Sensor device and control system provided with the same

Abstract

To provide a sensor device that can detect approach and contact of an object to be detected, with a simple configuration.SOLUTION: A sensor device 10 is provided with: one sensor CS for detecting an object DO to be detected; two output lines L1 and L2 connected to the sensor CS; and first and second detection / conversion circuits 11 and 12 which are connected to the output lines L1 and L2, respectively, which each detect analog output signals from the sensor CS, on which thresholds different from each other are set and which each convert output the analog output signals from the sensor CS to digital signals to output the signals, on the basis of the thresholds.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sensor device for detecting the proximity and contact of an object to be detected, and a control system including the same. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2006-43792 discloses a robot with a collision prevention function that prevents collision with humans or obstacles. The robot is provided with an arm (7) and includes a distance sensor (8) that detects the distance to a nearby human or object, a proximity check unit (3) that checks whether a nearby human or object is approaching based on the detection signal of the distance sensor (8), and an arm control unit (5) that controls the arm (7) to maintain a distance from the human or object at or above a certain value when the proximity check unit (3) determines that the arm (7) has come close to a nearby human or object (see paragraphs

[0004] ,

[0007] ,

[0008] , and Figures 1 to 3 of the publication).

[0003] According to the above publication, by maintaining a distance between the arm (7) and nearby people or objects at a certain value or more, it is possible to prevent collisions between the arm (7) and nearby people or objects (see paragraphs

[0005] ,

[0007] , and

[0008] of the same publication).

[0004] However, in the above-mentioned conventional configuration, not only does the distance sensor (8) constantly detect the distance to nearby people or objects, but when a person or object approaches, the arm (7) must be controlled by the arm control unit (5) so that the distance between the arm (7) and the person or object is always maintained at a certain value or more, which requires complicated real-time control (see paragraphs

[0007] ,

[0008] and Figure 4 of the same publication).

[0005] Meanwhile, Japanese Patent Application Laid-Open No. 2018-149673 discloses a non-contact sensor device that detects the approach of a person or the like to the arm of a robot. The sensor device (1) has capacitance-type proximity switches (4, 6) and is provided so as to be wrapable around the arm (101) of a robot (100) (see paragraphs

[0018] ,

[0021] ,

[0025] and Figures 1 to 5 of the publication).

[0006] When a person or the like enters the sensor detection range of the sensor device (1), the sensor device (1) outputs a detection signal, which is input to the control box (50), causing the arm (101) to make an emergency stop or operate at a reduced speed (see paragraph

[0030] and Figure 8 of the same publication). Summary of the Invention [Problem to be solved by the invention]

[0007] Generally, a capacitance sensor detects or does not detect a target by utilizing the change (i.e., increase or decrease) in the capacitance of a detection electrode when the target, such as a person, enters or leaves a detection area. The analog output of the capacitance sensor is converted by a sensor controller into an ON / OFF digital signal depending on whether or not the output exceeds a preset threshold, and is then output.

[0008] When such a capacitance sensor is installed on a robot arm, if an ON digital signal is output from the sensor controller of the capacitance sensor, the robot controller determines that a worker or other person is approaching the robot arm and is in a dangerous situation, and slows down or stops the robot arm.

[0009] Incidentally, if a sensor controller for a capacitance type sensor is capable of setting two or more thresholds and performing threshold processing according to each threshold, it is conceivable that the sensor controller could output a proximity detection signal when the robot arm is in proximity to the worker and a contact detection signal when the robot arm has come into contact with the worker, and control the robot controller to slow down or stop the robot arm in accordance with these signals.

[0010] However, in this case, the sensor controller outputs an ON / OFF digital signal for each set threshold value, so the robot controller must first control the drive of the robot arm based on the digital signal output from the sensor controller, and then separately control the drive of the robot arm based on another digital signal output from the sensor controller. This creates a problem of complex drive control programs for the robot arm. Furthermore, in this case, if you try to check whether all the signals output from the sensor controller are normal, even more complicated processing is required.

[0011] The present invention has been made in view of the above-described conventional circumstances, and aims to solve the problem of providing a sensor device that can detect the proximity and contact of a detection object with a simple configuration. The present invention also aims to provide a control system that can detect the proximity and contact of a detection object with a simple configuration and can decelerate / stop a moving part of a machine when the detection object is detected. [Means for solving the problem]

[0012] The sensor device of the present invention comprises one sensor for detecting an object to be detected, at least two output lines provided on the sensor, and detection / conversion units connected to each output line, which detect analog output signals of the sensor, have different thresholds set, and convert the analog output signals of the sensor into digital signals based on the thresholds and output the digital signals.

[0013] According to the present invention, when a sensor detects an object to be detected, the sensor outputs a detection signal to each output line. Then, in the detection / conversion units connected to each output line, the analog output signals of the sensors are detected, threshold-processed based on the thresholds set for each, and digital signals are output. This allows the proximity and contact of the object to be detected.

[0014] In this case, different thresholds are set in each detection / conversion unit, and different threshold processing is performed for each, with only one output being output from each output line. Therefore, the detection output that detects the proximity of the detection object and the detection output that detects contact with the detection object are output from different output lines. This allows for a one-output, one-control configuration, and simplifies the program configuration, making it possible to detect the proximity and contact of the detection object with a simple configuration. Moreover, in this case, since there are two or more output systems, safety-related functions can be made redundant, improving safety.

[0015] In the present invention, one of the thresholds is for detecting the proximity of the detection object, and the other of the thresholds is for detecting the contact of the detection object.

[0016] The control system according to the present invention is equipped with the sensor device described above, and the detection and conversion unit is composed of a first detection and conversion unit that outputs a first digital output signal based on a first threshold value, and a second detection and conversion unit that outputs a second digital output signal based on a second threshold value that is greater than the first threshold value, and controls the moving part of the machine to slow down based on the first digital output signal from the first detection and conversion unit, and to stop the moving part of the machine based on the second digital output signal from the second detection and conversion unit.

[0017] According to the present invention, the moving part of the machine is controlled to slow down or stop based on the first and second digital output signals from the first and second detection / conversion parts, which not only makes it possible to detect the proximity and contact of the detection object with a simple configuration, but also ensures the safety of the worker while suppressing a decrease in productivity.

[0018] A control system according to the present invention includes the sensor device described above and a stop switch for stopping a moving part of a machine. The stop switch has a stop button that can be manually depressed from a pre-depression position to a post-depression position, and an actuation unit that can depress the stop button from the pre-depression position to the post-depression position. The detection and conversion unit is composed of a first detection and conversion unit that outputs a first digital output signal based on a first threshold value, and a second detection and conversion unit that outputs a second digital output signal based on a second threshold value that is greater than the first threshold value. The control system decelerates the moving part of the machine based on the first digital output signal from the first detection and conversion unit, and activates the actuation unit of the stop switch based on the second digital output signal from the second detection and conversion unit, thereby controlling the machine so that the stop button is depressed to stop the moving part of the machine.

[0019] According to the present invention, the moving part of the machine decelerates based on a first digital output signal from a first detection / conversion unit, and the operating part operates based on a second digital output signal from a second detection / conversion unit. When the operating part operates, the stop button of the stop switch is pressed from a pre-pressing position to a post-pressing position, stopping the moving part of the machine. This not only makes it possible to detect the proximity and contact of the detection object with a simple configuration, but also ensures the safety of the worker while suppressing a decrease in productivity. Moreover, in this case, when the detection object comes into contact with the moving part of the machine, for example, the operating part can immediately stop the moving part of the machine, further improving safety.

