Slave robot, fall prevention method, and robot system

Abstract

This system prevents the slave robot from tipping over even if the operator makes a mistake and the robot is about to fall. [Solution] A slave robot whose posture changes according to a command value determined in response to a change in the posture of a master robot is equipped with a command value control unit that reduces the command value to prevent the slave robot from falling over if the slave robot is about to fall over. By reducing the command value to prevent the slave robot from falling over when it is about to fall over, it is possible to prevent the slave robot from falling over even if the slave robot is about to fall over and the operator makes a mistake.

Description

【Technical Field】 【0001】 The technology of the present disclosure relates to a slave robot, a fall prevention method, and a robot system. 【Background Art】 【0002】 Conventionally, a robot system has been proposed that includes a master robot and a slave robot that changes its posture according to a command value determined according to the posture change of the master robot. When the slave robot changes its posture according to the above command value, the slave robot may be about to fall. There are Patent Documents 1 and 2 as related patent documents. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2006-150567 【Patent Document 2】 Japanese Patent Application Laid-Open No. 2015-134384 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 However, when the slave robot is about to fall, the operator of the master robot who sees this will be confused and panicked because they are making movements different from their intended movements, and may misoperate the master robot in a direction where it is more likely to fall. As a result, there is a risk that the slave robot will fall. 【0005】 An object of the technology of the present disclosure is to provide a slave robot, a fall prevention method, and a robot system that can prevent the slave robot from falling even when the slave robot is about to fall and the operator makes a misoperation. 【Means for Solving the Problems】 【0006】 To achieve the above objective, a first aspect of the technology of this disclosure is a slave robot whose posture changes in response to a change in the posture of a master robot via a command system with the master robot, wherein if the slave robot is about to fall over, the slave robot disconnects the command system or reduces the influence from the master robot to a degree that is less than when the slave robot is not about to fall over. 【0007】 A second aspect is a method for preventing a slave robot from tipping over, which changes its posture in response to a change in the posture of a master robot via a command system between the master robot and the slave robot, wherein when the slave robot is about to tip over, the command system is disconnected or the influence from the master robot is reduced compared to when the slave robot is not about to tip over. 【0008】 A third embodiment is a robot system comprising a master robot and a slave robot whose posture changes in response to a change in the posture of the master robot via a command system between the master robot and the slave robot, wherein if the slave robot is about to fall over, the command system is disconnected or the influence from the master robot is reduced compared to when the slave robot is not about to fall over. [Effects of the Invention] 【0009】 In the first to third aspects of the technology of this disclosure, when the slave robot is about to fall over, the command value is reduced by disconnecting the command system or by reducing the influence from the master robot to a level greater than when the slave robot is not about to fall over. This prevents the slave robot from falling over even if it is about to fall over and the operator makes a mistake. [Brief explanation of the drawing] 【0010】 [Figure 1] Figure 1 is a block diagram of an example of a robot system 100. [Figure 2]Figure 2 shows an example of the postures of the master robot arm 10 and the slave robot arm 20 when the slave robot 2040 is remotely controlled by an operator operating the master robot arm 10. [Figure 3] Figure 3 is a block diagram of an example of the electrical system of the slave robot 2040. [Figure 4] Figure 4 shows an example of the processing performed by the calculation unit 52C, the determination unit 52D, and the disconnection unit 52E of the processor 52. [Figure 5] Figure 5 is a flowchart of an example of a fall prevention program 54P executed by the processor 52 of the slave robot controller 40. [Figure 6] Figure 6 shows an example of the display screen 62MD of the display device of the master robot controller 30, which displays information indicating that there is a risk of the slave robot 2040 tipping over. [Modes for carrying out the invention] 【0011】 [Embodiment] Embodiments of the technology of this disclosure will be described below with reference to the drawings. 