Electric actuator, control device, and control program

Abstract

To achieve high controllability of connection control of an output member driven through an intermediate member according to an output state of a driving source and the intermediate member.SOLUTION: An electric actuator includes a driving source for generating power; an output member driven through an intermediate member according to an output state of the driving source; a connection part capable of being reversibly connecting and disconnecting the intermediate member and the output member; and a control section for commanding disconnecting of the disconnection of the intermediate member and the output member on the basis of detection values before and after conversion of a signal or motion converted by a transmission system from the driving source to the output member.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electric actuator, a control device, and a control program.

Background Art

[0002] As one of the failure events of an electric actuator, there is a fixation of the output shaft due to a failure of the mechanical part. When the output shaft of an electric actuator used in an active vibration control device becomes fixed, the electric actuator becomes equivalent to a fixed rod, so it becomes a new path for transmitting the vibration of the vibration source, and the vibration becomes larger than the state without the active vibration control device.

[0003] Further, in a mechanism that duplicates power to continue the operation of the electric actuator, when one electric actuator becomes fixed, the operation of the other electric actuator may be inhibited, and the fail-safe mechanism may not work properly. Therefore, when the actuator becomes fixed, it is desirable to release the connection of the mechanical part to eliminate the fixed state.

[0004] Patent Document 1 discloses a technique for releasing the fixed state during an abnormality by providing a retraction mechanism at a portion where the output shaft of the electric actuator is attached.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the technique disclosed in Patent Document 1, the defect detection unit compares the position of the rod required for the electric actuator main body by a control signal from the aircraft side with the actual position of the rod, and determines that a defect such as mechanical jamming has occurred in the electric actuator main body when a deviation of a predetermined value or more is detected. Therefore, in the technique disclosed in Patent Document 1, in order to detect the position deviation of the rod, it is necessary to give the position of the rod required for the electric actuator main body by a control signal from the aircraft side, and abnormality detection and connection release cannot be performed by the electric actuator alone. Therefore, an object of the present invention is to provide an electric actuator, a control device, and a control program capable of improving the controllability of connection control between an output member driven via an intermediate member according to the output state of a drive source and the intermediate member.

Means for Solving the Problems

[0007] According to an electric actuator according to an aspect of the present invention, in order to solve the above problems, there is provided a drive source that generates power, an output member that is driven via an intermediate member according to the output state of the drive source, a connection portion that can reversibly perform connection and disconnection between the intermediate member and the output member, and a control unit that commands disconnection between the intermediate member and the output member based on a detection value before conversion and a detection value after conversion of a signal or motion converted in a transmission system from the drive source to the output member.

[0008] Thereby, based on the detection value before conversion and the detection value after conversion of the signal or motion converted in the transmission system, the connection between the intermediate member and the output member can be released without destroying the connection portion. Therefore, it is possible to release the fixed state of the transmission system while suppressing an increase in the load of the control system of the electric actuator, and to reconnect the intermediate member and the output member according to the state of the transmission system, thereby improving the safety, efficiency, and comfort during use of the electric actuator.

[0009] Further, according to the electric actuator according to one aspect of the present invention, it includes a first sensor for detecting the output state of the drive source and a second sensor for detecting the state of the output member. When the first sensor detects that the drive source is normal and the control unit detects that the detection value of the second sensor does not change for a predetermined time, the control unit issues a connection release signal, and the connection unit releases the connection between the intermediate member and the output member based on the connection release signal from the control unit.

[0010] Thus, by performing a simple calculation based on the detection results of the first sensor and the second sensor, it is possible to eliminate the stuck state of the power transmission system up to the output member beyond the drive source without destroying the connection part. Therefore, it is possible to improve the safety, efficiency, and comfort during the use of the electric actuator while suppressing an increase in the load of the control system of the electric actuator.

[0011] Further, according to the electric actuator according to one aspect of the present invention, the control unit further includes an estimation unit that calculates an estimated value, which is the estimated state of the output member, based on the detection value of the first sensor. When it is detected that the estimated value is equal to or greater than a predetermined value and the detection value of the second sensor does not change for a predetermined time, the control unit issues the connection release signal.

[0012] Thus, while driving the output member via the intermediate member from the drive source, by performing a simple calculation based on the state of the output member expected from the output state of the drive source and the detection result of the state of the output member, it is possible to eliminate the stuck state of the power transmission system up to the output member beyond the drive source without destroying the connection part. Therefore, it is possible to improve the safety, efficiency, and comfort during the use of the electric actuator while suppressing an increase in the load of the control system of the electric actuator.

[0013] Further, according to the electric actuator according to one aspect of the present invention, when an abnormality in the transmission system is detected, the control unit releases the connection between the intermediate member and the output member, and when the transmission system is normal, the control unit connects the intermediate member and the output member.

[0014] Accordingly, without destroying the components of the electric actuator, it is possible to disable the operation of the electric actuator according to the state of the electric actuator, or to enable the operation of the electric actuator according to the state of the electric actuator without replacing the components of the electric actuator, thereby improving the safety, efficiency, comfort, etc. during the use of the electric actuator.

[0015] Further, according to the electric actuator according to one aspect of the present invention, the control unit commands the disconnection of the connection between the intermediate member and the output member based on at least any two detection values of the detection value of the state of the drive source, the detection value of the state of the intermediate member, and the detection value of the state of the output member.

[0016] Accordingly, based on the abnormality of not only the drive source but also the intermediate member and the output member downstream of the drive source, the connection between the intermediate member and the output member can be disconnected, and while achieving higher accuracy and efficiency in the abnormality analysis of the electric actuator, it is possible to improve the safety, efficiency, comfort, etc. during the use of the electric actuator.

[0017] Further, according to the electric actuator according to one aspect of the present invention, the drive source includes a motor, the intermediate member includes a linear motion device that converts the rotational motion input from the motor into a linear motion, the output member includes an output shaft that outputs an axial force based on the linear motion converted by the linear motion device, and the control unit commands the disconnection of the connection between the linear motion device and the output shaft based on the signal converted in the transmission system from the motor to the output shaft or the detection value before conversion and the detection value after conversion of the motion.

[0018] As a result, it becomes possible to obtain a large axial shaft force from a relatively small input torque, suppress the increase in size of the electric actuator, and use it as a vibration damping device for a vehicle or the like. At the same time, it is possible to detect an abnormality based on the detected value before conversion and the detected value after conversion of the internal state of the electric actuator alone, improve the diversity and flexibility regarding data processing or data acquisition necessary for detecting an abnormality in the transmission system and disconnecting the connection, and control the connection of the connection part. For this reason, while relaxing the restrictions on the locations or states where an abnormality in the transmission system can be detected, it is possible to perform abnormality detection and connection disconnection with the electric actuator alone, achieve higher accuracy and efficiency in the abnormality analysis of the electric actuator, and improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0019] Further, according to the electric actuator according to one aspect of the present invention, the control unit commands the disconnection of the connection between the linear motion device and the output shaft based on the estimated value of the axial force estimated from the detected value of the drive current of the motor and the detected value of the position of the output shaft.

