Robot safety devices and robotic systems

Abstract

This safety device for robots is applied to a robot that includes a control device for controlling robot speed, and includes a detection unit, a setting unit, and an output unit. The detection unit is capable of detecting an object that exists within a predetermined detection range, and detects the relative distance and the relative speed between the object within the detection range and the detection unit. The setting unit sets a speed limit value of the robot speed on the basis of a combination of the relative distance and the relative speed which have been detected by the detection unit. The output unit outputs, to the control device, the speed limit value which has been set by the setting unit.

Description

Technical Field

[0001] This specification discloses a safety device for a robot and a robot system.

Background Art

[0002] Conventionally, as a safety device for this type of robot, there has been proposed a device that measures the distance to an object existing in a search area by a detection device, generates a limit signal that limits the maximum speed of the robot according to the distance to the object, and transmits the generated limit signal to a robot controller (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an object is moving so as to approach a robot, the time until it reaches the robot changes depending on its moving speed. Therefore, in controlling the robot speed, it is desirable to take this into account. On the other hand, if in addition to the distance to the object, the moving speed of the object is also measured by a detection device and these measured values are transmitted to a robot controller, the interface between the safety device and the robot controller (control device) is complicated, leading to complication of the system.

[0005] The main object of the present disclosure is to improve safety while simplifying the system.

Means for Solving the Problems

[0006] The present disclosure has taken the following means to achieve the above main object.

[0007] The robot safety device of this disclosure is a robot safety device equipped with a control device for controlling the robot speed, comprising: a detection unit capable of detecting an object within a predetermined detection range, which detects the relative distance and relative speed between the object within the detection range and the detection unit; a setting unit that sets a speed limit value for the robot speed based on the combination of relative distance and relative speed detected by the detection unit; and an output unit that outputs the speed limit value set by the setting unit to the control device.

[0008] The robot safety device of this disclosure sets a speed limit for the robot's speed based on a combination of the relative distance and relative velocity between the object within the detection range and the detection unit, and outputs the set speed limit to the robot's control unit. Since the robot's control unit only needs to input the speed limit from the safety device, it can appropriately control the robot's speed based on the relative distance and relative velocity between the object and the detection unit without complicating the interface between the control unit and the safety device. As a result, safety can be improved while simplifying the system.

[0009] The gist of the robot system of this disclosure is that it comprises a robot body, a robot control device for controlling the robot speed of the robot body, a detection unit capable of detecting objects within a predetermined detection range and detecting the relative distance and relative speed between the objects within the detection range and the detection unit, a setting unit for setting a speed limit value for the robot speed based on the combination of relative distance and relative speed detected by the detection unit, and an output unit for outputting the speed limit value set by the setting unit to the robot control device.

[0010] The robotic system of this disclosure is equipped with the safety device of this disclosure, and therefore can achieve the same effect as the safety device of this disclosure, namely, the effect of simplifying the system while further improving safety. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of the robot system according to this embodiment. [Figure 2] This is a block diagram showing the electrical connection relationships between the robot body, the robot control device, and the safety device. [Figure 3] This flowchart shows an example of information output processing performed by the control unit of a safety device. [Figure 4] This is an explanatory diagram showing the relationship between relative distance, relative velocity, and robot velocity number. [Figure 5] This is an explanatory diagram showing the relationship between robot speed number, speed override, and output information. [Figure 6] This is an explanatory diagram showing the relationship between the relative distance between the safety device and the interfering object, and the velocity override. [Figure 7] This diagram illustrates the relationship between the movement speed of an interfering object, the time until collision with the robot body, and speed override. [Figure 8] This diagram illustrates the relationship between the movement speed of an interfering object, the time until collision with the robot body, and speed override. [Figure 9] This diagram illustrates the relationship between the movement speed of an interfering object, the time until collision with the robot body, and speed override. [Figure 10] This is a flowchart showing information output processing according to another embodiment. [Figure 11] This is an explanatory diagram showing the relationship between relative distance and output information. [Figure 12] This is a schematic diagram of a robot system according to another embodiment. [Modes for carrying out the invention]

[0012] Next, the forms for implementing this disclosure will be described with reference to the drawings.

