Deflection amount estimation device, robot control device, and deflection amount estimation method
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KAWASAKI JUKOGYO KK
- Filing Date
- 2022-06-09
- Publication Date
- 2026-08-05
Smart Images
Figure 0007900954000003 
Figure 0007900954000004 
Figure 0007900954000005
Abstract
Description
[Technical Field]
[0001] The present invention relates to a deflection amount estimation device, a robot control device, and a deflection amount estimation method. [Background technology]
[0002] Conventionally, for example in Patent Document 1, a deflection estimation device for calculating the deflection of a link structure in a robot arm including a link structure has been proposed. The deflection estimation device of Patent Document 1 calculates the estimated deflection based on the oscillation angle of the four-bar link structure. This makes it possible to quickly estimate the deflection of the four-bar link structure, and consequently, to achieve higher speeds for reducing cycle time and lighter links in the arm. [Prior art documents] [Patent Documents]
[0003] [Patent Document 1] Japanese Patent Publication No. 2019-195892 [Overview of the project] [Problems that the invention aims to solve]
[0004] Incidentally, the deflection estimation device described in Patent Document 1 estimates the amount of deflection of a link structure whose movement can be defined based on the orientation of one link. Therefore, the deflection estimation device described in Patent Document 1 cannot be applied to a two-degree-of-freedom link structure where the movement of the link structure cannot be defined by the orientation of one link, which has limitations in terms of increasing speed and reducing the weight of the arm links. [Means for solving the problem]
[0005] To solve the above problems, a deflection amount estimation device according to one aspect of the present invention is a deflection amount estimation device for estimating the deflection amount of a link structure of a robot arm, which is made up of multiple links connected by joints, including a link structure with two degrees of freedom having multiple rotational pairs, and includes an opening angle calculation unit that calculates the opening angle, which is the angle formed between one link of the link structure that rotates around a reference axis which is the axis of one rotational pair of the link structure, and another link of the link structure that rotates around the reference axis, and a load calculation unit that calculates the load on the link structure The device comprises: an outlet; a stiffness matrix determination unit that determines the stiffness value corresponding to the opening angle of the link structure calculated by the opening angle calculation unit, using a stiffness value determination function that represents the correlation between the stiffness value, which is the value of each component of a stiffness matrix relating the load received by the link structure to the amount of deflection of the link structure, and the opening angle of the link structure; and a deflection amount calculation unit that calculates the amount of deflection of the link structure based on the load received by the link structure calculated by the load calculation unit and the stiffness matrix having the stiffness value determined by the stiffness matrix determination unit as components.
[0006] According to the above configuration, the amount of deflection of a link structure with two degrees of freedom can be estimated. Furthermore, since the link structure can have multiple degrees of freedom, the structure of the distal end of the link structure of the robot arm can be simplified. In addition, the amount of deflection of the link structure can be quickly estimated using a stiffness matrix whose components include stiffness values determined based on the opening angle. Therefore, the amount of computation required in the process of calculating the amount of deflection can be reduced, and the amount of deflection can be calculated quickly. [Effects of the Invention]
[0007] This invention has the effect of being able to estimate the amount of deflection of a link structure with two degrees of freedom. [Brief explanation of the drawing]
[0008] [Figure 1] This figure shows an example configuration of a robot system including a deflection amount estimation device according to an embodiment. [Figure 2]It is a diagram schematically showing a configuration example of a robot main body of the robot system in FIG. 1. [Figure 3] It is a diagram schematically showing an operation example of the robot main body of the robot system in FIG. 1, and is a diagram showing the rotation operation of the first drive link. [Figure 4] It is a diagram schematically showing an operation example of the robot main body of the robot system in FIG. 1, and is a diagram showing the rotation operation of the first drive link. [Figure 5] It is a block diagram schematically showing a configuration example of a control system of the robot system in FIG. 1. [Figure 6] It is a flowchart showing an operation example related to the deflection amount estimation operation of the robot system in FIG. 1. [Figure 7] It is a diagram showing an example of a rigidity value determination function used in the deflection amount estimation operation of the robot system in FIG. 1. [Figure 8] It is a diagram showing an example of a rigidity value determination function used in the deflection amount estimation operation of the robot system in FIG. 1. [Figure 9] It is a diagram showing a modification example of the robot main body shown in FIG. 2.
