device 1, which measures axial forces on any three of the first link 111, the second link 112, the third link 113, and the fourth link 114, i.e., measures any three parameters of F1, F2, F3, and F4, and calculates the force normal force F output by the fingertip 110 based on the above-described equations (1)-(14). tip、x , tangential force F tip、y and bending moment M tip It is possible to calculate

[0039] To realize the above-described inventive concept, some embodiments of the present application provide a gripping device including a case, a plurality of linked gripping assemblies that interlock with one another to grip an object, and a drive assembly, each linked gripping assembly including a fingertip configured to grip an object, a first link, a second link, and a third link. The first link is fixedly connected to the fingertip. The second link has a first end rotatably connected to the first end of the first link and a second end rotatably connected to the case. The third link has a first end rotatably connected to the second end of the first link and a second end rotatably connected to the case. The drive assembly is drivably connected to the second end of the second link to rotate the second link. The gripping device further includes a plurality of load cells, each of which is installed on at least three of the first link, the second link, the third link, and the drive assembly, and configured to measure axial forces of the at least three members of the gripping device in a static equilibrium state and calculate force information output by the fingertip, including a tangential force, a normal force, and a bending moment along the contact surface of the fingertip.

[0040] According to an embodiment of the present application, when the fingertips of a gripping device are gripping an object and are in a static equilibrium state, the gripping device can calculate force information output from the fingertips and applied to the object based on the force and / or moment equilibrium principle, and monitor the multi-degree-of-freedom force information applied to the object by the gripping device.

[0041] Referring to FIG. 7 , some embodiments of the present invention provide a gripping device 7, which includes a case 70 and a first and second coupled gripping assembly 71 and 72 attached to the case 70. In other embodiments, the gripping device 7 may include more coupled gripping assemblies, for example, three or more coupled gripping assemblies. The two or more coupled gripping assemblies in the gripping device 7 interlock with each other to grip a target object. Briefly, the gripping device 7 shown in FIG. 7 includes two coupled gripping assemblies (i.e., a first coupled gripping assembly 71 and a second coupled gripping assembly 72) that have similar configurations and are symmetrically arranged.

[0042] Taking the first connecting gripping assembly 71 as an example, it includes a fingertip 710, a first link 711 fixedly connected to the fingertip 710, and a second link 712 and a third link 713 each connected to the first link 711. A first end of the second link 712 is rotatably connected to a first end of the first link 711, and a second end of the second link 712 is rotatably connected to the case 70. A first end of the third link 713 is rotatably connected to a second end of the first link 711, and a second end of the third link 713 is rotatably connected to the case 70.

[0043] In one example, the rotation center of the first end of the second link 712, the rotation center of the second end of the second link 712, the rotation center of the second end of the third link 713, and the rotation center of the first end of the third link 713, in order, form four vertices of a quadrangle, thereby forming a four-link configuration. In another example, at least the second link 712 and the third link 713 are installed parallel to each other. In yet another example, the rotation center of the first end of the second link 712, the rotation center of the second end of the second link 712, the rotation center of the second end of the third link 713, and the rotation center of the first end of the third link 713, in order, form four vertices of a parallelogram, thereby forming a parallelogram link configuration.

[0044] The gripping device 7 further includes a drive assembly 30 that outputs a driving force in the axial direction and is operably connected to a second end of each second link to drive the second link to rotate, thereby realizing relative movement between the first linking gripping assembly 71 and the second linking gripping assembly 72.

[0045] Referring to FIG. 1 , in one example, the drive assembly 30 includes a motor 31, a lead screw 32, a nut 33, and a plurality of transmission members 34. The lead screw 32 is connected to an output end of the motor 31 and is driven by the motor 31 to rotate along its axial direction. The nut 33 is coupled to the lead screw 32 and moves along the axial direction of the lead screw 32 as the lead screw 32 rotates. The plurality of transmission members 34 correspond to each connecting gripper assembly, respectively. A first end of the transmission member 34 is rotatably connected to the nut 33, and a second end of the transmission member 34 is fixedly connected to a second end of the second link 712. When the motor 31 drives the lead screw 32 to rotate along the axial direction, the nut 33 rotates the second link 712. Based on this, the drive assembly 30 can output a driving force along the axial direction of the lead screw 32 by the motor 31.

[0046] Referring to the schematic diagram of the configuration of a link according to some embodiments of the present application shown in Fig. 8, a load cell 80 is embedded in the link along the axial direction to measure the axial force of the link. The link of Fig. 8 can be applied to the first link 711, the second link 712, or the third link 713 of the gripping device 7 according to the embodiments of the present application to measure the axial force of the link. It can be understood that the axial force refers to the internal axial force of the first link 711, the second link 712, and the third link 713.

[0047] The drive assembly 30 of the gripping device 7 may be provided with a load cell 80 for measuring the driving force output by the drive assembly 30 along the axial direction. In one example, referring to FIGS. 1 and 8, the load cell may be embedded axially within the lead screw 32 to measure the axial force of the lead screw when the gripping device 7 is in static equilibrium. In other examples, the drive assembly 30 may be provided with other force measuring assemblies, including those described in U.S. Patent No. 6,244,999, the contents of which are incorporated herein by reference, to measure the driving force output by the drive assembly 30 along the axial direction.

[0048] Below, we will introduce in detail an embodiment in which load cells are installed on at least three of the first link 711, the second link 712, the third link 713, and the drive assembly 30 (whose axial drive force corresponds to that of the fourth link) to realize a specific example of calculating force information output by the fingertip 710.

[0049] In the first example, axial force sensors are installed on the first link 711, the second link 712, and the third link 713, and in the gripping device 7 in a static equilibrium state, 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-mentioned 14 force / moment equilibrium equations are calculated by dividing the force normal force F output by the fingertip 710 by the force normal force F tip、x , tangential force F tip、y and bending moment M tip can be transformed into the following matrix equation to obtain

number

[0050] In the second example, axial force sensors are installed on the second link 712, the third link 713, and the drive assembly 30, and in the gripping device 7 in a static equilibrium state, 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, based on the above-mentioned 14 force / moment equilibrium equations, the force normal force F output by the fingertip 710 can be calculated as tip、x , tangential force F tip、y and bending moment M tip It is possible to obtain

[0051] In the third example, axial force sensors are installed on the first link 711, the third link 713, and the drive assembly 30, and in the gripping device 7 in a static equilibrium state, 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, based on the above-mentioned 14 force / moment equilibrium equations, the force normal force F output by the fingertip 710 can be calculated as tip、x , tangential force F tip、y and bending moment M tip It is possible to obtain

[0052] In the fourth example, axial force sensors are installed on the first link 711, the second link 712, and the drive assembly 30, and in the gripping device 7 in a static equilibrium state, 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, based on the above-mentioned 14 force / moment equilibrium equations, the force normal force F output by the fingertip 710 can be calculated as tip、x , tangential force F tip、y and bending moment M tip It is possible to obtain

[0053] Considering that equations (12) and (13) each relate to F3 in the force / moment equilibrium equation for the third link 713 described above, in a further embodiment, an axial force sensor is installed on the third link 713, and axial force sensors are installed on at least two of the first link 711, the second link 712, and the drive assembly 30. When the gripping device 7 is in a static equilibrium state, a force / moment equilibrium equation is constructed based on a static model, and the force values of the installed multiple axial force sensors are substituted into the force / moment equilibrium equation, whereby the force normal force F output by the fingertip 710 can be calculated. tip、x , tangential force F tip、y and bending moment M tip Ask for.

[0054] A multi-degree-of-freedom sensor 714 may be additionally installed in the gripping device 7. Referring to FIG. 7, the multi-degree-of-freedom sensor 714 can be installed on the fingertip 710 so as to directly measure the force information output by the fingertip 710. Based on this, the normal force F of the fingertip 710 calculated by the static model of the gripping device 7 as described above can be calculated. tip、x , tangential force F tip、y and bending moment M tip Furthermore, force information of other degrees of freedom of the fingertip 710 may also be measured by the multi-degree-of-freedom sensor 714, which contributes to monitoring the forces of other degrees of freedom output by the fingertip 710.

[0055] Based on the same technical concept as above, referring to FIG. 9 , some embodiments of the present invention further provide a robot, including the gripping device 7, a position measurement device, and a control system described in any of the above embodiments. The position measurement device measures structural parameters and position parameters of the first link 711, the second link 712, and the third link 713. The structural parameters include the lengths of the first link 711, the second link 712, and the third link 713, and the position parameters include the attitude vectors of the first link 711, the second link 712, and the third link 713. The control system acquires measurements from the position measurement device and multiple load cells when the gripping device 7 is in a static equilibrium state and calculates force information output by the fingertip 710 by constructing static models of the first link 711, the second link 712, the third link 713, and the drive assembly 30, respectively.

