Controller Voltage Command Switching for Precision Stopping
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Solution Overview
Problem
Conventional control systems face challenges in precisely stopping an object at a target stop position due to overshoot issues when switching from velocity control to position control, leading to imprecise positioning and potential collisions or print quality degradation in image forming systems.
Innovation Solution
A control system that includes a motor, a moving apparatus, a detector, and a controller that inputs a first voltage command value based on velocity deviation until a predetermined time, then switches to a second voltage command value based on position deviation with an integral transfer function, setting an initial value for the integral element to enable precise position control and stop the object at the target position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching from velocity control to position control is executed during deceleration by passing over the control input, then the control mode transitions smoothly, but the object cannot be stopped precisely at the target stop position causing overshoot
Solution Approach 1:
The patent applies preliminary action by setting the initial value of the integral element in the position control to a specific value calculated from the velocity command value and acceleration at the switching point. This preliminary setup ensures that the position control can immediately continue the deceleration process without interruption, enabling precise stopping at the target position while maintaining smooth transition between control modes.
2Ease of operation
If the initial value of integral element is set to continue the voltage command value from velocity control, then control input is succeeded between modes, but the object cannot decelerate sufficiently after switching
Solution Approach 1:
The patent applies parameter changes by transforming the initial value of the integral element from a simple voltage command continuation to a specifically calculated value based on the relationship: initial integral value = (velocity command value × time constant) / acceleration. This parameter transformation enables the position control to achieve sufficient deceleration capability while maintaining control input continuity, resolving the contradiction between ease of operation and speed control.
Data Source
AI summary
There is provided a control system including: a motor, a moving apparatus, a detector, a driving circuit, and a controller. The controller executes: inputting, to the driving circuit, a first voltage command value up to a predetermined time; inputting, to the driving circuit, a second voltage command value since the predetermined time, and in accordance with a predetermined transfer function including an integral element; and setting an initial value of the integral element. The predetermined time is a time since the deceleration of the object has been started. When executing the switching from the first voltage command value to the second voltage command value, the controller sets a target position trajectory of the object up to the target stop position. Further, the controller sets the initial value of the integral element.