robot systems

Abstract

This invention provides a robot system capable of calibrating sensor values ​​that have an offset component that fluctuates due to environmental factors. [Solution] The robot system 10 comprises a robot 1, a sensor 2 provided on the robot 1 that outputs a sensor value corresponding to the capacitance generated between it and an object, a monitoring sensor 3 that monitors objects around the sensor 2, and a control device 4 that determines the presence or absence of objects around the sensor 2 based on the monitoring results of the monitoring sensor 3, and performs calibration of the sensor value when it is determined that there are no objects around the sensor 2.

Description

Technical Field

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

Background Art

[0002] There are cases where a person and a robot cooperate to perform work on a workpiece. A robot used in such a case is called a collaborative robot. For example, in a collaborative robot, a capacitance sensor may be mounted to detect an object nearby.

[0003] Also, in Patent Document 1, there is described a capacitance sensor for measuring the storage amount of a measurement object in a container, and zero adjustment is performed by providing a sensor electrode and a ground electrode at a certain distance from each other.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the capacitance sensor forms a capacitance with an object nearby, an offset component may occur in the sensor value due to environmental factors such as temperature and humidity. For example, although Patent Document 1 describes performing zero adjustment, it is for the purpose of measuring the storage amount, and it is necessary to provide the sensor electrode and the ground electrode separated by a certain distance as a set. Therefore, it is difficult to apply the method of Patent Document 1 to a robot provided with a capacitance sensor. Also, since the offset component may drift (fluctuate) due to changes in environmental factors, it is required to calibrate the sensor value in response to the fluctuating offset component.

[0006] In view of the above issues, the present invention aims to provide a robot system that can perform calibration on sensor values ​​that have an offset component that fluctuates due to environmental factors. [Means for solving the problem]

[0007] To solve the above problems, the robot system according to the present invention comprises a robot, a sensor provided on the robot that outputs a sensor value corresponding to the capacitance generated between it and an object, a monitoring sensor that monitors objects around the sensor, and a control device that determines the presence or absence of objects around the sensor based on the monitoring results of the monitoring sensor, and performs calibration of the sensor value when it is determined that there are no objects around the sensor.

[0008] Furthermore, in the robot system, the control device performs zero-point adjustment of the sensor value when it determines that there are no objects around the sensor.

[0009] Furthermore, in the robot system, the sensor has a bridge circuit including a detection electrode that generates an electric field in a predetermined direction, and the control device adjusts the equilibrium state of the bridge circuit to calibrate the sensor value.

[0010] Furthermore, in the robot system, the bridge circuit includes a first resistor and a second resistor, and the control device adjusts the resistance value of at least one of the first resistor and the second resistor to perform zero-point adjustment of the sensor value.

[0011] Furthermore, in the robot system, the control device switches between a detection mode, in which object detection is performed using the sensor value, and a calibration mode, in which the sensor value is calibrated, based on the determination result of whether or not there are objects around the sensor. [Effects of the Invention]

[0012] According to the robot system of the present invention, calibration can be performed on sensor values ​​that have an offset component that fluctuates due to environmental factors. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing an example of the overall configuration of a robot system according to an embodiment of the present invention. [Figure 2] This figure shows an example of the specific configuration of the sensor shown in Figure 1. [Figure 3] This figure shows an example of various functions in the control device shown in Figure 1. [Figure 4] Figure 1 is a flowchart showing an example of processing by the control device. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the attached drawings. In order to facilitate understanding of the explanation, the same reference numerals will be used for identical components in each drawing as much as possible, and redundant explanations will be omitted as appropriate.

[0015] ===Implementation Method=== <Overall Structure> Figure 1 is a schematic diagram showing an example of the overall configuration of a robot system 10 according to one embodiment of the present invention.

[0016] The robot system 10 is an industrial robot that performs tasks on a workpiece, such as processing or transporting it. Furthermore, the robot system 10 is a collaborative robot that works in the same space as a human, for example.

[0017] As shown in Figure 1, the robot system 10 mainly consists of a robot 1, a sensor 2, a monitoring sensor 3, and a control device 4.

