Performance comparison system and performance comparison method

Abstract

To realize a performance comparison system which can compare performances concerning robot arm control by use of a vision sensor and robot arm control by use of a force sensor.SOLUTION: A controller (15) performs: a first demonstration process in which an operation predetermined for a work-piece (W) is demonstrated by controlling a robot arm (11) with reference to an output signal of a force sensor (13): a second demonstration process in which an operation predetermined for the work-piece (W) is demonstrated by controlling the robot arm (11) with reference to an output signal of a vision sensor (14).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a performance comparison system and a performance comparison method for comparing the performance of sensors used to control a robotic arm.

Background Art

[0002] Robotic arms are widely used to automate various operations. Although a robotic arm operates as instructed in advance, it may not be able to complete delicate operations by itself. In such a case, the operation of the robotic arm is controlled with reference to the output information from a sensor. As sensors used for controlling a robotic arm, a vision sensor that detects the position of a workpiece and a force sensor that detects the force and / or moment acting on the workpiece are typical.

[0003] Patent Document 1 discloses a robot that operates with reference to the output signal of a vision sensor. Patent Document 2 discloses a robot equipped with a force sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] There is a need to compare the performance of robot arm control using a vision sensor and robot arm control using a force sensor in an easy-to-understand manner. For example, a manufacturer of vision sensors wants to show visitors at an exhibition or the like in an easy-to-understand manner that the control performance of a robot arm using a vision sensor is superior. Conversely, a manufacturer of force sensors wants to show visitors at an exhibition or the like in an easy-to-understand manner that the control performance of a robot arm using a force sensor is superior. However, there has been no system that meets such needs.

[0006] One aspect of the present invention has been made in view of the above problems, and an object thereof is to realize a performance comparison system and a performance comparison method capable of comparing the performance of robot arm control using a vision sensor and robot arm control using a force sensor.

Means for Solving the Problems

[0007] A performance comparison system according to one aspect of the present invention includes a robot arm, a robot hand attached to the robot arm for holding a workpiece, a force sensor for detecting a force and a moment acting on the workpiece, a vision sensor for detecting the position of the workpiece, and a controller for controlling the robot arm. Then, the controller included in the performance comparison system performs a first demonstration step of demonstrating a predetermined operation on the workpiece by controlling the robot arm with reference to the output signal of the force sensor, and a second demonstration step of demonstrating the predetermined operation on the workpiece by controlling the robot arm with reference to the output signal of the vision sensor.

[0008] A performance comparison method according to an aspect of the present invention uses a robot arm, a robot hand attached to the robot arm and holding a workpiece, a force sensor for detecting a force and a moment acting on the workpiece, and a vision sensor for detecting the position of the workpiece. The performance comparison method includes a first demonstration step of demonstrating a predetermined operation on the workpiece by controlling the robot arm with reference to an output signal of the force sensor, and a second demonstration step of demonstrating the predetermined operation on the workpiece by controlling the robot arm with reference to an output signal of the vision sensor.

Effect of the Invention

[0009] According to the present invention, it is possible to compare the performances of controlling a robot arm using a vision sensor and controlling a robot arm using a force sensor.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0011] (Basic Configuration of Performance Comparison System) The basic configuration of a performance comparison system 1 according to an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a perspective view showing the configuration of the performance comparison system 1.

[0012] As shown in FIG. 1, the performance comparison system 1 includes a robot arm 11, a robot hand 12, a force sensor 13, a vision sensor 14, and a controller 15.

[0013] In this embodiment, a vertically articulated robot arm is used as the robot arm 11. Further, a gripping hand for gripping the workpiece W is used as the robot hand 12. Note that the robot hand 12 may hold the workpiece W by a method other than gripping. Examples of the holding method other than gripping include holding by suction, holding by magnetic force, and holding by electrostatic force.

[0014] The force sensor 13 detects the force and moment acting on the workpiece W. The force sensor 13 provides an output signal representing the detected force and moment to the controller 15. The vision sensor 14 detects the position of the workpiece W. The vision sensor 14 provides an output signal representing the detected position to the controller 15.

[0015] In this embodiment, a six-axis force sensor is used as the force sensor 13. The force sensor 13 is interposed between the robot arm 11 and the robot hand 12, and detects the force Fx in the x-axis direction, the force Fy in the y-axis direction, the force Fz in the z-axis direction, the moment Mx around the x-axis, the moment My around the y-axis, and the moment Mz around the z-axis acting on the workpiece W. Here, the z-axis is an axis parallel to the central axis of the final link of the robot arm 11, the x-axis is an axis orthogonal to the z-axis, and the y-axis is an axis orthogonal to the z-axis and the x-axis.

