Rail Vehicle Speed Estimation Under Axle Slip Using Kalman Filtering
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Solution Overview
Problem
Existing methods for determining the speed of rail vehicles lack accuracy and are costly, particularly in estimating motion parameters with high precision.
Innovation Solution
An estimation device utilizing a Kalman filter, slip module, and evaluation module to determine vehicle speed, incorporating torque, vertical force, and wheel speed values, with a slip module adjusting wheel circumferential speed based on axle slippage, and an evaluation module refining estimates based on Kalman-estimated vehicle speed and slip values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to determine vehicle speed, then hardware costs and time costs are high, but measurement precision is insufficient
Solution Approach 1:
The patent replaces complex mechanical measurement systems with a computational approach using an extended Kalman filter that processes data from existing sensors (torque, vertical force, wheel speed) to estimate vehicle speed and motion parameters, thereby achieving high precision without additional expensive hardware
Solution Approach 2:
The patent introduces an extended Kalman filter as an intermediary computational system that processes measurements from existing sensors (torque values, vertical force values, wheel speed values) to produce accurate motion estimates, acting as a mediator between raw sensor data and the required motion parameters
2Measurement precision
If conventional methods are used to determine vehicle speed, then hardware costs and time costs are high, but measurement precision is insufficient
Solution Approach 1:
The extended Kalman filter continuously processes sensor data in real-time to provide continuous motion estimates, eliminating the need for periodic expensive measurements and reducing overall time costs while maintaining high precision throughout the measurement period
Solution Approach 2:
The patent performs preliminary computational processing of sensor data through the extended Kalman filter to predict and estimate motion parameters before actual measurement is needed, reducing the time required for accurate speed determination
3Ease of operation
If wheel circumferential speed is used directly during slippage, then calculation is simple, but measurement precision deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the extended Kalman filter continuously monitors wheel slippage conditions and adjusts the speed estimation approach accordingly, using feedback from torque and vertical force sensors to maintain accuracy even when wheel slippage occurs
Solution Approach 2:
The patent dynamically adapts the speed estimation method based on operating conditions, switching between using wheel circumferential speed during normal operation and relying on Kalman filter estimation during slippage conditions, making the system flexible and condition-dependent
Data Source
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AI summary
The invention relates, inter alia, to an estimating device (1) for determining a new estimated movement value (v_virt), which indicates the speed of a rail vehicle (200) having at least two axles, comprising: a Kalman filter (30), which is supplied on the input side with at least force moment values (m_p_i, m_e_i), vertical force values (Q_i), wheel size values (r_i) and wheel speed values (ω_i) and on the basis of these, as well as on the basis of a Kalman filtering, determines a Kalman estimated vehicle speed value (v_k); a slip module (40), which is supplied on the input side with the force moment values (m_p_i, m_e_i), the wheel size values (r_i), the wheel speed values (ω_i) and the respective previous estimated movement value (v_virt) of the estimating device (1), and determines a wheel circumferential speed value (v_umlauf) and a sliding indication, which indicates any sliding of the respective axle; and an evaluation module (50), which determines the new estimated movement value (v_virt) of the estimating device (1), on the basis of the Kalman estimated vehicle speed value (v_k), the wheel circumferential speed value (v_umlauf) and the sliding indications.