JPH01249373A - System for controlling movement of printing head of printer - Google Patents

Abstract

PURPOSE:To suppress the residual vibration and speed vibration of a printing head carrier after the change of the speed state of said carrier, by driving a motor on the basis of the optimum driving profile until the printing head carrier becomes a constant speed state from a stop state and becomes the stop state from the constant speed state and performing speed control by state feedback in the constant speed state using the optimum feedback gain to the model of a drive system. CONSTITUTION:Until a printing head carrier becomes a constant speed state from a stop state and becomes the stop state from the constant speed state, a motor is driven according to the optimum driving profile of the speed of the motor, wherein the energy of driving force changing a state becomes min., for the time applied to the physical model of a drive system consisting of the motor, a flexible transmitter and the printing head carrier. When the printing head carrier is driven at a constant speed, the optimum feedback gain not imparting the effect due to the printing impact by a printing hammer to the movement of the printing head carrier is calculated according to the optimum regulator rule to apply state feedback to the model of the drive system and the speed of the drive system is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printer print head movement control system, and more particularly to a control system for moving a print head carrier in a printer that performs serial printing.

[Conventional technology]

The print head carrier of the printer is moved by connecting the motor and the print head carrier with a flexible transmitter (wire, belt, etc.) and converting the rotational movement of the motor into linear movement of the carrier.

However, when the flexible transmitter is rapidly accelerated or decelerated, it generates vibration, which deteriorates printing quality. Therefore, especially when performing high-speed printing, accurate positioning control of the print head carrier is required.

Some conventional print head carrier positioning control systems use a control device in which the print head carrier is provided with a position detector capable of measuring the absolute position.

There are two methods for this control method. One is to treat the position information of the print head carrier as a print command.

The other method is to adjust the speed of the print head carrier based on the error between the detected position information and the target position to be printed, and perform positioning. For example, the former is
No. 16880 "Printer", the latter is JP-A-60-2
No. 36781 "Control Method for Serial Printer".

[Problem to be solved by the invention]

In the former (2) printer control device, the higher the speed, the more time lag occurs between the time when the position of the print head carrier is detected and the time when printing is performed.

Therefore, when the print head carrier is at a constant speed, accurate printing can be performed, but when the flexible transmitter is vibrating, printing errors may occur.

In the latter control method for serial printers, the vibration of the flexible transmitter is not actively controlled when the print head carrier is changed from a stopped state to a constant speed state or when the print head carrier is changed from a constant speed state to a stopped state. In such a state, position control is impossible, and there is a problem that printing is not possible until the vibration of the flexible transmitter subsides, resulting in wasted time.

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

[Means to solve the problem]

The printer print head movement control method of the present invention is applicable to a printer in which a motor and a print head carrier are connected by a flexible transmitter, from when the print head carrier changes from a stopped state to a constant speed state, and from a constant speed state to a stopped state. is determined according to an optimal drive profile for the speed of the motor that minimizes the energy of the drive force that changes state in a given time for a physical model of the drive system consisting of the motor, flexible transmitter, and printhead carrier. When the motor is driven and the print head carrier is at a constant speed, the optimal feedback gain is determined using the optimal regulator law for the drive system model so that the printing impact caused by the printing hammer does not affect the movement of the print head carrier. It is characterized in that the speed of the drive system is controlled by feedback.

[Effect]

In the present invention, the motor is driven according to the optimum drive profile until the print head carrier changes from a stopped state to a constant speed state and from a constant speed state to a stopped state. At this time, it is necessary to suppress the generation of residual vibrations after the state of the print head carrier changes. Following this optimal drive profile minimizes the energy of the driving force to change the state of the printhead carrier within a given period of time, eliminating excess energy that could induce instability after a state change. With this method, the time required for the print head carrier to change from an accelerated state to a constant speed state or from a decelerated state to a stopped state is shortened, and the constant speed is increased to a high speed, resulting in a high-speed print head carrier that suppresses residual vibration after a state change. The movement can be realized.

Furthermore, when the print head carrier is at a constant speed, it is necessary to maintain a stable state by excluding the influence of the print impact of the print hammer, which acts as a disturbance to the movement of the print head carrier. The optimum feed rate and gain, which are sufficiently robust against the influence of the printing impact of printing marks, are determined from the optimum regirator law, and the speed is controlled by state feedback.

As a result, the constant speed state of the moving print head carrier is stably maintained, and the printer can print at a predetermined position according to a print command at fixed time intervals.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a schematic diagram showing the configuration of a drive control device and a print control device of a printer to which the method of controlling movement of a print head carrier of the present invention is applied.

In FIG. 3, a printer control device 30 controls all operations of the printer, and a drive profile generator 33 or motor drive control device 34 is controlled by drive commands from the printer control device 30 and controls the movement of the print head carrier. do. The drive profile generator 33 or the motor drive controller 34 is selected by a switch 35 depending on whether the print head carrier is in an acceleration state, a deceleration state, or a constant speed state. The drive device 36 generates a drive profile generator 33 or a motor drive control device 3.
The motor drive command value generated in step 4 is converted into a signal for driving the motor 37. The flexible transmitter 40 is connected to the motor 3
The power generated at 7 is transmitted to the print head carrier 41.