【0012】 [Embodiment] (composition) The configuration of the robot system 100 of this embodiment will now be described. Figure 1 is a block diagram of an example of the robot system 100. As shown in Figure 1, the robot system 100 comprises a master robot 1030 and a slave robot 2040 whose posture changes according to a command value determined in accordance with the posture change of the master robot 1030. The master robot 1030 comprises a master robot arm 10 and a master robot controller 30. The slave robot 2040 comprises a slave robot arm 20 and a slave robot controller 40. 【0013】 When remotely controlling the slave robot 2040, the operator controls the master robot arm 10, and the master robot controller 30 transmits the angle and torque information of the master robot arm 10 at that time as command values ​​to the slave robot controller 40 via wireless or wired communication. The slave robot controller 40 then controls the slave robot arm 20 so that its posture changes according to the received command values. In this way, the slave robot arm 20 acts on the environment. 【0014】 In this embodiment of the robot system 100, the master robot controller 30 and the slave robot arm 20 communicate bidirectionally with each other. As a result, the slave robot controller 40 transmits information on the angle and torque of the slave robot to the master robot controller 30 via wireless or wired communication. The master robot controller 30 controls the master robot arm 10 so that its posture changes according to this information. Thus, when an operator remotely controls the slave robot 2040 by operating the master robot arm 10, the master robot arm 10 and the slave robot arm 20 will be in the same posture. Furthermore, the technology of this disclosure may also be applied when one-way communication is performed from the master robot controller 30 to the slave robot arm 20. 【0015】 FIG. 2 is a diagram showing an example of the postures of the master robot arm 10 and the slave robot arm 20 when the operator remotely operates the slave robot 2040 by operating the master robot arm 10. As shown in FIG. 2, the master robot arm 10 includes arm portions 10p1 to 10p6 connected by a plurality of joints J11 to J15. The slave robot arm 20 includes arm portions 20p1 to 20p6 connected by a plurality of joints J21 to J25. The master robot arm 10 and the slave robot arm 20 have the same configuration. For example, the arm portions 10p1 to 10p6 of the master robot arm 10 and the arm portions 20p1 to 20p6 of the slave robot arm 20 have the same configuration, members of the same material, the same shape, and the same length. 【0016】 In the present embodiment, the arm portion 10p1 on the proximal end side of the master robot arm 10 is fixed to a fixing body 10K fixed to the floor. The arm portion 20p1 on the proximal end side of the slave robot arm 20 is fixed to a moving body 20M to which wheels 20W1 and 20W2 are attached on the lower side. 【0017】 FIG. 3 is a block diagram of an example of the electrical system of the slave robot 2040. As shown in FIG. 3, each of the joints J21 to J25 of the slave robot arm 20 includes a motor 22, an encoder 24, and a torque sensor 26. 【0018】 The slave robot controller 40 includes a computer 50, a display device 62, and a communication device 64. The computer 50 includes a processor 52, a non-volatile memory (NVM) 54, a random access memory (RAM) 56, and an input / output (I / O) port 58. The processor 52, the NVM 54, the RAM 56, and the input / output (I / O) port 58 are interconnected by a bus 60. To the input / output (I / O) port 58, the motors 22, the encoders 24, and the torque sensors 26 of each of the joints J21 to J25 of the slave robot arm 20, the display device 62, and the communication device 64 are connected. 【0019】 The processor 52 is a processing device including a DSP (Digital Signal Processor), a CPU (Central Processing Unit), and a GPU (Graphics Processing Unit). The DSP and the GPU operate under the control of the CPU and are responsible for executing each of the processes described later. Here, as an example of the processor 52, a processing device including a DSP, a CPU, and a GPU is given, but this is merely an example. The processor 32 may be one or more CPUs and DSPs integrating the GPU function, or one or more CPUs and DSPs not integrating the GPU function, or a TPU (Tensor Processing Unit) may be mounted. 【0020】 The NVM 54 is a non-volatile storage device that stores programs and various parameters, etc. Examples of the NVM 54 include a flash memory (for example, an EEPROM (Electrically Erasable and Programmable Read Only Memory)). The NVM 54 stores an anti-tipping program 54P and a threshold value 54T. 【0021】 The RAM 56 is a memory in which information is temporarily stored and is used as a work memory by the processor 52. Examples of the RAM 56 include a DRAM (Dynamic Random Access Memory) or a SRAM (Static Random Access Memory), etc. 