robot systems

Abstract

This provides a robotic system that can more accurately avoid nearby objects. [Solution] The robot system 10 comprises a robot 1, a plurality of sensors 2a, 2b, and 2c provided on the robot 1 that output sensor values ​​corresponding to the capacitance generated between them and an object, and each has a different object detection direction 5, and a control device 3 that compares the integral values ​​of the sensor values ​​of sensors 2a, 2b, and 2c and performs an avoidance operation of the robot with respect to the object.

Description

Technical Field

[0001] The present invention relates to a robot system including a robot and a control device.

Background Art

[0002] There are cases where a human and a robot cooperate to perform work on a workpiece. A robot used in such a case is called a collaborative robot.

[0003] For example, in Patent Document 1, it is described that in a collaborative robot, upon receiving a designation of an operation section, a plurality of path candidates are generated, and the selected path candidate is determined as an operation path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when selecting an operation path from a plurality of pre-generated paths, it may be difficult for the robot to avoid an object nearby. Also, in a robot such as a collaborative robot, a capacitance sensor may be mounted, and there is room to more accurately avoid an object using such a sensor.

[0006] In view of the above problems, an object of the present invention is to provide a robot system that can more accurately avoid an object nearby.

Means for Solving the Problems

[0007] To solve the above problems, the robot system according to the present invention comprises a robot, a plurality of sensors provided on the robot that output sensor values ​​corresponding to the capacitance generated between the robot and an object, and each sensor has a different object detection direction, and a control device that compares the integral value of the sensor values ​​of each sensor and performs an avoidance operation of the robot with respect to the object.

[0008] Furthermore, in the robot system, the control device identifies the sensor with the smallest integrated value among the plurality of sensors, and determines the robot's avoidance direction based on the detection direction corresponding to the identified sensor.

[0009] Furthermore, in the robot system, when the control device detects an object with at least one of the multiple sensors, it compares the integral values ​​of the sensor values ​​of the multiple sensors to determine the avoidance direction and performs an avoidance maneuver for the robot.

[0010] Furthermore, in a robot system, the integral value of the sensor value is the value obtained by accumulating the changes in the sensor value within a predetermined time.

[0011] Furthermore, in the robot system, each of the multiple sensors has a detection electrode, and each detection electrode is input after the signal generated in the oscillation circuit is modulated by each of the mutually orthogonal signals generated in the orthogonal code generator.

[0012] Furthermore, in the robot system, three or more sensors are provided, each with a different detection direction for objects, and the control device compares the integrated values ​​of the sensor values ​​from the three or more sensors to perform avoidance maneuvers for the robot. [Effects of the Invention]

[0013] According to the robot system of the present invention, nearby objects can be avoided with greater precision. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram showing an example of the overall configuration of a robot system according to an embodiment of the present invention. [Figure 2] This is a diagram showing an example of a configuration related to the input and output of a plurality of sensors in FIG. 1. [Figure 3] This is a diagram showing an example of various functions in the control device of FIG. 1. [Figure 4] This is a diagram showing an example of the sensor values of each sensor in FIG. 1. [Figure 5] This is a flowchart showing an example of processing by the control device of FIG. 1.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. For ease of understanding the description, the same reference numerals are used for the same components in each drawing as much as possible, and duplicate descriptions are omitted as appropriate.

[0016] ===Embodiment=== <Overall Configuration> FIG. 1 is a diagram schematically showing an example of the overall configuration of a robot system 10 according to an embodiment of the present invention.

[0017] The robot system 10 is an industrial robot that performs processes such as machining and conveyance on a workpiece. Further, the robot system 10 is a collaborative robot that works sharing the same space as a person, for example.

[0018] As shown in FIG. 1, the robot system 10 mainly includes a robot 1, a sensor 2, and a control device 3.

[0019] Robot 1 is a multi-joint robot and has multiple arms and multiple joints. Specifically, Robot 1 comprises a base 7, a first arm A1, a second arm A2, a third arm A3, and a fourth arm A4. The number of arms provided is not limited. The base 7 is the base of Robot 1. The base 7 is fixed to, for example, a floor or wall surface and supports the entire Robot 1. The first arm A1 is connected to the base 7 via a pivot axis. The first arm A1 rotates around the pivot axis relative to the base 7 by a motor (not shown). The second arm A2, third arm A3, and fourth arm A4 rotate around their respective pivot axes by motors (not shown), similar to the first arm A1. A tool or the like is provided at the tip of the fourth arm A4. In this way, the arms are connected to other arms, etc., via pivot axes as joints, making them movable. By moving each joint, Robot 1 performs predetermined actions.

