Control device and control method for actuator device

Abstract

To realize more precise control of an actuator device based on a static frictional force taking into account an equilibrium of force.SOLUTION: A control device for an actuator device that operates using a motor, comprises: a disturbance observer; disturbance torque estimating means for estimating a disturbance torque for the actuator device by using an intermediate parameter of the disturbance observer and a Kalman filter; and reaction force estimation means for estimating a reaction force acting on the actuator device based on a model in which the disturbance torque estimated by the disturbance torque estimation means, the motor torque, the static friction, and the reaction force are in balance.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device and a control method for an actuator device. [Background technology]

[0002] Conventionally, actuator devices driven by motors are used in various mechanical devices. In the actuator devices, reaction force estimation and force control are performed when the actuator devices are operated. Specific examples of mechanical devices to which the actuator devices can be applied include transport equipment for plastic products, haptic devices, and nursing care robots.

[0003] For example, Patent Document 1 discloses a configuration in which the load applied to the actuator is estimated as a reaction force by an observer, and the influence of the frictional force contained therein is eliminated by using a previously identified maximum static frictional force of the actuator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-187099 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the method of Patent Document 1, control is performed based on the maximum static friction force. In such a configuration, the timing when the actual friction force and the identified maximum static friction force match is only the moment when the actuator transitions from a stopped state to a moving state. In other words, it is not possible to take into account the friction force in a stopped state or at the moment when the actuator transitions from a moving state to a stopped state. Therefore, for example, it is difficult to accurately estimate the reaction force only from the maximum static friction as in Patent Document 1.

[0006] A specific mechanical device will be considered for explanation. For example, in a conveying device for plastic products, when gripping plastic or conveying the plastic container while maintaining the gripped state, the force that the gripping actuator device can output is large compared to the force required to grip the plastic container. In such a case, if an excessive force is applied from the actuator device to the plastic container to be gripped, the plastic container will be deformed or damaged. On the other hand, if the gripping force is small, the plastic container will fall during conveyance.

[0007] Furthermore, haptic devices are worn on a person's finger and used as devices for transmitting force and tactile sensations to a person, for example, by being incorporated into a controller unit of a remote-controlled robot. In such a configuration, an actuator device is used to present the force that the remote-controlled robot is applying to an object to a user of the haptic device. In this case, if the force that the remote-controlled robot is applying to the object cannot be accurately presented to the user, the operator cannot appropriately adjust the amount of operation, and as a result, there is a possibility that the remote-controlled robot will destroy the object.

[0008] Nursing robots are also used to care for and assist the elderly and injured, for example. When transferring an elderly person from a bed to a wheelchair, the nursing robot must hold the elderly person without causing pain or anxiety. If the force applied to the care recipient cannot be accurately adjusted, not only will the care recipient feel pain and anxiety, but there is also a possibility that a large force that could injure the care recipient may be applied.

[0009] As described above, in various devices to which an actuator device is applied, it is required to appropriately control the force that the actuator device exerts, i.e., the force that the actuator device applies to an object, taking into consideration the purpose and usage of the device, etc. To achieve this, it is necessary to accurately estimate the reaction force acting on the actuator device when the actuator device operates.

[0010] In view of the above-mentioned problems, an object of the present invention is to realize more accurate control of an actuator device based on static friction force taking into account the balance of forces. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention has the following configuration. That is, a control device for an actuator device that operates using a motor, comprising: A disturbance observer; a disturbance torque estimating means for estimating a disturbance torque applied to the actuator device by using an intermediate parameter of the disturbance observer and a Kalman filter; a reaction force estimation means for estimating a reaction force acting on the actuator device based on the disturbance torque estimated by the disturbance torque estimation means and a model of a state in which a motor torque, static friction, and a reaction force are in balance; A control device comprising:

[0012] Another aspect of the present invention has the following configuration. That is, a method for controlling an actuator device that operates using a motor, comprising the steps of: a disturbance torque estimating step of estimating a disturbance torque for the actuator device using intermediate parameters of a disturbance observer and a Kalman filter; a reaction force estimation step of estimating a reaction force acting on the actuator device based on the disturbance torque estimated in the disturbance torque estimation step and a model of a state in which a motor torque, static friction, and a reaction force are in balance; The control method includes: Effect of the Invention

