KR20060094744A - Motor driving method and circuit for minimizing resistance of counter electromotive force - Google Patents

Abstract

The present invention relates to a motor driving method and circuit, and more particularly to a motor driving method and circuit for minimizing the resistance force by the back electromotive force of the motor drive device. The present invention is applied to a motor driving circuit for a force reflecting haptic device to prevent performance degradation due to back EMF generated in the driving motor when the haptic device is used. To date, haptic devices are mostly driven by electric motors, and are generally used by mounting a motor driving circuit of PWM (Pulse Width Modulation) method. The PWM signal is amplified by the input power through an H-shaped H-bridge circuit to drive the motor. The present invention is to switch the switch of the H-bridge circuit by receiving the PWM signal and the direction (DIR) signal so that the output is low when the PWM signal is low, the resistance force by the back electromotive force of the electric motor generated when using the haptic device Minimize. Accordingly, the motor driving circuit of the present invention includes a PWM signal processor for driving the motor of the haptic device; And an H-bridge circuit for driving the motor. The motor driving circuit for the haptic device according to the present invention can be widely applied to a user interface requiring force reflection, and in particular, it can be used in fields such as driving / manipulation of mechanical systems such as robots and adjustment mechanisms such as low-cost game machines. .

Description

Motor driving method and circuit for minimizing resistance by counter electromotive force {Motor driving method and circuit for minimizing resistance of counter electromotive force}

1 is a circuit diagram schematically illustrating a conventional motor driving circuit.

FIG. 2 is a motor drive control logic table based on the PWM method of FIG. 1.

3 is an equivalent circuit diagram of the motor driving circuit at the moment when the motor output is zero.

4 is a circuit diagram for schematically illustrating a motor driving circuit according to the present invention.

FIG. 5 is a motor drive control logic table based on the PWM method of FIG. 4.

<Explanation of symbols for the main parts of the drawings>

10 ... PWM signal 15 ... Direction signal

20 ... control logic circuit 30 ... H-bridge circuit

320-380, switch 400 ... motor

500 ... power

The present invention relates to a motor driving method and circuit, and more particularly to a motor driving method and circuit for minimizing the resistance force by the back electromotive force of the motor drive device. In particular, the present invention is applied to a motor driving circuit for a force reflecting haptic device, and relates to a motor driving method and circuit for preventing the performance degradation due to back EMF generated in the drive motor when using the haptic device.

The haptic device receives a position input from an operator and is a bidirectional input / output device designed to allow the operator to feel power. In general, the haptic device is composed of a mechanical unit driven by a motor, a user connecting device such as a handle, a sensor unit for recognizing a position of the user connecting device, and a controller for controlling and signal processing thereof.

Representative performance items of haptic devices, such as the size of the position recognizable area regarding how much the operator's position input can be detected, the accuracy of position recognition on how accurately the operator's position input can be detected, Maximum output on how much force can be reflected to the operator, and maximum resistance on the magnitude of the resistance generated by the haptic device itself according to the operator's movement.

The motor driving method and circuit of the present invention relates to a technique for reducing the maximum resistance among the performance items of the haptic device. As described above, the haptic device is designed to give the operator a feeling of virtual force and give a sense of reality. When the device itself has resistance, the user can easily feel fatigue, and moreover, the resistance to reflect the force It can be distorted. In addition, expensive sensors and related devices are required to correct this.

The resistivity of the haptic device also occurs in the mechanical resistance of the mechanism, but also through the back electromotive force of the electric motor. Especially, the PWM and H-bridge circuits, which are the most representative motor driving circuits, have a problem with the performance of the haptic device due to this problem. It is a reality that adversely affects. In order to overcome this problem, many haptic devices employ a current amplifying circuit in the motor driving circuit, but this has the disadvantage of causing the complexity of expensive sensors and related circuits.

The technical problem to be achieved in the present invention, by providing a motor driving method and circuit for minimizing the resistance by the back electromotive force for the motor drive of a motor driving device such as a haptic device, by minimizing the drive resistance by the back electromotive force without a separate sensor An object of the present invention is to implement a haptic device having a high quality force reflection performance.

According to an aspect of the present invention, there is provided a motor driving method including an H-bridge circuit for driving a motor by receiving an input signal of a pulse width modulation (PWM) method. Receiving a direction signal for determining a driving direction of the motor and outputting a motor driving signal; And outputting all of the driving signals output to the H-bridge circuit to the low level when the PWM signal is low, thereby minimizing the resistance caused by the back electromotive force of the motor.

The present invention provides a motor driving circuit for driving a motor having an H-bridge circuit for driving a motor by receiving an input signal of a pulse width modulation (PWM) method in order to achieve the above technical problem, the PWM signal and the motor And a control logic unit for receiving a direction signal for determining a driving direction of the motor and outputting a motor driving signal. When the PWM signal is low, all of the driving signals output to the H-bridge circuit are outputted low, thereby preventing the counter electromotive force of the motor. It provides a motor drive circuit to minimize the resistance by the.

