JPS60183998A - Controller of step motor - Google Patents

Abstract

PURPOSE:To effectively stop at a target position by intermittently exciting an exciting coil of non-excited state at the stopping time only during the prescribed period. CONSTITUTION:When the counted result of a counter COUN arrives at a target position, a comparator COM produces an output to drive a shortcircuiting pulse generator SPG of a control circuit. When the generator SPG is driven, switches SW1-SW4 of the control circuit connected in parallel with a plurality of circuit exciting coils CL1-CL4 are shortcircuited during the prescribed period (t). An exciting pulse is applied from the generator SPG to a transistor corresponding to the exciting coil to be in the nonexcited state during the prescribed period (t) that the switches SW1-SW4 are shortcircuited.

Description

[Detailed description of the invention] The present invention relates to a step motor control device.

Conventionally, a step motor is equipped with multiple excitation coils, and the excitation/9 phase is sequentially shifted by a control circuit.
When a pulse was applied ((therefore, it was driven).

However, the step motor has inertia and cannot be suitably stopped at a target position, for example, a position rotated by N steps.

Therefore, in order to stop the coil at the target position suitably and in a short time, control is performed to excite the excitation coil that is in a non-excited state when the target position is reached, in other words, when the number of excitation pulses corresponding to the target position is applied. device was proposed. Although this control device has the advantage that the means for stopping the step motor can be extremely simplified, there is a risk that the restraint force on the rotor is only the detent torque, which may cause a tax adjustment depending on the position or speed of the rotor just before the target position. Furthermore, since there is generally at least a 4-inch difference in holding torque, there is also the problem that it is not possible to properly stop the vehicle at the target position.

The present invention proposes a step motor control device that eliminates the above-mentioned drawbacks.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A step motor control device according to the present invention will be explained below with reference to the drawings.

In FIG. 1, CLw=CL4 is an excitation coil of a step motor, one end of which is connected to a constant voltage source V, and the other end of which is grounded via a transistor 'l'rl-Tri of a control circuit. G is the transistor whose output terminal is
A date circuit of the control circuit connected to the bases of l''r4-Tr4 applies excitation pulses φX to φ4 to the bases of the transistors TrI to 'f'r4, respectively.

The CPU is a central control circuit of the control circuit that controls the gate circuit G, and controls the control circuit in response to an externally applied control signal, for example, a command signal Sl that causes the step motor to rotate by N steps and move to the 0 position. A signal for controlling the gate circuit G is generated using the stored contents of the storage device ROM.

In the step motor control device of the present invention, a command signal S! from the outside instructs the central control circuit CPU to rotate the step motor N steps. When given, the central control circuit CPU generates a signal to drive the gate circuit G according to a program stored in the storage device ROM. The gate circuit G generates excitation nodes φ1 to φ4 as shown in FIG.
Give it to the base of 'l'r4. Transistors Tr1-T
r4 is sequentially made conductive according to the excitation noggles φ1 to φ, and provides an excitation current to the excitation coils CLI to CL4. In Figure 2, the position one position before the target position, that is, (N-1
) The excitation coils CLI-CL4 are excited by phase-shifted excitation and e Lus until the target position G! ,
That is, the energized coil should be in the de-energized state at the position of N steps, for example, CLI r C'Lrx for /9i period t
In addition, excite multiple times, for example, 5 times during
For example, the excitation coil that should be in the excitation state in the
By keeping CL4 in a normally excited state even after the predetermined period t has elapsed, the step motor can be suitably stopped at the desired target position.6 Figure 3 shows that the rotation step ST of the step motor in Figure 2 is at the target position. That is, it shows the stopping operation of the rotor when the N step is reached. It is clear that the control device of the present invention can suitably stop the motor at the position l':4 shown by the solid line in FIG. In FIG. 3, the stopping operation of the rotor is shown by a broken line for comparison without using the control device of the present invention, that is, when the excitation coil, which should be in a non-excited state, is not energized at all at the target position.

In the control device of the present invention, the length of the pJi period during which the excitation coil, which should be in a non-excited state, is intermittently excited multiple times may be determined by taking into account the shape of the rotor, the shape of the excitation coil, and other factors. That should be obvious.