[0020] In the present invention, the stop button can be manually returned from the position after being pressed to the position before being pressed.

[0021] In the present invention, the pressed state of the stop button after it has been pressed by the operation of the operating portion is maintained unless a manual return operation is performed.

[0022] According to the present invention, by making the manual reset operation of the stop button a condition for restarting the moving part after it has been stopped by the operating part, it is possible to prevent the moving part from being restarted unintentionally by the operator.

[0023] In the present invention, the pressed state after the stop button is pressed by the operation of the operating unit is maintained as long as all the digital output signals of the detection / conversion units do not become low.

[0024] According to the present invention, by setting the condition for restarting the moving part after it has been stopped by the operating part as being that all digital output signals of each detection / conversion part are Low (i.e., that no detection target such as a worker or object is in proximity or contact), it is possible to prevent the moving part from restarting when a worker or other person is located around the moving part.

[0025] In the present invention, the actuation unit is composed of an electromagnetic solenoid, and the supply of current to the electromagnetic solenoid is maintained unless all the digital output signals of the detection / conversion units are low.

[0026] According to the present invention, by setting the condition for stopping the supply of current to the electromagnetic solenoid as all digital output signals of each detection / conversion unit being Low (i.e., the detection target such as a worker or object is not in proximity or contact), it is possible to prevent the supply of current to the electromagnetic solenoid from being stopped when a worker or object is located around the moving part, and to prevent the stop button from being inadvertently reset.

[0027] A control system according to the present invention includes the sensor device described above and a stop switch for stopping a moving part of a machine. The stop switch includes a stop button that can be manually depressed from a pre-depression position to a post-depression position, and an actuating unit that can depress the stop button from the pre-depression position to the post-depression position. The detecting / converting unit includes a first detecting / converting unit that outputs a first digital output signal based on a first threshold value, and a second detecting / converting unit that outputs a second digital output signal based on a second threshold value that is greater than the first threshold value. After stopping the moving part of the machine based on the first digital output signal from the first detecting / converting unit, if the digital output signal from the first detecting / converting unit goes low, the moving part of the machine is allowed to restart, and the actuating unit of the stop switch is actuated based on the second digital output signal from the second detecting / converting unit. After the stop button is depressed to stop the moving part of the machine, the actuating unit is controlled to maintain the depressed state of the stop button even if the digital output signal from the second detecting / converting unit goes low.

[0028] According to the present invention, the moving part of the machine is temporarily stopped based on the first digital output signal from the first detection and conversion unit, and then when the digital output signal of the first detection and conversion unit goes low, the moving part of the machine is allowed to restart. Also, after the operating unit of the stop switch is operated based on the second digital output signal from the second detection and conversion unit and the stop button is pressed to stop the moving part of the machine, the pressed state of the stop button after being pressed due to the operation of the operating unit is maintained even if the digital output signal of the second detection and conversion unit goes low.

[0029] This not only makes it possible to detect the proximity and contact of the detection object with a simple configuration, but also, when the proximity of the detection object is detected, the moving parts of the machine are stopped temporarily and can be restarted as soon as it is confirmed that the digital output signal for proximity detection has gone low, thereby ensuring the safety of the worker while suppressing a decline in productivity. Also, when contact with the detection object is detected, the moving parts of the machine are immediately stopped by the operating unit, and even after that, even if the digital output signal for contact detection goes low, the pressed state of the stop button after being pressed by the operating unit is maintained, thereby further improving safety and ensuring the safety of the worker.

[0030] In the present invention, the stop switch is an emergency stop switch.

[0031] In the present invention, the machine is a collaborative robot or an automated guided vehicle that works in collaboration with a worker. [Effects of the Invention]

[0032] As described above, according to the present invention, it is possible to detect the proximity and contact of a detection target with a simple configuration. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a front view of a robot having a sensor according to an embodiment of the present invention. [Figure 2] 1 is a schematic block diagram of a control system including a sensor device according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a detailed view of a portion of the control system (FIG. 2). [Figure 4] FIG. 10 is a schematic block diagram of a control system including a sensor device according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a detailed view of a portion of the control system (FIG. 4). [Figure 6] FIG. 5 is a schematic vertical cross-sectional view of a stop switch provided in the sensor device (FIG. 4), showing the stop switch in a non-operated state. [Figure 7]This shows the state when the stop switch (FIG. 6) is operated (manually or by pressing with the operating part). [Figure 8] FIG. 10 is a schematic block diagram of a control system including a sensor device according to a fourth embodiment of the present invention. [Figure 9] FIG. 10 is a schematic block diagram of a control system including a sensor device according to a fifth embodiment of the present invention. [Figure 10] This is an example of a graph showing the relationship between the distance between a transmitter carried by a worker and a receiver installed on a robot arm in the control system (Figure 9), with the horizontal axis representing the distance and the vertical axis representing the strength of the signal received by the receiver. [Figure 11] FIG. 10 is a schematic block diagram of a control system including a sensor device according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. 1 is a diagram illustrating a sensor according to an embodiment of the present invention. Here, a capacitive proximity sensor is used as an example of the sensor. Furthermore, a vertical articulated robot, particularly the arm of a collaborative robot that works in collaboration with a worker, is used as an example of the moving part of the machine on which the sensor is installed.

[0035] FIG. 1 shows a state in which a sensor (capacitive proximity sensor) CS according to this embodiment is wrapped around an arm of a robot R. The robot R has three arms Ra1, Ra2, and Ra3, and the sensor CS is provided on one of these three arms, for example, arm Ra1. The sensor CS can be in a wrapped state (FIG. 1) in which it is wrapped in a ring shape in the circumferential direction around the outer surface of arm Ra1, or in an unfolded state (not shown) in which it is unfolded on a plane. The sensor CS is used to detect the proximity and contact of a detection target, such as a person P such as a worker or an object (not shown), with the robot R.

[0036] [First Example] FIG. 2 shows a schematic block diagram of a control system equipped with a sensor device according to a first embodiment of the present invention. As shown in the figure, the sensor (capacitive proximity sensor) CS has a sensor electrode CS1 for detecting the proximity and contact of a detection target DO, and a ground electrode CS2 that is positioned opposite the sensor electrode CS1 at a predetermined distance and is grounded. In the figure, the symbol CP represents the capacitance between the sensor electrode CS1 and the detection target DO. The capacitance CP changes depending on the proximity state of the detection target DO (i.e., how close the detection target DO is to the sensor electrode CS1), becoming larger as the detection target DO approaches and becoming smaller as the detection target DO moves away.

[0037] Two output lines L1 and L2 are connected to the sensor electrode CS1. The output line L1 is connected to a first detection and conversion circuit (first detection and conversion unit) 11, and the output line L2 is connected to a second detection and conversion circuit (second detection and conversion unit) 12. In addition, two ground lines G1 and G2 are connected to the ground electrode CS2. The ground line G1 is connected to the first detection and conversion circuit 11, and the ground line G2 is connected to the second detection and conversion circuit 12.

[0038] The first detection / conversion circuit 11 detects the analog output signal of the sensor CS and converts it into a digital signal based on a preset first threshold value for output. Similarly, the second detection / conversion circuit 12 detects the analog output signal of the sensor CS and converts it into a digital signal based on a preset second threshold value that is different from the first threshold value of the first detection / conversion circuit 11 for output.