【0022】 When the anti-tipping program 54P is read into the RAM 36 and executed by the processor 52, the processor 52 functions as a receiving unit 52A, an operating unit 52B, a calculating unit 52C, a determining unit 52D, a cutting unit 52E, and a notification unit 52F. 【0023】 Since the electrical system of the master robot 1030 is the same as that of the slave robot 2040, the description thereof is omitted. 【0024】 Figure 4 shows an example of the processing performed by the calculation unit 52C, the determination unit 52D, and the disconnection unit 52E of the processor 52. As shown in Figure 4, the calculation unit 52C calculates the ZMP, which will be described later. The determination unit 52D reads the threshold 54T from the NVM 54 and determines whether the calculated ZMP exceeds the threshold 54T. If it is determined that the ZMP exceeds the threshold 54T, the disconnection unit 52E reduces the command value from the master robot controller 30 to a small value, specifically to zero, so that the slave robot 2040 does not fall over. More specifically, it disconnects the command system between the master and the slave. 【0025】 (action) Next, the operation of this embodiment will be explained. 【0026】 When remotely controlling the slave robot 2040, the operator controls the master robot arm 10, and the master robot controller 30 transmits information on the angle and torque of the master robot arm 10 at that time as command values ​​to the slave robot controller 40 via wireless or wired communication. 【0027】 Figure 5 is a flowchart of an example of a fall prevention program 54P executed by the processor 52 of the slave robot controller 40. The fall prevention program 54P starts when a start button (not shown) is operated. When the processor 52 executes the fall prevention program 54P, the fall prevention process and fall prevention method are executed. 【0028】 In step 72, the receiving unit 52A receives the above command value from the master robot controller 30. 【0029】 In step 74, the operating unit 52B controls the motors 22 of each joint J21 to J25 of the slave robot arm 20 so that the posture of the slave robot arm 20 changes according to the command value. 【0030】 In step 76, the calculation unit 52C calculates the ZMP. The ZMP is the point where the resultant force T12 of the inertial torque T1 (see also Figure 2) of the slave robot 2040 during its operation and the torque T2 generated on the slave robot 2040 due to gravity intersects with the floor. This point is the dynamic center of gravity, i.e., the zero moment point. The inertial torque of the slave robot 2040 during its operation is calculated from the values ​​detected by the torque sensors 26 at each joint J21 to J25 of the slave robot arm 20. The torque generated on the slave robot 2040 due to gravity is calculated from the size, weight, and position of the arm sections 20p1 to 20p6 of the slave robot arm 20. 【0031】 In step 78, the determination unit 52D reads the threshold 54T from the NVM 54 and determines whether the ZMP calculated in step 76 exceeds the threshold 54T, thereby determining whether the slave robot 2040 is about to tip over. 【0032】 Here, the threshold 54T is determined by the dynamic center of gravity position at which the slave robot 2040 is about to tip over. Specifically, the threshold 54T may be the dynamic center of gravity position (i.e., the limit value) at which the slave robot 2040 is about to tip over, but it is a position that is a predetermined value smaller than that limit value so that the slave robot 2040 does not tip over. More specifically, the threshold 54T is based on the state in which the mobile body 20M tilts, but the slave robot 2040 does not tip over. 【0033】 If it is determined that ZMP has exceeded the threshold of 54T, the anti-tipping process returns to step 72 and executes the above processes (steps 72-78). If it is determined that ZMP has exceeded the threshold of 54T, the anti-tipping process proceeds to step 80. 【0034】 In step 80, the cutting unit 52E reduces the above command value to a small value, specifically to zero, so that the slave robot 2040 does not fall over. More specifically, it cuts the command system between the master and the slave. Here, the information that is cut off is the command system information, specifically the information used to change the attitude between the master robot controller 30 and the slave robot controller 40, while information used to control attitude, such as temperature, is not cut off. 【0035】 The cutting section 52E is an example of a "command value control unit" of the technology disclosed herein. Furthermore, the phrase "reducing the influence from the master robot to a level less than that in the case where the slave robot is unlikely to tip over," as described in claim 1, means, for example, correcting (for example reducing) the command value from the master robot so that the slave robot does not tip over. 