Control system, control method, and storage medium

Abstract

A service robot includes a reversely drivable robot arm, a robot body supporting the robot arm, a moving bracket provided at a lower portion of the robot body, and a control unit controlling the robot arm and the moving bracket. The control unit is configured to perform collision mitigation control in response to an action of an external force on the robot arm caused by contact with a surrounding object during movement of the service robot using the moving bracket.

Description

Background of the Invention 1. Technical Field

[0001] The present disclosure relates to a control system, a control method, and a storage medium.

[0002] 2. Description of Related Technology

[0003] Japanese Unexamined Patent Application Publication No. 2022-032166 (JP 2022-032166 A) discloses an autonomous mobile object. In this autonomous mobile object, contact sensors are provided on a plurality of bumpers arranged around the periphery of a moving carriage. The autonomous mobile object is configured to detect contact with surrounding objects based on signals output from the contact sensors. Summary of the Invention

[0004] In the configuration of JP 2022-032166 A, it is necessary to keep the moving speed of the autonomous moving object low so as not to cause damage to the surrounding objects when the bumper collides with the surrounding objects.

[0005] The present disclosure provides a technology for achieving high-speed motion of an autonomous moving object.

[0006] A first aspect of the present disclosure provides a control system comprising: an autonomous mobile object including a back-drivable robotic arm, a robot body supporting the robotic arm, and a moving bracket disposed at a lower portion of the robot body; and a control unit configured to perform collision mitigation control in response to an external force acting on the robotic arm during movement of the autonomous mobile object using the moving bracket, the external force being caused by contact with surrounding objects. With this configuration, high-speed movement of the autonomous mobile object is achieved.

[0007] Collision mitigation control may be control for changing the direction of movement of an autonomous moving object.

[0008] The collision mitigation control may be a control for reducing the movement speed of an autonomous moving object.

[0009] The control unit can be configured to control the robot arm or the moving carriage so that the robot arm is positioned in front of the robot body in the direction of movement of the autonomous moving object during movement of the autonomous moving object using the moving carriage. With the above configuration, contact between the autonomous moving object and surrounding objects can be effectively detected.

[0010] The control unit may be configured to control the robot arm so that the robot arm projects from the front of the moving bracket in the moving direction of the autonomous moving object in a plan view.With the above configuration, contact between the autonomous moving object and surrounding objects can be effectively detected.

[0011] The control unit can be configured to have multiple sensing modes including at least a first sensing mode and a second sensing mode, wherein one of the multiple sensing modes is selected, and the control unit controls the posture of the robot arm based on the selected sensing mode, wherein the first sensing mode is a sensing mode in which the posture of the robot arm is a first posture, and the second sensing mode is a sensing mode in which the posture of the robot arm is a second posture different from the first posture. With the above configuration, different sensing ranges can be achieved.

[0012] The autonomous mobile object may further include a surrounding environment monitoring unit configured to monitor the surrounding environment, and the control unit may be configured to select one of the plurality of sensing modes based on the surrounding environment. With the above configuration, an optimal sensing mode may be selected according to the surrounding environment.

[0013] In the first posture, the height position of the end effector of the robot arm may be a first height position, and in the second posture, the height position of the end effector of the robot arm may be a second height position different from the first height position. With the above configuration, sensing can be performed in a range different from the vertical direction.

[0014] The control unit may be configured to swing the robot arm in a fan-shaped manner during movement of the autonomous mobile object using the moving bracket.With the above configuration, wide-range sensing is achieved.

[0015] The robot arm may include at least two links and a joint connecting the at least two links. The autonomous mobile object may also include: an actuator configured to drive the joint, the actuator being disposed in the robot body; and a dynamic power transmission mechanism configured to transmit dynamic power generated by the actuator to the joint.

[0016] The dynamic power transmission mechanism may include a belt or a wire. With the above configuration, the robot arm is made lightweight.

[0017] The control unit may be configured to perform impedance control of the robot arm.With the above configuration, a back-drivable robot arm may be realized through simple control.

[0018] The control system may further include a contact sensor configured to detect that a surrounding object has come into contact with the moving bracket while the autonomous moving object is being moved using the moving bracket. The control unit may be configured to stop the movement of the autonomous moving object when the contact sensor detects that a surrounding object has come into contact with the moving bracket. With the above configuration, the movement of the autonomous moving object can be stopped when the moving bracket has come into contact with a surrounding object.

[0019] A second aspect of the present disclosure provides a control method for an autonomous mobile object, the autonomous mobile object comprising a back-drivable robotic arm, a robot body supporting the robotic arm, and a movable bracket disposed at a lower portion of the robot body. The control method includes: moving the autonomous mobile object using the movable bracket; and performing collision mitigation control in response to an external force acting on the robotic arm during movement of the autonomous mobile object using the movable bracket, the external force being caused by contact with surrounding objects. This method enables high-speed movement of the autonomous mobile object.

[0020] A non-transitory storage medium storing instructions is provided. The instructions can be executed by one or more processors of a computer and cause the one or more processors to perform the above control method.

[0021] By utilizing the present disclosure, high-speed motion of autonomous moving objects is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Features, advantages, technical significance, and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements, and in which:

[0023] Figure 1 It is a three-dimensional diagram of a service robot;

[0024] Figure 2 is a side view of the robot arm;

[0025] Figure 3 is a side view of the robot arm;

[0026] Figure 4 This is the functional block diagram of the service robot;

[0027] Figure 5 is an explanatory diagram for a first sensing mode;

[0028] Figure 6 is an explanatory diagram for the second sensing mode;

[0029] Figure 7 is an explanatory diagram for the third sensing mode;

[0030] Figure 8 is an explanatory diagram for a fourth sensing mode;

[0031] Figure 9 It is the control process for service robots;

[0032] Figure 10 is a plan view of a service robot in a first modification;

[0033] Figure 11is a control flow for the service robot in the second modification;

[0034] Figure 12 is a schematic diagram of a control system in the third modification;

[0035] Figure 13A It is an illustration of the reverse driving capability;

[0036] Figure 13B is an illustration of reverse drive capability; and

[0037] Figure 13C This is a diagram for explaining reverse driving capability. DETAILED DESCRIPTION

[0038] The following will refer to Figures 1 to 9 to describe the embodiments of the present disclosure.