[0056] In one example, at least three load cells are installed in the gripping device 7 to measure at least three axial forces among the axial force F1 of the first link 711, the axial force F2 of the second link 712, the axial force F3 of the third link 713, and the axial force F4 of the drive assembly 30 based on the above force / moment balance equations (1)-(14). The position measuring device measures the angle parameters θ1, θ2, and the length parameter l tip , l1, l2, l4, Δl1, etc. When the gripping device 7 is in static equilibrium, the control system constructs force / moment equilibrium equations for each link of the gripping device 7, obtains measurements from multiple load cells and position measuring devices, and calculates the normal force F of the fingertip 710. tip、x , tangential force F tip、y and bending moment M tip Ask for.

[0057] For details of other configurations of the robot according to this embodiment, reference may be made to the relevant description of the above embodiment of the gripping device 7, but it can be understood that they will not be repeated here.

[0058] Based on the same technical idea as above, an embodiment of the present invention further provides a force information sensing method that can be applied to both the gripping device 7 and the robot. Referring to Fig. 10, the force information sensing method includes the following steps:

[0059] At S1, force measurements are taken from multiple load cells in the gripping device 7 in static equilibrium.

[0060] In one example, at least three load cells are installed in the gripping device 7, and when the gripping device 7 is in a static equilibrium state, the load cells acquire at least three axial forces from among the axial force F1 of the first link 711, the axial force F2 of the second link 712, the axial force F3 of the third link 713, and the axial force F4 of the fourth link.

[0061] In S2, the structural parameters and positional parameters of the first link, the second link, and the third link are measured.

[0062] In one example, when the gripping device 7 is in a static equilibrium state, parameters such as the angle θ1 between the longitudinal direction of the first link 711 and the horizontal direction, the angle θ2 between the longitudinal direction of the second link 712 and the horizontal direction, the length l1 of the first link 711, the length l2 of the second link 712, the length Δl1 of the connection line from the connection point between the first link 711 and the third link 713 to the connection point between the first link 711 and the fingertip 710, and the vertical distance l4 of the connection point between the second link 712 and the transmission member relative to the axial extension direction of the drive assembly 30 are obtained based on the position and posture of the coupled gripping assembly of the gripping device 7.

[0063] In S3, a static model of each of the first link, second link, third link, and drive assembly is constructed based on the force measurements taken in S1 and the structural and positional parameters measured in S2, and the force information output by the fingertip is calculated.

[0064] In one example, the first link 711, the second link 712, and the third link 713 in the gripping device 7 in a static equilibrium state are simplified into two-force links, and the drive assembly 30 and the second link 712 are simplified into a torque model. A static force analysis is performed for each model, and force / moment equilibrium equations for the planar force systems of the first link 711, the second link 712, the third link 713, and the drive assembly 30 are constructed, thereby determining the force normal force F output by the fingertip 710. tip、x , tangential force F tip、y and bending moment M tip Ask for.

[0065] For other details related to the implementation of the force information sensing method according to this embodiment, reference may be made to the relevant descriptions of the gripping device 7 and the robot embodiment, but it is understood that they will not be repeated here.

[0066] In light of the above, the gripping device, robot, and force information sensing method provided by the embodiments of the present invention provide a gripping device. By installing axial force sensors on the links and / or drive assemblies of the gripping device, force / moment equilibrium equations for the planar force system of the links and / or drive assemblies of the gripping device can be constructed when the gripping device is in a static equilibrium state, thereby calculating the force information output by the fingertips and monitoring the multi-degree-of-freedom force information output by the fingertips of the gripping device. Monitoring the multi-degree-of-freedom force information applied to an object by the fingertips contributes to maintaining a stable and accurate gripping force applied to an object by the gripping device, thereby improving the robustness and adaptability of the robot's gripping device.

[0067] Those skilled in the art will understand that implementing all or part of the steps of the above method embodiments can be achieved by instructing relevant hardware with a computer program, which is stored in a non-volatile computer-readable storage medium and, when executed, performs the steps of the above method embodiments. References to memory, storage, databases, or other media used in the embodiments provided herein include at least one of non-volatile memory and volatile memory. Non-volatile memory includes read-only memory (ROM), magnetic tape, floppy disks, flash memory, optical memory, etc. Volatile memory includes random access memory (RAM) or external cache memory. As a non-limiting example, RAM may take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0068] The technical features of the above-described embodiments can be combined in any manner. For the sake of brevity, not all combinations of the technical features in the above-described embodiments are described, but any combination of these technical features should be considered within the scope of the present specification unless there is a contradiction.

