Rotary Encoder Calibration Using Angular Velocity Error Compensation
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Solution Overview
Problem
Rotary encoders in autonomous vehicles suffer from manufacturing inconsistencies such as eccentricity and tilt errors, leading to inaccurate sensor data, particularly in lidar systems, which affect the accuracy of autonomous vehicle navigation.
Innovation Solution
A sensor calibration mechanism that determines positioning errors of rotary encoders by analyzing angular velocity data to correct sensor data and improve accuracy, using methods to compensate for eccentricity and tilt errors without altering the encoder setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotary encoder is used for measuring angular position in autonomous vehicles, then navigation capability is enabled, but manufacturing inconsistencies such as eccentricity and tilt errors cause measurement precision to deteriorate
Solution Approach 1:
The patent transforms the rotary encoder's angular position measurements into angular velocity data through mathematical differentiation. This parameter transformation allows the system to exploit the periodic nature of encoder errors, enabling error characterization and compensation. By changing from position domain to velocity domain, the system can identify and correct manufacturing inconsistencies without physical modifications to the encoder.
2Manufacturing precision
If traditional calibration methods are used to correct encoder errors, then manufacturing precision requirements increase, but device complexity and calibration difficulty increase
Solution Approach 1:
The patent replaces complex mechanical calibration procedures with computational methods. Instead of physically adjusting or replacing the encoder to achieve higher manufacturing precision, the system uses signal processing and mathematical algorithms to characterize and compensate for errors. This substitution of mechanical calibration with computational correction reduces device complexity while maintaining or improving measurement accuracy.
3Measurement precision
If high-precision encoders are used to improve navigation accuracy, then measurement precision improves, but cost and device complexity increase
Solution Approach 1:
The patent enables the rotary encoder system to self-diagnose and self-correct its own manufacturing errors through mathematical analysis of its output signals. By processing its own measurement data through differentiation and error characterization algorithms, the system compensates for its imperfections without requiring external calibration equipment or higher-precision components, thereby reducing overall system complexity and cost.
Data Source
AI summary
The subject disclosure relates to techniques for determining a positioning error of a rotary encoder. A process of the disclosed technology can include steps of receiving measurement data including an angle and timestamp measured at each of a plurality of positions during a rotation of a rotary encoder, determining an angular velocity, at each of the plurality of positions, based on the corresponding measurement data, and determining a positioning error of the rotary encoder based on the angular velocity at each of the plurality of positions. Systems and machine-readable media are also provided.