Deflection amount estimation device, robot control device, and deflection amount estimation method

Abstract

A deflection amount estimation device is provided with: an opening angle calculation unit (25) that calculates an opening angle (theta); the opening angle (theta) is the angle formed by one connecting rod (31) of the connecting rod structure part which rotates around a reference shaft which is the shaft of one rotating pair of the two-degree-of-freedom connecting rod structure part (11) with a plurality of rotating pairs and the other connecting rod (32) of the connecting rod structure part (11) which rotates around the reference shaft; a load calculation unit (26) that calculates the load received by the link structure unit (11); a stiffness matrix specifying unit (27) that specifies a stiffness value corresponding to the opening angle (theta) by using a stiffness value specifying function representing the correlation between the stiffness value and the opening angle (theta), the stiffness value being the value of each component of the stiffness matrix that associates the load with the deflection amount (delta); and a deflection amount calculation unit (28) that calculates the deflection amount (delta) of the link structure unit (11) on the basis of the load and the stiffness matrix having the stiffness value determined by the stiffness matrix determination unit (27) among the components.

Description

Technical Field

[0001] The present invention relates to a deflection amount estimating device, a robot control device, and a deflection amount estimating method. Background Art

[0002] Conventionally, for example, Patent Document 1 proposes a deflection amount estimation device for calculating the deflection amount of a link structure in a robot arm including a link structure. The deflection amount estimation device of Patent Document 1 calculates the estimated deflection amount based on the swing angle of the four-link structure. Thus, the deflection amount of the four-link structure can be estimated quickly, and further, speed-up for reducing cycle time and lightening of the links of the arm can be achieved.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-195892 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, the deflection amount estimation device described in Patent Document 1 estimates the deflection amount of the link structure part that can determine the movement of the link structure part based on the posture of one link. Therefore, the deflection amount estimation device described in Patent Document 1 cannot be applied to a two-degree-of-freedom link structure in which the movement of the link structure part cannot be determined by the posture of one link, and there is a limit in coping with high speed and lightweight of the link of the arm.

[0008] Technical solutions to solve problems

[0009] In order to solve the above-mentioned problems, a deflection amount estimation device in one embodiment of the present invention is a deflection amount estimation device for estimating the deflection amount of a link structure of a robot arm formed by connecting a plurality of links including a link structure with two degrees of freedom having a plurality of revolute pairs through joints, and comprising: an opening angle calculation unit, which calculates an opening angle (opening angle), wherein the opening angle is an angle formed by one link of the link structure part rotating around a reference axis which is an axis of a revolute pair of the link structure part and another link of the link structure part rotating around the reference axis; a load calculation part which calculates the load on the link structure part; a stiffness matrix determination part which determines the stiffness value corresponding to the opening angle of the link structure part calculated by the opening angle calculation part by using a stiffness value determination function which represents the correlation between the stiffness value and the opening angle of the link structure part, the stiffness value being the value of each component of the stiffness matrix which associates the load on the link structure part with the deflection amount of the link structure part; and a deflection amount calculation part which calculates the deflection amount of the link structure part based on the load on the link structure part calculated by the load calculation part and the stiffness matrix having the stiffness value determined by the stiffness matrix determination part in the component.

[0010] According to the above structure, the deflection amount of the link structure part with two degrees of freedom can be estimated. In addition, since the link structure part can have multiple degrees of freedom, the structure of the distal end side of the link structure part of the robot arm can be simplified. Furthermore, by using a stiffness matrix having stiffness values ​​determined according to the opening angle in the component, the deflection amount of the link structure part can be quickly estimated. Therefore, the amount of calculation in the process of calculating the deflection amount can be reduced, and the deflection amount can be quickly calculated.

[0011] Effects of the Invention

[0012] The present invention has an effect of being able to estimate the deflection amount of a link structure having two degrees of freedom. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a diagram showing a configuration example of a robot system including a deflection amount estimating device according to an embodiment.

[0014] Figure 2 It is schematically indicated Figure 1 A diagram of a structural example of a robot main body of a robot system.

[0015] Figure 3 It is schematically indicated Figure 1 The figure is a diagram of an example of the operation of the robot main body of the robot system, and is a diagram showing the rotation operation of the first driving link.

[0016] Figure 4It is schematically indicated Figure 1 The figure is a diagram of an example of the operation of the robot main body of the robot system, and is a diagram showing the rotation operation of the first driving link.

[0017] Figure 5 It roughly indicates Figure 1 A block diagram of an example structure of a control system of a robot system.

[0018] Figure 6 It means Figure 1 A flowchart of an operation example related to the deflection estimation operation of the robot system.

[0019] Figure 7 It means used for Figure 1 A diagram showing an example of a stiffness value determination function for a deflection estimation operation of a robot system.

[0020] Figure 8 It means used for Figure 1 A diagram showing an example of a stiffness value determination function for a deflection estimation operation of a robot system.