[0039] Figure 1 An autonomous mobile service robot 1 is shown. Service robot 1 is a specific example of an autonomous mobile object. For example, service robot 1 provides various services in medical facilities, nursing facilities, or other facilities. These services include a delivery service for transporting items, a patrol service for patrolling the facility, and other services. Figure 1 A state in which the service robot 1 carries a beverage container 2 is shown.

[0040] The service robot 1 includes a robot arm 3 , a robot body 4 , a moving bracket 5 provided at a lower portion of the robot body 4 , and a control unit 6 that controls the robot arm 3 and the moving bracket 5 .

[0041] In the embodiment, the robot arm 3 is a multi-joint type. Furthermore, the robot arm 3 is a so-called back-drivable robot arm. When the robot arm 3 is back-drivable, the joint angles of the robot arm 3 typically change when an external force is applied to the robot arm 3. This external force does not include an external force due to gravitational acceleration, but rather refers to an external force generated by contact with surrounding objects.

[0042] The definition of backdrive capability is described in more detail in the Journal of the Robotics Society of Japan, Vol. 31, No. 6, 2013, pp. 548-551 (https: / / www.jstage.jst.go.jp / article / jrsj / 31 / 6 / 31_3L_548 / _pdf / -char / ja).

[0043] The phenomenon in which a robot's joints or actuator output shafts drive the system when an external force is applied to them is called backdrive. Backdrive capability is a concept that indicates "ease of backdrive." When tension is released (muscles relax), a human arm appears to be suspended in mid-air. This high backdrive capability can be easily achieved by living organisms, but it is currently quite difficult for robots to achieve.

[0044] Typically, assumptions include Figure 13A The drive system of an electromagnetic motor and a speed reducer is shown, and backdrive is "a phenomenon in which the speed reducer and motor rotate when an external torque T is applied to the output shaft." In this case, one of the most important factors determining backdrive capability is friction in the speed reducer, and therefore this definition is appropriate when discussing low-friction drive systems from a kinematic perspective. Meanwhile, in robotics, the concept of backdrive capability is often used to discuss robot characteristics. In this context, it is helpful to simply interpret backdrive broadly as "the operation of the output link due to an external force."

[0045] When the reverse drive is interpreted broadly, as a configuration of a drive system that realizes the reverse drive, there can be various configurations. Figure 13B An example is shown in which an external force is detected by a torque sensor and a motor is driven based on a detection signal of the torque sensor. Thus, reverse driving can be achieved even in a drive system including a speed reducer with high friction. In addition, when using Figure 13B When the information of the encoder shown by the dotted line is obtained, various resistances depending on the rotation angle, speed, and acceleration can be realized. From a broader perspective, there is also a method in which a clutch and a brake are used for the output shaft, such as Figure 13C When the clutch is closed, the driven member is suspended, and when the brake is applied, no backdrive is performed. When a viscous damper or elastic body is used instead of a clutch, viscous resistance and compliance can be achieved. Figure 13B The backdrive shown may be referred to as a servo backdrive, and Figure 13C The backdrive shown may be referred to as a mechanical backdrive.

[0046] In short, "reversible" in a broad sense means that the joint angles of the robot arm 3 change when an external force is applied to the robot arm 3. In the narrow sense of "reversible", the action of the external force on the robot arm 3 is detected in some manner, for example, using a torque sensor or an encoder. The narrow sense of "reversible" is configured so that the robot arm 3 is actively controlled based on the detection result, and thus the joint angles of the robot arm 3 are changed in response to the action of the external force on the robot arm 3. In the narrow sense of "reversible", for example, the external force entering the output shaft of the robot arm 3 can be actively processed as a control command signal for the robot, and thereby compensated for friction in the drive system of the robot arm 3.

[0047] Furthermore, regardless of the type of servo motor and reducer included in the robot arm 3, when an infinite external force acts on the robot arm 3, the output shaft of the servo motor rotates more than slightly. Therefore, "reversible" in the embodiments can also be defined by the degree of external force that can change the joint angles of the robot arm 3. That is, in a case where the joint angles of the robot arm 3 change due to contact between the robot arm 3 and a moving object such as a walker or another moving robot, the robot arm 3 can be said to be reversible. Furthermore, in a case where the joint angles of the robot arm 3 change due to contact between the robot arm 3 and a stationary object such as a wall or furniture, the robot arm 3 can be said to be reversible.

[0048] As described above, various techniques can be adopted as a technique for realizing the back-driving capability of the robot arm 3 .

[0049] The first technique is to reduce the reduction ratio of the reduction mechanism provided for the output shaft of the actuator of the robot arm 3. This is because the most important factor hindering the reverse driving capability of the robot arm 3 is the friction in the reduction mechanism, and therefore, the reduction of friction is effective for the reverse driving capability.

[0050] The second technique is to use an electromagnetic clutch for the output shaft of the actuator of the robot arm 3. When the electromagnetic clutch is disengaged, the link driven by the actuator can be temporarily left in a suspended state.

[0051] The third technique is to perform impedance control on the robot arm 3. Impedance control controls the robot arm 3 so that its joints behave like springs or dampers. Impedance control includes impedance control using a torque sensor that directly detects external force and impedance control without a torque sensor.

[0052] In the embodiment, as an example, the reverse driving capability of the robot arm 3 is realized by adopting the third technology. However, the first technology or the second technology may be adopted instead of the third technology.

