DC Motor Position Control via Potentiometer and Surge Current
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Solution Overview
Problem
Existing motor control devices face challenges in accurately detecting the rotation state of DC motors due to variations in potentiometer resistance values and low surge current detection accuracy at lower rotation speeds, leading to instability in position control.
Innovation Solution
A motor control device that utilizes both absolute and relative position information, obtained through different methods, to set and correct the actual position of the output shaft, incorporating a potentiometer and surge current detection to enhance accuracy and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a potentiometer is used to detect the rotation state of the DC motor, then the rotation state can be detected, but the detection accuracy deteriorates due to variations in resistance value
Solution Approach 1:
The patent combines two different detection methods (potentiometer-based absolute position detection and surge current-based relative position detection) into a unified position detection system. The controller integrates both detection results to determine the rotor position, thereby compensating for the weaknesses of each individual method and achieving both reliability and precision in rotation state detection.
2Ease of manufacture
If surge current detection is used to detect the rotation state, then the detection method is simple, but the detection accuracy deteriorates at lower rotation speeds
Solution Approach 1:
The patent merges surge current detection with potentiometer-based detection to create a hybrid system. The controller selectively uses surge current detection results when they are reliable (at higher speeds) and switches to or combines with potentiometer-based results when surge current detection accuracy deteriorates (at lower speeds), thereby maintaining both system simplicity and detection accuracy across all operating conditions.
3Device complexity
If only one detection method is used, then the system is simple, but the position control accuracy deteriorates
Solution Approach 1:
The patent implements a multi-method detection system where the controller integrates results from both potentiometer-based absolute position detection and surge current-based relative position detection. This combination approach achieves high position control accuracy by compensating for the limitations of each individual method while maintaining reasonable system complexity through unified control logic.
Data Source
AI summary
A motor control device is a device for controlling a drive of a DC motor which is interlocked with an output shaft portion of an actuator. The motor control device includes: a relative position obtainer detecting current fluctuations when switching a connection between a commutator and a brush in the DC motor or when rotating the DC motor and obtaining relative position information of the output shaft portion; and an absolute position obtainer obtaining absolute position information of the output shaft portion using a potentiometer. The motor control device further includes: an actual position setter setting actual position information of the output shaft portion based on at least one of the absolute position information and the relative position information.