JPH07163182A - Motor control method and motor control device - Google Patents

Abstract

PURPOSE:To achieve an optimal control of a motor where the torque is not generated excessively from the motor by setting the control amount of the motor such that the motor torque follows up the fluctuation of device load due to the ambient temperature. CONSTITUTION:A control amount to be set for a motor driver 15 is preset on a control table 14 and an MPU 11 detects the device temperature through a temperature sensor 10 at a timing for setting the control amount of the motor driver 15. A target amount is then determined based on the device temperature and control command information being provided with reference to the control table 14. A comparator 16 in the motor driver 15 compares a voltage induced in a motor coil 19 with a preset reference value 17 and controls an output transistor 18 to match both voltages thus feeding the motor coil 19 with a constant current corresponding to the reference voltage 17. Consequently, the motor 9 is driven with a constant current to generate a predetermined torque for controlling the carriage of a carrier 8. This constitution controls the motor with an optimal motor torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a motor such as a DC motor or a stepping motor and a control device thereof, and in particular, in a device such as a printer in which the motor is incorporated, the temperature of the device over time during operation. The present invention relates to a motor control method and a control device capable of always operating the motor with a torque that is not wasted when the load of the motor is reduced.

[0002]

2. Description of the Related Art There are a constant voltage driving method and a constant current driving method as driving methods for stepping motors. For example, in order to operate the carrier of the printer, a motor that produces high torque at high speed is used. In such a motor, a constant current drive system is usually adopted.

One of the advantages of the constant current drive system is that in a comparator circuit that compares a feedback voltage from the coil with a reference voltage in order to drive the coil of the motor with a constant current, the reference voltage is adjusted to flow into the coil. The point is that the level of the constant current can be easily changed. By the way, since there is a direct proportional relationship between the coil current of the motor and the generated torque, the generated torque of the motor can be easily changed by adjusting the reference voltage.

In the motor control of the printer, this is used to change the constant current value of the coil according to the number of rotations of the motor, and, for example, as shown in FIG. In the carrier feed control including the deceleration region, control is performed to switch the constant current value of the coil in the slew up / down region to increase or decrease the motor torque.

The coil current of the motor is set to such a value that the torque required to drive the load of the apparatus is obtained, but in a low temperature environment where the apparatus temperature of the printer is 5 ° C. or lower,
Since the oil applied to the mechanism part solidifies and the load increases by 30% to 50% at room temperature, the conventional motor control method ensures that the coil current of the coil current can be reliably started even in a low temperature environment. Settings were being made. Figure 5
Shows the relationship between the generated motor torque and the variation of the device load due to the temperature in the case of such a conventional motor control method.

As is apparent from FIG. 5, the generated motor torque has an excessive torque margin with respect to the device load, that is, the torque actually required, particularly in the room temperature range.

[0007]

In the conventional motor control method, since the torque is set on the basis of the load that increases in a low temperature environment of the device, the torque becomes excessive during operation at room temperature, resulting in waste of power consumption. In addition to the above, there is a problem that heat generation and noise increase.

An object of the present invention is to optimally control the torque generated by the motor so as not to become excessive with respect to the fluctuation of the device load due to the difference in the operating environment temperature of the motor.

[0009]

According to the present invention, a control amount of a motor is set so that the torque generated by the motor follows the fluctuation of the device load due to the difference in the ambient temperature of the motor. Is.

FIG. 1 illustrates the principle of the present invention. Figure 1
1A shows the control characteristics of the motor control method according to the present invention, and FIG. 1B shows the schematic configuration of the motor control device according to the present invention.

In FIG. 1 (a), A shows a variation characteristic of the apparatus load due to a change in the operating environment temperature, and B shows a control characteristic of the motor torque with respect to the operating environment temperature change.

The control characteristic B of the motor torque is set so as to follow the variation characteristic A of the device load so that the motor torque is not generated more than necessary. Figure 1 (b)
Indicates a device configuration for realizing such a motor torque control characteristic B, where 1 is a motor to be controlled, 2 is
1 is a device load of a mechanism driven by the motor 1, 3 is a temperature sensor for detecting a use environment temperature of the motor, and 4 is a control characteristic of FIG. 1A corresponding to control instruction information for the motor 1 and the use environment temperature. A control table 5 for giving a control amount for generating an optimum motor torque such as B is a control unit for performing motor control.

The control unit 5 monitors the device temperature by the temperature sensor 3 during operation, and when the control instruction information for the motor 1 is given, the control instruction information and the use environment temperature detected by the temperature sensor 3 are used. Then, the control table 4 is referred to and the control amount at the corresponding position is read to control the motor 1. Here, the control amount is, for example, a reference voltage value that determines a constant current value that flows in the motor coil.

