Regenerative Braking Control via Safety Flag Filtering
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Solution Overview
Problem
Regenerative braking in vehicles can cause wheel slippage or locking, especially on precarious road conditions, due to its limited application to drive wheels and high risk of instability, necessitating a safer and cost-effective control method.
Innovation Solution
A method for controlling regenerative braking that switches to a second calculation mode after a certain number of active safety system activations, setting the regenerative braking setpoint to zero, using a counter incremented by persistent active safety system flag signals and filtered to avoid short-term activations, and considering master cylinder pressure to differentiate between voluntary and involuntary braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is activated to recover kinetic energy and recharge batteries, then energy efficiency is improved, but wheel slippage or locking occurs on precarious road conditions
Solution Approach 1:
The control device continuously monitors flag signals from active safety systems (ABS, ESC, ASR, AYC) and uses this feedback to dynamically adjust regenerative braking activation. When regulation flags are detected, the system reduces or prohibits regenerative braking, creating a closed-loop control that adapts to real-time road conditions and prevents wheel slippage while maximizing energy recovery during safe conditions
Solution Approach 2:
The system dynamically switches between different calculation modes for regenerative braking setpoints based on road conditions. In normal conditions, full regenerative braking is permitted; when regulation flags indicate precarious grip, the system transitions to restricted or prohibited modes, making the braking behavior adaptive rather than static
2Reliability
If complex stability indicators are calculated from oversteer correction, understeer correction and deceleration setpoints to improve safety, then wheel slippage prevention is improved, but system complexity and cost increase
Solution Approach 1:
The invention extracts and utilizes existing flag signals already generated by active safety systems (ABS, ESC, ASR, AYC) rather than implementing a complete stability indicator calculation system. By taking out and repurposing these existing regulatory flags as inputs to the regenerative braking control, the system achieves safety improvement without the computational complexity and cost of developing and maintaining a full stability indicator calculation system
Solution Approach 2:
The control device uses multi-functional flag signals from existing active safety systems for dual purposes: their original safety functions and as inputs for regenerative braking control. This universal use of existing signals eliminates the need for separate stability calculation systems, reducing overall system complexity while maintaining safety
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 safety by preventing regenerative braking when grip conditions are precarious, reducing the risk of wheel slippage or locking, while being more cost-effective than complex stability indicators.
Implementation Method 1
On a vehicle equipped with at least one electric traction or propulsion motor, it is possible, under certain conditions, to use the electric motor as a generator and thus to obtain an electric braking means.
Data Source
Figure 1~2
AI summary
A device (10) for controlling regenerative braking in a vehicle provided with a first regenerative braking means, and a second braking means, and designed to generate a regenerative braking setpoint (C el ) on the basis of a braking request signal originating from a driver pedal of the vehicle, the device comprising: reception means for receiving a flag signal (flag_reg) from an active security system of the vehicle, and processing means arranged in such a way as to increase a counter value (Count) when the received flag signal changes value to assume a value corresponding to an activation of a regulation by the active security system, and to generate a control signal (S), if the counter reaches a threshold, in order to end the generation of the regenerative braking setpoint.