[0013] According to the present invention, it is possible to realize more accurate control of the actuator device. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a configuration example of an actuator device according to an embodiment of the present invention; [Diagram 2]FIG. 2 is a block diagram showing a control configuration of the actuator device according to one embodiment of the present invention. [Diagram 3] FIG. 11 is a block diagram showing a control configuration of an actuator device according to another embodiment of the present invention. [Figure 4] FIG. 11 is a block diagram showing a control configuration of an actuator device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. Note that the embodiment described below is one embodiment for explaining the present invention, and is not intended to be interpreted as limiting the present invention, and all configurations described in each embodiment are not necessarily essential configurations for solving the problems of the present invention. In addition, in each drawing, the same components are given the same reference numbers to indicate their correspondence.

[0016] <First embodiment> A first embodiment of the present invention will be described below. Note that the configuration of a linear actuator device shown below is one example. The actuator control method according to this embodiment is applicable to various devices that perform motor control using reaction force estimation, such as a robot hand or a manipulator device, in addition to a linear actuator device. Therefore, the control method according to the present invention is not limited to the configuration described below, and can be applied to various devices equipped with an actuator device.

[0017] [Configuration overview] 1 is a block diagram showing an example of the configuration of a linear actuator device 100 to which an actuator control method according to one embodiment of the present invention can be applied. A controller 101 transmits a control signal to a motor 104 via a motor driver 102 to control the operation of the motor. The controller 101 also receives a detection signal from an encoder 103 installed on the motor 104 via the motor driver 102. The controller 101 may be configured, for example, by a dedicated control circuit or hardware, or may be configured as an information processing device such as a PC (Personal Computer).

[0018] The controller 101 may be configured to include, for example, a processor and peripheral components such as a storage device. The processor may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage device may include, for example, any one of a semiconductor storage device, a magnetic storage device, and an optical storage device. The storage device may include a register, a cache memory, and a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory) used as a main storage device.

[0019] When the controller 101 is configured as a dedicated circuit, the controller 101 may include a functional logic circuit configured in a general-purpose semiconductor integrated circuit. For example, the controller 101 may include a programmable logic device (PLD) such as a field programmable gate array (FPGA).

[0020] The motor driver 102 performs input / output control of current, such as phase control and switching control, for the motor 104, based on a control signal from the controller 101. The motor driver 102 also notifies the controller 101 of a detection signal detected by the encoder 103. The encoder 103 detects a state associated with the operation of the motor 104, and transmits the state as a detection signal to the controller 101 via the motor driver 102. In this embodiment, the encoder 103 detects a motor angle θ of the motor 104, and provides the motor angle θ to the controller 101.

[0021] The motor 104 is connected to a single-axis linear actuator unit via a motor bearing 105 and a coupling 106, and is configured to be able to transmit its rotational motion. A ball screw shaft 107 connected to the motor 104 is rotatably supported by ball screw bearings 108 and 109 in the actuator unit. The ball screw shaft 107, which can rotate together with the rotational motion of the motor 104, rotates, whereby a nut 110 moves in a predetermined direction along a linear guide 111, and a stage 112 and a tip part 113 also move in the predetermined direction together with the nut 110. The linear guide 111 is provided on the stage 112, and the movement of the stage 112 is restricted to a predetermined direction (a direction parallel to the axial direction of the ball screw shaft).

[0022] The tip part 113 is used for the manipulation of an object (not shown) and is configured to come into contact with the object. In the example of FIG. 1, when the tip part 113 comes into contact with the object in a predetermined direction, a force F ext Here, the force acting along the moving direction of the tip part 113 is represented as force F acting on the tip part 113. ext In the following description, the side of the tip part 113 from the motor 104 may be collectively referred to as the linear actuator part side.

[0023] [Control configuration] 2 is a block diagram showing an example of the configuration around the control configuration of the linear actuator device 100 according to one embodiment of the present invention. Here, the description focuses on a part of the configuration. First, the parameters shown in each figure are defined as follows.

[0024]

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[0026] In this embodiment, a disturbance observer 217, a Kalman filter 215, and a reaction force estimation unit 216 are implemented in the controller 101. In Fig. 2, for the sake of convenience, various parameters (reference numbers 203 to 207) are shown on the side of the motor 104 and the linear actuator unit connected thereto.