[0021] Fig. 9 Yes means Figure 2 A diagram showing a modified example of the robot body shown. DETAILED DESCRIPTION

[0022] Below, the embodiment is described with reference to the accompanying drawings. In addition, the present invention is not limited to the present embodiment. In addition, below, in all figures, the same reference symbols are marked for the same or equivalent elements, and their repeated descriptions are omitted. The functions of the elements disclosed in this specification can be performed using circuits or processing circuits, and the circuits or processing circuits include general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits and / or combinations thereof configured or programmed to perform the disclosed functions. Since the processor includes transistors or other circuits, it is regarded as a processing circuit or circuit. In the present disclosure, a circuit, a unit or a device is hardware that performs the listed functions, or hardware that is programmed to perform the listed functions. The hardware may be hardware disclosed in this specification, or may be other known hardware that is configured or programmed to perform the functions cited. If the hardware is a processor that is considered to be a kind of circuit, the circuit, device or unit is a combination of hardware and software, and the software is used for the structure of the hardware and / or processor.

[0023] Figure 1 1 is a diagram showing a configuration example of a robot system 100 including a deflection amount estimation device according to an embodiment. Figure 1 As shown, the robot system 100 includes a robot body 1 and a robot controller 2 .

[0024] [Example of the structure of the robot body]

[0025] Figure 2 Schematically shows a structural example of the robot body 1. Figure 2 As shown, the robot body 1 is a multi-jointed industrial robot. In addition, the robot body 1 is a robot of a five-link structure using a closed-loop structure in a lower arm structure supporting an upper arm structure 12 and a hand 8 described later, and has high mechanical rigidity, and can achieve stable operation under high load conditions.

[0026] The robot body 1 includes a base 6, a robot arm 7, and a hand 8. The base is fixedly placed on the ground, for example, and supports the robot arm 7 and the hand 8.

[0027] The robot arm 7 has a structure in which a plurality of links are connected by joints. The robot arm 7 includes a lower arm structure, an upper arm structure 12, a joint drive unit 13 and a lower arm first drive unit 14. The lower arm structure is also referred to as a link structure unit 11, which is rotatably connected relative to the base 6, for example, around a rotation axis extending in the up-down direction. The structure connecting the base 6 and the link structure unit 11 is a first joint axis JT1. In addition, the link structure unit 11 has a second joint axis JT2 and a third joint axis JT3. The upper arm structure 12 is continuously arranged with the link structure unit 11. Furthermore, the upper arm structure 12 has a fourth joint axis JT4, a fifth joint axis JT5 and a sixth joint axis JT6. Therefore, the robot arm 7 as a whole has 6 joint axes. Among the six joint axes, the four joint axes other than the link structure unit 11 are driven by the joint drive unit 13 corresponding to each joint, so that the link on the distal side rotates around the rotation axis relative to the link on the proximal side. In addition, the link structure 11 is driven by the lower arm first drive unit 14 and the lower arm second drive unit 15. The upper arm structure 12 is a serial structure, and is constructed in the same manner as the upper arm structure of a known vertical multi-joint type 6-axis robot, so a detailed description is omitted. In addition, in this specification, the term distal side refers to the hand 8 side in the direction in which the robot arm 7 extends, and the term proximal side refers to the base 6 side.

[0028] The link structure 11 is a link structure including a supporting link 30, a first driving link 31, a second driving link 32, a first driven link 33, a second driven link 34, a first driving shaft 35, a second driving shaft 36, a first connecting shaft 37, a second connecting shaft 38, and a third connecting shaft 39. The supporting link 30 is connected to the base 6 via a bearing and is rotatably connected to the base 6 around the rotation axis. In the basic posture of the robot body 1, the first driving link 31 and the first driven link 33 extend in the up-down direction, and the second driving link 32 and the second driven link 34 extend in the front-back direction. The supporting link 30, the first driving link 31, the second driving link 32, the first driven link 33 and the second driven link 34 respectively have a first part and a second part. In addition, in the first driving link 31, the second driving link 32, the first driven link 33 and the second driven link 34, the first part is one end and the second part is the other end. The second follower link 34 is integrally formed with and continuous with the proximal end portion of the upper arm structure 12 .

[0029] The first drive shaft 35 is supported on the support link 30 via a bearing, and is fixed to the first portion of the first drive link 31, connecting the first portion of the support link 30 and the first portion of the first drive link 31. The second drive shaft 36 is coaxially arranged with the first drive shaft 35. In addition, the second drive shaft 36 is supported on the support link 30 via a bearing, and is fixed to the first portion of the second drive link 32, and connects the second portion of the support link 30 and the first portion of the second drive link 32. The first connecting shaft 37 is supported on one or both of the second portion of the second drive link 32 and the first portion of the first driven link 33 via a bearing, and rotatably connects the second portion of the second drive link 32 and the first portion of the first driven link 33. The second connecting shaft 38 is supported on one or both of the second portion of the first drive link 31 and the first portion of the second driven link 34 via a bearing, and rotatably connects the second portion of the first drive link 31 and the first portion of the second driven link 34. The third connecting shaft 39 is supported on one or both of the second part of the first driven link 33 and the second part of the second driven link 34 via a bearing, and rotatably connects the second part of the first driven link 33 and the second part of the second driven link 34. In addition, the axes of the first drive shaft 35, the second drive shaft 36, the first connecting shaft 37, the second connecting shaft 38, and the third connecting shaft 39 extend in a direction orthogonal to the rotation axis and extend parallel to each other. That is, the supporting link 30 constitutes a stationary joint in the connecting rod structure 11. The first driving link 31 and the second driving link 32 respectively constitute the first and second driving joints in the connecting rod structure 11. The first driven link 33 and the second driven link 34 respectively constitute the first and second driven joints in the connecting rod structure 11. Therefore, the connecting rod structure 11 is a five-link structure of a closed loop structure in which five links are connected by five rotating sub-rings, and is a two-degree-of-freedom connecting rod mechanism.