[0013] FIG. 1 is a schematic configuration diagram of the robot system 1 of the present embodiment. FIG. 2 is a block diagram showing the electrical connection relationship among the robot body 10, the robot control device 20, and the safety device 30. As shown in the figure, the robot system 1 of the present embodiment includes a robot body 10, a robot control device 20 that controls the operation of the robot body 10, and a robot safety device 30 that can detect interfering objects around the robot body 10.

[0014] The robot body 10 is a work robot that performs a predetermined operation. For example, it can be a machining robot that processes a workpiece with a tool, a transfer robot that grips a workpiece with a chuck and transfers it to another position, an assembly robot that grips a workpiece with a chuck and assembles it to an object, and the like.

[0015] The robot body 10 has a base 11 and an articulated arm 12 installed on the base 11. The articulated arm 12 has a plurality of arms connected in series to the base 11 via joint axes. On each joint axis, a servo motor 15 that drives the corresponding joint axis and an encoder 16 (rotary encoder) that detects the rotation angle of the corresponding servo motor 15 are arranged. Further, the robot body 10 also includes an amplifier unit 17 that applies a driving current to each servo motor 15.

[0016] The robot control device 20 includes a control unit 21 configured as a microprocessor including a CPU, a ROM, and a RAM, and an I / O port 22 for exchanging signals with the control unit 31 of the safety device 30. Further, the robot control device 20 outputs a control signal to the amplifier unit 17 of the robot body 10 and inputs a detection signal from the encoder 16.

[0017] The control unit 21 of the robot control device 20 controls the operation of the robot body 10 as follows. That is, first, the control unit 21 sets the target angles of the respective joint axes of the articulated arm 12 by inverse kinematics from the target position and target posture of the end. Subsequently, the control unit 21 acquires the current angles of the respective joint axes from the corresponding encoders 16, and sets the speed command values of the joint axes by feedback calculation (for example, proportional integral calculation or proportional integral derivative calculation) based on the difference between the target angle and the current angle for each joint axis. Next, the control unit 21 sets a target speed with the speed limited by multiplying the speed command value by a speed override, which will be described later, and is defined within the range of value 0 (0%) or more and value 1 (100%) or less. For example, if the speed override is value 1 (100%), the target speed will be the same value as the speed command value. That is, the robot speed is not limited. Also, if the speed override is value 0.5 (50%), the target speed will be half the speed of the speed command value. Further, if the speed override is value 0 (0%), the target speed will be value 0 regardless of the speed command value. That is, the robot body 10 stops operating. Subsequently, the control unit 21 calculates the current speed from the current angles of the joint axes acquired from the encoders 16, and sets the torque command value to be output from the servo motor 15 by feedback calculation (for example, proportional integral calculation or proportional integral derivative calculation) based on the difference between the calculated current speed and the target speed. Then, the control unit 21 outputs a control signal to the corresponding amplifier unit 17 so that the torque corresponding to the set torque command is output from the servo motor 15.

[0018] In this embodiment, the robot safety device 30 is attached to the end of the articulated arm 12. The safety device 30 includes a control unit 31 configured as a microprocessor including a CPU, a ROM, and a RAM, a sensor unit 32 for monitoring the surroundings, and an I / O port 33 for exchanging signals with the control unit 21.

[0019] In this embodiment, the sensor unit 32 is configured as an FMCW (Frequency Modulation Continuous Wave) radar sensor. The sensor unit 32 includes a transmitting antenna that transmits a transmit chirp, a receiving antenna that receives reflected waves from an object as a receive chirp, a mixer that mixes the transmit chirp and the receive chirp to generate an intermediate frequency signal (IF signal), and a processing unit that processes the IF signal to detect the relative distance L to the object and the relative velocity V with respect to the object. The transmitting antenna is modulated so that its frequency changes over time, and transmits multiple transmit chirps, each spaced at a certain interval, as one frame. The processing unit includes an A / D converter that performs A / D conversion on the IF signal generated by the mixer, and a DSP that performs Fourier transform (FFT) processing on the A / D converted IF signal. The DSP can calculate the relative distance L to the object based on the peak frequency by performing FFT processing (distance FFT processing) on ​​the IF signal on a chirp-by-chirp basis to obtain a frequency spectrum. Furthermore, the DSP can calculate the relative velocity V with respect to an object based on the peak angular frequency by performing an FFT (velocity FFT) on the data after distance FFT processing on a frame-by-frame basis to obtain the peak angular frequency.

