Damage estimation device and damage estimation method

Abstract

Provided is a damage estimation device capable of more accurately extracting a place where damage is likely to occur in a linear motion guide mechanism for a robot. The damage estimation device (30) includes a data acquisition unit (31) that acquires a physical parameter related to the motion of each axis of a robot (10) and an external force acting on the robot (10) at each time when an action program of the robot (10) is executed; an external force and moment calculation unit (32) that calculates an external force and moment acting on a reference position of a sliding member at the each time; a load calculation unit (33) that calculates a load acting on the sliding member at the each time; an equivalent load calculation unit (34) that calculates an equivalent load of the sliding member at the each time; a damage estimation value calculation unit (35) that calculates a damage estimation value of the sliding member at the each time; and an estimated damage place extraction unit (36) that extracts an estimated damage place of the linear motion guide mechanism.

Description

TECHNICAL FIELD

[0001] The present application relates to a damage estimation device and a damage estimation method. BACKGROUND

[0002] In the past, as an inspection of a linear motion guide mechanism for a robot, the state of a sliding member, a guide rail, and lubricating oil is confirmed visually. However, in the linear motion guide mechanism, since a rolling surface or a rolling body of the sliding member is located inside, it is difficult to directly inspect. Although an inspection of a rolling surface of the guide rail is also performed instead of an inspection of the rolling surface or the rolling body of the sliding member, in this case, the inspection needs to be performed over the entire length of the guide rail, and thus a large amount of working hours is required. In particular, in a general linear motion guide mechanism, since there are four rolling surfaces, for a portion that cannot be seen from above, it becomes necessary to confirm using a mirror or the like, and thus labor and time are spent on the work. In addition, in a case where a sliding member is provided on the sliding member, for a rolling surface of the guide rail located directly below the sliding member, the inspection needs to be performed while moving the sliding member together with the sliding member, and thus the working hours increase.

[0003] On the other hand, there has been proposed a recovery method in which, in a robot having a linear motion guide mechanism, in a case where the linear motion guide mechanism has failed, a displacement of a linear motion bearing is measured, a load applied to the linear motion bearing is calculated on the basis of the measured displacement, and a linear motion bearing having a rigidity suitable for the load is selected to be replaced with the linear motion bearing that has failed (for example, refer to Patent Literature 1).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2012-13469 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] As a situation unique to a robot for industry, sometimes the center of gravity position changes in accordance with a change in posture, or a load changes due to a movement pattern when a movement program is executed. Therefore, in a linear motion guide mechanism provided in the robot, it is difficult to accurately calculate a load applied at a certain instant. This is the same not only for the linear motion guide mechanism provided in the robot, but also for a linear motion guide mechanism of a tool provided in the robot, or a linear motion guide mechanism that cooperates with the robot.

[0009] An object of the present application is to provide a damage estimation device and a damage estimation method capable of more accurately extracting a place where damage is likely to occur in a linear motion guide mechanism for a robot.

[0010] Solution for solving the problem

[0011] One embodiment of the present disclosure is a damage estimation device that estimates a damage location of a linear motion guide mechanism for a robot, the linear motion guide mechanism including one or more sliders configured to move linearly on a guide rail and a sliding member provided to the slider, the damage estimation device including: a data acquisition unit configured to acquire physical parameters related to movement of each axis of the robot and external forces acting on the robot at each time when an operation program of the robot is executed; an external force and torque calculation unit configured to calculate external forces and torques acting on a reference position of the sliding member at each time based on the physical parameters related to movement of each axis of the robot and the external forces acting on the robot acquired by the data acquisition unit and a geometric parameter; a load calculation unit configured to calculate loads acting on the slider at each time based on the external forces and torques acting on the reference position calculated by the external force and torque calculation unit and a distance from the reference position of the sliding member to a center of gravity position of the slider; an equivalent load calculation unit configured to calculate equivalent loads of the slider at each time based on the loads acting on the slider at each time calculated by the load calculation unit and a calculation formula of the equivalent loads; a damage estimation value calculation unit configured to calculate damage estimation values of the slider at each time based on the equivalent loads of the slider at each time calculated by the equivalent load calculation unit and safety estimation elements; and a damage location extraction unit configured to extract an estimated damage location of the linear motion guide mechanism based on the damage estimation values of the slider at each time calculated by the damage estimation value calculation unit and positions of the slider on the guide rail at each time.

[0012] Another aspect of the present disclosure is a damage location estimation method for extracting an estimated damage location of a linear motion guide mechanism provided to a robot or a linear motion guide mechanism that cooperates with the robot, and a damage location estimation device for estimating a damage location of a linear motion guide mechanism for a robot, the linear motion guide mechanism including one or more sliders configured to linearly move freely on a guide rail and a sliding member provided to the slider, the damage location estimation method including: a data acquisition step of acquiring physical parameters related to the motion of each axis of the robot and external forces acting on the robot at each time when an operation program of the robot is executed; an external force and torque calculation step of calculating external forces and torques acting on a reference position of the sliding member at each time based on the physical parameters related to the motion of each axis of the robot and the external forces acting on the robot acquired by the data acquisition step, and a geometric parameter; a load calculation step of calculating loads acting on the slider at each time based on the external forces and torques acting on the reference position calculated by the external force and torque calculation step, and a distance from the reference position of the sliding member to a center of gravity position of the slider; an equivalent load calculation step of calculating equivalent loads of the slider at each time based on the loads acting on the slider at each time calculated by the load calculation step and a calculation formula of the equivalent loads; a damage estimation value calculation step of calculating damage estimation values of the slider at each time based on the equivalent loads of the slider at each time calculated by the equivalent load calculation step and a safety estimation element; and an estimated damage location extraction step of extracting an estimated damage location of the linear motion guide mechanism based on the damage estimation values of the slider at each time calculated by the damage estimation value calculation step and a position of the slider on the guide rail at each time.