[0030] In addition, the first drive shaft 35, the second drive shaft 36, the first connecting shaft 37, the second connecting shaft 38 and the third connecting shaft 39 are parallel to each other. In addition, the distance between the first drive shaft 35 and the second connecting shaft 38 is equal to the distance between the first connecting shaft 37 and the third connecting shaft 39, and the distance between the second drive shaft 36 and the first connecting shaft 37 is equal to the distance between the second connecting shaft 38 and the third connecting shaft 39. Therefore, when viewed from the extension direction of the first drive shaft 35, the first drive link 31, the second drive link 32, the first driven link 33 and the second driven link 34 of the connecting rod structure 11 extend in a manner that forms a substantially parallelogram. In addition, the supporting link 30 connects the first drive link 31 and the second drive link 32, and as described above, the connecting rod structure 11 becomes a five-link structure of a closed loop structure.

[0031] Moreover, the intervals between the axes of the first drive shaft 35 and the second drive shaft 36 and the axis of the first connecting shaft 37, and the intervals between the axes of the second connecting shaft 38 and the axis of the third connecting shaft 39 are the same. In addition, the intervals between the axes of the first drive shaft 35 and the second drive shaft 36 and the axis of the second connecting shaft 38, and the intervals between the axes of the first connecting shaft 37 and the axis of the third connecting shaft 39 are the same. That is, the connecting rod structure 11 has a parallel connecting rod structure. Moreover, the first driving link 31 and the first driven link 33 swing symmetrically, and then the second driving link 32 and the second driven link 34 also swing symmetrically. In addition, the angle formed by the first driving link 31 and the second driving link 32, that is, the opening angle θ, is the same as the angle formed by the first driven link 33 and the second driven link 34. Therefore, the second driven link 34 can maintain a posture relative to the second driving link 32. In addition, the opening angle θ, which is the angle formed by the first drive link 31 and the second drive link 32, is the angle formed by the plane passing through the axis of the first drive shaft 35 and the second drive shaft 36 and the axis of the second connecting shaft 38 and the plane passing through the axis of the first drive shaft 35 and the second drive shaft 36 and the axis of the first connecting shaft 37. In addition, the angle formed by the first driven link 33 and the second driven link 34 is the angle formed by the plane passing through the axis of the third connecting shaft 39 and the axis of the second connecting shaft 38 and the plane passing through the axis of the third connecting shaft 39 and the axis of the first connecting shaft 37. In this way, the coaxial first drive shaft 35 and the second drive shaft 36 constitute a reference axis with the opening angle θ. And, the first drive shaft 35 rotatably supports the first drive link 31 around the reference axis, and the second drive shaft 36 rotatably supports the second drive link 32 around the reference axis.

[0032] Then, the first drive unit 14 of the lower arm rotates the first drive shaft 35 using its own driving force, and drives the first drive link 31 to swing. In addition, the second drive unit 15 of the lower arm rotates the second drive shaft 36 using its own driving force, and drives the second drive link 32 to swing. The first drive unit 14 of the lower arm and the second drive unit 15 of the lower arm are provided with a servo motor and a reducer mounted on the supporting link 30, and the output shaft of the servo motor is fixedly connected to the first drive shaft 35 and the second drive shaft 36 via the reducer, respectively. Therefore, the first drive link 31 and the second drive link 32 are configured to swing independently of each other. In the extension direction of the axis of the first drive shaft 35 and the second drive shaft 36, the first drive unit 14 of the lower arm is arranged on one side of the first drive link 31, and the second drive unit 15 of the lower arm is arranged on the other side of the first drive link 31. In addition, the first drive unit 14 of the lower arm and the second drive unit 15 of the lower arm respectively have encoders 14a and 15a for detecting the angular position of the output shaft of the servo motor. As Figure 5 As shown, the angular position information of the output shaft of the servo motor detected by the encoders 14 a and 15 a is input to a calculation unit 21 and a servo amplifier 23 of the robot controller 2 , which will be described later.