[0039] In this example, the second threshold is set to a value greater than the first threshold. The first threshold is for detecting the proximity of the detection object DO, and the second threshold is for detecting contact of the detection object DO. The first detection and conversion circuit 11 outputs an ON signal based on a change in capacitance caused by the proximity of the detection object DO. Similarly, the second detection and conversion circuit 12 outputs an ON signal based on a change in capacitance caused by contact of the detection object DO. The sensor CS, first detection and conversion circuit 11, and second detection and conversion circuit 12 described above constitute a sensor device 10 according to the present invention.

[0040] The outputs of the first detection and conversion circuit 11 and the second detection and conversion circuit 12 are input to a control unit 13. The control unit 13 is connected to the arms Ra1, Ra2, and Ra3 of the robot R (FIG. 1). Each arm Ra1, Ra2, and Ra3 can be driven by a driving means such as a servo motor (not shown). As a result, the arms Ra1, Ra2, and Ra3 of the robot R are driven and controlled based on the outputs of the first detection and conversion circuit 11 and the second detection and conversion circuit 12. The sensor device 10 and control unit 13 described above constitute a control system 1 according to the present invention.

[0041] When the detection object DO approaches, the arms Ra1, Ra2, Ra3 of the robot R are controlled to, for example, decelerate, and when the detection object DO comes into contact, the arms Ra1, Ra2, Ra3 of the robot R are controlled to, for example, stop.

[0042] The first detection and conversion circuit 11 and the second detection and conversion circuit 12 are provided with a first display unit 14 and a second display unit 15, respectively. These display units 14, 15 are made visible from outside the sensor CS, for example by being illuminated. The first display unit 14 is for displaying that the first detection and conversion circuit 11 is performing detection and digital output, and similarly, the second display unit 15 is for displaying that the second detection and conversion circuit 12 is performing detection and digital output.

[0043] FIG. 3 is a detailed diagram of a portion of the control system 1. As shown in the figure, VCC1 and SOUT1 of the sensor CS are connected to a first detection and conversion circuit 11, and the output of the first detection and conversion circuit 11 is connected to a robot controller 13A of the control unit 13. A power supply 13B of the control unit 13 is connected to the first detection and conversion circuit 11 and also to GND1 of the sensor CS. Similarly, VCC2 and SOUT2 of the sensor CS are connected to a second detection and conversion circuit 12, and the output of the second detection and conversion circuit 12 is connected to the robot controller 13A of the control unit 13. The power supply 13B of the control unit 13 is connected to the second detection and conversion circuit 12 and also to GND2 of the sensor CS. In addition, the arms Ra1, Ra2, and Ra3 of the robot R are connected to the robot controller 13A of the control unit 13.

[0044] Next, the effects of this embodiment will be described. When the detection target DO approaches the robot R, the detection target DO is detected by the sensor CS. Then, the detection output from the sensor CS is output to the output lines L1 and L2 and input to the first and second detection and conversion circuits 11 and 12 for detection. Here, the first and second detection and conversion circuits 11 and 12 are respectively set with first and second thresholds for threshold processing of the analog output signal from the sensor CS, and the first threshold is smaller than the second threshold.

[0045] Now, when the detection target DO is located at a position away from the sensor CS and the detection output of the sensor CS is smaller than the first threshold, the first detection / conversion circuit 11 does not output a high digital output signal, and similarly the second detection / conversion circuit 12 does not output a high digital output signal, and all digital output signals remain low. At this time, the arms Ra1, Ra2, and Ra3 of the robot R are not decelerated (nor stopped) and are operated normally according to the control program. Also, at this time, the displays 14 and 15 are turned off.

[0046] Next, when the detection target DO is located close to the sensor CS and the detection output of the sensor CS is greater than the first threshold and less than the second threshold, a high digital output signal (first digital output signal) is output from the first detection and conversion circuit 11. This detects that the detection target DO is located close to the sensor CS (i.e., in a proximity state). At this time, the first display unit 14 illuminates, for example, green. Meanwhile, the second detection and conversion circuit 12 does not output a high digital output signal and remains low. At this time, the second display unit 15 remains off. The high digital output signal (first digital output signal) output from the first detection and conversion circuit 11 is input to the robot controller 13A of the control unit 13. As a result, the arms Ra1, Ra2, and Ra3 of the robot R are driven and controlled to transition to a deceleration operation mode.

[0047] Next, when the detection target DO is in a position closer to (or in contact with) the sensor CS and the detection output of the sensor CS is greater than the second threshold, a high digital output signal (second digital output signal) is output from the second detection and conversion circuit 12. This detects that the detection target DO is in a position closer to (i.e., in proximity to) or in contact with (i.e., in contact with) the sensor CS. At this time, the second display unit 15 illuminates, for example, in red, and the first display unit 14 is turned off. The high digital output signal (second digital output signal) output from the second detection and conversion circuit 12 is input to the robot controller 13A of the control unit 13. As a result, the arms Ra1, Ra2, and Ra3 of the robot R are driven and controlled to stop.

[0048] At this time, since the detection output of the sensor CS is also greater than the first threshold value, a high digital output signal may also be output from the first detection and conversion circuit 11, but in that case, when high digital output signals are output from both the first and second detection and conversion circuits 11, 12, the robot controller 13A will process the high digital output signal from the second detection and conversion circuit 12 with priority (for example, perform override control).As a result, based on the high digital output signal (second digital output signal) from the second detection and conversion circuit 12, the arms Ra1, Ra2, and Ra3 of the robot R are driven and controlled to stop.

[0049] Furthermore, when the detection output of the sensor CS becomes larger than the second threshold, if a high digital output signal (first digital output signal) has already been output from the first detection and conversion circuit 11, the threshold processing function of the first detection and conversion circuit 11 may be temporarily disabled so that a high digital output signal is not output from the first detection and conversion circuit 11 and a high digital output signal (second digital output signal) is output only from the second detection and conversion circuit 12. Even in this case, the arms Ra1, Ra2, and Ra3 of the robot R are driven and controlled to stop based on the high digital output signal (second digital output signal) from the second detection and conversion circuit 12.

[0050] As described above, according to this embodiment, different thresholds can be set in the first and second detection / conversion circuits 11 and 12, and different threshold processes are performed for each. Only one output is output from each of the output lines L1 and L2. Therefore, the detection output (first signal) detecting the proximity of the detection target DO and the detection output (second signal) detecting contact with the detection target DO are output from different output lines L1 and L2. This allows the robot controller 13A to perform control (i.e., deceleration control / stop control) based on the input first or second signal, enabling a one-output, one-control configuration. This simplifies the program configuration, allowing for detection of proximity and contact of the detection target with a simple configuration. Furthermore, in this case, since there are two or more output systems, safety-related functions can be made redundant, improving safety.

[0051] In this embodiment, the robot R is controlled so that restarting is not permitted unless both the digital output signals from the first and second detection and conversion circuits 11, 12 become low. This ensures the safety of the worker P when he or she is near the robot R.

[0052] In this embodiment, when setting the distance for each deceleration / stop process according to the distance between the detection target DO and the robot R, the distance can be easily set by setting threshold values ​​individually in the first and second detection / conversion circuits 11 and 12 without having to set the distance on the robot controller 13A side.

[0053] In this embodiment, the first and second detection / conversion circuits 11 and 12 are provided with first and second display units 14 and 15, respectively, so that when attaching the sensor CS to the robot R, the distance can be easily set by checking the display status of the first and second display units 14 and 15 and comparing and adjusting the threshold values ​​of the first and second detection / conversion circuits 11 and 12.