[0013] Effects of the Invention

[0014] According to the damage location estimation device and the damage location estimation method according to the present disclosure, a location where damage is likely to occur can be more accurately extracted in a linear motion guide mechanism for a robot. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a diagram showing the overall configuration of a robot system 1 according to a first embodiment.

[0016] Figure 2A FIG. 3 is a conceptual diagram showing a damage location estimation device 30 provided to the robot 10.

[0017] Figure 2B FIG. 3 is a conceptual diagram showing a damage location estimation device 30 provided to the robot 10.

[0018] Figure 2C This is a conceptual diagram of a linear motion guidance mechanism 100 that collaborates with robot 10.

[0019] Figure 3 This is a perspective view showing a specific example of a linear motion guiding mechanism 100.

[0020] Figure 4 yes Figure 3 The xy section view of the guide rail 110 and the slider 120 is shown.

[0021] Figure 5 This is a top view of the linear motion guide mechanism 100.

[0022] Figure 6 This diagram illustrates the process of extracting the estimated damage point of the linear motion guide mechanism 100 in the estimated damage point extraction section 36.

[0023] Figure 7 This is a flowchart illustrating the process of the damage estimation extraction procedure executed in the damage estimation device 30.

[0024] Figure 8 This is an overall structural diagram of the robot system 1A according to the second embodiment.

[0025] Figure 9 This is a graph illustrating the relationship between the load P acting on the slider 120 and the life E of the slider 120.

[0026] Figure 10 This diagram illustrates the process of extracting the estimated damage point of the linear motion guide mechanism 100 in the estimated damage point extraction section 36A.

[0027] Figure 11 This is a flowchart illustrating the process of the damage estimation extraction procedure executed in the damage estimation device 30A. Detailed Implementation

[0028] The following describes embodiments of the damage estimation device and method according to the present invention. Furthermore, the accompanying drawings are schematic diagrams, and the shapes, scales, and aspect ratios of the parts may be altered or exaggerated relative to the actual object for ease of understanding. Additionally, shaded lines representing cross-sections of components are appropriately omitted in the drawings.

[0029] In this specification, terms used to describe shapes, geometric conditions, and the degree to which they are determined, such as “parallel,” “orthogonal,” and “direction,” include, in addition to their strict meaning, a range of degrees to which they are considered almost parallel or almost orthogonal, and a range of degrees to which they are roughly considered to be in that direction.

[0030] (First Implementation)

[0031] Figure 1 is a whole configuration view of the robot system 1 of the first embodiment. Figure 2A and Figure 2B is a conceptual view showing the damage estimation device 30 provided to the robot 10. Figure 2C is a conceptual view of a linear motion guide mechanism 100 that cooperates with the robot 10. Figure 3 is a perspective view showing a specific example of the linear motion guide mechanism 100. Figure 4 is Figure 3 is an x-y sectional view of the guide rail 110 and the slider 120 shown in Figure 5 is a plan view of the linear motion guide mechanism 100.

[0032] As shown in Figure 1 , the robot system 1 is provided with the robot 10, the robot control device 20, and the damage estimation device 30. In the robot system 1, the robot 10 and the robot control device 20 and the robot control device 20 and the damage estimation device 30 are electrically connected by signal cables (not shown) respectively. Further, the structure of the robot 10 and the robot control device 20 in the first embodiment is the same in the robot system 1A of the second embodiment described later.

[0033] (Robot 10)

[0034] The robot 10 is a device that performs a work such as processing, assembling, welding, or the like of a component based on the control of the robot control device 20 (described later). The robot 10 performs an action mode corresponding to the work described above by driving a servo motor (not shown) that causes each part to act based on an action instruction transmitted from the robot control device 20. The robot 10 is provided with the linear motion guide mechanism 100 (described later). As shown in Figures 2A-2C , the linear motion guide mechanism 100 is a device that moves the arm 11 Figure 2A , the tool 12 Figure 2B , or the robot 10 Figure 2C linearly in the direction of the guide rail 110. As shown in Figures 2A-2C , the linear motion guide mechanism 100 is provided to the robot 10 and is also provided to cooperate with the robot 10.

[0035] Figure 2A The linear motion guide mechanism 100 shown in Figure 2A is provided to the main body of the robot 10 to linearly move the arm 11. In the case of the mode shown in Figure 3 , since each part of the robot 10 acts like a pendulum, the ratio of the load caused by the inertial force at the time of the action of each part of the robot 10 becomes large as the load acting on the slider 120 (refer to ).

[0036] Figure 2B The linear motion guide mechanism 100 shown is provided to a tool 12 held by an arm 11 of a robot 10. In Figure 2B In the case of the manner shown, since each part of the robot 10 moves like a pendulum, the ratio of the load due to the inertial force at the time of movement of each part of the robot 10 and the load due to gravity (the weight of the tool 12) as the load acting on the sliding member 120 becomes large.

[0037] Figure 2C The linear motion guide mechanism 100 shown is provided to a tool 12 held by an arm 11 of a robot 10. In Figure 2C In the case of the manner shown, the ratio of the load due to gravity (the weight of the robot 10) as the load acting on the sliding member 120 becomes large.

