JPH03239171A - Speed control system for ultrasonic motor - Google Patents

Abstract

PURPOSE:To control a change in speed of an ultrasonic motor continuously by providing the speed control system with a phase amplitude change circuit which operates by the signal sent from elastic and viscocity coefficient control circuits and which sends a signal to the ultrasonic motor, controlling the speed of it. CONSTITUTION:A physical detector 2 detects the physical quality of an ultrasonic motor 1. A viscocity coefficient set and control circuit 4, which operates after receipt of signals from a target velocity angular velocity input terminal (a) and the physical detector 2, sends an output signal to a selector 5. An elastic coefficient set and control circuit 7, which operates after receipt of signals from a target position angle input terminal (b) and the physical detector 2, sends an output signal to the selector 5. A phase amplitude change circuit 8, which operates after receipt of output signals from the viscocity and elastic coefficient set and control circuits 4 and 7, controls the speed of the ultrasonic motor 1. A basic phase amplitude generation circuit 9 controls the phase amplitude change circuit 8 and the ultrasonic motor 1.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention includes a viscosity coefficient setting control circuit operated by signals from a target velocity and angular velocity input terminal and signals from a physical quantity detector, and The ultrasonic wave is equipped with an elastic coefficient setting control circuit that is activated by the signal from the position and angular velocity input terminal and the signal from the physical quantity detector, and the speed is controlled by the signal from the phase amplitude change circuit that is activated by the signals from both circuits. Connect to the motor speed control device.

The present invention utilizes the characteristics of an ultrasonic motor, that is, internally synthesizes two single-phase input signals with a phase difference of 90' to create elliptical vibration, and generates driving force by this elliptical motion. The present invention provides a speed control device for an ultrasonic motor that controls the speed by imparting viscous and elastic characteristics to the output shaft of the ultrasonic motor by controlling the phase difference or amplitude of two single-phase human power signals.

[Prior Art] Conventionally, there has been no technology of this type for controlling the speed of an ultrasonic motor by imparting viscous and elastic properties to the output shaft of the ultrasonic motor. In the conventional technology, a general-purpose clutch mechanism or a freewheel hub is connected to the output shaft of a rotating body such as a motor. And the speed vII of the load transfer device or load! In the It II position, the load transmission is discontinuous and the function is only uniform.

Therefore, for example, in the case of a load device in a robot actuator, the function is to grasp and move a predetermined part or object with a predetermined pressure. It was a structure that could not change.

[Problems to be Solved by the Invention] Since the conventional technology has the structure described above, it has the following problems. That is, since the configuration is such that the torque of a rotating body such as a motor is simply transmitted to a friction element or a clutch function, the load transmission function and speed control function are discontinuous and are designed to simply transmit torque. Therefore, it cannot be applied to viscous or elastic loads, and cannot be applied to, for example, a muscular strength training device for patients or rehabilitation for patients. Furthermore, in the field of robots, it is necessary to change the gripping force depending on the parts or objects to be gripped by the actuator, but there have been various disadvantages and inconveniences, such as the inability to deal with this.

The present invention includes a viscosity coefficient setting control circuit that is equipped with a physical quantity detector on the output shaft of an ultrasonic motor, and is operated by speed and angular velocity signals from the physical quantity detector and signals from a target speed and angular velocity input terminal. , an elastic coefficient control circuit operated by position and angle signals from the physical quantity detector and signals from the target position and angular velocity input terminals, and a phase amplitude change circuit connected to the output sides of both circuits. The present invention provides a device that performs continuous speed change control of a sonic motor. Further, the present invention provides a technical means characterized in that it is equipped with a reference phase amplitude generation circuit that is operated by a feedback signal from an ultrasonic motor and outputs an output to the phase amplitude change circuit, thereby solving the problems existing in the conventional technology. This is what I am trying to do.

[Means for Solving the Problems] The present invention employs the following configuration means in order to solve the problems existing in the conventional technology. That is, an ultrasonic motor, a physical quantity detector connected to the ultrasonic motor, and a viscosity coefficient setting control operated by speed and angular velocity signals from the physical quantity detector and signals from a target speed and angular velocity input terminal. circuit, an elastic coefficient control circuit operated by position and angle signals from the physical quantity detector and signals from the target position and angular velocity input terminals, and operated by signals from the elasticity and viscosity coefficient control circuit, A speed control function of an ultrasonic motor is provided, which includes a phase amplitude change circuit that outputs a signal to the ultrasonic motor and performs speed control.

Further, in the speed control device for the ultrasonic motor described above,
There is provided a speed control device for an ultrasonic motor, characterized in that it is equipped with a reference phase amplitude generation circuit that is operated by a feedback signal from the ultrasonic motor and outputs an output to the phase amplitude change circuit.