[0020] Next, the operation of the safety device 30 of this embodiment will be described. Figure 3 is a flowchart showing an example of information output processing performed by the control unit 31 (CPU) of the safety device 30. In the information output processing, the control unit 31 first obtains the relative distance L and relative velocity V between the sensor unit 32 and the interfering object from the sensor unit 32 (S100). Subsequently, the control unit 31 sets the robot speed number N corresponding to the speed override based on the acquired combination of relative distance L and relative velocity V (S110). The setting of the robot speed number N is done by pre-determining the relationship between the relative distance L, relative velocity V and robot speed number N and storing it as a table, and then deriving the corresponding robot speed number N from the table when the relative distance L and relative velocity V are given. The relationship between the relative distance L, relative velocity V and robot speed number N is shown in Figure 4. As shown in the figure, the robot speed number N is set such that the speed override decreases as the relative distance L from the sensor unit 32 to the interfering object decreases, and the speed override decreases as the relative speed V between the sensor unit 32 and the interfering object in the direction approaching the robot body 10 increases. As a result, the robot speed is greatly restricted as the relative distance L from the sensor unit 32 to the interfering object decreases, and as the relative speed V between the sensor unit 32 and the interfering object in the direction approaching the robot body 10 increases.

[0021] When the control unit 31 sets a robot speed number N, it converts the set robot speed number N into predetermined bit output information (S120). Here, the output information represents the speed override (for example, five speed limit values ​​of 0%, 25%, 50%, 75%, and 100%) using predetermined bit (for example, 4 bits) of information. The conversion of the output information is performed by pre-determining the relationship between the robot speed number N and the output information and storing it as a table, and then deriving the corresponding output information from the table when the robot speed number N is given. Figure 5 shows the relationship between the robot speed number, the speed override, and the output information. The relationship between the combination of relative distance L and relative speed V and the speed override can be changed as appropriate by connecting a computer to the safety device 30 and operating the computer. Then, the control unit 31 transmits the output information to the robot control device 20 via the I / O port 33 (S130) and terminates the information output processing. The robot control device 20 receives output information from the control unit 31 of the safety device 30 as a speed override via the I / O port 22, and controls the servo motor 15 by setting a target speed that is limited according to the speed override by multiplying the received speed override by the speed command value.

[0022] Figure 6 is an explanatory diagram showing the relationship between the relative distance between the safety device 30 (sensor unit 32) and the interfering object, and the speed override. As shown in the figure, if there is no interfering object within the detection range of the sensor unit 32 (relative distance between the sensor unit 32 and the interfering object up to 2000 mm), that is, if the sensor unit 32 does not detect an interfering object, the speed override is set to 100%. In other words, the robot speed is not limited. On the other hand, if there is an interfering object within the detection range of the sensor unit 32, that is, if the sensor unit 32 detects an interfering object, the speed override decreases as the interfering object approaches the sensor unit 32. Furthermore, if the interfering object is moving, the speed override decreases as the relative speed between the sensor unit 32 and the interfering object increases in the direction approaching the sensor unit 32. In other words, the robot speed is more restricted as the interfering object approaches the robot body 10, and as the movement speed of the interfering object in the direction approaching the robot body 10 increases. In this embodiment, as shown in Figures 7 and 8, when an interfering object (worker) is located within the detection range of the sensor unit 32 and is moving toward the robot body 10 (sensor unit 32), the speed override is set to the same value regardless of the position of the interfering object within the detection range, provided that the time until collision with the robot body 10 (sensor unit 32) is the same. Furthermore, as shown in Figure 9, even when an interfering object is moving toward the robot body 10 (sensor unit 32), if the interfering object's movement speed is slow and there is ample time before collision with the robot body 10 (sensor unit 32), the speed override is set to 100% so that the robot speed is not restricted. This suppresses unnecessary speed restrictions on the robot body 10, while more reliably stopping the robot body 10 when a worker approaches it, thereby ensuring worker safety.

[0023] Here, the correspondence between the main elements of the embodiment and the main elements of the present disclosure as described in the claims will be explained. Specifically, the sensor unit 32 of this embodiment corresponds to the detection unit of the present disclosure, the control unit 31 that executes the information output processing S110 and S120 corresponds to the setting unit, and the control unit 31 that executes the information output processing S130 and the I / O port 33 correspond to the output unit. Also, the robot body 10 corresponds to the robot body, and the robot control device 20 corresponds to the robot control device.

[0024] It goes without saying that this disclosure is not limited in any way to the embodiments described above, and can be implemented in various forms as long as they fall within the technical scope of this disclosure.

[0025] For example, in the embodiment described above, the speed override is transmitted to the robot control device 20 by outputting predetermined bit output information to the robot control device 20 via the I / O port 33. However, the safety device 30 may be capable of switching between output information corresponding to the speed override and output information corresponding to the relative distance L and transmitting them to the robot control device 20 via the I / O port 33. Figure 10 is a flowchart of the information output processing according to another embodiment. The control unit 31 of the safety device 30 determines whether the processing mode is mode A or mode B (S200). The processing mode is set in advance by the operator inputting an operation using the input device. When the control unit 31 determines that the processing mode is mode A, it obtains the relative distance L and relative velocity V between the sensor unit 32 and the interfering object, similar to S100 to S130 of the information output processing in Figure 3, sets a robot speed number based on the combination of relative distance L and relative velocity V, converts the robot speed number into output information, outputs the output information to the robot control device 20 via the I / O port 33 (S210 to S240), and terminates the information output processing. On the other hand, when the control unit 31 determines that the processing mode is mode B, it acquires the relative distance L between the sensor unit 32 and the interfering object (S250), converts the acquired relative distance L into output information (S260), outputs the output information to the robot control device 20 via the I / O port 33 (S240), and terminates the information output processing. The relationship between the relative speed L and the output information is shown in Figure 11. This makes it possible to accommodate both robot specifications that control the robot speed by inputting a speed override and robot specifications that control the robot speed based on the relative distance between the sensor unit 32 and the interfering object by inputting the relative distance.

[0026] In the embodiment described above, the safety device 30 is attached to the end portion (tip portion) of the articulated arm 12 of the robot body 10, but it may also be attached to the base 11 of the robot body 10. Furthermore, although the safety device 30 is provided on a stationary robot, it may also be provided on a self-propelled robot. The self-propelled robot may be a transport robot in addition to the articulated arm robot described above. For example, as shown in Figure 12, in a mounting line 100 having feeder stands arranged in the direction of transport of a substrate and each having a feeder 102 that can be attached and detached, and equipped with a plurality of component mounting machines 101 that pick up components from the feeder 102 and mount them on a substrate, there may be an automatic exchange robot 110 that moves along the mounting line 100 and exchanges the feeder 102 for each component mounting machine 101. The safety device 30 is provided on the automatic exchange robot 110, and when an interfering object is detected within the detection range, it outputs output information to the automatic exchange robot 110 according to the combination of the relative distance L and relative velocity V with respect to the interfering object. The automatic exchange robot 110 travels at a limited travel speed corresponding to the speed override by multiplying the speed command value by the speed override based on the input output information.

[0027] As described above, the robot safety device of this disclosure sets a speed limit for the robot's speed based on a combination of the relative distance and relative velocity between the object within the detection range and the detection unit, and outputs the set speed limit to the robot's control unit. Since the robot's control unit only needs to input the speed limit from the safety device, it is possible to appropriately control the robot's speed based on the relative distance and relative velocity between the object and the detection unit without complicating the interface between the control unit and the safety device. As a result, safety can be further improved while simplifying the system.

[0028] In the robot safety device of this disclosure, the output unit outputs information of a predetermined number of bits as the speed limit value to the control device via an input / output port, and the setting unit may select and set one of a plurality of pieces of information to which different speed limit values ​​are assigned based on the combination of relative distance and relative speed detected by the detection unit. This reduces the number of input / output ports and simplifies the device compared to a system that converts the relative distance and relative speed detected by the detection unit into information of a predetermined number of bits and outputs it to the robot's control device.