[0038] Further, in the present specification, the robot 10 in the manner shown in Figure 2A and Figure 2B the system using the robot 10 shown in Figure 2C are collectively referred to as "robot 10".

[0039] In Figures 2A-2C , the arrow A indicates the direction (the direction of the linear motion axis) in which the sliding member 130 or the guide rail 110 (refer to Figure 3 ) moves in the linear motion guide mechanism 100. In the linear motion guide mechanism 100, in the case where, for example, a ball screw and a motor are mainly used to constitute the drive portion of the sliding member 130, the axis direction of the ball screw becomes the direction of the linear motion axis. In the present embodiment, although the case where the linear motion guide mechanism 100 is provided in the main body of the robot 10 as shown in Figure 2A is described as an example, the manner of the robot 10 and the linear motion guide mechanism 100 can also be the manner shown in Figure 2B or Figure 2C .

[0040] As shown in Figure 3 , the linear motion guide mechanism 100 of the present embodiment has two guide rails 110, four sliding members 120, and a sliding member 130. The guide rail 110 is a member that linearly guides the movement of the sliding member 120 in the extension direction. The two guide rails 110 are arranged in parallel with their respective extension directions (z direction) at equal intervals in the width direction (y direction). As shown in Figure 4 , in the guide rail 110, bearings 111 are provided at four places. Each bearing 111 is provided along the extension direction of the guide rail 110.

[0041] On the two rails 110, two sliders 120 are respectively installed along the extending direction. As shown in Figure 4 , the slider 120 is a member having a substantially concave shape in cross section. Bearings 121 are provided at four places on the inner side. Between the bearings 121 of the slider 120 and the bearings 111 of the rail 110, a plurality of rolling bodies 140 are embedded in a ring shape.

[0042] The sliding member 130 is a plate-shaped member for installation of the arm 11 (refer to Figure 2A ) of the robot 10, a tool 12 (refer to Figure 2B ) held by the arm 11 of the robot 10, or the robot 10 (refer to Figure 2C ). The sliding member 130 is installed on the four sliders 120. Specifically, as shown in Figure 5 , the sliding member 130 is installed on the sliders 120 disposed at the lower part of each of the four corners in plan view.

[0043] (Robot control device 20)

[0044] The robot control device 20 is a device that controls the robot 10 to cause the robot 10 to perform a prescribed work. As shown in Figure 1 , the robot control device 20 includes a control section 21, an operation input section 22, a display section 23, and a storage section 24.

[0045] The control section 21 is a unit that uniformly controls the movement of the robot 10 and is constituted by a microprocessor including a CPU (Central Processing Unit), a memory, and the like. The control section 21 is provided with a movement program that describes each movement of the robot 10. The control section 21 creates a movement instruction based on the provided movement program, the movement instruction including, for example, a movement instruction to a servo motor that drives a linear motion shaft, and the like. Furthermore, the created movement instruction is transmitted to the robot 10 via a signal cable (not shown), thereby controlling the movement of the robot 10. Thus, a prescribed work performed by the robot 10 is executed.

[0046] The operation input section 22 is a device that acquires various numerical data, operation instructions, movement instructions, and the like input by an operator of the robot 10. The operation input section 22 is constituted by, for example, a keyboard, a mouse, a touch panel, and the like (not shown). Various numerical data and the like input from the operation input section 22 are stored in, for example, the storage section 24.

[0047] The display section 23 is a display device capable of displaying various data, messages, graphics, and the like.

[0048] The storage section 24 is a storage device mainly storing various programs, data, and the like executed by the control section 21. The storage section 24 is constituted by, for example, a semiconductor memory, a hard disk device, and the like.

[0049] (broken part estimation device 30)

[0050] The broken part estimation device 30 is a device that extracts an estimated broken part of the linear motion guide mechanism 100 (refer to FIG. 1) provided to the robot 10. In the broken part estimation device 30, a data acquisition section 31, an external force and torque calculation section 32, a load calculation section 33, an equivalent load calculation section 34, a safety factor calculation section 35, and a broken part estimation extraction section 36 described later are constituted by a microprocessor including a CPU (Central Processing Unit), a memory, and the like. The microprocessor cooperates with each hardware by reading and executing a system program, an application program, and the like stored in the memory, thereby performing an estimation process of a broken part described later. Figure 2A

[0051] The broken part estimation device 30 includes the data acquisition section 31, the external force and torque calculation section 32, the load calculation section 33, the equivalent load calculation section 34, the safety factor calculation section 35, the broken part estimation extraction section 36, a display section (position information output section) 37, and a storage section 38. In addition, a part or all of the functions of the data acquisition section 31, the external force and torque calculation section 32, the load calculation section 33, the equivalent load calculation section 34, the safety factor calculation section 35, and the broken part estimation extraction section 36 can be executed by the control section 21 of the robot control device 20.

[0052] The data acquisition section 31 acquires, via the robot control device 20, a physical parameter related to the movement of each axis of the robot 10 and an external force acting on the robot 10 at each time t when an operation program of the robot 10 is executed. Specifically, the data acquisition section 31 acquires the position, the speed, and the acceleration of each axis of the robot 10 as the physical parameter related to the movement of each axis of the robot 10. In addition, the data acquisition section 31 acquires, for example, the posture of each axis of the robot 10, the movement amount of each axis with respect to a reference position, and the like in addition to the position, the speed, and the acceleration of each axis of the robot 10.