[0020] Sensor 2 is a capacitive sensor that detects objects such as people without contact. In this embodiment, "object" is a broad concept that includes people and objects such as workpieces. For example, Sensor 2 detects the proximity of an object. Sensor 2 may also detect the displacement of an object. In this embodiment, the case in which Sensor 2 detects the proximity of an object is given as an example.

[0021] Sensor 2 is composed of sensing electrodes. The sensing electrodes are, for example, flat plate-shaped and have a planar shape such as a rectangular shape. Note that the shape of the sensing electrodes may be designed according to, for example, the outer shape of the arm, and the specific shape is not limited. Sensor 2 generates an electric field in a predetermined direction from the sensing electrodes. Specifically, Sensor 2 generates an electric field with respect to the side opposite to the main body side of the attached robot 1. That is, Sensor 2 generates an electric field around robot 1. Then, the sensing electrodes of Sensor 2 form a capacitance with nearby objects. Note that the capacitance changes according to the distance between the sensing electrodes and the object. Sensor 2 outputs, as a sensor value, an output corresponding to the capacitance formed between the sensing electrodes and the object. Sensor 2 amplifies the voltage corresponding to the capacitance generated in the sensing electrodes by an amplifier or the like and outputs it as a sensor value. Note that the specific circuit configuration and the like in Sensor 2 are not limited. A shield electrode, an active shield electrode, or the like may be provided on the side opposite to the direction in which the electric field is generated (the main body side of robot 1) with respect to the sensing electrodes.

[0022] Thus, each of Sensors 2 outputs a sensor value corresponding to the capacitance (i.e., distance) formed with the object.

[0023] As shown in FIG. 1, a plurality of Sensors 2 are provided for robot 1. Specifically, it is more preferable that three or more Sensors 2 are provided for robot 1. For example, robot 1 is provided with, as Sensor 2, for example, Sensor 2a, Sensor 2b, and Sensor 2c. Sensor 2a, Sensor 2b, and Sensor 2c are provided on the fourth arm A4. Thus, it is preferable that a plurality of Sensors 2 are provided on a plurality of arms constituting robot 1 or the like.

[0024] Note that the installation position and the number of installations of Sensor 2 on robot 1 shown in FIG. 1 are examples, and the installation position and the number of installations of Sensor 2 are not limited to the specific example shown in FIG. 1.

[0025] Furthermore, sensors 2a, 2b, and 2c each have different object detection directions 5. The object detection direction 5 is the direction of the electric field generated for object detection. For example, the detection direction 5 is the direction perpendicular to the surface of the detection electrode. Specifically, the detection direction 5 is the normal direction at the center position of the surface of the detection electrode. In this embodiment, the object detection direction 5 for sensor 2a is detection direction 5a. The object detection direction 5 for sensor 2b is detection direction 5b. The object detection direction 5 for sensor 2c is detection direction 5c. And detection directions 5a, detection direction 5b, and detection direction 5c are all different directions and are not parallel to each other. It is more preferable that their detection directions 5 are perpendicular to each other. In this way, the robot 1 is provided with multiple sensors 2, and each has a different object detection direction 5. Note that the object detection direction 5 is not limited to the normal direction and may be set according to each sensor 2.

[0026] Figure 2 shows an example of a configuration relating to the input and output of multiple sensors 2. As shown in Figure 2, the signal S1 generated by the oscillation circuit 21 is modulated by signals S2a, S2b, and S2c, respectively, generated by the orthogonal code generator 22. Sensors 2a, 2b, and 2c are then input to the modulated signals S3a, S3b, and S3c. Signals S2a, S2b, and S2c are orthogonal to each other. For example, each sensor 2 is configured with a bridge circuit having a detection electrode. Signals S3a, S3b, and S3c are then input to each of the bridge circuits of each sensor 2. As a result, signals S3a, S3b, and S3c are input to the detection electrode of each sensor 2. When the signal S1 from the oscillation circuit 21 is input to the detection electrode, an electric field can be generated at the detection electrode. Furthermore, by modulating signal S1 using signals S2a, S2b, and S2c, which are orthogonal to each other, mutual interference of the electric fields generated by each sensor 2 is suppressed.

