JP7009549B2 - Capacitive proximity detection device with safety function - Google Patents

Description

The present invention relates to a capacitance type proximity detection device having a safety function.

Patent Document 1 describes that a human collaborative robot is provided with a proximity sensor to detect the distance between the robot and a human. Examples of proximity sensors include ultrasonic sensors, optical sensors, capacitance sensors, and radio wave sensors.

International Publication No. 2018/131237

High safety is required for human collaborative robots and the like. Therefore, it is required to accurately grasp the distance between the robot and the human. Then, in order to increase the safety of the detection device, it is conceivable to perform detection in a plurality of systems. That is, each of the first system and the second system is provided with a sensor electrode and a detection circuit.

Since the person to be detected is the same target in both the first system and the second system, the sensor electrode of the first system and the sensor electrode of the second system are installed close to each other. In this case, if the excitation voltage is applied to the sensor electrode of the first system and the sensor electrode of the second system at the same timing, they interfere with each other, so that the capacitance between each sensor electrode and the detection target is increased. It cannot be detected with high accuracy.

By applying excitation voltages to the sensor electrodes of the first system and the sensor electrodes of the second system at different timings, it is possible to solve the problem of mutual interference. However, the sensor electrodes of the first system and the sensor electrodes of the second system may form a pair of electrodes of a so-called capacitor. Therefore, when an excitation voltage is applied to one sensor electrode, the charge may move from one sensor electrode to the other sensor electrode. As a result, the capacitance between the sensor electrode and the detection target cannot be detected with high accuracy.

As described above, when a plurality of systems are configured to have a safety function, it is not easy to detect the capacitance with the detection target with high accuracy. An object of the present invention is to provide a capacitance type proximity detection device having a safety function capable of detecting a capacitance with a detection target with high accuracy while having a plurality of systems as a safety function. do.

The capacitive proximity detection device having the safety function according to the present invention is a switch for switching between one sensor electrode for detecting the proximity of a detection target and one of a plurality of systems so as to be connected to the sensor electrode. And, the first system of the plurality of systems is configured, the first signal detected by the sensor electrode is acquired in the state of being connected to the sensor electrode by the switch, and the sensor is based on the first signal. A first system detection circuit that detects the first capacitance between the electrode and the detection target, and a first system that performs processing on the target device based on the first capacitance detected by the first system detection circuit. A second system detected by the sensor electrode at a timing different from that of the first signal in a state where the one system processing device and the second system of the plurality of systems are configured and connected to the sensor electrode by the switch . A second system detection circuit that acquires a signal and detects a second capacitance between the sensor electrode and the detection target based on the second signal, and the first system detection circuit detected by the second system detection circuit. (Ii) Timing at which the second system processing device that performs processing on the target device based on the capacitance and the first capacitance and the second capacitance become the same value when the sensor electrode is normal. The difference between the first capacitance detected by the first system detection circuit and the second capacitance detected by the second system detection circuit , or the first capacitance and the second capacitance . A diagnostic circuit for diagnosing the sensor electrode is provided based on the comparison result between each of the capacities and the reference capacitance .

In the capacitance type proximity detection device according to the present invention, the first system is configured by the first system detection circuit and the first system processing device, and the second system is configured by the second system detection circuit and the second system processing device. .. The sensor electrodes are shared between the first system and the second system. By sharing the sensor electrodes, it is possible to prevent the excitation voltages from interfering with each other and from transferring charges to other sensor electrodes. Therefore, the capacitance between the sensor electrode and the detection target can be detected with high accuracy.

Further, although the sensor electrodes are shared, the detection circuit and the processing device are independent in the first system and the second system. Therefore, it has high safety. Further, the capacitance type proximity detection device includes a diagnostic circuit. The diagnostic circuit diagnoses the sensor electrode based on the first capacitance detected by the first system detection circuit and the second capacitance detected by the second system detection circuit. Therefore, the abnormality of the sensor electrode can be detected, and high safety can be ensured.

It is a figure which shows the application example of the capacitance type proximity detection apparatus. It is a block diagram of the capacitance type proximity detection apparatus of 1st example. It is a time chart of the processing of the first system and the processing of the second system in the first example. It is a flowchart which shows the 1st diagnostic process by a diagnostic circuit. It is a flowchart which shows the 2nd diagnostic process by a diagnostic circuit. It is a block diagram of the capacitance type proximity detection apparatus of the 2nd example. It is a time chart of the processing of the first system and the processing of the second system in the second example. It is a block diagram of the capacitance type proximity detection apparatus of the 3rd example. It is a time chart of the processing of the first system and the processing of the second system in the third example. It is a block diagram of the capacitance type proximity detection apparatus of the 4th example. It is a time chart of the processing of the first system and the processing of the second system in the fourth example. It is a figure which shows the application example of the standard device of 1st example, and shows the capacitance before correction. It is a figure which shows the application example of the standard device of 1st example, and shows the capacitance after correction. It is a figure which shows the application example of the standard | standard of 1st example, and shows the mode of the detection of the proximity of the detection object using the corrected capacitance. It is a figure which shows the application example of the standard device of 1st example, and shows the diagnosis using the corrected capacitance. It is a flowchart which shows the 1st diagnosis using the standard | standard of 1st example. It is a flowchart which shows the 2nd diagnosis using the standard | standard of 1st example. It is a figure which shows the application example of the standard device of 2nd example, and shows each capacitance. It is a figure which shows the application example of the standard | standard of the 2nd example, and shows the mode of the detection of the proximity of the detection target in the environment S1. It is a figure which shows the application example of the standard device of 2nd example, and shows the mode of the detection of the proximity of the detection target in the environment S2. It is a figure which shows the application example of the standard device of 2nd example, and shows each capacitance at the time of diagnosing a sensor electrode. It is a figure which shows the application example of the standard device of 2nd example, and shows the diagnosis in the environment S1. It is a flowchart which shows the 1st diagnosis using the standard | standard of 2nd example. It is a flowchart which shows the 2nd diagnosis using the standard of 2nd example.