[0033] Therefore, if Figure 3 As shown, when the first driving portion 14 of the lower arm rotates the first driving shaft 35 using its own driving force, the end of the first driving link 31 on the side of the second connecting shaft 38 swings in the front-rear direction. Furthermore, driven by the action of the first driving link 31, the end of the first driven link 33 on the side of the third connecting shaft 39 swings in the front-rear direction, and the second driven link 34 mainly moves forward and backward in the front-rear direction. Furthermore, the upper arm structure 12 mainly moves forward and backward in the front-rear direction, and the hand 8 mainly moves in the front-rear direction. In addition, as Figure 4 As shown, when the lower arm second driving part 15 rotates the second driving shaft 36 by its own driving force, the end of the second driving link 32 on the first connecting shaft 37 side swings in the up-down direction. And, driven by the second driving link 32, the second driven link 34 swings around the second connecting shaft 38. And, the upper arm structure 12 rotates around the second connecting shaft 38, and the hand 8 moves mainly in the up-down direction.

[0034]

Robot controller configuration example

[0035] Figure 5 1 is a block diagram schematically showing a configuration example of a control system of the robot system 100 .

[0036] like Figure 1 As shown in FIG. 1 , the robot controller 2, also called a robot control device, is disposed around the robot body 1 and performs position control, speed control, or current control of the control target axis of the robot body 1. Figure 5 As shown, the robot controller 2 includes, for example, a computing unit 21 having a computing unit such as a CPU, a storage unit 22 having a memory such as a ROM and a RAM, and a plurality of servo amplifiers 23 provided corresponding to the servo motors of the first lower arm driving unit 14, the second lower arm driving unit 15, and the joint driving unit 13. In addition, the robot controller 2 estimates the deflection amount δ of the link structure 11, that is, the displacement amount of the position and posture of the second driven link 34 relative to the supporting link 30 caused by the deflection of the link structure 11. The robot controller 2 may be composed of a single controller for centralized control, or may be composed of a plurality of controllers for coordinated decentralized control.

[0037] The operation unit 21 includes an opening angle calculation unit 25, a load calculation unit 26, a stiffness matrix determination unit 27, a deflection amount calculation unit 28, and a command generation unit 29. The opening angle calculation unit 25, the load calculation unit 26, the stiffness matrix determination unit 27, and the deflection amount calculation unit 28 constitute a deflection amount estimation device. Functional units 25 to 29 are functional blocks implemented by the operation unit 21 executing a prescribed control program stored in the storage unit 22. At least one prescribed control program is stored in the storage unit 22, and the operation unit 21 reads and executes the control program, so that the movement of the robot body 1 is controlled. In addition, the storage unit 22 stores a stiffness value determination function described later.

[0038] The deflection amount estimating device is a device that estimates the dynamic deflection amount of the link structure 11 caused by the dynamic load generated by the acceleration and deceleration of the robot arm 7 when the robot arm 7 is moved. Specifically, the deflection amount estimating device is a device that estimates the displacement amount of the proximal end of the link structure 11, that is, the position and posture relative to the distal end of the support link 30, that is, the second driven link 34.

[0039] The servo amplifier 23 controls the corresponding servo motor. Specifically, the servo amplifier 23 performs follow-up control of the servo motor in position control so that the deviation between the current position and the angular position of the output shaft of the servo motor determined based on the position command value generated by the command generating unit 29 becomes zero.

[0040] [Action example]

[0041] Next, an operation example of the deflection amount estimation operation of the robot system 10 will be described.

[0042] Figure 6 : is a flowchart showing an operation example of the deflection amount estimation operation of the robot system 10 .

[0043] First, in step S1, the opening angle calculation unit 25 calculates the angle, i.e., the opening angle θ, formed by the first drive link 31, one link of the link structure 11 rotating about the reference axis formed by the first drive shaft 35 and the second drive shaft 36, which are axes of one rotation pair of the link structure 11, and the second drive link 32, another link of the link structure 11 rotating about the reference axis. Specifically, the opening angle calculation unit 25 calculates the opening angle θ, the angle formed by the first drive link 31 and the second drive link 32, based on the angular position information of the output shaft of the servo motor driving the first drive link 31 and the angular position information of the output shaft of the servo motor driving the second drive link 32. The angular position information of the output shaft of the servo motor driving the first drive link 31 is detected by the encoder 14a of the first drive unit 14 of the lower arm, and the angular position information of the output shaft of the servo motor driving the second drive link 32 is detected by the encoder 15a of the second drive unit 15 of the lower arm. In addition, the angle formed by two connecting rods connected to the first connecting shaft 37, the second connecting shaft 38, or the third connecting shaft 39 may be used as the opening angle.

[0044] Next, in step S3, the load calculation unit 26 calculates the load on the link structure 11. In the present embodiment, the load on the link structure 11 refers to the dynamic load on the link structure 11 as the link accelerates and decelerates when the robot arm 7 moves. The load calculation unit 26 processes the load amount in a signed manner, for example, when the robot arm 7 starts to swing, a + load is generated by the acceleration link, and when the swing ends, a - load is generated by the deceleration link.

[0045] Next, in step S5, the stiffness matrix determination unit 27 determines the values ​​of each component of the stiffness matrix C (rigidity matrix) corresponding to the opening angle θ, that is, the stiffness value. The stiffness matrix C is a 6×6 symmetric matrix that associates the load w received by the link structure 11 with the deflection δ of the link structure 11, and has 36 components c11 to c66 shown in the following equation (1). The load w is a force in six directions of force and momentum, and is a wrench.