[0027] The signals S4a, S4b, and S4c, which are sensor values ​​output from each sensor 2, are demodulated by the signals S5a, S5b, and S5c generated in the demodulator 23, resulting in signals S6a, S6b, and S6c. Each of the signals S4a and S6a, S4b and S6b, and S4c and S6c represents the same information (detection result) as sensor values. Signals S6a, S6b, and S6c are then output to the control device 3.

[0028] The control device 3 is an information processing device that controls the movement of the robot 1. In this embodiment, the control device 3 also performs avoidance maneuvers for the robot 1 to avoid objects. The control device 3 is configured to include, for example, a CPU, memory, communication device, and storage device, and performs various functions by executing a predetermined program.

[0029] <Functional configuration> Figure 3 shows an example of the various functions of the control device 3. The control device 3 comprises an acquisition unit 30, a detection unit 31, an integration unit 32, a comparison unit 33, a determination unit 34, and a control unit 35.

[0030] The acquisition unit 30 acquires sensor values ​​from each sensor 2. Specifically, the acquisition unit 30 acquires signals S6a, S6b, and S6c from sensor 2a, sensor 2b, and sensor 2c, respectively.

[0031] The detection unit 31 detects objects in accordance with each sensor 2. Specifically, the detection unit 31 compares the sensor value of each sensor 2 with a threshold value to determine whether or not an object is in close proximity to the robot 1. For example, the detection unit 31 compares signal S6a with a threshold value to determine whether or not an object is in close proximity to sensor 2a. The detection unit 31 also compares signal S6b with a threshold value to determine whether or not an object is in close proximity to sensor 2b. The detection unit 31 compares signal S6c with a threshold value to determine whether or not an object is in close proximity to sensor 2c. For example, if the sensor value increases in response to the proximity of an object, the detection unit 31 determines that an object is in close proximity when the sensor value becomes equal to or above the threshold value. Note that the method for determining object proximity using the sensor values ​​of each sensor 2 is not limited to the above. For example, if the sensor value decreases in response to the proximity of an object, the detection unit 31 may determine that an object is in close proximity when the sensor value becomes equal to or below the threshold value.

[0032] Figure 4 shows an example of the sensor values ​​for each sensor 2. Figure 4 shows an example of signals S6a, S6b, and S6c as sensor values. Figure 4 shows a case where the sensor value increases in response to the proximity of an object. For example, when an object approaches sensor 2a, signal S6a becomes above the threshold at time T1. Therefore, the detection unit 31 determines that an object is close to sensor 2a at time T1. Note that at time T1, signals S6b and S6c are below the threshold.

[0033] As shown in Figures 3 and 4, the integration unit 32 calculates the integral value 37 of the sensor value of each sensor 2. Specifically, the integration unit 32 calculates the integral value 37a of the signal S6a of sensor 2a. The integration unit 32 also calculates the integral value 37b of the signal S6b of sensor 2b. The integration unit 32 also calculates the integral value 37c of the signal S6c of sensor 2c. The integral value 37 of the sensor value is the sum of the changes in the sensor value within a predetermined time (unit time). For example, the integral value 37 is the integral value of the sensor value of each sensor 2 within a predetermined time that includes the timing at which the detection unit 31 determines that an object is in close proximity to at least one sensor 2. Specifically, the integral value 37 is the integral value of the sensor value of each sensor 2 from the timing at which the detection unit 31 determines that an object is in close proximity to at least one sensor 2 until the predetermined time before that. Note that the integral value 37 of each sensor value corresponds to the same predetermined time.

[0034] For example, as shown in Figure 4, the integral values ​​37a of signal S6a, 37b of signal S6b, and 37c of signal S6c are calculated in accordance with the time changes of each sensor value between time T1 and time T2, which is a predetermined time earlier.

