Rotation Angle Compensation Using Directional Error Patterns
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Solution Overview
Problem
Conventional rotation angle detection systems for machine tools face challenges in accurately compensating for tooth-to-tooth period errors due to varying error patterns based on detection conditions, such as rotation direction and temperature, which affects the precision of indexing and positioning.
Innovation Solution
A method that detects individual error patterns under different conditions, such as forward and backward rotation directions and varying temperatures, to precisely correct the command value for rotation angle, reducing the number of compensation points and memory required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a tooth-to-tooth period error pattern in an arbitrary tooth-to-tooth period is used for all tooth-to-tooth periods, then the number of compensation points is greatly reduced and memory capacity is reduced, but the error pattern varies depending on detection conditions such as rotation direction and temperature
Solution Approach 1:
The error pattern is segmented by detection conditions (rotation direction, temperature ranges). Multiple error patterns are stored in the storage unit, each corresponding to a specific condition. The selection unit selects the appropriate error pattern based on current detection conditions, allowing accurate compensation without requiring compensation points for every possible condition.
Solution Approach 2:
The system dynamically selects the appropriate error pattern based on real-time detection conditions. The selection unit determines which error pattern to use based on the current rotation direction and temperature, making the compensation system adaptive to varying conditions while maintaining a compact error pattern storage structure.
2Reliability
If multiple error patterns are stored for different detection conditions, then compensation accuracy is improved, but memory capacity increases
Solution Approach 1:
Different error patterns are stored for different local conditions (rotation directions, temperature ranges). Each error pattern is optimized for its specific condition range, providing locally accurate compensation. The storage unit maintains separate error patterns only for distinct conditions rather than storing continuous variations, reducing overall memory requirements.
Solution Approach 2:
The system stores error patterns for representative conditions rather than all possible conditions. By selecting key detection conditions (forward/reverse rotation, temperature ranges) and storing error patterns for these representative cases, the system achieves sufficient compensation accuracy without the excessive memory capacity that would be required to store error patterns for every possible condition combination.
3Device complexity
If conventional rotation angle positioning devices are used, then device complexity is low, but they cannot cope with tooth-to-tooth period error compensation
Solution Approach 1:
The error pattern storage unit and selection unit provide multi-functional capability. The same basic structure (storage unit + selection unit) handles multiple types of error compensation (rotation direction errors, temperature-induced errors) by storing different error patterns for different conditions. This universal approach enables precise compensation without requiring separate complex compensation mechanisms for each error type.
Solution Approach 2:
The system compensates for positioning errors by changing the parameter being corrected (command value for rotation angle) based on stored error patterns. Rather than modifying the physical detection device or its structure, the system adjusts the command parameter dynamically based on detected conditions and corresponding error patterns, achieving high positioning precision with minimal structural complexity.
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
This approach enhances the precision of indexing and positioning by adapting to varying error patterns, ensuring accurate rotation angle compensation regardless of detection conditions, thereby improving the overall precision of rotating shaft positioning.
Implementation Method 1
a magnetic detection device fixedly disposed at a position facing the teeth of the detection target gear and outputting a voltage signal according to its distance to the teeth
Data Source
AI summary
There is provided a method of compensating a command value for rotation angle capable of precisely compensating a command value for rotation angle even when conditions at detection differ to thereby make error patterns different in the case where a tooth-to-tooth period error pattern in an arbitrary tooth period is used for all the tooth periods to correct a command value for rotation angle. A forward direction tooth-to-tooth period error pattern being an error pattern of detected rotation angles at forward rotation and the actual rotation angles and a backward direction tooth-to-tooth period error pattern being an error pattern at backward rotation are found, and the command value for rotation angle is corrected based on the error pattern at the time of forward rotation, and the command value for rotation angle is corrected based on the error pattern at the time of backward rotation.