[0046] [Mathematical formula 1]

[0047]

[0048] The stiffness matrix determination unit 27 uses the stiffness matrix of the respective c 11 ~c 66 The stiffness value is determined by the stiffness value determination function specified by the 36 components of c. 11 ~c 66 Excluding the symmetric components, there are 21 components in total.

[0049] The stiffness value determination function is a function that represents the correlation between the stiffness value and the opening angle θ of the connecting rod structure 11, and is calculated by analysis using the finite element method (FEM). That is, first, stiffness values ​​corresponding to multiple opening angles θ that are different from each other are obtained in advance by analysis. Specifically, for the first drive link 31, the angle in the vertical extension state is 0°. The state of tilting forward is positive, and the state of tilting backward is negative. In addition, for the second drive link 32, the angle in the horizontal extension state is 0°, the state of tilting upward is negative, and the state of tilting backward is positive. And, the sum of the angle of the first drive link 31 and the angle of the second drive link 32 is taken as the opening angle θ. And, for example, for the states where the opening angle θ is -66°, -44°, -22°, 0°, 22°, 44°, and 66°, the stiffness values ​​are obtained respectively. Then, the stiffness values ​​corresponding to the multiple opening angles θ obtained by analysis are linearly interpolated. And, the linearly complemented function is used as the stiffness value determination function. Figure 7 Indicates c 36 An example of a function for determining the stiffness value of a component. In addition, Figure 8 Represents C 13 An example of a function for determining the stiffness value of a component. In addition, the sampling interval for obtaining the stiffness value by the finite element method is set to represent the tendency of the stiffness value change by linear interpolation, such as Figure 7 and Figure 8 As shown, for example, by acquiring stiffness values ​​at intervals of 22°, it is possible to acquire a trend of changes in stiffness values.

[0050] Next, in step S7, the deflection amount calculation unit 28 calculates the deflection amount δ of the link structure 11 based on the load received by the link structure 11 calculated by the load calculation unit 26 and the stiffness matrix C determined based on the stiffness value determined by the stiffness matrix determination unit 27. That is, the deflection amount calculation unit 28 calculates the deflection amount δ using the function involved in the following formula (2).

[0051] [Mathematical formula 2]

[0052] δ=Cw…(2)where,

[0053] w=[f x f y f z m x m y m z ] T

[0054] f x 、f y 、f z are the x, y, and z components of force F, respectively.

[0055] mx 、m y 、m z are the components of momentum M around the x-axis, y-axis, and z-axis respectively

[0056] However, generally, in a serial link, the relationship between the load w and the deflection δ is linear. However, in a link structure, such as Figure 7 and Figure 8 As shown in FIG. 1 , the relationship between the load w and the deflection δ is nonlinear, and the stiffness matrix C has stiffness values ​​showing different changing tendencies in the components according to the opening angle θ, so it is difficult to estimate the deflection δ. However, the deflection estimating device of the robot system 10 uses the stiffness matrix C having stiffness values ​​determined according to the opening angle θ in the components. 11 ~c 66 The stiffness matrix C of the connecting rod structure can be used to quickly estimate the deflection δ of the connecting rod structure. Therefore, for example, compared with the case of solving the equations representing the relationship between the load w of each connecting rod and the deflection δ simultaneously, the amount of calculation can be reduced, and the deflection δ can be quickly calculated. Therefore, the movement speed of the robot body 1 can be improved. In addition, as shown in equation (2), in the estimation of the dynamic deflection δ, the influence of the gravity component is slight, so the influence of the gravity component is ignored.

[0057] Next, in step S7, the command generation unit 29 generates a command value according to the motion program. When generating the command value, the command generation unit 29 calculates a compensation amount corresponding to the dynamic deflection amount δ of the link structure 11 calculated by the deflection amount calculation unit 28. The compensation amount is proportional to the acceleration of the link structure 11, and the compensation amount at the beginning of the swing and the compensation amount at the end of the motion have opposite signs. Therefore, the vibration of the robot arm 7 accompanying the acceleration and deceleration of the robot arm 7 can be suppressed.

[0058] As described above, the deflection amount estimation device uses the component having the stiffness value c determined according to the opening angle θ. 11 ~c 66 The bending amount δ of the two-degree-of-freedom link structure can be estimated quickly by using the stiffness matrix C. Therefore, the amount of calculation can be reduced, and the bending amount δ can be calculated quickly. Therefore, the movement speed of the robot body 1 can be increased.

[0059] <Modification>

[0060] In the above embodiment, the deflection amount estimating device estimates the dynamic deflection amount δ. Instead of estimating the dynamic deflection amount δ, the deflection amount estimating device may calculate the static load by the load calculating unit 26, and the deflection amount calculating unit 28 may estimate the static deflection amount based on the relationship between the static load and the static deflection amount.

[0061] Furthermore, in the above-described embodiment, the first joint axis JT1 connects the lower arm structure and the base 6 so as to be rotatable about a rotation axis extending in the vertical direction. Fig. 9 As shown, the first joint JT1 can also rotatably connect the lower arm structure and the base 6 around a bending axis extending in the horizontal direction. Even if the posture of the lower arm structure relative to the base 6 and the ground contact surface of the robot body 1 changes due to the bending action of the first joint JT1, the robot system 100 can estimate the deflection amount δ of the link structure 11.

