JPH0340194A - Motor controller for automatic vending machine - Google Patents

Abstract

PURPOSE:To make the quantity of rotation of a DC motor approach a targeted quantity more accurately by sufficiently decelerating the rotating speed of the DC motor when setting a second switching element at an on-state and applying regenerative brake. CONSTITUTION:A control part 10 is provided which turns off a first switching element 1 from a time when a first comparison part 9 detects the coincidence of a targeted value with the developmental pulse of a pulse generator 6 and sets the second switching element at the on-state. When the DC motor M is energized until the number of developmental pulses of the pulse generator 6 mounted on the output shaft of the DC motor M arrives at a preset value before stopping, the DC motor M is rotated with inertia after energizing is completed. When the motor M is rotated with the inertia and the number of developmental pulses of the pulse generator 6 arrives at the targeted value, the regenerative brake is applied on the DC motor M, and the rotating speed with inertia of the DC motor M is decreased steeply, then, the rotation of the motor is stopped. In such a way, it is possible to make the quantity of rotation of the DC motor M of a controlled system approach the targeted quantity more accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a DC motor used in a vending machine.

Conventional technology In cup-type vending machines, which use a cooking process in which raw materials are placed in a cup and then boiling water is poured into the cup, a DC motor is used as a power source to cut raw materials from a raw material tank using a screw feeder. ing. In addition, instead of dispensing the cups directly to the product outlet, a robot hand waits at the cup dispensing position of the cup dispenser, and the robot hand receives the dispensed cups and receives the raw materials at the first stage. A DC motor is also used to drive a robot hand in a cup-type vending machine that handles a cup between a second position, a second position where hot water is poured, and a third position facing a product outlet.

FIG. 3 shows a conventional motor control device connected to a DC motor of a robot hand. The power supply circuit of the DC motor M to be controlled includes a first switching element 1 in series.
A second switching element 2 is connected in parallel to the power supply circuit of the DC motor M. A pulse generator 6 composed of a slit plate 4 and a photointerrupter 5 that detects passage through the slit of the slit plate 4 is attached to the output shaft 3 of the DC motor M. Pulse generator 6
A counter 7 counts the pulse signal P generated each time the sensor detects a slit. Target value N set according to the target position of robot hand 8 driven by DC motor M.

and the occasional count value Ns of the counter 7 are the first comparator 9
are compared.

1st. The second switching elements 1 and 2 are connected to the first comparison section 9
The control unit 10 performs the following control according to the comparison result.

At the start of operation, the control unit IO sets the first switching element 2 to the "on" state (see FIG. 4(b)) and the second switching element 2 to the "off" state (see FIG. 4(c')). Reference]. As a result, the power supply circuit of the DC motor M is energized, the DC motor M rotates, and the robot hand 8 starts moving toward the destination. Along with this, the slit plate 4 rotates, and the count value of the carantuff increases monotonically as shown in FIG. 4(a). When the robot hand 8 arrives at the destination, the first comparator 9 determines that "Ns>N.

Detecting this, the control unit IO turns the first switching element 1 "off" and the second switching element 2 "'on" to apply braking and stop the robot hand 8 near the destination. let Figure 4(d) shows the robot hand 8.
It can be seen that the movement speed of the second switching element 2 is slowed down and stopped due to the braking by the ``driver'' of the second switching element 2.

Problems to be Solved by the Invention In such a conventional configuration, the second switching element 2
However, as shown in FIG. 4, (d), override due to inertia occurs and the robot hand 8 cannot be stopped accurately at the destination. Can not.

If this is a DC motor for discharging raw materials,
Too much raw material will be paid out.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device that can more accurately bring the rotation amount of a DC motor to be controlled closer to a target amount.

Means for Solving the Problems The motor control device of the present invention includes a first switching element interposed in series with a power supply circuit of a DC motor to be controlled,
A second switching element is connected in parallel to the power supply circuit of the DC motor, a pulse generator is attached to the output shaft of the DC motor, and a target value is compared with the number of pulses generated by the pulse generator to determine the first switching element. A first comparison section is provided that controls the second switching element and compares the target value with the number of pulses generated by the pulse generator, and the number of pulses generated by the pulse generator and a value 5 smaller than the target value are provided. - A second comparison section is provided to compare the pre-stop setting value of
The first switching element is turned on and the second switching element is turned off until the comparison section detects a match, and from when the second comparison section detects a match, the first comparison section detects a match. Over the period up to 1st. and a control section that turns off the second switching element and turns on the second switching element when the first comparison section detects a match. Features.

Effect: According to this configuration, the DC motor is energized until the number of pulses generated by the pulse generator attached to the output shaft of the DC motor reaches the pre-stop setting value, and after the energization ends, the DC motor rotates due to inertia. do.

When the DC motor rotates due to inertia and the number of pulses generated by the pulse generator reaches the target value, regenerative braking is applied to the DC motor, and the inertial rotation speed of the DC motor suddenly decreases and the rotation stops. do.

Embodiment 6 One embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Components having the same functions as those in FIG. 3 showing the conventional example will be described with the same reference numerals. FIG. 1 shows a motor control device of the present invention, which differs from that shown in FIG. 2 in the configuration of a control section 10 and the addition of a second comparison section 11.

In the second comparison section 11, the target value N. and a pre-stop set value N that is smaller than this target value No. 0 is compared. 1st. Based on the output of the second comparator 9.11, the first . Second
The control unit 10 that controls the switching elements 1 and 2 is configured as follows. First switching element 1 [
Refer to FIG. 2(b)] is controlled by the control unit 10, and when the second comparison unit 11 detects “NS>N o o”, the state is reversed from “ON” to “°ON”. The power supply to the DC motor M is terminated.

The second switching element 2 [see FIG. 2(C)]
When the comparator 9 detects 'Ns>No', it reverses from the "on" state to the "on" state and applies regenerative braking to the DC motor M.

Because of this configuration, the pre-stop setting value N. By setting 0 according to the characteristics of the DC motor M and the load, the first comparator 9 calculates the inertial rotation speed of the DC motor M such that llN5>No+1 as shown in FIG. 2(d). When detected, the speed is sufficiently reduced to V. In this state, by turning on the second switching element 2 and applying regenerative braking to the DC motor M, the control characteristics are improved compared to the conventional control characteristics shown by the broken line in Fig. 2(d). The rotation speed can be quickly brought to zero, reducing the amount of override compared to conventional robot hands.
The vehicle can be brought closer to the destination and stopped more accurately.

Pre-stop setting value N in the above embodiment. 0 may be set as an absolute amount, but in this case, this N may be set according to the change of destination.

Although it is necessary to change 0 each time, the target value N is a value n depending on the characteristics of the DC motor M and the load. Subtract N. If the configuration is configured to calculate 0, N will be calculated when the destination is changed. All you have to do is change the settings.

In the above embodiment, the case where the robot hand 8 is driven by the DC motor M was explained as an example, but the same applies to the case where the DC motor for dispensing raw materials is controlled, and the motor control device of the present invention can be adopted. As a result, the amount of raw material dispensed can be brought closer to the target amount more accurately.

Effects of the Invention As described above, according to the present invention, a first comparison section is provided for comparing the target value and the number of pulses generated by the pulse generator attached to the output shaft of the DC motor to be controlled, and A second comparison section is provided for comparing the number of pulses generated by the device with a pre-stop setting value that is smaller than the target value, and
．． Based on the output of the second comparison section, the first switching element connected in series with the power supply circuit of the DC motor to be controlled is turned on until the second comparison section detects a match; Since a control section is provided that turns the second switching element connected in parallel to the power supply circuit of the DC motor into the "neon" state from the time when the first comparison section detects a match, the second switching element is turned on. It is possible to sufficiently reduce the rotational speed of the DC motor when regenerative braking is applied in the "state" state, and the amount of override of the load driven by the DC motor can be reduced.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of a motor control device of the present invention;
FIG. 2 is a waveform diagram of a main part of the same device, FIG. 3 is a block diagram of a conventional motor control device, and FIG. 4 is a waveform diagram of a main part of a conventional device. M... DC motor, t... First switching element, 2... Second switching element, 6... Pulse generator, 8... Robot hand [controlled object], 9...
1st comparison section, 1O...Control section, 11...Second control section, No....Target value, No. ...Setting value before stopping.

Claims (1)

[Claims] 1. The first motor is connected in series to the power supply circuit of the DC motor to be controlled.
A switching element is inserted, a second switching element is connected in parallel to the power supply circuit of the DC motor, a pulse generator is attached to the output shaft of the DC motor, and the target value and the number of pulses generated by the pulse generator are determined. Compare the first and second
A first comparison unit is provided to control the switching element of the pulse generator and to compare the target value with the number of pulses generated by the pulse generator, and the number of pulses generated by the pulse generator before stopping is smaller than the target value. A second comparison section is provided to compare the set value, and until the second comparison section detects a match, the first
The first and second switching elements are turned on and the second switching element is turned off, and the first and second switching elements are turned on during the period from when the second comparison section detects a match until the first comparison section detects a match A motor control device comprising: a control section that turns off the first switching element and turns on the second switching element when the first comparison section detects a match.