【0036】 In step 82, the notification unit 52F notifies the operator of the master robot that the slave robot 2040 is at risk of tipping over. Specifically, the notification unit 52F transmits information that the slave robot 2040 is at risk of tipping over to the communication device of the master robot controller 30 via the communication device 64. The communication device of the master robot controller 30 receives this information, and the processor of the master robot controller 30 displays the information that the slave robot 2040 is at risk of tipping over on the display device, as shown in Figure 6. Figure 6 is a diagram showing an example of the display screen 62MD of the display device of the master robot controller 30 that displays information that the slave robot 2040 is at risk of tipping over. This information may include, for example, "The slave robot was cut off due to a risk of tipping over." 【0037】 The display device of the master robot controller 30 is an example of the "notification unit" of the technology disclosed herein. It should be noted that the notification of a risk of the slave robot 2040 tipping over is not limited to a display; it may also be notified by an audible warning. 【0038】 As shown in Figure 6, the operator of the master robot can see the above information displayed on the display screen 62MD of the master robot controller 30 and know that the slave robot 2040 is at risk of tipping over. 【0039】 In this embodiment, as shown in Figure 6, the restart button 62B is also displayed on the display screen 62MD. When the operator of the master robot operates the restart button 62B, a restart instruction is sent to the master robot controller 30. Upon receiving the restart instruction, the master robot controller 30 sends a restart instruction signal to the communication device 64 of the slave robot controller 40 via the communication device. As a result, the slave robot controller 40 is also instructed to restart. 【0040】 When a restart command is issued to the slave robot controller 40, the position adjustment unit of the processor 52 controls the motors 22 of each joint J21 to J25 of the slave robot arm 20 so that the slave robot 2040 assumes a predetermined posture that prevents it from falling over. 【0041】 Similarly, the master robot controller 30, which has been instructed to restart, controls the motors of each joint J11 to J15 of the master robot arm 10 so that the slave robot 2040 assumes a predetermined posture that prevents it from falling over. 【0042】 Thus, when a restart command is issued, the slave robot 2040 assumes a predetermined posture that prevents it from tipping over, and the master robot arm 10 also assumes a posture that corresponds to the predetermined posture that prevents the slave robot 2040 from tipping over. 【0043】 The predetermined posture is the initial position (i.e., home position) of the slave robot 2040 and the master robot arm 10, respectively. 【0044】 The position adjustment unit of the processor 52 of the slave robot controller 40 is an example of the "position adjustment unit" of the technology disclosed herein. 【0045】 (effect) As described above, in this embodiment, if the slave robot 2040 is about to fall over, the cutting unit 52E reduces the command value from the master robot controller 30 to prevent the slave robot 2040 from falling over. Specifically, it reduces it to zero, or more specifically, it cuts the command system between the master and the slave. 【0046】 In this regard, with conventional technology, if the slave robot is about to fall over, the operator of the master robot 1030, seeing this, may become confused and panicked because the robot is moving in a direction different from what was intended, and may mistakenly operate the master robot in a direction that makes it more likely to fall, resulting in the slave robot falling over. However, in this embodiment, even if the operator of the master robot makes a mistake, the command system between the master and slave is disconnected, so it is possible to prevent the slave robot 2040 from falling over. 【0047】 In the robot system 100 of this embodiment, the master robot controller 30 and the slave robot controller 40 communicate bidirectionally with each other. Specifically, the slave robot 2040 changes its posture according to a command value determined in response to the posture change of the master robot 1030, and the master robot 1030 changes its posture in response to the posture change of the slave robot 2040. As a result, when an operator remotely controls the slave robot 2040 by operating the master robot arm 10, the master robot arm 10 and the slave robot arm 20 will be in the same posture. Therefore, when the slave robot 2040 tilts, the master robot 1030 also tilts in the same way as the slave robot 2040. The operator may become confused and panic because the master robot 1030 is moving differently than intended, and may mistakenly operate the master robot 1030 in a direction that is more likely to tip over. However, even if the operator of the master robot makes a mistake, the command system between the master and slave is disconnected, so even if the master robot controller 30 and the slave robot controller 40 communicate bidirectionally with each other, it is possible to prevent the slave robot 2040 from tipping over. 