Mode for Carrying Out the Invention
[0009] Hereinafter, embodiments will be described with reference to the drawings. Note that the present invention is not limited by the present embodiments. Also, hereinafter, throughout all the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions thereof are omitted. The functions of the elements disclosed in this specification can be executed using a circuit or processing circuit including a general-purpose processor, a dedicated processor, an integrated circuit, an ASIC (Application Specific Integrated Circuits), a conventional circuit, and / or a combination thereof that is configured or programmed to execute the disclosed functions. Since a processor includes transistors and other circuits, it is regarded as a processing circuit or a circuit. In the present disclosure, a circuit, unit, or means is hardware that executes the recited functions or hardware programmed to execute the recited functions. The hardware may be the hardware disclosed in this specification or other known hardware that is programmed or configured to execute the recited functions. When the hardware is a processor that is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used for the configuration of the hardware and / or the processor.
[0010] FIG. 1 is a diagram showing a configuration example of a robot system 100 including a deflection amount estimation device according to an embodiment. As shown in FIG. 1, the robot system 100 includes a robot body 1 and a robot controller 2.
[0011] [Configuration Example of Robot Body] FIG. 2 is a diagram schematically showing a configuration example of the robot body 1. As shown in FIG. 2, the robot body 1 is an articulated industrial robot. Also, the robot body 1 is a robot that uses a 5-link structure with a closed-loop structure for the lower arm structure that supports the upper arm structure 12 and the hand 8 described later, has high mechanical rigidity, and can realize stable operation under high load conditions.
[0012] The robot body 1 includes a base 6, a robot arm 7, and a hand 8. The base 6 is fixed and mounted on, for example, the floor, and supports the robot arm 7 and the hand 8.
[0013] The robot arm 7 has a structure in which multiple 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 called the link structure 11 and is rotatably connected to the base 6, for example, around a pivot axis extending in the vertical direction. The structure connecting the base 6 and the link structure 11 is the first joint axis JT1. The link structure 11 also has a second joint axis JT2 and a third joint axis JT3. The upper arm structure 12 is provided continuously with the link structure 11. 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 has a total of six joint axes. Of the six joint axes, four joint axes, excluding the link structure 11, are driven by joint drive units 13 provided corresponding to each joint, causing the distal end link to rotate around the rotation axis relative to the proximal end link. 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 link structure and is configured similarly to the upper arm structure of a well-known vertical multi-joint 6-axis robot, so a detailed explanation is omitted. In this specification, the term distal end refers to the hand 8 side in the direction in which the robot arm 7 extends, and the term proximal end refers to the base 6 side.
[0014] The link structure 11 includes a support link 30, a first drive link 31, a second drive link 32, a first driven link 33, a second driven link 34, a first drive shaft 35, a second drive shaft 36, a first connecting shaft 37, a second connecting shaft 38, and a third connecting shaft 39. The support link 30 is connected to the base 6 via a bearing and is rotatably connected to the base 6 around a pivot axis. In the basic posture of the robot body 1, the first drive link 31 and the first driven link 33 extend in the vertical direction, and the second drive link 32 and the second driven link 34 extend in the front-rear direction. The support link 30, the first drive link 31, the second drive link 32, the first driven link 33, and the second driven link 34 each have a first part and a second part. In the first drive link 31, the second drive link 32, the first driven link 33, and the second driven link 34, the first part refers to one end and the second part refers to the other end. The second driven link 34 is integrally molded with and continuous with the proximal end portion of the upper arm structure 12.