[0035] Returning to Figure 3, the integration unit 32 calculates an integral value 37 that includes the effect of time changes and outputs it to the comparison unit 33.

[0036] The comparison unit 33 compares the integral values ​​37 of the sensor values ​​of each sensor 2. Specifically, the comparison unit 33 compares the integral values ​​37 of the sensor values ​​of sensor 2a, sensor 2b, and sensor 2c. Then, the comparison unit 33 identifies the sensor 2 among the multiple sensors 2 that has the smallest integral value 37 of its sensor value.

[0037] In the example shown in Figure 4, the comparison unit 33 compares the integral values ​​37a, 37b, and 37c. The comparison unit 33 then identifies that the integral value 37c is smaller than the integral values ​​37a and 37b, and identifies sensor 2c as the sensor 2 with the smallest integral value 37 of the sensor value.

[0038] Returning to Figure 3, the comparison unit 33 outputs the information of the sensor 2 with the smallest identified integral value 37 to the determination unit 34.

[0039] The determination unit 34 determines the avoidance direction of the robot 1 based on the sensor 2 with the smallest integral value 37. Specifically, the determination unit 34 determines the avoidance direction based on the detection direction 5 of the sensor 2 with the smallest integral value 37. In this embodiment, the determination unit 34 determines the detection direction 5 of the identified sensor 2 as the avoidance direction of the robot 1.

[0040] In the example shown in Figure 4, the determination unit 34, upon detection of an object by sensor 2a at time T1, determines the detection direction 5c of sensor 2c, which has the smallest integral value 37, as the avoidance direction for robot 1. Here, for example, according to signal S6b in Figure 4, the sensor value increased at time T3, which is before time T1, so it is assumed that the object was close to sensor 2b at time T3. Therefore, the integral value 37b is greater than the integral value 37c, and is not the smallest integral value 37. By using the integral value 37 in this way, it is possible to set the avoidance direction to move away from the object more effectively by also considering the position of the object (proximity state) within a predetermined time in the past.

[0041] Returning to Figure 3, the control unit 35 controls the movement of the robot 1. Specifically, the control unit 35 controls the movement of each arm of the robot 1 to cause the robot 1 to perform a predetermined action. For example, the control controls the rotation of each pivot axis that constitutes each joint of the robot 1.

[0042] Furthermore, the control unit 35 performs an avoidance maneuver for the robot 1 to avoid an object. Specifically, when the control unit 35 detects an object in at least one of the multiple sensors 2 by the detection unit 31 while the robot 1 is performing a predetermined operation, it moves the robot 1 in the avoidance direction determined by the determination unit 34. Since the avoidance direction is determined by the detection direction 5 of the sensor 2 with the smallest integrated value 37 of the sensor values, the detected object can be avoided by moving the robot 1 in the avoidance direction.

[0043] For example, in this embodiment, when the detection direction 5c of sensor 2c is determined to be the avoidance direction of robot 1, an avoidance operation is performed so that the fourth arm A4, which is equipped with sensors 2a, 2b, and 2c, moves in that avoidance direction.

[0044] The control unit 35 performs an avoidance maneuver while the robot 1 is performing a predetermined action. To this end, the control unit 35 controls the robot 1's movement so that the predetermined action it was originally performing continues while moving the robot 1 in the avoidance direction. In other words, a part of the robot 1's predetermined action is changed to an avoidance maneuver, and the robot 1 continues to perform the predetermined action. As a result, the robot 1 continues to perform the predetermined action while avoiding the object.

[0045] <Processing flow> Figure 5 is a flowchart showing an example of the avoidance process flow according to this embodiment. Each of the following steps is repeatedly executed at a predetermined control cycle during the operation of the robot 1. The order and content of each of the following steps can be changed as appropriate.

[0046] (Step SP10) The acquisition unit 30 acquires sensor values ​​from each sensor 2. Then, the process moves to step SP11.

[0047] (Step SP11) The detection unit 31 compares the sensor values ​​of each sensor 2 with a threshold value to determine whether or not an object is in close proximity to the robot 1. If an object is in close proximity to the robot 1, the process proceeds to step SP12. If an object is not in close proximity to the robot 1, the process ends.

[0048] (Step SP12) The integration unit 32 calculates the integral value 37 of the sensor value for each sensor 2. Then, the process moves on to step SP13.