[0020] As a result, while enabling control of the position of the output shaft based on the drive current of the motor, by detecting the drive current of the motor and the position of the output shaft, the connection between the linear motion device and the output shaft can be disconnected. For this reason, while achieving higher accuracy and efficiency in the abnormality analysis of the electric actuator, it becomes possible to eliminate the fixed state of the power transmission system up to the output member beyond the drive source, and improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0021] Further, according to the electric actuator according to one aspect of the present invention, the control unit commands the disconnection of the connection between the linear motion device and the output shaft when the estimated value of the axial force is equal to or greater than a certain value and the detected value of the position of the output shaft does not change for a certain period of time.

[0022] By performing simple calculations based on the detected drive current of the motor and the detected position of the output shaft, the connection between the linear actuator and the output shaft can be released. Therefore, it is possible to eliminate the stuck state of the power transmission system up to the output shaft beyond the motor while suppressing an increase in the load of the control system of the electric actuator, and it is also possible to improve the accuracy and efficiency of the connection control of the connecting portion, thereby improving the safety, efficiency, and comfort when using the electric actuator.

[0023] Also, according to the electric actuator according to one aspect of the present invention, the control unit commands the release of the connection between the linear actuator and the output shaft based on the detected value of the drive current of the motor and the detected value of the position of the output shaft.

[0024] Thereby, while enabling control of the position of the output shaft based on the drive current of the motor, by detecting the drive current of the motor and the position of the output shaft, the connection between the linear actuator and the output shaft can be released. Therefore, it is possible to eliminate the stuck state of the power transmission system up to the output member beyond the drive source while improving the accuracy and efficiency of the abnormality analysis of the electric actuator, and it is also possible to improve the safety, efficiency, and comfort when using the electric actuator.

[0025] Also, according to the electric actuator according to one aspect of the present invention, when the detected value of the drive current of the motor is equal to or greater than a certain value and the amount of change in the detected value of the position of the output shaft within a certain time is equal to or less than a certain value, the control unit commands the release of the connection between the linear actuator and the output shaft.

[0026] Accordingly, by performing a simple calculation based on the detection results of the drive current of the motor and the position of the output shaft, the connection between the linear actuator and the output shaft can be released. For this reason, while suppressing an increase in the load of the control system of the electric actuator, it becomes possible to eliminate the stuck state of the power transmission system up to the output shaft beyond the motor, and it becomes possible to improve the accuracy and efficiency of the connection control of the connecting portion, and it becomes possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0027] Also, according to the electric actuator according to one aspect of the present invention, the control unit commands the release of the connection between the linear actuator and the output shaft based on the detected value of the drive current of the motor and the detected value of the rotational position of the motor.

[0028] Accordingly, while enabling control of the rotational position of the motor based on the drive current of the motor, by detecting the drive current and the rotational position of the motor, the connection between the linear actuator and the output shaft can be released. For this reason, while improving the accuracy and efficiency of the abnormality analysis of the electric actuator, it becomes possible to eliminate the stuck state of the power transmission system up to the output member beyond the drive source, and it becomes possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0029] Also, according to the electric actuator according to one aspect of the present invention, when the detected value of the drive current of the motor is equal to or greater than a certain value and the amount of change of the detected value of the rotational position of the motor within a certain time is equal to or less than a certain value, the control unit commands the release of the connection between the linear actuator and the output shaft.

[0030] Accordingly, by performing a simple calculation based on the detection results of the drive current and the rotational position of the motor, the connection between the linear actuator and the output shaft can be released. For this reason, while suppressing an increase in the load of the control system of the electric actuator, it becomes possible to eliminate the stuck state of the power transmission system up to the output shaft beyond the motor, and it becomes possible to achieve higher precision and efficiency in the connection control of the connecting portion, and it becomes possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0031] Also, according to the electric actuator according to one aspect of the present invention, the control unit issues an instruction to release the connection between the linear actuator and the output shaft based on the detected value of the drive current of the motor and the detected value of the axial force of the output shaft.

[0032] Accordingly, while enabling control of the axial force based on the drive current of the motor, by detecting the drive current of the motor and the axial force of the output shaft, the connection between the linear actuator and the output shaft can be released. For this reason, while achieving higher precision and efficiency in the abnormal analysis of the electric actuator, it becomes possible to eliminate the stuck state of the power transmission system up to the output member beyond the drive source, and it becomes possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0033] Also, according to the electric actuator according to one aspect of the present invention, when the detected value of the drive current of the motor is equal to or greater than a certain value and the detected value of the axial force of the output shaft is equal to or less than a certain value, the control unit issues an instruction to release the connection between the linear actuator and the output shaft.

[0034] Accordingly, by performing a simple calculation based on the detection results of the drive current of the motor and the axial force of the output shaft, the connection between the linear actuator and the output shaft can be released. For this reason, while suppressing an increase in the load of the control system of the electric actuator, it becomes possible to eliminate the stuck state of the power transmission system up to the output shaft beyond the motor, and it becomes possible to achieve higher precision and efficiency in the connection control of the connecting portion, and it becomes possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0035] Also, according to the electric actuator according to one aspect of the present invention, the control unit commands the disconnection between the linear motion device and the output shaft based on the estimated value of the linear motion position of the linear motion device estimated from the detected value of the rotational position of the motor and the detected value of the position of the output shaft.

[0036] Thereby, while enabling control of the linear motion of the linear motion device based on the rotational motion of the motor, by detecting the rotational position of the motor and the position of the output shaft, the connection between the linear motion device and the output shaft can be released. For this reason, while improving the accuracy and efficiency of the abnormality analysis of the electric actuator, it is possible to eliminate the fixed state of the power transmission system up to the output member beyond the drive source, and it is possible to improve the safety, efficiency, and comfort when using the electric actuator.

[0037] Also, according to the electric actuator according to one aspect of the present invention, when the difference between the estimated value of the linear motion position of the linear motion device and the detected value of the position of the output shaft is equal to or less than a certain value and the change amount within a certain time is equal to or less than a certain value, the control unit commands the disconnection between the linear motion device and the output shaft.

[0038] Thereby, by performing a simple calculation based on the detection results of the rotational position of the motor and the position of the output shaft, the connection between the linear motion device and the output shaft can be released. For this reason, while suppressing an increase in the load of the control system of the electric actuator, it is possible to eliminate the fixed state of the power transmission system up to the output shaft beyond the motor, and it is possible to improve the accuracy and efficiency of the connection control of the connection part, and it is possible to improve the safety, efficiency, and comfort when using the electric actuator.

[0039] Also, the electric actuator according to one aspect of the present invention is applied to a vibration damping device.

[0040] By outputting an axial force that is out of phase with the vibration from the vibration source from the output shaft, it becomes possible to cancel out the vibration from the vibration source. Also, even when the movement of the linear motion device is restricted according to the fixed state or load state of the power transmission system, it is possible to prevent the movement of the output shaft from being restricted via the linear motion device, and it becomes possible to improve the safety, efficiency, comfort, etc. when an electric actuator is used as a vibration damping device.

[0041] Further, according to the electric actuator according to one aspect of the present invention, it further includes a motor control unit that controls the motor based on the detected value of the drive current of the motor and the detected value of the rotational position of the motor.