[0053] Here, the operation program is a program executed in the robot control device 20 or a simulation device (not shown) of the robot 10, and is a program for causing the robot 10 to perform a prescribed work. In addition, the external force acting on the robot 10 is a difference between a calculated value of a torque required to perform each operation of the robot 10 and a measured value of a torque actually required when the robot 10 is actually operated. The external force acting on the robot 10 can be calculated, for example, from a command value of a current supplied to a servo motor (not shown) that drives each part of the robot 10 and an actual current value when the servo motor is actually operated.

[0054] ​The external force and torque calculation unit 32 calculates the external force and torque acting on the reference position S0 of the sliding member 130 at each time t based on the position, velocity, acceleration of each axis of the robot 10, the external force acting on the robot 10, and the geometric parameters acquired by the data acquisition unit 31. Specifically, the external force and torque calculation unit 32 calculates as follows: Figure 3 As shown, the external forces and moments about each of the three orthogonal coordinate axes x, y, and z are set at the reference position S0 of the sliding member 130. Furthermore, the reference position S0 of the sliding member 130 refers to, for example, the position of the center of gravity of the sliding member 130. Additionally, geometric parameters refer to parameters related to, for example, the link length or arm weight of the robot 10.

[0055] The load calculation unit 33 calculates the external force and torque acting on the reference position S0 based on the external force and torque calculation unit 32, and the distances L1, L2, L3, L4 from the reference position S0 of the sliding member 130 to the center of gravity positions S1, S2, S3, S4 of each sliding member 120 (refer to...). Figure 5 The load calculation unit 33 calculates the load P acting on each sliding member 120 at each time t. Specifically, the load calculation unit 33 calculates the load P. Rn and load P Tn As a load acting on each sliding member 120, such as Figure 4 As shown, the load P Rn The load P is the load on the slider 120 in the height direction (x direction) orthogonal to the extension direction of the guide rail 110. Tn This is the load in the width direction (y direction) of the slider 120. Furthermore, the load P... Rn P Tn The "n" in the designation represents any one of the four (n = 1 to 4) sliders 120. That is, the load calculation unit 33 calculates the load P acting in two directions on each of the four sliders 120 at each time t. Rn and P Tn .

[0056] The equivalent load calculation unit 34 calculates the load P acting on each sliding member 120 at each time t based on the load calculation unit 33. Rn and P Tn The equivalent load calculation unit 34 calculates the equivalent load of each sliding member 120 at each time t using the formula for calculating the equivalent load. Specifically, the equivalent load calculation unit 34 calculates the load P in two directions for each sliding member 120. Rn and P Tn The equivalent load P of each sliding member 120 at each time t is calculated using the following formula (1) as the calculation formula for the equivalent load. En .

[0057] P En = Kx P Rn + Ky P Tn … (1)

[0058] In formula (1), Kx, Ky are equivalent coefficients inherent to the linear motion guide mechanism 100.

[0059] The safety factor calculating section (breakage estimation value calculating section) 35 calculates the static safety factor (breakage estimation value) of each slide 120 at each time t based on the equivalent load P En calculated by the equivalent load calculating section 34 at each time t, and a calculation formula of the safety factor (safety estimation factor). Specifically, the safety factor calculating section 35 calculates the static safety factor F En of each slide 120 at each time t based on the equivalent load P Sn and the following formula (2) which is a calculation formula of the safety factor.

[0060] F Sn = C0 / P En … (2)

[0061] In formula (2), C0 is a basic static rated load inherent to the linear motion guide mechanism 100.

[0062] The static safety factor F Sn calculated by formula (2) is in inverse proportion to the equivalent load P En . That is, in formula (2), as the equivalent load P En becomes larger, the static safety factor F Sn becomes lower. Also, in formula (2), as the equivalent load P En becomes smaller, the static safety factor F Sn becomes higher.

[0063] The breakage estimation place extracting section 36 extracts a place where breakage is likely to occur in the linear motion guide mechanism 100 (hereinafter, also referred to as "estimated breakage place") based on the static safety factor F Sn calculated by the safety factor calculating section 35 at each time t, and the position of each slide 120 on the guide rail 110 at each time t (refer to Figure 3 ). That is, the breakage estimation place extracting section 36 extracts a place where the static safety factor F Sn is lower on the guide rail 110 as the estimated breakage place.

[0064] Next, a specific example of the process of extracting the estimated breakage place of the linear motion guide mechanism 100 in the breakage estimation place extracting section 36 will be described.

[0065] Figure 6 This diagram illustrates the process of extracting the estimated damage point of the linear motion guide mechanism 100 in the estimated damage point extraction section 36. Figure 6 This refers to 4 sliders 120 (refer to) Figure 5 The processing is performed on any of the sliders in ). Figure 6 The upper part represents the time t (horizontal axis) when the robot 10 executes its motion program, and the equivalent load P of the slider 120 at each time t. En A graph showing the relationship on the vertical axis. The equivalent load P of the sliding member 120 at each time t. En The equivalent load calculation unit 34 performs the calculation. Figure 6 The lower part is a graph showing the relationship between the time t (horizontal axis) during the execution of the robot 10's motion program and the position of the slider 120 in the z-direction of the guide rail 110 (vertical axis). The position of the slider 120 can be obtained, for example, based on the motion program executed by the robot control device 20. Furthermore, the position of the slider 120 shown on the vertical axis (z) represents the distance the slider 120 has moved relative to a reference position (0) on the guide rail 110. Figure 6 The time axis at time t is consistent in both the upper and lower charts shown.

