Gripping 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 robot technology, and particularly to a gripping device, a robot having the gripping device, and a force information sensing method applied to the gripping device.

Background Art

[0002] The gripping device is an important end-execution mechanism in a robot. The gripping device is usually driven by a drive assembly, and the gripping or releasing of an object is realized by its fingertip portion. When the gripping device grips an object, particularly a fragile object, it is necessary to appropriately and stably maintain the acting force applied from the fingertip portion to the object. Therefore, the monitoring of the force information output by the fingertip portion to the object is very important.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The first aspect of the embodiment of the present invention provides a gripping device, including a case, a plurality of connected gripping assemblies that cooperate with each other to grip an object, and a driving assembly. Each connected gripping assembly includes a fingertip portion configured to grip the object, a first link, a second link, and a third link. The first link is fixedly connected to the fingertip portion. 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 driving assembly is transmission-connected to the second end of the second link to rotate the second link. The gripping device further includes a plurality of load cells, which are respectively installed on at least three of the first link, the second link, the third link, and the driving assembly, and are configured to measure the axial forces of at least three members of the gripping device in a static equilibrium state to calculate the force information output by the fingertip portion.

[0005] The second aspect of the embodiment of the present invention provides a robot, which includes any one of the gripping devices described above, a position measuring device, and a control system. The position measuring device measures the structural parameters and position parameters of the first link, the second link, and the third link. The structural parameters include the lengths 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 acquires the measurement values of the position measuring device and the measurement values of the plurality of load cells when the gripping device is in a static equilibrium state, constructs the respective static models of the first link, the second link, the third link, and the driving assembly, and calculates the force information output by the fingertip portion.

[0006] A third aspect of the embodiments of the present invention provides a method for sensing force information of a gripping device applicable to any of the gripping devices described above, the method comprising: acquiring force measurements of a plurality of load cells when the gripping device is in a static equilibrium state; measuring structural and positional parameters of a first link, a second link, and a third link; constructing a static model of the first link, the second link, the third link, and the drive assembly based on the force measurements, structural parameters, and positional parameters, and calculating force information output by the fingertip portion.

[0007] Details of one or more embodiments of the present invention are described in the drawings and description below. Other features, purposes and advantages of the present invention will become apparent from the specification, drawings and claims.

[0008] To more clearly explain the technical embodiments of the present invention, the drawings to be used in describing the embodiments are briefly described below. However, the drawings described below represent only a few embodiments of the present invention and do not limit the disclosure and scope of protection of the present invention. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of the configuration of a gripping device according to one exemplary embodiment of the present invention. [Figure 2] Figure 1 is a schematic diagram of the link model of the gripping device configuration. [Figure 3] Figure 2 shows the force diagram of the first link and fingertip portion of the gripping device. [Figure 4] This is a force diagram of the second link of the gripping device in Figure 2. [Figure 5] This is a force diagram of the third link of the gripping device in Figure 2. [Figure 6] Figure 2 shows the moment diagrams of the fourth and second links of the gripping device. [Figure 7] This is a schematic diagram of the configuration of a gripping device according to one embodiment of the present invention. [Figure 8] This is a schematic diagram of a part of the 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] This is a schematic diagram of a robot according to one embodiment of the present invention. [Figure 10] This is a flowchart of a force information sensing method for a gripping device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] To further clarify the above-mentioned objectives, features, and advantages of the present invention, specific embodiments of the present invention will be described in detail below with reference to the drawings. While specific details are provided below to ensure a full understanding of the present invention, the present invention can be implemented in embodiments different from those described herein and can be improved by those skilled in the art without departing from the spirit of the invention; therefore, the present invention is not limited to the following specific embodiments.

[0011] In the description of the present invention, terms such as "center," "vertical," "horizontal," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate orientations or positional relationships based on those shown in the accompanying drawings, and are merely for the purpose of facilitating and simplifying the description of the present invention. They are not intended to express or imply that any device or element mentioned has a particular orientation, is configured in a particular orientation, or must be operated in a particular orientation, and therefore should not be construed as limitations of the present invention.

[0012] In the present invention, unless otherwise specifically defined and limited, terms such as "attached," "contact," "connected," "fixed," and "installed" should be understood in a broad sense. For example, unless otherwise specifically defined, "connection" may be a fixed connection, a detachable connection or an integrated connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, a relationship of communication between two elements, or an interaction relationship between two elements. For example, when one 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. To those skilled in the art, the specific meaning of the above terms in the present invention can be understood from the specific context.