[0015] The first drive shaft 35 is supported by the support link 30 via a bearing and fixed to the first part of the first drive link 31, connecting the first part of the support link 30 and the first part of the first drive link 31. The second drive shaft 36 is provided coaxially with the first drive shaft 35. The second drive shaft 36 is supported by the support link 30 via a bearing and fixed to the first part of the second drive link 32, connecting the second part of the support link 30 and the first part of the second drive link 32. The first connecting shaft 37 is supported by bearings on one or both of the second part of the second drive link 32 and the first part of the first driven link 33, rotatably connecting the second part of the second drive link 32 and the first part of the first driven link 33. The second connecting shaft 38 is supported via bearings on either or both of the second portion of the first drive link 31 and the first portion of the second driven link 34, rotatably connecting 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 via bearings on either or both of the second portion of the first driven link 33 and the second portion of the second driven link 34, rotatably connecting the second portion of the first driven link 33 and the second portion of the second driven link 34. Furthermore, 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 perpendicular to the pivot axis and are parallel to each other. That is, the support link 30 forms a stationary link in the link structure 11. The first drive link 31 and the second drive link 32 constitute the first and second driving links in the link structure 11, respectively. The first driven link 33 and the second driven link 34 constitute the first and second driven links in the link structure 11, respectively. Therefore, the link structure 11 is a five-bar link with a closed-loop structure in which five links are connected in a ring shape by five rotational pairs, and is a link mechanism with two degrees of freedom.
[0016] Furthermore, 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. Also, 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, the first drive link 31, the second drive link 32, the first driven link 33, and the second driven link 34 of the link structure 11 extend in a substantially parallelogram shape when viewed from the direction of extension of the first drive shaft 35. The support link 30 connects the first drive link 31 and the second drive link 32, and as described above, the link structure 11 is a closed-loop five-bar link structure.
[0017] Furthermore, the distance between the axes of the first drive shaft 35 and the second drive shaft 36 and the axis of the first connecting shaft 37 is the same as the distance between the axis of the second connecting shaft 38 and the axis of the third connecting shaft 39. Also, the distance between the axes of the first drive shaft 35 and the second drive shaft 36 and the axis of the second connecting shaft 38 is the same as the distance between the axis of the first connecting shaft 37 and the axis of the third connecting shaft 39. In other words, the link structure 11 has a parallel link structure. The first drive link 31 and the first driven link 33 swing symmetrically, and the second drive link 32 and the second driven link 34 also swing symmetrically. In addition, the opening angle θ, which is the angle between the first drive link 31 and the second drive link 32, is configured to be the same as the angle between the first driven link 33 and the second driven link 34. Therefore, the second driven link 34 can maintain its orientation relative to the second drive link 32. The opening angle θ, which is the angle between the first drive link 31 and the second drive link 32, is the angle between the plane passing through 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 plane passing through the axes of the first drive shaft 35 and the second drive shaft 36 and the axis of the first connecting shaft 37. The angle between the first driven link 33 and the second driven link 34 is the angle between 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 form the reference axis related to the opening angle θ. The first drive shaft 35 supports the first drive link 31 so that it can rotate around the reference axis, and the second drive shaft 36 supports the second drive link 32 so that it can rotate around the reference axis.
[0018] The lower arm first drive unit 14 rotates the first drive shaft 35 with its own driving force, thereby oscillating the first drive link 31. Similarly, the lower arm second drive unit 15 rotates the second drive shaft 36 with its own driving force, thereby oscillating the second drive link 32. The lower arm first drive unit 14 and the lower arm second drive unit 15 are equipped with a servo motor and a reduction gear attached to the support link 30, and the output shafts of the servo motors are fixedly connected to the first drive shaft 35 and the second drive shaft 36, respectively, via the reduction gear. Therefore, the first drive link 31 and the second drive link 32 are configured to oscillate independently of each other. In the direction of extension of the axes of the first drive shaft 35 and the second drive shaft 36, the lower arm first drive unit 14 is located on one side of the first drive link 31, and the lower arm second drive unit 15 is located on the other side of the first drive link 31. Furthermore, the lower arm first drive unit 14 and the lower arm second drive unit 15 each have encoders 14a and 15a, respectively, for detecting the angular position of the output shaft of the servo motor. As shown in Figure 5, the angular position information of the output shaft of the servo motor detected by the encoders 14a and 15a is input to the calculation unit 21 and servo amplifier 23 of the robot controller 2, which will be described later.
[0019] Therefore, as shown in Figure 3, when the lower arm's first drive unit 14 rotates the first drive shaft 35 by its own driving force, the end of the first drive link 31 on the second connecting shaft 38 side swings in the front-rear direction. Then, following the movement of the first drive link 31, the end of the first driven link 33 on the third connecting shaft 39 side swings in the front-rear direction, and the second driven link 34 moves mainly in the front-rear direction. Then, the upper arm structure 12 moves mainly in the front-rear direction, and the hand 8 moves mainly in the front-rear direction. Also, as shown in Figure 4, when the lower arm's second drive unit 15 rotates the second drive shaft 36 by its own driving force, the end of the second drive link 32 on the first connecting shaft 37 side swings in the up-down direction. Then, following the second drive link 32, the second driven link 34 swings around the second connecting shaft 38. Then, the upper arm structure 12 rotates around the second connecting shaft 38, and the hand 8 moves mainly in the up-down direction.