[0054] [Second Example] Fig. 4 shows a schematic block diagram of a control system equipped with a sensor device according to a second embodiment of the present invention, and Fig. 5 is a detailed diagram of a portion of the control system shown in Fig. 4. In each figure, the same reference numerals as those in Figs. 2 and 3 of the first embodiment indicate the same or corresponding parts.

[0055] In this second embodiment, two output lines L1 and L2 are connected to the sensor electrode CS1. The output line L1 is connected to a first detection and conversion circuit (first detection and conversion unit) 11, and the output line L2 is connected to a second detection and conversion circuit (second detection and conversion unit) 12. The first detection and conversion circuit 11 detects the analog output signal of the sensor CS and converts it into a digital signal based on a preset first threshold value, and outputs the digital signal. Similarly, the second detection and conversion circuit 12 detects the analog output signal of the sensor CS and converts it into a digital signal based on a second threshold value that is greater than the first threshold value, and outputs the digital signal. When the detection target DO approaches, the arms Ra1, Ra2, and Ra3 of the robot R are controlled to decelerate, and when the detection target DO comes into contact, the arms Ra1, Ra2, and Ra3 of the robot R are controlled to stop.

[0056] The second embodiment differs from the first embodiment in that a stop switch (preferably an emergency stop switch) 2 is provided. The stop switch 2 is used to stop (preferably in an emergency stop) each of the arms Ra1, Ra2, and Ra3 of the robot R based on a digital output signal from a second detection and conversion circuit 12. The digital output signal of the second detection and conversion circuit 12 is input to the stop switch 2, and the output signal of the stop switch 2 is input to a robot controller 13A of the control unit 13.

[0057] Next, the internal structure of the stop switch 2 will be described with reference to FIGS. Fig. 6 shows the state when the stop switch is not operated, and Fig. 7 shows the state when the stop switch is operated. In these figures, hatching has been omitted for the sake of convenience.

[0058] As shown in Figures 6 and 7, the stop switch 2 comprises a case (housing) 20, a stop button 21 provided at one end of the case 20, supported on the case 20 so as to be axially slidable, and having a pressing surface (manual operation surface) 21a for a pressing operation (manual operation) by an operator P, which can be manually pressed from a position before the pressing operation to a position after the pressing operation, a shaft 22 connected to the back surface opposite the pressing surface 21a of the stop button 21 and extending in the axial direction inside the case 20, a movable contact 23 attached to approximately the center of the shaft 22 and moving together with the shaft 22, a fixed contact 24 fixed to the inner wall surface of the case 20, arranged opposite the movable contact 23, and capable of contacting and separating the movable contact 23, and an electromagnetic solenoid (operating unit) 3 provided at the other end of the case 20 inside the case 20.

[0059] A current is supplied to the electromagnetic coil unit 30 of the electromagnetic solenoid 3 based on an excitation signal, which is a digital output signal from the second detection / conversion circuit 12 (Figs. 4 and 5). An on / off signal, which is generated when the movable contact 23 moves in contact with or away from the fixed contact 24, is input to the robot controller 13A (Fig. 5) of the control unit 13.

[0060] The shaft 22 has a flange 22a that protrudes outward from approximately its center, and one end of a coil spring 25 abuts against the flange 22a. The other end of the coil spring 25 abuts against a protrusion 20a that protrudes inward from the inner wall surface of the case 20. The shaft 22 also has a protrusion 22b that protrudes outward from the inner wall surface of the case 20 near the stop button 21. The protrusion 22b has a trapezoidal cross section and has a pair of inclined surfaces. Meanwhile, a pair of engaging members 26 are provided inside the case 20. Each engaging member 26 has a pair of inclined surfaces that can engage with the inclined surfaces of the protrusion 22b. Each engaging member 26 is urged toward the corresponding protrusion 22b by the elastic repulsive force of a spring 27 disposed inside the case 20. In the non-operated state shown in Figure 6, the inclined surface on the left side of the engaging member 26 engages with the inclined surface on the right side of the protrusion 22b, and in the operated state shown in Figure 7, the inclined surface on the right side of the engaging member 26 engages with the inclined surface on the left side of the protrusion 22b.

[0061] An engaged portion 22A is provided at the tip of the shaft portion 22. In this example, the engaged portion 22A has a cylindrical shape with a larger diameter than the shaft portion 22. A plunger 31 is slidably inserted inside the electromagnetic coil portion 30 of the electromagnetic solenoid 3, and the plunger 31 is arranged concentrically with the shaft portion 22. One end of the plunger 31 is provided with an engaging portion 31A that can engage with the engaged portion 22A of the shaft portion 22. In this example, the engaging portion 31A has a cylindrical shape with a larger diameter than the plunger 31. The engaged portion 22A at the tip of the shaft portion 22 is inserted into and engaged with a hole inside the engaging portion 31A of the plunger 31. With this configuration, the shaft portion 22 and the plunger 31 are connected, and they move together. The electromagnetic solenoid 3 is configured so that the stop button 21 can be pressed from a position before the pressing operation to a position after the pressing operation.

[0062] Next, the effects of this embodiment will be described. The operation of the control system 1 when the detection target DO is located away from the sensor CS, and when the detection target DO is located close to the sensor CS and the detection output of the sensor CS is greater than the first threshold value and less than the second threshold value, is the same as in the first embodiment.

[0063] That is, when the detection target DO is located away from the sensor CS, the first and second detection and conversion circuits 11 and 12 do not output a high digital output signal, and all digital output signals remain low. At this time, the arms Ra1, Ra2, and Ra3 of the robot R are not decelerated (nor stopped) but are operated normally according to the control program, and the first and second display units 14 and 15 are turned off. Also, when the detection target DO is located close to the sensor CS and the detection output of the sensor CS is greater than the first threshold value and less than the second threshold value, the first detection and conversion circuit 11 outputs a high digital output signal (first digital output signal), but the digital output signal of the second detection and conversion circuit 12 remains low. At this time, the first display unit 14 is illuminated green, and the arms Ra1, Ra2, and Ra3 of the robot R are decelerated.

[0064] Next, when the detection object DO is positioned closer to (or in contact with) the sensor CS and the detection output of the sensor CS is greater than the second threshold, a high digital output signal (second digital output signal) is output from the second detection and conversion circuit 12. At this time, the second display unit 15 is illuminated in red, and the first display unit 14 is turned off. The high digital output signal (second digital output signal) output from the second detection and conversion circuit 12 is input to the stop switch 2 (see FIGS. 4 to 6). As a result, a current is supplied to the electromagnetic coil unit 30 of the electromagnetic solenoid 3, and the electromagnetic coil unit is excited.

[0065] 6 and 7, the plunger 31 is retracted and moves to the right in the figure. Accordingly, the shaft 22 connected to the plunger 31 also moves to the right in the figure, and the stop button 21 is pressed from its pre-pressing position to its post-pressing position. As the shaft 22 moves, the inclined surface of the protrusion 22b of the shaft 22 overcomes the inclined surface of the engaging member 26 against the elastic repulsive force of the spring 27. As shown in FIG. 7, the other inclined surface of the protrusion 22b of the shaft 22 engages with the other inclined surface of the engaging member 26. Furthermore, as the movable contact 23 moves together with the shaft 22, the movable contact 23 separates from the fixed contact 24, turning the contact OFF. This OFF signal is input to the robot controller 13A of the control unit 13 (see FIG. 5). As a result, the arms Ra1, Ra2, and Ra3 of the robot R stop.

