JPH0483671A - System for controlling print head carriage movement - Google Patents

Abstract

PURPOSE:To suppress speed/vibration of a print head carriage with only a state quantity detector of a DC servo motor and hence to realize high speed movement by taking the difference signal between an output feedback signal and a state quantity feedback signal as a DC servo motor speed command signal. CONSTITUTION:A controlled DC servo motor revolution command signal is outputted with use of detected and estimated state quantities. A state quantity feedback multiplier 6 takes the above signal to multiply it by state feedback gains against respective state quantities obtained on the basis of an optimal regulator control law, thus obtaining a state quantity feedback signal 56. Furthermore, a target error signal detector 7 takes a print head carriage estimate speed signal 52 inputted from a state observation device 5, to output the difference signal between a print head carriage target speed and the same. Furthermore, a integral feedback gain multiplier 9 takes an addition signal of an obtained error signal 57 to a target error integrated signal which is integrated from the intial period at an integrator 8. Thereat, the above addition signal is multiplied by an integral feedback gain under the optimal regulator control law, thus obtaining an output feedback signal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control method for moving a seven-stroke carriage to printing in a printer that performs serial printing.

(Prior Art) In a serial printer, a motor and a print head carriage are connected by a wire or a flexible transmitter such as a heald, and the rotational motion of the motor is converted into linear motion to cause the print head carriage to reciprocate. However, such flexible transmitters tend to generate vibrations due to rapid acceleration or deceleration, resulting in a decrease in printing quality. Therefore, especially when performing high-speed printing, a control device is required that can move the print head carriage at high speed without generating speed vibrations.

Front carriage movement system for conventional printing? The 'i11 method is an open-loop control method in which the motor is driven in advance according to a profile suitable for the characteristics of the mechanical system.

However, as the print head carriage moves at higher speeds, variations in the parameters of the mechanical system may cause speed vibrations in the print head carriage movement. Therefore, a method was developed to respond to parameter fluctuations by installing sensors on the carriage and idle pulley to detect state quantities and perform feed hacking.

[Problems to be Solved by the Invention] In the conventional print head carriage movement control method described above,
It is possible to control the movement of the print head carriage in response to parameter fluctuations without generating speed vibrations, but when targeting personal users, such as in a serial printer, cost becomes an issue, making it impractical for low-priced printers. The problem was that it was not accurate.

An object of the present invention is to provide a print head carriage movement control system that solves these problems.

[Means for Solving the Problems] The present invention provides a print head carriage movement control system for a dot serial printer in which a DC servo motor is used as a drive source and the drive force is transmitted via a belt to reciprocate the print head carriage. The rotation angular velocity, rotation angular acceleration, and drive current of the DC servo motor drive amplifier are detected by each sensor, and the motor rotation angular velocity signal, motor rotation angular acceleration signal, and DC servo motor drive current signal are obtained respectively. The motor rotational angular velocity signal, motor rotational angular acceleration signal, and DC servo motor drive current signal are manually input to a state observation device designed using observer theory for the control target model, and the speed and acceleration of the print head carriage and the rotational angular velocity of the idle pulley are measured. and estimate the rotational angular acceleration,
The motor rotation angular velocity signal and the motor rotation angular acceleration signal obtained by obtaining and detecting the estimated carriage speed signal for printing, the estimated acceleration signal for the carriage for printing, the estimated idle pulley rotation angular velocity signal, and the idle pulley JIB constant rotation angular acceleration signal, and The optimal regulator state is set for each of the DC servo motor drive current signal, the estimated print head carriage speed signal and print head carriage estimated acceleration signal, the idle pulley 1fJI constant rotation angular velocity signal, and the idle pulley estimated rotation angular acceleration signal. A status feedback signal is obtained as the sum of the signals multiplied by the feedback gain, and the difference signal between the print head carriage target speed signal and the print head carriage estimated speed signal is added to the integrated error signal that has been integrated from the initial point in time. The present invention is characterized in that an output feed hack signal is obtained by multiplying by a combined integral feed hack gain, and a difference signal between the output feedback signal and the state feedback signal S is used as a DC servo motor speed command signal of a DC servo motor drive amplifier.

〔Example〕

Specific embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic diagram of a dot serial printer to which the present invention is applicable. In FIG. 2, the serial printer uses a print head 2 to print paper mounted on a platen 26.
Printing is performed using 0. Print head 20 is fixed to print head carriage 25 .