[0020] [Example of a robot controller configuration] Figure 5 is a block diagram schematically showing an example of the configuration of the control system of the robot system 100.
[0021] As shown in Figure 1, the robot controller 2, which can also be called a robot control device, is positioned around the robot body 1 and performs position control, speed control, or current control of the controlled axis of the robot body 1. As shown in Figure 5, the robot controller 2 includes, for example, a calculation unit 21 having an arithmetic unit such as a CPU, a storage unit 22 having memory such as ROM and RAM, and a plurality of servo amplifiers 23 provided corresponding to the servo motors of the lower arm first drive unit 14, the lower arm second drive unit 15, and the joint drive unit 13. The robot controller 2 also estimates the amount of deflection δ of the link structure 11, that is, the amount of displacement of the position and orientation of the second driven link 34 relative to the support link 30 due to the deflection of the link structure 11. The robot controller 2 may consist of a single controller that performs centralized control, or it may consist of a plurality of controllers that cooperate with each other to perform distributed control.
[0022] The calculation 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 realized by the calculation unit 21 executing a predetermined control program stored in the storage unit 22. The storage unit 22 stores at least one predetermined control program, and the operation of the robot body 1 is controlled by the calculation unit 21 reading and executing the control program. The storage unit 22 also stores a stiffness value determination function, which will be described later.
[0023] The deflection estimation device is a device that estimates the amount of dynamic deflection of the link structure 11 due to the dynamic load generated by the acceleration and deceleration of the robot arm 7 when the robot arm 7 is operated. Specifically, the deflection estimation device is a device that estimates the displacement of the position and orientation of the distal end of the link structure 11 relative to the support link 30, i.e., the second driven link 34.
[0024] The servo amplifier 23 controls the corresponding servo motor. Specifically, in position control, for example, the servo amplifier 23 performs tracking control of the servo motor so that the deviation between the current position and the angular position of the output shaft of the servo motor, which is determined based on the position command value generated by the command generation unit 29, becomes zero.
[0025] [Example of operation] Next, we will explain an example of the operation related to the deflection amount estimation operation of the robot system 100.
[0026] Figure 6 is a flowchart showing an example of the operation related to the deflection amount estimation operation of the robot system 100.
[0027] First, in step S1, the opening angle calculation unit 25 calculates the opening angle θ, which is the angle between the first drive link 31, one of the links in the link structure 11 that rotates around a reference axis formed by the first drive shaft 35 and the second drive shaft 36, which are the axes of rotational pair of the link structure 11, and the second drive link 32, the other link in the link structure 11 that rotates around the reference axis. Specifically, the opening angle calculation unit 25 calculates the opening angle θ, which is the angle between 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 that drives the first drive link 31 and the angular position information of the output shaft of the servo motor that drives the second drive link 32. The angular position information of the output shaft of the servo motor that drives the first drive link 31 is detected by the encoder 14a of the lower arm first drive unit 14, and the angular position information of the output shaft of the servo motor that drives the second drive link 32 is detected by the encoder 15a of the lower arm second drive unit 15. The angle formed by the two links connected in the first connecting shaft 37, the second connecting shaft 38, or the third connecting shaft 39 may be defined as the open angle.
[0028] Next, in step S3, the load calculation unit 26 calculates the load received by the link structure 11. In this embodiment, the load received by the link structure 11 is the dynamic load received by the link structure 11 due to the acceleration and deceleration of the link during the operation of the robot arm 7. The load calculation unit 26 handles the load amount with a sign, for example, treating it as a positive load generated by accelerating the link when the swing of the robot arm 7 begins, and a negative load generated by decelerating the link when the swing ends.