[0018] Robot 1 is an articulated robot and has a plurality of arms and a plurality of joints. Specifically, robot 1 includes a base 7, a first arm A1, a second arm A2, a third arm A3, and a fourth arm A4. Note that the number of arms provided is not limited. The base 7 is the base of robot 1. The base 7 is fixed to, for example, a floor surface or a wall surface and supports the entire robot 1. The first arm A1 is connected to the base 7 via a rotating shaft. And the first arm A1 rotates around the rotating shaft with respect to the base 7 by a motor (not shown). The second arm A2, the third arm A3, and the fourth arm A4 rotate around the rotating shaft by respective motors (not shown) in the same manner as the first arm A1. A tool or the like is provided at the tip of the fourth arm A4. In this way, the arms are connected to other arms or the like with the rotating shaft as a joint and are operable. When each joint is movable, robot 1 performs a predetermined operation.

[0019] Sensor 2 is a capacitance-type sensor that detects an object such as a person non-contact. Sensor 2 outputs a sensor value corresponding to the capacitance generated between the sensor and the object. In the present embodiment, "object" is a broad concept including a human or an object such as a workpiece. For example, sensor 2 detects the proximity of an object. Note that sensor 2 may detect the displacement of an object. The present embodiment takes the case where sensor 2 detects the proximity of an object as an example. The sensor value is, for example, the output voltage output from sensor 2.

[0020] Sensor 2 is provided for robot 1. Specifically, sensor 2 is provided on the arm of robot 1. In the present embodiment, the case where sensor 2 is provided on the fourth arm A4 is described as an example. Note that the installation position and the number of installations of sensor 2 on robot 1 shown in FIG. 1 are examples, and the installation position and the number of installations of sensor 2 are not limited to the specific example shown in FIG. 1.

[0021] FIG. 2 is a diagram showing an example of the specific configuration of the sensor 2. The sensor 2 includes an arbitrary waveform generator 21, a first resistor section 22, a capacitor section 23, a second resistor section 24, a detection electrode 25, an instrumentation amplifier 26, a lock-in amplifier 27, and an A / D converter 28. The first resistor section 22, the capacitor section 23, the second resistor section 24, and the detection electrode 25 constitute a bridge circuit 29. The bridge circuit 29 is, for example, an RC bridge circuit.

[0022] The arbitrary waveform generator 21 is a transmission circuit that uses the ground potential (GND potential) as a reference potential and generates a sine wave voltage or a rectangular wave voltage at a predetermined frequency. The signal generated by the arbitrary waveform generator 21 is input to the bridge circuit 29. Specifically, one side of the first resistor section 22 is electrically connected to the arbitrary waveform generator 21, and the other side is electrically connected to the capacitor section 23. One side of the capacitor section 23 is electrically connected to the first resistor section 22, and the other side is electrically connected to the reference potential of the arbitrary waveform generator 21. The point between the first resistor section 22 and the capacitor section 23 is designated as point P1. One side of the second resistor section 24 is electrically connected to the arbitrary waveform generator 21, and the other side is electrically connected to the detection electrode 25. The point between the second resistor section 24 and the detection electrode 25 is designated as point P2. The first resistor section 22 and the second resistor section 24 are variable resistor sections with variable resistance values. For example, the first resistor section 22 and the second resistor section 24 are configured using digital potentiometers. The resistance values of the first resistor section 22 and the second resistor section 24 are adjusted by a control device 4 described later. The value of the capacitor section 23 is set in advance. Note that each of the first resistor section 22 and the second resistor section 24 may be configured by one resistor (variable resistor), or may be configured using a plurality of resistors. The capacitor section 23 may be configured by one capacitor, or may be configured using a plurality of capacitors. The bridge circuit 29 is designed to be in an equilibrium state when the sensor 2 does not detect an object (when there is no object around the detection electrode 25). The equilibrium state means that the voltage at point P1 is equal to the voltage at point P2.

[0023] The detection electrode 25 is electrically connected to the second resistor 24. For example, the detection electrode 25 is flat and has a planar shape such as a rectangle. The shape of the detection electrode 25 may be designed to match the outer shape of the arm, for example, and the specific shape is not limited. The sensor 2 generates an electric field from the detection electrode 25 in a predetermined direction. Specifically, the sensor 2 generates an electric field on the side opposite to the main body of the robot 1 to which it is attached. That is, the sensor 2 generates an electric field around the robot 1. The detection electrode 25 then forms a capacitance with a nearby object. The capacitance changes depending on the distance between the detection electrode 25 and the object. Figure 2 shows a person H as an example of an object. It is assumed that the potential of person H is equivalent to the reference potential. The detection electrode 25 forms a capacitance with person H and forms part of the bridge circuit 29. A shield electrode or active shield electrode may be provided on the side opposite to the direction in which the electric field is generated (towards the main body of the robot 1) relative to the detection electrode 25.

