JPH0691977A - Motor control apparatus - Google Patents

Abstract

PURPOSE:To obtain good characteristics by calculating the initial value of control parameter from a detected data and making it converge into an optimum value quickly in the motor control apparatus of a serial printer or the like. CONSTITUTION:The operating speed of a control objective 5 is detected by speed detecting means 6, and then it is converted into a speed data. The data is sent to data retaining means 7 and a speed subtracter 9. Speed errors Ve are calculated and forwarded to PID control means 1. The data sent to the data retaining means is retained at a designated timing. The voltage output from a vacuum sensor is inputted in MPU through an A/D converter, and converted into ink residual quantity. At an initial value calculator 11, the initial value of the control parameter is calculated. Then, the duty of PWM is calculated, and a carriage is driven by the value, and by repeating these operations, it is brought near an optimum value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device, and more particularly to a motor control device used in, for example, a printer or a facsimile.

[0002]

2. Description of the Related Art Conventionally, in a serial printer (hereinafter referred to as "conventional example"), a DC motor and its controller are used as a drive source for scanning a carriage carrying a printing means such as a dot impact method, an ink jet method, a thermal transfer method, etc. Is used. When receiving print data from an external computer or the like, a general serial printer starts motor rotation for driving the carriage, and starts printing when a certain speed is reached. When printing one line of data, stop the motor,
The paper for one line is fed. Further, if there is print data, the above operation is repeated to continue printing. Here, the operation of the carriage drive motor (hereinafter referred to as CR motor) will be described in detail.

FIG. 5 is a block diagram showing a PID control of a conventional serial printer (hereinafter referred to as a printer), FIG. 6 is a block diagram showing a learning servo of a conventional example, and FIG. 7 is an example of a conventional carriage speed control. FIG. 8 is a diagram showing an example of obtaining a velocity signal from an encoder pulse of a conventional example.

First, when a print start command is sent from the computer, the printer controller activates the CR motor via the motor control device. For example, as shown in FIG. 7, immediately after starting, the vehicle is gradually accelerated so that noise or vibration does not occur or overcurrent does not flow to the motor (acceleration region a). Then, constant speed control is performed at a predetermined speed and printing is performed (constant speed area b). After printing is completed, the speed is decelerated (deceleration area c) and stopped. That is, in the acceleration range a and the deceleration range c, noise is not generated due to abrupt speed fluctuations, and in the constant speed range b, the printing accuracy is not disturbed.

The speed control of the CR motor as described above is shown in FIG.
It is generally performed by a servo system having a PID control loop as shown in the block diagram of FIG. 1, and finally, it is performed by changing the voltage applied to the motor or the duty of PWM.

Here, description will be made assuming that the PWM duty is controlled to control the motor speed. First, the speed error Ve is calculated by subtracting the moving speed of the controlled object (carriage in this case) or the rotation speed of the motor detected by a speed detection mechanism such as an encoder from the externally instructed speed. Next, for example, the operation amount (here, the duty of PWM) is calculated according to the following equation.

PWM = Kp × Ve + Ki × ∫Vedt + Kd × (dVe / dt) where Kp ... Proportional control constant Ki ... Integral control constant Kd ... Differential control constant. The duty of PWM applied to the motor driver is changed according to the calculated value to control the speed of the carriage.

The above description is based on the control parameters Kp, Ki,
Although Kd is fixed, it can be changed dynamically.
A so-called learning servo system can also be adopted. FIG. 6 shows this block diagram. This method has a means for holding all or part of the detected speed data, and calculates and sets a control parameter that is closer to the optimum from these data. In addition, the carriage is reciprocated several times to gradually converge to the optimum value. In this case, good control characteristics are often obtained even with relatively large load fluctuations.

In recent years, microprocessors (hereinafter referred to as MPUs)
The above-mentioned control is performed by digital control using an MPU.
In this case, the initial values of the above Kp, Ki, and Kd parameters are stored in the ROM, and the calculated set values are stored in the RAM.