[0053] The robot body 4 supports the robot arm 3 in a cantilevered manner. The robot body 4 includes a robot base 10, a sliding mechanism 11, an arm base 12, a lifting actuator 13, and a head 14. The robot base 10 has a vertically elongated rectangular parallelepiped shape. The sliding mechanism 11 is provided on the front surface 10a of the robot base 10. The arm base 12 is supported by the sliding mechanism 11 so as to be movable up and down, and is coupled to the robot arm 3. The lifting actuator 13 drives the arm base 12 so that it moves up and down along the sliding mechanism 11. For example, the lifting actuator 13 moves the arm base 12 upward along the sliding mechanism 11, thereby moving the entire robot arm 3 upward. Similarly, for example, the lifting actuator 13 moves the arm base 12 downward along the sliding mechanism 11, thereby moving the entire robot arm 3 downward. The lifting actuator 13 is typically a servo motor. The dynamic power of the lifting actuator 13 is transmitted to the arm base 12 via an endless belt (not shown). The head 14 is disposed above the robot base 10. A camera 15 and a light detection and ranging device (lidar) 16 are provided on the head 14. The camera 15 and the lidar 16 are used to acquire information about the surrounding environment. The camera 15 is a specific example of an image sensor. The camera 15 outputs image data obtained by capturing the surrounding environment to the control unit 6. The lidar 16 is a specific example of a distance sensor. The lidar 16 outputs three-dimensional point cloud data obtained by scanning the surrounding environment to the control unit 6. Instead of the lidar 16, a stereo camera or a pattern projection camera may be used as the distance sensor.

[0054] The moving bracket 5 includes a bracket body 20 and a buffer 21 .

[0055] As an example, the carriage body 20 includes two drive wheels 22, a driven wheel 23, and two carriage motors 24 that respectively drive the two drive wheels 22. The two carriage motors 24 drive the two drive wheels 22 in the same rotation direction and at the same rotation speed, respectively, and thereby the service robot 1 moves forward or backward. The two carriage motors 24 drive the two drive wheels 22 in the same rotation direction and at different rotation speeds, respectively, and thereby the service robot 1 rotates. The two carriage motors 24 drive the two drive wheels 22 in different rotation directions, respectively, and thereby the service robot 1 performs self-rotation. The buffer 21 is a rigid body that is circularly arranged on the outer periphery of the carriage body 20, and the buffer 21 protects the carriage body 20 from colliding with surrounding objects. A buffer sensor 25 is provided in the buffer 21 to detect contact between the buffer 21 and surrounding objects. The buffer sensor 25 is a specific example of a contact sensor. Typically, the buffer sensor 25 is constructed by an acceleration sensor or a strain gauge. However, the configuration of the buffer sensor 25 is not limited to this.

[0056] Figure 2 A side view of the robot arm 3 is shown. The robot arm 3 in the embodiment has a structure that simulates a human arm. That is, the robot arm 3 includes an upper arm link 30, a forearm link 31, a shoulder joint 32, an elbow joint 33, and a wrist joint 34. The upper arm link 30 is connected to the arm base 12 via the shoulder joint 32, so that it can perform pitch and roll rotations. The forearm link 31 is connected to the upper arm link 30 via the elbow joint 33, so that it can perform pitch rotations. A gripping end effector 35 is provided at the distal end of the forearm link 31. The end effector 35 is connected to the forearm link 31 via the wrist joint 34, so that it can perform pitch rotations.

[0057] The arm base 12 of the service robot 1 includes a shoulder joint actuator 40 that drives the shoulder joint 32, an elbow joint actuator 41 that drives the elbow joint 33, and a wrist joint actuator 42 that drives the wrist joint 34. That is, the shoulder joint actuator 40, the elbow joint actuator 41, and the wrist joint actuator 42 are arranged in the arm base 12 of the service robot 1. Thereby, compared with, for example, a direct drive method in which the elbow joint actuator 41 is arranged on the elbow joint 33, the lightweight of the robot arm 3 is achieved. Due to the lightweight of the robot arm 3, the damage caused to the surrounding objects when the robot arm 3 contacts the surrounding objects can be reduced. In other words, by lightweighting the robot arm 3, the reverse driving capability of the robot arm 3 can be achieved at a high level.

[0058] Typically, each of the shoulder joint actuator 40, the elbow joint actuator 41, and the wrist joint actuator 42 is a servo motor. The output shaft of the shoulder joint actuator 40 is connected to the shoulder joint pulley 40b via a reduction mechanism 40a. Similarly, the output shaft of the elbow joint actuator 41 is connected to the elbow joint pulley 41b via a reduction mechanism 41a. Similarly, the output shaft of the wrist joint actuator 42 is connected to the wrist joint pulley 42b via a reduction mechanism 42a.

[0059] The shoulder joint pulley 40b is connected to the upper arm link pulley 30a via an endless belt 30b. The upper arm link pulley 30a is provided in the shoulder joint 32, which serves as the pitch rotation axis of the upper arm link 30. The upper arm link pulley 30a is fixed so as not to rotate relative to the upper arm link 30. Therefore, the endless belt 30b transmits the dynamic power generated by the shoulder joint actuator 40 to the shoulder joint 32. The endless belt 30b is a specific example of a dynamic power transmission mechanism. An equivalent configuration is also provided for the roll rotation of the upper arm link 30.

[0060] The elbow joint pulley 41b is coupled to the forearm link pulley 31a via an endless belt 31b. The forearm link pulley 31a is provided in the elbow joint 33, which serves as the pitch rotation axis of the forearm link 31. The forearm link pulley 31a is fixed so as not to rotate relative to the forearm link 31. Therefore, the endless belt 31b transmits the dynamic power generated by the elbow joint actuator 41 to the elbow joint 33. The endless belt 31b is a specific example of a dynamic power transmission mechanism.

[0061] Wrist pulley 42b is coupled to end effector pulley 35a via two wires 35b. End effector pulley 35a is provided in wrist joint 34, which serves as the pitch rotation axis of end effector 35. One end of each wire 35b is fixed to the outer circumference of wrist pulley 42b, and the other end is fixed to the outer circumference of end effector pulley 35a. Thus, the two wires 35b transmit the dynamic power generated by wrist actuator 42 to wrist joint 34. The two wires 35b are a specific example of a dynamic power transmission mechanism.