[0024] The instrumentation amplifier 26 has its negative input terminal electrically connected to point P1 between the first resistor 22 and the capacitance 23, and its positive input terminal electrically connected to point P2 between the second resistor 24 and the detection electrode 25. The instrumentation amplifier 26 differentially amplifies the inputs from the positive and negative input terminals. The output terminal of the instrumentation amplifier 26 is electrically connected to the lock-in amplifier 27. The differentially amplified signal is synchronously detected in the lock-in amplifier 27 and converted from an analog signal to a digital signal in the A / D converter 28. The lock-in amplifier 27 uses the signal from the arbitrary waveform generator 21 as a reference signal for synchronous detection. Thus, the sensor value output from the sensor 2 corresponds to the capacitance generated according to the state (distance) between the detection electrode 25 and the object. The bridge circuit 29 is designed to be in an ideally balanced state when the sensor 2 does not detect an object, so the sensor value when no object is detected is zero (the reference value for the ideal state).

[0025] Furthermore, the specific circuit configuration of the sensor 2 is not limited to Figure 2, as long as a sensor value corresponding to the capacitance formed at the detection electrode 25 is output. Also, the sensor value is not limited to the output of the A / D converter 28; the output of the lock-in amplifier 27, etc., may also be used as the sensor value.

[0026] The monitoring sensor 3 monitors objects around sensor 2. In this embodiment, the monitoring sensor 3 is a camera (imaging device) such as a 3D camera. Note that the monitoring sensor 3 can also be an infrared camera or optical sensor, as long as it can monitor objects.

[0027] The monitoring sensor 3 takes images of a predetermined range around sensor 2 (the vicinity of sensor 2). The predetermined range is set to include, for example, the range of the electric field generated by sensor 2. In other words, the monitoring sensor 3 monitors the range in which sensor 2 can detect objects.

[0028] The monitoring sensor 3 is installed on the top of the robot 1, for example, as shown in Figure 1. This allows the monitoring sensor 3 to monitor the presence or absence of objects around the sensor 2 mounted on the robot 1 from above.

[0029] The monitoring results from the monitoring sensor 3 are output to the control device 4.

[0030] The control device 4 is an information processing device that controls the movement of the robot 1. In this embodiment, the control device 4 also calibrates the sensor 2. The control device 4 is configured to include, for example, a CPU, memory, communication device, and storage device, and performs various functions by executing a predetermined program.

[0031] <Functional configuration> Figure 3 shows an example of the various functions of the control device 4. The control device 4 comprises an acquisition unit 30, a control unit 31, a determination unit 32, a mode switching unit 33, and a calibration unit 34.

[0032] The acquisition unit 30 acquires sensor values ​​from sensor 2. The acquisition unit 30 also acquires monitoring results from monitoring sensor 3. For example, the acquisition unit 30 acquires an image showing the surrounding conditions of sensor 2, which is captured by monitoring sensor 3.

[0033] The control unit 31 controls the movement of the robot 1. Specifically, the control unit 31 controls the movement of each arm of the robot 1 to cause the robot 1 to perform a predetermined action. The predetermined action is, for example, an action performed on a workpiece. That is, the control unit 31 controls the rotation of each pivot axis that constitutes each joint of the robot 1.

[0034] Furthermore, the control unit 31 uses the sensor value obtained from the sensor 2 to stop the robot 1's movement. Specifically, the control unit 31 compares the sensor value with a threshold value to determine whether or not an object is in close proximity to the robot 1. If the control unit 31 determines that an object is in close proximity to the robot 1, it stops the robot 1's movement. For example, if the sensor value increases in response to the approach of an object, the control unit 31 stops the robot 1's movement when the sensor value exceeds the threshold value. The control unit 31 also stops the robot 1's movement even if it is in the middle of a predetermined operation. Note that the control unit 31 is not limited to stopping the robot 1's movement; it may also slow down the robot 1's movement or cause the robot 1 to perform an action to avoid the object.