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

[0014] In the first measurement method, a tactile sensor is directly installed on the fingertip of the gripping device, and the force applied by the fingertip to the object when the fingertip grips the object is directly measured by the tactile sensor. However, existing tactile sensors may not yet be able to reliably and accurately acquire multi-degree-of-freedom force feedback information, and therefore this method has not yet been widely applied in this field.

[0015] In the second measurement method, considering that the gripping device is usually driven by a motor and that the motor's driving torque is related to the motor's current, it is possible to obtain torque information by monitoring the motor's current. However, because the motor's current is susceptible to 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 that the gripping device applies to the object.

[0016] On the other hand, as robotic gripping devices are increasingly applied to complex gripping tasks, especially those involving fragile objects, it becomes crucial to monitor and maintain that the fingertips of the gripping device provide stable and accurate gripping force.

[0017] The present invention relates to an improved technology that calculates the force output by the fingertip portion of a robotic gripping device based on the force and / or moment equilibrium principle when the robotic gripping device is in a static equilibrium state.

[0018] The concept of the present invention will be explained below, first with reference to the example gripping device shown in Figure 1.

[0019] Referring to Figure 1, the illustrated gripping device 1 includes a case 10, a first quadrilateral coupling gripping assembly 11 attached to the case 10, a second quadrilateral coupling gripping assembly 12, and a drive assembly 30. The first quadrilateral coupling gripping assembly 11 and the second quadrilateral coupling gripping assembly 12 have similar configurations and are installed symmetrically. The drive assembly 30 enables the gripping device 1 to grip or release an object by driving the first quadrilateral coupling gripping assembly 11 and the second quadrilateral coupling gripping assembly 12, respectively.

[0020] Taking the first quadrilateral linking gripping assembly 11 as an example, it includes a fingertip portion 110, a first link 111 fixedly connected to the fingertip portion 110, and a second link 112 and a third link 113, respectively, connected to the first link 111. The first end of the second link 112 is rotatably connected to the first end of the first link 111, and the second end of the second link 112 is rotatably connected to the case 10. The first end of the third link 113 is rotatably connected to the second end of the first link 111, and the 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 configuration, the rotation of the lead screw 32 drives the nut 33 to move along the lead screw 32, and the transmission member 34 further rotates the second link 112, 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 realizing the movement of the fingertip portion 110. In other embodiments, the drive assembly 30 may be driven to move the third link 113, causing the first link 111 and the second link 112 to follow the movement of the third link 113, and the force information sensing method disclosed herein is similarly applicable to the above scenario, even if the calculation process differs slightly.

[0021] Figure 2 is a schematic diagram of the link model of the gripping device 1 of Figure 1, taking the first quadrilateral linked gripping assembly 11 as an example, and showing a fingertip portion 110, a first link 111 fixedly connected to the fingertip portion 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 along the axial direction of the lead screw by the drive assembly. The fourth link 114 is connected to the second link 112 by a transmission member 34, and rotational torque is applied to the second link 112.

[0022] This application is applicable when the gripping device 1 grips an object and is in a static equilibrium state. Referring to FIGS. 3 to 6, the force analysis of the fingertip portion 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] FIG. 3 shows a force indication diagram of the fingertip portion 110 and the first link 111 of the gripping device 1. The fingertip portion 110 is fixedly connected to the first link 111, and the whole is taken as the object of study. When the fingertip portion 110 and the first link 111 are in a static equilibrium state, the force / moment equilibrium equations of its planar force system are as follows.

Equation

[0024] F 21、x is the horizontal component force of the second link 112 with respect to the first link 111, and F 21、y is the vertical component force of the second link 112 with respect to the first link 111, and F 31、x is the horizontal component force of the third link 113 with respect to the first link 111, and F 31、y is the vertical component force of the third link 113 with respect to the first link 111, and F tip、x is the normal force of the fingertip portion 110 on the object, and F tip、y is the tangential force of the fingertip portion 110 on the object, and M tip is the bending moment of the fingertip portion 110, F1 is the axial force of the first link 111, and l tip is the length of the fingertip portion 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 portion 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 force analysis of the first link 111 and the fingertip portion 110 described above, there are a total of 4 equations and 9 unknowns, namely, F 21、x , F 21、y , F31、x F 31、y F tip、x F tip、y M tip , including F1 and θ1. In the above equation, l tip Since l1 is a structural parameter of the fingertip portion 110, l1 is a structural parameter of the first link 111, and Δl1 can relate to the structural parameters of the first link 111 and the third link 113, l tip Therefore, l1 and Δl1 can be considered known quantities.