[0066] like Figure 6 As shown in the diagram above, when the motion program is executed, the equivalent load P of the slider 120 is... En Its position on the guide rail 110 changes constantly. The estimated breakage extraction section 36 is based on the equivalent load P. En The benchmark value P EL To extract the equivalent load P En The reference value P EL The above time t. Equivalent load P En The benchmark value P EL This is a threshold calculated based on the basic static rated load C0. The equivalent load P En The reference value P EL The above time period is due to the static safety factor F Sn The load is relatively low, making it a period when damage is most likely to occur. On the other hand, the equivalent load P... En Less than the reference value P EL The time period due to the static safety factor F Sn The temperature is relatively high, making it a period when breakage is less likely. Figure 6 From the chart above, extract the equivalent load P. En The reference value P EL The above three time periods are tz1 to tz3.

[0067] The estimated extraction section 36 for the damaged area is based on the aforementioned time period tz1~tz3, andFigure 6 the lower side of the graph, the equivalent load P En as a reference value P EL The position of the slide 120 (position in the z direction on the guide rail 110) corresponding to the above time periods tz1 to tz3 is taken as the estimated damage location. In Figure 6 In the example shown, the two positions of the slide 120 farthest from the reference position (0) and the one position relatively close to the reference position are taken as the estimated damage locations (important check locations).

[0068] In addition, the estimated damage location extraction section 36 calculates the position on the guide rail 110 at which the extracted estimated damage location does not overlap the slide member 130 as the slide recommendation position data. In Figure 6 In the example shown, the position in the range corresponding to zA to zB is the slide recommendation position data. The slide recommendation position data compares, for example, the length LI of the range of the guide rail 110 in the z direction excluding the extracted estimated damage location and the length L2 of the slide member 130 (length in the z direction). Figure 3 In addition, when there is a range in which LI ≥ L2, this can be calculated by finding the positions of the start and end points of the range with respect to the reference position.

[0069] The estimated damage location extraction section 36 causes the storage section 38 (described later) to store estimated damage location data, axis position data, and slide recommendation position data, the estimated damage location data being data related to the extracted estimated damage location, the axis position data being data related to the position of each axis (all axes including linear motion axes) of the robot 10 at the time of extraction of the estimated damage location, and the slide recommendation position data being data indicating the position at which the extracted estimated damage location does not overlap the slide member 130. Furthermore, the estimated damage location extraction section 36 causes the display section 37 (described later) to display the estimated damage location data, the axis position data, and the slide recommendation position data based on an instruction of the operator input via the robot control device 20 (refer to Figure 1 ).

[0070] The display section 37 is a display device capable of displaying various data, messages, graphics, and the like. In the display section 37, the estimated damage location data, the axis position data, and the slide recommendation position data are displayed as position information.

[0071] The storage section 38 is a storage device that stores various programs, data, and the like executed by the above data acquisition section 31, the external force and moment calculation section 32, the load calculation section 33, the equivalent load calculation section 34, the safety factor calculation section 35, and the estimated damage location extraction section 36. The storage section 38 is constituted by, for example, a semiconductor memory, a hard disk device, or the like.

[0072] Next, a specific example of the process of extracting the estimated damage location of the linear motion guide mechanism 100 in the damage location estimating device 30 of the first embodiment will be described.

[0073] Figure 7 is a flowchart showing the process procedure of the damage location estimating program executed in the damage location estimating device 30. Figure 7 The process of the damage location estimating program shown is executed in synchronization with the motion program of the robot 10.

[0074] In Figure 7 In step S101, the data acquisition section 31 acquires the physical parameters related to the motion of each axis of the robot 10 (the position, velocity, and acceleration of each axis of the robot 10) and the external force acting on the robot 10 at each time t when the motion program of the robot 10 is executed (data acquisition process).

[0075] In step S102, the external force and torque calculation section 32 calculates the external force and torque acting on the reference position S0 of the sliding member 130 at each time t based on the position, velocity, and acceleration of each axis of the robot 10, the external force acting on the robot 10, and the geometric parameters acquired by the data acquisition section 31 (external force and torque calculation process).

[0076] In step S103, the load calculation section 33 calculates the load acting on each sliding member 120 at each time t based on the external force and torque acting on the reference position S0 calculated by the external force and torque calculation section 32 and the distances L1 to L4 from the reference position S0 of the sliding member 130 to the center-of-gravity positions S1 to S4 of the sliding members 120 (refer to Figure 5 ).

[0077] In step S104, the equivalent load calculation section 34 calculates the equivalent load of each sliding member 120 at each time t based on the load P Rn and P Tn acting on each sliding member 120 calculated by the load calculation section 33 and the calculation formula of the equivalent load (equivalent load calculation process).

[0078] In step S105, the safety factor calculation section 35 calculates the static safety factor of each sliding member 120 at each time t based on the equivalent load P En of each sliding member 120 calculated by the equivalent load calculation section 34 and the calculation formula of the safety factor (safety factor calculation process: damage estimate value calculation process).

[0079] In step S106, the damage location extraction section 36 extracts the damage location of each sliding member 120 at each time t based on the static safety factor F Sn of each sliding member 120 calculated by the safety factor calculation section 35 (damage location extraction process).the position of each of the sliders 120 on the guide rail 110 at each time t (refer to Figure 3 ), to extract the estimated damage site of the linear motion guide mechanism 100 (estimated damage site extraction process). After the end of step S106, the estimated damage site extraction section 36 causes the storage section 38 to store the estimated damage site data related to the extracted estimated damage site and the axis position data related to the position of each axis of the robot 10 at the time of extraction of the estimated damage site, and ends the processing of the present flowchart.

[0080] Further, the display section 37 can be caused to display the estimated damage site data, the axis position data, and the slider recommended position data, for example, based on an instruction of an operator, after the end of the processing of step S106.

[0081] The damage site estimation device 30 according to the above-described first embodiment, for example, exerts the following effects.

[0082] In the damage site estimation device 30 of the first embodiment, the position and size of a load, which is a load applied to the linear motion guide mechanism 100 when the center of gravity position changes in association with a change in posture of the robot 10 or when the load changes due to a motion pattern, are calculated, and the estimated damage site is extracted using the position and size of the load, and thus it is possible to more accurately extract the estimated damage site of the linear motion guide mechanism 100 provided to the robot 10 or the linear motion guide mechanism 100 that cooperates with the robot 10.

[0083] According to the damage site estimation device 30 of the first embodiment, it is possible to more accurately extract a site where damage is likely to occur, and thus it becomes easier to lock important inspection sites in the linear motion guide mechanism 100. Thus, by using the damage site estimation device 30 of the first embodiment, it is possible to reduce the man-hours required for inspection work of the linear motion guide mechanism 100.

[0084] According to the damage site estimation device 30 of the first embodiment, a position on the guide rail 110 at which the extracted estimated damage site does not overlap with the sliding member 130 is calculated as the slider recommended position data. Thus, for example, it is possible to cause the sliding member 130 to move to a position that does not overlap with the estimated damage site based on the calculated slider recommended position data at the end of the motion program. Thereby, at the time of inspection, it is possible to reduce the man-hours of work for moving the sliding member 130 to a position that does not overlap with the estimated damage site.

[0085] According to the damage site estimation device 30 of the first embodiment, the estimated damage site data, the axis position data, and the slider recommended position data extracted or calculated by the estimated damage site extraction section 36 are displayed on the display section 37, and thus an operator can easily and intuitively grasp important inspection sites on the guide rail 110 or the position of the sliding member 130.

[0086] The breakage site estimation device 30 according to the first embodiment is able to perform matching of a change in the position of the center of gravity accompanying a change in the posture of the robot 10 or a change in the load due to the motion mode with a site in the linear motion guide mechanism 100 where breakage is likely to occur, and is thus able to extract a posture or a motion of the robot 10 in which breakage is likely to occur when the motion program is executed. Therefore, when a new motion program is created or a robot system is constructed, it is possible to avoid setting of a posture or a motion in which breakage is likely to occur, and thus to prevent breakage of the linear motion guide mechanism 100.

[0087] (Second Embodiment)

[0088] In the second embodiment, only the structure of the portion different from the first embodiment is illustrated. In addition, in the description and the drawings of the second embodiment, the same reference numerals are assigned to members and the like that are equivalent to those of the first embodiment, and repeated description is omitted.

[0089] Figure 8 is a diagram illustrating the overall structure of the robot system 1A of the second embodiment. Figure 9 is a diagram illustrating the relationship between the load P acting on the slide 120 and the life E of the slide 120.

[0090] In the robot system 1A illustrated in Figure 8 , the structure of the breakage site estimation device 30A is different from that of the first embodiment. Specifically, the breakage site estimation device 30A of the second embodiment is provided with a slide life calculation section 39 in place of the safety factor calculation section 35 of the breakage site estimation device 30 of the first embodiment, and is provided with an estimated breakage site extraction section 36A in place of the estimated breakage site extraction section 36 of the breakage site estimation device 30 of the first embodiment.

[0091] The slide life calculation section (breakage estimation value calculation section) 39 calculates the life (breakage estimation value) of each slide 120 at each time t on the basis of the equivalent load P En calculated by the equivalent load calculation section 34, the basic dynamic rated load (safety estimation element) C inherent to the linear motion guide mechanism 100, and a calculation formula of the life of the slide (safety estimation element).

[0092] The basic dynamic rated load C inherent to the linear motion guide mechanism 100 is a load of a fixed direction and size, which is a load with which 90% of a group of identical linear motion guide mechanisms 100 are able to travel a predetermined distance E D without breakage of the material due to rolling fatigue when each of the linear motion guide mechanisms 100 is individually moved under the same conditions. D50 km in the case where a ball is used as the rolling body 140 (refer to Figure 4 ), and 100 km in the case where a roller is used as the rolling body 140.

[0093] Figure 9 The load-life curve shown indicates the relationship between the load P acting on the slide 120 and the life E. As shown in Figure 9 , the basic dynamic rating load C can be determined from the position of the load-life curve corresponding to the distance E D (50 km, for example). Further, the life E of the slide 120 is expressed in terms of the total distance traveled (km) that 90% of which can be reached without causing flaking when a set of identical linear motion guide mechanisms 100 are individually moved under the same conditions.

[0094] As a calculation formula of the slide life, for example, the following formula (3) or formula (4) can be used.

[0095] E B = (α x C / P En ) 3 x 50... (3)

[0096] E R = (α x C / P En ) 10 / 3 x 50... (4)

[0097] Here, E B of formula (3) is the life of the slide when a ball is used as the rolling body 140. E R of formula (4) is the life of the slide when a roller is used as the rolling body 140. In formulas (3) and (4), α is a coefficient that takes into account the usage conditions of the linear motion guide mechanism 100.