A rotary encoder 38 and a tacho generator 39 are connected to the motor 37, and a state quantity detection device 45 connected thereto detects the state quantity of the motor. Further, a linear sensor 42 is connected to the print head carrier 41, and a position signal generator 43 and a speed signal generator 44 connected thereto generate signals representing the state quantity of the print head carrier.

The state quantity detection device 45 detects the state quantity of the print head carrier. This state quantity detection device 45 is connected to the printer control device 301, the drive profile generation device 33, and the drive system control device 34, and feeds back the state amount of the drive system consisting of the motor, flexible transmitter, and print head carrier to each of these devices. .

Also, the print control device 3 connected to the printer control device 30
1 sends a print command to the print head 32.

FIG. 4 is a block diagram showing the configuration of the printer drive control device from when the print head carrier changes from a stopped state to a constant speed state and from a constant speed state to a stopped state.

In FIG. 4, the drive profile generator ff1it33 is selected as described in FIG. 3. In addition, the necessary state quantities are the rotational speed of the motor 37 and the print head carrier 41.
Therefore, among the state quantity detection devices of the print head carrier 45, only the motor rotational speed detection device 45a connected to the tacho generator 39 and the position detection device 45d connected to the position signal generation device 43 are used. The motor rotation speed detection device 45a and the position detection device 45d are connected to the drive profile generation device 33 and the printer control device 30, respectively, and feed back the rotation speed of the motor 37 and the position of the print head carrier 41.

FIG. 5 is a diagram showing the configuration of the drive control device and print control device of the printer when the print head carrier is in a constant speed state.

In FIG. 5, the drive system control device 34 is selected as described in FIG. Further, since the necessary state quantities are the rotational speed of the motor 37 and the position, speed, and acceleration of the print head carrier 41, the motor rotational speed detection device 45a connected to the tacho generator 39 in the state quantity detection device 45 and the position signal A position detection device 45d connected to the generator fi7t, 43, a speed detection device 45b connected to the speed signal generation device 44, and an acceleration detection device 45C are used. The motor rotation speed detection device 45a, speed detection device 45b1, and acceleration detection device 45C are connected to the drive system control device 33, and feed back the rotation speed of the motor 37 and the speed and acceleration of the print head carrier 41.

The position detection device 45d is connected to the printer control device 30,
The position of the print head carrier 41 is fed back.

Note that the printing impact of the printing hammer on the printing head 32 affects the movement of the printing head carrier 41 as a disturbance.

Next, how to control the print head carrier movement of the present invention using the drive control device and print control device of the printer described above.
Explain 'l.

FIG. 1 is a diagram showing the procedure of a print head carrier movement control system for a printer according to the present invention.

In order to move the print head carrier at a predetermined printing speed, it is accelerated from a stopped state to a constant speed state.

During this acceleration, the motor is driven in step 2 according to a predetermined motor drive profile. In step 3, it is determined whether the drive profile is finished or not, and steps 2 and 3 are repeated until the drive profile is finished.

From the time the print head carrier reaches a predetermined printing speed until the end of printing, the speed control in step 4 is performed by state feedback using a predetermined optimal feedback gain to maintain a constant speed state. Then, printing in step 5 is performed at regular intervals. In step 6, it is determined whether or not printing is finished, and steps 4, 5, and 6 are repeated until printing is finished.

To stop the printhead carrier, it is decelerated from a constant speed state to a stopped state. During this deceleration, the motor is driven in step 7 according to the motor drive profile determined in advance. In step 8, it is determined whether the drive profile is finished or not, and steps 7 and 8 are repeated until the drive profile is finished.

Next, an embodiment will be described about how to obtain the drive file used when the print head carrier changes from a stopped state to a constant speed state or from a constant speed state to a stopped state.

The drive profile consists of motor drive command values at fixed time intervals between the time when the state change of the print head carrier starts and the time when the state change ends.

FIG. 2 is a diagram showing a physical model of the drive system consisting of the motor, flexible transmitter, and print head carrier. This example uses a DC servo motor. The command voltage input to the input section 11 is current-amplified by the servo amplifier 12 and sent to the coil (L) in the DC servo motor 37.
: inductance) 14 as a current. This causes the load (J: moment of inertia) 16 to generate power.

This power is transmitted through a flexible transmitter (k: spring constant) 40 and moves the print head carrier 41. At this time, friction (C:
A friction coefficient of 19 occurs.