[0062] The configuration of the dynamic power transmission mechanism is not limited to the above configuration, and may be, for example, Figure 3 The configuration shown. Figure 3 In the illustrated configuration, a pinion 45 is provided on the output shaft of the elbow joint actuator 41 via a speed reduction mechanism 41a. A pinion 46 fixed so as not to rotate relative to the forearm link 31 is provided in the elbow joint 33. The pinion 45 and the pinion 46 are coupled via a drive shaft 47. That is, a worm gear 48 engaging with the pinion 45 is provided at one end of the drive shaft 47, and a worm gear 49 engaging with the pinion 46 is provided at the other end. A universal joint 50 is provided on the drive shaft 47 so that the drive shaft 47 can be bent at the shoulder joint 32.

[0063] Next, we will refer to Figure 4 The electrical configuration of the service robot 1 is described.

[0064] The control unit 6 includes a central processing unit (CPU) 60, a random access memory (RAM) 61, a read-only memory (ROM) 62, a hard disk drive (HDD) 63, and a communication interface 64. The HDD 63 stores map data 65 related to the service environment. The CPU 60 reads and executes a control program stored in the HDD 63, and as a result, the control program causes the hardware such as the CPU 60 to function as a destination setting unit 70, a self-position estimation unit 71, a route generation unit 72, and an autonomous motion control unit 73.

[0065] The destination setting unit 70 sets a destination of the service robot 1 based on external input through the communication interface 64 .

[0066] The self-position estimating unit 71 estimates the current position of the service robot 1 by collating the image data output from the camera 15 and the map data 65. As the self-position estimating technique, a particle filter is generally used, but the self-position estimating technique is not limited thereto.

[0067] The route generating unit 72 generates a route from the current position of the service robot 1 to a destination.

[0068] The autonomous motion control unit 73 controls the robot arm 3 and the mobile carriage 5. That is, the autonomous motion control unit 73 controls the mobile carriage 5 so that the service robot 1 moves along the route generated by the route generation unit 72. In addition, in an embodiment, the autonomous motion control unit 73 is configured to detect contact between the service robot 1 and surrounding objects using the robot arm 3 during the movement of the service robot 1. Therefore, as Figures 5 to 7 As illustrated in FIG, the autonomous motion control unit 73 controls the robot arm 3 or the moving bracket 5 so that during movement of the service robot 1 using the moving bracket 5, at least a portion or all of the robot arm 3 is positioned in front of the robot body 4 in the movement direction of the service robot 1. More specifically, the autonomous motion control unit 73 controls the robot arm 3 so that at least a portion or all of the robot arm 3 protrudes from the front of the moving bracket 5 in the movement direction of the service robot 1 in a plan view.

[0069] Back to Figure 4 The autonomous motion control unit 73 has multiple sensing modes. The multiple sensing modes include a first sensing mode 80, a second sensing mode 81, a third sensing mode 82, and a fourth sensing mode 83. The autonomous motion control unit 73 selects one of the multiple sensing modes based on the image data output from the camera 15 and the three-dimensional point cloud data output from the laser radar 16, and controls the posture of the robot arm 3 based on the selected sensing mode.

[0070] The first sensing mode 80 is a sensing mode for controlling the posture of the robot arm 3 so that the end effector 35 of the robot arm 3 is positioned above the upper end 4a of the robot body 4, as shown in FIG. Figure 5 As shown. The upper arm link 30 extends obliquely upward from the arm base 12, and the forearm link 31 extends upward in the vertical direction. For example, in a case where the drone-type delivery robot is flying in a service environment, there is a risk that the drone-type delivery robot comes into contact with the head 14 of the service robot 1. Therefore, in this case, it is necessary to protect the head 14 of the service robot 1. Therefore, the autonomous motion control unit 73 selects the first sensing mode 80, and controls the posture of the robot arm 3 based on the first sensing mode 80 so that the posture of the robot arm 3 becomes Figure 5 The posture shown. Figure 5The illustrated posture of the robot arm 3 is a specific example of the first posture.

[0071] like Figure 5 As shown, in the first sensing mode 80, the height position of the end effector 35 is the first height position H1. As described above, the first height position H1 is a position higher than the upper end 4a of the robot body 4. In the first sensing mode 80, the forearm link 31 extends in the vertical direction. Therefore, the sensing range SRI when the first sensing mode 80 is selected is a range corresponding to the link length of the forearm link 31 in the vertical direction.

[0072] The second sensing mode 81 is a sensing mode for controlling the posture of the robot arm 3 so that the end effector 35 of the robot arm 3 is positioned slightly below the upper end 4a of the robot body 4. Figure 6 As shown. The upper arm link 30 extends obliquely downward from the arm base 12, and the forearm link 31 extends upward in the vertical direction. For example, in a case where there are multiple pedestrians in the service environment, there is a risk that the pedestrians will come into contact with the service robot 1. Therefore, in this case, in order to prevent the robot arm 3 from coming into contact with the head of the pedestrian, the autonomous motion control unit 73 selects the second sensing mode 81, and controls the posture of the robot arm 3 based on the second sensing mode 81 so that the posture of the robot arm 3 becomes Figure 6 The posture shown. Figure 6 The illustrated posture of the robot arm 3 is a specific example of the second posture.

[0073] like Figure 6 As shown, in the second sensing mode 81, the height position of the end effector 35 is the second height position H2. The second height position H2 is lower than the first height position H1. As described above, the second height position H2 is slightly lower than the upper end 4a of the robot body 4. In the second sensing mode 81, the forearm link 31 extends in the vertical direction. Therefore, the sensing range SR2 when the second sensing mode 81 is selected corresponds to the vertical length of the forearm link 31.