[0029] Next, in step S5, the stiffness matrix determination unit 27 determines the stiffness value, which is the value of each component of the stiffness matrix C (rigidity matrix, stiffness matrix) corresponding to the opening angle θ. The stiffness matrix C is a 6×6 symmetric matrix relating the load w received by the link structure 11 and the amount of deflection δ of the link structure 11, and is shown in the following equation (1) c 11 ~c 66 It has 36 components. The load w is a force in six directions of force and moment, and is a wrench.
[0030]
number
[0031] The stiffness matrix determination unit 27 is c 11 ~c 66 The stiffness value is determined using a stiffness value determination function that is defined individually for each of the 36 components. 11 ~c 66 Removing the symmetric component from the 36 components leaves 21 components.
[0032] The stiffness value determination function is a function that represents the correlation between the stiffness value and the opening angle θ of the link structure 11, and is calculated by analysis using the finite element method (FEM). Specifically, first, stiffness values corresponding to several different opening angles θ are obtained in advance through analysis. For the first drive link 31, the angle when it is extending vertically is set to 0°, the forward tilt is set to positive, and the backward tilt is set to negative. For the second drive link 32, the angle when it is extending horizontally is set to 0°, the upward tilt is set to negative, and the backward tilt is set to positive. The sum of the angles of the first drive link 31 and the second drive link 32 is then taken as the opening angle θ. For example, stiffness values are obtained for each of the opening angles θ such as -66°, -44°, -22°, 0°, 22°, 44°, and 66°. Then, the stiffness values corresponding to the multiple opening angles θ obtained through analysis are linearly interpolated. The linearly interpolated function is then taken as the stiffness value determination function. Figure 7 shows c 36 An example of a stiffness value determination function related to the components is shown. Also, Figure 8 shows c 13 An example of a stiffness value determination function related to the components is shown. Furthermore, the sampling interval for obtaining stiffness values using the finite element method is set so that the trend of change in stiffness values is revealed by linear interpolation. As shown in Figures 7 and 8, for example, by obtaining stiffness values at 22° intervals, the trend of change in stiffness values can be obtained.
[0033] 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 related to the following equation (2).
[0034]
number
[0035] Incidentally, in a serial link, the relationship between the load w and the deflection amount δ usually has linearity. However, in the link structure, as shown in FIGS. 7 and 8, the relationship between the load w and the deflection amount δ has non-linearity, and the stiffness matrix C has stiffness values with different change tendencies according to the opening angle θ as components. Therefore, it has been difficult to estimate the deflection amount δ. However, the deflection amount estimation device of the robot system 100 uses the stiffness matrix C having the stiffness values c 11 ~c 66 as components to quickly estimate the deflection amount δ of the link structure. Therefore, for example, compared with the case of simultaneously solving the equations representing the relationship between the load w and the deflection amount δ of each link, the amount of calculation can be reduced, and the deflection amount δ can be quickly calculated. Thus, the operating speed of the robot body 1 can be improved. Note that, as shown in Equation (2), in the estimation of the dynamic deflection amount δ, the influence of the gravity component is minor, so the influence of the gravity component is ignored.
[0036] Next, in step S7, the command generation unit 29 generates a command value based on the operation 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 unit 11 calculated by the deflection amount calculation unit 28. The compensation amount is an amount proportional to the acceleration of the link structure unit 11, and the compensation amount at the start of swinging and the compensation amount at the end of the operation have opposite signs. Thus, the vibration of robot arm 7 accompanying the acceleration and deceleration of robot arm 7 can be suppressed.
[0037] As described above, the deflection amount estimation device uses the stiffness matrix C having the stiffness values c 11 ~c 66 as components to quickly estimate the deflection amount δ of the two-degree-of-freedom link structure. Therefore, the amount of calculation can be reduced, and the deflection amount δ can be quickly calculated. Thus, the operating speed of the robot body 1 can be improved.
[0038] <Modified Example> In the above embodiment, the deflection amount estimation device estimated the dynamic deflection amount δ. Instead of estimating the dynamic deflection amount δ, the deflection amount estimation device may have a load calculation unit 26 calculate the static load, and a deflection amount calculation unit 28 estimate the static deflection amount based on the relationship between the static load and the static deflection amount.