[0027] The current converter 201 converts the motor angular acceleration command value θ ··ref J an and K. tn Based on the current command value i a ref (=u). u is input to the Kalman filter 215. The adder 202 converts the current command value i a ref The disturbance estimate (current estimate) by the disturbance observer 217 is added to the current command value i a ref The motor driver 102 is omitted here. The corrected current command value i a ref ' and motor torque coefficient K t Motor torque T based on M and disturbance torque T d The combined force is transmitted to the linear actuator unit side including the ball screw shaft 107.

[0028] On the linear actuator side, the resultant torque and equivalent inertia J a These appear as the motor angle, motor angular velocity, and motor angular acceleration. Although omitted in Fig. 2, in this embodiment, the motor angle θ of the motor 104 is detected by the encoder 103, and the motor angular velocity of the motor 104 is derived and used by differentiating the motor angle θ. The derived motor angular velocity is output to the Kalman filter 215.

[0029] In the disturbance observer 217, the corrected current command value i a ref ' with respect to the motor torque coefficient K tn The torque value obtained by multiplying the motor angular velocity θ · For J an and ω Q The result (acceleration / deceleration torque value) obtained by multiplying the acceleration / deceleration torque value by the adder 209 is combined to obtain a combined value. Further, the combined value is filtered by the low-pass filter 211 to obtain x Q Derive x Q For convenience, we also call it an intermediate parameter. This intermediate parameter x Q is output to the Kalman filter 215. Furthermore, the subtractor 213 outputs x Q From the motor angular velocity, J an and ω Q The disturbance torque estimate -T^ is calculated by subtracting the result (acceleration / deceleration torque value) obtained by multiplying d This torque estimate -T^ is derived. d is converted to a current value by the current converter 212 and fed back to obtain the corrected current command value i a ref This derives the disturbance torque T d can be cancelled.

[0030] In this embodiment, the above θ · , x Q , u are input to a Kalman filter 215 to derive an estimate of the state vector. Since the Kalman filter is a known technique, detailed description will be omitted, but it is configured as follows.

[0031] First, the state equation and the observation equation y as the state space representation of the system are defined as follows:

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[0035] As a preliminary step, we will ignore each noise and discretize the system based on equation (1) as shown in equation (6). Here, the subscript d indicates the discretized matrix, and the subscript k indicates the signal at discretization time k.

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[0037] k is an integer value, and the sampling period T s If it is discretized in [s], T s The value of k is specified for each T s = 0.1 [s], time t = k × T s =k×0.1[s] (k=0,1,···,n).

[0038] In the Kalman filter 215, the following five steps are performed in one sampling period (=T s ) are executed sequentially.

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[0045] By using the above-mentioned Kalman filter, a value equivalent to the torque value is obtained as an output value.

[0046] Furthermore, the reaction force estimation unit 216 estimates the reaction force on the linear actuator device 100 using the output value x^ from the Kalman filter 215. In the configuration of the linear actuator device 100 shown in FIG. 1, the equation of motion and disturbance torque can be defined as the following equations (12) to (15). As shown in equation (13), the disturbance torque T d is the sum of the friction torque and the reaction torque.

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[0051] In the linear actuator device 100, the force and torque input to the ball screw shaft, which is the main friction element, is the motor torque T M and reaction torque T ext This resultant force is rewritten into an equation that explicitly shows this resultant force. At the same time, viscous resistance -D a θ · also exists, so this is taken into consideration and defined as the following equations (16) and (17). The following equations are defined based on the Karnopp model, which is a known friction model. Note that the sign function indicates whether the variable is positive or negative.

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[0055] The fact that the relationship between the disturbance torque, friction torque, and reaction torque is expressed by the above formulas (16) and (17) for the state of the linear actuator device 100 is utilized. In addition, as shown in the following formulas (18) to (20), the inertial force J a θ ·· will also be compensated.

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[0059] Combining equations (16) to (20), the reaction torque estimate T^ ext is defined as follows:

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[0061] In the case of the above formula (18) and formula (20), the current (k) reaction torque estimate is calculated regardless of the previous (k-1) reaction torque estimate. In other words, the previous (k-1) disturbance torque estimate T^ d In the case of the above equation (19), since it is a differential equation related to the reaction torque estimate, it can be regarded as a dynamic system based on the previous (k-1) reaction torque estimate.