[0014]

As described above, the fluctuation of the device load caused by the change in the operating environment temperature as shown by A in FIG. 1A causes the oil to solidify at a low temperature such as 5 ° C. or less, which increases the device load. It is based on the fact that the fluidity of oil increases at room temperature to reduce the load on the equipment. Therefore, the required motor torque is large in the low temperature range and decreases in the normal temperature range. Since the control amount of the motor is set in the control table 4 shown in FIG. 1B in accordance with the motor torque required in this way depending on the ambient temperature of the motor, the temperature sensor 3 By changing the control amount read from the control table 4 according to the detected use environment temperature, it is possible to always generate a motor torque without waste.

[0015]

FIG. 2 shows an embodiment in which the present invention is applied to a printer. In FIG. 2, 6 is a printer, 7 is a platen,
8 is a carrier having a print head mounted thereon, 9 is a carrier feeding motor, 10 is a temperature sensor for detecting the temperature inside the apparatus, and 11 is a temperature sensor.
Is MPU, 12 is ROM, 13 is control program, 14
Is a control table for motor torque control, 15 is a motor driver, 16 is a comparator, 17 is a reference voltage, 18 is an output transistor, and 19 is a motor coil.

The MPU 11 executes print control of the printer by executing the control program 13. The control program 13 has a function of generating control instruction information for controlling the operation of the motor 9 with the carrier feeding control characteristics as shown in FIG. 4, for example, and the MPU 11 executes the control program 13 at a predetermined timing. Motor driver 1
Set the control amount for 5. Note that here, the motor operation mode information indicating the speed set for the motor 9 is used as the control instruction information.

The control amount set in the motor driver 15 is set in the control table 14. The MPU 11 detects the device temperature by the temperature sensor 10 at the timing of setting the control amount for the motor driver 15, and refers to the control table 14 based on the device temperature and the given control instruction information to determine the target control amount. Ask for.

The control amount set in the motor driver 15 is the value of the reference voltage 17 for controlling the constant current value flowing in the motor coil 19. The comparator 16 in the motor driver 15 compares the set reference voltage 17 with the voltage generated in the motor coil 19, controls the output transistor 18 so that the two voltages match, and responds to the value of the reference voltage 17. A constant current is applied to the motor coil 19.

As a result, the motor 9 is driven with a constant current, a predetermined torque is generated, and the carrier 8 is fed and controlled. 3A shows the flow of the motor control function part in the control program 13 of FIG. 2, and FIG. 3B shows the flow of FIG.
A specific example of the control table 14 of FIG. Hereinafter, details will be described with reference to FIG. 2 as necessary.

In the flow of FIG. 3A, when the power is turned on (ON), the temperature data of the temperature sensor 10 is first read, and the control instruction information of the motor previously generated by the control program 13 is read. (Motor operation mode information) is read. Next, with reference to the control table 14, the control amount corresponding to the temperature data and the control instruction information is determined and sent to the motor driver 15 to be executed. Of the above operations, the operation after the temperature data of the temperature sensor 10 is read is repeated every time the carrier feeding operation is performed.

Although the above embodiment relates to the control of the carrier feeding motor of the printer, the present invention is not limited to this, and any device in which the device load of the motor fluctuates depending on temperature is used. Can be similarly applied in.

[0022]

According to the present invention, even if the temperature in the device using the motor changes, the motor is controlled so that it operates with the motor torque commensurate with the device load at that temperature, so the power consumption of the motor is reduced. The heat generation amount or noise can be suppressed to the minimum value at all times, and the operation cost of the device can be reduced and the usage environment can be improved.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a configuration diagram of an embodiment in which the present invention is applied to a printer.

FIG. 3 is an explanatory diagram of a control program and a control table in the embodiment of the present invention.

FIG. 4 is a graph showing carrier feeding control characteristics of the printer.

FIG. 5 is a graph showing the relationship between the temperature fluctuation of the device load and the generated motor torque in the conventional motor control method.

[Explanation of symbols]

 1 Motor 2 Device Load 3 Temperature Sensor 4 Control Table 5 Control Section

Claims (2)

[Claims] 1. A motor control method for controlling a torque generated by a motor based on control instruction information, wherein a control amount of the motor with respect to given control instruction information is optimally changed according to a use environment temperature of the motor. And motor control method. 2. A motor control device for controlling a torque generated by a motor on the basis of control instruction information, a temperature sensor for detecting a use environment temperature of the motor, and a necessary and sufficient means for operating the motor based on the control instruction information. A control table that indicates various control amounts for each operating environment temperature of the motor, and the control table is referenced based on the given control instruction information and the operating environment temperature detected by the temperature sensor, and the corresponding control amount is read out. A control unit for controlling the motor,
A motor control device comprising: