Stepper Motor Current Control for Sensor-Lite Micro-Step Positioning
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Solution Overview
Problem
Existing stepping motor control systems face challenges in achieving quick and precise movement and positioning, particularly in applications requiring high torque utilization efficiency and robustness against external disturbances, due to limitations in torque control and the need for high-precision rotor position detectors.
Innovation Solution
A stepping motor control device that employs micro-step driving with adjustable operation modes, utilizing closed-loop control in the adjustment mode to generate control data for acceleration and deceleration operations, and open-loop control in the use mode to reproduce the winding current, allowing for maximum torque utilization without relying on high-precision rotor position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If closed-loop control with rotor position detector is used to achieve maximum torque acceleration and deceleration, then positioning speed and accuracy are improved, but device complexity and cost increase due to requiring high-precision rotor position detectors
Solution Approach 1:
The patent extracts the rotor position detector from the control system by using open-loop control with pre-stored control data, eliminating the need for feedback from position sensors while maintaining positioning performance
Solution Approach 2:
The patent performs preliminary action by pre-storing optimal control data (winding current patterns) that were originally obtained through closed-loop control, allowing the system to execute these pre-determined control sequences without real-time feedback, thus achieving maximum torque acceleration and deceleration without requiring rotor position detectors
2Ease of operation
If full-step driving is used to reduce device complexity, then ease of operation is improved, but productivity decreases due to longer positioning time and oscillation
Solution Approach 1:
The patent changes the control parameters by using micro-step driving instead of full-step driving, dividing the excitation phases into finer increments which enables smoother acceleration and deceleration profiles, reducing oscillation and positioning time while maintaining ease of operation through stored control data
3Productivity
If micro-step driving with maximum torque control is used to improve positioning capability, then productivity is improved, but reliability decreases due to sensitivity to external disturbances and load variations
Solution Approach 1:
The patent incorporates feedback mechanisms through the storage and reproduction of control data that was originally obtained through closed-loop control with feedback, allowing the system to maintain reliability under varying conditions by using pre-optimized control patterns that account for load and disturbance variations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient and precise movement and positioning with maximum torque utilization, reducing oscillation and improving robustness against external disturbances, while eliminating the need for expensive and large high-precision rotor position detectors.
Implementation Method 1
The stepping motor is generally configured to rotate a predetermined angle every time when its excitation phase is switched over
Data Source
AI summary
A stepping motor control device is provided, which controls a stepping motor including a rotor position detector by micro-step driving. The control device has a plurality of operation modes including an adjustment mode and a use mode. In the adjustment mode, the control device generates control data for a closed loop control for controlling the winding current of the stepping motor based on the detection value of the rotor position detector, and performs a stepping motor acceleration operation and a stepping motor deceleration operation according to the control data. In the use mode, the control device performs the stepping motor acceleration operation and the stepping motor deceleration operation so that a winding current observed in the adjustment mode is reproduced by an open loop control for controlling the winding current of the stepping motor based on the control data generated in the adjustment mode.