[0016] The controller 15 performs a first demonstration step of demonstrating a predetermined operation by controlling the robot arm 11 based on the output signal of the force sensor 13 (hereinafter also referred to as "force sensor control"), and (2) controlling the robot arm 11 based on the output signal of the vision sensor 14 (hereinafter also referred to as "vision sensor control") to perform a second demonstration step of demonstrating a predetermined operation.

[0017] In addition, in the present embodiment, as a predetermined operation, an operation of fitting a cylindrical workpiece W into a hole H having a circular cross-section provided in another workpiece W' is assumed. However, the operations demonstrated in the first demonstration step and the second demonstration step are not limited to this. For example, a screwing operation of screwing a cylindrical workpiece W having a thread formed on its outer surface into a hole H having a circular cross-section provided in another workpiece W' and having a thread formed on its inner surface may be demonstrated in the first demonstration step and the second demonstration step. Further, a series of operations including the fitting operation and the screwing operation may be demonstrated in the first demonstration step and the second demonstration step.

[0018] As described above, according to the performance comparison system 1, operations by force sensor control and operations by vision sensor control can be demonstrated respectively. Therefore, the performance comparison system 1 can be suitably used, for example, as an exhibit showing the superiority of force sensor control over vision sensor control or the superiority of vision sensor control over force sensor control. For example, when there is uncertainty in the position of the workpiece W', force sensor control is more advantageous than vision sensor control. In this case, the performance comparison system 1 can be suitably used as an exhibit showing the superiority of force sensor control over vision sensor control.

[0019] (Other configurations of the performance comparison system 1) Regarding other configurations of the performance comparison system 1, a description will be continued with reference to FIG. 1.

[0020] The performance comparison system 1 further includes a light source 16. The light source 16 is a light source for irradiating the workpiece W with disturbing light. The controller 15 performs the first demonstration step and the second demonstration step while the light source 16 is lit. Thereby, operations by force sensor control and operations by vision sensor control can be demonstrated respectively in a working environment where disturbing light exists.

[0021] In a working environment where external stray light exists, it may be difficult to identify the position of the work W1 by the vision sensor 14. In this case, it becomes difficult to control the robot arm 11 based on the output signal of the vision sensor 14. As a result, force sensor control becomes more advantageous than vision sensor control. For this reason, the performance comparison system 1 including the light source 16 can be suitably used, for example, as an exhibit showing the superiority of force sensor control over vision sensor control in a working environment where external stray light exists.

[0022] (Other configurations of the performance comparison system 2) Regarding other configurations of the performance comparison system 1, it will be described with continued reference to FIG. 1.

[0023] The performance comparison system 1 further includes a selector 17. The selector 17 is a configuration for allowing the user to select whether to perform the first demonstration process or the second demonstration process. In the present embodiment, as the selector 17, a selector having a "force sensor" button 17a, a "vision sensor" button 17b, and a "start" button 17c is used. The output signal of the selector 17 is a signal indicating the states of these buttons and is provided to the controller 15.

[0024] The controller 15 selects whether to perform the first demonstration process or the second demonstration process based on the output signal of the selector 17. For example, when the "start" button 17c is pressed while the "force sensor" button 17a is pressed, the controller 15 performs the first demonstration process. On the other hand, when the "start" button 17c is pressed while the "vision sensor" button 17b is pressed, the controller 15 performs the second demonstration process. For this reason, when the performance comparison system 1 including the selector 17 is used as an exhibit, visitors can freely select whether to observe a demonstration of work by force sensor control or a demonstration of work by vision sensor control.

[0025] (Other configurations of the performance comparison system 3) The other configurations of the performance comparison system 1 will be described with reference to FIGS. 1 and 2.

[0026] The performance comparison system 1 further includes a display 18. The display 18 is configured to display a graph representing the time change of the force and / or moment acting on the workpiece W during the first demonstration process. The controller 15 creates the above-described graph with reference to the output signal of the force sensor 13 and displays the created graph on the display 18.

[0027] An example of the graph displayed on the display 18 is shown in FIG. 2. The graph shown in FIG. 2 is a graph showing the time change of the force Fz acting on the workpiece W during the first demonstration process. The graph shown in FIG. 2 shows a threshold Th for bite-in determination. When the force Fz acting on the workpiece W exceeds the threshold Th, there is a risk that the workpiece W bites into the workpiece W' and one or both of the workpiece W and the workpiece W' are damaged. In the graph shown in FIG. 2, the force Fz acting on the workpiece W during the first demonstration process does not exceed the threshold Th. Therefore, when the performance comparison system 1 is used as an exhibit, visitors can easily understand that the fitting operation by force sensor control can be performed without causing bite-in.