[0098] The estimated damage site extraction section 36A extracts the estimated damage site of the linear motion guide mechanism 100 based on the life E (EB or ER) of the slide at each time t calculated by the slide life calculation section 39, and the position of each slide 120 on the rail 110 at each time t (refer to Figure 3 ). Figure 10 is a diagram that explains the processing of extracting the estimated damage site of the linear motion guide mechanism 100 in the estimated damage site extraction section 36A. Figure 10 is a diagram that shows the processing performed with respect to any one of the four slides 120 (refer to Figure 5 ). Figure 10is a graph showing the relationship between the position of the slider 120 in the z direction of the guide rail 110 (horizontal axis) and the life E of the slider 120. The estimated damage position extraction section 36A extracts the position (position in the z direction on the guide rail 110) of the slider 120 whose life E is smaller than the reference value Es of the life, on the basis of the reference value Es of the life. In Figure 10 In the example shown, the range of z1 to z2 on the guide rail 110 is extracted as the estimated damage position (important inspection position).

[0099] The position of the slider 120 whose life En is smaller than the reference value Es of the life is considered to be a position where the life is short and damage is likely to occur. Therefore, in the estimated damage position extraction section 36A of the second embodiment, it is possible to more accurately extract the estimated damage position of the linear motion guide mechanism 100 provided to the robot 10 or the linear motion guide mechanism 100 that cooperates with the robot 10, by extracting the position of the slider 120 whose life En is smaller than the reference value Es of the life.

[0100] Next, a specific example of the process of extracting the estimated damage position of the linear motion guide mechanism 100 in the damage position estimation device 30A of the second embodiment will be described.

[0101] Figure 11 is a flowchart showing the process procedure of the estimated damage position extraction program executed in the damage position estimation device 30A. Figure 11 The process of the estimated damage position extraction program shown is executed in synchronization with the motion program of the robot 10. Furthermore, Figure 11 The estimated damage position extraction program shown is different from the estimated damage position extraction program of the first embodiment, but in Figure 11 In the flowchart shown, the processes of steps S201 to 204 are substantially the same as the processes of steps S101 to 104 of the flowchart shown in the first embodiment (refer to Figure 7 ) and thus the description thereof will be omitted.

[0102] In Figure 11 In step S205 shown, the slider life calculation section 39 calculates the life E of each slider 120 at each time t on the basis of the equivalent load P En calculated by the equivalent load calculation section 34, the basic dynamic rated load C inherent to the linear motion guide mechanism 100, and a calculation formula of the life of the slider, to calculate the life E of each slider 120 at each time t (slider life calculation process: damage estimation value calculation process).

[0103] In Figure 11 In step S206 shown, the estimated damage position extraction section 36A extracts the position of each slider 120 on the guide rail 110 at each time t on the basis of the life E of each slider 120 at each time t calculated by the slider life calculation section 39, and the position of each slider 120 on the guide rail 110 at each time t (refer to Figure 3), to extract an estimated damage site of the linear motion guide mechanism 100 (estimated damage site extraction step). After the end of step S206, the estimated damage site extraction section 36A causes the storage section 38 to store estimated damage site data related to the extracted estimated damage site and axis position data related to the positions of the respective axes of the robot 10 at the time of extraction of the estimated damage site, and ends the processing of the present flowchart.

[0104] Further, the display section 37 can be caused to display the estimated damage site data, the axis position data, and the slider recommended position data, for example, based on an instruction of an operator, after the end of the processing of step S206.

[0105] (Modified Modes)

[0106] In the embodiment, an example in which the estimated damage site data, the axis position data, and the slider recommended position data extracted or calculated by the estimated damage site extraction section 36 (or 36A) are displayed on the display section 37 is described, but only specific data designated by an operator can be displayed on the display section 37. In addition, the estimated damage site data, the axis position data, and the slider recommended position data can be transmitted to the robot control device 20 and displayed on the display section 23 of the robot control device 20.

[0107] In the embodiment, the position information output section that outputs the estimated damage site data, the axis position data, and the slider recommended position data as position information is not limited to the display section 37 that is a display device, but can be, for example, a printing device, a projector device, a sound output device, or the like.

[0108] In the embodiment, an example in which the damage site estimation device 30 (or 30A) is connected to the robot control device 20 is described, but the damage site estimation device 30 (or 30A) can be connected to a simulation device that is not connected to the robot 10. By being configured like this, in the simulation device, in the case where a change in the position of the center of gravity accompanying a change in the posture of the robot 10 or a change in the load due to the motion pattern is simulated and studied, the estimated damage site data or the axis position data extracted or calculated by the estimated damage site extraction section 36 (or 36A) can be utilized.

[0109] Explanation of Reference Signs

[0110] 1, 1A: robot system; 10: robot; 11: arm; 12: tool; 20: robot control device; 21: control section; 22: operation input section; 23: display section; 24: storage section; 30, 30A: damage estimation device; 31: data acquisition section; 32: moment calculation section; 33: load calculation section; 34: equivalent load calculation section; 35: safety factor calculation section (damage estimation value calculation section); 36, 36A: estimated damage location extraction section; 37: display section (position information output section); 39: slide life calculation section (damage estimation value calculation section); 100: linear motion guide mechanism; 110: guide rail; 120: slide; 130: sliding member.