[0062] Based on the above description, many improvements or other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be interpreted as illustrative only and is provided to teach those skilled in the art to perform the best aspects of the present invention. The details of the structure and / or function described above may be substantially changed without departing from the spirit of the present invention.

[0063] (Examples of Embodiments)

[0064] Embodiment 1: A deflection amount estimation device estimates a deflection amount δ of a link structure 11 of a robot arm 7 formed by connecting a plurality of links including a link structure 11 having two degrees of freedom with a plurality of revolute pairs through joints, wherein the device comprises:

[0065] an opening angle calculation unit 25 for calculating an opening angle θ which is an angle formed by one link 31 of the link structure 11 rotating about a reference axis which is an axis of a revolute pair of the link structure 11 and another link 32 of the link structure 11 rotating about the reference axis;

[0066] a load calculation unit 26 for calculating the load on the connecting rod structure 11;

[0067] The stiffness matrix determination unit 27 determines the stiffness value corresponding to the opening angle θ of the link structure 11 calculated by the opening angle calculation unit 25 by using a stiffness value determination function representing each component c of the stiffness matrix C that relates the load received by the link structure 11 to the deflection amount δ of the link structure 11. 11 ~c 66 The value of , that is, the correlation between the rigidity value and the opening angle θ of the connecting rod structure 11; and

[0068] The deflection amount calculation unit 28 calculates the load on the link structure 11 calculated by the load calculation unit 26 and the stiffness value c determined by the stiffness matrix determination unit 27 in the component. 11 ~c 66 The stiffness matrix C is used to calculate the deflection δ of the connecting rod structure 11.

[0069] According to the first embodiment, the deflection amount δ of the link structure 11 can be estimated. In addition, since the link structure 11 can have multiple degrees of freedom, the structure of the distal end side of the link structure 11 of the robot arm 7 can be simplified. 11 ~c 66 The stiffness matrix C can be used to quickly estimate the deflection amount δ of the link structure 11. Therefore, the amount of calculation in the process of calculating the deflection amount δ can be reduced, and the deflection amount δ can be quickly calculated.

[0070] Embodiment 2: The deflection amount estimating device according to Embodiment 1, wherein the link structure 11 is a five-link structure of a closed loop structure.

[0071] According to the second embodiment, the deflection amount δ of the five-link structure of the closed loop can be quickly calculated.

[0072] Embodiment 3: A deflection amount estimation device according to embodiment 1 or 2, wherein:

[0073] The link structure 11 includes a first driving link 31 as one link, a second driving link 32 as another link, a first driven link 33, a second driven link 34, a first driving shaft 35 rotatably supporting the first driving link 31 around a reference axis, a second driving shaft 36 rotatably supporting the second driving link 32 around a reference axis, a first connecting shaft 37 rotatably connecting the second driving link 32 and the first driven link 33, a second connecting shaft 38 rotatably connecting the first driving link 31 and the second driven link 34, and a third connecting shaft 39 rotatably connecting the first driven link 33 and the second driven link 34.

[0074] The first drive unit 14 for swing-driving the first drive link 31 around the first drive shaft 35 and the second drive unit 15 for swing-driving the second drive shaft 32 around the second drive shaft 36 are further provided.

[0075] According to the third embodiment, the link structure 11 can be swung in multiple directions, and the number of joints connected to the distal end of the robot arm 7 can be reduced.

[0076] Embodiment 4: The deflection amount estimating device according to Embodiment 3, wherein the link structure 11 further includes a supporting link 30,

[0077] The first drive shaft 35 connects the support link 30 and the first drive link 31 rotatably around the reference axis.

[0078] The second drive shaft 36 connects the support link 30 and the second drive link 32 so as to be rotatable around a reference axis.

[0079] Embodiment 5: The deflection amount estimating device according to Embodiment 3, wherein the first drive shaft 35, the second drive shaft 36, the first connecting shaft 37, the second connecting shaft 38, and the third connecting shaft 39 are parallel to each other.

[0080] The distance between the first drive shaft 35 and the second connecting shaft 38 is equal to the distance between the first connecting shaft 37 and the third connecting shaft 39.

[0081] The distance between the second drive shaft 36 and the first connecting shaft 37 is equal to the distance between the second connecting shaft 38 and the third connecting shaft 39 .

[0082] According to the fifth embodiment, the deflection amount δ of the link structure portion 11 can be estimated more accurately.

[0083] Embodiment 6: A deflection estimation device according to any one of embodiments 1 to 3, wherein the stiffness value determination function is a function that obtains stiffness values ​​corresponding to a plurality of different opening angles θ in advance through analysis, and performs linear interpolation on the stiffness values ​​corresponding to the plurality of opening angles θ obtained through analysis.

[0084] According to the sixth embodiment, the amount of calculation in the process of calculating the deflection amount δ can be reduced, and the deflection amount δ can be calculated quickly.

