JPH0611193B2 - Motor position control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor position control method, and more particularly to a motor position control method suitable for smooth and quick positioning control. .

[Background of the Invention]

For the position control of the DC motor, see, for example, the Institute of Electrical Engineers of Japan, Information Processing Research Society material, material number “IP-82-3
4 ”.

The conventional technique will be described below by taking the case where the encoder is used as the rotation detector as an example.

Here, FIG. 3 is a block diagram of a conventional DC motor control system, FIG. 4 is each waveform phase diagram thereof, and FIG. 5 is an explanatory diagram of the relationship between speed, position and time at the time of position control, FIG. 6 is a deceleration speed command pattern diagram.

That is, first, in FIG. 3, the DC motor M is
Transistors Q _A (+), Q _A (-), Q _B (+), Q _B (-) 4
Connected to the center of the full-bridge type, and the base of each of these transistors is connected to each of the resistors _RA (+), R
It is connected to the micro computer MPU via _A (-), R _B (+), and R _B (-).

When the transistors Q _A (+) and Q _A (-) are turned on by the output of the micro computer MPU, the DC motor M is rotated forward, and when the transistors Q _B (+) and Q _B (-) are turned on, the DC motor M is turned on. M is rotated in the opposite direction.

Further, an encoder E relating to a rotation detector is directly connected to the shaft of the DC motor M, and the encoder E outputs the output φ _A shown in each waveform phase diagram of FIG. 4 in accordance with the rotation of the DC motor M. , Φ _B , two-phase rectangular waves with different phases are output.

The outputs Φ _A and Φ _B have the opposite phases of advance and delay depending on the rotation direction of the DC motor M. That is, when the DC motor M rotates in the forward direction, the output φ _A advances, while when the motor M rotates in the reverse direction, the phase of the output φ _B advances.

Then, the up-down counter circuit UDCNT detects the rising and falling edges of the outputs φ _A and φ _B of the encoder E as shown by the pulse FC in FIG. , Up-counting or down-counting the pulse FC that has been quadrupled according to the rotation direction of the DC motor M, and counting the counter value COUNT,
The information is input to the microcomputer MPU as speed or position information.

Further, the up-down counter circuit UDCNT changes the rotation direction signal of the DC motor M, that is, the rotation direction signal ROT in FIG. 4 to H or L by the phase advance or delay of the outputs φ _A and φ _B of the encoder E. , Is input to the micro computer MPU.

The INF is an interface circuit, and the interface circuit INF and the microcomputer MPU are related to the instruction control unit. Note that i
_{R 1} and i _I are the current directions to the right and left of the DC motor M,
V _S is a power supply.

Then, the up-down counter circuit UDCNT micro-computer MPU inputs the signal of the encoder E as a feed back signal, and outputs a drive signal adjusted to obtain a predetermined rotation speed and rotation angle of the DC motor M. Further, each of the four transistors constitutes a drive circuit which receives the drive signal and drives the DC motor M.

With such a configuration, when the speed command SC, the position command PC, and the operation command CTL are input to the micro computer MPU via the interface circuit INF, the micro computer MPU detects the speed, position, and time during position control. As shown in FIG. 5 which is an explanatory view of the relationship of the above, after accelerating up to the commanded speed S, rotating it at the commanded speed, monitoring the counter value COUNT, and starting the position where it can be stopped in the optimum pattern, that is, deceleration When the position X _{1 is} reached, the speed is reduced in accordance with the deceleration speed command pattern P ₁ in FIG. 6, which is a deceleration speed command pattern diagram set in advance in the microcomputer MPU, and the area near the stop position (A area).
, The DC is directly calculated from the remaining pulse number as follows.
And it has calculated Deyutei V _d is a power supply amount to the Motoru M, switched to deceleration based thereon, and performs deceleration.

V _d = k ₁ (θ + S _n ), where k ₁ is a constant, θ is the number of remaining pulses, and S _n is a term of time integration.

In FIG. 6, P ₁ ′ and P ₁ ″ represent other deceleration speed command patterns with different deceleration modes, and X ₁ and
X ₁ ′ and X ₁ ″ indicate respective deceleration start positions.

Although the position control of the DC motor M is performed as described above, the deceleration based on the deceleration speed command pattern is switched to the deceleration based on the direct calculation of the duty in a region, that is, for example, as described above. Once in the area A, regardless of whether there is a difference between the energization amount to the DC motor M according to the deceleration speed command pattern and the same energization amount according to the direct calculation of the duty, the switching is performed. If there is a difference between the motor rotation speed and the latter motor rotation speed, a sudden acceleration or deceleration occurs at that point, and smooth deceleration cannot be obtained.

[Object of the Invention]

An object of the present invention is to provide a motor position control method with smooth deceleration characteristics.

[Outline of Invention]

The motor position control method according to the present invention includes a motor, a rotation detector that outputs a signal corresponding to the rotation of the motor, and a signal of the rotation detector that is input as a feedback signal to obtain a predetermined rotation speed of the motor. And a position control circuit for the motor, which includes a control unit that outputs a drive signal adjusted to obtain the rotation angle and a drive circuit that drives the motor in response to the drive signal, and controls the deceleration gradient when positioning is stopped. It is stored in the control unit as a command pattern, and deceleration is performed when positioning is stopped according to this speed command pattern.In addition, in the extremely low rotation speed range near the stop position, the amount of electricity supplied to the motor is calculated directly from the remaining travel distance. In the motor position control method that calculates and decelerates and stops at the target stop position, the speed command pattern Switching from deceleration according to the current distance to deceleration by direct calculation from the remaining travel distance is performed at the position where the amount of electricity supplied to the motor by both is compared and the amount of electricity supplied by the latter is smaller than the amount of electricity supplied by the former. Even when the amount of electricity supplied by the latter does not become smaller than the amount of electricity supplied by the former, it is carried out as long as it reaches a position extremely close to the stop position.

Switching between deceleration based on the deceleration speed command pattern and deceleration based on direct calculation is not performed uniquely for each region, but the amount of energization is compared by both, and the amount of energization by the latter is
The deceleration is smoothed by performing when the amount of electricity supplied by the former is smaller than that. Also, paying attention to the fact that the rotation speed of the motor is very small in the immediate vicinity of the stop position, and when the above switching does not occur, that is, when the energization amount by the former is smaller than the energization amount by the latter, In the immediate vicinity of the stop position, the former is uniquely switched to the latter so as to quickly stop the positioning.

Example of Invention

An embodiment of the present invention will be described with reference to FIGS.

Here, FIG. 1 is an explanatory view of the relationship between speed and time at the time of position control by the motor position control method according to an embodiment of the present invention, and FIG. 2 is a flow chart showing the position control procedure. Is.

Therefore, the position control circuit of the motor in the embodiment of the present invention is the same as that of the conventional example shown in FIG. In addition, the method of decelerating according to the deceleration speed command pattern and switching to deceleration by direct calculation when it reaches a certain area is the same, but instead of switching uniquely in the area, the energization amount of both is compared and the The switch is made according to the size. The details will be described below.

As described above, FIG. 1 is a diagram showing deceleration near the stop position, A is the same region as A shown in FIG. 5, Q is a motor speed according to a deceleration speed pattern, and R is
Is a motor speed obtained by direct calculation, and B is a newly provided area described later.

When performing position control, as shown in FIG.
After accelerating up to, the deceleration is performed from the position of X ₁ according to the deceleration speed command pattern. This is the motor speed Q in FIG.

When the DC motor M is decelerated like the motor speed Q and reaches the area A, the energization amount to the DC motor M at the motor speed Q is compared with the energization amount to the motor speed R, that is, at C, the motor The speed Q is switched to the motor speed R.

Further, in the area A, when the motor speeds Q and R do not intersect, the area B (area very close to the stop position,
For example, when the rotation angle of the motor shaft reaches an area within 3 degrees), the motor speed Q is switched to the same speed R.

This procedure is shown in the flow chart of FIG.

First, it is determined whether or not it has reached within the area A, and if it has not reached it, it is decelerated according to the deceleration speed command pattern, that is, it decelerates like the motor speed Q in FIG.

If it is reached, the amount of electricity to the motor according to the deceleration speed command pattern is compared with the amount of electricity directly calculated from the number of remaining movement pulses related to the remaining movement distance, and if the latter is smaller than the former, the latter is used. , And subsequent deceleration.

If the former is smaller than the latter, it is determined whether or not the region B has been reached. If not, the former decelerates, and if the latter, the latter decelerates. .

As described above, by switching between deceleration based on the deceleration speed command pattern and deceleration performed by directly calculating the energization amount based on the number of remaining movement pulses described above, there is no sudden acceleration or deceleration during switching, Above all, it is possible to perform position control of deceleration characteristics without hunting.

In the above description, the region B, that is, the region extremely close to the stop position, is illustrated as a region within 3 degrees due to excessive rotation of the motor shaft. However, this rotation angle is not limited to the inertia of the motor itself and the external load. Including inertia,
When the inertia is large, the rotation angle may be 3 degrees or more. On the contrary, when the inertia is small, it is necessary to select an angle range less than 3 degrees. Is something that can be done.

〔The invention's effect〕

According to the present invention, since the position control can be performed near the stop position without causing a rapid speed change, it is possible to perform the position control with a smooth deceleration characteristic.

[Brief description of drawings]

FIG. 1 is an explanatory view of the relationship between speed and time at the time of position control by a motor position control method according to an embodiment of the present invention, and FIG. 2 is a flow chart showing the position control procedure.
FIG. 3 is a block diagram of a conventional DC motor control system, FIG. 4 is a waveform phase diagram thereof, and FIG. 5 is an explanatory diagram of the relationship between speed, position and time during position control, and FIG. FIG. 4 is a deceleration speed command pattern diagram. M: DC motor, E: Encoder, Q _A (+), Q
_A (-), Q _B (+), Q _B (-) ... Transistor, _RA (+),
_{R A (-), R B} (+), R B (-) ...... resistance, UDCNT ...... up-down counter circuit, COUNT ...... counter value, MPU ...
... Microcomputer, INF ... Interface circuit, CTL ... Run command, SC ... Speed command, PC ...
... Position command, ROT ... Rotation direction signal, φ _A , φ _B ...
The output of the encoder, FC ...... 4-doubled pulses of the encoder, a V d _...... energization amount Deyutei, Q, R ......
Motor speed, A, B ... area, S ... speed, P ₁ ...
Deceleration speed command pattern.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junshiro Inamura 1-1-1, Higashitaga-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Taga factory (72) Inventor Kunio Miyashita 4026 Kuji-cho, Hitachi-shi, Ibaraki Hitachi Research Laboratory, Hiritsu Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A motor, a rotation detector that outputs a signal according to the rotation of the motor, and a signal from the rotation detector are input as a feedback signal to obtain a predetermined rotation speed and rotation angle of the motor. The position control circuit of the motor, which consists of the control unit that outputs the drive signal adjusted as described above and the drive circuit that receives the drive signal and drives the motor, uses the deceleration gradient when positioning is stopped as the speed command pattern in the control unit. In the range where the rotation speed is extremely low near the stop position, the amount of electricity to the motor is directly calculated from the remaining travel distance to decelerate in accordance with this speed command pattern. In the position control method of the motor that stops the motor at the target stop position, The switching to deceleration by direct calculation from the travel distance is performed at the position where the amount of electricity to the motor by both is compared and the amount of electricity by the latter is smaller than the amount of electricity by the former. The motor position control method is characterized in that it is carried out when the vehicle reaches a position very close to the stop position even when the electric current amount due to is not smaller than that. 2. The switching of deceleration according to the speed command pattern from deceleration according to the speed command pattern to deceleration by direct calculation based on the remaining travel distance, the energization amount by the latter does not become smaller than the energization amount by the former. In this case, the position control method of the motor is performed when the rotation angle of the motor shaft is within 3 degrees, which is very close to the stop position.