[0028] Note that the graph displayed on the display 18 is not limited to the graph showing the time change of the force Fz acting on the workpiece W during the first demonstration process. The following graphs, or combinations of the following graphs, may be displayed on the display 18.

[0029] (1) A graph showing the time change of the force Fz acting on the workpiece W during the first demonstration process, (2) A graph showing the time change of the moment Mx acting on the workpiece W during the first demonstration process, (3) A graph showing the time change of the moment My acting on the workpiece W during the first demonstration process.

[0030] (Flow of the performance comparison method) The flow of the performance comparison method S1 implemented using the performance comparison system 1 will be described with reference to FIG. 3. FIG. 3 is a flowchart showing the flow of the performance comparison method S1.

[0031] The performance comparison method S1 is, for example, a performance comparison method implemented when the "Start" button 17c of the selector 17 is pressed, and includes a lighting process S11, a selection process S12, a first demonstration process S13, a second demonstration process S14, and a lighting-off process S15.

[0032] The lighting process S11 is a process in which the controller 15 lights the light source 16. From the start of the lighting process S11 until the lighting-off process S15 is implemented, the light source 16 continues to irradiate the workpiece W with disturbing light.

[0033] The selection process S12 is a process in which the controller 15 selects whether to implement the first demonstration process S13 or the second demonstration process S14 with reference to the output signal of the selector 17. For example, when the "Force sensor" button 17a of the selector 17 is pressed, the controller 15 implements the first demonstration process S13. Also, when the "Vision sensor" button 17b of the selector 17 is pressed, the controller 15 implements the second demonstration process S14.

[0034] The first demonstration process S13 is a process in which the controller 15 controls the robot arm 11 with reference to the output signal of the force sensor 13 to demonstrate a predetermined operation. In the first demonstration process S13, the controller 15 creates a graph representing the time change of the force and / or moment acting on the workpiece W, and displays the created graph on the display 18. The second demonstration process S14 is a process in which the controller 15 controls the robot arm 11 with reference to the output signal of the vision sensor 14 to demonstrate a predetermined operation.

[0035] The lighting-off process S15 is a process in which the controller 15 Eliminate turns off the light source 16. By implementing the lighting-off process S15, the performance comparison method S1 is completed.

[0036] (Supplementary Notes) The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in the above-described embodiments are also included in the technical scope of the present invention.

Description of Reference Numerals

[0037] 1 Performance comparison system 11 Robot arm 12 Robot hand 13 Force sensor 14 Vision sensor 15 Controller 16 Light source 17 Selector 18 Display

Claims

A performance comparison system for comparing the performance of controlling a robot arm using a vision sensor and controlling a robot arm using a force sensor, comprising: the robot arm, a robot hand attached to the robot arm for holding a workpiece, the force sensor for detecting a force and a moment acting on the workpiece, the vision sensor for detecting the position of the workpiece, a controller for controlling the robot arm, and a light source for irradiating the workpiece with disturbing light that makes it difficult to specify the position of the workpiece by the vision sensor; the controller performs a first demonstration step of demonstrating a predetermined operation on the workpiece by controlling the robot arm with reference to an output signal of the force sensor while the light source is lit, and a second demonstration step of demonstrating the predetermined operation on the workpiece by controlling the robot arm with reference to an output signal of the vision sensor while the light source is lit; A performance comparison system characterized by the above.

2. further comprising a selector; the controller selects whether to perform the first demonstration step or the second demonstration step with reference to an output signal of the selector; The performance comparison system according to claim 1, characterized by the above.

3. further comprising a display; the controller creates a graph representing a time change of one or both of the force and the moment acting on the workpiece during the execution of the first demonstration step with reference to an output signal of the force sensor, and displays the created graph on the display; The performance comparison system according to claim 1 or 2, characterized by the above.

4. The predetermined operation is a fitting operation, a screwing operation, or a series of operations including these operations. The performance comparison system according to any one of claims 1 to 3, characterized by the above.

5. A performance comparison method for comparing the performance of controlling a robot arm using a vision sensor and controlling a robot arm using a force sensor, comprising: the robot arm, a robot hand attached to the robot arm, the robot hand holding a workpiece, the force sensor detecting a force and a moment acting on the workpiece, a vision sensor detecting a position of the workpiece, and a light source irradiating the workpiece with disturbing light that makes it difficult to specify the position of the workpiece by the vision sensor; a first demonstration step of demonstrating a predetermined operation on the workpiece by controlling the robot arm with reference to an output signal of the force sensor while the light source is lit; and a second demonstration step of demonstrating the predetermined operation on the workpiece by controlling the robot arm with reference to an output signal of the vision sensor while the light source is lit; A performance comparison method characterized by the above.

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