[0085] Embodiment 7: A deflection estimation device, comprising: a memory storing at least one program; a processor, which calculates the estimated deflection of a link structure 11 of a robot arm 7 by executing at least one program, wherein the robot arm 7 is composed of a plurality of links including a link structure 11 having two degrees of freedom with a plurality of revolute pairs connected by joints, wherein:

[0086] The processor performs:

[0087] an opening angle calculation process for calculating an opening angle formed by one link of the link structure 11 rotating about a reference axis as an axis of a revolute pair of the link structure 11 and another link of the link structure 11 rotating about the reference axis;

[0088] A load calculation process, which calculates the load on the connecting rod structure 11;

[0089] A stiffness matrix determination process is performed to determine a stiffness value corresponding to the opening angle θ of the link structure 11 calculated by the opening angle calculation process by using a stiffness value determination function representing each component c of a stiffness matrix that relates a load received by the link structure 11 to a deflection amount δ of the link structure 11. 11 ~c 66 The value of , that is, the correlation between the rigidity value and the opening angle θ of the connecting rod structure 11; and

[0090] The deflection amount calculation process is to calculate the load on the link structure 11 calculated in the load calculation process and the stiffness value c determined in the stiffness matrix determination process in the component. 11 ~c 66 The stiffness matrix C is used to calculate the deflection δ of the connecting rod structure 11.

[0091] According to the seventh embodiment, the deflection amount δ of the link structure 11 can be estimated. In addition, since the link structure 11 can have multiple degrees of freedom, the structure of the robot arm can be simplified. 11 ~c 66 The stiffness matrix C can be used to quickly estimate the deflection amount δ of the link structure 11. Therefore, the amount of calculation in the process of calculating the deflection amount δ can be reduced, and the deflection amount δ can be quickly calculated.

[0092] Embodiment 8: A robot control device, comprising the deflection amount estimating device described in any one of Embodiments 1 to 7.

[0093] According to the eighth embodiment, by using the component having a stiffness value c determined according to the opening angle θ 11 ~c 66 The stiffness matrix C can be used to quickly estimate the deflection amount δ of the link structure 11. Therefore, the amount of calculation can be reduced, and the deflection amount δ can be quickly calculated. Therefore, the movement speed of the robot body 1 can be increased.

[0094] Embodiment 9: A method for estimating a deflection amount, which detects a deflection amount δ of a link structure 11 of a robot arm 7, wherein the robot arm is formed by connecting a plurality of links including a link structure 11 having two degrees of freedom with a plurality of revolute pairs through joints, wherein:

[0095] Calculating an opening angle, which is an angle formed by one link 31 of the link structure 11 rotating about a reference axis as an axis of a revolute pair of the link structure 11 and another link 32 of the link structure 11 rotating about the reference axis;

[0096] Calculate the load on the connecting rod structure 11;

[0097] The stiffness value corresponding to the calculated opening angle θ of the link structure 11 is determined by using a stiffness value determination function representing each component c of a stiffness matrix that relates the load applied to the link structure 11 to the deflection amount δ of the link structure 11. 11 ~c 66 The value of , that is, the correlation between the rigidity value and the opening angle θ of the connecting rod structure 11; and

[0098] According to the calculated load on the connecting rod structure 11 and the stiffness value c in the component 11 ~c 66 The stiffness matrix C is used to calculate the deflection δ of the connecting rod structure 11.

[0099] According to the ninth embodiment, the deflection amount δ of the link structure 11 can be estimated. In addition, since the link structure 11 can have multiple degrees of freedom, the structure of the robot arm can be simplified. Furthermore, by using the stiffness matrix C having stiffness values ​​c11 to c6 determined based on the opening angle θ in the components, the deflection amount δ of the link structure 11 can be estimated quickly. Therefore, the amount of calculation in the process of calculating the deflection amount δ can be reduced, and the deflection amount δ can be calculated quickly.