[0049] (Step SP13) The comparison unit 33 identifies the sensor 2 among the multiple sensors 2 that has the smallest integrated value 37 of the sensor values. Then, the process proceeds to step SP14.

[0050] (Step SP14) The determination unit 34 determines the avoidance direction based on the detection direction 5 of sensor 2 with the smallest integral value 37. Then, the process proceeds to step SP14.

[0051] (Step SP15) The control unit 35 moves the robot 1 in the determined avoidance direction. Then the process ends.

[0052] In this way, an avoidance maneuver corresponding to an approaching object is performed on robot 1 while it is performing a predetermined action.

[0053] <Effects and Effects> In this embodiment, multiple sensors 2 with different detection directions 5 are provided, and the robot 1 performs avoidance maneuvers by comparing the integral values ​​37 of the sensor values ​​from each sensor 2. Therefore, avoidance maneuvers can be performed considering the state of each sensor 2, making it possible to avoid nearby objects with greater accuracy. Furthermore, by comparing the integral values ​​37 of the sensor values ​​from each sensor 2, it becomes possible to perform avoidance maneuvers considering the time change of the sensor values, thereby improving the accuracy of avoidance maneuvers for objects. In addition, compared to stopping the operation in the event of an object, the robot 1 can continue the operation it was originally performing due to the avoidance maneuver, suppressing a decrease in work efficiency.

[0054] Furthermore, since the avoidance direction is determined by the detection direction 5 of sensor 2, which has the smallest integrated value 37 of the sensor values, it becomes possible to efficiently avoid objects.

[0055] Furthermore, when an object is detected by multiple sensors 2, the system determines the direction of avoidance and performs an avoidance maneuver. This makes it possible to perform an avoidance maneuver when there is a possibility that an object is nearby.

[0056] Furthermore, by making the integrated value 37 of the sensor value the sum of the changes in the sensor value within a predetermined time, it becomes possible to perform avoidance actions while taking into account the state of changes in the sensor value within a predetermined time.

[0057] Furthermore, the signal S1 of the oscillation circuit 21 is modulated by the mutually orthogonal signals S2a, S2b, and S2c, respectively, and input to the detection electrodes, thereby suppressing interference between the electric fields generated by each detection electrode.

[0058] Furthermore, by using three or more sensors 2 to perform avoidance maneuvers, it becomes possible to set the avoidance direction from three or more detection directions 5, thus enabling more effective avoidance maneuvers.

[0059] ===Literal translation=== This disclosure is not limited to the embodiments described above. In other words, any design modifications made to the above-described examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. Furthermore, the elements of the above embodiments and the following modifications can be combined to the extent that it is technically possible, and any combination thereof is also included within the scope of this disclosure, as long as it retains the features of this disclosure.

[0060] Furthermore, in the above embodiment, one example was given of a case where multiple sensors 2, each with a different object detection direction 5, are provided on the same arm. However, the arrangement of the multiple sensors 2 is not limited to the above. That is, multiple sensors 2 provided on the robot 1, not limited to the same arm, may be facing different detection directions 5, and object avoidance control may be performed using these multiple sensors 2.

[0061] Furthermore, although the above embodiment described an example in which three or more sensors 2 are provided to the robot 1, the number of sensors 2 may be two or more. In fact, it is more preferable to have three or more sensors 2, as this makes it possible to perform avoidance control more effectively. Specifically, the comparison unit 33 compares the integral values ​​37 of the sensor values ​​of three or more sensors 2.

[0062] Furthermore, in the above embodiment, one example was given where the signal S1 from the oscillation circuit 21 input to each sensor 2 is modulated by signals S2a, S2b, and S2c, which are orthogonal to each other. However, modulation may be omitted. For example, if each sensor 2 is sufficiently far apart, the electric fields generated by each sensor 2 are less likely to interfere with each other due to the distance. For this reason, in such cases, the orthogonal code generator 22 may be omitted, and modulation by signals S2a, S2b, and S2c may not be performed. Note that if the orthogonal code generator 22 is omitted, the demodulator 23 is also omitted. If both the orthogonal code generator 22 and the demodulator 23 are omitted, the acquisition unit 30 acquires signals S4a, S4b, and S4c.