[0066] As described above, according to this embodiment, two output lines, L1 and L2, are provided, and an emergency stop function is added to one of these output lines (output line L2 in this embodiment). That is, when contact with the detection object DO is detected by sensor CS, a second digital output signal is output from second detection / conversion circuit 12, which is input to stop switch 2, thereby activating electromagnetic solenoid 3 and pressing stop button 21. As a result, in an emergency, even in a situation where worker P cannot directly press stop button 21 of stop switch 2 (for example, when worker P is located far from robot R, or when robot R is a guided robot or an autonomous robot), each arm Ra1, Ra2, Ra3 of robot R can be automatically and immediately brought to an emergency stop.

[0067] In this embodiment, the stop button 21 of the stop switch 2 can only be returned manually from the position after being pressed back to the position before being pressed. That is, the stop button 21 can only be returned by the operator P pulling the stop button 21 toward himself (to the left in FIG. 7). Therefore, in the state shown in FIG. 7, even if the current supply to the electromagnetic coil 30 of the electromagnetic solenoid 3 is stopped, the stop button 21 remains pressed, and the pressed state after the stop button 21 is pressed by the electromagnetic solenoid 3 is maintained unless a manual return operation is performed. As a result, by making the manual return operation of the stop button 21 a condition for restarting the arms Ra1, Ra2, and Ra3 after they have been stopped by the electromagnetic solenoid 3, it is possible to prevent the arms Ra1, Ra2, and Ra3 from being restarted unintentionally by the operator.

[0068] Furthermore, in this embodiment, an excitation signal to the electromagnetic coil unit 30 of the electromagnetic solenoid 3 of the stop switch 2 may be supplied from the robot controller 13A, and the current supply to the electromagnetic solenoid 3 may be maintained unless all the digital output signals (first and second digital output signals) of the first and second detection and conversion circuits 11 and 12 are low. In this way, by setting the condition for stopping the current supply to the electromagnetic solenoid 3 as all the digital output signals of the first and second detection and conversion circuits 11 and 12 being low (i.e., no detection targets such as a worker or an object are in proximity or contact), it is possible to prevent the current supply to the electromagnetic solenoid 3 from being stopped when a worker or the like is located around the arms Ra1, Ra2, and Ra3, and to prevent the stop button 21 from being inadvertently reset. Furthermore, in this case, even if all the digital output signals of the first and second detection / conversion circuits 11, 12 are Low, the pressed state of the stop button 21 after the pressing operation is maintained and the robot R cannot be restarted unless the worker P operates the stop button 21 to return it from the position after the pressing operation to the position before the pressing operation.

[0069] In this embodiment, an excitation signal to the electromagnetic coil unit 30 of the electromagnetic solenoid 3 of the stop switch 2 may be supplied from the robot controller 13A, and the pressed state of the stop button 21 after being pressed by the operation of the electromagnetic solenoid 3 may be maintained as long as all the digital output signals (first and second digital output signals) of the first and second detection and conversion circuits 11 and 12 do not go low. In this way, by setting the condition for restarting each of the arms Ra1, Ra2, and Ra3 after being stopped by the electromagnetic solenoid 3 as being all the digital output signals of the first and second detection and conversion circuits 11 and 12 being low (i.e., no detection targets such as a worker or an object are in proximity or contact), it is possible to prevent each of the arms Ra1, Ra2, and Ra3 from restarting when a worker or the like is located around each of the arms Ra1, Ra2, and Ra3. Furthermore, in this case, even if all the digital output signals of the first and second detection / conversion circuits 11, 12 are Low, the pressed state of the stop button 21 after the pressing operation is maintained and the robot R cannot be restarted unless the worker P operates the stop button 21 to return it from the position after the pressing operation to the position before the pressing operation.

[0070] [Third Example] The schematic block configuration of a control system equipped with a sensor device according to the third embodiment of the present invention is the same as that of the second embodiment shown in Figures 4 and 5, and the configuration of the stop switch (preferably an emergency stop switch) is also the same as that of the second embodiment shown in Figures 6 and 7. However, in this third embodiment, the method of controlling each arm Ra1, Ra2, Ra3 of the robot R when the detection object DO approaches / contacts it is different from that of the second embodiment.

[0071] In the third embodiment, when the detection target DO approaches, the arms Ra1, Ra2, and Ra3 of the robot R temporarily stop based on a digital output signal (first digital output signal) from the first detection and conversion circuit 11, which has undergone threshold processing based on a preset first threshold. Thereafter, when the digital output signal from the first detection and conversion circuit 11 goes low, the arms Ra1, Ra2, and Ra3 of the robot R are permitted to restart and enter a restartable state. Furthermore, when the detection target DO comes into contact with the robot, the stop switch 2 is activated based on a digital output signal (second digital output signal) from the second detection and conversion circuit 12, which has undergone threshold processing based on a second threshold greater than the first threshold. The electromagnetic solenoid 3 then presses the stop button 21, stopping the arms Ra1, Ra2, and Ra3 of the robot R. Even when the digital output signal from the second detection and conversion circuit 12 goes low, the pressed state of the stop button 21, which was pressed by the stop switch 2, is maintained.

[0072] As described above, according to this embodiment, not only can the proximity and contact of the detection target DO be detected with a simple configuration, but when the approach of the detection target DO is detected, each arm Ra1, Ra2, Ra3 of the robot R is temporarily stopped, and as soon as it is confirmed that the approach detection digital signal (first digital output signal) has gone low, each arm Ra1, Ra2, Ra3 of the robot R can be restarted, thereby ensuring the safety of the worker while suppressing a decrease in productivity. Furthermore, when contact of the detection target DO is detected, each arm Ra1, Ra2, Ra3 of the robot R is immediately stopped by the stop switch 2, and thereafter, even if the contact detection digital output signal (second digital output signal) goes low, the pressed state after the stop button 21 was pressed by the operation of the stop switch 2 can be maintained, thereby further improving safety and ensuring the safety of the worker.

[0073] [Fourth Example] 8 shows a schematic block diagram of a control system equipped with a sensor device according to a fourth embodiment of the present invention. In the figure, the same reference numerals as those in the first and second embodiments denote the same or corresponding parts.

[0074] In this fourth embodiment, similarly to the first and second embodiments, two output lines L1 and L2 are connected to the sensor electrode CS1, with the output line L1 connected to a first detection and conversion circuit (first detection and conversion unit) 11 and the output line L2 connected to a second detection and conversion circuit (second detection and conversion unit) 12. The first detection and conversion circuit 11 detects the analog output signal of the sensor CS and converts it into a digital signal based on a preset first threshold value, and outputs the digital signal. Similarly, the second detection and conversion circuit 12 detects the analog output signal of the sensor CS and converts it into a digital signal based on a second threshold value that is greater than the first threshold value, and outputs the digital signal. When the detection object DO approaches, each arm Ra1, Ra2, Ra3 of the robot R is decelerated based on the digital output signal (first digital output signal) from the first detection / conversion circuit 11, and when the detection object DO comes into contact, each arm Ra1, Ra2, Ra3 of the robot R is controlled to stop based on the digital output signal (second digital output signal) from the second detection / conversion circuit 12.

[0075] In the first and second embodiments, the digital output signal of the first detection / conversion circuit 11 is input to the control unit 13 via a wired connection, and the digital output signal of the second detection / conversion circuit 12 is input to the stop switch 2 via a wired connection. However, the fourth embodiment differs from the first and second embodiments in that the digital output signals are configured to be transmitted and received wirelessly.

