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Acceleration Compensation System for Low-Cost Voltage-Driven Motor Control System

IP.com Disclosure Number: IPCOM000062031D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Cavill, BR: AUTHOR [+2]

Abstract

A technique is described whereby an acceleration compensation motor control system, as used in matrix print head motor controls, provides for the automatic correcting of acceleration (deceleration) of a drive motor, so as to obtain the desired stopping time and distance of the print head operation. Although this technique is centered about print head applications, the concept is applicable to other motor control systems which require acceleration controls. The technique permits correction of open-loop acceleration so as to insure a fixed repeatable turnaround time and thereby a consistent repeatable stopping distance for any desired motor speed.

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Acceleration Compensation System for Low-Cost Voltage-Driven Motor Control System

A technique is described whereby an acceleration compensation motor control system, as used in matrix print head motor controls, provides for the automatic correcting of acceleration (deceleration) of a drive motor, so as to obtain the desired stopping time and distance of the print head operation. Although this technique is centered about print head applications, the concept is applicable to other motor control systems which require acceleration controls. The technique permits correction of open-loop acceleration so as to insure a fixed repeatable turnaround time and thereby a consistent repeatable stopping distance for any desired motor speed. Turnaround time is generally defined as the time required for the motor to go from a steady-state velocity in one direction to a steady- state velocity in the other direction without the motor actually stopping at a zero velocity. In order to obtain optimum performance, the turnaround time should be constant for any given steady-state speed of the motor. The acceleration correction motor control system provides this constant turnaround time through the use of an algorithm which provides the ability to change the rate at which the voltage at the motor changes on a line by line basis. A typical velocity versus time curve, as shown in Fig. 1, illustrates the turnaround time (TAT) as the motor changes direction. The voltage versus time curve, as shown in Fig. 2, illustrates how the change in velocity is produced by a change in voltage applied to the motor. The speed at which the motor will run is controlled by the steady-state voltage values V1 and V2 (V1 voltage is applied to run the motor in one direction and V2 voltage is applied to run the motor in the opposite direction). Because each speed that the machine runs is compensated, the steady-state velocity drive values V1 and V2 corresponding to velocities VEL 1 and VEL 2 will change as the compensation occurs. In order to calculate the effects of changes in V1 and V2 and to permit correction on each line, the following voltage ramp slope equation applies:

(Image Omitted)

The slope is calculated once per line and will change as the voltage values V1 and V2 change. A typical print head could conceivably operate at its highest velocity of 40 inches/sec with a turnaround time of 133 msec. The desired turnaround time (TAT) for any steady-state velocity (VEL) is expressed in equation:

(Image Omitted)

where VEL is expressed in inches/sec. A microprocessor exp...