Rail Axle Weight Estimation Using Wheel Slip and Traction Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing technologies fail to accurately determine the distribution of a rail vehicle's weight over its axles, leading to suboptimal acceleration and braking performance and a risk of wheel slippage.
Innovation Solution
A controller estimates axle weights by obtaining power and speed signals, applying traction or brake forces to wheel axles, and determining friction coefficients to distribute the overall weight accurately across axles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lowest axle weight is used to determine maximum traction/brake force, then wheel slippage is avoided, but acceleration/braking performance becomes suboptimal
Solution Approach 1:
The patent segments the total vehicle weight into individual axle weights by analyzing the dynamic response of each axle separately. By applying traction/brake forces to individual axles and measuring their specific acceleration responses, the system determines the weight carried by each axle independently, enabling optimized force distribution across all axles.
Solution Approach 2:
The patent applies different traction/brake forces to different axles based on their individual weight characteristics. Each axle receives a force adapted to its specific load condition, allowing heavily loaded axles to contribute more to acceleration/braking while lightly loaded axles operate within their slippage limits, optimizing overall performance.
2Productivity
If individual axle weights are accurately determined, then acceleration/braking performance is optimized, but system complexity increases
Solution Approach 1:
The system uses the rail vehicle's own drive units and existing acceleration sensors to determine axle weights. The drive units apply forces that serve dual purposes: propulsion and weight measurement. The acceleration sensors, already present for other control functions, are utilized to measure the dynamic response for weight determination, eliminating the need for separate measurement systems.
Solution Approach 2:
The system continuously monitors the acceleration response of each axle to applied traction/brake forces and uses this feedback to calculate individual axle weights. This real-time feedback mechanism enables dynamic adaptation of control parameters based on actual load conditions without requiring complex pre-calibration or manual input.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise axle weight estimation, allowing for optimized acceleration and braking without slippage, and adaptive control in response to load changes.
Implementation Method 1
Each drive unit (101, 102, 103) is configured to apply a respective traction force to each wheel axle (131, 132, 133) in a driving subset of the wheel axles (131, 132, 133, 134) so as to cause acceleration of the rail vehicle (100)
Implementation Method 2
determine a parameter that reflects a friction coefficient between a pair of wheels on the specific wheel axle and a pair of rails upon which the rail vehicle travels
Data Source
AI summary
An overall weight (mtot) of a rail vehicle (100) is estimated by obtaining a power signal (Pm) indicating an amount of power produced by a set of drive units (101, 102, 103) to accelerate the rail vehicle (100) between first and second speeds (v1; v2). Then, the following steps are executed: (a) obtaining wheel speed signals indicating respective rotational speeds (ω1, ω2, ω3) of the wheel axles in the driving subset of the wheel axles (131, 132, 133); (b) producing an acceleration control signal (A1) to a specific drive unit (101) in the set of drive units such that this drive unit applies a gradually increasing traction force to a specific wheel axle (131) of the wheel axles in the driving subset of the wheel axles (131, 132, 133); (c) repeatedly determining, during production of the acceleration control signal (A1), an absolute difference (|ω1−ωa|) between the rotational speed of the specific wheel axle (131) and an average rotational speed (ωa) of the wheel axles (132, 133) in the driving subset of the wheel axles except the specific wheel axle; and in response to the absolute difference (|ω1−ωa|) exceeding a threshold value; (d) determining a parameter (μm) reflecting a friction coefficient (μe) between a pair of wheels (121a, 121b) on the specific wheel axle (131) and a pair of rails (191, 192) upon which the rail vehicle (100) travels. Steps (a) to (c) are repeated for each of the wheel axles in the driving subset of the wheel axles, and based thereon, a respective fraction (m1, m2, m3) of the overall weight (mtot) carried by each of wheel axles in the driving subset of the wheel axles (131, 132, 133) is estimated.