Encoder Delay Compensation Filter for Accurate Angle Interpolation
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Solution Overview
Problem
Digital encoders used in manufacturing robots face inaccuracies in measuring the angle position of rotating objects due to propagation delay in signal processing, which existing solutions like dual-position sensor systems with feedback loops are unable to fully compensate for, especially at higher dynamic ranges.
Innovation Solution
A propagation delay compensation and interpolation filter system that includes low pass filters and differentiators to reduce noise and calculate speed and acceleration, allowing for accurate real-time angle position measurement by compensating for delays in digital signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dual-position sensor system with feedback loop is used to compensate propagation delay, then measurement precision is improved, but device complexity increases and stability deteriorates
Solution Approach 1:
The patent extracts the delay compensation function from a complex dual-sensor feedback system and implements it within a single sensor's signal processing chain. By taking out the compensation algorithm and integrating it into the existing sensor output processing, the system achieves delay compensation without adding duplicate sensors or complex feedback loops, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent introduces an intermediary computational layer that processes the sensor output signal to compensate for propagation delay. This intermediary processing stage calculates corrected position values by compensating for the known delay characteristics of the signal processing chain, acting as a mediator between the raw sensor data and the final position output, thereby improving accuracy without requiring additional physical sensors.
2Measurement precision
If feedback loop is used for delay compensation, then measurement precision is improved, but reliability deteriorates due to instability
Solution Approach 1:
The patent applies preliminary action by pre-calculating and applying delay compensation to the sensor signal before it enters the control loop. Instead of using a feedback mechanism that reacts to errors after they occur, the system proactively compensates for the known propagation delay in advance, eliminating the need for unstable feedback loops and improving system reliability while maintaining precision.
3Measurement precision
If dual-position sensor system is used, then measurement precision is improved, but ease of operation worsens
Solution Approach 1:
The patent makes the single sensor system multi-functional by integrating multiple capabilities into one component. The sensor not only measures position but also provides data for delay compensation calculations. This universal approach eliminates the need for separate dual-sensor systems, maintaining measurement precision while simplifying system operation and reducing the number of components that need to be managed.
Data Source
AI summary
Various embodiments provide a filter for propagation delay compensation and interpolation in encoder digital signal processing. The filter can include a first low pass filter configured to reduce noise of a digital input comprising a measured angular position; a first differentiator configured to receive a filtered digital input and to calculate a speed from a difference in time of the measured angular position and a previous angular position; a second low pass filter configured to reduce noise from the speed; a second differentiator configured to receive a filtered speed and to calculate acceleration using a difference in time of the filtered speed and a previous speed; a third low pass filter configured to reduce noise of the acceleration; and a delay compensator configured to receive the filtered digit input, the filtered speed, and a filtered acceleration, and to calculate a propagation delay compensated digital output.