[0035] The determination unit 32 determines the presence or absence of objects around sensor 2 based on the monitoring results of the monitoring sensor 3. Specifically, the determination unit 32 refers to the captured image showing the surrounding conditions of sensor 2 and determines whether or not there are objects around sensor 2. For example, if the image shows that there are objects around sensor 2, the determination unit 32 determines that there are objects around sensor 2. In this case, it means that there is a high probability that there are objects around sensor 2. Also, if the image shows that there are no objects around sensor 2, the determination unit 32 determines that there are no objects around sensor 2. In this case, it means that there is a high probability that there are no objects around sensor 2. In this way, the determination unit 32 determines whether or not there are objects inside the electric field generated by sensor 2 (within the object detection range). That is, it determines whether or not sensor 2 is detecting a nearby object. If there are objects around sensor 2, the sensor value will be a value corresponding to the capacitance generated between the detection electrode 25 and the object. Furthermore, the sensor value is the value obtained when there are no objects around sensor 2 and when the detection electrode 25 does not form capacitance with an object.

[0036] The mode switching unit 33 switches between detection mode and calibration mode based on the determination result of whether or not there are objects around the sensor 2. Specifically, if the determination unit 32 determines that there are objects around the sensor 2, the mode switching unit 33 selects detection mode. If the determination unit 32 determines that there are no objects around the sensor 2, the mode switching unit 33 selects calibration mode. Then, when the determination result of whether or not there are objects around the sensor 2 changes, the mode switching unit 33 switches between detection mode and calibration mode.

[0037] The detection mode is an operating mode in which object detection is performed using sensor values ​​obtained from sensor 2. Specifically, in detection mode, the control unit 31 uses the sensor values ​​to determine whether or not an object is in close proximity to robot 1, and controls the stopping of robot 1's movement. Note that in detection mode, the sensor value calibration described later is not performed.

[0038] The calibration mode is an operating mode in which the sensor values ​​output from sensor 2 are calibrated. Specifically, in calibration mode, the calibration unit 34, which will be described later, calibrates sensor 2. Note that in calibration mode, the control unit 31 does not perform stop control of the robot 1's movement using the sensor values.

[0039] The calibration unit 34 performs calibration of the sensor value. The sensor value may have an offset component due to environmental factors such as temperature and humidity. This is because the capacitance generated in the sensing electrode 25 is affected by the surrounding environment. In addition, the offset component of the sensor value drifts (fluctuations) due to changes in environmental factors. Therefore, the calibration unit 34 calibrates the sensor value in order to suppress the offset component that has drifted due to environmental factors.

[0040] Specifically, the calibration unit 34 performs calibration of the sensor value when it is determined that there are no objects around the sensor 2. For example, the calibration unit 34 performs zero-point adjustment as part of the calibration. That is, the calibration unit 34 performs calibration so that the sensor value approaches the zero point. When there are no objects around the sensor 2, ideally the bridge circuit 29 is in equilibrium, and the sensor value becomes zero (reference value). However, even when there are no objects around the sensor 2, an offset component appears in the sensor value due to environmental factors. That is, the sensor value when it is determined that there are no objects around the sensor 2 shows an offset component. For this reason, the calibration unit 34 performs zero-point adjustment of the sensor value based on the sensor value when it is determined that there are no objects around the sensor 2. The calibration unit 34 performs calibration so that the sensor value becomes zero when it is determined that there are no objects around the sensor 2.

[0041] Specifically, the calibration unit 34 refers to the sensor value when it is determined that there are no objects around the sensor 2, and adjusts the equilibrium state of the bridge circuit 29 so that the sensor value becomes zero. To adjust the bridge circuit 29, the calibration unit 34 adjusts the resistance value of at least one of the first resistor 22 and the second resistor 24. That is, the calibration unit 34 adjusts the first resistor 22 and the second resistor 24 by referring to the sensor value, and adjusts the bridge circuit 29, which includes the detection electrode 25 that is affected by environmental factors, to be in an equilibrium state. The adjustment of the first resistor 22 and the second resistor 24 is completed when the sensor value becomes zero when it is determined that there are no objects around the sensor 2.

[0042] Furthermore, the calibration is not limited to cases where the sensor value is zero, as long as the sensor value is calibrated to approach zero. Also, although the above example shows calibration performed by referring to the sensor value, calibration is not limited to referring to the sensor value. For example, an offset component may be estimated from environmental factors such as temperature and humidity, and the first resistance section 22 and the second resistance section 24 may be adjusted to suppress the offset component. Also, although the above example shows calibration performed by adjusting the first resistance section 22 and the second resistance section 24, calibration may be performed using other adjustment methods depending on the configuration of the sensor 2.