[0063] Furthermore, in the above embodiment, the acquisition unit 30 acquires signals S6a, S6b, and S6c, but the signals to be acquired are not limited to those above. For example, the control device 3 may have a demodulation function, and the acquisition unit 30 may acquire and demodulate signals S4a, S4b, and S4c.

[0064] Furthermore, although the above embodiment described a case where the detection direction 5 of the sensor 2 identified as having the smallest integral value 37 is set as the avoidance direction, the embodiment is not limited to this. For example, the avoidance direction may be determined by correcting the detection direction 5 of the identified sensor 2. For example, the detection direction 5 of the sensor 2 with the smallest integral value 37 may be corrected to move away from the detection direction 5 of the sensor 2 in which the object was detected, and this corrected direction may be set as the avoidance direction.

[0065] Furthermore, in the above embodiment, a case was described in which, when an object is detected by the sensor 2 by the detection unit 31 while the robot 1 is performing a predetermined operation, the robot 1 is moved in the avoidance direction. The control unit 35 may also perform stop control of the robot 1. For example, the control unit 35 may compare the sensor value of the sensor 2 with a threshold and stop the operation of the robot 1. For example, if the sensor value increases in response to the proximity of an object, the control unit 35 stops the operation of the robot 1 when the sensor value becomes greater than or equal to the threshold. In this case, it is preferable for the control unit 35 to stop the operation of the robot 1 when it determines that the object is closer than the proximity state detected by the detection unit 31. For example, the threshold for stopping the operation of the robot 1 (e.g., the second threshold) is greater than the threshold used in the detection unit 31 (e.g., the first threshold). The control unit 35 also stops the operation of the robot 1 when the sensor value decreases in response to the proximity of an object and becomes less than or equal to the threshold. In this case, the threshold for stopping the operation of the robot 1 (e.g., the third threshold) is smaller than the threshold used in the detection unit 31 (e.g., the first threshold). Furthermore, the control unit 35 is not limited to stopping the movement of the robot 1, but may also be used to slow down the movement of the robot 1.

[0066] Furthermore, although the above embodiment described an example in which the control device 3 has an integration unit 32, the invention is not limited to this. An integrator for integrating sensor values ​​may be provided separately from the control device 3, and the integrated value of the sensor values ​​may be acquired by the acquisition unit 30. For example, the integrator may be composed of an integration circuit. [Explanation of Symbols]

[0067] 1: Robot 2, 2a~2c: Sensors 3: Control device 5, 5a~5c: Detection direction 10: Robot System 21: Oscillator Circuit 22: Orthogonal code generator 37, 37a~37c: Integral values S1, S2a~S2c: Signals

Claims

1. Robots and, The robot is provided with a plurality of sensors that output a sensor value corresponding to the capacitance generated between it and an object, and each sensor has a different object detection direction. A control device that compares the integrated values ​​of the sensor values ​​from each of the aforementioned sensors and performs an avoidance maneuver for the robot toward an object, A robot system characterized by having the following features.

2. The robot system according to claim 1, characterized in that the control device identifies the sensor with the smallest integrated value of the sensor values ​​among a plurality of sensors, and determines the avoidance direction of the robot based on the detection direction corresponding to the identified sensor.

3. The robot system according to claim 2, characterized in that when the control device detects an object in at least one of the plurality of sensors, it compares the integral values ​​of the sensor values ​​of the plurality of sensors to determine the avoidance direction and performs an avoidance operation of the robot.

4. The robot system according to any one of claims 1 to 3, characterized in that the integral value of the sensor value is the value obtained by accumulating the changes in the sensor value within a predetermined time.

5. Each of the multiple sensors has a detection electrode, The robot system according to any one of claims 1 to 3, characterized in that each of the detection electrodes is input after the signal generated in the oscillation circuit is modulated by each of the mutually orthogonal signals generated in the orthogonal code generator.

6. The aforementioned sensors are provided in groups of three or more, and each sensor has a different detection direction for the object. The robot system according to any one of claims 1 to 3, characterized in that the control device compares the integral values ​​of the sensor values ​​of three or more sensors and performs an avoidance operation of the robot.

Images