【0048】 In this embodiment, if the ZMP, which takes into account the inertial torque during the operation of the slave robot 2040, exceeds the threshold 54T, the disconnection unit 52E disconnects the command system between the master and slave. Therefore, compared to comparing the center of gravity position and the threshold without considering the inertial torque during the operation of the slave robot 2040, it is possible to appropriately determine whether the slave robot 2040 is in a state where it is likely to tip over by taking into account the operation of the slave robot 2040. 【0049】 In this embodiment, the notification unit 52F notifies the slave robot 2040 that a risk of tipping over has occurred. This prevents the notified operator from making a mistake. In particular, when a risk of tipping over occurs in the slave robot 2040, the display screen 62MD of the master robot controller 30 displays the message, "The robot was disconnected because there was a risk of tipping over." Thus, the operator can find out why the slave robot 2040 did not change its posture as intended by the operator. 【0050】 In this embodiment, when a restart command is issued, both the slave robot 2040 and the master robot arm 10 return to the same initial position (i.e., home position). Therefore, both the slave robot 2040 and the master robot arm 10 can be positioned in the safest possible location, preventing the slave robot 2040 from tipping over. 【0051】 In this embodiment, if the slave robot 2040 is about to tip over, the cutting unit 52E sets the command value from the master robot controller 30 to zero. This prevents the slave robot 2040, which is already about to tip over, from tipping over even further. 【0052】 [Differentiation] Next, a modified example of this embodiment will be described. Since the configuration of each deformable part is the same as in the above embodiment, its description will be omitted, and the operation and effects will be described mainly. 【0053】 (First variation) In the above embodiment, torque information is obtained from the torque sensor 26, but torque estimated from the motor 22 and encoder 24 may also be used. 【0054】 (Second variation) In the above embodiment, when a restart command is issued, each of the slave robot arm 20 and the master robot arm 10 returns to its initial position (i.e., home position). The technology of this disclosure is not limited thereto. 【0055】 Firstly, the master robot arm 10 may be positioned to match the position of the slave robot arm 20 when it was determined that the slave robot 2040 was about to tip over. This allows the master robot arm 10 to return to the position in which the slave robot arm 20 was working just before, making it easier to resume the next task. Secondly, the slave robot arm 20 may be positioned to match the position of the master robot arm 10 when it is determined that the slave robot 2040 is about to fall over. This ensures that the master robot arm 10, which is controlled by the operator, does not move, thus preventing the operator from feeling any discomfort. 【0056】 (Third variation) In the above embodiment, there is only one threshold, but the technology of this disclosure is not limited thereto. Multiple thresholds may be predetermined, and the command value may be gradually reduced each time the ZMP exceeds each threshold. In other words, the influence from the master robot 1030 is reduced compared to when the slave robot 2040 is not likely to tip over. The multiple thresholds include the dynamic center of gravity position (i.e., the limit value) when the slave robot 2040 is likely to tip over, and positions that are gradually reduced from that limit value. As the multiple thresholds are exceeded in sequence, the command value gradually decreases, so that the change in posture of the slave robot 2040 gradually slows down, and the operator can know that the slave robot 2040 is gradually likely to tip over. This can further suppress erroneous operation and more safely prevent the slave robot 2040 from tipping over. 【0057】 (Fourth variation) In the above embodiment, ZMP is calculated as the target for comparison with a threshold, but the technology of this disclosure is not limited thereto, and the center of gravity position may be calculated without considering the inertial torque during the operation of the slave robot 2040. Since the inertial torque during the operation of the slave robot 2040 is not considered, the amount of computation can be reduced, the load on the processor 52 can be reduced, and power consumption can be reduced. 