Wheel Speed Sensor Latency Compensation
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Solution Overview
Problem
Vehicle systems face delays in wheel speed sensor signal processing due to measurement and communication latency, which can impact the effectiveness of systems relying on precise wheel speed data, such as wheel slip mitigation, leading to delayed reactions to changes in road surface conditions.
Innovation Solution
A wheel speed system that includes a wheel speed sensor, a wheel speed module, and a control module, which generates pulses based on wheel rotation teeth, compensates for latency by calculating a present compensated wheel speed using previous measured speeds, measurement latency, and communication latency, while ensuring stability and convergence to actual wheel speed through constraints on change limits and direction alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If wheel speed sensor data is processed using conventional methods, then the system structure is simple, but the reaction time is delayed due to measurement and communication latency
Solution Approach 1:
The patent applies preliminary action by calculating compensated wheel speed values in advance using the formula: compensated_speed = 2*current_measured_speed - previous_compensated_speed. This compensation calculation is performed proactively before the latency issue affects control decisions, allowing the system to predict current wheel speed based on measured data from previous time intervals. The wheel speed module continuously updates compensated speed values based on incoming sensor data, ensuring that up-to-date speed information is available for immediate control actions without waiting for raw sensor data to naturally become current.
2Measurement precision
If wheel speed data is used directly from sensors, then the processing is fast, but the data accuracy is reduced due to latency effects
Solution Approach 1:
The patent implements feedback by continuously comparing measured wheel speed with previously calculated compensated wheel speed values. The wheel speed module uses the feedback loop where the output of the compensation calculation (compensated speed) becomes the reference for the next calculation cycle. This creates a self-correcting system where the compensated speed adapts to actual wheel conditions while filtering out latency-induced errors. The feedback mechanism ensures that accuracy improvements are maintained over time without requiring re-calibration or additional sensors.
Data Source
AI summary
A wheel speed sensor is configured to generate pulses based on teeth that rotate with a wheel passing the wheel speed sensor. A wheel speed module is configured to receive first and second pulses, retrieve from memory a previous compensated wheel speed determined for the second time, determine a measured wheel speed at the first time and a previous measured wheel speed at the second time based on the first and second pulses, and determine a present compensated wheel speed for the first time based on (a) the measured wheel speed at the first time, (b) the previous compensated wheel speed for the second time and (c) a measurement latency of the wheel speed sensor. A control module is configured to actuate an actuator of the vehicle based on the present compensated wheel speed.