[0042] Thereby, while making it possible to control the motor based on the drive current and rotational position of the motor, it becomes possible to detect an abnormal state of the motor. At this time, sensors for detecting the drive current and rotational position of the motor can be used not only for motor control but also for motor abnormality detection, eliminating the need to separately provide sensors dedicated to motor abnormality detection. Thus, it becomes possible to suppress the increase in size and cost of the electric actuator while achieving high-precision and efficient connection control of the connection part.

[0043] Further, according to the control device according to one aspect of the present invention, it includes a motor control unit that controls a motor that drives a linear motion device connected to the output shaft, a state detection unit that detects the state of the transmission system based on the signal or motion converted in the transmission system from the motor to the output shaft and the detected values before and after conversion, and a connection control unit that controls the connection between the linear motion device and the output shaft based on the detection result of the state of the transmission system.

[0044] Thereby, it becomes possible to detect an abnormality based on the detected values before and after conversion of the internal state of the electric actuator alone, achieve high-precision and efficient abnormality analysis of the electric actuator, and perform abnormality detection and connection control with the electric actuator alone.

[0045] According to a control program according to an aspect of the present invention, a computer is caused to execute: a step of acquiring a detection value before conversion of a signal or motion converted in a transmission system from a motor that drives a linear motion device connected to an output shaft to the output shaft; a step of acquiring a detection value after conversion of the signal or motion converted in the transmission system; and a step of controlling the connection between the linear motion device and the output shaft based on the detection value before conversion and the detection value after conversion of the signal or motion converted in the transmission system.

[0046] As a result, it is possible to detect an abnormality based on the detection value before conversion and the detection value after conversion of the internal state of the electric actuator alone, and while improving the accuracy and efficiency of the abnormality analysis of the electric actuator, it is possible to perform abnormality detection and connection control with the electric actuator alone.

Advantages of the Invention

[0047] According to one aspect of the present invention, it is possible to improve the controllability of the connection control between the output member driven via the intermediate member and the intermediate member according to the output state of the drive source.

Brief Description of the Drawings

[0048]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the present invention, and not all combinations of the features described in the embodiments are essential to the configuration of the present invention. The configuration of the embodiments can be appropriately modified or changed according to the specifications of the device to which the present invention is applied and various conditions (usage conditions, usage environments, etc.). The technical scope of the present invention is determined by the scope of the claims and is not limited by the following individual embodiments. In addition, the drawings used in the following description may differ from the actual structure, scale, shape, etc. in order to make each configuration easier to understand.

[0050] FIG. 1 is a block diagram showing the configuration of an electric actuator according to an embodiment. In FIG. 1, the electric actuator includes a control device 1 and a power unit 9.

[0051] The power unit 9 generates, converts, and transmits power based on a cooperative operation. For example, the power unit 9 can generate, convert, and transmit power based on the cooperative operation between a drive source that generates power and an output member that is driven via an intermediate member according to the output state of the drive source. The intermediate member can convert the output of the drive source or transmit it to the output member. In the example of FIG. 1, the drive source is a motor 2, the intermediate members are reduction gears 3A to 3C and a linear motion device 5, and the output member is an output shaft 6. At this time, the power unit 9 can constitute a transmission system that transmits a signal or motion while converting the signal or motion. The signal referred to here is, for example, an electrical signal. The motion referred to here is, for example, a rotational motion, a linear motion, a reciprocating motion, or a rocking motion.

[0052] The control device 1 controls the power unit 9 and monitors the operation of the power unit 9. At this time, the control device 1 can issue an instruction to disconnect the connection between the intermediate member and the output member based on the signal or motion converted in the transmission system from the drive source to the output member, and the detected value before conversion and the detected value after conversion.

[0053] For example, when the drive source is in a normal state, the control device 1 can issue a disconnection signal Sr for instructing the disconnection of the connection between the intermediate member and the output member based on the detected value of the state of the output member. Also, the control device 1 calculates an estimated value, which is the estimated state of the output member, based on the detected value of the output state of the drive source, and issues a disconnection signal Sr for instructing the disconnection of the connection between the intermediate member and the output member based on the estimated value and the detected value of the state of the output member.

[0054] Alternatively, the control device 1 may issue a disconnection signal Sr for instructing the disconnection of the connection between the intermediate member and the output member based on the detected value of the state of the intermediate member when the drive source is in a normal state. Also, the control device 1 calculates an estimated value, which is the estimated state of the intermediate member, based on the detected value of the output state of the drive source, and issues a disconnection signal Sr for instructing the disconnection of the connection between the intermediate member and the output member based on the estimated value and the detected value of the state of the intermediate member.

[0055] Alternatively, the control device 1 may issue a disconnection signal Sr for instructing the disconnection of the connection between the intermediate member and the output member based on the detected value of the state of the output member when the intermediate member is in a normal state. Also, the control device 1 calculates an estimated value, which is the estimated state of the output member, based on the detected value of the output state of the intermediate member, and issues a disconnection signal Sr for instructing the disconnection of the connection between the intermediate member and the output member based on the estimated value and the detected value of the state of the output member.

[0056] The control device 1 includes a motor control unit 11, a motor angle calculation unit 12, a current sensor 13, an abnormality detection unit 14, and a connection control unit 15. The abnormality detection unit 14 includes an estimation unit 14A that calculates an estimated value, which is the estimated state of the output member, based on the detected value of the output state of the drive source. This estimation unit 14A may be realized by an arithmetic device such as a processor.

[0057] The power unit 9 includes a motor 2, speed reducers 3A to 3C, bearings 4, a linear motion device 5, a connection part 5C, an output shaft 6, and a sensor 7. The motor 2 includes a rotational position sensor 2A. The rotational position sensor 2A can be used as a first sensor that detects the output state of the drive source. The linear motion device 5 includes a screw shaft 5A and a nut 5B. The motor 2 is connected to the linear motion device 5 via the speed reducers 3A to 3C. The output shaft 6 is connected to the linear motion device 5 via the connection part 5C.

[0058] The motor control unit 11 controls the motor 2 based on the detected value of the drive current of the motor 2 and the detected value of the rotational position of the motor 2. The motor control unit 11 can include an inverter that generates the drive current of the motor 2. Further, the motor control unit 11 can control the motor 2 based on the detection result of the abnormal state of the power unit 9. The motor angle calculation unit 12 calculates the motor angle based on the detected value of the rotational position of the motor 2. The current sensor 13 detects the drive current that drives the motor 2.

[0059] The abnormality detection unit 14 detects an abnormal state of the power unit 9 based on the signal converted by the power unit 9 or the detection values before and after the conversion of the motion. At this time, the combination of the detection value before conversion and the detection value after conversion can be selected, for example, from motor input and motor output, motor input and input of the linear motion device 5, motor input and output of the linear motion device 5, motor input and output of the output shaft 6, motor output and input of the linear motion device 5, motor output and output of the linear motion device 5, motor output and output of the output shaft 6, input and output of the linear motion device 5, input of the linear motion device 5 and output of the output shaft 6, or output of the linear motion device 5 and output of the output shaft 6. For example, the abnormality detection unit 14 can detect an abnormal state of the power unit 9 based on the detection value of the state of the motor 2 and the detection value of the state of the output shaft 6. Note that the abnormal state of the power unit 9 is, for example, a stuck state or a high-load state of the power transmission system such as the motor 2, the gears of the speed reducers 3A to 3C, or the linear motion parts of the linear motion device 5, or a chip or detachment of the gears of the speed reducers 3A to 3C.