[0043] In this way, the calibration unit 34 calibrates the sensor values ​​in response to environmental factors. Furthermore, since calibration can be performed when it is determined that there are no objects around the sensor 2, sequential calibration is possible even while the robot 1 is performing its actions, and the effects of drift in the offset component due to environmental changes can be suppressed.

[0044] <Processing flow> Figure 4 is a flowchart showing an example of the processing flow by the control device 4 according to this embodiment. Each of the following steps is repeatedly executed at a predetermined control cycle during the operation of the robot 1. The order and content of each of the following steps can be changed as appropriate.

[0045] (Step SP10) The acquisition unit 30 acquires sensor values ​​from sensor 2 and monitoring results from monitoring sensor 3. Then, the process proceeds to step SP11.

[0046] (Step SP11) The determination unit 32 determines the presence or absence of objects around sensor 2 based on the monitoring results of the monitoring sensor 3. If it is determined that there are objects around sensor 2, the process proceeds to step SP12. If it is determined that there are no objects around sensor 2, the process branches to step SP15.

[0047] (Step SP12) The mode switching unit 33 selects the detection mode as the operating mode. Then, the process proceeds to step SP13.

[0048] (Step SP13) The control unit 31 determines whether the sensor value is above or below a threshold. If the sensor value is above or below the threshold, the process proceeds to step SP14. If the sensor value is below the threshold, the process ends.

[0049] (Step SP14) The control unit 31 stops the operation of robot 1, and the process ends. Note that if the control unit 31 stops the operation of robot 1, the operation of robot 1 will be resumed, for example, by a worker giving a command to resume operation.

[0050] (Step SP15) The mode switching unit 33 selects calibration mode as the operating mode. Then, the process proceeds to step SP16.

[0051] (Step SP16) The calibration unit 34 adjusts the zero point of the sensor value by having the bridge circuit 29 adjust the equilibrium state. Then the process is completed.

[0052] In this way, object detection and sensor value calibration are performed while the robot 1 is in operation. Specifically, the presence or absence of objects around sensor 2 is determined by the monitoring results of monitoring sensor 3. If there is a high probability that no objects are present, the sensor value is calibrated, and if there is a high probability that objects are present, high-precision object detection is performed using the sensor value of sensor 2.

[0053] <Effects and Effects> In this embodiment, the sensor 2 monitors the surrounding objects, and calibration of the sensor value is performed when there are no objects nearby. Therefore, the sensor value can be calibrated using the timing when there are no objects around the sensor 2. In other words, even if an offset component is generated in the sensor value due to environmental factors such as temperature and humidity, and even if the offset component drifts due to changes in environmental factors, the sensor value can still be calibrated. Furthermore, by using the timing when there are no objects around the sensor 2, calibration can be performed in conjunction with the movement of the robot 1.

[0054] Furthermore, if there are no objects around sensor 2, sensor 2 is not detecting an object, and therefore sensor 2 can be calibrated by zero-point adjustment.

[0055] Furthermore, calibration can be performed by adjusting the equilibrium state of the bridge circuit 29, which includes the detection electrode 25.

[0056] Furthermore, when the bridge circuit 29 is calibrated including the first resistor 22 and the second resistor 24, the balance state of the bridge circuit 29 can be efficiently adjusted by adjusting the resistance value of at least one of the first resistor 22 and the second resistor 24. In other words, the zero point adjustment of the sensor 2 can be performed efficiently.

[0057] Furthermore, by switching between detection mode and calibration mode based on the determination result of whether or not there are objects around sensor 2, the detection mode and calibration mode can be executed as appropriate during the operation of robot 1, thereby detecting objects and calibrating sensor 2.

[0058] ===Unique Text=== This disclosure is not limited to the embodiments described above. In other words, any design modifications made to the above-described examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. Furthermore, the elements of the above embodiments and the following modifications can be combined to the extent that it is technically possible, and any combination thereof is also included within the scope of this disclosure, as long as it retains the features of this disclosure.

[0059] For example, in the above embodiment, the case in which the sensor 2 is provided on the arm (fourth arm A4) of the robot 1 was described as an example, but the configuration of the sensor 2 in Figure 2 may be provided on the arm, or a part of the configuration may be provided on the arm. At a minimum, the detection electrode 25 that constitutes the sensor 2 is provided on the robot 1 (especially the arm).

