Geared Motor Origin Detection Using Absolute Encoder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional geared motors require a significant amount of time to accurately determine the mechanical starting point of the output shaft during startup and other operations due to the need for extensive rotational movements, which are inefficient and prone to errors caused by backlash and torsion in the reduction gear.
Innovation Solution
The implementation of a geared motor with a motor encoder and an output-side absolute value encoder, along with a drive control circuit that computes the mechanical starting point based on the absolute rotational position of the output shaft, allowing for rapid and precise detection by rotating the motor shaft only 360 degrees, and incorporating error consideration zones to accurately calculate the number of rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor shaft is rotated multiple times (e.g., 50 rotations for 1:50 reduction gear) to return the output shaft to the origin position using conventional origin sensor methods, then the origin position can be detected, but a considerable amount of time is required and the process is inefficient
Solution Approach 1:
The patent replaces the conventional mechanical rotation-based origin detection method with an absolute value encoder that directly detects the absolute rotational position of the output shaft. This substitution eliminates the need for multiple rotational movements (50 rotations for 1:50 gear ratio) and allows the mechanical starting point to be detected within a single 360-degree rotation, dramatically reducing the time required while maintaining detection accuracy.
Solution Approach 2:
The patent introduces an absolute value encoder as an intermediary device mounted on the output shaft to directly detect its absolute rotational position. This intermediary provides precise position information to the drive control circuit, enabling the calculation of the mechanical starting point without requiring extensive rotational movements, thus resolving the time-consuming issue of conventional methods.
2Reliability
If the motor shaft is rotated by an amount equal to the reduction gear ratio (e.g., 50 times for 1:50 gear) to ensure complete coverage of the output shaft's rotational range, then the origin position can be found, but the process becomes complex and time-consuming
Solution Approach 1:
The patent replaces the complex mechanical rotation process with an electronic detection system using an absolute value encoder. The encoder directly provides absolute position information, allowing the drive control circuit to calculate the mechanical starting point through simple computational logic rather than executing complex multi-step rotational movements, thereby reducing process complexity while maintaining reliability.
Solution Approach 2:
The absolute value encoder预先 (in advance) detects the absolute rotational position of the output shaft, providing the drive control circuit with the necessary position information before origin return movement begins. This preliminary detection enables the system to calculate and return to the mechanical starting point efficiently without needing to perform extensive rotational searches, simplifying the overall process.
3Measurement precision
If the motor shaft is rotated multiple times to account for backlash and torsion in the reduction gear, then the origin position can be detected with good accuracy, but the detection process takes a considerable amount of time
Solution Approach 1:
The patent substitutes the mechanical rotation method with an absolute value encoder that directly measures the absolute rotational position of the output shaft. This electronic measurement system eliminates the need for multiple rotational movements required to compensate for backlash and torsion, achieving accurate mechanical starting point detection within a single 360-degree rotation, thus dramatically reducing detection time while maintaining or improving accuracy.
Solution Approach 2:
The absolute value encoder serves as an intermediary that directly detects the absolute rotational position of the output shaft, providing precise position information to the drive control circuit. This intermediary device eliminates the need for iterative rotational movements used to compensate for mechanical imperfections like backlash and torsion, enabling accurate and rapid detection of the mechanical starting point.
Data Source
AI summary
A motor encoder is mounted on a motor shaft of a geared motor 1, and the origin position is detected by using a Z-phase signal. An absolute value encoder with a precision that allows the number of motor rotations to be determined is mounted on an output shaft 4 of a reduction gear, and the absolute rotational position thereof is detected. When the first Z-phase signal generated in conjunction with the rotation of the motor shaft 2a is obtained at startup and at other times, the mechanical starting point at which the motor shaft and output shaft are both positioned at the origin can be calculated based on the absolute rotational position of the reduction-gear output shaft obtained from the output-side absolute value encoder. Since the mechanical starting point is obtained by rotating the motor shaft a single rotation at most, the time required to calculate the mechanical starting point is short in comparison with conventional examples, and extraneous rotational movements can be avoided.