Hereinafter, with reference to the accompanying drawings, it will be described the configuration and operation of the motor driving method and circuit for minimizing the resistance force by the back electromotive force according to the present invention.

Before describing the features and operations of the present invention according to an embodiment of the present invention, the characteristics of the existing circuit will be described first.

Representative PWM motor driving circuit is shown in FIG. The control logic of the existing circuit outputs a drive signal from the control logic unit 2 according to the PWM input signal 1 of the host controller, and these drive signals are output from the four drive switches 32, H, on the H-bridge circuit 3. 34, 36, and 38 (S1, S2, S3, S4) are on-off controlled, and FIG. 2 is a drive switch driving logic table. At this time, the magnitude of the equivalent voltage (Vm) applied to the motor 40 is

Vm = (2.0) x (Vss) x (PWM Duty Cycle-0.5)

Where Vss represents the power supply voltage 5 and PWM duty cycle (duty ratio) represents the ratio of time that On is maintained per pulse period of the PWM signal.

The duty ratio at the moment the motor output is zero is 0.5. In this case, it can be seen that an equivalent circuit as shown in FIG. If the motor is operated by an external force in the state in which both ends 42 and 4 of the motor 40 are connected, the motor 40 operates as a generator to generate a resistance against the operation of the motor by counter electromotive force. When the PWM driving circuit of FIG. 1 is applied to a haptic device motor due to such a circuit problem, even if a PWM signal is generated such that the output of the motor is zero in the host controller, the operator feels resistance and degrades the performance of the haptic device. Let's do it.

In order to solve this disadvantage, the present invention provides a motor driving method including an H-bridge circuit for driving a motor by receiving an input signal of a pulse width modulation (PWM) method, wherein the PWM signal and the motor are driven. Receiving a direction signal to determine a direction and outputting a motor driving signal; And outputting all of the driving signals output to the H-bridge circuit to the low level when the PWM signal is low, thereby minimizing the resistance caused by the back electromotive force of the motor.

The motor driving method of the present invention can be applied to any system using a motor, but here, it will be described in detail that it is applied to a motor driving circuit of a haptic device used to give an operator a virtual feeling of reality. do.

<Example>

4 is a block diagram of a motor driving circuit for a haptic device according to an embodiment of the present invention. In the present invention, in order to solve the resistance problem by the counter electromotive force mentioned above, the driving circuit as shown in Figure 4 was devised, and by implementing the control logic for the haptic device as shown in Figure 5 it was possible to minimize the counter electromotive force. Since detailed circuits for the control logic as shown in FIG. 5 exist in various forms, a description thereof will be omitted.

The PWM motor drive circuit of the present invention is as shown in FIG. The control logic of the control logic unit 20 is the input of the control logic for the haptic device implemented is a PWM signal 10 and a direction (DIR) signal 15 for determining the driving direction of the motor, the control logic unit 20 The driving signals are output by logically combining the input signals, and the driving signals are turned on by four drive switches 320, 340, 360, and 380 (S1, S2, S3, and S4) on the H-bridge circuit 30. Off control, Figure 2 is a drive switch drive logic table. .

 At this time, the magnitude of the voltage applied to the motor 400

Vm = (Vss) x (PWM Duty Cycle)

The polarity of the voltage is positive when the DIR signal is high and negative when low.

In the motor driving circuit configured as above, voltage is applied to the motor when the PWM signal is high. When the PWM signal is low, all the drive switches 320, 340, 360, and 380 (S1, S2, S3, S4) are turned off. (Off), unlike the conventional case in which the positive pole of the motor is connected, the circuit is separated. In this case, no counter electromotive force is generated.

When the motor driving circuit implemented as described above is applied to the haptic device, the resistance of the haptic device due to counter electromotive force can be minimized.

As described above, the present invention provides a motor driving method and a circuit for minimizing the resistance by the back EMF for driving the motor of a motor driving device, such as a haptic device, by minimizing the driving resistance by the back EMF without a separate sensor of high quality Haptic devices with force reflection capabilities can be implemented.

Claims (2)

In a motor driving method for driving a motor having an H-bridge circuit for driving a motor by receiving an input signal of the pulse width modulation (PWM) method, Receiving a PWM signal and a direction signal for determining a driving direction of the motor and outputting a motor driving signal; And And outputting all of the driving signals output to the H-bridge circuit to the low level when the PWM signal is low, thereby minimizing the resistance caused by the counter electromotive force of the motor. In a motor driving circuit for driving a motor having an H-bridge circuit for receiving a pulse width modulation (PWM) input signal to drive the motor, And a control logic unit configured to receive the PWM signal and the direction signal for determining the driving direction of the motor, and output a motor driving signal. When the PWM signal is low, all the driving signals output to the H-bridge circuit are outputted low. The motor drive circuit thereby minimizing the resistance caused by the back electromotive force of the motor.

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