From this model, the following state equation, x (t) =Ax (t) +B u (t)
−”'(1)y (t) =Cx (t)
...(2) is derived. Here, u (t): Command value x (t) to the servo amplifier: I
V,,,V. volt Vrn: Speed of the motor at the outer periphery of the pulley v0: Speed of the print head carrier B=1 0m o oltC=1
0 1 01β −J β : Viscosity coefficient ω1=no. For the state equations (1) and (2), the optimal control function u'(t) that minimizes the following evaluation function is found from the maximum principle. where: tl: Acceleration acid of printhead carrier is deceleration time.

This optimal control function u'(t) becomes the optimal driving function.

Next, in the present invention, when the print head carrier is in a constant speed state, speed control is performed using the optimal regulator law, and a method for determining the optimal feedback gain will be explained.

The optimal regulator is applied to a physical model of a drive system consisting of a motor, a flexible transmitter, and a print carrier. First, the state equation of the DC servo motor in (1) is discretized.

x (k+1)=A' x (k)+B' u(k)
−...(4) y (+<)=c' x (k)
......(5) Here, Δt is the sampling time, and x(t)=x()cJt) y(t)=y(kΔt) u(t)=u(kΔt), A' = exp (AΔt) B'=f exp (At) Bdr Ct=C. Here, (A', B/, C' in equation (5)
) to (A, B, C). Then, the difference g between the target speed of the RAD carrier and y(k) (=■o) during printing
(k)=ry(k)...
・(6) and 9, variation of drive command value V(k) = u (k+1) −u (k)
""" (7) and the variation of the state quantity as ξ(k)=x(k+1)-x(k) ・-(
8), we can construct an expanded system as follows. Here, the optimal regulator law is applied. Consider the evaluation function (11) for equations (6) and (7). Here, Q and R are fixed symmetric matrices.

Here, for ease of understanding, it is replaced with H=CB'03' C=Co I). Here, if the system (A, B, C) is reachable and observable, the Riccati algebraic equation % has a unique fixed symmetric matrix, and the optimal human power to minimize J[v] in equation (11) Vo (k) is (K K1)=
-(B'PH+k(,)"B'PA......(14
) is given by. Here, (K Kl:] is the optimal feedback gain. The control system at this time is Vo (
The original control input u 6 (k) = K x (k) + K s , 2g corresponding to k)
(i)+[u6 (0)-Kx(k):]IceO (15). By adjusting the parameters Q and Q, an optimal feedback gain is determined that allows the movement control of the print head carrier to be sufficiently robust against the influence of the printing impact of the printing hammer.

The above description of the method for controlling the movement of the print head carrier of the printer of the present invention can be easily inferred by those skilled in the art, and further detailed explanation will be omitted.

〔Effect of the invention〕

According to the present invention, the motor is driven by an optimal drive profile until the print head carrier changes from a stopped state to a constant speed state and from a constant speed state to a stopped state, and when the print head carrier reaches a constant speed state or stops. Does not generate residual vibration when the condition is reached. In addition, in a constant speed state, an optimal regulator is applied to the drive system model consisting of the motor, flexible transmitter, and print head carrier, and the optimal feedback gain is determined so that the printing impact of the printing hammer does not affect the movement of the print head carrier. By controlling the speed using state feedback, it is possible to suppress speed vibrations of the print head carrier caused by printing.

According to the present invention described above, a print head carrier movement control device that solves the above-mentioned conventional problems can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a procedure for controlling the movement of a print head carrier in a printer according to an embodiment of the present invention, and FIG. 2 is a diagram showing a motor, a flexible transmitter, and a print head of a printer according to an embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of a drive control device and a print control device of a printer to which a print head carrier movement control method according to an embodiment of the present invention is applied. , FIG. 4 shows the printer drive 1+:! from the stop state to the constant speed state of the print head carrier and from the constant speed state to the stop state. FIG. 5 is a block diagram showing the configuration of the printer drive control device and print control device when the print head carrier is in a constant speed state. 30...Printer control device, 31...
Print control device, 32...Print head, 33...
... Drive flow file generator, 34...
Drive system control device, 35... switch, 36...
...Drive device, 37...Motor, 38...
...Rotary encoder, 39...Tacho generator, 4o...Flexible transmitter,
41...Print head carrier, 42...
・Linear sensor, 43...Position signal generator,
44... Speed signal generator, 45...
State quantity detection device. Agent: Patent Attorney Shinkyo Uchihara /l! I

Claims (1)

[Claims] In a printer in which a motor and a print head carrier are connected by a flexible transmitter, the motor, flexible transmitter, and print head are connected until the print head carrier changes from a stopped state to a constant speed state and from a constant speed state to a stopped state. The motor is driven according to the optimum drive profile of the speed of the motor that minimizes the energy of the driving force that changes the state in a given time with respect to the physical model of the drive system consisting of the carrier, and the print head carrier is kept constant. When the drive system is in a speed state, an optimal feedback gain is determined based on an optimal regulator law so that the printing impact by the printing hammer does not affect the movement of the print head carrier for the model of the drive system, and the state is fed back to control the speed of the drive system. A printer print head movement control system featuring: