Electrodynamic Brake Slip Control for Changing Wheel-Rail Adhesion
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Solution Overview
Problem
The existing anti-skid systems for electrodynamic brakes in rail vehicles cannot effectively adapt to dynamic changes in wheel/rail contact conditions, leading to suboptimal adhesion utilization and prolonged braking distances due to fixed target slip values that do not account for varying wheel/rail contact conditions.
Innovation Solution
A method that dynamically adjusts the target slip for the electrodynamic brake by varying the second target slip within a predetermined range, defined by upper and lower limit values proportional to the rail vehicle's speed, allowing for increased adhesion utilization and shorter braking distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed target slip value is used for the electrodynamic brake, then the control system is simple and stable, but the adhesion utilization is suboptimal and braking distances are prolonged due to inability to adapt to dynamic wheel/rail contact conditions
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed target slip value to a dynamically adjustable target slip value that adapts to changing wheel/rail contact conditions. The control system continuously monitors actual slip and adjusts the target slip value within a predetermined range, enabling the electrodynamic brake to respond to dynamic adhesion variations while maintaining controlled complexity through structured adjustment rules.
Solution Approach 2:
The patent implements parameter changes by modifying the target slip value parameter based on detected wheel/rail contact conditions. The control unit adjusts the target slip value within a predetermined range according to the difference between actual and target slip, thereby optimizing adhesion utilization without requiring complete system redesign.
2Productivity
If the target slip is dynamically adjusted within a range, then the adhesion utilization is optimized and braking distance is shortened, but the control system complexity increases
Solution Approach 1:
The patent optimizes braking efficiency by dynamically changing the target slip value parameter within a predetermined range. The control algorithm adjusts this parameter based on the difference between actual and target slip, enabling adaptive optimization of adhesion utilization while maintaining manageable complexity through bounded adjustment ranges and systematic control logic.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the actual slip value and comparing it with the target slip value. The control unit uses this feedback information to adjust the target slip value dynamically, creating a closed-loop control system that optimizes braking performance while maintaining controlled complexity through structured feedback processing.
3Force
If the target slip value is increased to utilize maximum adhesion, then the braking force is improved, but the risk of wheel slip and flat spot formation increases
Solution Approach 1:
The patent applies dynamics by making the target slip value adjustable within a predetermined range rather than fixed. This dynamic adjustment capability allows the system to optimize braking force by increasing target slip when adhesion conditions permit, while simultaneously maintaining wheel slip protection by constraining adjustments within safe boundaries and responding to actual slip conditions in real-time.
Solution Approach 2:
The patent implements parameter changes by modifying the target slip value within a predetermined range to optimize the balance between braking force and wheel slip protection. The control system adjusts this parameter based on the difference between actual and target slip, enabling increased braking force utilization while maintaining reliability through bounded parameter adjustment and continuous monitoring.
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
This approach enhances adhesion utilization by adjusting the braking torque in real-time, ensuring the actual slip aligns with the adhesion maximum, thereby shortening the braking process and improving braking efficiency under varying conditions.
Implementation Method 1
an electric drive motor (AM) driving the wheelset (RS)
Implementation Method 2
The force transmission between wheel and rail is described by the so-called friction-slip function
Data Source
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AI summary
The inventive method for controlling an electrodynamic brake of a rail vehicle, wherein the electrodynamic brake comprises at least one wheelset, an electric drive motor driving the wheelset, a power converter controlling the drive motor, and a control device controlling the power converter, comprises at least the steps of controlling the power converter depending on a predetermined first target slip for the wheelset, wherein the first target slip is defined as dependent on a speed of the rail vehicle, determining an actual slip of the wheelset, and comparing the determined actual slip with a criterion dependent on the predetermined first target slip, and is characterized by the further step of controlling, depending on a result of the comparison, the power converter depending on a second target slip, wherein the second target slip is varied over time within a predetermined target slip range.wherein the target slip range is defined by upper and lower limits for the target slip and wherein the upper and lower limits are each defined depending on the speed of the rail vehicle.