[0039] Furthermore, in the above embodiment, the first joint axis JT1 connects the lower arm structure and the base 6 so as to be rotatable around a pivot axis extending in the vertical direction. Alternatively, as shown in Figure 9, the first joint JT1 may connect the lower arm structure and the base 6 so as to be rotatable around a bend axis extending in the horizontal direction. Even if the bending operation of the first joint JT1 changes the posture of the lower arm structure relative to the ground surface of the base 6 and the robot body 1, the robot system 100 can estimate the amount of deflection δ of the link structure 11.
[0040] From the above description, many improvements and 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 for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The structural and / or functional details described above can be substantially modified without departing from the spirit of the invention.
[0041] (Enumeration of embodiments) Embodiment 1: A deflection amount estimation device for estimating the deflection amount δ of a link structure 11 of a robot arm 7, which is made up of multiple links connected by joints, including a link structure 11 with two degrees of freedom having multiple rotational pairs, An opening angle calculation unit 25 calculates the opening angle θ, which is the angle formed between one link 31 of the link structure 11 that rotates around a reference axis which is the axis of rotation of one of the link structure parts 11, and the other link 32 of the link structure 11 that rotates around the reference axis. A load calculation unit 26 calculates the load that the link structure 11 receives, Each component c of the stiffness matrix C relates the load on the link structure 11 to the amount of deflection δ of the link structure 11. 11 ~c 66The 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, using a stiffness value determination function that represents the correlation between the stiffness value, which is a value of , and the opening angle θ of the link structure 11. 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 11 ~c 66 A deflection estimation device comprising: a deflection amount calculation unit 28 that calculates the deflection amount δ of the link structure 11 based on a stiffness matrix C having the following components. According to Embodiment 1, the amount of deflection δ of the link structure 11 can be estimated. Furthermore, since the link structure 11 can be given multiple degrees of freedom, the structure of the distal end of the link structure 11 of the robot arm 7 can be simplified. In addition, the stiffness value c is determined based on the opening angle θ. 11 ~c 66 By using a stiffness matrix C having the following components, the amount of deflection δ of the link structure 11 can be quickly estimated. Therefore, the amount of computation required in the process of calculating the amount of deflection δ can be reduced, and the amount of deflection δ can be calculated quickly.
[0042] Embodiment 2: The deflection amount estimation device according to Embodiment 1, wherein the link structure 11 is a five-bar closed-loop link. According to Embodiment 2, the amount of deflection δ of the five-bar link in the closed-loop structure can be calculated quickly.
[0043] Embodiment 3: The link structure 11 includes a first drive link 31 which is one link, a second drive link 32 which is another link, a first driven link 33, a second driven link 34, a first drive shaft 35 which rotatably supports the first drive link 31 around a reference axis, a second drive shaft 36 which rotatably supports the second drive link 32 around a reference axis, a first connecting shaft 37 which rotatably connects the second drive link 32 and the first driven link 33, a second connecting shaft 38 which rotatably connects the first drive link 31 and the second driven link 34, and a third connecting shaft 39 which rotatably connects the first driven link 33 and the second driven link 34. The deflection amount estimation device according to Embodiment 1 or 2 further comprises a first drive unit 14 that drives a first drive link 31 to swing around a first drive shaft 35, and a second drive unit 15 that drives a second drive link 32 to swing around a second drive shaft 36. According to Embodiment 3, 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.
[0044] Embodiment 4: The link structure 11 further includes a support link 30, The first drive shaft 35 connects the support link 30 and the first drive link 31 so that they can rotate around a reference axis. The deflection amount estimation device according to Embodiment 3, wherein 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.
[0045] Embodiment 5: 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. 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. The deflection amount estimation device according to Embodiment 3, wherein 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. According to Embodiment 5, the amount of deflection δ of the link structure 11 can be estimated more accurately.
[0046] Embodiment 6: A deflection amount estimation device according to any one embodiment of Embodiments 1 to 3, wherein the stiffness value determination function is a function obtained by linearly interpolating the stiffness values corresponding to the multiple opening angles θ obtained by analysis, after obtaining stiffness values corresponding to the multiple opening angles θ obtained by analysis in advance. According to Embodiment 6, the amount of computation required in the process of calculating the deflection amount δ can be reduced, and the deflection amount δ can be calculated quickly.