[0060] At this time, in order to detect the state of the power unit 9 based on the signal converted by the power unit 9 or the detection values before and after the conversion of the motion, the estimation unit 14A can calculate an estimated value estimated as the state after the conversion of the signal or motion converted by the power unit 9A based on the detection value before the conversion of the signal or motion converted by the power unit 9A. For example, the estimation unit 14A can calculate an estimated value estimated as the state of the output shaft 6 based on the detection value of the state of the motor 2. Then, the abnormality detection unit 14 can detect an abnormal state of the power unit 9A based on the comparison result between the detection value of the state of the output shaft 6 and the estimated value estimated as the state of the output shaft 6 from the detection value of the state of the motor 2.

[0061] The connection control unit 15 controls the connection of the connection part 5C based on the detection result of the state of the transmission system from the motor 2 to the output shaft 6. For example, when an abnormality in the transmission system from the motor 2 to the output shaft 6 is detected, the connection control unit 15 can release the connection between the linear motion device 5 and the output shaft 6, and when the transmission system from the motor 2 to the output shaft 6 is normal, the connection control unit 15 can connect the linear motion device 5 and the output shaft 6.

[0062] The motor 2 performs a rotational motion based on the drive current input from the motor control unit 11. At this time, the motor 2 can be used as a drive source for the linear motion device 5. The rotation position sensor 2A detects the rotation position of the motor 2. The speed reducers 3A to 3C generate the input of the linear motion device 5 based on the output of the motor 2. The speed reducers 3A to 3C can be provided with gears that convert the rotation speed of the motor 2 and input it to the linear motion device 5. The bearing 4 supports the screw shaft 5A so that the screw shaft 5A can rotate based on the input from the speed reducers 3A to 3C.

[0063] The linear motion device 5 converts the rotational motion of the screw shaft 5A into a linear motion of the nut 5B. At this time, a rotational motion is input from the speed reducers 3A to 3C to the linear motion device 5, and an axial force is output from the linear motion device 5 to the output shaft 6. The linear motion device 5 is, for example, a ball screw in which the screw shaft 5A and the nut 5B are screwed together.

[0064] The output shaft 6 outputs an axial force based on the linear motion converted by the nut 5B. The shape of the output shaft 6 is, for example, a cylindrical shape into which the screw shaft 5A can be inserted. The connecting portion 5C can reversibly connect and disconnect the linear motion device 5 and the output shaft 6. At this time, the connecting portion 5C connects or disconnects the linear motion device 5 and the output shaft 6 based on the control from the connection control unit 15. The connection between the connecting portion 5C and the connection control unit 15 may be wired or wireless. The connecting portion 5C may be a cotter that can be inserted into and removed from the nut 5B through the side surface of the output shaft 6, or an electromagnetic clutch or an electromagnetic brake, or a clamping mechanism by pneumatic, hydraulic or actuator. The connecting portion 5C may be installed inside the output shaft 6.

[0065] The sensor 7 detects the state of the output shaft 6. The sensor 7 can be used as a second sensor that detects the state of the output member driven via the intermediate member according to the output state of the drive source. The state of the output shaft 6 may be the axial force output from the output shaft 6, the position of the output shaft 6, the speed of the output shaft 6, or the acceleration of the output shaft 6. At this time, as the sensor 7, an axial force sensor, a position sensor, a speed sensor, or an acceleration sensor can be used. Note that the rotational position sensor 2A and the current sensor 13 can be used to detect the state of the motor 2.

[0066] The detection value of the rotational position of the motor 2 detected by the rotational position sensor 2A is input to the motor angle calculation unit 12. Then, in the motor angle calculation unit 12, based on the detection value of the rotational position of the motor 2, the motor angle is calculated and input to the motor control unit 11 and the abnormality detection unit 14. The drive current for driving the motor 2 is detected by the current sensor 13, and the detection value of the drive current is input to the motor control unit 11 and the abnormality detection unit 14.

[0067] Then, in the motor control unit 11, based on the detection value of the drive current of the motor 2 and the detection value of the rotational position, the drive current of the motor 2 is controlled and the rotational movement of the motor 2 is controlled. The rotational movement of the motor 2 is decelerated by the speed reducers 3A to 3C and then input to the linear motion device 5. Then, in the linear motion device 5, the rotational movement input to the linear motion device 5 is converted into a linear motion and output to the output shaft 6 via the connecting portion 5C.

[0068] This electric actuator can be used, for example, in a vibration damping device of a vehicle or the like. For example, in the case of a vibration damping device of a railway vehicle, an electric actuator can be installed between the vehicle body and the bogie. Then, by outputting an axial force having a phase opposite to the vibration of the vehicle body from the output shaft 6, the vibration of the vehicle body can be reduced.

[0069] At this time, in the sensor 7, the state of the output shaft 6 is detected, and the detected value of the state of the output shaft 6 is input to the abnormality detection unit 14. Then, in the abnormality detection unit 14, an abnormal state of the power unit 9 is detected based on the detected value of the state of the motor 2 and the detected value of the state of the output shaft 6. When the abnormality detection unit 14 detects an abnormal state of the power unit 9, the detection result is output to the connection control unit 15. When notified of the abnormal state of the power unit 9, the connection control unit 15 releases the connection between the linear motion device 5 and the output shaft 6 via the connection part 5C. Then, when the abnormal state of the power unit 9 is released, the connection control unit 15 connects the linear motion device 5 and the output shaft 6 via the connection part 5C.

[0070] For example, when the rotation position sensor 2A detects that the motor 2 is normal and the control device 1 detects that the detected value of the sensor 7 does not change for a predetermined time, the control device 1 can issue a connection release signal Sr to the connection part 5C. Then, the connection part 5C can release the connection between the linear motion device 5 and the output shaft 6 based on the connection release signal Sr from the control device 1. Further, the estimation unit 14A can calculate an estimated value that is the estimated state of the output shaft 6 based on the detected value of the rotation position sensor 2A. Then, when the control device 1 detects that the estimated value that is the estimated state of the output shaft 6 is equal to or greater than a predetermined value and the detected value of the sensor 7 does not change for a predetermined time, the control device 1 can issue a connection release signal Sr to the connection part 5C.

[0071] Here, the electric actuator can detect an abnormal state of the power unit 9 based on the signal converted by the power unit 9 or the detected value before and after the conversion of the motion, thereby relaxing the restrictions on the locations or states where the abnormality of the power unit 9A can be detected, and performing abnormality detection and connection release with the electric actuator alone. For this reason, it is possible to improve the diversity and flexibility regarding data processing or data acquisition necessary for abnormality detection and connection release of the power unit 9A, to achieve higher accuracy and efficiency in the abnormality analysis of the electric actuator, and to improve the safety, efficiency, and comfort when using the electric actuator.