[0060] Furthermore, while the above embodiment shows the monitoring sensor 3 being located on the upper part of the robot 1 as an example, the installation location of the monitoring sensor 3 is not limited to the above. The monitoring sensor 3 may be installed on the floor surface or other devices surrounding the robot 1, or it may be installed on the robot 1, such as an arm. In other words, the placement location of the monitoring sensor 3 is not limited as long as it can monitor objects around the sensor 2. Also, the monitoring sensor 3 may be configured using multiple sensors 2. For example, by configuring the monitoring sensor 3 using multiple cameras installed at different locations, the monitoring of objects around the sensor 2 can be performed more accurately. In addition, the monitoring sensor 3 may be fixed, with a predetermined area to be imaged, or it may be movable, with the area to be imaged moving according to the posture of the robot 1 and the position of the sensor 2.

[0061] Furthermore, although the above embodiment uses the example of a robot 1 equipped with one sensor 2, the robot 1 may be equipped with multiple sensors 2. In this case, the control device 4 calibrates each sensor 2 individually. Alternatively, one monitoring sensor 3 may monitor objects around multiple sensors 2.

[0062] Furthermore, in the above embodiment, the determination unit 32 was described as determining that there are objects around the sensor 2 if the image showing the surrounding conditions of the captured sensor 2 indicates that there are objects around the sensor 2, but the invention is not limited to this. For example, even if the image showing the surrounding conditions of the captured sensor 2 does not indicate that there are no objects around the sensor 2, the determination unit 32 may determine that there are objects around the sensor 2. In other words, if it is not certain that there are no objects around the sensor 2 due to the influence of obstacles or the like, the determination unit 32 may determine that there are objects around the sensor 2.

[0063] Furthermore, in the above embodiment, one example was given where the control unit 31 does not perform stop control of the robot 1's operation using sensor values ​​in calibration mode. However, stop control using sensor values ​​by the control unit 31 may be performed in calibration mode.

[0064] Furthermore, in the above embodiment, a case was described in which the calibration unit 34 adjusts the equilibrium state of the bridge circuit 29 to calibrate the sensor value when it is determined that there are no objects around the sensor 2. The calibration method is not limited to the above. For example, the sensor value when it is determined that there are no objects around the sensor 2 may be set as a calibration correction value, and the sensor value may be calibrated. In this case, the calibration unit 34 sets the sensor value when it is determined that there are no objects around the sensor 2 as the calibration correction value. That is, the calibration correction value indicates the offset component of the sensor value due to environmental factors. The set calibration correction value is used, for example, in the control unit 31. For example, the control unit 31 processes the sensor value obtained from the sensor 2 and removes the set calibration correction value, and compares the processed sensor value with a threshold to determine whether or not an object is in close proximity to the robot 1. The process of removing the calibration correction value from the sensor value is, for example, the process of subtracting the calibration correction value from the sensor value. As a result, the control unit 31 uses the sensor value with the offset component suppressed to control the stopping of the robot 1. Thus, the calibration unit 34 may perform calibration of the sensor value by setting a calibration correction value when it is determined that there are no objects around the sensor 2. [Explanation of symbols]

[0065] 1: Robot 2: Sensor 3: Surveillance Sensors 4: Control device 10: Robot System 22: 1st resistance section 24: 2nd resistance section 25: Detection electrode 29: Bridge Circuit H: Person (object)

Claims

1. Robots and, A sensor provided on the robot that outputs a sensor value corresponding to the capacitance generated between it and an object, A monitoring sensor that monitors objects around the aforementioned sensor, A control device that determines the presence or absence of objects around the sensor based on the monitoring results of the aforementioned monitoring sensor, and performs calibration of the sensor value when it is determined that there are no objects around the sensor, A robot system characterized by having the following features.

2. The robot system according to claim 1, characterized in that the control device performs zero-point adjustment of the sensor value when it is determined that there are no objects around the sensor.

3. The sensor has a bridge circuit including a detection electrode that generates an electric field in a predetermined direction. The robot system according to claim 1 or 2, characterized in that the control device adjusts the balance state of the bridge circuit and performs calibration for the sensor value.

4. The bridge circuit includes a first resistor and a second resistor. The robot system according to claim 3, characterized in that the control device adjusts the resistance value of at least one of the first resistor and the second resistor to perform zero-point adjustment of the sensor value.

5. The robot system according to claim 1 or 2, characterized in that the control device switches between a detection mode, in which object detection is performed using the sensor value, and a calibration mode, in which the sensor value is calibrated, based on the result of determining whether or not there is an object around the sensor.

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