[0010]

Color printers are usually yellow (Yellow), magenta (Magenta), and cyan (Cya).
It has multiple heads, such as n) and Black, and mixes these colors on the paper surface to express other colors. Of course,
It is also possible to express many colors in a pseudo manner by using an area gradation method such as a dither method. When a carriage is equipped with a plurality of heads and a plurality of ink tanks to configure this color printer, the ink is consumed and the weight of the carriage changes as printing is performed. In the case of a color printer equipped with a plurality of colors of ink, the change is particularly large. In this case, even if the carriage is reciprocated and the learning servo is performed, the calculation of the control parameter is divergent, and even if the calculation is converged, the carriage reciprocates many times, which causes a practical problem.

The present invention has been made to solve the above problems, and an object of the present invention is to calculate initial values of control parameters from detected data and quickly converge them to optimum values to obtain good control characteristics. And

[0012]

Therefore, according to the first aspect of the present invention, the operating speed detecting means for detecting the operating speed of the controlled object and the parameter for calculating and setting the control parameter from the data of the detecting means. In a motor control device having a setting means and a learning servomotor control means for converging to an optimum control parameter for each operation, a weight detection means for detecting the weight of the controlled object, and a detection result of the weight detection means It is an object of the present invention to solve the above problems and achieve the above objects by a motor control device including an initial value setting means for setting an initial value of a control parameter.

According to a second aspect of the present invention, in a carriage motor control device of a printing device for scanning a carriage having a plurality of ink jet heads, the ink consumption amount or the ink remaining amount in an ink tank mounted on the carriage is increased. An object of the present invention is to solve the problems and achieve the object by a motor control device according to claim 1, wherein an amount is detected and an initial value of the control parameter is set based on the detected value.

[0014]

In the motor control device according to the present invention, the weight detection means detects the weight of the object to be controlled, and the initial value setting means sets the initial value of the parameter setting means based on the detection result of the weight detection means.

The motor control device according to another invention of the present invention, in the above-mentioned invention, detects an ink consumption amount or an ink remaining amount in the ink tank mounted on the carriage, and detects the initial value of the control parameter based on the detected value. Set the value.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS. The first embodiment relates to carriage control of an ink jet type serial color printer.

FIG. 1 is a block diagram showing the constitution of a motor control device according to the first embodiment of the present invention, and FIG. 2 is a constitution diagram showing the ink tank remaining amount detecting means of the first embodiment.

In FIG. 1, the operating speed of the controlled object 5 is detected by speed detecting means 6 such as an encoder. For example, when speed detection is performed by an encoder, the interval between consecutive encoder pulses as shown in FIG. 8 is counted based on a clock from a clock generator (not shown), and speed data is calculated from this count value and clock frequency. Convert to. The speed data is sent to the data holding means 7 and the speed subtractor 9. The data sent to the speed subtractor 9 is subtracted from the speed instruction data input from the outside, and the speed error Ve is calculated and sent to the PID control means 1. The speed data sent to the data holding means 7 holds a required amount of data at a designated timing by a signal given by a data holding timing generating means (not shown).

The held data is sent to the control parameter calculation means 8. The remaining ink amount detection is configured using, for example, a known negative pressure sensor 14 as shown in FIG. The voltage output from the negative pressure sensor 14 is input to the MPU 18 through the A / D converter 17 and converted into the ink remaining amount by the conversion table of the voltage output and the ink remaining amount obtained in advance by experiments or the like. This conversion table is generally written in the ROM.

This makes it possible to estimate the weight of the carriage, which is a load on the motor. Based on this, the initial value calculation means 11 calculates the initial value of the control parameter. This can also be done by writing the initial value data obtained by experiments or the like in the ROM or the like and referring to it. The obtained initial values of the control parameters are sent to the control parameter calculation means 8. In the control parameter calculation means 8, the data holding means 7
The values of the PID control parameters Kp, Ki, Kd are calculated on the basis of the data from and the initial value from the initial value calculation means 11,
Set in the PID control means 1. The PID control means 1 calculates the PWM duty to be applied to the motor driver 3 by the calculation formula PWM = Kp × Ve + Ki × ∫Vedt + Kd × (dVe / dt) as described in the conventional example. The carriage is driven with the PWM value calculated in this way, and the control parameters are recalculated based on the speed data. By repeating this, the value approaches the optimum value.