[0026] Figure 4 shows the force diagram of the second link 112 of the gripping device 1. The second link 112 is the subject of consideration, and since the second link 112 is in a state of static equilibrium, the force / moment equilibrium equation for its plane force system is as follows.

number

[0027] F 12、x F is the horizontal component force of the first link 111 relative to the second link 112. 42、x This is the horizontal component force of the fourth link 114 relative to the second link 112, and F 12、y F is the vertical component force of the first link 111 relative to the second link 112. 42、y This is the vertical component force of the fourth link 114 relative to the second link 112, and M 24 θ2 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 and horizontal directions 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 This means that they are equal in size and opposite in direction, F 12、y and F 21、y These are two things that are equal in size but move in opposite directions.

[0029] In the force analysis for the second link 112, there are a total of four equations and four unknowns, namely F42、x F 42、y This includes θ2 and F2. In the above equation, since l2 is the structural parameter of the second link 112, 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 Figure 5, and considering the third link 113 as the subject of study, since the third link 113 is in a static equilibrium state, the force / moment equilibrium equation for its plane force system is as follows.

number

[0031] F 13、x This is the horizontal component force of the first link 111 relative to the third link 113, and F 03、x This is the horizontal component force of case 10 relative to the third link 113, and F 13、y F is the vertical component force of the first link 111 relative to the third link 113. 03、y F3 is the vertical component force of 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 F 31、x This means that they are equal in size and opposite in direction, F 13、y and F 31、y These are two things that are equal in size but move in opposite directions.

[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 of the gripping device 1 between the fourth link 114 and the second link 112 shown in Figure 6, and considering the fourth link 114 as the subject of consideration, and given that the drive assembly 30 is in a static equilibrium state, the torque equation for its plane force system is as follows.

number

[0035] M 42 F4 is the torque acting on the second link 112 by the fourth link 114, l4 is the perpendicular distance between the connection point of the second link 112 and the transmission member 34 with respect to the extending direction of the fourth link 114, and F4 is the axial driving force of the fourth link 114. 42 and the aforementioned M 24 These are two things that are equal in size but move in opposite directions.

[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, since l4 is a structural parameter between the second link 112 and the fourth link 114, l4 can be considered a known quantity.

[0037] Based on the above, when the gripping device 1 is in a static equilibrium state, the force / moment equilibrium equations for the equivalent four-link plane force system relate to a total of 18 unknowns and 14 equations. Of these 18 unknowns, angles θ1 and θ2 relate to the position and orientation of the first link 111, the second link 112, and the third link 113 in a static state, and can be obtained, for example, by the position encoder of the motor 31 and the orientation measuring device of the links. Therefore, equations (1)-(14) above contain a total of 16 unknowns. Theoretically, to reduce the number of unknowns to 14, it would be sufficient to add the measurement of two unknowns. However, considering that there are two equations using parameter F3 in the force analysis of the third link 113, it is necessary to measure three unknowns to reduce the number of unknowns to 13. Thus, based on the 14 equations, the force information output by the fingertip portion 110, for example, the normal force F tip、x , tangential force F tip、y and bending moment M tip It is possible to find this.

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

[0039] To realize the concept of the above invention, a subset of embodiments of the present application provides a gripping device comprising a case, a plurality of linked gripping assemblies that combine with each other to grip an object, and a drive assembly, each linked gripping assembly comprising a fingertip portion configured to grip an object, a first link, a second link, and a third link. The first link is fixedly connected to the fingertip portion. The second link has its first end rotatably connected to the first end of the first link and its second end rotatably connected to the case. The third link has its first end rotatably connected to the second end of the first link and its second end rotatably connected to the case. The drive assembly is dynamally connected to the second end of the second link and rotates the second link. The gripping device further includes a plurality of load cells, each of which is installed on at least three of the components of the first link, second link, third link, and drive assembly, and is configured to measure the axial force of at least three components of the gripping device in a static equilibrium state and calculate force information output by the fingertip portion. This force information includes the tangential force, normal force, and bending moment of the fingertip portion along the contact surface.