(1. Application example of capacitance type proximity detection device 1)
An application example of the capacitance type proximity detection device 1 (hereinafter referred to as “detection device”) will be described with reference to FIG. The detection device 1 can be applied, for example, as a device arranged in the human collaborative robot 2 and detecting that a person, which is an example of the detection target 3, is close to the human collaborative robot 2. Then, when it is determined that the person who is the detection target 3 is close to the human collaborative robot 2 within a predetermined distance, the human collaborative robot 2 may be stopped or a warning may be issued. can.

Here, the predetermined distance between the human collaborative robot 2 and the detection target 3 is extremely far compared to the distance between the touch panel and the human finger. Therefore, the capacitance Cx between the target human collaborative robot 2 and the detection target 3 is very small. That is, the detection device 1 is a device that can detect the proximity of a person who is the detection target 3 based on an extremely small change in capacitance Cx.

Further, the detection target 3 of the detection device 1 can target all conductors in addition to humans. For example, the detection target 3 of the detection device 1 can be a robot, the installation target of the detection device 1 can be another robot, and the detection device 1 can be applied as a device for detecting the proximity of robots to each other.

Further, the target for installing the detection device 1 can be installed at an arbitrary position in addition to the human collaborative robot 2. For example, by installing the detection device 1 in a human intrusion prohibited area, which is the detection target 3, it is possible to detect the intrusion of a person.

The human collaborative robot 2 shown in FIG. 1 is a serial link type robot for performing arbitrary work. The human collaborative robot 2 has a plurality of joints and is provided with a work unit at the tip. For example, the human collaborative robot 2 is a robot that conveys an object to be conveyed (not shown), and has a hand that grips the object to be conveyed at its tip. However, the human collaborative robot 2 is not limited to the above configuration, and may have any configuration.

As shown in FIG. 1, the detection device 1 includes a sensor main body 10 and a circuit unit 20. The sensor body 10 is installed on the surface of the human collaborative robot 2. For example, the sensor body 10 is installed near the work unit (near the tip) of the human collaborative robot 2. The sensor body 10 can be a frame formed by painting or plating on a frame constituting the outer peripheral portion of the cylinder of the human collaborative robot 2, or a frame itself formed of a conductor such as metal. It should be noted that the member may be formed separately from the frame body and may be attached to the frame body. The circuit unit 20 is electrically connected to the sensor main body 10 and acquires the capacitance Cx. The circuit unit 20 acquires an equivalent value of the capacitance Cx by, for example, applying an excitation voltage to the sensor main body 10 and detecting a current flowing when the excitation voltage is applied.

(2. Capacitance type proximity detection device 1 of the first example)
(2-1. Configuration of detection device 1)
The configuration of the detection device 1 of the first example will be described with reference to FIG. The detection device 1 includes a sensor main body 10 and a circuit unit 20. The sensor body 10 includes one sensor electrode 11 and one ground electrode 12.

The sensor electrode 11 is formed in a planar shape (including a flat surface and a curved surface), and is an electrode for detecting the proximity of the detection target 3 (for example, a person). An insulating layer (not shown) is provided on the surface of the sensor electrode 11, that is, the surface on the side of the detection target 3. Capacitance Cx between the sensor electrode 11 and the detection target 3.

The ground electrode 12 is formed in a shape capable of facing the sensor electrode 11 at a distance from the sensor electrode 11, and is arranged on the opposite side of the sensor electrode 11 from the detection target 3. For example, when the ground electrode 12 is formed in a planar shape, the ground electrode 12 is formed to have the same size as the sensor electrode 11. Further, when the sensor electrode 11 is formed in a cylindrical shape, the ground electrode 12 can also be a core material constituting the central axis of the cylinder. The ground electrode 12 is grounded. An insulating layer (not shown) is provided between the sensor electrode 11 and the ground electrode 12.

The sensor body 10 may have an active guard electrode (also referred to as a shield electrode) arranged between the sensor electrode 11 and the ground electrode 12. In this case, by applying the same excitation voltage as the sensor electrode 11 to the active guard electrode, the parasitic capacitance between the sensor electrode 11 and the ground electrode 12 can be regarded as 0 (zero). Therefore, the movement of the electric charge in the sensor electrode 11 is affected only by the detection target 3, and the proximity of the detection target can be detected with high accuracy.

The circuit unit 20 includes a first system detection circuit 21, a first system processing device 22, a second system detection circuit 23, a second system processing device 24, a switch 25, and a diagnostic circuit 26. Here, the first system detection circuit 21 and the first system processing device 22 form the first system among the plurality of systems. The second system detection circuit 23 and the second system processing device 24 form the second system of the plurality of systems. As described above, the detection device 1 has a configuration having a safety function by having a plurality of systems.

The first system detection circuit 21 acquires the first signal detected by the sensor electrode 11 in a state of being connected to the sensor electrode 11. For example, the first system detection circuit 21 applies a rectangular excitation voltage to the sensor electrode 11, and acquires the current flowing through the sensor electrode 11 as the first signal when the excitation voltage is applied. Then, the first system detection circuit 21 detects the first capacitance Cx1 between the sensor electrode 11 and the detection target 3 based on the first signal. The first capacitance Cx1 is the capacitance Cx in the first system.

The first system processing device 22 performs processing on the target device based on the first capacitance Cx1 detected by the first system detection circuit 21. For example, when the first capacitance Cx1 is the capacitance Cx corresponding to the proximity of the person who is the detection target 3 within a predetermined distance from the human collaborative robot 2, the first system processing device 22 may be used. A signal for stopping the operation of the human collaborative robot 2 or issuing a warning sound is output to the target device.