[0062] Then, it becomes possible to control the operation of the linear actuator device 100 based on the reaction torque estimated by the reaction torque estimator 216 based on the above equations. For example, the motor angular acceleration command value θ ··ref It becomes possible to adjust the value of

[0063] As described above, this embodiment allows for more accurate estimation of the reaction force compared to control based only on the maximum static friction. This allows for more precise control of the actuator device. For example, more precise control is possible when controlling the actuator device according to the device and its usage conditions, such as in the above-mentioned transport equipment, force contact devices, and nursing care robots to which the actuator device can be applied.

[0064] <Second embodiment> A second embodiment of the present invention will be described. When a motor performs a rotational operation, fluctuations in output torque during the rotation may occur. These fluctuations are known as torque ripples, and affect the operability and operational accuracy of the actuator device. In the second embodiment of the present invention, a form will be described in which an estimated value of disturbance torque is derived taking into account the torque ripples generated in the motor 104. Note that the device configuration is similar to the configuration of FIG. 1 described in the first embodiment, and therefore a description thereof will be omitted here.

[0065] 3 is a block diagram showing the control according to the present embodiment. As shown in FIG. 3, in the motor 104, the motor torque T M Torque ripple T r and a composite value of these is transmitted to the linear actuator section side. In Fig. 3, for convenience, various parameters (reference numbers 301 to 306) are shown on the motor 104 and the linear actuator section side connected thereto. Also, in Fig. 3, attention is focused on the disturbance torque estimator 311 according to this embodiment, and the configuration of a reaction force estimator and the like is omitted.

[0066] In the disturbance torque estimator 311, u, torque ripple T r The nominal value of T rn , motor angular velocity θ · The motor angular velocity θ · For J an From the value obtained by multiplying and s (torque value), T rn Torque ripple T r The nominal value of T rn may be derived in advance. Furthermore, the subtractor 308 subtracts K tn The torque value multiplied by is subtracted from this value. By applying the LPF 310 to this value, the disturbance torque estimate T^ with the torque ripple removed is obtained. d This disturbance torque estimate T^ is derived. d Using this, feedback and reaction force estimation in the disturbance observer can be performed. The reaction force estimation method is the same as in the first embodiment. As in the disturbance observer shown in FIG. 2, D=0, L=ωQ J a Then, the configuration of the disturbance torque estimator 311 shown in FIG. 3 can be defined by the following equation (22).

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[0068] (Modification) FIG. 4 is a block diagram showing a modified example of the second embodiment. Here, an example is shown in which a disturbance observer 419 and a disturbance torque estimator 420 are connected in parallel. The disturbance observer 419 has a configuration equivalent to that of the disturbance observer 217 shown in FIG. 2. Moreover, the disturbance torque estimator 420 has a configuration equivalent to that of the disturbance torque estimator 311 shown in FIG. 3. In this case as well, the disturbance torque estimator 420 calculates a disturbance torque estimated value T^ from which torque ripple has been removed in the same manner as in FIG. 3. d In addition, similarly to FIG. 2, feedback is performed by the disturbance observer 419 to derive the corrected current command value i a ref ' is generated.

[0069] As described above, according to this embodiment, in addition to the effects of the first embodiment, it is possible to estimate the reaction force more accurately by taking the torque ripple into consideration.

[0070] <Other embodiments> In the first embodiment, an example in which a linear Kalman filter is used has been shown. However, the present invention is not limited to this, and a non-linear Kalman filter may be used. In this case, the disturbance torque can be estimated while taking into account the non-linearity of the system, so that it is possible to further improve the accuracy of the reaction force estimation.

[0071] For example, the control of each of the above-described embodiments can be applied to a medical manipulator device. When operating a medical manipulator device, the user generally operates the device while visually checking the contact state. In such an operating environment, the reaction force associated with the contact can be more accurately estimated and fed back to the user, allowing the user to recognize the contact state tactilely. With this configuration, it is also possible to appropriately estimate contact with a relatively soft object.

[0072] In the present invention, a program or application for realizing the functions of one or more of the above-mentioned embodiments can be supplied to a system or device via a network or a storage medium, etc., and one or more processors in a computer of the system or device can read and execute the program, thereby making it possible to realize the present invention.

[0073] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates mutual combinations of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the descriptions in the specification and well-known technologies, and these are included in the scope of protection sought.