[0074] The third sensing mode 82 is a sensing mode for controlling the posture of the robot arm 3 so that the end effector 35 of the robot arm 3 is positioned near the floor surface F in the service environment, as shown in FIG. Figure 7As shown. The upper arm link 30 extends obliquely downward from the arm base 12, and the forearm link 31 extends downward in the vertical direction. For example, in a case where the autonomous cleaning robot is operating in a service environment, there is a risk that the autonomous cleaning robot will come into contact with the mobile bracket 5 of the service robot 1. Therefore, in this case, in order to reduce the frequency of emergency stops of the service robot 1 due to contact between the autonomous cleaning robot and the mobile bracket 5, the autonomous motion control unit 73 selects the third sensing mode 82, and controls the posture of the robot arm 3 based on the third sensing mode 82 so that the posture of the robot arm 3 becomes Figure 7 The posture shown.

[0075] like Figure 7 As shown, in the third sensing mode 82, the height position of the end effector 35 is the third height position H3. The third height position H3 is lower than the first height position H1 and the second height position H2. As described above, the third height position H3 is located closer to the floor surface F. In the third sensing mode 82, the forearm link 31 extends in the vertical direction. Therefore, the sensing range SR3 when the third sensing mode 82 is selected corresponds to the vertical length of the forearm link 31.

[0076] like Figures 5 to 7 As shown, the sensing range SRI in the first sensing mode 80, the sensing range SR2 in the second sensing mode 81, and the sensing range SR3 in the third sensing mode 82 are set to have different heights from each other. In this way, in an embodiment, an appropriate sensing range can be flexibly set according to the surrounding environment.

[0077] like Figure 8 As shown, the fourth sensing mode 83 is a sensing mode for causing the robot arm 3 to swing left and right in a fan-shaped manner on the front surface side of the service robot 1. In this way, the autonomous motion control unit 73 causes the robot arm 3 to swing. Thereby, contact with surrounding objects can be detected in a wide range as viewed from the motion direction of the service robot 1. Figure 8 In the example of FIG. 1 , the autonomous motion control unit 73 causes the robot arm 3 to swing below the arm base 12 . However, the autonomous motion control unit 73 may cause the robot arm 3 to swing above the arm base 12 instead of this.

[0078] The autonomous motion control unit 73 performs collision mitigation control when an external force caused by contact with surrounding objects acts on the robot arm 3 during the movement of the service robot 1 using the moving bracket 5. Specifically, the autonomous motion control unit 73 can detect the above external force as an external force torque by monitoring the current values ​​of the shoulder joint actuator 40, the elbow joint actuator 41, and the wrist joint actuator 42. Instead of this, the autonomous motion control unit 73 can detect the action of the above external force based on the output value of an encoder set for the shoulder joint actuator 40, the elbow joint actuator 41, and the wrist joint actuator 42. In addition, a strain gauge can be attached to the upper arm link 30 or the forearm link 31, and the autonomous motion control unit 73 can detect the action of the above external force based on the output value of the strain gauge.

[0079] Typically, the above collision mitigation control is a control for reducing the movement speed of the service robot 1 or a control for changing the movement direction of the service robot 1. The above collision mitigation control may be a control for changing the movement direction of the service robot 1 while reducing the movement speed of the service robot 1. In an embodiment, the collision mitigation control is a control for changing the movement direction of the service robot 1.

[0080] Next, we will refer to Figure 9 The operation of the service robot 1 is described.

[0081] First, the destination setting unit 70 sets the destination (S100). Next, the self-position estimation unit 71 estimates the current position of the service robot 1 (S110). Next, the route generation unit 72 generates a route from the current position of the service robot 1 to the destination (S120). Next, the autonomous motion control unit 73 obtains the image data output from the camera 15 and the three-dimensional point cloud data output from the lidar 16 as environmental information (S130). Next, the autonomous motion control unit 73 selects a sensing mode based on the environmental information (S140). Specifically, in a case where a drone-type conveying robot is detected based on the environmental information, the autonomous motion control unit 73 selects the first sensing mode 80. In a case where a pedestrian is detected based on the environmental information, the autonomous motion control unit 73 selects the second sensing mode 81. In a case where an autonomous cleaning robot is detected based on the environmental information, the autonomous motion control unit 73 selects the third sensing mode 82. In other cases, the autonomous motion control unit 73 selects the fourth sensing mode 83.

[0082] Next, the autonomous motion control unit 73 starts autonomous motion along the route generated by the route generation unit 72, and controls the posture of the robot arm 3 based on the selected sensing mode (S150). Next, the self-position estimation unit 71 estimates the current position of the service robot 1 (S160). Next, the autonomous motion control unit 73 obtains the image data output from the camera 15 and the three-dimensional point cloud data output from the lidar 16 as environmental information (S170). Next, the autonomous motion control unit 73 selects a sensing mode based on the environmental information (S180). The autonomous motion control unit 73 can use a neural network to select a sensing mode after knowing that the sensing mode is output when receiving the environmental information. Next, in a case where the sensing mode selected in step S180 is different from the sensing mode currently being executed, the autonomous motion control unit 73 switches the sensing mode to be executed from now on to the sensing mode selected in step S180 (S190).

[0083] Next, the autonomous motion control unit 73 determines whether an external force caused by contact with a surrounding object has acted on the robot arm 3 during the movement of the service robot 1 using the moving bracket 5 (S200). In the case where the autonomous motion control unit 73 determines that an external force has acted, the autonomous motion control unit 73 causes the process to proceed to S210. On the other hand, in the case where the autonomous motion control unit 73 determines that an external force has not acted, the autonomous motion control unit 73 causes the process to proceed to S230.

[0084] Next, the autonomous motion control unit 73 changes the motion direction of the service robot 1 (S210). For example, while maintaining the motion speed of the service robot 1, the autonomous motion control unit 73 changes the motion direction of the service robot 1 by approximately 5 to 45 degrees to the right or left in a plan view. Since the robot arm 3 is reversibly drivable, the damage caused to surrounding objects is inherently small. Therefore, in an embodiment, the service robot 1 does not stop, and only a slight change in the motion direction of the service robot 1 is made. As a result, the service robot 1 can reach the destination ahead of time.

[0085] Next, the route generation unit 72 updates the route (S220). That is, the route generation unit 72 regenerates the route from the current position of the service robot 1 to the destination because the movement route of the service robot 1 has deviated from the pre-generated route as described above.