Here, the target device is, for example, an actuator for driving a joint in the human collaborative robot 2, a speaker device for emitting a warning sound, a display device for displaying a state, and the like. Then, the first system processing device 22 outputs a drive signal for performing a predetermined drive to the actuator, outputs a drive signal for issuing a warning sound to the speaker device, and outputs a drive signal to the display device. Outputs a signal to display the status.

The second system detection circuit 23 can be connected to the sensor electrode 11 to which the first system detection circuit 21 is connected. The second system detection circuit 23 operates independently of the first system detection circuit 21. The second system detection circuit 23 acquires the second signal detected by the sensor electrode 11 at a timing different from that of the first signal in the state of being connected to the sensor electrode 11.

For example, the second system detection circuit 23 applies a rectangular excitation voltage to the sensor electrode 11 at a timing different from that of the first system detection circuit 21, and transfers the current flowing through the sensor electrode 11 when the excitation voltage is applied. Acquire as a signal. Then, the second system detection circuit 23 detects the second capacitance Cx2 between the sensor electrode 11 and the detection target 3 based on the second signal. The second capacitance Cx2 is the capacitance Cx in the second system.

The second system processing device 24 performs processing on the target device based on the second capacitance Cx2 detected by the second system detection circuit 23. The processing by the second system processing device 24 is substantially the same as the processing by the first system processing device 22, except that the timing is different.

The switch 25 sequentially switches the system connected to the sensor electrode 11 among the plurality of systems. Specifically, the switch 25 switches between the a side connecting the sensor electrode 11 and the first system detection circuit 21 and the b side connecting the sensor electrode 11 and the second system detection circuit 23. That is, the detection circuit connected to the sensor electrode 11 is either the first system detection circuit 21 or the second system detection circuit 23, and both are not connected at the same time. Therefore, the timing at which the first system detection circuit 21 and the second system detection circuit 23 are connected to the sensor electrode 11 is different.

Here, the first system detection circuit 21 is connected to the sensor electrode 11 when the switch 25 is on the a side, and acquires the first signal detected by the sensor electrode 11 in that state. However, the first system detection circuit 21 can acquire the first signal at an arbitrary timing while being connected to the sensor electrode 11. Therefore, in FIG. 3, the time when the first system detection circuit 21 acquires the first signal is a part of the time when the switch 25 is connected to the a side.

Further, the second system detection circuit 23 is connected to the sensor electrode 11 when the switch 25 is on the b side, and acquires the second signal detected by the sensor electrode 11 in that state. However, the second system detection circuit 23 can acquire the second signal at an arbitrary timing while being connected to the sensor electrode 11. Therefore, in FIG. 3, the time when the second system detection circuit 23 acquires the first signal is a part of the time when the switch 25 is connected to the b side.

The diagnostic circuit 26 diagnoses the sensor electrode 11 based on the first capacitance Cx1 detected by the first system detection circuit 21 and the second capacitance Cx2 detected by the second system detection circuit 23. The diagnostic circuit 26 performs an internal diagnosis of the first system detection circuit 21. The diagnostic circuit 26 also performs an internal diagnosis of the second system detection circuit 23.

Here, when the sensor electrode 11, the first system detection circuit 21, and the second system detection circuit 23 are normal, the first capacitance Cx1 and the second capacitance Cx2 have the same value. On the other hand, if the sensor electrode 11 is normal when the first system detection circuit 21 acquires the first signal, and then the sensor electrode 11 becomes abnormal when the second system detection circuit 23 acquires the second signal. The first capacitance Cx1 and the second capacitance Cx2 have different values. That is, the diagnostic circuit 26 diagnoses the sensor electrode 11 as abnormal when the first capacitance Cx1 and the second capacitance Cx2 are different.

For example, the diagnostic circuit 26 determines that the sensor electrode 11 is abnormal when the difference between the first capacitance Cx1 and the second capacitance Cx2 is larger than a predetermined value. Here, the first capacitance Cx1 corresponds to the magnitude of the first signal, and the second capacitance Cx2 corresponds to the magnitude of the second signal. Therefore, the diagnostic circuit 26 may determine the abnormality of the sensor electrode 11 when the difference between the first signal and the second signal is larger than a predetermined value.

However, even before and after the proximity of the person who is the detection target 3, the first capacitance Cx1 and the second capacitance Cx2 have different values. Therefore, by grasping in advance the change in capacitance due to the proximity of a person, it is possible to distinguish between the abnormality of the sensor electrode 11 and the proximity of the person who is the detection target 3.

Further, even when one of the first system detection circuit 21 and the second system detection circuit 23 is normal and the other is abnormal, the values of the first capacitance Cx1 and the second capacitance Cx2 are different. In this case, even if time elapses, the values of the first capacitance Cx1 and the second capacitance Cx2 remain different. Therefore, in the diagnostic circuit 26, the first capacitance Cx1 and the second capacitance Cx2 continuously have different values, so that one of the first system detection circuit 21 and the second system detection circuit 23 is abnormal. Can be diagnosed.

As described above, the diagnostic circuit 26 can distinguish between the proximity of the person who is the detection target 3 and the abnormality of the sensor electrode 11. However, it is also possible for the diagnostic circuit 26 to diagnose that both are in an abnormal state without distinguishing between the two, and to stop the human collaborative robot 2 by the first system processing device 22 or the second system processing device 24. Is.

(2-2. Operation of detection device 1)
The operation of the detection device 1 will be described with reference to FIGS. 3 to 5. When the switch 25 is connected to the a side, the sensor electrode 11 is connected to the first system detection circuit 21. By doing so, as shown in FIG. 3, the first system detection circuit 21 detects the first capacitance Cx1 (S1a). While the switch 25 is connected to the a side, the diagnostic circuit 26 can perform the second diagnosis using the first capacitance Cx1 detected by the first system detection circuit 21 in S1a this time. Further, while the switch 25 is connected to the a side, the diagnostic circuit 26 makes a second diagnosis using the previously detected second capacitance Cx2 (S2b).

Subsequently, when the switch 25 is switched to the b side, the second system detection circuit 23 is connected to the sensor electrode 11 and detects the second capacitance Cx2 (S2a). While the switch 25 is connected to the b side, the diagnostic circuit 26 can perform the second diagnosis using the second capacitance Cx2 detected by the second system detection circuit 23 in S2a this time. Further, while the switch 25 is connected to the b side, the diagnostic circuit 26 makes a first diagnosis using the first capacitance Cx1 detected in S1a (S1b).

As shown in FIG. 4, the first diagnosis in the diagnostic circuit 26 is an internal diagnosis of the first system detection circuit 21 (S1). Subsequently, the diagnostic circuit 26 diagnoses the sensor electrode 11 by comparing the first capacitance Cx1 detected this time with the second capacitance Cx2 already detected (S2). Then, the first diagnosis is completed. However, the diagnostic circuit 26 can also reverse the order of the internal diagnosis and the comparative diagnosis.

As shown in FIG. 5, the second diagnosis in the diagnostic circuit 26 is an internal diagnosis of the second system detection circuit 23 (S3). Subsequently, the diagnostic circuit 26 diagnoses the sensor electrode 11 by comparing the second capacitance Cx2 detected this time with the first capacitance Cx1 already detected (S4). Then, the second diagnosis is completed. However, the diagnostic circuit 26 can also reverse the order of the internal diagnosis and the comparative diagnosis.

Here, the diagnostic circuit 26 has been described as having a different configuration from the first system detection circuit 21 and the second system detection circuit 23. Not limited to this, some functions of the diagnostic circuit 26 may be incorporated in the first system detection circuit 21, and some other functions may be incorporated in the second system detection circuit 23. good.

(2-3. Effect)
The detection device 1 constitutes the first system by the first system detection circuit 21 and the first system processing device 22, and constitutes the second system by the second system detection circuit 23 and the second system processing device 24. The sensor electrode 11 is shared between the first system and the second system. By sharing the sensor electrode 11, it is possible to prevent the excitation voltages from interfering with each other and the electric charge from being transferred to other sensor electrodes. Therefore, the capacitance Cx between the sensor electrode 11 and the detection target 3 can be detected with high accuracy.

In particular, by using the switch 25, when the sensor electrode 11 and the first system detection circuit 21 are connected, the sensor electrode 11 and the second system detection circuit 23 can be in a non-connected state. And vice versa. Therefore, by controlling the operation of the switch 25 as described above, it is possible to prevent the electric charge in the sensor electrode 11 from moving to the system on the side where it is not detected. That is, when the first system detection circuit 21 acquires the first signal from the sensor electrode 11, it is possible to prevent the charge of the sensor electrode 11 from moving to the second system detection circuit 23. And vice versa.

Further, although the sensor electrode 11 is shared, the detection circuits 21 and 23 and the processing devices 22 and 24 are independent in the first system and the second system. Therefore, it has high safety. Further, the detection device 1 includes a diagnostic circuit 26. The diagnostic circuit 26 diagnoses the sensor electrode 11 based on the first capacitance Cx1 detected by the first system detection circuit 21 and the second capacitance Cx2 detected by the second system detection circuit 23. Therefore, the abnormality of the sensor electrode 11 can be detected, and high safety can be ensured.

Further, at least a part of the first diagnosis by the diagnostic circuit 26 is performed when the second system detection circuit 23 is connected to the sensor electrode 11. As described above, when the second system detection circuit 23 is connected to the sensor electrode 11, the first system detection circuit 21 is not connected to the sensor electrode 11, so that the first signal is acquired from the sensor electrode 11. Can't. Therefore, in order to make effective use of the time, the diagnostic circuit 26 decides to perform the first diagnosis at the time. Further, at least a part of the second diagnosis by the diagnostic circuit 26 is performed when the first system detection circuit 21 is connected to the sensor electrode 11. In this case as well, the time can be effectively used.

(3. Capacitance type proximity detection device 1a of the second example)
(3-1. Configuration of the detection device 1a of the second example)
The configuration of the detection device 1a of the second example will be described with reference to FIG. The detection device 1a of the second example differs from the detection device 1 of the first example only by the switch 25.

The switch 25 sequentially switches the system connected to the sensor electrode 11 among the plurality of systems. Specifically, the switch 25 is an ON / OFF of the connection between the first switch 25a for switching ON / OFF of the connection between the sensor electrode 11 and the first system detection circuit 21 and the connection between the sensor electrode 11 and the second system detection circuit 23. It is provided with a second switch 25b for switching OFF.

When the first switch 25a is ON, the second switch 25b is OFF. When the second switch 25b is ON, the first switch 25a is OFF. That is, the first switch 25a and the second switch 25b are not turned on at the same time. Therefore, the timing at which the first switch 25a is turned on and the timing at which the second switch 25b is turned on are different.

Here, the first system detection circuit 21 is connected to the sensor electrode 11 when the first switch 25a is ON, and acquires the first signal detected by the sensor electrode 11 in that state. Further, the second system detection circuit 23 is connected to the sensor electrode 11 when the second switch 25b is ON, and acquires the second signal detected by the sensor electrode 11 in that state.

(3-2. Operation of the detection device 1a of the second example)
The operation of the detection device 1a of the second example will be described with reference to FIG. 7. The first switch 25a is turned on, and the sensor electrode 11 is connected to the first system detection circuit 21. By doing so, the first system detection circuit 21 detects the first capacitance Cx1 (S1a). During this time, the second switch 25b is turned off, and the diagnostic circuit 26 performs diagnostic processing (S2b).

Subsequently, the first switch 25a is turned off and the second switch 25b is turned on. By doing so, the second system detection circuit 23 is connected to the sensor electrode 11 and detects the second capacitance Cx2 (S2a). During this time, the diagnostic circuit 26 makes the first diagnosis using the first capacitance Cx1 detected in S1a (S1b).