Claims

1. A damage estimation device for estimating damage points in a linear motion guiding mechanism used in a robot, wherein, The linear motion guiding mechanism includes one or more sliding members configured to move freely in a linear fashion on a guide rail, and a sliding component disposed on the sliding members. The damage estimation device includes: The data acquisition unit acquires physical parameters related to the position, velocity, and acceleration of each axis of the robot, as well as external forces acting on the robot, at each moment when the robot's motion program is executed. The external force and torque calculation unit calculates the external force and torque acting on the reference position of the sliding member at each moment based on the physical parameters related to the position, velocity and acceleration of each axis of the robot, the external force acting on the robot, and the geometric parameters related to the link length and arm weight of the robot, which are obtained by the data acquisition unit. The load calculation unit calculates the load acting on the sliding member at each moment based on the external force and torque acting on the reference position calculated by the external force and torque calculation unit, and the distance from the reference position of the sliding member to the center of gravity position of the sliding member. The equivalent load calculation unit calculates the equivalent load of the sliding member at each time based on the load acting on the sliding member at each time calculated by the load calculation unit and the formula for calculating the equivalent load. The damage estimation calculation unit calculates the damage estimate of the sliding member at each time based on the equivalent load of the sliding member at each time calculated by the equivalent load calculation unit and the safety estimation element. as well as The estimated damage extraction unit extracts the estimated damage location of the linear motion guide mechanism based on the estimated damage value of the slider at each time moment calculated by the damage estimation calculation unit and the position of the slider on the guide rail at each time moment.

2. The damage estimation device according to claim 1, wherein, The damage estimation calculation unit calculates the static safety factor of the sliding component at each moment based on the equivalent load of the sliding component calculated by the equivalent load calculation unit and the formula for calculating the safety factor, which is the safety estimation element, and uses this as the damage estimation value. The estimated damage extraction unit extracts the estimated damage location of the linear motion guide mechanism based on the static safety factor of the slider at each time moment calculated by the damage estimation calculation unit and the position of the slider on the guide rail at each time moment.

3. The damage estimation device according to claim 1, wherein, The damage estimation calculation unit calculates the lifespan of the slider at each moment based on the equivalent load of the slider calculated by the equivalent load calculation unit, the basic dynamic rated load inherent in the linear motion guide mechanism (which is the safety estimation element), and the calculation formula for the slider lifespan (which is the safety estimation element), and uses this lifespan as the damage estimation value. The estimated damage extraction unit extracts the estimated damage points of the linear motion guide mechanism based on the lifespan of the slider at each time moment calculated by the damage estimation calculation unit and the position of the slider on the guide rail at each time moment.

4. The damage estimation device according to any one of claims 1 to 3, wherein, The estimated damage extraction unit calculates the position on the guide rail where the estimated damage does not overlap with the sliding member.

5. The damage estimation device according to claim 4, wherein, It also includes a position information output unit, which outputs at least one of the estimated damage point, the position of each axis of the robot at the estimated damage point, and the position where the estimated damage point does not overlap with the sliding member as position information.

6. The damage estimation device according to any one of claims 1 to 3, wherein, The external force and torque calculation unit calculates the external force and torque around each of the three orthogonal coordinate axes set at the reference position of the sliding member, and uses them as the external force and torque acting on the reference position of the sliding member at each time.

7. The damage estimation device according to any one of claims 1 to 3, wherein, The load calculation unit calculates the load P in the height direction of the slider, which is orthogonal to the long side direction of the guide rail. Rn and the load P in the width direction of the slider. Tn This serves as the load acting on the sliding member.

8. The damage estimation device according to claim 7, wherein, In the equivalent load calculation unit, the formula for calculating the equivalent load of the sliding member at each moment is as follows: Equivalent load P En =Kx·P Rn +Ky·P Tn , Kx and Ky are the inherent equivalent coefficients of the linear motion guiding mechanism.

9. The damage estimation device according to claim 2, wherein, In the damage estimation calculation unit, the formula for calculating the safety factor used to calculate the static safety factor of the sliding member at each time point is: Static safety factor F Sn =C0 / P En , C0 is the inherent basic static rated load of the linear motion guide mechanism.

10. The damage estimation device according to claim 9, wherein, The estimated damage extraction unit extracts the equivalent load P of the sliding member at each moment calculated by the equivalent load calculation unit. En The static safety factor F calculated based on the damage estimate calculation unit is compared to... Sn The calculated time period with a low baseline value is used to extract the position of the slider corresponding to the extracted time period as the estimated damage point of the linear motion guide mechanism.

11. A method for estimating damage points, comprising extracting estimated damage points from a linear motion guiding mechanism of a robot or a linear motion guiding mechanism cooperating with the robot, wherein, The method for estimating the damage point uses a damage point estimation device that estimates the damage point of a linear motion guiding mechanism used in a robot. The linear motion guiding mechanism includes one or more sliding members configured to move freely in a linear fashion on a guide rail, and a sliding component disposed on the sliding members. The method for estimating the damage includes the following steps: The data acquisition process acquires physical parameters related to the position, velocity, and acceleration of each axis of the robot, as well as external forces acting on the robot, at each moment when the robot's motion program is executed. The external force and torque calculation process calculates the external force and torque acting on the reference position of the sliding member at each moment based on the physical parameters related to the position, velocity and acceleration of each axis of the robot, the external force acting on the robot, and the geometric parameters related to the link length and arm weight of the robot obtained through the data acquisition process. The load calculation process calculates the load acting on the sliding member at each moment based on the external force and torque acting on the reference position calculated by the external force and torque calculation process, and the distance from the reference position of the sliding member to the center of gravity position of the sliding member. The equivalent load calculation process calculates the equivalent load of the sliding member at each time moment based on the load acting on the sliding member at each time moment calculated by the load calculation process and the formula for calculating the equivalent load. The damage estimation calculation process calculates the damage estimate of the sliding component at each time moment based on the equivalent load of the sliding component at each time moment calculated through the equivalent load calculation process, and the safety estimation elements. as well as The estimated damage extraction process extracts the estimated damage points of the linear motion guide mechanism based on the estimated damage values ​​of the slider at each time moment calculated by the damage estimation calculation process and the position of the slider on the guide rail at each time moment.

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