[0086] Next, the autonomous motion control unit 73 determines whether an external force caused by contact with surrounding objects has acted on the moving bracket 5 while the service robot 1 is moving using the moving bracket 5 (S230). In the case where the autonomous motion control unit 73 determines that an external force has acted, the autonomous motion control unit 73 performs an emergency stop of the movement of the service robot 1 (S240). On the other hand, in the case where the autonomous motion control unit 73 determines that an external force has not acted, the autonomous motion control unit 73 causes the process to proceed to S250.

[0087] Next, the autonomous motion control unit 73 determines whether the service robot 1 has arrived at the destination (S250). In the case where the autonomous motion control unit 73 determines that the service robot 1 has arrived at the destination, the autonomous motion control unit 73 ends the processing. In the case where the autonomous motion control unit 73 determines that the service robot 1 has not arrived at the destination, the autonomous motion control unit 73 returns the processing to S160.

[0088] In the case where the autonomous motion control unit 73 has executed the emergency stop of the motion of the service robot 1 as described above (S240), the autonomous motion control unit 73 notifies the operator of the emergency stop of the service robot 1. The operator rushes to the service robot 1 and determines whether the motion of the service robot 1 can continue. In the case where the operator determines that the motion of the service robot 1 can continue, the operator restarts the motion of the service robot 1.

[0089] The embodiments of the present disclosure have been described above. The above embodiments have the following features.

[0090] like Figure 1 、 Figure 4 and Figure 9 As shown, the service robot 1 (autonomous mobile object) includes a reversibly drivable robot arm 3, a robot body 4 supporting the robot arm 3, a mobile bracket 5 provided at the lower portion of the robot body 4, and a control unit 6 for controlling the robot arm 3 and the mobile bracket 5. The control unit 6 performs collision mitigation control when an external force generated by contact with surrounding objects acts on the robot arm 3 during movement of the service robot 1 using the mobile bracket 5. In the above configuration, the detection of the collision is performed by the reversibly drivable robot arm 3, and the reversibly drivable robot arm does not cause significant damage to the surrounding objects at the moment of contact with the surrounding objects. Therefore, in the above configuration, the service robot 1 can move at a higher speed compared to the case in which the collision detection is performed by the buffer 21. In addition, since no significant damage is caused to the surrounding objects, there are fewer restrictions when generating the movement route of the service robot 1, and, for example, there is no need to select an indirect route in which the number of pedestrians is very small.

[0091] In addition, if Figure 9 As shown, the collision mitigation control is a control (S210) for changing the moving direction of the service robot 1. With this configuration, the service robot 1 can avoid surrounding objects without reducing its moving speed.

[0092] In addition, for example, Figure 5 As shown, the control unit 6 controls the robot arm 3 and the moving bracket 5 so that the robot arm 3 is positioned in front of the robot body 4 in the movement direction of the service robot 1 during movement of the service robot 1 using the moving bracket 5. With this configuration, contact between the service robot 1 and surrounding objects can be effectively detected.

[0093] In addition, for example, Figure 5 As shown, the control unit 6 controls the robot arm 3 so that the robot arm 3 projects in front of the moving bracket 5 in the moving direction of the service robot 1 in a plan view. With this configuration, contact between the service robot 1 and surrounding objects can be effectively detected.

[0094] In addition, for example, Figures 5 to 7 As shown, the control unit 6 has a plurality of sensing modes including a first sensing mode 80 and a second sensing mode 81. In the first sensing mode 80, the posture of the robot arm 3 is Figure 5 The first posture shown, in the second sensing mode 81, the posture of the robot arm 3 is Figure 5 The first posture shown is different Figure 6 The control unit 6 selects one of the plurality of sensing modes. The control unit 6 controls the posture of the robot arm 3 based on the selected sensing mode. With the above configuration, different sensing ranges can be achieved.

[0095] In addition, if Figure 4 and Figure 9 As shown, the service robot 1 also includes a camera 15 and a laser radar 16 (surrounding environment monitoring unit) for monitoring the surrounding environment. The control unit 6 selects one of multiple sensing modes (S130, S140, S170, S180, S190) based on the surrounding environment. With the above configuration, the optimal sensing mode can be selected according to the surrounding environment.

[0096] exist Figure 5 In the first posture shown, the height position of the end effector 35 of the robot arm 3 is the first height position H1. Figure 6 In the second posture shown, the height position of the end effector 35 of the robot arm 3 is a second height position H2 different from the first height position H1. With the above configuration, sensing can be performed in a range different from that in the vertical direction.

[0097] In addition, for example, Figure 8 As shown, the control unit 6 can swing the robot arm 3 in a fan-shaped manner during movement of the service robot 1 using the moving bracket 5. With this configuration, wide-range sensing is achieved.

[0098] In addition, for example, Figure 2 As shown, the robot arm 3 includes an upper arm link 30 and a forearm link 31 (at least two links) and an elbow joint 33 (joint) connecting the upper arm link 30 and the forearm link 31. The service robot 1 also includes an elbow joint actuator 41 (actuator) arranged in the arm base 12 of the robot body 4 and driving the elbow joint 33, and an annular belt 31b (dynamic power transmission mechanism) that transmits the dynamic power generated by the elbow joint actuator 41 to the elbow joint 33. By utilizing the above configuration, the robot arm is lightweight. Therefore, when the robot arm 3 of the service robot 1 contacts the surrounding objects, it will not cause significant damage to the surrounding objects. In addition, by utilizing the above configuration, the reverse driving capability of the robot arm 3 is achieved at a high level.

[0099] Furthermore, as the dynamic power transmission mechanism, for example, an endless belt 31b or a wire 35b may be employed. With this configuration, the robot arm 3 is made lightweight at a high level.

[0100] Furthermore, the control unit 6 performs impedance control of the robot arm 3. With this configuration, a back-drivable robot arm 3 can be realized by simple control.