[0076] 8, the digital output of the first detection / conversion circuit 11 is input to a first transmitter 16. A first battery 13B1 is connected to the first detection / conversion circuit 11 and the first transmitter 16. A first receiver 18 is provided on the control unit 13 side, and the first transmitter 16 and the first receiver 18 are capable of wireless communication. The first receiver 18 is connected to the control unit 13.

[0077] Similarly, the digital output of the second detection and conversion circuit 12 is input to a second transmitter 17. A second battery 13B2 is connected to the second detection and conversion circuit 12 and the second transmitter 17. A second receiver 19 is provided on the control unit 13 side, and the second transmitter 17 and the second receiver 19 are capable of wireless communication. The second receiver 19 is connected to a stop switch (preferably an emergency stop switch) 2, and the output signal of the stop switch 2 is connected to the control unit 13. The stop switch 2 is used to stop (preferably an emergency stop) each of the arms Ra1, Ra2, and Ra3 of the robot R based on the second digital output signal from the second detection and conversion circuit 12, and its configuration is the same as that of the second embodiment.

[0078] As described above, according to this embodiment, two output lines, L1 and L2, are provided, and an emergency stop function is added to one of these output lines (output line L2 in this embodiment). That is, when sensor CS detects contact with the detection target DO, second detection / conversion circuit 12 outputs a second digital output signal, which is input to stop switch 2 via second transmitter 17 and second receiver 19, activating the electromagnetic solenoid and pressing the stop button. As a result, in an emergency, even in a situation where worker P cannot directly press the stop button of stop switch 2 (for example, when worker P is located far from robot R or when robot R is a guided robot or an autonomous robot), each arm Ra1, Ra2, and Ra3 of robot R can be automatically and immediately brought to an emergency stop.

[0079] According to this embodiment, not only is the second digital output signal from the second detection and conversion circuit 12 transmitted and received wirelessly via the second transmitter 17 and the second receiver 19, but the first digital output signal from the first detection and conversion circuit 11 is transmitted and received wirelessly via the first transmitter 16 and the first receiver 18. As a result, not only can the second digital output signal output from the second detection and conversion circuit 12 be wirelessly transmitted when the detection object DO is in contact with the sensor CS, but also the first digital output signal output from the first detection and conversion circuit 11 when the detection object DO is in close proximity to the sensor CS can be wirelessly transmitted. This alleviates restrictions on where the sensor CS can be installed, enabling the entire control system to be cordless.

[0080] In this embodiment, as in the second embodiment, the return operation from the position after the stop button of the stop switch 2 is pressed back to the position before the press operation can only be performed manually. Therefore, even if the supply of current to the electromagnetic solenoid of the stop switch 2 is stopped, the stop button remains pressed, and the pressed state after the stop button is pressed by the operation of the electromagnetic solenoid is maintained unless a manual return operation is performed.

[0081] Furthermore, in this embodiment, an excitation signal to the electromagnetic solenoid of the stop switch 2 may be supplied from the control unit 13, and the supply of current to the electromagnetic solenoid may be maintained unless all of the digital output signals (first and second digital output signals) of the first and second detection and conversion circuits 11 and 12 are Low. Furthermore, in this case, even if all of the digital output signals of the first and second detection and conversion circuits 11 and 12 are Low, the pressed state of the stop button after being pressed is maintained, and the robot R cannot be restarted unless the worker P returns the stop button from the position after being pressed to the position before being pressed.

[0082] In this embodiment, an excitation signal to the electromagnetic solenoid of the stop switch 2 may be supplied from the control unit 13, and the pressed state of the stop button after it has been pressed by the activation of the electromagnetic solenoid may be maintained unless all of the digital output signals (first and second digital output signals) of the first and second detection and conversion circuits 11 and 12 become Low. Furthermore, in this case, even if all of the digital output signals of the first and second detection and conversion circuits 11 and 12 are Low, the pressed state of the stop button after it has been pressed is maintained and the robot R cannot be restarted unless the worker P returns the stop button from the position after it has been pressed to the position before it was pressed.

[0083] Fifth Example 9 shows a schematic block diagram of a control system equipped with a sensor device according to a fifth embodiment of the present invention. In the figure, the same reference numerals as those in the first, second and fourth embodiments indicate the same or corresponding parts.

[0084] The fifth embodiment differs from the second embodiment in that a transmitter 1 (CSt1), a transmitter 2 (CSt2), and a receiver CSr are provided instead of the sensor CS of the second embodiment. The receiver CSr is installed on the robot arm and functions as a distance sensor (sensor) to receive radio signals wirelessly transmitted from transmitters 1 (CSt1) and 2 (CSt2), respectively, carried by different workers, and measure their strength (received signal strength). Bluetooth (registered trademark), for example, is used as a wireless communication standard. The received signal strength is generally expressed using RSSI (Received Signal Strength Indication). A high RSSI value indicates a short distance from each of transmitters 1 and 2 to the receiver (sensor) CSr, whereas a low RSSI value indicates a long distance from each of transmitters 1 and 2 to the receiver (sensor) CSr.

[0085] In the fifth embodiment, similarly to the first, second, and fourth embodiments, two output lines L1 and L2 are connected to a receiver (sensor) CSr, with the output line L1 connected to a first detection and conversion circuit (first detection and conversion unit) 11 and the output line L2 connected to a second detection and conversion circuit (second detection and conversion unit) 12. The first detection and conversion circuit 11 detects an analog output signal of the receiver CSr and converts it into a digital signal based on a preset first threshold value, and outputs the digital signal. Similarly, the second detection and conversion circuit 12 detects the analog output signal of the receiver CSr and converts it into a digital signal based on a second threshold value that is greater than the first threshold value, and outputs the digital signal. When the detection object DO approaches, each arm Ra1, Ra2, Ra3 of the robot R is decelerated based on the digital output signal (first digital output signal) from the first detection / conversion circuit 11, and when the detection object DO comes into contact, each arm Ra1, Ra2, Ra3 of the robot R is controlled to stop based on the digital output signal (second digital output signal) from the second detection / conversion circuit 12.

[0086] FIG. 10 is an example of a graph showing the relationship between the distance (m) between the worker carrying transmitters 1 and 2 and the robot arm equipped with receiver CSr in control system 1 (FIG. 9), with the horizontal axis representing the distance and the vertical axis representing the received signal strength RSSI (dBm) received by receiver CSr. As shown in the figure, the shorter the distance, the greater the received signal strength RSSI. In this example, an area at a distance of 4 m or more is defined as a safe area where the robot operates normally, an area at a distance of 2 m or more but less than 4 m is defined as a deceleration area where the robot operates at a reduced speed (an area outside the robot's range of motion but accessible to workers and corresponding to the robot's monitored area), and an area at a distance of 0 m or more but less than 2 m is defined as a stop area where the robot is forced to stop (an area within the robot's range of motion that workers are prohibited from entering). Therefore, the first threshold value set in the first detection / conversion circuit 11 is a received signal strength of -45 (dBm), which corresponds to a distance of 4 m, and the second threshold value set in the second detection / conversion circuit 12 is a received signal strength of -40 (dBm), which corresponds to a distance of 2 m.

[0087] Next, the effects of this embodiment will be described. When worker P approaches robot R, transmitters 1 and 2 carried by worker P are detected by receiver CSr. Then, the detection output from receiver CSr is output to output lines L1 and L2 and input to first and second detection and conversion circuits 11 and 12 for detection. Here, first and second thresholds are set in first and second detection and conversion circuits 11 and 12, respectively, to threshold process the analog output signal from receiver CSr, and the first threshold is smaller than the second threshold.

