Wheel Speed Replacement Control Under Slip and Slide
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Solution Overview
Problem
Existing vehicle speed measurement systems, particularly in autonomous and rail vehicles, are prone to inaccuracies due to wheel slip or slide events, leading to undesirable situations such as collisions or non-compliance with speed restrictions.
Innovation Solution
A vehicle control system that includes an onboard controller to detect unreliable rotational speeds by comparing them to previous measurements and using predictive models to estimate or calculate replacement speeds, ensuring accurate vehicle speed calculation and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tachometer output is used to measure wheel rotational speeds, then vehicle speed can be calculated, but wheel slip or slide events cause inaccurate speed measurements
Solution Approach 1:
The patent introduces an intermediary computational process that mediates between the tachometer output and the final speed calculation. The controller compares the measured rotational speed with a predicted rotational speed (derived from other reliable sources or historical data) and uses this comparison to detect and correct errors caused by wheel slip or slide, thereby improving measurement reliability without sacrificing measurement capability
Solution Approach 2:
The system implements feedback by continuously monitoring the discrepancy between measured and predicted rotational speeds. When the measured speed deviates from the predicted speed beyond a threshold, the system detects wheel slip/slide conditions and adjusts the speed calculation accordingly, creating a closed-loop control that maintains accuracy despite sensor errors
2Reliability
If multiple speed sources are required by PTC systems, then movement compliance can be monitored, but inconsistent speeds from tachometer output may cause system deactivation
Solution Approach 1:
The patent applies preliminary action by predicting what the rotational speed should be before actually using it for control decisions. The controller pre-calculates an expected rotational speed based on reliable data sources and compares it with the tachometer measurement in advance, allowing the system to proactively identify and correct inconsistencies before they cause PTC system deactivation
Data Source
AI summary
A controller may be configured to receive one or more measured rotational speeds of a wheel of a vehicle. The controller may be configured to determine whether the one or more measured rotational speeds are unreliable relative to one or more previous rotational speeds of the wheel of the vehicle. The controller may be configured to calculate a replacement rotational speed of the wheel and use the replacement rotational speed of the wheel to control or restrict movement of the vehicle using or based on the replacement rotational speed in place of the one or more measured rotational speeds.