Stepping Motor Microstep Control for Accurate Servo Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing technologies face challenges in accurately performing servo control of stepping motors used in optical-disk playback apparatuses, particularly when the microstep division number is large, as the reduced impact of drive signal changes on the rotor leads to slow rotation and significant displacement of the intended rotation angle.
Innovation Solution
A disk playback apparatus with a drive control unit that temporarily returns the drive signal to its previous value and increases the change in the drive signal until the stepping motor rotates, applying a greater force to overcome the load and ensuring accurate servo control by incrementally increasing the rotation angle in microstep increments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the microstep division number is increased to reduce the impact on the rotor, then the smoothness of rotation is improved, but the stepping motor fails to rotate or rotates slowly in response to drive signal changes
Solution Approach 1:
The patent applies dynamics by making the drive signal change amount variable rather than fixed. The control unit dynamically adjusts the drive signal change amount based on whether the stepping motor rotated in the previous microstep operation. When rotation occurs, a standard change amount is used; when rotation fails, a larger change amount is applied, enabling the system to adapt its behavior based on real-time feedback while maintaining smooth microstep operation under normal conditions
Solution Approach 2:
The patent changes the parameter of drive signal change amount from a fixed value to a variable value that depends on rotation status. By modifying this parameter dynamically - using a first change amount for successful rotations and a second, larger change amount for failed rotations - the system resolves the contradiction between maintaining smooth microstep rotation and ensuring reliable motor response
2Reliability
If the drive signal value is gradually increased by a predetermined value until the stepping motor rotates, then the motor can be started, but a large amount of time is required and the rotation angle displacement becomes significantly larger than desired
Solution Approach 1:
The patent applies partial or excessive action by using a larger-than-normal drive signal change amount (excessive action) when the stepping motor fails to rotate. Instead of continuously applying small incremental changes that take time, the system temporarily applies a larger change amount to ensure rotation occurs, then returns to normal microstep operation. This resolves the contradiction by using excessive action only when necessary rather than continuously
3Speed
If the predetermined drive signal value is sufficiently increased to quickly rotate the stepping motor, then the rotation speed is improved, but the amount of difference between the change in rotation angle and the desired change in rotation angle always becomes large
Solution Approach 1:
The patent applies dynamics by making the drive signal change amount adaptive rather than fixed. The system dynamically switches between a standard change amount (for normal operation) and a larger change amount (when rotation fails). This dynamic adjustment allows the system to achieve quick rotation when needed while maintaining high precision during normal microstep operation, resolving the contradiction between speed and precision
Solution Approach 2:
The patent applies periodic action through the repeated cycle of attempting microstep rotation, detecting whether rotation occurred, and adjusting the drive signal change amount accordingly. This periodic feedback and adjustment mechanism allows the system to maintain precision during normal operation while periodically applying larger signal changes when rotation failures occur, balancing speed and accuracy requirements
Data Source
AI summary
When the magnitude of a traverse signal exceeds a predetermined level, the value of a microstep drive signal is changed by one microstep angle so that the rotation angle of the stepping motor changes in a rotation direction in which the magnitude of the traverse signal decreases. A determination is made as to whether or not the magnitude of the traverse signal becomes a predetermined level or less. When the magnitude of the traverse signal does not become the predetermined level or less, the magnitude of the microstep drive signal is returned to the pre-change value and the value of the microstep drive signal is incremented by an additional microstep angle so that the rotation angle of the stepping motor changes in a rotation direction in which the magnitude of the traverse signal decreases.