Next, a second embodiment of the present invention will be described with reference to FIG.
Will be explained. FIG. 3 is a block diagram showing the ink remaining amount detecting means of the second embodiment of the present invention.

In FIG. 3, data sent from an external computer 19 is taken into a reception buffer 21 in the printer via an interface (I / F) 20 such as Centronics. Since this is performed in parallel with other operations of the printer, it is often performed by hardware or interrupt processing. The data in the reception buffer 21 is a control code, a character code, and image data. In the case of the control code, the designated operation is performed. For character codes, the character generator in the printer (usually R
The dot data of the corresponding character is extracted from (in the OM) and written in the print buffer 22. In the case of image data, it is written in the print buffer 22 after being converted into a data format suitable for printing. That is, the print pattern is written in the print buffer 22, and the total number of print dots can be known by counting the number of "1" bits or the number of "0" bits in the print pattern. The quantity can be estimated. This counter can be easily implemented in hardware or software. In this case, it is written in the nonvolatile RAM or the like so that the accumulated print dot number up to that point is not erased when the power is turned off. The other operations are the same as those in the first embodiment, and the duplicated description will be omitted.

Also in the second embodiment, the same operation and effect as in the first embodiment can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing the ink remaining amount detecting means of the third embodiment of the present invention.

In FIG. 4, the print pattern data stored in the print buffer 22 as described in the second embodiment is transferred to the print head 24 serially or in parallel. By providing a counter 23 for the number of bits of "1" or the number of bits of "0" in the middle of this transfer path, the total number of print dots can be counted. The other operations are the same as those in the first embodiment, and the duplicated description will be omitted.

Also in the third embodiment, the same operation and effect as those of the first embodiment can be obtained.

[0027]

As described in detail above, according to the present invention, the means for detecting the remaining ink amount is provided, and the initial value of the control parameter is calculated from the data, whereby the value quickly converges to the optimum value. The effect is very large because good control characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a motor control device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing an ink tank remaining amount detecting means of the first embodiment.

FIG. 3 is a configuration diagram showing an ink tank remaining amount detecting means of a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing an ink tank remaining amount detecting means of a third embodiment of the present invention.

FIG. 5 is a block diagram showing PID control of a conventional printer.

FIG. 6 is a block diagram showing a learning servo of a conventional example.

FIG. 7 is a diagram showing an example of speed control of a conventional carriage.

FIG. 8 is a diagram showing an example of obtaining a velocity signal from a conventional encoder pulse.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PID control means 2 PWM control means 3 Motor driver 4 Motor 5 Control object 6 Speed detection means 7 Data holding means 8 Control parameter calculation means 9 Speed subtraction means 11 Initial value calculation means 12 Ink remaining amount detection means 13 Ink tank 14 Negative pressure Sensor 15 Print head 16 Ink flow path 17 A / D conversion means 18 MPU 19 Computer 20 Interface 21 Receive buffer 22 Print buffer 23 Dot counter 24 Print head

Claims (2)

[Claims] 1. An operating speed detecting means for detecting an operating speed of a controlled object, a parameter setting means for calculating and setting a control parameter from data of the detecting means, and a learning for converging to an optimum control parameter for each operation. In a motor control device having a servo motor control means, a weight detection means for detecting the weight of the controlled object, and an initial value setting means for setting an initial value of the control parameter according to a detection result of the weight detection means. A motor control device comprising: 2. A carriage motor control device of a printing device, which scans a carriage having a plurality of ink jet heads, detects an ink consumption amount or an ink remaining amount in an ink tank mounted on the carriage, and uses the detected value. The motor control device according to claim 1, wherein an initial value of the control parameter is set.