JPH11275893A - System of switching control of multi-shaft motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost of a motor driving system at large by making the PWM circuit at the latter stage of the PWM output terminal of a CPU into a single piece. SOLUTION: This latter stage of the PWM output terminal 2 of a CPU 1 is provided with one piece of PWM circuit 5, and the output of this PWM circuit 5 is portioned out into plurality, and the latter stages of the above plurality of outputs of the PWM circuit 5 are provided with relays 7a-7c. Furthermore, the latter stages of the relays 7a-7c are provided with motors 4a-4c, respectively, and each relay 4a-4c is arranged to control the opening and closing of a contact by CPU 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control switching system for a multi-axis motor in which a single control center (for example, CPU) switches and controls a plurality of motors as appropriate.

[0002]

2. Description of the Related Art Generally, many CPUs (for example, so-called one-chip microcomputers) have one set (one unit) of motor power terminals. Hereinafter, this motor power terminal is referred to as a PWM output terminal. In general, six PWM output terminals are provided in one CPU, but these six PWM output terminals are integrated and treated as one PWM output terminal. . Conventionally, a single CPU has been used to switch and drive, for example, three motors (for example, a three-phase AC induction motor) in the following manner.

The first is a PWM circuit and a CPU for each motor.
Are associated one by one. Each C
If the PU is made communicable, the three CPUs can sequentially switch and control the three motors, and can simultaneously drive two or more motors. However, this method
Since the cost is high, especially when it is not necessary to simultaneously drive and control two or more motors, the following method is usually employed.

[0006] Three Ps are provided after the PWM output terminal of the CPU.
A WM circuit is provided, and three motors are respectively connected at the subsequent stage of each PWM circuit. The PWM circuit includes a transistor;
This is a conventional PWM wave motor drive and amplification & power supply circuit including a power element such as a diode. The CPU has the above 3
Addressing (designating the address) of the PWM circuits controls which PWM circuit is to be activated.

If the above-mentioned second conventional system is illustrated,
It will look like Figure 2. FIG. 2 is a block diagram showing a conventional multi-axis motor control system. The six PWM output terminals (2a to 2f) are respectively connected to PWM circuits (5a to 5f).
3C shows that the wires are wired one by one. Conventionally, three PWM circuits are required, which still increases the cost of the system, and the wiring is cumbersome.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the prior art, and has as its object to reduce the number of PWM circuits at the subsequent stage of the PWM output terminal of the CPU to one. Another object of the present invention is to provide a control switching method for a multi-axis motor that can reduce the manufacturing cost of the entire motor drive system.

[0007]

The control switching method of the multi-axis motor according to the present invention is as follows. CP
One PWM output terminal (there are multiple) of U
Provide a circuit. The PWM output terminal is connected to each P included in the PWM output as one unit of the CPU.
Normally there are six WM output terminals. The P
Outputs of the WM circuit are divided into a plurality of outputs, and relays (naturally, multi-pole contact relays) are provided at the subsequent stages of the plurality of outputs of the PWM circuit. A motor is provided at the subsequent stage of the relay, and each relay is wired and configured such that opening and closing of a contact is controlled by the CPU. For example, a relay or a coil of a relay is addressed and controlled.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Normally, one PWM circuit requires six input lines and three output lines. This is a so-called three-phase / complementary PWM circuit. CP suitable for recent motor drive
U typically has six PWM output terminals. One motor can be driven by one of the six PWM output terminals via one PWM circuit. In the present invention, the configuration from the CPU to the output stage of the PWM output circuit may be exactly the same as the configuration of the conventional motor drive system.

Output of PWM circuit (output of a set of three lines)
Is distributed to three outputs. The three outputs are controlled so that only one is always active. That is, the PWM is provided between the three motors and one PWM circuit.
One relay is provided for each of the three divided outputs of the circuit. Of course, this relay must have three pole contacts.

Only the motor connected to the relay whose contacts are closed is driven and braked. In the present invention, when performing feedback control of the motor, for example, an encoder may be provided for each of the three motors, and the detection signal may be fed back to the CPU.

[0011]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. The CPU 1 transmits (outputs) a motor drive / control signal to the PWM circuit 5 via six power (signal) lines via six PWM output terminals 2. The output of the PWM circuit 5 is 3
The three signal lines are relays (7a
To 7c). That is, each relay (7a-7)
From the viewpoint of c), it means that only the user himself is connected to the PWM circuit 5 by the three signal lines. In FIG. 1, only one pair of contacts of the relays (7a to 7c) is drawn for three signal lines.
a to 7c) have three pairs of contacts. That is, it is a three-pole relay.

Each relay (7a to 7c) has a CPU
1 controls the opening and closing of the contacts. For example, when the CPU 1 specifies an address assigned to each of the relays (7a to 7c), the coil L of the relay (7a to 7c) turns on / off.
What is necessary is just to make it off.

As described above, the CPU 1 controls the opening and closing of the relays (7a to 7c) having poles corresponding to the number of output lines of the PWM circuit 5, so that the PWM circuit 5, which is basically one output signal, Is output to a plurality of motors (4a to 4a).
It can be controlled by switching to c).

[0014]

Since the present invention is configured as described above, the following effects can be obtained.

The PWM at the subsequent stage of the PWM output terminal 2 of the CPU 1
The M circuit 5 is made into one, the output of the PWM circuit 5 is distributed to a plurality, and the CPU 1 controls the relay (7a
7c), the signals for driving and controlling the motors are transmitted to the respective motors (4a to 4c). Therefore, a control switching method for a multi-axis motor that can reduce the manufacturing cost of the entire motor drive system is provided. It is possible to

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional multi-axis motor control system.

[Explanation of symbols]

 Reference Signs List 1 CPU 2, 2a PWM output terminal 3 Number of signal lines 4a-4c Motor 5, 5a-5c PWM output circuit 6 Number of signal lines 7a-7c (three-pole) relay L Coil in relay

Claims (1)

[Claims] 1. A PWM circuit is provided at a subsequent stage of a PWM output terminal of a CPU, an output of the PWM circuit is divided into a plurality of outputs, and a relay is provided at a subsequent stage of the plurality of outputs of the PWM circuit, respectively. A control switching system for a multi-axis motor, wherein a motor is provided at a subsequent stage, and each of the relays is configured to control opening and closing of a contact by the CPU.