[Function] Since the present invention is equipped with the configuration means described above, various physical quantities such as shaft torque, shaft angular velocity, and shaft angle from the output shaft of the ultrasonic motor are output to the detector. The output signals from this physical quantity detector are output as position and angle signals to the elastic coefficient control circuit via a selector together with the signal from the target position angular velocity input terminal, and on the other hand, the output signals from the physical quantity detector are The signals from the target velocity and angular velocity input terminals are output as velocity and angular velocity signals to the viscosity coefficient control circuit via the selector, and the output signals from both control circuits are supplied via the selector to the phase amplitude change circuit, and the phase amplitude change By applying the output signal of the circuit to the ultrasonic motor, the speed of the ultrasonic motor can be controlled continuously and smoothly.

Further, a feedback signal is introduced from the ultrasonic motor to operate the reference phase amplitude generation circuit, and its output signal is output to the phase amplitude change circuit, and the phase #ti111! Control the change circuit. On the other hand, the output signal from the reference phase amplitude generation circuit is output to the ultrasonic motor, and the operation of the ultrasonic motor is controlled.

And M! according to the present invention! A speed control device for a sonic motor controls the phase difference or amplitude of two single-phase input signals to give the output shaft of an ultrasonic motor viscous and elastic properties, allowing it to operate continuously and smoothly, unlike conventional devices. It is possible to perform speed control of an ultrasonic motor.

[Embodiment] FIG. 1 is a circuit diagram showing a preferred embodiment of a speed control device for an ultrasonic motor according to the present invention. This will be explained below.

1 is an ultrasonic motor. A physical quantity detector 2 detects physical quantities such as shaft torque, shaft angular velocity, shaft speed, and shaft angle transmitted from the output shaft 1a of the ultrasonic motor 1. The physical quantity detector 2 is, for example, a potentiometer, an encoder, a tacho generator, or the like. a is a target velocity and angular velocity input terminal, which derives a viscosity signal related to velocity and angular velocity to the selector 3; Further, the target velocity and angular velocity input terminal a is connected to, for example, a potentiometer or a tacho generator, and a predetermined viscosity signal is input from the outside, and velocity and angular velocity signals are introduced from the various quantity calculator 2. 4 is a viscosity coefficient setting control circuit, which is connected to the output side of the selector 3. It operates by receiving signals from the target velocity and angular velocity input terminal a and the physical quantity detector 2, and sends an output signal to the selector 5. Reference numeral b designates a target position and angle input terminal, into which elastic signals relating to position and angle are input to the selector 6. Position and angle signals from the physical quantity detector 2 are introduced into the selector 6. 7 is an elastic coefficient setting control circuit, which is connected to the output side of the selector 6. It operates by receiving signals from the target position angle input terminal and the physical quantity detector 2, and sends an output signal to the selector 5.

8 is a phase amplitude changing circuit connected to the output example of the selector 5, which is activated by the output signal of the viscosity and elastic coefficient setting control circuit 4.7, outputs it to the input side of the ultrasonic motor 1, and On the other hand, numeral 9 is a reference phase amplitude generating circuit, which controls the phase amplitude changing circuit 8 with an output signal. Also, one output signal is from the ultrasonic motor! and controls the ultrasonic motor 1. Further, the reference phase amplitude generating circuit 9 receives a feedback signal from the ultrasonic motor 1 and is driven.

In this way, the ultrasonic motor 1 is continuously varied according to the output signals from the phase amplitude changing circuit 8 and the reference phase amplitude generating circuit '#i9. Then, the varied physical quantities such as shaft torque, shaft angle, shaft speed, and shaft angular speed are transmitted to the output shaft 1a. Therefore, if a lever is fixed to the output shaft 1a, a physical quantity is transmitted to the lever, and the muscle strength of a person, such as a patient in a hospital, can be automatically trained by the lever.

Next, the operating principle of the ultrasonic motor speed control device according to the present invention will be explained based on FIGS. 2 and 3.

The driving force τ (kg-e+m) of the ultrasonic motor 1 is determined by the amplitude degree α (%) and the phase difference θ (°) of the two-phase input signal.

In Figure 2, the driving force τ (kg
-cm). If the phase difference θ (°) of the two-phase input signal is Oo, the driving force τ (kg-cm) is 0.
(kg-cm), and if the angle is 90°, the rated drive cuff g
Obtain (kg-e+m).If -90('), the 0 phase difference θ(
If the driving force r (kg −
cva) also changes from the rated value τ@(kg-em) to the opposite rated value τs' (kg·cm) in the same way as the phase difference θ(°) as shown.

Figure 3 shows the driving force τ (kg・1) depending on the liveliness level α (%).
This shows the change in If the amplitude degree α of one of the two-phase human power signals is set to 0 (%), the driving force τ is 0 (kg
-cva ), and the rated value α is 100 (%)
If , the rated driving force τ@(kg-e+i) is obtained. Further, the rotation direction of the ultrasonic motor 1 can be changed by reversing the positive and negative phase difference θ (°).