[0088] Now, for example, when a worker carrying transmitter 2 (CSt2) is located more than 4 m away from receiver CSr, the detection output of transmitter 2 is smaller than the first threshold, so that the first detection / conversion circuit 11 does not output a high digital output signal, and similarly the second detection / conversion circuit 12 does not output a high digital output signal, and all digital output signals remain low. At this time, the robot arm does not slow down (nor stop) and continues to operate normally in accordance with the control program. Also, at this time, the displays 14 and 15 are turned off.

[0089] Next, when the worker P carrying the transmitter 2 is located at a distance of 2 m or more but less than 4 m from the receiver CSr, the detection output of the receiver CSr is greater than the first threshold value and less than the second threshold value, so that a high digital output signal (first digital output signal) is output from the first detection and conversion circuit 11. At this time, the first display unit 14 illuminates, for example, green. Meanwhile, the second detection and conversion circuit 12 does not output a high digital output signal and remains low. At this time, the second display unit 15 is in an unlit state. The high digital output signal (first digital output signal) output from the first detection and conversion circuit 11 is input to the control unit 13. As a result, the robot arm is controlled and shifts to a deceleration operation mode. Note that this deceleration operation mode may be further subdivided to provide a low-speed operation mode and a medium-speed operation mode.

[0090] Next, when the worker carrying the transmitter 1 (CSt1) is at a position 0 m or more but less than 2 m away from the receiver CSr, the detection output of the receiver CSr is greater than the second threshold, and so a high digital output signal (second digital output signal) is output from the second detection and conversion circuit 12. At this time, the second display unit 15 illuminates, for example, red, and the first display unit 14 is turned off. The high digital output signal (second digital output signal) output from the second detection and conversion circuit 12 is input to the stop switch 2. As a result, the robot arm is driven and controlled to stop.

[0091] As described above, according to this embodiment, two output lines, L1 and L2, are provided, and an emergency stop function is added to one of these output lines (output line L2 in this embodiment). That is, when the receiver CSr detects contact of the worker P with the robot arm, the second detection / conversion circuit 12 outputs a second digital output signal, which is input to the stop switch 2, activating the electromagnetic solenoid and pressing the stop button. As a result, in an emergency, even in a situation where the worker P cannot directly press the stop button of the stop switch 2 (for example, when the worker P is located far from the robot R, or when the robot R is a guided robot or an autonomous robot), the robot arm can be automatically and immediately brought to an emergency stop.

[0092] In this embodiment as well, the return operation from the position after the stop button of the stop switch 2 is pressed back to the position before the press operation can only be performed manually. Even if the supply of current to the electromagnetic solenoid of the stop switch 2 is stopped, the stop button remains pressed, and the pressed state after the stop button is pressed by the operation of the electromagnetic solenoid is maintained unless a manual return operation is performed.

[0093] In this embodiment, too, an excitation signal to the electromagnetic solenoid of the stop switch 2 may be supplied from the control unit 13, and the current supply to the electromagnetic solenoid may be maintained as long as all digital output signals (first and second digital output signals) of the first and second detection and conversion circuits 11 and 12 are not low (i.e., as long as all workers are not more than 4 m away from the receiver CSr). In this way, by setting the condition for stopping the current supply to the electromagnetic solenoid as being that all digital output signals of the first and second detection and conversion circuits 11 and 12 are low (i.e., that the worker P is not in proximity or contact), it is possible to prevent the current supply to the electromagnetic solenoid from being stopped while the worker is located around the robot arm, and to prevent the stop button from being inadvertently reset. Furthermore, in this case, even if all the digital output signals of the first and second detection / conversion circuits 11, 12 are Low, the pressed-in state of the stop button after the pressing operation is maintained and the robot R cannot be restarted unless the worker P returns the stop button from the position after the pressing operation to the position before the pressing operation.

[0094] In this embodiment, it is preferable that the stop switch 2 is placed at a position 4 m or more away from the receiver CSr. In this case, when the worker P manually resets the stop switch 2, the worker P works in a safe area, which improves work safety and makes it possible to restart the robot R from a safe position.

[0095] Furthermore, this embodiment is more suitable for a conventional robot that works apart from the worker P within an area surrounded by a safety fence than for a collaborative robot that works in cooperation with the worker P. This is because, after an emergency stop, after all the workers have evacuated to the outside of the safety fence (at this time, the strength of the received signals from the transmitters of all the workers has decreased), the stop switch 2 installed outside the safety fence can be reset, thereby reducing the risk of the worker P remaining inside the safety fence.

[0096] [Sixth Example] 11 shows a schematic block diagram of a control system equipped with a sensor device according to a sixth embodiment of the present invention. In the figure, the same reference numerals as those in the first, second, fourth and fifth embodiments indicate the same or corresponding parts.

[0097] The sixth embodiment is configured by adding a ticket unit / charging unit (hereinafter simply referred to as "unit") 4 to the fifth embodiment. Transmitters 1 (CSt1), 2 (CSt2), and 3 (CSt3) are physically connectable and detachable to unit 4. Each worker P must remove transmitters 1-3 from unit 4 and carry them when entering the safety fence. Transmitters 1-3 function as a ticket (permit ticket) for the worker P to enter the safety fence. The gate of the safety fence is not permitted to open unless the worker P is carrying one of transmitters 1-3 and the stop switch 2 is turned off. If one worker P carries multiple transmitters 1-3 and the transmitters are close to each other, a warning message may be displayed to alert the worker P or the robot may not be allowed to restart.

[0098] Although not shown, a receiver equivalent to the receiver CSr in the fifth embodiment is connected to unit 4. After transmitters 1 to 3 are removed from unit 4, the receiver receives the radio wave signals wirelessly transmitted from transmitters 1 to 3, measures their strength (received signal strength), and functions as a distance sensor. Also, although not shown, first to third detection and conversion circuits are connected to the receiver for threshold processing of the received signals from transmitters 1 to 3, with different thresholds set for each. When a worker approaches the robot, transmitters 1 to 3 are detected by the receiver, and the first to third detection and conversion circuits threshold process the analog output signals from the receivers and output them digitally, thereby controlling the drive of the robot arm.

[0099] Unit 4 is connected to the terminal of stop switch 2. After completing work within the safety fence, all workers leave the safety fence and connect all transmitters 1 to 3 to unit 4. Robot R will not be allowed to restart unless a safety output from the safety switch (interlock device) due to the safety fence gate being closed and a safety signal output due to the manual reset operation of stop switch 2 are detected.

[0100] In addition, if the stop switch 2 is located near the robot R inside the safety fence, the return operation of the stop switch 2 may be performed remotely, such as by radio, only when a safety output is output from the safety switch (interlock device) by closing the gate of the safety fence and all transmitters 1 to 3 are connected to the unit 4.

[0101] An ID reader 40 is connected to unit 4. If the unique ID of worker P is requested when transmitters 1 to 3 are removed from unit 4, the unique ID of worker P may be linked to the unique IDs of transmitters 1 to 3 and registered, and the unique ID of worker P may be read by ID reader 40. Furthermore, if the unique ID of worker P is requested again when transmitters 1 to 3 are returned to unit 4, the risk of worker P remaining inside the safety fence after work is completed can be reduced.