[0047] Embodiment 7: A memory containing at least one program, A deflection estimation device comprising: a processor that calculates the estimated deflection of a link structure 11 of a robot arm 7, which is made up of multiple links connected by joints, including a link structure 11 with two degrees of freedom having multiple rotational pairs, by executing at least one program, The processor is An opening angle calculation process calculates the opening angle, which is the angle formed between one link of the link structure 11 that rotates around a reference axis, which is the axis of rotation of one of the link structure 11, and another link of the link structure 11 that rotates around the reference axis. A load calculation process that calculates the load received by the link structure 11, Each component c of the stiffness matrix relating the load on the link structure 11 and the amount of deflection of the link structure 11 11 ~c 66 A stiffness matrix determination process is performed to determine the stiffness value corresponding to the opening angle θ of the link structure 11 calculated in the opening angle calculation process, using a stiffness value determination function that represents the correlation between the stiffness value, which is the value of , and the opening angle θ of the link structure 11. 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 11 ~c 66 A deflection estimation device that performs a deflection calculation process to calculate the deflection amount δ of the link structure 11 based on a stiffness matrix C having the following components. According to Embodiment 7, the amount of deflection δ of the link structure 11 can be estimated. Furthermore, since the link structure 11 can be given multiple degrees of freedom, the structure of the robot arm can be simplified. In addition, the stiffness value c is determined based on the opening angle θ. 11 ~c 66 By using a stiffness matrix C having the following components, the amount of deflection δ of the link structure 11 can be quickly estimated. Therefore, the amount of computation required in the process of calculating the amount of deflection δ can be reduced, and the amount of deflection δ can be calculated quickly.
[0048] Embodiment 8: A robot control device comprising a deflection amount estimation device described in any one embodiment of Embodiments 1 to 7. According to Embodiment 8, the stiffness value c is determined based on the opening angle θ. 11 ~c 66 By using a stiffness matrix C having the following components, the amount of deflection δ of the link structure 11 can be quickly estimated. Therefore, the amount of computation can be reduced, and the amount of deflection δ can be calculated quickly. Thus, the operating speed of the robot body 1 can be improved.
[0049] Embodiment 9: A method for estimating the amount of deflection δ of a link structure 11 of a robot arm 7, which is formed by a plurality of links connected by joints, including a link structure 11 with two degrees of freedom having a plurality of rotational pairs, The opening angle θ is calculated, which is the angle formed between one link 31 of the link structure 11, which rotates around the reference axis which is the axis of rotation of one of the link structure parts 11, and the other link 32 of the link structure 11, which rotates around the reference axis. The load on the link structure 11 is calculated, Using a stiffness value determination function that represents the correlation between the stiffness values, which are the values of each component of the stiffness matrix C relating the load on the link structure 11 and the amount of deflection δ of the link structure 11, and the opening angle θ of the link structure 11, the stiffness value corresponding to the calculated opening angle θ of the link structure 11 is determined. The calculated load on the link structure 11 and the determined stiffness value c 11 ~c 66 A method for estimating deflection, which calculates the amount of deflection δ of the link structure 11 based on a stiffness matrix C having the following components. According to Embodiment 9, the amount of deflection δ of the link structure 11 can be estimated. Furthermore, since the link structure 11 can be given multiple degrees of freedom, the structure of the robot arm can be simplified. In addition, the stiffness value c is determined based on the opening angle θ. 11 ~c 66 By using a stiffness matrix C having the following components, the amount of deflection δ of the link structure 11 can be quickly estimated. Therefore, the amount of computation required in the process of calculating the amount of deflection δ can be reduced, and the amount of deflection δ can be calculated quickly. [Explanation of Symbols]
[0050] 1. Robot body 2 Robot Controller 6 bases 7. Robot Arm 8 Hands 11 Link structure 12 Upper arm structure 13. Joint drive unit 13a encoder 14 Lower arm first drive unit 14a encoder 15 Lower arm second drive unit 15a encoder 21 Arithmetic section 22 Memory section 23 Servo Amplifier 25. Opening Angle Calculation Section 26 Load Calculation Unit 27 Stiffness matrix determination section 28 Deflection Amount Calculation Unit 29 Command generation section 30 Supporting Links 31 First drive link 32 Second drive link 33. First Dependent Link 34 Second Dependent Link 35 First drive shaft 36. Second drive shaft 37 1st connection shaft 38 2nd connection shaft 39 3rd connection shaft 100 Robot Systems
Claims
1. A deflection amount estimation device for estimating the deflection amount of a link structure of a robot arm, which is made up of multiple links connected by joints, including a link structure with two degrees of freedom having multiple rotational pairs, An opening angle calculation unit calculates the opening angle, which is the angle formed by one link of the link structure that rotates around a reference axis which is the axis of rotation of one of the link structure parts, and another link of the link structure that rotates around the reference axis. A load calculation unit that calculates the load received by the link structure, A stiffness matrix determination unit determines the stiffness value corresponding to the opening angle of the link structure calculated by the opening angle calculation unit, using a stiffness value determination function that represents the correlation between the stiffness value, which is the value of each component of the stiffness matrix relating the load received by the link structure and the amount of deflection of the link structure, and the opening angle of the link structure. A deflection amount estimation device comprising: a load calculation unit that calculates the amount of deflection of the link structure based on the load received by the link structure calculated by the load calculation unit and the stiffness matrix having the stiffness value determined by the stiffness matrix determination unit as a component.