Subsequently, in the second system, the second switch 25b is turned off, so that the first switch 25a and the second switch 25b are turned off. At this time, the diagnostic circuit 26 continues the first diagnosis in the first system. On the other hand, the diagnostic circuit 26 performs the second diagnosis in the second system.

(4. Capacitance type proximity detection device 4 of the third example)
(4-1. Configuration of the detection device 4 of the third example)
The configuration of the detection device 4 of the third example will be described with reference to FIG. The detection device 4 includes a sensor main body 10, a circuit unit 30, and an external device 40. In the detection device 4 of the third example, the same components as those of the detection device 1 of the first example are designated by the same reference numerals and the description thereof will be omitted.

The circuit unit 30 includes a first system detection circuit 21, a first system processing device 22, a second system detection circuit 23, a second system processing device 24, a communication device 31, a switch 32, and a diagnostic circuit 33. The first system detection circuit 21, the first system processing device 22, the second system detection circuit 23, and the second system processing device 24 are the same as those in the first example.

The communication device 31 communicates with the external device 40. Here, the external device 40 can be a host computer, a control device for the human collaborative robot 2, peripheral sensors such as a light curtain, a reference device for diagnosis in the diagnostic circuit 33, and the like. The external device 40 with which the communication device 31 can communicate can be set to one or a plurality depending on the purpose.

The switch 32 includes a first switch 32a and a second switch 32b. The first switch 32a switches between a state in which the sensor electrode 11 and the first system detection circuit 21 are connected and a state in which the first system detection circuit 21 and the communication device 31 as a separate device are connected. The second switch 32b switches between a state in which the sensor electrode 11 and the second system detection circuit 23 are connected and a state in which the second system detection circuit 23 and the communication device 31 as a separate device are connected.

Here, in the state where the first switch 32a connects the sensor electrode 11 and the first system detection circuit 21, the second switch 32b is in the state where the sensor electrode 11 and the second system detection circuit 23 are connected. It doesn't become. The reverse is also true.

That is, the switch 32 connects the sensor electrode 11 and the first system detection circuit 21, and also connects the second system detection circuit 23 and the communication device 31 as a separate device, and the sensor electrode 11 and the second system. The state of connecting the detection circuit 23 and connecting the first system detection circuit 21 and the communication device 31 as a separate device is switched.

Similar to the first example, the diagnostic circuit 33 is a sensor based on the first capacitance Cx1 detected by the first system detection circuit 21 and the second capacitance Cx2 detected by the second system detection circuit 23. The electrode 11 is diagnosed. In this diagnosis, the sensor electrode 11 and the first system detection circuit 21 are connected by the first switch 32a, or the sensor electrode 11 and the second system detection circuit 23 are connected by the second switch 32b. It is done in the meantime.

Further, the diagnostic circuit 33 acquires information from the communication device 31 and obtains information from the communication device 31 while the sensor electrode 11 and the first system detection circuit 21 are connected by the first switch 32a. The sensor electrode 11 is diagnosed using the sensor electrode 11. For example, in the diagnostic circuit 33, the diagnosis of the sensor electrode 11 in the above is performed in consideration of the information acquired from the host computer, the control state of the human collaborative robot 2, the peripheral sensor information, and the like as the information acquired from the communication device 31. Will be done.

Further, the diagnostic circuit 33 acquires information from the communication device 31 and acquires information from the communication device 31 while the sensor electrode 11 and the second system detection circuit 23 are connected by the second switch 32b. The sensor electrode 11 is diagnosed using the sensor electrode 11.

(4-2. Operation of detection device 4)
The operation of the detection device 4 will be described with reference to FIG. The first switch 32a is connected to the a side to connect the sensor electrode 11 and the first system detection circuit 21. By doing so, the first system detection circuit 21 detects the first capacitance Cx1 (S11a). During this time, the second switch 32b is connected to the b side to connect the communication device 31 and the second system detection circuit 23.

Subsequently, the first switch 32a is connected to the b side, and the second switch 32b is connected to the a side. By doing so, the second system detection circuit 23 is connected to the sensor electrode 11 and detects the second capacitance Cx2. At this time, the first system detection circuit 21 is connected to the communication device 31 to acquire information from the communication device 31 (S11b). After that, the diagnostic circuit 33 performs the first diagnosis using the information acquired from the communication device 31 in the first capacitance Cx1 detected in S11a, the second capacitance Cx2 previously detected, and S11b (S11c).

In the second system, after the second system detection circuit 23 detects the second capacitance Cx2, the second switch 32b is switched to the b side. The second system detection circuit 23 acquires information from the communication device 31 by being connected to the communication device 31 (S12b). After that, the diagnostic circuit 33 performs the second diagnosis using the information acquired from the communication device 31 in the first capacitance Cx1 detected in S11a, the second capacitance Cx2 detected in S12a, and S12b (S12c).

In the third example, the switch 32 switches between the state of being connected to the sensor electrode 11 and the state of being connected to the communication device 31. Therefore, the first system detection circuit 21 can acquire the information of the external device 40 via the communication device 31 and can perform the first diagnosis in a state where the first system detection circuit 21 is not connected to the sensor electrode 11.

Then, in a state where the first system detection circuit 21 is connected to the communication device 31 and a state where the diagnostic circuit 33 is performing the first diagnosis, the second system detection circuit 23 is connected to the sensor electrode 11. The second capacitance Cx2 is detected. Therefore, while the second capacitance Cx2 is being detected, information is acquired from the communication device 31 and the first diagnosis is performed. As a result, time can be effectively used.

(5. Capacitance type proximity detection device 5 of the fourth example)
(5-1. Configuration of the detection device 5 of the fourth example)
The configuration of the detection device 5 of the fourth example will be described with reference to FIG. The detection device 5 includes a sensor body 10 and a circuit unit 50. In the detection device 5 of the fourth example, the same components as those of the first example are designated by the same reference numerals and the description thereof will be omitted.

