Electric Wheel Slip Control for Stable Regenerative Braking
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Solution Overview
Problem
Existing systems for slip control in electrically driven vehicles struggle to maintain stability and steerability, particularly during braking, as they often require complex switching between electric drive and friction brake systems, and fail to effectively manage lateral forces, leading to instability and inefficient energy recovery.
Innovation Solution
A method and device that utilize torque control via an electric drive to manage wheel slip, determining instability through wheel slip comparison and adjusting the electric drive's torque to maintain a setpoint slip, allowing for efficient energy recuperation and stable lateral force transmission without relying on friction brakes, using existing sensors for accurate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ABS control mechanism acting solely via friction brake is used to prevent wheel locking, then wheel stability is maintained, but energy reclamation capability is lost and system complexity increases
Solution Approach 1:
The patent combines the electric drive system and friction brake system into a unified slip control mechanism. The electric drive is used for primary slip control during braking to enable energy reclamation, while the friction brake serves as a supplementary system. This merging allows the system to maintain wheel stability through coordinated control of both systems, eliminating the need to switch between separate ABS and regenerative braking modes.
Solution Approach 2:
The electric drive system is designed to perform multiple functions: it provides both propulsion and braking control. By enabling the electric drive to handle slip control during braking, the system eliminates the need for dedicated ABS friction brake intervention, allowing continuous energy reclamation while maintaining stability. The friction brake remains available as a backup or supplementary function.
2Reliability
If switching between electric drive and friction brake systems is implemented for slip control, then wheel locking is prevented, but system complexity increases and control responsiveness decreases
Solution Approach 1:
The patent integrates electric drive control and friction brake control into a single unified slip control algorithm. Instead of implementing separate ABS control and regenerative braking control that require switching between modes, the system uses a unified approach where the electric drive handles primary slip control and the friction brake provides supplementary support when needed. This eliminates complex switching logic and mode transitions.
3Ease of operation
If friction brake is used for ABS control, then wheel slip is controlled to maintain steerability, but energy recovery capability is reduced
Solution Approach 1:
The patent combines electric drive braking and friction brake functions into a unified system that prioritizes energy recovery. The electric drive performs the primary braking action to reclaim kinetic energy, while the friction brake is used only when additional braking force is needed beyond what the electric drive can provide. This merged approach maintains steerability through controlled slip while maximizing energy recovery.
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 ensures stable vehicle control with prioritized steerability and energy recovery, enabling effective transmission of both longitudinal and lateral forces, even without additional sensors, by controlling the electric drive's torque to prevent wheel instability and optimize energy feedback.
Implementation Method 1
torque control via an electric drive to manage wheel slip
Implementation Method 2
a friction brake is generally provided, which is configured in utility vehicles as a pneumatic brake
Implementation Method 3
the generator braking torque of the electric drive, that is, the recuperation, can thus result in a locking tendency of the wheel
Data Source
AI summary
The disclosure is directed to a method for slip control of a vehicle wheel driven via an electric drive. The method includes at least the following steps: driving the electric drive of the vehicle wheel using an actual drive torque in a torque control in a torque control step, determining a wheel speed and a wheel slip of the vehicle wheel and evaluating the wheel slip by way of an instability criterion as to whether an instability exists, upon recognizing an instability, direct or indirect transition in a slip control of the wheel slip to a setpoint slip by driving the electric drive, determining whether an end criterion for ending the slip control is satisfied; and, if the end criterion is satisfied, returning to the torque control in the torque control step.