Printhead carriage 25 reciprocates on linear guide 27 parallel to platen 26 . The print head carriage 25 is moved by receiving the rotational force of the DCC servomorph 2 via the motor pulley 22, idle booby IJ 24, and heald 23.

Normally, the print head carriage movement mechanism is configured like this,
Printing is performed by applying a print signal to the print head while the print head carriage is moving. In addition, the DC servo motor 21
The state quantity is detected by the tacho generator 28.

FIG. 1 is a block diagram showing the configuration of an apparatus to which the print head carriage control method of the present invention is applied.

This device controls the rotation of the DC servo motor 21 to control the speed of the print head carriage 25 in the print head carriage moving mechanism described above with reference to FIG. The purpose of controlling the speed of the print head carriage 25 is to make it follow the target speed in a short period of time without generating residual vibrations.

Therefore, the print head carriage movement control method of the present invention configures a control system using an optimal regulator control law. The state quantity to be detected for configuring the optimal regulator control system is
These are a DC servo motor drive current signal, a motor rotation angular velocity signal, and a motor rotation angular acceleration signal.

Further, the undetected printing head 1 to carriage speed signal, print head carriage acceleration signal, idle pulley rotation angular velocity, and idle pulley rotation angular acceleration are estimated by the state observation device.

A print head carriage movement control system for outputting a DC servo motor rotational speed command signal as a control variable using these detected state quantities and estimated state quantities is configured as follows.

The print head carriage moving mechanism section 1 in FIG. 1 has the configuration shown in FIG. 2, and the input is a DC servo motor drive amplifier 2.
This is the drive current given to the DC servo motor 21 from the tachometer generator (rotary encoder).
28 detection signals.

This detection signal is detected by the DC servo motor state quantity detector 3, which outputs a motor rotational angular velocity signal 50 and a motor rotational angular acceleration signal 45.
Convert to The obtained signal is taken into the state observation device 5. Further, the motor rotation angular velocity signal 50 is also taken into the DC servo motor drive amplifier 2. A DC servo motor drive current signal 51 indicating the drive current applied to the DC servo motor 21 is outputted from the DC servo motor drive amplifier 2 via the drive current detector 4 and taken into the state observation device 5 . Furthermore, the state quantity observation device 5 also takes in the DC servo motor rotation speed command signal 46 input to the DC servo motor drive amplifier 2, print head carriage speed signal 52, print head carriage acceleration signal 53, idle pulley rotation angular velocity signal 54, and idle pulley rotation angular velocity signal 54. The rotational angular acceleration signal 55 is estimated.

The DC servo motor drive current signal 51 and the DCC servo morph turning angular velocity signal 50, D detected as described above.
C servo motor rotation angular acceleration signal 45, estimated print head carriage speed signal 52 and print head carriage acceleration signal 53, and idle pulley rotation angular speed signal 5.
4 and the idle pulley rotation angular acceleration signal 55 are taken into a state feedback gain multiplier 6, and each signal is multiplied by the state feedback gain for each state quantity obtained by the optimal regulator control law to obtain a state feedback signal 56. In addition, the print/gutter carriage estimated speed signal 52 output from the condition observation device 5 is taken into the target error signal detector 7, which outputs a difference signal from the target speed of the print head carriage. Furthermore, the sum signal of the obtained error signal 57 and the target error accumulation signal that has been integrated from the initial point in time by the integrator 8 is taken into the integral feedback gain multiplier 9. Here, the output feedhack signal 58 is obtained by multiplying by the integral feedback gain obtained by the optimal regulator control law. The resulting output feed hack signal 58
and the status feed signal 56 are taken into the subtracter 10, and the difference signal between both signals is given to the DC servo motor drive amplifier 2 as the DC servo motor rotational speed command signal 46.

FIG. 3 is a diagram showing the configuration of a drive amplifier 2 for a DC servo motor used in a printing head carriage movement control device to which this method is applied. This drive amplifier receives a rotation angular velocity signal 50 of the DC servo motor 21 obtained from the output signal of the tacho generator 28 via the DC servo motor state quantity detector 3, and a motor rotation speed command signal 46 from the subtractor 10. The input is the drive current 48.49 to the DC servo motor 21 as the output.