[0102] [First Modification] In the first to fifth embodiments, examples have been shown in which two output lines L1 and L2 are connected to the sensor CS or the receiver (sensor) CSr, but the application of the present invention is not limited to this, and three or more output lines may be connected to the sensor (see the fifth embodiment).

[0103] [Second Modification] In the above embodiments, the sensor is described as being capable of being wrapped around a robot arm, but the application of the present invention is not limited to this. A sheet-like sensor may be attached to the robot R in an unfolded state.

[0104] [Third Modification] As sensors according to the present invention, the first to fourth embodiments have been described using a capacitive proximity sensor as an example, and the fifth and sixth embodiments have been described using a distance sensor as an example, but the application of the present invention is not limited to these, and the present invention can also be applied to other proximity sensors (such as magnetic types), various non-contact sensors, and RFID.

[0105] [Other Modifications] The above-described embodiments and modifications are to be considered in all respects as merely illustrative of the present invention, and not restrictive. Those skilled in the art to which the present invention pertains will be able to devise various modifications and other embodiments that incorporate the principles of the present invention, even if not expressly described herein, without departing from the spirit and essential characteristics of the present invention, when taking into account the teachings set forth above.

[0106] [Other application examples] In the above-described embodiments and modifications, the arm of a vertical articulated robot has been described as an example of a moving part of a machine to which the sensor device of the present invention is applied, but the application of the present invention is not limited to this. The sensor device of the present invention may also be provided on the arms of other robots, such as horizontal articulated robots, SCARA robots, and various other robots, or on moving parts of industrial vehicles such as the bucket of a hydraulic excavator. It may also be provided on the bumper of an automatic guided vehicle (AGV) or autonomous mobile robot (AMR). In the case of an automatic guided vehicle, the bumper itself does not move relative to the vehicle body, but since the bumper moves with the vehicle, it is included in the moving part. [Industrial Applicability]

[0107] The present invention is useful for a sensor device that detects the proximity of a detection target, such as a person, to a moving part of a machine, and is particularly suited to those that require a simplified structure. [Explanation of symbols]

[0108] 1: Control System 10: Sensor device 11: First detection and conversion circuit (first detection and conversion unit) 12: Second detection and conversion circuit (second detection and conversion unit) 13: Control section 2: Emergency stop switch (stop switch) 21: Stop button 3: Electromagnetic solenoid (actuator) DO: Detection target CS: Sensor CSr: Distance sensor (sensor) L1, L2: Output line R: Robot (machine) Ra1~Ra3: Arm (moving part) [Prior art documents] [Patent documents]

[0109] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-43792 (see paragraphs

[0004] ,

[0005] ,

[0007] ,

[0008] and Figures 1 to 4) [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-149673 (see paragraphs

[0018] ,

[0021] ,

[0025] ,

[0030] , and Figures 1 to 5 and 8)

Claims

1. A sensor device, a sensor for detecting a detection target; At least two output lines provided on the sensor; a detection and conversion unit connected to each of the output lines, detecting an analog output signal from each of the sensors, and having different thresholds set thereto, converting the analog output signal from each of the sensors into a digital signal based on the thresholds and outputting the digital signal; A sensor device comprising:

2. In claim 1, one of the thresholds is for detecting the proximity of the detection object, and the other of the thresholds is for detecting the contact of the detection object; A sensor device characterized by:

3. A control system including the sensor device according to claim 1, the detection and conversion unit is composed of a first detection and conversion unit that outputs a first digital output signal based on a first threshold value, and a second detection and conversion unit that outputs a second digital output signal based on a second threshold value that is greater than the first threshold value; a control unit configured to decelerate a moving part of the machine based on the first digital output signal from the first detection / conversion unit, and to stop the moving part of the machine based on the second digital output signal from the second detection / conversion unit; A control system comprising:

4. A control system including the sensor device according to claim 1, Equipped with a stop switch to stop the moving parts of the machine, the stop switch has a stop button that can be manually pressed from a position before the pressing operation to a position after the pressing operation, and an actuation portion that can be manually pressed to move the stop button from the position before the pressing operation to the position after the pressing operation, the detection and conversion unit is composed of a first detection and conversion unit that outputs a first digital output signal based on a first threshold value, and a second detection and conversion unit that outputs a second digital output signal based on a second threshold value that is greater than the first threshold value; The moving part of the machine is decelerated based on the first digital output signal from the first detection / conversion unit, and the actuation part of the stop switch is actuated based on the second digital output signal from the second detection / conversion unit, thereby controlling the stop button to be pressed and the moving part of the machine to be stopped. A control system comprising:

5. In claim 4, The stop button can be manually returned from the position after the pressing operation to the position before the pressing operation. A control system comprising:

6. In claim 4, The pressed state of the stop button after the pressing operation by the actuation of the actuation unit is maintained unless the return operation is performed manually. A control system comprising:

7. In claim 4, the pressed state of the stop button after the pressing operation by the actuation of the actuation unit is maintained unless all the digital output signals of the detection / conversion units become Low; A control system comprising:

8. In claim 4, the actuation unit is composed of an electromagnetic solenoid, and current supply to the electromagnetic solenoid is maintained unless all of the digital output signals of the detection / conversion units are Low; A control system comprising:

9. A control system including the sensor device according to claim 1, Equipped with a stop switch to stop the moving parts of the machine, the stop switch has a stop button that can be manually pressed from a position before the pressing operation to a position after the pressing operation, and an actuation portion that can be manually pressed to move the stop button from the position before the pressing operation to the position after the pressing operation, the detection and conversion unit is composed of a first detection and conversion unit that outputs a first digital output signal based on a first threshold value, and a second detection and conversion unit that outputs a second digital output signal based on a second threshold value that is greater than the first threshold value; after stopping the moving part of the machine based on the first digital output signal from the first detection and conversion unit, allowing the moving part of the machine to be restarted when the digital output signal from the first detection and conversion unit becomes Low; the actuation unit of the stop switch is actuated based on the second digital output signal from the second detection / conversion unit, and after the stop button is pressed to stop the moving part of the machine, the actuation unit is controlled to maintain the pressed state of the stop button after the pressing operation even if the digital output signal of the second detection / conversion unit becomes Low. A control system comprising:

10. In claim 4, The stop switch is an emergency stop switch. A control system comprising:

11. In claim 3 or 4, The machine is a collaborative robot or an automated guided vehicle that works in collaboration with a worker. A control system comprising:

12. A control system, comprising: a receiver for detecting a transmitter carried by each worker; two output lines provided on the receiver; a first detection and conversion unit connected to each of the output lines, detecting an analog output signal from the receiver, converting the analog output signal into a first digital output signal based on a first threshold, and outputting the first digital output signal; and a second detection and conversion unit converting the analog output signal into a second digital output signal based on a second threshold greater than the first threshold, Further provided with a stop switch for stopping the machine; the stop switch has a stop button that can be pressed down and an actuating portion that can press down the stop button from a position before the pressing operation to a position after the pressing operation, The machine is decelerated based on the first digital output signal from the first detection / conversion unit, and the operation unit of the stop switch is operated based on the second digital output signal from the second detection / conversion unit to press the stop button and stop the machine. A control system comprising:

13. In claim 12, Even if the second digital output signal of the second detection / conversion unit becomes Low, the pressed state of the stop button after the pressing operation due to the operation of the operation unit is maintained. A control system comprising:

14. In claim 12, The stop button can be manually returned from the position after the pressing operation to the position before the pressing operation. A control system comprising:

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