[0101] In addition, if Figure 4 and Figure 9 As shown, the service robot 1 further includes a bumper sensor 25 (contact sensor) that detects that a surrounding object has come into contact with the moving bracket 5 during movement of the service robot 1 using the moving bracket 5. The control unit 6 can also stop the movement of the service robot 1 (S240) when the bumper sensor 25 detects that a surrounding object has come into contact with the moving bracket 5. With the above configuration, the movement of the service robot 1 can be stopped when the moving bracket 5 has come into contact with a surrounding object.

[0102] In addition, if Figure 9 As shown, the control method for the service robot 1 includes: starting the autonomous movement of the service robot 1 using the mobile bracket 5 (S150); and performing collision mitigation control (S210) when an external force caused by contact with a surrounding object acts on the robot arm 3 during the movement of the service robot 1 using the mobile bracket 5. Through the above method, high-speed movement of the service robot 1 is achieved.

[0103] First modification

[0104] Next, we will refer to Figure 10Description of First Modification: The following will mainly describe points where the modification differs from the above embodiment, and duplicate descriptions will be omitted.

[0105] Figure 10 FIG. 1 shows a plan view of the service robot 1. Figure 10 As shown, the robot arm 3 is positioned in front of the robot body 4 in the movement direction of the service robot 1. Figure 10 In the plan view, the forearm link 31 of the robot arm 3 is positioned in front of the moving bracket 5 in the moving direction of the service robot 1. In addition, the forearm link 31 extends in a direction orthogonal to the moving direction of the service robot 1 in the plan view and has a horizontally extended posture. With the above configuration, the sensing range in the width direction of the service robot 1 can be expanded. In addition, as Figure 10 As shown, the link length of the forearm link 31 may be longer than the diameter of the moving bracket 5. With this configuration, a wider sensing range in the width direction of the service robot 1 may be achieved.

[0106] Second modification

[0107] Next, we will refer to Figure 11 Description of Second Modification: The following will mainly describe points where the modification differs from the above embodiment, and duplicate descriptions will be omitted.

[0108] like Figure 11 As shown, steps S100 to S200 are consistent with the steps in the above embodiment, and thus description is omitted.

[0109] The autonomous motion control unit 73 determines whether an external force caused by contact with surrounding objects has acted on the robot arm 3 during the movement of the service robot 1 using the moving bracket 5 (S200). In the case where the autonomous motion control unit 73 determines that an external force has acted, the autonomous motion control unit 73 causes the processing to proceed to S300. In step S300, the autonomous motion control unit 73 reduces the movement speed of the service robot 1 (S300). When the service robot 1 is decelerated in this manner, there is a possibility that the surrounding objects deviate from the direction of travel of the service robot 1 while in contact with the service robot 1, and thereby release the contact state. Therefore, compared with the case of an emergency stop of the service robot 1, the movement speed of the service robot 1 can be maintained to a certain extent. Therefore, the service robot 1 can arrive at the destination ahead of time.

[0110] In the above second modification, in the case where the autonomous motion control unit 73 determines that an external force has acted (S200), the autonomous motion control unit 73 may temporarily reduce the motion speed of the service robot 1. Temporarily reducing the motion speed of the service robot 1 means restoring the motion speed to the speed before the reduction when a predetermined time has passed after the motion speed of the service robot 1 has been reduced, or when a predetermined condition is satisfied after the motion speed of the service robot 1 has been reduced.

[0111] In the above second modification, in the case where the autonomous motion control unit 73 determines that an external force has acted (S200), the autonomous motion control unit 73 can non-temporarily reduce the motion speed of the service robot 1. The so-called non-temporary reduction of the motion speed of the service robot 1 means that after the motion speed of the service robot 1 is reduced, the motion speed does not, in principle, return to the speed before the reduction. It has been found that the environment in which the service robot 1 is currently moving is an environment in which there is a risk of contact between surrounding objects and the robot arm 3 during the movement of the service robot 1 using the moving bracket 5. Therefore, after the above determination, regardless of whether an external force is applied, an operation in which the motion speed of the service robot 1 is reduced to a predetermined degree is possible.

[0112] The first and second modifications have been described above. The above embodiment can be further modified as follows.

[0113] For example, the control unit 6 may change the control parameter for impedance control of the robot arm 3 according to the movement speed of the service robot 1. Generally, the control parameter for impedance control means an inertia coefficient, a viscous efficiency, or a stiffness coefficient.

[0114] In addition, as a dynamic power transmission mechanism for transmitting the dynamic power generated by the elbow joint actuator 41 to the elbow joint 33, a link mechanism may be used instead of Figure 2 and Figure 3 The organization shown.

[0115] The third modification

[0116] Next, we will refer to Figure 12 Description of Third Modification: The following will mainly describe points where the modification differs from the above embodiment, and duplicate descriptions will be omitted.

[0117] In the above embodiments, Figure 1 As shown, the control unit 6 is included in the service robot 1. That is, the control system 100 including the service robot 1 and the control unit 6 is realized by only the service robot 1.

[0118] In contrast, in the modification, the control system 300 includes a service robot 1 and a control device 200. The service robot 1 and the control device 200 are constructed separately. The service robot 1 and the control device 200 are constructed so that two-way communication is possible. In addition, the control device 200 performs Figure 4 Some or all of the functions of the control unit 6 shown. That is, Figure 4 The control unit 6 shown is implemented by distributed processing by the service robot 1 and the control device 200. In this case, for example, the control unit 6 of the service robot 1 determines whether an external force caused by contact with surrounding objects has acted on the robot arm 3 during the movement of the service robot 1 using the moving bracket 5, and the control unit 6 of the service robot 1 sends the determination result to the control device 200. The control device 200 determines whether it is necessary to perform collision mitigation control based on the determination result received from the service robot 1. In the case where the control device 200 determines that collision mitigation control is required, the control device 200 sends a collision mitigation control instruction to the service robot 1. The control unit 6 of the service robot 1 performs a predetermined collision mitigation control upon receiving the collision mitigation control instruction from the control device 200.