The circuit unit 50 includes a first system detection circuit 21, a first system processing device 22, a second system detection circuit 23, a second system processing device 24, a reference device 51 as a separate device, a switch 52, and a diagnostic circuit 53. The first system detection circuit 21, the first system processing device 22, the second system detection circuit 23, and the second system processing device 24 are the same as those in the first example. It is also possible to replace the external device 40 in the third example with the reference device 51 in this example.

The reference device 51 can output a reference signal of the sensor electrode 11 in a reference state that is not affected by the proximity of the detection target 3. The reference signal is used in the first system detection circuit 21 and the second system detection circuit 23 to determine the proximity of the detection target 3 using the capacitance Cx. Further, the reference signal is used in the diagnosis of the sensor electrode 11 by comparing with the first capacitance Cx1 or the second capacitance Cx2 in the diagnostic circuit 53.

The reference signal may have the same value as the signal output by the sensor electrode 11 in the reference state, or may have a different value from the signal output by the sensor electrode 11 and has a correlation with the signal output by the sensor electrode 11. It may be a value.

The switch 52 includes a first switch 52a and a second switch 52b. The first switch 52a switches between a state in which the sensor electrode 11 and the first system detection circuit 21 are connected and a state in which the first system detection circuit 21 and the reference device 51 as a separate device are connected. The second switch 52b switches between a state in which the sensor electrode 11 and the second system detection circuit 23 are connected and a state in which the second system detection circuit 23 and the reference device 51 as a separate device are connected.

Here, in the state where the first switch 52a connects the sensor electrode 11 and the first system detection circuit 21, the second switch 52b is in the state where the sensor electrode 11 and the second system detection circuit 23 are connected. It doesn't become. The reverse is also true.

That is, the switch 52 connects the sensor electrode 11 and the first system detection circuit 21, and also connects the second system detection circuit 23 and the reference device 51 as a separate device, and the sensor electrode 11 and the second system. The state of connecting the detection circuit 23 and connecting the first system detection circuit 21 and the reference device 51 as a separate device is switched.

The diagnostic circuit 53 diagnoses the sensor electrode 11 by comparing the first capacitance Cx1 detected by the first system detection circuit 21 with the reference signal acquired from the reference device 51. This diagnosis is performed while the sensor electrode 11 and the second system detection circuit 23 are connected. Further, the diagnostic circuit 53 diagnoses the sensor electrode 11 by comparing the second capacitance Cx2 detected by the second system detection circuit 23 with the reference signal acquired from the reference device 51. This diagnosis is performed while the sensor electrode 11 and the first system detection circuit 21 are connected.

Further, the diagnostic circuit 53 compares the first capacitance Cx1 detected by the first system detection circuit 21 with the second capacitance Cx2 detected by the second system detection circuit 23, as in the first example. Therefore, the sensor electrode 11, the first system detection circuit 21, and the second system detection circuit 23 can be diagnosed.

(5-2. Operation of the detection device 5 in the fourth example)
The operation of the detection device 5 of the fourth example will be described with reference to FIG. The operation of the detection device 5 in this example is the same as the operation of the detection device 4 in the third example. However, in the fourth example, the acquisition of information from the communication device 31 in the third example is replaced with the acquisition of the reference signal from the reference device 51.

Then, in the first diagnosis, the sensor electrode 11 is diagnosed by comparing the first capacitance Cx1 with the reference signal (S11c). The first diagnosis is performed when the second system detection circuit 23 detects the second capacitance Cx2. Further, in the second diagnosis, the sensor electrode 11 is diagnosed by comparing the second capacitance Cx2 with the reference signal (S12c). The second diagnosis is performed when the second system detection circuit 23 detects the second capacitance Cx2. Further, the first diagnosis and the second diagnosis may be performed at the same timing.

(5-3. Modification of the fourth example)
In the detection device 5 of the fourth example described above, it is assumed that the reference device 51 can output a reference signal to the first system detection circuit 21 and the second system detection circuit 23 via the switch 52. However, the detection device 5 does not have the switch 52, and the reference device 51 can directly output the reference signal to the first system detection circuit 21 and the second system detection circuit 23 without going through the switch 52. May be good.

(6. Application example of standard device 51)
(6-1. Reference device 51 of the first example)
In the detection device 5 of the fourth example and its modification, the reference device 51 stores the reference signal of the sensor electrode 11 in the reference state which is not affected by the proximity of the detection target 3, and can output the reference signal. ..

The reference device 51 of the first example will be described with reference to FIGS. 12 to 17. The reference device 51 is a capacitor having a fixed capacitance. This capacitor is housed in a housing so as not to be affected by the external environment. Therefore, the reference signal Cth output by the reference device 51 does not have environment dependence. That is, the reference signal Cth does not depend on the ambient temperature or humidity. As shown in FIG. 12, the reference signal Cth of the reference device 51 is a constant value with respect to changes in the environment.

On the other hand, the capacitance Cx between the sensor electrode 11 and the detection target 3 is environment-dependent. Therefore, the first capacitance Cx1 and the second capacitance Cx2 are environment-dependent. As shown in FIG. 12, when the detection target 3 is not in close proximity, the capacitance C0 obtained from the output signal of the sensor electrode 11 changes with the change in the environment. Similarly, when the detection target 3 is in close proximity, the capacitance C1 obtained from the output signal of the sensor electrode 11 also changes with the change in the environment.

For example, in the environment S, when there is no abnormality in the sensor electrode 11 and the detection target 3 is not in close proximity, the difference between the reference signal Cth and the detected capacitance C0 is ΔC0. In the environment S, when there is no abnormality in the sensor electrode 11 and the detection target 3 is close to each other, the difference between the reference signal Cth and the detected capacitance C1 becomes ΔC1. However, if the environment S changes, ΔC0 and ΔC1 change.

Therefore, as shown in FIG. 13, the detected capacitance is corrected in order to make the state independent of the environment. When there is no abnormality in the sensor electrode 11 and the detection target 3 is not in close proximity, the detected capacitance is C0a. When there is no abnormality in the sensor electrode 11 and the detection target 3 is close to the sensor electrode 11, the detected capacitance is C1a.

Before and after the person who is the detection target 3 is in close proximity, the corrected capacitance is as shown in FIG. The corrected capacitance is C0a before proximity and C1a after proximity. Therefore, the first system detection circuit 21 detects the proximity of the detection target 3 in consideration of the correction value due to the environment dependence in the comparison between the first capacitance Cx1 and the reference signal Cth. Further, the second system detection circuit 23 detects the proximity of the detection target in consideration of the correction value due to the environment dependence in the comparison between the second capacitance Cx2 and the reference signal Cth. As a result, the determination can be made with higher accuracy.

Further, as shown in FIG. 15, the diagnostic circuit 53 diagnoses the sensor electrode 11 by comparing the corrected capacitance C0a with the reference signal Cth. That is, if the difference from the reference signal Cth is within ΔCth, the sensor electrode 11 is determined to be normal, and if it exceeds ΔCht, the sensor electrode 11 is determined to be abnormal. In this way, in the comparison between the first capacitance Cx1 and the reference signal Cth and the comparison between the second capacitance Cx2 and the reference signal Cth, the sensor electrode 11 is diagnosed in consideration of the correction value due to the environment dependence. Is going. Therefore, the diagnosis of the sensor electrode 11 can be performed with high accuracy regardless of the environment.

Here, the first diagnosis in the diagnostic circuit 53 is performed, for example, as shown in FIG. First, the first diagnosis is an internal diagnosis of the first system detection circuit 21 (S11). Subsequently, the first capacitance Cx1 is corrected in consideration of the correction value due to the environment dependence (S12). Subsequently, the sensor electrode 11 is diagnosed by comparing the correction value of the first capacitance Cx1 with the reference signal Cth (S13). The second diagnosis in the diagnostic circuit 53 is performed, for example, as shown in FIG. First, in the second diagnosis, an internal diagnosis of the second system detection circuit 23 is performed (S14). Subsequently, the second capacitance Cx2 is corrected in consideration of the correction value due to the environment dependence (S15). Subsequently, the sensor electrode 11 is diagnosed by comparing the correction value of the second capacitance Cx2 with the reference signal Cth (S16). The order of the internal diagnosis and the comparative diagnosis can be reversed.

(6-2. Reference device 51 of the second example)
In the detection device 5 of the fourth example and its modification, the reference device 51 can output a reference signal of the sensor electrode 11 in a reference state that is not affected by the proximity of the detection target 3.

The second reference device 51 will be described with reference to FIGS. 18 to 24. The reference device 51 is a reference electrode that is arranged in the same environment as the sensor electrode 11 and has the same capacitance dependence as the sensor electrode 11. Therefore, as shown in FIG. 18, the reference signal Cth output by the reference device 51 has environment dependence. The reference signal Cth, the capacitance C0 detected when the detection target 3 is not close to each other, and the capacitance C1 detected when the detection target 3 is close to each other have a correlation. For example, they make the same changes to changes in the environment.

As shown in FIGS. 19 and 20, in the environments S1 and S2, the detected capacitance becomes C0 before the proximity of the detection target 3 and becomes C1 after the proximity, and the reference signal is Cth. Become. However, C0, C1, Cth in the environment S1 and C0, C1, Cth in the environment S2 have different values. However, the difference ΔC0 between C0 and C1 and the difference ΔC1 between C1 and Cth are the same. Therefore, the reference signal Cth and the capacitances C0 and C1 also change in response to changes in the environment.

That is, the first system detection circuit 21 can detect the proximity of the detection target 3 based on the comparison result between the first capacitance Cx1 and the reference signal Cth without making any correction. Further, the second system detection circuit 23 can detect the proximity of the detection target 3 based on the comparison result between the second capacitance Cx2 and the reference signal Cth without correction. Therefore, it is possible to detect the proximity of the detection target 3 with high accuracy without correction.

Here, the reference electrode, which is the reference device 51, has a smaller area than the sensor electrode 11. The larger the area of the sensor electrode 11, the better the detection accuracy. On the other hand, the reference device 51 does not require detection accuracy. Therefore, the reference electrode of the reference device 51 can be made smaller than the sensor electrode 11. Therefore, the degree of freedom in arranging the reference device 51 is increased.

Further, as shown in FIGS. 21 and 22, the diagnostic circuit 53 diagnoses the sensor electrode 11 by comparing the detected capacitance C0 with the reference signal Cth. That is, if the difference from the reference signal Cth is within ΔCth, the sensor electrode 11 is determined to be normal, and if it exceeds ΔCht, the sensor electrode 11 is determined to be abnormal. In this way, in the comparison between the first capacitance Cx1 and the reference signal Cth and the comparison between the second capacitance Cx2 and the reference signal Cth, even if the environment changes, the sensor electrode is not corrected. Eleven diagnoses can be made. By making the reference device 51 environmentally dependent in this way, the sensor electrode 11 can be diagnosed with high accuracy regardless of the environment.

Here, the first diagnosis in the diagnostic circuit 53 is performed, for example, as shown in FIG. 23. First, in the first diagnosis, an internal diagnosis of the first system detection circuit 21 is performed (S21). Subsequently, the sensor electrode 11 is diagnosed by comparing the first capacitance Cx1 and the reference signal Cth without correction (S22). The second diagnosis in the diagnostic circuit 53 is performed, for example, as shown in FIG. 24. First, in the second diagnosis, an internal diagnosis of the second system detection circuit 23 is performed (S23). Subsequently, the sensor electrode 11 is diagnosed by comparing the second capacitance Cx2 with the reference signal Cth without correction (S24). The order of the internal diagnosis and the comparative diagnosis can be reversed.

1,1a, 4,5: Capacitance type proximity detector, 2: Human collaborative robot, 3: Detection target, 10: Sensor body, 11: Sensor electrode, 12: Ground electrode, 20, 30, 50: Circuit Unit, 21: 1st system detection circuit, 22: 1st system processing device, 23: 2nd system detection circuit, 24: 2nd system processing device, 25, 32, 52: Switch, 25a, 32a, 52a: 1st Switch, 25b, 32b, 52b: Second switch, 26, 33, 53: Diagnostic circuit, 31: Communication device, 40: External device, 51: Reference device, Cx: Capacitance

Claims (16)

One sensor electrode for detecting the proximity of the detection target,
A switch that switches one of the multiple systems to connect to the sensor electrode,
The first system of the plurality of systems is configured, the first signal detected by the sensor electrode is acquired in a state of being connected to the sensor electrode by the switch, and the sensor electrode and the sensor electrode are obtained based on the first signal. A first system detection circuit that detects the first capacitance between the detection target and
A first system processing device that performs processing on the target device based on the first capacitance detected by the first system detection circuit, and
The second system of the plurality of systems is configured, and the second signal detected by the sensor electrode is acquired at a timing different from the first signal in a state of being connected to the sensor electrode by the switch, and the second signal is acquired. A second system detection circuit that detects the second capacitance between the sensor electrode and the detection target based on the second signal, and
A second system processing device that performs processing on the target device based on the second capacitance detected by the second system detection circuit, and
The first capacitance and the second capacitance detected by the first system detection circuit at the timing when the first capacitance and the second capacitance become the same value when the sensor electrode is normal. The sensor electrode is diagnosed based on the difference from the second capacitance detected by the detection circuit, or the comparison result between each of the first capacitance and the second capacitance and the reference capacitance. Diagnostic circuit and
Capacitive proximity detection device with safety function. The switch is a capacitance type proximity detection device having a safety function according to claim 1 , wherein each system of the plurality of systems is sequentially switched so as to be sequentially connected to the sensor electrode. The diagnostic circuit is
While the sensor electrode and the first system detection circuit are connected by the switch, the sensor electrode is diagnosed using the second capacitance detected by the second system detection circuit.
A claim that the sensor electrode is diagnosed using the first capacitance detected by the first system detection circuit while the sensor electrode and the second system detection circuit are connected by the switch. Capacitance type proximity detection device having the safety function according to 2. The switch is
A state in which the sensor electrode is connected to the first system detection circuit, and the second system detection circuit is connected to another device.
A state in which the sensor electrode and the second system detection circuit are connected, and the first system detection circuit and the other device are connected.
The capacitance type proximity detection device having the safety function according to claim 2. The diagnostic circuit is
While the sensor electrode and the first system detection circuit are connected by the switch, information is acquired from the other device, and the sensor electrode is diagnosed using the information acquired from the other device. Do,
While the sensor electrode and the second system detection circuit are connected by the switch, information is acquired from the other device, and the sensor electrode is diagnosed using the information acquired from the other device. The capacitive proximity detection device having the safety function according to claim 4. The separate device is a capacitance type proximity detection device having a safety function according to claim 4 or 5, which is a communication device that communicates with an external device. The static electricity according to claim 4 or 5, wherein the separate device is a reference device capable of outputting a reference signal of the sensor electrode as the reference capacitance in a reference state that is not affected by the proximity of the detection target. Capacitive proximity detection device. The one according to any one of claims 1-7, wherein the diagnostic circuit determines that the sensor electrode is abnormal when the difference between the first capacitance and the second capacitance is larger than a predetermined value. Capacitive proximity detector with safety function. The capacitance type proximity detection device further includes
A reference device capable of outputting a reference signal of the sensor electrode as the reference capacitance in a reference state that is not affected by the proximity of the detection target is provided.
The diagnostic circuit claims that the sensor electrode is diagnosed by comparing the first capacitance with the reference signal and comparing the second capacitance with the reference signal. Capacitance type proximity detection device having the safety function according to any one of 1-7. The capacitance type proximity detection device having a safety function according to claim 9, wherein the reference device is a capacitor having a fixed capacitance. The capacitance between the sensor electrode and the detection target is environment-dependent and is environmentally dependent.
The diagnostic circuit of the sensor electrode takes into consideration the correction value due to the environment dependence in the comparison between the first capacitance and the reference signal and the comparison between the second capacitance and the reference signal. The capacitance type proximity detection device having the safety function according to claim 10, which makes a diagnosis. The first system detection circuit detects the proximity of the detection target in consideration of the correction value due to the environment dependence in the comparison between the first capacitance and the reference signal.
The safety according to claim 11, wherein the second system detection circuit detects the proximity of the detection target in consideration of the correction value due to the environment dependence in the comparison between the second capacitance and the reference signal. Capacitive proximity detection device with functions. The capacitance type proximity having a safety function according to claim 9, wherein the reference device is a reference electrode arranged in the same environment as the sensor electrode and having the same capacitance dependence as the sensor electrode. Detection device. The capacitance type proximity detection device having a safety function according to claim 13, wherein the reference electrode, which is the reference device, has a smaller area than the sensor electrode. The first system detection circuit detects the proximity of the detection target based on the comparison result between the first capacitance and the reference signal.
The capacitance having the safety function according to claim 13 or 14, wherein the second system detection circuit detects the proximity of the detection target based on the comparison result between the second capacitance and the reference signal. Type proximity detector. The sensor electrodes are arranged in a human collaborative robot and
The safety according to any one of claims 1-15, wherein the first system detection circuit and the second system detection circuit detect a capacitance between the sensor electrode and a person as a detection target. Capacitive proximity detection device with functions.

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