FIG. 4 shows another embodiment of the step motor control device of the present invention. In FIG. 4, an excitation/Q pulse generation circuit PG of the control circuit generates excitation pulses φ1 to φ4 whose phase is sequentially shifted in response to a control signal S2 applied from an external source, and transistors Tr1 to Tr1 of the control circuit generate excitation pulses φ1 to φ4 whose phase is shifted sequentially. Drives Tr4. As a result, the excitation coils CLs to CL4 are sequentially excited to move the rotor toward a target position, for example, N-step rotational position.

The number of pulses in the control signal S2 is determined by the counter C of the control circuit.
0UN is counted and the counting results are outputted one after another. The count result of the counter C0UN is sent to the comparison circuit COM of the control circuit, where it is determined whether the number of rotation steps N corresponding to the target position has been reached. Counter C0U
When the count result of N reaches N, the comparison circuit COM generates an output and drives the short circuit pulse generation circuit 5PCI of the control circuit.

When the short circuit/Q pulse generation circuit SPG is driven, the excitation coil CL+~
Switches S W+ = S W4 of the control circuit connected in parallel to CL4 are short-circuited. switch SW
! ~SW4 is short-circuited for a predetermined period t.

The transistor corresponding to the excitation coil, which should be in a non-excited state, is also given an excitation 7Q pulse from the excitation pulse generation circuit PG, and is brought into a conductive state. In other words, during the predetermined period t, all the transistors Tr+ to 'l'r4 are in a conductive state, and all the excitation coils CL+ -C are kept in a conductive state.
L4 is in an excited state. As a result, the rotor can be suitably stopped at the target position as in the embodiment shown in FIG. The set value of the comparator circuit COM can be changed as appropriate depending on the contents of the first control signal S2. It will be obvious that the set value may be changed or fixed by other methods.

In the above-mentioned embodiment, the excitation coil, which should be at least in a non-excited state, is intermittently energized only in the step corresponding to the target position, that is, in the final step. It will be clear then that the excitation coil, which should be at least in a de-energized state, may be energized intermittently between at least one step preceding the final step and the final step.

Although transistors are used in the above description, it will be appreciated that other suitable switching elements may be used. It will be obvious that the switch may also be implemented using a transistor or other well-known switching element or structure.

As is clear from the above, in the step motor control device of the present invention, at least the excitation coil that is in a non-excited state among the excitation coils is intermittently excited only for a predetermined period at least in steps corresponding to the target position. When the predetermined period of time has elapsed, the eyes can be reliably stopped at the desired position.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the step motor control device of the present invention. FIGS. 2 and 3 are explanatory diagrams of the same operation, and FIG. 4 shows an embodiment of the same in the package. CL+~CL4...Excitation coil, CPU...Central control circuit, COM...Comparison circuit %C0UN...Counter, G...Gate circuit, PG...Excitation pulse generation circuit, ROM... Storage device, Sl...instruction number 4it, Ss...control signal, SPG...short circuit/Q pulse generation circuit, SWs to SW4=-switch, Trl-T
rl ・) Transistor, 10V...constant voltage source. Agent Masumeshi Imamura Noshi Figure 3

Claims (1)

[Scope of Claims] fil A step motor control device that rotationally moves a shirrotor to a target position # by sequentially exciting an excitation coil with excitation pulses that are sequentially phase-shifted by a control circuit, wherein at least the step motor corresponds to the target position #. An fti control device for a step motor, characterized in that in a step, at least one of the excitation coils that is in a non-excited state is continuously excited for a predetermined period of time. (2) The control circuit includes a transistor that connects the excitation coil to 'tJiW, and the transistor corresponding to at least the excitation coil in a non-excited state among the excitation coils is set at least in the step corresponding to the target position. 2. The step motor control device according to claim 1, wherein the step motor is intermittently conductive only during a period of time. (3) The control circuit includes a switch arranged in parallel with the excitation coil, and the transistor corresponding to the excitation coil which is in a de-energized state at least in the step corresponding to the target position is also made conductive for a predetermined period, and the switch 2. The step motor control device according to claim 2, wherein the step motor is short-circuited in a UTftx manner during the predetermined period.