[0029] Furthermore, in the robot safety device of this disclosure, the speed limit value may be a speed override value multiplied by the robot's speed command value. In this way, the robot's speed can be limited simply by multiplying by the speed override value.

[0030] Furthermore, in the robot safety device of this disclosure, the output unit may have a first mode in which it outputs a speed limit value set by the setting unit to the control device, and a second mode in which it outputs the relative distance to the object detected by the detection unit to the control device. This makes it possible to accommodate both a robot specification in which the robot speed is controlled by inputting a speed limit value, and a robot specification in which the robot speed is controlled based on the relative distance between the detection unit and the object.

[0031] Furthermore, this disclosure is not limited to the form of a safety device for a robot, but may also be in the form of a robot system comprising a robot body, a control device, and a safety device. In this case, the robot body may be an arm robot equipped with an arm. Alternatively, the robot body may be an automatic exchange robot that moves along a predetermined travel line and exchanges feeders for each component mounting machine in a mounting line equipped with multiple component mounting machines that are arranged in the direction of transport of the substrate and each capable of picking up components from a feeder and mounting them on the substrate. [Industrial applicability]

[0032] This disclosure can be used in industries such as the manufacturing of robots and safety devices. [Explanation of Symbols]

[0033] 1 Robot system, 10 Robot body, 11 Base, 12 Articulated arm, 15 Servo motor, 16 Encoder, 17 Amplifier unit, 20 Robot control device, 21 Control unit, 22 I / O port, 30 Safety device, 31 Control unit, 32 Sensor unit, 33 I / O port, 100 Mounting line, 101 Component mounting machine, 102 Feeder, 110 Automatic exchange robot.

Claims

1. A safety device for a robot equipped with a control device for controlling the robot's speed, A detection unit capable of detecting an object within a predetermined detection range, comprising a detection unit that detects the relative distance and relative velocity between the object within the detection range and the detection unit, A setting unit sets a predetermined speed limit value for the robot speed based on the combination of relative distance and relative speed detected by the detection unit, An output unit that outputs the speed limit value set by the setting unit to the control device, Equipped with, The setting unit is a safety device for a robot that sets the speed limit value such that the shorter the time it takes for an object within the detection range to collide with the robot, the greater the robot speed limit, and the same limit for the robot speed for combinations of relative distance and relative speed where the time until collision is the same.

2. A safety device for a robot according to claim 1, The output unit outputs predetermined bit information to the control device as the speed limit value via the input / output port. The setting unit selects and sets one of the multiple pieces of information to which different speed limit values ​​are assigned based on the combination of relative distance and relative speed detected by the detection unit. Safety devices for robots.

3. A safety device for a robot according to claim 1 or 2, The speed limit value is a speed override value that is multiplied by the speed command value of the robot. Safety devices for robots.

4. A safety device for a robot according to any one of claims 1 to 3, The output unit has a first mode in which it outputs a speed limit value set by the setting unit to the control device, and a second mode in which it outputs the relative distance to the object detected by the detection unit to the control device. Safety devices for robots.

5. The robot body and A robot control device that controls the robot speed of the robot body, A safety device comprising: a detection unit capable of detecting an object within a predetermined detection range, which detects the relative distance and relative velocity between the object within the detection range and the detection unit; a setting unit that sets a predetermined speed limit value for the robot speed based on the combination of relative distance and relative velocity detected by the detection unit; and an output unit that outputs the speed limit value set by the setting unit to the robot control device. Equipped with, The setting unit sets the speed limit value such that the robot speed is restricted more as the time until an object within the detection range collides with the robot body becomes shorter, and the speed limit is the same for combinations of relative distance and relative speed where the time until collision is the same.

6. A robot system according to claim 5, The robot body is an arm robot equipped with an arm. Robot system.

7. A robot system according to claim 5, The robot body is an automatic exchange robot that moves along a predetermined travel line and exchanges feeders for each component mounting machine in an assembly line equipped with multiple component mounting machines that are arranged in the direction of transport of the circuit board and each capable of picking up components from a feeder and mounting them on the circuit board. Robot system.

Images