Motor Control System for Belt-Driven Scanning Mechanisms
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Solution Overview
Problem
Existing motor control techniques for recording and image reading apparatuses fail to effectively eliminate speed fluctuations caused by cogging torque, particularly due to belt elongation and contraction during acceleration and deceleration, which affects the precision of the scanning mechanism.
Innovation Solution
A control system that generates a periodic signal with adjustable amplitude and phase to counteract torque ripple, using feedback and feedforward control mechanisms to synchronize motor rotation with belt elongation, thereby stabilizing the scanning speed by adjusting the signal period based on belt length changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feedback control and feed forward control are used to control motor speed, then speed control capability is improved, but speed fluctuations caused by cogging torque cannot be eliminated
Solution Approach 1:
The invention applies periodic action by generating a periodic compensation signal that matches the cogging torque period. This signal is added to the drive signal to counteract the periodic speed fluctuations caused by cogging torque, thereby stabilizing the motor speed while maintaining the feedback and feed forward control capabilities.
2Manufacturing precision
If belt elongation and contraction are considered in speed control, then acceleration and deceleration precision is improved, but speed changes caused by cogging remain unaffected
Solution Approach 1:
The invention merges multiple control strategies by combining feedback control, feed forward control, and periodic compensation control into a unified control system. This integration allows the system to simultaneously address belt elongation/contraction effects and cogging torque effects, achieving both acceleration precision and speed consistency.
3Reliability
If a periodic signal is generated to reduce torque ripple, then speed fluctuation is reduced, but the signal period must be adjusted based on belt length changes
Solution Approach 1:
The invention applies dynamics by making the periodic signal parameters (amplitude and phase) adjustable and adaptive. The control system dynamically adjusts these parameters based on detected belt length changes, allowing the periodic compensation signal to remain effective despite variations in belt elongation during operation.
4Measurement precision
If feedback control is used based on speed difference, then speed accuracy is improved, but it cannot compensate for periodic cogging torque effects
Solution Approach 1:
The invention applies preliminary action by adding a periodic compensation signal in advance to counteract the expected cogging torque effects. This proactive compensation occurs before the speed fluctuations can significantly impact performance, working in conjunction with the feedback control that corrects based on actual speed differences.
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
An apparatus includes a driven object (2), a motor (7) configured to function as a driving source of the driven object (2), scanning means configured to cause the driven object to move, and include a first pulley (8) to which the motor (7) is connected, a second pulley (9) disposed opposing to the first pulley (8), and a member (6) stretched around the first pulley (8) and the second pulley (9), acquisition means (13) configured to acquire position information of the driven object, and signal generation means (110) configured to generate a periodic signal for controlling driving of the motor (7) based on the position information acquired by the acquisition means (13), wherein the signal generation means (110) increases a period of the signal to be generated, as a length of the member to which a pulling force is applied becomes shorter.