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

[0041] Referring to Figure 7, some embodiments of the present invention provide a gripping device 7 comprising a case 70 and a first coupling gripping assembly 71 and a second coupling gripping assembly 72 attached to the case 70. In other embodiments, the gripping device 7 may include more coupling gripping assemblies, for example, three or more coupling gripping assemblies. Two or more coupling gripping assemblies in the gripping device 7 combine with each other to grip a target object. Briefly described in this application, the gripping device 7 shown in Figure 7 includes two coupling gripping assemblies (i.e., a first coupling gripping assembly 71 and a second coupling gripping assembly 72) having similar configurations and being symmetrically arranged.

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

[0043] In one example, the pivot centers of the first end of the second link 712, the pivot center of the second end of the second link 712, the pivot center of the second end of the third link 713, and the pivot center of the first end of the third link 713 sequentially form the four vertices of a quadrilateral, thus 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 pivot centers of the first end of the second link 712, the pivot center of the second end of the second link 712, the pivot center of the second end of the third link 713, and the pivot center of the first end of the third link 713 sequentially form the four vertices of a parallelogram, thus 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. The drive assembly is ductilely connected to the second end of each second link to drive the second link to rotate, thereby enabling relative movement between the first coupling gripping assembly 71 and the second coupling gripping assembly 72.

[0045] Referring to Figure 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 the output terminal of the motor 31 and is driven by the motor 31 to rotate along the axial direction. The nut 33 is coupled to the lead screw 32 and moves along the axial direction of the lead screw 32 in response to the rotation of the lead screw 32. The plurality of transmission members 34 correspond to each coupling gripping assembly, with the first end of each transmission member 34 rotatably connected to the nut 33 and the second end of each transmission member 34 fixedly connected to the second end of a second link 712, so that when the motor 31 is driven to rotate the lead screw 32 along the axial direction, the nut 33 rotates the second link 712. Based on this, the drive assembly 30 is able to 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 link configuration according to a partial embodiment of the present application shown in Figure 8, a load cell 80 is embedded in the link along the axial direction to measure the axial force of the link. The link in Figure 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 an embodiment of the present application to measure the axial force of the link. It can be understood that the axial force is 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 equipped with a load cell 80 for measuring the driving force output axially by the drive assembly 30. In one example, referring to Figures 1 and 8, the load cell may be embedded in the lead screw 32 axially to measure the axial force of the lead screw when the gripping device 7 is in a static equilibrium state. In another example, the drive assembly 30 may be equipped with a force measuring assembly, in other forms including, for example, the form described in Patent Document 1, for measuring the driving force output axially by the drive assembly 30, the contents of which are incorporated into this application by reference.

[0048] The following describes 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 (the axial drive force of which corresponds to the fourth link) in order to realize a specific embodiment for calculating force information output by the fingertip portion 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. In the gripping device 7 in a static equilibrium state, the axial force sensor on the first link 711 measures the axial force F1, the axial force sensor on the second link 712 measures the axial force F2, and the axial force sensor on the third link 713 measures the axial force F3. The 14 force / moment equilibrium equations described above are based on the force normal force F output by the fingertip portion 710. tip、x , tangential force F tip、y and bending moment M tip It is possible to transform this into the following matrix equation in order to find the value.

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. In the gripping device 7 in a static equilibrium state, the axial force sensor on the second link 712 measures the axial force F2, the axial force sensor on the third link 713 measures the axial force F3, and the axial force sensor on the drive assembly 30 measures the axial force F4. Similarly, based on the 14 force / moment equilibrium equations described above, the force normal force F output by the fingertip portion 710 is measured. tip、x , tangential force F tip、y and bending moment M tip It is possible to find this.

[0051] In the third example, axial force sensors are installed on the first link 711, the third link 713, and the drive assembly 30. In the gripping device 7 in a static equilibrium state, the axial force sensor on the first link 711 measures the axial force F1, the axial force sensor on the third link 713 measures the axial force F3, and the axial force sensor on the drive assembly 30 measures the axial force F4. Similarly, based on the 14 force / moment equilibrium equations described above, the force normal force F output by the fingertip portion 710 is measured. tip、x , tangential force F tip、y and bending moment M tip It is possible to find this.

[0052] In the fourth example, axial force sensors are installed on the first link 711, the second link 712, and the drive assembly 30. In the gripping device 7 in a static equilibrium state, the axial force sensor on the first link 711 measures the axial force F1, the axial force sensor on the second link 712 measures the axial force F2, and the axial force sensor on the drive assembly 30 measures the axial force F4. Similarly, based on the 14 force / moment equilibrium equations described above, the force normal force F output by the fingertip portion 710 is measured. tip、x , tangential force F tip、y and bending moment M tip It is possible to find this.

[0053] In the force / moment equilibrium equation for the third link 713 described above, considering equations (12) and (13) to be related to F3, 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 hydrostatic model, and the force values ​​of the installed axial force sensors are substituted into the force / moment equilibrium equation to determine the force normal force F output by the fingertip portion 710. tip、x , tangential force F tip、y and bending moment M tip We seek.

[0054] A multi-degree-of-freedom sensor 714 may be additionally installed on the gripping device 7. Referring to Figure 7, it is possible to install the multi-degree-of-freedom sensor 714 on the fingertip portion 710 to directly measure the force information output by the fingertip portion 710. Based on this, the normal force F of the fingertip portion 710 obtained by the static model of the gripping device 7 as described above can be measured. tip、x , tangential force F tip、y and bending moment M tip Furthermore, force information from other degrees of freedom of the fingertip portion 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 portion 710.

[0055] Based on the same technical concept as described above, and with reference to Figure 9, some embodiments of the present invention further provide a robot which includes a gripping device 7, a position measuring device, and a control system as described in any of the embodiments described above. The position measuring device measures the structural and positional 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 positional parameters include the attitude vectors of the first link 711, the second link 712, and the third link 713. The control system calculates force information output by the fingertip portion 710 by acquiring measurements from the position measuring device and a plurality of load cells when the gripping device 7 is in a static equilibrium state, and 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, the gripping device 7 is equipped with at least three load cells to measure 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 drive assembly 30, based on the force / moment equilibrium equations (1)-(14) above. The position measuring device has angle parameters θ1, θ2 and length parameter l tip The structural and positional parameters of the first link 711, the second link 712, and the third link 713 are measured to obtain l1, l2, l4, Δl1, etc. When the gripping device 7 is in a static equilibrium state, 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 measures the normal force F of the fingertip portion 710. tip、x , tangential force F tip、y and bending moment M tip We seek.

[0057] Details of other components of the robot according to this embodiment can be found in the relevant description of the gripping device 7 in the above embodiment, but it is understandable that this will not be repeated here.

[0058] Based on the same technical concept as described above, embodiments of the present invention further provide a force information sensing method that can be applied to either the gripping device 7 or the robot described above. Referring to Figure 10, the force information sensing method includes the following steps.

[0059] In S1, force measurements of multiple load cells in the gripping device 7, which is in a static equilibrium state, are obtained.

[0060] In one example, the gripping device 7 is equipped with at least three load cells, and when the gripping device 7 is in a static equilibrium state, the load cells acquire at least three of the following axial forces: 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 and positional parameters of the first, second, and third links 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 and horizontal directions of the first link 711, the angle θ2 between the longitudinal and horizontal directions 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 connecting 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 portion 710, and the vertical distance l4 of the connection point between the second link 712 and the transmission member with respect to the axial extension direction of the drive assembly 30 are obtained based on the position and orientation of the linked gripping assembly of the gripping device 7.

[0063] In S3, based on the force measurements taken in S1 and the structural and positional parameters measured in S2, static models are constructed for the first link, second link, third link, and drive assembly, 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, which is in a static equilibrium state, are simplified to a two-force link, and the drive assembly 30 and the second link 712 are simplified to a torque model. Static force analysis is performed on each model, and the force / moment equilibrium equations for the plane 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 portion 710. tip、x , tangential force F tip、y and bending moment M tip We seek.

[0065] Further details relating to the implementation of the force information sensing method according to this embodiment may be found in the relevant descriptions relating to the gripping device 7 and robot embodiment, but it is understandable that they are not repeated here.

[0066] Based on the above, by installing axial force sensors on the links and / or drive assemblies of the gripping device, based on the gripping device, robot, and force information sensing method provided in the embodiment of the present invention, when the gripping device is in a static equilibrium state, force information output by the fingertips can be calculated by constructing the force / moment equilibrium equation of the plane force system of the links and / or drive assemblies of the gripping device, and multi-degree-of-freedom force information output from the fingertips of the gripping device can be monitored. By monitoring the multi-degree-of-freedom force information that the fingertips apply to an object, it is possible to maintain a stable and accurate gripping force applied by the gripping device to an object, thereby improving the robustness and adaptability of the robot's gripping device.

[0067] Those skilled in the art will understand that all or part of the steps relating to the embodiments of the above methods can be achieved by instructing the relevant hardware with a computer program, wherein the computer program is stored on a non-volatile computer-readable storage medium, and when the computer program is executed, the steps of the embodiments including each of the above methods are performed. References to memory, storage, database, or other media used in each embodiment provided herein all include at least one of non-volatile memory and volatile memory. Non-volatile memory includes read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical memory. Volatile memory includes random access memory (RAM) or external cache memory. In a non-limiting description, RAM may take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0068] The technical features of the embodiments described above can be combined in any way. For the sake of brevity, not all combinations of the technical features in the embodiments described above have been explained, but these combinations of technical features should be considered to fall within the scope described herein, as long as they are not contradictory.

[0069] The embodiments described above are merely examples of some embodiments of the present application, and although their descriptions are specific and detailed, they should not be interpreted as limiting the scope of protection of the invention. Furthermore, a person skilled in the art can make some modifications and improvements as long as they do not deviate from the spirit of the present application, and these too fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be the same as that of the claims. [Explanation of Symbols]

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

Claims

1. A gripping device, The case and, A plurality of interconnected gripping assemblies that are combined with each other to grip an object, each interconnected gripping assembly is A fingertip portion configured to grasp an object, The first link is fixedly connected to the fingertip portion, A second link, the first end of which is rotatably connected to the first end of the first link, and the second end of which is rotatably connected to the case, A plurality of connecting gripping assemblies, including a third link whose first end is rotatably connected to the second end of the first link and whose second end is rotatably connected to the case, A drive assembly is scalably connected to the second end of the second link and configured to rotate the second link, A gripping device comprising: a plurality of load cells, each load cell being installed on at least three of the first link, second link, third link, and drive assembly, and configured to measure the axial force of at least three of the first link, second link, third link, and drive assembly in the gripping device in a static equilibrium state, and to calculate force information output by the fingertip portion.

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

3. The aforementioned drive assembly is Motor and, A lead screw connected to the output terminal of the motor and driven by the motor to rotate axially, A nut connected to the lead screw and configured to move along the axial direction of the lead screw in response to the rotation of the lead screw, A gripping device according to claim 1, comprising a plurality of transmission members, each corresponding to a connecting gripping assembly, the first end of each transmission member being rotatably connected to a nut, the second end of each transmission member being fixedly connected to the second end of a second link, and the nut being configured to rotate the second link in response to the motor rotating the lead screw along the axial direction.

4. The gripping device according to claim 3, wherein one of the plurality of load cells is installed in the drive assembly, and the load cell is configured to measure the driving force output by the drive assembly along the axial direction of the lead screw.

5. 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 is configured to measure the axial force, which is the internal axial force, of each of the first link, the second link, and the third link in the gripping device in a state of static equilibrium.

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

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

8. It is a robot, Includes a gripping device according to any one of claims 1 to 7, The robot further, A position measuring device for measuring the structural parameters and positional parameters of the first link, the second link, and the third link, wherein the structural parameters include the lengths of the first link, the second link, and the third link, and the positional parameters include the attitude vectors of the first link, the second link, and the third link. A robot comprising a control system configured to acquire measurement values ​​from the position measuring device and the plurality of load cells when the gripping device is in a static equilibrium state, construct static models of the first link, the second link, the third link and the drive assembly, and calculate force information output by the fingertip portion.

9. A method for sensing force information applied to a gripping device described in claim 1, The steps include: acquiring force measurements of the plurality of load cells while the gripping device is in a static equilibrium state; The steps include measuring the structural parameters and positional parameters of the first link, the second link, and the third link, A method for sensing force information, comprising the steps of constructing static models 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 the fingertip portion.

10. The step of constructing a static model of the first link, the second link, the third link, and the drive assembly based on the aforementioned force measurements, structural parameters, and position parameters is: The steps include 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 equilibrium model, The steps include performing a static force analysis on the two force members and the moment equilibrium model, The method according to claim 9, comprising the step of constructing a static model of the first link, the second link, the third link, and the drive assembly, respectively.

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