Rail Vehicle Braking System Gradient Force Estimation
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Solution Overview
Problem
Rail vehicles face challenges in maintaining precise braking distances and forces, especially on gradients, due to the neglect of downhill force in existing braking systems, leading to variations in braking effectiveness and safety concerns.
Innovation Solution
A braking system that includes a braking force estimator to detect acceleration components and downhill force, using a setpoint generator, controller, and actuator to adjust braking forces based on vehicle longitudinal deceleration, running speed, and mass, with a braking force distributor to optimize individual braking forces across different brake types, and pilot control to improve control quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional braking systems are used without considering downhill force, then the braking system structure remains simple, but braking precision and safety deteriorate on gradients
Solution Approach 1:
The patent introduces a braking force estimator as an intermediary device that calculates the actual braking force by combining acceleration sensor data with modeled resistance forces (downhill force, air resistance, rolling resistance). This estimator acts as a mediator between the simple acceleration measurement and the complex multi-brake system, providing precise braking force information without requiring direct measurement of each brake's contribution or complex infrastructure.
Solution Approach 2:
The patent replaces direct mechanical measurement of braking force with a computational approach. Instead of using complex mechanical force sensors on each brake, the system uses acceleration sensors combined with mathematical models of resistance forces to estimate braking force. This substitution of mechanical measurement with computational estimation reduces device complexity while improving measurement precision.
2Reliability
If braking force is increased to compensate for downhill force on gradients, then braking distance is maintained, but braking force control precision deteriorates due to overcompensation
Solution Approach 1:
The patent implements feedback control by continuously comparing the estimated actual braking force with the desired braking force and adjusting brake actuation accordingly. The braking force estimator provides real-time feedback on the actual braking effect, allowing the control system to compensate for downhill force precisely without overcompensation. This closed-loop feedback ensures reliable braking distances while maintaining control precision through dynamic adjustment.
Solution Approach 2:
The patent dynamically changes braking parameters based on detected acceleration and calculated resistance forces. The system adjusts the braking force setpoint according to the downhill force calculation (which varies with gradient and speed) and modifies individual brake contributions based on their optimal operating ranges. This parameter adaptation allows precise braking force control on gradients while maintaining optimal performance of each brake type.
3Productivity
If multiple brake types are used with different operating ranges, then braking efficiency is improved, but braking force consistency deteriorates due to tolerances and imprecisions in each brake type
Solution Approach 1:
The patent dynamically adjusts the contribution of each brake type based on real-time operating conditions and estimated braking force feedback. The braking force distributor continuously optimizes the manipulation variables for each brake (friction brake, electrodynamic brake, electromagnetic rail brake, eddy current brake) according to their current operating state and optimal ranges. This dynamic optimization maintains braking efficiency while compensating for individual brake tolerances and imprecisions through continuous adaptation.
Solution Approach 2:
The braking force estimator provides continuous feedback on the actual braking force generated by the multi-brake system. This feedback allows the control system to detect and compensate for variations in braking force from individual brakes due to tolerances and imprecisions. By monitoring the actual effect and adjusting individual brake contributions, the system maintains consistent overall braking force while preserving the efficiency benefits of multiple brake types.
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
The system enhances braking precision and safety by adapting to gradients, reducing braking distances and maintaining specified decelerations, ensuring maximum traction utilization and improved control quality without requiring detailed knowledge of the brakes used.
Implementation Method 1
means for detecting acceleration components
Implementation Method 2
friction brake
Implementation Method 3
electrodynamic brake
Implementation Method 4
electromagnetic rail brake
Implementation Method 5
eddy current brake
Data Source
AI summary
A braking system for a rail vehicle includes a target value generator for the target value of the overall braking power, a controller for determining at least one manipulated variable value on the basis of the target value and at least one actuator which transmits the manipulated variable value to the at least one braking device. The system at least approximately determines acceleration components of the rail vehicle and determines the actual value of the total braking power from the acceleration components while taking the vehicle speed and the vehicle mass into consideration. The controller is designed to control the manipulated variable value such as to reduce the control deviation between the target value and the determined actual value.