As shown in FIG. 1, the present invention detects the output part position or the output shaft 1a angle of the ultrasonic motor 1, and calculates the phase difference θ of the two-phase human power signal in proportion to the position, angle, and elastic coefficient to be set.
(°) or the amplitude degree α (%), the ultrasonic motor l generates a driving force τ (kg-cm) proportional to the deviation from the target position or target angle. At this time, the target position,
When the driving force τ (kg-cm) is generated in the direction of pulling back to the target angle, it exhibits elastic characteristics like a spring, and when the driving force τ (kg-cm) is generated in the direction away from the target angle, it exhibits a negative elastic coefficient. It operates as a so-called virtual spring with .

On the other hand, the speed of the ultrasonic motor 1 or the angular velocity of the output shaft la is detected, and the phase difference θ (°) or amplitude degree α (%) of the two-phase human power signal is determined in proportion to the speed, angular velocity, and viscosity coefficient to be set. When controlled, the ultrasonic motor 1 generates a driving force τ (kg·eII) proportional to the speed and angular velocity. At this time, the driving force τ (kg-
cml), it exhibits a characteristic having a positive viscosity coefficient, and when a driving force is generated in a direction that promotes the action of the output shaft 1a, it exhibits a so-called virtual viscosity characteristic, having a negative viscosity coefficient.

Next, the structure of the ultrasonic motor 1 according to the present invention will be explained based on FIG.

lb is a bracket that accommodates each component of the ultrasonic motor l, and Ic is a stator, which is formed into a substantially disk shape.

The stator lc is made up of an elastic ring 1d and a piezoelectric element 1e. The elastic ring 1d is made of, for example, a copper alloy, and the piezoelectric element 1e having a piezo effect is fixed to its lower surface. If is a rotor and is formed into a substantially disk shape. The rotor f consists of a ring 1g and a slider 1h. The ring Ig is made of, for example, an aluminum alloy, and has a structure in which the slider Ih is bonded to the lower surface of the ring Ig. The slider th is provided to obtain a stable coefficient of friction and to drive with high efficiency when the stator IC and rotor 1f are brought into pressure contact, and is made of a material such as engineering plastic, for example.

In the figure, reference numeral 11 denotes a spring, which is arranged on the upper surface of the rotor.

[Effects of the Invention] The speed control device for an ultrasonic motor according to the present invention has the above-described configuration and operation, and therefore has the following effects.

That is, the present invention provides viscous and elastic properties to the output shaft of an ultrasonic motor by controlling the phase difference or amplitude of two single-phase human power signals, thereby producing continuous and smooth ultrasonic waves that are not available in conventional devices. The speed of the sonic motor can be controlled.

Furthermore, if a lever is attached to the output shaft of the ultrasonic motor, the torque from the ultrasonic motor can be variably transmitted to the lever according to viscosity and elasticity signals. Therefore, if the above-mentioned lever is used as a grasping lever for a human muscle strength training device used in medical treatment, it will contribute to strengthening muscle strength.

In addition, if this lever is applied to a robot actuator, it will be possible to apply positive and negative driving forces, and the installed load can be continuously varied based on viscous and elastic signals, allowing fine control of the actuator. , it is possible to provide a device with significantly superior performance compared to existing devices.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing a preferred embodiment of an ultrasonic motor speed control device according to the present invention. Fig. 2 is a characteristic diagram of the driving force τ (kg-(2)) with respect to the phase difference θ (°) in the ultrasonic motor according to the present invention, and Fig. 3 is the amplitude in the ultrasonic motor according to the present invention. Driving force τ for degree d (%)
(kg-cm). FIG. 4 is a partially cutaway perspective view showing the internal structure of the ultrasonic motor. In the figure, l: ultrasonic motor, Ia: output shaft, 2.
...Physical quantity detector, 3.5.6...Selector, 4.
...Viscosity coefficient setting control circuit, 7...Elastic coefficient setting control circuit, 8...Phase amplitude change circuit, 9...Reference phase amplitude generation circuit, a...Target velocity angular velocity input terminal, b...
・Target position angle input terminal and above Patent sponsor: Dai-Seiken Co., Ltd.

Claims (2)

[Claims] (1) An ultrasonic motor, a physical quantity detector connected to the ultrasonic motor, and a viscosity coefficient that operates based on the speed and angular velocity signals from the physical quantity detector, and signals from the target velocity and angular velocity input terminals. a setting control circuit; an elastic coefficient control circuit which operates according to the position and angle signals from the physical quantity detector and signals from the target position angular velocity input terminal; and an elastic coefficient control circuit which operates according to the signals from the elasticity and viscosity coefficient control circuit; A speed control device for an ultrasonic motor, comprising: a phase/amplitude changing circuit that outputs a signal to the ultrasonic motor and performs speed control. (2) The speed control device for an ultrasonic motor according to claim (1), further comprising a reference phase amplitude generation circuit that operates based on a feedback signal from the ultrasonic motor and outputs an output to the phase amplitude change circuit. Ultrasonic motor speed control device.