Vehicle Speed Monitoring via Predicted Dynamics
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Solution Overview
Problem
Current Positive Vehicle Control (PVC) systems face inaccuracies in speed determination due to wheel slip or slide events, particularly in areas with poor navigation satellite coverage, leading to unsafe vehicle operation as they rely on last recorded speed until satellite and tachometer speeds converge, causing prolonged inaccurate braking curve calculations.
Innovation Solution
A monitoring system that includes sensors and processors to determine a predicted vehicle speed based on forces acting on the vehicle, such as route grade and resistive forces, allowing for accurate braking calculations during wheel slip or slide events by using calculated speed until the tachometer and satellite speeds match.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the PVC system uses wheel tachometer speed for monitoring, then speed data is continuously available, but wheel slip or slide events cause inaccurate speed determination
Solution Approach 1:
The patent introduces an intermediary algorithm that processes tachometer readings to detect wheel slip events. This algorithm acts as a mediator between the raw tachometer data and the speed used for PVC calculations, filtering out inaccurate readings caused by wheel slip while maintaining continuous speed availability for the monitoring system.
Solution Approach 2:
The system implements feedback by continuously monitoring tachometer readings and comparing them against expected speed ranges and acceleration rates. When anomalies indicating wheel slip are detected, the system adjusts its speed determination accordingly, creating a closed-loop feedback mechanism that maintains accuracy despite tachometer errors.
2Measurement precision
If the PVC system waits for satellite and tachometer speeds to converge after wheel slip, then accurate speed can be restored, but vehicle operation is delayed for up to ten seconds
Solution Approach 1:
The patent applies preliminary action by detecting wheel slip events in real-time and immediately switching to alternative speed determination methods before the satellite and tachometer speeds can converge. This proactive approach eliminates the waiting period by pre-establishing contingency procedures for when tachometer accuracy is compromised.
Solution Approach 2:
The system dynamically switches between different speed determination methods based on the detected operating conditions. During normal operation, it uses tachometer readings; during wheel slip events, it transitions to using satellite-derived speeds or calculated speeds based on train dynamics, creating a dynamic adaptation that maintains accuracy without time loss.
3Ease of operation
If the PVC system uses last recorded tachometer speed during wheel slip, then braking curves can be calculated, but the speed information becomes increasingly inaccurate over time
Solution Approach 1:
The patent introduces an intermediary algorithm that processes tachometer readings to detect wheel slip events. This algorithm acts as a mediator between the raw tachometer data and the speed used for PVC calculations, filtering out inaccurate readings caused by wheel slip while maintaining continuous speed availability for the monitoring system.
4Measurement precision
If the PVC system relies on navigation satellite system for speed validation, then wheel slip can be detected, but speed determination fails in areas with poor satellite coverage
Solution Approach 1:
The patent implements multi-functionality by creating a universal speed determination system that can operate in multiple modes: satellite-aided mode for normal operation, and autonomous mode using train dynamics calculations when satellite coverage is unavailable. This universal approach ensures reliable speed determination regardless of satellite availability while maintaining wheel slip detection capability.
Solution Approach 2:
The system changes operational parameters based on satellite availability. When satellite coverage is poor or unavailable, it transitions from satellite-dependent speed validation to using alternative parameters such as train mass, gradient, resistance forces, and motor/brake commands to calculate speed, thereby maintaining reliability across different operating environments.
Data Source
AI summary
A monitoring system includes a sensor that may output a sensed moving speed of a vehicle system. The monitoring system may also include one or more processors in communication with the sensor. The one or more processors may calculate a predicted speed of the vehicle system based on one or more forces acting on the vehicle system, and compare the predicted speed with the sensed moving speed. The one or more processors may also control movement of the vehicle system based on comparing the predicted speed with the sensed moving speed.