[0100] Description of Figure Numbers

[0101] 1 Robot body

[0102] 2 Robot Controller

[0103] 6 Base

[0104] 7 Robotic Arm

[0105] 8 hands

[0106] 11 Connecting rod structure

[0107] 12 Upper arm structure

[0108] 13 Joint drive unit

[0109] 13a Encoder

[0110] 14 Lower arm first drive unit

[0111] 14a Encoder

[0112] 15 Lower arm second drive unit

[0113] 15a Encoder

[0114] 21. Operation unit

[0115] 22 Storage

[0116] 23 Servo amplifier

[0117] 25 Opening angle calculation section

[0118] 26 Load Calculation Department

[0119] 27 Stiffness Matrix Determination

[0120] 28 Deflection calculation section

[0121] 29 Instruction generation unit

[0122] 30 Support connecting rod

[0123] 31 First drive connecting rod

[0124] 32 Second driving connecting rod

[0125] 33 First driven connecting rod

[0126] 34 Second driven connecting rod

[0127] 35 First drive shaft

[0128] 36 Second drive shaft

[0129] 37 First connecting shaft

[0130] 38 Second connecting shaft

[0131] 39 Third connecting shaft

[0132] 100 Robotic Systems

Claims

1. A deflection estimation device for estimating the deflection of a link structure of a robot arm formed by connecting a plurality of links including a link structure with two degrees of freedom having a plurality of revolute pairs through joints, characterized in that: have: an opening angle calculation unit that calculates an opening angle, the opening angle being an angle formed by one link of the link structure unit rotating about a reference axis that is an axis of a revolute pair of the link structure unit and another link of the link structure unit rotating about the reference axis; a load calculation unit, which calculates the load on the connecting rod structure; a stiffness matrix determination unit that determines the stiffness value corresponding to the opening angle of the connecting rod structure portion calculated by the opening angle calculation unit by using a stiffness value determination function that indicates a correlation between a stiffness value and the opening angle of the connecting rod structure portion, the stiffness value being a value of each component of a stiffness matrix that associates a load received by the connecting rod structure portion with a deflection amount of the connecting rod structure portion; as well as A deflection amount calculation unit calculates a deflection amount of the link structure portion based on the load applied to the link structure portion calculated by the load calculation unit and the stiffness matrix having the stiffness values ​​determined by the stiffness matrix determination unit in its components.

2. The deflection amount estimating device according to claim 1, characterized in that: The connecting rod structure is a five-link structure with a closed loop structure.

3. The deflection amount estimating device according to claim 1, characterized in that: The link structure portion includes: a first driving link as the one link, a second driving link as the other link, a first driven link, a second driven link, a first driving shaft rotatably supporting the first driving link around the reference axis, a second driving shaft rotatably supporting the second driving link around the reference axis, a first connecting shaft rotatably connecting the second driving link and the first driven link, a second connecting shaft rotatably connecting the first driving link and the second driven link, and a third connecting shaft rotatably connecting the first driven link and the second driven link. The invention further includes a first driving unit for swing-driving the first driving link about the first driving shaft and a second driving unit for swing-driving the second driving link about the second driving shaft.

4. The deflection amount estimating device according to claim 3, characterized in that: The connecting rod structure also has a supporting connecting rod. The first drive shaft connects the support link and the first drive link rotatably around the reference axis. The second drive shaft connects the support link and the second drive link so as to be rotatable around the reference axis.

5. The deflection amount estimating device according to claim 3, characterized in that: The first drive shaft, the second drive shaft, the first connecting shaft, the second connecting shaft, and the third connecting shaft are parallel to each other. The distance between the first drive shaft and the second connecting shaft is equal to the distance between the first connecting shaft and the third connecting shaft, The distance between the second drive shaft and the first connecting shaft is equal to the distance between the second connecting shaft and the third connecting shaft.

6. The deflection amount estimating device according to claim 1, characterized in that: The stiffness value determination function is a function that obtains the stiffness values ​​corresponding to the plurality of opening angles that are different from each other in advance by analysis, and performs linear interpolation on the stiffness values ​​corresponding to the plurality of opening angles obtained by analysis.

7. A deflection estimation device comprising: a memory storing at least one program; and A processor, which calculates an estimated deflection amount of a link structure of a robot arm including a link structure having two degrees of freedom and a plurality of revolute pairs, wherein the link structure is connected by joints, by executing the at least one program, characterized in that: The processor performs: an opening angle calculation process for calculating an opening angle, the opening angle being an angle formed by one link of the link structure part rotating about a reference axis as an axis of a revolute pair of the link structure part and another link of the link structure part rotating about the reference axis; A load calculation process, which calculates the load on the connecting rod structure; a stiffness matrix determination process of determining the stiffness value corresponding to the opening angle of the link structure portion calculated in the opening angle calculation process by using a stiffness value determination function, the stiffness value determination function indicating a correlation between a stiffness value and the opening angle of the link structure portion, the stiffness value being a value of each component of a stiffness matrix in which a load applied to the link structure portion is associated with a deflection amount of the link structure portion; as well as A deflection amount calculation process calculates the deflection amount of the link structure portion based on the load applied to the link structure portion calculated in the load calculation process and the stiffness matrix having the stiffness values ​​determined in the stiffness matrix determination process in its components.

8. A robot control device, characterized in that: A device comprising the deflection amount estimating device according to any one of claims 1 to 7.

9. A method for estimating deflection, which detects the deflection of a link structure of a robot arm including a link structure having two degrees of freedom and a plurality of revolute pairs, wherein the link structure is connected by joints, wherein: calculating an opening angle, the opening angle being an angle formed by one link of the link structure part rotating about a reference axis as an axis of a revolute pair of the link structure part and another link of the link structure part rotating about the reference axis; Calculating the load on the connecting rod structure; determining the stiffness value corresponding to the calculated opening angle of the connecting rod structure portion by using a stiffness value determination function, the stiffness value determination function representing a correlation between a stiffness value and the opening angle of the connecting rod structure portion, the stiffness value being a value of each component of a stiffness matrix in which a load on the connecting rod structure portion is associated with a deflection amount of the connecting rod structure portion; as well as The deflection amount of the link structure portion is calculated based on the calculated load to which the link structure portion is subjected and the stiffness matrix having the determined stiffness values ​​in its components.

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