JPS60255094A - Operation controlling method of stepping motor - Google Patents

Abstract

PURPOSE:To operate in an operation continued to the previous operation by storing a current supply pattern at stopping time and starting supplying of a current on the basis of the pattern. CONSTITUTION:When a control valve 4 is disposed at the position for satisfying a control target value, the output of an input pulse is topped to stop a stepping motor 5, and a control valve 4 is held at the prescribed open position. When the rotating speed of an engine varies, the input pulse is again fed to restart the motor 5. The current supplying pattern at stopping time is stored, a current supply is started on the basis of the pattern to restart the motor. Accordingly, the operation is performed continued to the previous operation, and an inconvenience of rotating more than required does not occur at starting time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for controlling the operation of a step motor used as a servo motor for driving a control member.

As is well known, a step motor consists of a stator with multiple sets of windings and a rotor with permanent magnets or magnetic material, and the rotor is stepped by applying current to the windings in accordance with the input pulse step waveform. It rotates in a shape.

Two examples are the throttle valve that controls the amount of intake air flowing through the engine's intake passage, the opening of the air control valve installed in the bypass, and the intake Control is performed using a step motor that is driven by input pulses generated by an electronic control unit that controls the opening of a flow rate control valve or fuel injection valve that controls the flow rate of fuel sent into the road. Since the step motor can control the opening almost steplessly, the rotational speed and air-fuel ratio of an automobile engine can be changed steplessly, and therefore the air and fuel can be changed steplessly. Suitable for servo motors that require

Among such step motors, the common permanent magnet type normally has four-phase windings, and the rotor is rotated by sequentially switching and supplying current to the two phases. .

Even when the step motor is stopped, current is supplied to two specific phases due to the circuit configuration, and the step motor is restarted by restarting the switching.

As mentioned above, current is supplied to two specific phases of the step motor even when it is stopped, so heat generation increases winding resistance, lowers the current, and lowers the magnetic force.
When the thrust is reduced and stopped for a long time, the control member cannot be driven accurately.

The present invention provides an operation control method that does not cause a drop in current or magnetic force due to heat generation when a step motor stops and restarts, and therefore can always accurately drive a control member with a light-minute thrust.

That is, in order to solve the above-mentioned problems, the present invention stores a current supply pattern when the control member driven by the step motor satisfies the control target value, and stops supplying current to the step motor, thereby achieving the control target value. When the value fluctuates, supply of current is started based on the current supply pattern, and operation of the step motor is restarted.

Embodiment FIG. 1 shows an air passage 3 for idle correction of the engine by bypassing a throttle valve 2 for controlling the amount of intake air provided in the intake passage l of an automobile engine, and the effective area of this air passage 3 is reduced. The idling speed of the engine is maintained at a predetermined value by varying it from zero to the maximum by a needle-shaped control valve 4 driven by a step motor 5.

The step motor 5 includes a stator 6 having windings and a rotor 7 having permanent magnets.The two rotors 7 are mounted on a non-magnetic core material 9 rotatably supported by a casing 8, and the rotor 7 is mounted at the center of the core material 9. The threaded portion of the output shaft lO is screwed into the threaded hole. The control valve 4 is provided at the tip of the output shaft lO and reciprocates in a straight line by a distance determined by the number of input pulses supplied per turn lsK, the number of poles of the rotor 7, and the pitch of the threaded portion. That's what I do.

Also, a rotation sensor 2 for battery power supply voltage ll and engine rotation speed. Engine temperature sensor 13. Throttle valve 2 opening sensor 4L suction pipe pressure sensor 5. Engine exhaust gas oxygen sensor 16 Other heart IPK Yoji engine Q
Electrical signals output from sensors provided to detect operating conditions and the environment are sent to an electronic control unit (17).

Voltage level adjuster and waveform shaper not shown.

The input port 18) C is input via a converter etc. The electronic control unit 17 is connected to a central processing unit (CP) other than the above.
U) 19. Timer 20. Read-on memory (ROM)
21. Random access memory (RAM) 22. Output boat 23. It includes a drive circuit 24 for the step motor 5.

The electrical signals sent from the sensors are data-processed, and when it is determined that the engine is in an idling state based on the electrical signal from the opening sensor 14, the engine speed is corrected to a predetermined engine speed according to the operating state and environment of the engine. The input pulse with the added value is sent from the drive circuit 24 to the step motor 5,
The control valve 4 is driven to a predetermined opening position. When a predetermined engine speed is obtained and the control valve 4 is placed at a position that satisfies the control target value, the output of the input pulse is stopped, the step motor 5 is stopped, and the control valve 4 is moved to the predetermined opening position. to hold. When the engine speed changes, the input pulse is sent again to restart the step motor 5.

FIG. 2 is a flowchart showing an example of a method for controlling the operation of the step motor 5. First, in step 31, it is determined whether the control objective, for example, the engine rotational speed, is a control target value.

If it matches the control target value, it is determined in step 32 whether or not the current supply was stopped last time, and if it was not stopped, the current current supply pattern is stored in step 33.

In step 34, the supply of current is stopped and the step motor 5 is stopped. If it does not match the control target value, it is determined in step 35 whether or not the current supply was stopped last time, and if it has been stopped, step 36#I
The current supply pattern before the stop stored in C is called up, the current, that is, the input pulse is outputted in step 31, and the next current supply pattern is determined based on the currently outputted current supply pattern in step 38. is determined, and a current is supplied to the step motor 5 in step 39.

If it is determined in step 35 that the current supply was not stopped last time, the arithmetic processing in steps 38 and 39 is performed.

Although the step motor 5 in FIG. 1 linearly reciprocates the output shaft 10, it goes without saying that the present invention can also be applied to a motor that rotates the output shaft 10 to rotationally drive a control member.

Effects of the Invention According to the present invention, when the control member driven by the step motor satisfies the control target value, the current supply is stopped and the step motor is stopped, so even if the control member is stopped for a long time, the thrust force does not decrease due to heat generation. There is no invitation. and.

Memorize the current supply pattern when stopping.

Based on this pattern, the current supply is started and the step motor is restarted, so the operation continues from the previous operation, and if the step motor is rotated more than necessary at startup, there will be no problem. .

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the present invention. FIG. 2 is a flowchart showing an example of an operation control method. 4...Control valve, 5...Step motor, 6...Stator, 7...Rotor, 10
...Output shaft. 17...Electronic control unit. 1st City Figure 2

Claims (1)

[Claims] When the control member driven by the step motor satisfies the control target value, the current supply pattern is memorized and the supply of current to the step motor is stopped, and when the control target value fluctuates, the current supply pattern is changed based on the current supply pattern. A step motor operation control method characterized by starting supply and restarting operation of the step motor.