Adaptive Wheel Slip Control for Electric Vehicle Stability
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Solution Overview
Problem
Existing slip control systems in electric and hybrid vehicles often result in excessive control interventions during regenerative braking, leading to reduced driving stability and inefficient energy recovery, as they do not adapt to the vehicle's driving situation effectively.
Innovation Solution
A device that generates a control signal based on the steering angle to adjust the target slip value for wheel slip control, allowing for adaptive management of recuperation torque and maintaining driving stability without additional hardware, using existing control systems or a simple software update.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low target slip threshold is set to prevent wheel lock-up during recuperation, then wheel slip control is improved, but control interventions occur excessively even when not necessary, reducing driving stability
Solution Approach 1:
The patent applies dynamics by making the target slip threshold adaptive rather than fixed. The threshold dynamically adjusts based on the vehicle's operating state (acceleration, deceleration, steering angle) detected by sensors. This allows the system to maintain reliable wheel slip control while avoiding excessive interventions that would compromise driving stability, as the threshold automatically adapts to appropriate values for each driving situation.
Solution Approach 2:
The patent changes the parameter of target slip threshold from a constant value to a variable parameter that changes based on driving conditions. By monitoring acceleration, deceleration, and steering angle, the system modifies the threshold parameter to match the current operating state, preventing unnecessary control interventions while maintaining effective slip control when needed.
2Loss of energy
If regenerative braking torque is increased to maximize energy recovery, then energy efficiency is improved, but the braking torque may exceed the maximum torque transmissible via friction, leading to wheel lock-up
Solution Approach 1:
The patent implements feedback by continuously monitoring wheel slip, acceleration, deceleration, and steering angle through sensors. This feedback loop allows the system to adjust the regenerative braking torque in real-time, maximizing energy recovery while preventing wheel lock-up. The control unit uses the sensor data to modulate the recuperation torque, ensuring it remains within safe limits while optimizing energy capture.
Solution Approach 2:
The patent applies preliminary anti-action by proactively limiting the regenerative braking torque based on predicted wheel slip conditions. Before wheel lock-up can occur, the system uses the low target slip threshold to preemptively reduce the recuperation torque, preventing the harmful effect of wheel lock-up while still capturing maximum safe energy during deceleration.
3Stability of the object's composition
If additional sensors and control systems are added to improve slip control adaptability, then driving stability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a control system where existing sensors serve multiple functions. The steering angle sensor not only provides steering information but also helps determine wheel slip conditions and adjust the target threshold. The acceleration sensor serves both vehicle dynamics control and slip threshold adjustment purposes. This multi-functionality improves driving stability without adding dedicated components solely for slip control adaptation.
Solution Approach 2:
The system applies self-service by using already-available sensor data from the vehicle's existing systems to automatically adjust the slip control parameters. The control unit processes information from acceleration and steering sensors that are already present in modern vehicles, eliminating the need for additional specialized sensors. The system serves itself by leveraging existing infrastructure to achieve adaptive slip control.
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 reduces unnecessary control interventions, enhances cornering stability, and maximizes energy recovery by dynamically adjusting the target slip value based on the steering angle, ensuring optimal recuperation performance without complex additional systems.
Implementation Method 1
during regenerative braking or recuperation the captured kinetic energy is converted into electrical energy by a generator and stored as a charge in the vehicle's battery for later use
Implementation Method 2
The electrical energy recovered in electric vehicles or vehicles with partially electric drive through recuperation of kinetic energy when reducing speed creates a braking torque at the wheels or at a single wheel connected to the recuperation device
Data Source
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AI summary
A device (2) for generating a control signal (14) that influences the control of a wheel (16) of a motor vehicle comprises an input interface (4) for receiving a sensor signal (6) representing a steering angle (29) of the steered wheels (16) of the vehicle and a control unit (8) configured to provide a target slip value (10) based on the sensor signal (6), wherein the target slip value (10) represents a tolerable slip of the wheel (16). An output interface (12) is configured to output a control signal (14) that causes the change of an instantaneous target slip value of a wheel (16) slip control system to the target slip value.