[0119] In the above modification, the control unit 6 of the service robot 1 determines whether an external force caused by contact with surrounding objects has acted on the robot arm 3 during the movement of the service robot 1 using the mobile bracket 5, but the present disclosure is not limited thereto. Sensor signals of various sensors included in the service robot 1 may also be sent to the control device 200 in real time. The control device 200 can determine whether an external force caused by contact with surrounding objects has acted on the robot arm 3 during the movement of the service robot 1 using the mobile bracket 5 based on the received sensor signals.

[0120] Fourth modification

[0121] Next, a fourth modification will be described. The following will mainly describe points where the modification differs from the above embodiment, and duplicate descriptions will be omitted.

[0122] In the above embodiment, the collision relaxation control is, as an example, a control to reduce the movement speed of the service robot 1 or a control to change the movement direction of the service robot 1. However, the collision relaxation control is not limited thereto.

[0123] For example, the collision mitigation control may be a control to stop the motion of the service robot 1 .

[0124] In addition, the control unit 6 can perform collision mitigation control under the following conditions: during the movement of the service robot 1 using the mobile bracket 5, the control unit 6 determines that the external force caused by the contact with the surrounding objects has acted on the robot arm 3 a predetermined number of times. With this configuration, the execution frequency of the collision mitigation control can be suppressed, and priority can be given to the movement of the service robot 1. In this way, the execution timing of the collision mitigation control is not limited to the time point when it is determined that the external force generated by the contact with the surrounding objects has acted on the robot arm 3 during the movement of the service robot 1 using the mobile bracket 5, and can be a time point after the determined time point. The reason why the collision mitigation control does not need to be executed immediately at the time point when it is determined that the external force generated by the contact with the surrounding objects has acted on the robot arm 3 during the movement of the service robot 1 using the mobile bracket 5 in this way is because the robot arm 3 is configured to be reversibly drivable.

[0125] In the above examples, various types of non-transient computer-readable media can be used to store the program and provide the program to the computer. Non-transient computer-readable media include various types of tangible recording media. Examples of non-transient computer-readable media include magnetic recording media (e.g., floppy disks, magnetic tapes, and hard disk drives) and magneto-optical recording media (e.g., magneto-optical disks). Examples of non-transient computer-readable media also include CD-read-only memories (ROMs), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs). Examples of non-transient computer-readable media also include programmable ROMs (PROMs), erasable PROMs (EPROMs), flash ROMs, and random access memories (RAMs). In addition, the program can be provided to the computer by various types of transient computer-readable media. Examples of transient computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transient computer-readable media can provide the program to the computer via a wired communication path such as an electric wire and an optical fiber or via a wireless communication path.

Claims

1. A control system comprising: An autonomous moving object, the autonomous moving object comprising: Back-drivable robotic arm, a robot body supporting the robot arm, and a moving bracket provided at a lower portion of the robot body; and A control unit configured to perform collision mitigation control in response to an external force acting on the robot arm during movement of the autonomous moving object using the moving bracket, the external force being caused by contact with surrounding objects.

2. The control system according to claim 1, wherein: The collision mitigation control is a control for changing the moving direction of the autonomous moving object.

3. The control system according to claim 1, wherein: The collision mitigation control is a control for reducing the movement speed of the autonomous moving object.

4. The control system according to claim 1, wherein: The control unit is configured to control the robot arm or the moving bracket so that the robot arm is positioned forward of the robot body in a moving direction of the autonomous moving object during movement of the autonomous moving object using the moving bracket.

5. The control system according to claim 4, wherein: The control unit is configured to control the robot arm so that the robot arm protrudes from the front of the moving bracket in a moving direction of the autonomous moving object in a plan view.

6. The control system according to claim 1, wherein: The control unit is configured to have multiple sensing modes including at least a first sensing mode and a second sensing mode to select one of the multiple sensing modes, and the control unit controls the posture of the robot arm based on the selected sensing mode, the first sensing mode is a sensing mode in which the posture of the robot arm is a first posture, and the second sensing mode is a sensing mode in which the posture of the robot arm is a second posture different from the first posture.

7. The control system according to claim 6, wherein: The autonomous mobile object further includes a surrounding environment monitoring unit configured to monitor the surrounding environment; and The control unit is configured to select one of the plurality of sensing modes based on the surrounding environment.

8. The control system according to claim 6 or 7, wherein: In the first posture, the height position of the end effector of the robot arm is a first height position; and In the second posture, the height position of the end effector of the robotic arm is a second height position different from the first height position.

9. The control system according to claim 1, wherein: The control unit is configured to swing the robot arm in a fan-shaped manner during movement of the autonomous moving object using the moving bracket.

10. The control system of claim 1, wherein: The robotic arm comprises: At least two connecting rods, and a joint connecting the at least two links; and The autonomous moving object further comprises: an actuator configured to drive the joint, the actuator being disposed in the robot body, and A dynamic power transmission mechanism is configured to transmit dynamic power generated by the actuator to the joint.

11. The control system according to claim 10, wherein: The dynamic power transmission mechanism includes a belt or a wire.

12. The control system according to claim 1, wherein: The control unit is configured to perform impedance control of the robotic arm.

13. The control system according to claim 1, further comprising a contact sensor configured to detect that the surrounding object has come into contact with the moving bracket during movement of the autonomous moving object using the moving bracket, wherein The control unit is configured to stop the movement of the autonomous moving object when the contact sensor has detected that the surrounding object has come into contact with the moving bracket.

14. A control method for autonomously moving an object, The autonomous moving object includes: Back-drivable robotic arm, a robot body supporting the robot arm, and A movable bracket is provided at a lower portion of the robot body, and the control method includes: Using the moving bracket to move the autonomous moving object; and Collision mitigation control is performed in response to an external force acting on the robot arm during movement of the autonomous moving object using the moving bracket, the external force being caused by contact with surrounding objects. 15 . A storage medium storing instructions that are executable by one or more processors of a computer and cause the one or more processors to perform functions including the control method according to claim 14 .

Images