[0074] As described above, the present specification discloses the following: (1) A control device (e.g., 101) for an actuator device that operates using a motor (e.g., 104), A disturbance observer (e.g., 217) and The intermediate parameters of the disturbance observer (e.g., x Q ) and a disturbance torque estimation means (e.g., 215) for estimating a disturbance torque for the actuator device using a Kalman filter; a reaction force estimation means (e.g., 216) for estimating a reaction force acting on the actuator device based on the disturbance torque estimated by the disturbance torque estimation means and a model of a state in which the motor torque, static friction, and reaction force are in balance; A control device comprising: According to this configuration, it is possible to realize more accurate control of the actuator device.

[0075] (2) The control device according to (1), wherein the model includes a parameter corresponding to an inertial force. According to this configuration, it is possible to estimate the reaction force with higher accuracy by taking into account the inertial force of the rotating system.

[0076] (3) The control device according to (2), wherein the reaction force estimation means derives an estimated value of the reaction force based on the following equation corresponding to the model:

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[0079] (4) The control device according to any one of (1) to (3), wherein the Kalman filter is a linear Kalman filter. According to this configuration, it is possible to derive an estimated value of the disturbance torque using a linear Kalman filter.

[0080] (5) The control device according to any one of (1) to (3), wherein the Kalman filter is a nonlinear Kalman filter. According to this configuration, it is possible to derive an estimated value of the disturbance torque using a nonlinear Kalman filter.

[0081] (6) The control device according to any one of (1) to (5), wherein the intermediate parameter of the disturbance observer is a value obtained by applying a low-pass filter to a composite value of a torque value derived from a current command value for the motor and a torque value derived from a motor angular velocity. According to this configuration, it is possible to realize more accurate control of the actuator device by using intermediate parameters in the disturbance observer.

[0082] (7) The control device according to any one of (1) to (6), wherein the disturbance torque estimation means further estimates the disturbance torque based on a torque ripple in the motor. According to this configuration, it is possible to estimate the disturbance torque with higher accuracy by taking into account the torque ripple of the motor.

[0083] (8) A method for controlling an actuator device that operates using a motor (e.g., 104), comprising: The intermediate parameters of the disturbance observer (e.g., x Q a disturbance torque estimation step of estimating a disturbance torque to the actuator device using a Kalman filter (e.g., 215); a reaction force estimation step of estimating a reaction force acting on the actuator device based on the disturbance torque estimated in the disturbance torque estimation step and a model of a state in which a motor torque, static friction, and a reaction force are in balance; The control method includes: According to this configuration, it is possible to realize more accurate control of the actuator device. [Explanation of symbols]

[0084] 100...Linear actuator device 101…Controller 102...Motor driver 103…Encoder 104...Motor 105...Motor bearing 106...Coupling 107...Ball screw shaft 108, 109...Ball screw bearings 110…Nut 111...Linear guide 112…Stage 113...Advanced parts

Claims

1. A control device for an actuator device that operates using a motor, comprising: A disturbance observer; a disturbance torque estimating means for estimating a disturbance torque applied to the actuator device by using an intermediate parameter of the disturbance observer and a Kalman filter; a reaction force estimation means for estimating a reaction force acting on the actuator device based on the disturbance torque estimated by the disturbance torque estimation means and a model of a state in which a motor torque, static friction, and a reaction force are in balance; A control device comprising:

2. The control system of claim 1 , wherein the model includes a parameter corresponding to an inertial force.

3. The control device according to claim 2 , wherein the reaction force estimating means derives the estimated value of the reaction force based on the following equation corresponding to the model: [0010]

4. The control device of claim 1 , wherein the Kalman filter is a linear Kalman filter.

5. The control device of claim 1 , wherein the Kalman filter is a non-linear Kalman filter.

6. 2. The control device according to claim 1, wherein the intermediate parameter of the disturbance observer is a value obtained by applying a low-pass filter to a composite value of a torque value derived from a current command value for the motor and a torque value derived from a motor angular velocity.

7. 2. The control device according to claim 1, wherein the disturbance torque estimating means further estimates the disturbance torque based on a torque ripple in the motor.

8. A method for controlling an actuator device that operates using a motor, comprising the steps of: a disturbance torque estimating step of estimating a disturbance torque for the actuator device using intermediate parameters of a disturbance observer and a Kalman filter; a reaction force estimation step of estimating a reaction force acting on the actuator device based on the disturbance torque estimated in the disturbance torque estimation step and a model of a state in which a motor torque, static friction, and a reaction force are in balance; The control method includes:

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