[0072] For example, assume that an electric actuator is installed between the car body and the bogie of a railway vehicle. At this time, if the power transmission system becomes fixed, the electric actuator will always be in a stretched state, and the vibration of the bogie will be directly transmitted to the car body via the electric actuator, resulting in a deterioration of the riding comfort of the railway vehicle. At this time, the connection control unit 15 releases the connection between the linear motion device 5 and the output shaft 6 via the connection part 5C so that the output shaft 6 is not restricted by the linear motion of the linear motion device 5. Thereby, even when the power transmission system becomes fixed, it is possible to prevent the vibration of the bogie from being directly transmitted to the car body via the electric actuator, and it is possible to improve the riding comfort of the railway vehicle.

[0073] In addition, by providing the linear motion device 5 in the electric actuator, it becomes possible to obtain a large axial output from a relatively small input torque, suppress the increase in size of the electric actuator, and use it as a vibration damping device for the vehicle, etc. At the same time, it becomes possible to detect abnormalities in the linear motion device 5 and the output shaft 6 beyond the motor 2. Therefore, even when high safety is required, it is possible to apply the electric actuator without increasing the difficulty of handling and installation of the electric actuator.

[0074] In addition, by using the detection value of the current sensor 13 or the detection value of the rotation position sensor 2A not only for motor control but also for abnormality detection, it becomes possible to detect the abnormal state of the power unit 9 without separately providing a sensor dedicated to abnormality detection. Therefore, it is possible to suppress the increase in size and cost of the electric actuator and achieve higher accuracy and efficiency in abnormality analysis.

[0075] In addition, by providing the abnormality detection unit 14 and the connection control unit 15 in the control device 1 and installing the connection part 5C inside the output shaft 6, it becomes possible to perform abnormality detection and connection release with a single electric actuator, and it is possible to install the electric actuator without requiring special assembly work necessary for connection release.

[0076] In addition, by providing a connecting portion 5C that can reversibly connect and disconnect the linear motion device 5 and the output shaft 6, the operation of the electric actuator can be invalidated according to the state of the electric actuator without destroying the components of the electric actuator, or the components of the electric actuator can be replaced without destroying them. Without replacing the components of the electric actuator, the operation of the electric actuator can be enabled according to the state of the electric actuator, and it becomes possible to improve the safety, efficiency, comfort, etc. during the use of the electric actuator.

[0077] In FIG. 1, an example in which the connection control unit 15 is provided in the control device 1 is shown, but the connection control unit 15 may be provided outside the control device 1. For example, it may be provided in a host device provided above the control device 1, or may be provided in the connecting portion 5C.

[0078] FIG. 2 is a block diagram showing an example of the hardware configuration of the data processing unit used in the control device of FIG. 1. In FIG. 2, the data processing unit 100 includes a processor 101, a communication control device 102, a communication interface 103, a main memory device 104, an auxiliary storage device 105, and an input / output interface 107. The processor 101, the communication control device 102, the communication interface 103, the main memory device 104, the auxiliary storage device 105, and the input / output interface 107 are mutually connected via an internal bus 106. The main memory device 104 and the auxiliary storage device 105 are accessible from the processor 101.

[0079] In addition, outside the data processing unit 100, an inverter 111, a sensor 112, an input device 113, an output device 114, and a connecting mechanism 115 are provided. The inverter 111, the sensor 112, the input device 113, the output device 114, and the connecting mechanism 115 are connected to the internal bus 106 via the input / output interface 107. The input device 113 and the output device 114 can be used as a human interface.

[0080] The input device 113 is, for example, a keyboard, a mouse, a touch panel, a card reader, a voice input device, or the like. The output device 114 is, for example, a screen display device (liquid crystal monitor, organic EL (Electro Luminescence) display, graphics card, etc.), a voice output device (speaker, etc.), a printing device, or the like.

[0081] The inverter 111 generates a drive current for the motor 2 based on a command from the processor 101. At this time, the inverter 111 can, for example, perform PWM (Pulse Width Modulation) control on the motor 2. The sensor 112 detects the state of the motor 2, the state of the linear motion device 5, and the state of the output shaft 6 in FIG. 1. The sensor 112 is, for example, the rotational position sensor 2A, the current sensor 13, and the sensor 7 in FIG. 1. The connection mechanism 115 connects or disconnects the linear motion device 5 and the output shaft 6 based on a command from the processor 101. The connection mechanism 115 can be used as the connection portion 5C in FIG. 1.

[0082] The processor 101 is hardware that controls the operation of the entire data processing unit 100. The processor 101 may be a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The processor 101 may be a single-core processor or a multi-core processor. The processor 101 may include a hardware circuit such as an accelerator that performs part of the processing (for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit)). The processor 101 may operate as a neural network.

[0083] The main memory device 104 can be composed of a semiconductor memory such as SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory), for example. In the main memory device 104, it is possible to store a program being executed by the processor 101 or provide a work area for the processor 101 to execute the program.

[0084] The auxiliary storage device 105 is a storage device having a large storage capacity, such as a hard disk device or an SSD (Solid State Drive), for example. The auxiliary storage device 105 can hold execution files of various programs and data used for program execution. The state detection program 105A and the connection control program 105B can be stored in the auxiliary storage device 105. The state detection program 105A and the connection control program 105B may be software installable in the data processing unit 100 or may be incorporated as firmware in the data processing unit 100.

[0085] The communication control device 102 is hardware having a function of controlling communication with the outside. The communication control device 102 is connected to the network 109 via the communication interface 103. The network 109 may be the Internet or a WAN (Wide Area Network), or may be a LAN (Local Area Network) such as WiFi or Ethernet (registered trademark), or may be a mixture of the Internet, WAN, and LAN.

[0086] The input / output interface 107 converts data input from the sensor 112 and the input device 113 into a data format processable by the processor 101, or converts data output from the processor 101 into a data format processable by the inverter 111, or into a data format processable by the output device 114, or into a data format processable by the connection mechanism 115.

[0087] The processor 101 reads the state detection program 105A into the main memory device 104 and executes the state detection program 105A, thereby detecting an abnormal state of the power unit 9 based on the signal converted by the power unit 9 in FIG. 1 or the detection values before and after the conversion of the motion. For example, the processor 101 can calculate an estimated value estimated as the state of the output shaft 6 based on the detection value of the state of the motor 2. Then, the processor 10 can detect an abnormal state of the power unit 9 based on the comparison result between the detection value of the state of the output shaft 6 and the estimated value estimated as the state of the output shaft 6 from the detection value of the state of the motor 2. At this time, the processor 101 can obtain the detection values before and after the conversion from the sensor 112.

[0088] Further, the processor 101 reads the connection control program 105B into the main memory device 104 and executes the connection control program 105B to obtain the detection result detected by the state detection program 105A. When the detection result detected by the state detection program 105A indicates an abnormal state of the power unit 9, the processor 101 causes the connection between the linear motion device 5 and the output shaft 6 to be released via the connection mechanism 115. Then, when the abnormal state of the power unit 9 is released, the processor 101 connects the linear motion device 5 and the output shaft 6 via the connection mechanism 115. For example, when the motor 2 is in a normal state, the processor 101 can issue a connection release signal Sr instructing the release of the connection between the linear motion device 5 and the output shaft 6 based on the detection value of the state of the output shaft 6. Further, the control device 1 can calculate an estimated value that is the estimated state of the output shaft 6 based on the detection value of the output state of the motor 2, and issue a connection release signal Sr instructing the release of the connection between the linear motion device 5 and the output shaft 6 based on the estimated value and the detection value of the state of the output shaft 6.

[0089] Note that the execution of the state detection program 105A and the connection control program 105B may be shared among a plurality of processors or computers. Alternatively, the processor 101 may instruct a cloud computer or the like via the network 109 to execute all or part of the state detection program 105A and the connection control program 105B, and receive the execution results.

[0090] This data processing unit 100 can be provided in the control device 1 of FIG. 1. At this time, the data processing unit 100 can undertake functions realized by software or firmware in the control device 1.

[0091] FIG. 3 is a flowchart showing an example of the abnormality detection process of the electric actuator of FIG. 1. Each step in FIG. 3 is realized by the processor 101 reading and executing the program stored in the auxiliary storage device 105 of FIG. 2. At this time, the processor 101 in FIG. 2 can function as the abnormality detection unit 14 and the connection control unit 15 in FIG. 1.

[0092] In FIG. 3, the processor 101 in FIG. 2 acquires the detected value of the drive current of the motor 2 in FIG. 1 from the current sensor 13 (S11). Next, the processor 101 acquires the detected value of the position of the output shaft 6 from the sensor 7 (S12). At this time, a position sensor can be used as the sensor 7.

[0093] Next, the processor 101 calculates an estimated value of the axial force of the output shaft 6 based on the detected value of the drive current of the motor 2 acquired in S11 (S13). At this time, the processor 101 can calculate the estimated value of the axial force based on, for example, an expression such as drive current × motor coefficient × gear ratio of the speed reducer × movement amount of the ball screw.

[0094] Next, the processor 101 determines whether the estimated value of the axial force of the output shaft 6 is equal to or greater than a certain value and whether the detected value of the position of the output shaft 6 has not changed for a certain period of time (S14). If the condition that the estimated value of the axial force of the output shaft 6 is equal to or greater than a certain value and the detected value of the position of the output shaft 6 has not changed for a certain period of time is not satisfied, the processor 101 returns to the process of S11. On the other hand, when the condition that the estimated value of the axial force of the output shaft 6 is equal to or greater than a certain value and the detected value of the position of the output shaft 6 has not changed for a certain period of time is satisfied, the processor 101 releases the connection between the linear actuator 5 and the output shaft 6 via the connecting portion 5C (S15).

[0095] Thereby, while enabling the processor 101 to control the position of the output shaft 6 based on the drive current of the motor 2, by detecting the drive current of the motor 2 and the position of the output shaft 6, it is possible to detect an abnormal state of the transmission system up to the output shaft 6 beyond the motor. For this reason, while aiming for higher accuracy and efficiency in the abnormal analysis of the electric actuator, it becomes possible to control the connection of the connecting portion 5C, and it becomes possible to improve the safety, efficiency, and comfort when using the electric actuator.

[0096] Also, by performing a simple calculation based on the detection results of the drive current of the motor 2 and the position of the output shaft 6, it is possible to detect a stuck state of the power transmission system up to the output shaft 6 beyond the motor 2, and while suppressing an increase in the load of the control system of the electric actuator, it becomes possible to achieve higher accuracy and efficiency in the connection control of the connecting portion 5C.

[0097] Also, by also using the current sensor 13 used for motor control as a sensor for detecting abnormalities, it becomes possible to detect an abnormal state of the power unit 9 without separately providing a current sensor for detecting abnormalities. For this reason, while suppressing an increase in size and cost of the electric actuator, it becomes possible to achieve higher accuracy and efficiency in the abnormal analysis.

[0098] FIG. 4 is a flowchart showing another example of the abnormality detection process of the electric actuator of FIG. 1. Here, the processor 101 can implement the process of FIG. 4 by executing a program that implements the process of FIG. 4 instead of the program that implements the process of FIG. 3.

[0099] In FIG. 4, the processor 101 of FIG. 2 acquires the detected value of the drive current of the motor 2 of FIG. 1 from the current sensor 13 (S21). Next, the processor 101 acquires the detected value of the position of the output shaft 6 from the sensor 7 (S22). At this time, a position sensor can be used as the sensor 7.

[0100] Next, the processor 101 determines whether the detected value of the drive current is equal to or greater than a certain value and whether the amount of change in the detected value of the position of the output shaft 6 within a certain period of time is equal to or less than a certain value (S23). And when the condition that the detected value of the drive current is equal to or greater than a certain value and the amount of change in the detected value of the position of the output shaft 6 within a certain period of time is equal to or less than a certain value is not satisfied, the processor 101 returns to the process of S21. On the other hand, when the condition that the detected value of the drive current is equal to or greater than a certain value and the amount of change in the detected value of the position of the output shaft 6 within a certain period of time is equal to or less than a certain value is satisfied, the connection between the linear motion device 5 and the output shaft 6 is released via the connecting portion 5C (S24).

[0101] Thereby, while the processor 101 can control the position of the output shaft 6 based on the drive current of the motor 2, by detecting the drive current of the motor 2 and the position of the output shaft 6, it is possible to detect an abnormal state of the transmission system from the motor to the output shaft 6. For this reason, while achieving higher accuracy and efficiency in the abnormality analysis of the electric actuator, it becomes possible to control the connection of the connecting portion 5C, and it becomes possible to improve the safety, efficiency, and comfort when using the electric actuator.

[0102] Further, by performing a simple calculation based on the detection results of the drive current of the motor 2 and the position of the output shaft 6, it is possible to detect the stuck state of the power transmission system up to the output shaft 6 beyond the motor 2, and while suppressing an increase in the load of the control system of the electric actuator, it becomes possible to improve the accuracy and efficiency of the connection control of the connecting portion 5C.

[0103] FIG. 5 is a flowchart showing still another example of the abnormality detection process of the electric actuator of FIG. 1. Here, the processor 101 can realize the process of FIG. 5 by executing a program that realizes the process of FIG. 5 instead of the programs that realize the processes of FIGS. 3 and 4.

[0104] In FIG. 5, the processor 101 of FIG. 2 acquires the detected value of the drive current of the motor 2 of FIG. 1 from the current sensor 13 (S31). Next, the processor 101 acquires the detected value of the rotational position of the motor 2 from the rotational position sensor 2A (S32).

[0105] Next, the processor 101 determines whether the detected value of the drive current is equal to or greater than a certain value and whether the amount of change in the detected value of the rotational position of the motor 2 within a certain time is equal to or less than a certain value (S33). And when the processor 101 does not satisfy the condition that the detected value of the drive current is equal to or greater than a certain value and the amount of change in the detected value of the rotational position of the motor 2 within a certain time is equal to or less than a certain value, it returns to the process of S31. On the other hand, when the processor 101 satisfies the condition that the detected value of the drive current is equal to or greater than a certain value and the amount of change in the detected value of the rotational position of the motor 2 within a certain time is equal to or less than a certain value, it releases the connection between the linear motion device 5 and the output shaft 6 via the connecting portion 5C (S34).

[0106] Thereby, the processor 101 can detect the abnormal state of the motor 2 by detecting the drive current and the rotational position of the motor 2 while enabling control of the rotational position of the motor 2 based on the drive current of the motor 2. For this reason, while improving the accuracy and efficiency of the abnormality analysis of the electric actuator, it becomes possible to perform connection control of the connecting portion 5C, and it becomes possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0107] Also, by performing a simple calculation based on the detection results of the drive current and the rotational position of the motor 2, an abnormal state of the motor 2 can be detected. Therefore, while suppressing an increase in the load of the control system of the electric actuator, it is possible to improve the accuracy and efficiency of the connection control of the connecting portion 5C, and it is possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0108] Also, by using the rotational position sensor 2A used for motor control also as a sensor for detecting abnormalities, it is possible to detect an abnormal state of the motor 2 without separately providing a rotational position sensor for detecting abnormalities. Therefore, while suppressing an increase in size and cost of the electric actuator, it is possible to improve the accuracy and efficiency of abnormality analysis.

[0109] FIG. 6 is a flowchart showing still another example of the abnormality detection process of the electric actuator of FIG. 1. Here, the processor 101 can implement the process of FIG. 6 by executing a program that implements the process of FIG. 6 instead of the programs that implement the processes of FIGS. 3, 4, and 5.

[0110] In FIG. 6, the processor 101 of FIG. 2 acquires the detected value of the drive current of the motor 2 of FIG. 1 from the current sensor 13 (S41). Next, the processor 101 acquires the detected value of the axial force output from the output shaft 6 from the sensor 7 (S42). At this time, an axial force sensor can be used as the sensor 7.

[0111] Next, the processor 101 determines whether the detected value of the drive current is equal to or greater than a certain value and whether the axial force of the output shaft 6 is equal to or less than a certain value (S43). If the condition that the detected value of the drive current is equal to or greater than a certain value and the axial force of the output shaft 6 is equal to or less than a certain value is not satisfied, the processor 101 returns to the process of S41. On the other hand, when the condition that the detected value of the drive current is equal to or greater than a certain value and the axial force of the output shaft 6 is equal to or less than a certain value is satisfied, the processor 101 releases the connection between the linear motion device 5 and the output shaft 6 via the connecting portion 5C (S44).

[0112] Thereby, the processor 101 can detect an abnormal state of the transmission system up to the output shaft 6 beyond the motor by detecting the drive current of the motor 2 and the axial force of the output shaft 6 while enabling control of the axial force of the output shaft 6 based on the drive current of the motor 2. For this reason, while aiming for higher accuracy and efficiency in the abnormality analysis of the electric actuator, it becomes possible to control the connection of the connecting portion 5C, and it becomes possible to improve the safety, efficiency, comfort, etc. when using the electric actuator.

[0113] Also, by performing a simple calculation based on the detection results of the drive current of the motor 2 and the axial force of the output shaft 6, it is possible to detect a stuck state of the power transmission system up to the output shaft 6 beyond the motor 2, and while suppressing an increase in the load of the control system of the electric actuator, it becomes possible to achieve higher accuracy and efficiency in the connection control of the connecting portion 5C.

[0114] FIG. 7 is a flowchart showing still another example of the abnormality detection process of the electric actuator of FIG. 1. Here, the processor 101 can implement the process of FIG. 7 by executing a program that implements the process of FIG. 7 instead of the program that implements the processes of FIGS. 3 to 6.

[0115] In FIG. 7, the processor 101 of FIG. 2 acquires the detected value of the rotational position of the motor 2 from the rotational position sensor 2A (S51). Next, the processor 101 acquires the detected value of the position of the output shaft 6 from the sensor 7 (S52). At this time, a position sensor can be used as the sensor 7. Next, the processor 101 calculates an estimated value of the linear movement position of the linear actuator 5 based on the detected value of the rotational position of the motor 2 acquired in S51 (S53).

[0116] Next, the processor 101 determines whether the difference between the estimated value of the linear movement position of the linear actuator 5 and the detected value of the position of the output shaft 6 is greater than or equal to a certain value and the change amount within a certain time is less than or equal to a certain value (S54). When the condition that the difference between the estimated value of the linear movement position of the linear actuator 5 and the detected value of the position of the output shaft 6 is greater than or equal to a certain value and the change amount within a certain time is less than or equal to a certain value is not satisfied, the processor 101 returns to the process of S51. On the other hand, when the condition that the difference between the estimated value of the linear movement position of the linear actuator 5 and the detected value of the position of the output shaft 6 is greater than or equal to a certain value and the change amount within a certain time is less than or equal to a certain value is satisfied, the processor 101 releases the connection between the linear actuator 5 and the output shaft 6 via the connecting portion 5C (S55).

[0117] Thereby, while enabling the processor 101 to control the linear movement of the linear actuator 5 based on the rotational movement of the motor 2, by detecting the rotational position of the motor 2 and the position of the output shaft 6, it is possible to detect an abnormal state of the transmission system up to the output shaft 6 beyond the motor 2. For this reason, while aiming for higher accuracy and efficiency in the abnormality analysis of the electric actuator, it becomes possible to control the connection of the connecting portion 5C, and it becomes possible to improve the safety, efficiency, comfort, etc. during the use of the electric actuator.

[0118] Also, by performing a simple calculation based on the drive current of the motor 2 and the detection result of the position of the output shaft 6, it is possible to detect a stuck state of the power transmission system up to the output shaft 6 beyond the motor 2, and while suppressing an increase in the load of the control system of the electric actuator, it becomes possible to achieve higher accuracy and efficiency in the connection control of the connecting portion 5C.

[0119] Note that the processor 101 may execute at least two of the processes shown in FIGS. 3 to 7 in parallel. At this time, if an abnormality is detected in at least one of the processes shown in FIGS. 3 to 7, the electric actuator may be determined to be abnormal. Thereby, even when the rotational position sensor 2A, the current sensor 13, or the axial force sensor or position sensor used as the sensor 7 malfunctions, it is possible to determine the abnormality of the electric actuator, and the robustness of the electric actuator can be improved.

[0120] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, it is possible to add, delete, or replace with other configurations.

[0121] For example, in the above-described embodiment, the case where the sensor 7 for detecting the state of the output shaft 6 is directly installed on the output shaft 6 is shown. However, as the sensor 7, for example, a remote sensor or a non-contact sensor such as an infrared sensor, an ultrasonic sensor, or an image sensor may be used.

[0122] Also, in the above-described embodiment, an example of detecting an abnormality of the electric actuator based on the detected value of the state of the motor 2 and the detected value of the state of the output shaft 6 is shown. However, instead of the detected value of the state of the motor 2 or the detected value of the state of the output shaft 6, the detected value of the state of the linear actuator 5 may be used. The detected value of the state of the linear actuator 5 may be, for example, the detected value of the input torque of the linear actuator 5 or the detected value of the linear position of the linear actuator 5. To detect the input torque of the linear actuator 5, for example, a torque sensor such as a strain gauge may be installed on the gear of the speed reducer 3C. To detect the linear position of the linear actuator 5, a rotational position sensor of the screw shaft 5A or a position sensor of the nut 5B may be installed on the linear actuator 5.