The morph rotational speed signal 50 and motor rotational speed command signal 46 input to the DC servo motor drive amplifier 2 are converted into a control signal 47 by the speed controller 42, and the current amplifier 41 converts the morph rotational speed signal 50 and motor rotational speed command signal 46 into a control signal 47.
It is converted into a servo motor drive current of 48.49 and applied to the DC servo motor 21. That is, the speed controller 42 amplifies the difference between the rotational speed signal 50 and the rotational speed command signal 46 and converts it into a control signal 47. The current amplifier 41 generates a drive current 48 by PWM drive or DC amplification according to the control signal 47.
．． Convert to 49.

FIG. 4 is a detailed block diagram of the state observation device 5 in FIG. 1. Blocks 60, 61, 63, and 64 each receive each state quantity signal inputted with each coefficient matrix BL, A, and C, which are derived for the state equation and detection equation of the print head carriage moving mechanism below, according to the Kalman filter observer theory. It is a multiplier that multiplies by.

The state equation and detection equation of the printing gutter carriage moving mechanism system are as follows. Here, x (k) is a vector consisting of state quantities representing the drive current, DC servo motor rotation angular velocity, DC servo moke rotation angular acceleration, printing hend carriage speed, printing hend carriage acceleration, idle pulley rotation angular velocity, and idle pulley rotation angular acceleration. , y (k) is the state quantity drive current detected among the elements of x (k),
Vectors consisting of the DC servo motor rotation angular velocity and DC servo motor rotation angular acceleration, A and B are the system matrix and input matrix derived from the equation of motion of the print head carriage, and C is the detection of y (k) from x (k). This is an observation matrix that extracts only state quantities.

The configuration and operation of each of the following two blocks can be easily inferred by those skilled in the art, and further detailed explanation will be omitted.

(Effects of the Invention) According to the present invention, the DCC servo morph is The speed vibration of the printing head carriage can be suppressed using only the P1i detector, and it can move at a higher speed than before.Therefore, it is possible to provide a control device that speeds up the printing and gutter carriage movement at a low cost. It can enable the development of affordable dot serial printers.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a device to which the print head carriage control method of the present invention is applied, Fig. 2 is a schematic diagram of a dot serial printer to which the method of the present invention is applied, and Fig. 3 is a diagram to which the method of the present invention is applied. FIG. 4 is a detailed block diagram of the condition observation device. 1...Print head carriage mechanism section 7...
・ ・ 9 ・ ・ ・ ・ ・ 8 ・ ・ ・ ・ DC servo motor drive amplifier DC servo motor state quantity detector Drive current detector Status observer Status feedback gain multiplier Target error signal detector multiplier Integral feedback gain multiplier

Claims (1)

[Claims] (1) In a print head carriage movement control system for a dot serial printer that uses a DC servo motor as a drive source and transmits driving force via a belt to reciprocate the print head carriage, the rotational angular velocity and rotational angular acceleration of the motor, D
The drive current of the C servo motor drive amplifier is detected by each sensor, and a motor rotation angular velocity signal, a motor rotation angular acceleration signal, and a DC servo motor drive current signal are obtained respectively.Observer theory is also applied to the control target model of the print head carriage drive system. Input the motor rotational angular velocity signal, motor rotational angular acceleration signal, and DC servo motor drive current signal into the state observation device designed in , and estimate the speed and acceleration of the print head carriage and the rotational angular velocity and rotational angular acceleration of the idle pulley. A print head carriage estimated speed signal, a print head carriage estimated acceleration signal, an idle pulley estimated rotation angular velocity signal, and an idle pulley estimated rotation angular acceleration signal are obtained, and the motor rotation angular velocity signal, motor rotation angular acceleration signal and DC obtained by detection are obtained. Optimum regulator state feedback gain for each of the servo motor drive current signal, the estimated print head carriage speed signal and print head carriage estimated acceleration signal, the idle pulley estimated rotational angular velocity signal, and the idle pulley estimated rotational angular acceleration signal. A state feedback signal is obtained as the sum of the multiplied signals, and the difference signal between the print head carriage target speed signal and the print head carriage estimated speed signal is added to the integrated error signal that has been integrated from the initial point of time to obtain an integral feedback gain. A print head carriage movement control method characterized in that a multiplied output feedback signal is obtained, and a difference signal between the output feedback signal and the state feedback signal is used as a DC servo motor speed command signal of a DC servo motor drive amplifier.