2. The deflection amount estimation device according to claim 1, wherein the link structure is a five-bar closed-loop link.
3. The link structure comprises a first drive link which is the first link, a second drive link which is the other link, a first driven link, a second driven link, a first drive shaft which supports the first drive link so as to be rotatable around the reference axis, a second drive shaft which supports the second drive link so as to be rotatable around the reference axis, a first connecting shaft which rotatably connects the second drive link and the first driven link, a second connecting shaft which rotatably connects the first drive link and the second driven link, and a third connecting shaft which rotatably connects the first driven link and the second driven link. The deflection amount estimation device according to claim 1, further comprising: a first drive unit that drives the first drive link to swing around the first drive shaft; and a second drive unit that drives the second drive link to swing around the second drive shaft.
4. The aforementioned link structure further comprises a support link, The first drive shaft connects the support link and the first drive link so that they can rotate around the reference axis, The deflection amount estimation device according to claim 3, wherein the second drive shaft connects the support link and the second drive link so as to be rotatable around the reference axis.
5. 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 deflection amount estimation device according to claim 3, wherein 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 estimation device according to claim 1, wherein the stiffness value determination function is a function obtained by linearly interpolating the stiffness values corresponding to a plurality of different opening angles obtained by analysis in advance.
7. Memory containing at least one program, A deflection estimation device comprising: a processor that calculates the estimated deflection of a link structure of a robot arm, in which a plurality of links, including a link structure with two degrees of freedom having a plurality of rotational pairs, are connected by joints, by the execution of at least one program, The aforementioned processor, An opening angle calculation process that calculates the opening angle, which is the angle formed between one link of the link structure that rotates around a reference axis which is the axis of rotation of one of the link structure parts, and another link of the link structure that rotates around the reference axis. A load calculation process for calculating the load received by the link structure, A stiffness matrix determination process determines the stiffness value corresponding to the opening angle of the link structure calculated in the opening angle calculation process, using a stiffness value determination function that represents the correlation between the stiffness value, which is the value of each component of the stiffness matrix relating the load received by the link structure and the amount of deflection of the link structure, and the opening angle of the link structure. A deflection amount estimation device that performs a deflection amount calculation process to calculate the amount of deflection of the link structure based on the load received by the link structure calculated in the load calculation process and the stiffness matrix having the stiffness value determined in the stiffness matrix determination process as a component.
8. A robot control device comprising the deflection amount estimation device according to any one of claims 1 to 7.
9. A method for estimating the amount of deflection of a link structure in a robot arm, which is made up of multiple links connected by joints, including a link structure with two degrees of freedom having multiple rotational pairs, The opening angle is calculated, which is the angle formed by one link of the link structure that rotates around a reference axis, which is the axis of rotation of one of the link structures, and the other link of the link structure that rotates around the reference axis. The load on the aforementioned link structure is calculated, Using a stiffness value determination function that represents the correlation between the stiffness value, which is the value of each component of the stiffness matrix relating the load received by the link structure and the amount of deflection of the link structure, and the opening angle of the link structure, the stiffness value corresponding to the opening angle of the calculated link structure is determined. A method for estimating deflection, which calculates the amount of deflection of the link structure based on the calculated load on the link structure and the stiffness matrix having the determined stiffness value as a component.