Description of Reference Numerals

[0123] 1 Control device, 2 Motor, 3A - 3C Reducer, 4 Bearing, 5 Linear motion device, 5A Screw shaft, 5B Nut, 5C Connecting part, 6 Output shaft, 7 Sensor, 9 Power unit, 11 Motor control unit, 12 Motor angle calculation unit, 13 Current sensor, 14 Abnormality detection unit, 15 Connection control unit

Claims

1. A drive source that generates power, An output member that is driven via an intermediate member according to the output state of the drive source, A coupling portion capable of reversibly coupling and decoupling the intermediate member and the output member, A first sensor that detects the output state of the drive source, A second sensor that detects the state of the output member, A control unit that commands decoupling of the intermediate member and the output member based on the detection value of the first sensor and the detection value of the second sensor, The control unit includes an estimation unit that calculates an estimated value, which is the estimated state of the output member, based on the detection value of the first sensor, When the control unit detects that the estimated value is equal to or greater than a predetermined value and the detection value of the second sensor does not change for a predetermined time, the control unit issues a decoupling signal, The coupling portion is characterized in that it decouples the intermediate member and the output member based on a decoupling signal from the control unit. An electric actuator. comprising,

2. The control unit, When an abnormality in the transmission system from the drive source to the output member is detected, the control unit causes the intermediate member and the output member to be decoupled, When the transmission system is normal, the electric actuator according to claim 1, wherein the intermediate member and the output member are coupled.

3. The control unit commands decoupling of the intermediate member and the output member based on at least any two detection values of the detection value of the state of the drive source, the detection value of the state of the intermediate member, and the detection value of the state of the output member. The electric actuator according to claim 1 or 2.

4. The drive source includes a motor, The intermediate member includes a linear motion device that converts the rotational motion input from the motor into a linear motion, The output member includes an output shaft that outputs an axial force based on the linear motion converted by the linear motion device. When the control unit detects that the estimated value is equal to or greater than a predetermined value and the detected value of the second sensor does not change for a predetermined time, the control unit issues a connection release signal for instructing the disconnection between the linear motion device and the output shaft. The electric actuator according to any one of claims 1 to 3, characterized in that.

5. A motor that generates power, It is driven by a linear motion device that converts the rotational motion input from the motor into linear motion, and includes an output shaft that outputs an axial force based on the linear motion converted by the linear motion device, A connecting portion capable of reversibly connecting and disconnecting the linear motion device and the output shaft, Based on the estimated value of the axial force of the output shaft estimated from the detected value of the drive current of the motor and the detected value of the position of the output shaft, a control unit that issues a connection release signal for instructing the disconnection between the linear motion device and the output shaft, The control unit issues the connection release signal when the estimated value of the axial force is equal to or greater than a certain value and the detected value of the position of the output shaft does not change for a certain time. The electric actuator is characterized by this.

6. The control unit issues the connection release signal based on the detected value of the drive current of the motor and the detected value of the position of the output shaft. The electric actuator according to claim 4 or 5, characterized in that.

7. The control unit issues the connection release signal when the detected value of the drive current of the motor is equal to or greater than a certain value and the amount of change in the detected value of the position of the output shaft within a certain time is equal to or less than a certain value. The electric actuator according to claim 6, characterized in that.

8. The control unit issues the connection release signal based on the detected value of the drive current of the motor and the detected value of the rotational position of the motor. The electric actuator according to any one of claims 4 to 7, characterized in that.

9. The control unit issues the connection release signal when a detected value of a drive current of the motor is equal to or greater than a certain value and a change amount of a detected value of a rotational position of the motor within a certain period of time is equal to or less than a certain value. The electric actuator according to claim 8, characterized in that.

10. The control unit issues the connection release signal based on a detected value of a drive current of the motor and a detected value of an axial force of the output shaft. The electric actuator according to any one of claims 4 to 9, characterized in that.

11. The control unit issues the connection release signal when a detected value of a drive current of the motor is equal to or greater than a certain value and a detected value of an axial force of the output shaft is equal to or less than a certain value. The electric actuator according to claim 10, characterized in that.

12. The control unit detects a state of a transmission system from the drive source to the output member based on an estimated value of a linear motion position of the linear motion device estimated from a detected value of a rotational position of the motor and a detected value of a position of the output shaft. The electric actuator according to any one of claims 4 to 11, characterized in that.

13. The control unit issues the connection release signal when a difference between the estimated value of the linear motion position of the linear motion device and the detected value of the position of the output shaft is equal to or less than a certain value and a change amount within a certain period of time is equal to or less than a certain value. The electric actuator according to claim 12, characterized in that.

14. The control unit further includes a motor control unit that controls the motor based on a detected value of a drive current of the motor and a detected value of a rotational position of the motor. The electric actuator according to any one of claims 4 to 13, characterized in that.

15. The electric actuator according to any one of claims 1 to 14, characterized in that it is applied to a vibration damping device.

16. A motor control unit that controls a motor that drives a linear motion device connected to an output shaft, A connection control unit that controls the connection between the linear motion device and the output shaft based on the detection value of a first sensor that detects the output state of the motor and the detection value of a second sensor that detects the state of the output shaft. The connection control unit includes an estimation unit that calculates an estimated value, which is the estimated state of the output shaft, based on the detection value of the first sensor. The connection control unit is characterized in that when it detects that the estimated value is equal to or greater than a predetermined value and the detection value of the second sensor does not change for a predetermined time, it issues a connection release signal to release the connection between the linear motion device and the output shaft.

17. A motor control unit that controls a motor that drives a linear motion device connected to an output shaft, Based on the estimated value of the axial force of the output shaft estimated from the detected value of the drive current of the motor and the detected value of the position of the output shaft, when the estimated value of the axial force is equal to or greater than a certain value and the detected value of the position of the output shaft does not change for a certain time, a connection release signal is issued to release the connection between the linear motion device and the output shaft. A control device characterized by this.

18. Steps of obtaining the detection value of a first sensor that detects the output state of a motor that drives a linear motion device connected to an output shaft, Steps of obtaining the detection value of a second sensor that detects the state of the output shaft, Steps of calculating an estimated value, which is the estimated state of the output shaft, based on the detection value of the first sensor, Steps of causing a computer to execute, when it detects that the estimated value is equal to or greater than a predetermined value and the detection value of the second sensor does not change for a predetermined time, issuing a connection release signal to release the connection between the linear motion device and the output shaft. A control program characterized by this.

19. Steps of estimating the axial force of the output shaft from the detected value of the drive current of a motor that drives a linear motion device connected to the output shaft, Steps of obtaining the detected value of the position of the output shaft, A control program characterized by causing a computer to execute a step of issuing a disconnection signal to disconnect the linear motion device from the output shaft when, based on the estimated value of the axial force of the output shaft and the detected value of the position of the output shaft, the estimated value of the axial force is equal to or greater than a certain value and the detected value of the position of the output shaft does not change for a certain period of time.

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