【0058】 (Fifth variation) In the above embodiment, the processor 52 of the slave robot controller 40 functions as a calculation unit 52C, a decision unit 52D, and a cutting unit 52E. The technology of this disclosure is not limited thereto. Firstly, the processor of the master robot controller 30 may function as a calculation unit 52C, a decision unit 52D, and a cutting unit 52E. If the slave robot 2040 is about to tip over, the command value from the master robot controller 30 is reduced to prevent the slave robot 2040 from tipping over, allowing the master robot controller 30 to take action faster than the slave robot controller could. Secondly, a separate computer processor, neither the slave robot controller 40 nor the master robot controller 30, may function as the calculation unit 52C, the decision unit 52D, and the cutting unit 52E. This reduces the load on the processors of both the slave robot controller 40 and the master robot controller 30. 【0059】 (Other variations) The technology disclosed herein can also be applied to remotely operated robots that transport cargo, provided that the center of gravity of the cargo is taken into consideration. 【0060】 [Note] Based on the above disclosures, the following addendum is proposed. 【0061】 (Note 1) A slave robot whose posture changes in response to changes in the posture of the master robot via a command system between the slave robot and the master robot, A slave robot that, when it is about to fall over, disconnects the command system or reduces the influence from the master robot compared to when the slave robot is not about to fall over. 【0062】 (Note 2) The master robot changes its posture in response to the change in posture of the slave robot. The slave robot described in Appendix 1. 【0063】 (Note 3) Based on the inertial torque of the slave robot during its operation, it is determined whether or not the slave robot is likely to tip over. A slave robot as described in Appendix 1 or Appendix 2. 【0064】 (Note 4) The system further includes a notification unit that notifies when the slave robot is about to fall over. A slave robot as described in any one of the following appendices, 1 to 3. 【0065】 (Note 5) After disconnecting the command system or reducing the influence from the master robot, the posture of the master robot and the posture of the slave robot are made the same. A slave robot as described in any one of the items in Appendix 1 to Appendix 4. 【0066】 (Note 6) A method for preventing a slave robot from tipping over, which changes its posture in response to a change in the posture of a master robot via a command system between the slave robot and the master robot, If the slave robot is about to fall over, the command system is disconnected or the influence from the master robot is reduced compared to when the slave robot is not about to fall over. Methods to prevent falls. 【0067】 (Note 7) Master robot and, A slave robot whose posture changes in response to changes in the posture of the master robot, via a command system between the slave robot and the master robot, A robotic system equipped with, If the slave robot is about to fall over, the command system is disconnected or the influence from the master robot is reduced compared to when the slave robot is not about to fall over. Robot system. [Explanation of symbols] 【0068】 100 Robot Systems 1030 Master Robot 2040 Slave Robot 10 Master Robot Arm 30 Master Robot Controllers 20 Slave Robot Arms 40 Slave Robot Controllers

Claims

[Claim 1] A slave robot whose posture changes in response to changes in the posture of the master robot via a command system between the slave robot and the master robot, A slave robot that, when it is about to fall over, disconnects the command system or reduces the influence from the master robot compared to when the slave robot is not about to fall over. [Claim 2] The master robot changes its posture in response to the change in posture of the slave robot. The slave robot according to claim 1. [Claim 3] Based on the inertial torque of the slave robot during its operation, it is determined whether or not the slave robot is likely to tip over. The slave robot according to claim 1. [Claim 4] The system further includes a notification unit that notifies when the slave robot is about to fall over. The slave robot according to claim 1. [Claim 5] After disconnecting the command system or reducing the influence from the master robot, the posture of the master robot and the posture of the slave robot are made the same. The slave robot according to claim 1. [Claim 6] A method for preventing a slave robot from tipping over, which changes its posture in response to a change in the posture of a master robot via a command system between the slave robot and the master robot, If the slave robot is about to fall over, the command system is disconnected or the influence from the master robot is reduced compared to when the slave robot is not about to fall over. Methods to prevent falls. [Claim 7] Master robot and, A slave robot whose posture changes in response to changes in the posture of the master robot, via a command system between the slave robot and the master robot, A robotic system equipped with, If the slave robot is about to fall over, the command system is disconnected or the influence from the master robot is reduced compared to when the slave robot is not about to fall over. Robot system.

Images