[0069] The above examples merely illustrate some embodiments of the present application, and although the descriptions are specific and detailed, they should not be construed as limiting the scope of protection of the invention. Those skilled in the art may make minor modifications and improvements without departing from the spirit of the present application, and all of these modifications and improvements are within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined in accordance with the claims. [Explanation of symbols]

[0070] 1,7 Grip device, 10,70 Case, 11,12,71,72 Coupled grip assembly, 30 Drive assembly, 31 Motor, 32 Lead screw, 33 Nut, 34 Transmission member, 80 Load cell, 110,710 Fingertip, 111,711 First link, 112,712 Second link, 113,713 Third link, 714 Multi-degree-of-freedom sensor

Claims

1. A gripping device, Case and A plurality of interlocking gripping assemblies adapted to interlock with one another to grip an object, each interlocking gripping assembly comprising: fingertips configured to grasp an object; a first link fixedly connected to the fingertip; a second link having a first end rotatably connected to the first end of the first link and a second end rotatably connected to the case; a third link having a first end rotatably connected to a second end of the first link and a second end rotatably connected to the case; and a drive assembly operably connected to a second end of the second link and configured to rotate the second link; a plurality of load cells, each of which is installed on at least three members of the first link, the second link, the third link, and the drive assembly, and configured to measure axial forces of the at least three members of the first link, the second link, the third link, and the drive assembly in the gripping device in a static equilibrium state, and calculate force information output by the fingertip.

2. 2. The gripping device according to claim 1, wherein at least the third link has one of the plurality of load cells embedded therein along its axial direction and configured to measure an axial force that is an internal axial force of the third link in the gripping device in a static equilibrium state.

3. The drive assembly includes: A motor; a lead screw connected to an output end of the motor and driven by the motor to rotate along its axial direction; a nut coupled to the lead screw and configured to move along the axial direction of the lead screw in response to rotation of the lead screw; 2. The gripping device of claim 1, comprising: a plurality of transmission members, each corresponding to a respective one of the coupled gripping assemblies, a first end of the transmission member rotatably connected to the nut, a second end of the transmission member fixedly connected to a second end of the second link, the nut configured to rotate the second link in response to the motor rotating the lead screw along the axial direction.

4. 4. The gripping device of claim 3, wherein the drive assembly is provided with one of the plurality of load cells, the load cell being configured to measure a drive force output by the drive assembly along an axial direction of the lead screw.

5. 2. The gripping device according to claim 1, wherein each of the plurality of load cells is embedded axially in each of the first link, the second link, and the third link and configured to measure an axial force that is an internal axial force of each of the first link, the second link, and the third link in the gripping device in a static equilibrium state.

6. The gripping device according to claim 1 , wherein the force information includes a tangential force, a normal force, and a bending moment along a contact surface of the fingertip.

7. The gripping device according to claim 1 , wherein the fingertip further includes a multi-degree-of-freedom sensor that measures force information of the fingertip when the fingertip grips an object.

8. A robot, The gripping device according to any one of claims 1 to 7, The robot further comprises: a position measurement device configured to measure structural parameters and position parameters of the first link, the second link, and the third link, wherein the structural parameters include lengths of the first link, the second link, and the third link, and the position parameters include attitude vectors of the first link, the second link, and the third link; a control system configured to acquire measurement values from the position measurement device and the plurality of load cells when the gripping device is in a static equilibrium state, construct a static model of each of the first link, the second link, the third link, and the drive assembly, and calculate force information output by fingertips.

9. 10. A method for sensing force information applied to a gripping device according to claim 1, comprising: obtaining force measurements from the plurality of load cells while the gripping device is in static equilibrium; measuring structural and positional parameters of the first link, the second link, and the third link; constructing a static model of each of the first link, the second link, the third link, and the drive assembly based on the force measurement values, the structural parameters, and the position parameters, and calculating force information output by a fingertip.

10. constructing a static model of each of the first link, the second link, the third link, and the drive assembly based on the force measurements, the structural parameters, and the position parameters, comprising: simplifying the first link, the second link, and the third link into two force members, and simplifying the drive assembly and the second link together into a moment balance model; performing a static force analysis on the two force members and the moment balance model; and building a static model of each of the first link, the second link, the third link, and the drive assembly.

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