Vehicle Brake Allocation Control for Stability and Energy Recuperation
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Solution Overview
Problem
Electric vehicles equipped with multiple braking devices face challenges in achieving a desired brake function without causing steer-by-brake, as each brake type has different operating capabilities and efficiencies, leading to stability issues and inefficient energy recuperation.
Innovation Solution
A method and system that determine the actuation priority of each braking device based on its capabilities and vehicle parameters, preferentially utilizing regenerative and non-frictional brakes to achieve a desired brake parameter, thereby optimizing brake distribution and extending vehicle range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative brakes are preferentially used to extend vehicle range through energy recuperation, then energy efficiency is improved, but braking devices may produce diverging braking torque causing steer-by-brake effects that worsen vehicle stability
Solution Approach 1:
The control method assigns different actuation priorities to different braking devices based on their local characteristics (regenerative efficiency, brake type, operating state). Regenerative brakes with higher efficiency receive higher priority, but the system locally adjusts the distribution of braking torque to each device to prevent steer-by-brake effects, thus maintaining vehicle stability while maximizing energy recuperation
Solution Approach 2:
The actuation priorities of braking devices are dynamically adjusted based on real-time operating conditions such as regeneration efficiency, vehicle speed, and brake capability. This dynamic prioritization allows the system to adaptively balance energy recuperation with vehicle stability requirements under varying operating conditions
2Force
If frictional brakes are used to provide sufficient braking force, then braking capability is improved, but brake device longevity deteriorates due to wear from friction
Solution Approach 1:
The system converts the harmful wear effect of frictional brakes into a beneficial outcome by using non-frictional brakes (regenerative and dissipational) as the primary braking means. Frictional brakes are reserved for situations where other brakes cannot provide sufficient braking force, thereby minimizing their wear and extending their service life while maintaining adequate braking capability
Solution Approach 2:
The control method changes the operating parameters of braking devices by assigning actuation priorities that favor non-frictional brakes. This parameter change in brake usage strategy reduces the cumulative wear on frictional brakes while maintaining the necessary braking force through the combined operation of multiple braking devices
3Force
If multiple braking devices are operated simultaneously to achieve desired brake function, then braking capability is improved, but system complexity increases due to coordination requirements
Solution Approach 1:
The control method segments the braking function by dividing the total desired braking force into portions allocated to different braking devices based on their actuation priorities. Each braking device operates independently according to its allocated portion, simplifying the control logic while maintaining the combined braking capability of the entire system
Solution Approach 2:
Each braking device determines its own contribution to the braking function based on its predetermined actuation priority and allocated portion of the desired brake function. This self-service approach reduces the complexity of inter-device coordination by allowing each device to autonomously regulate its braking output according to pre-established priorities
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 solution effectively allocates brake functions to preferred devices, enhancing vehicle stability, maintaining brake longevity, and improving electric vehicle range by prioritizing regenerative brakes for efficient energy recuperation.
Implementation Method 1
Regenerative brakes produce electric current from kinetic energy to recuperate, when braking, a portion of the energy from the motion of the vehicle
Implementation Method 2
This kind of brake may use resistive losses from eddy currents induced in moving parts to remove kinetic energy from the vehicle and dissipate it as heat
Data Source
AI summary
A method for controlling a multitude of braking devices of a vehicle to effect a desired brake function quantified as a desired brake parameter, wherein each of the braking devices is controllable by an actuation parameter to effect at least a portion of said desired brake function, comprising the steps: determine, for each braking device, a brake capability representing a maximum brake function achievable by the braking device; determine, for each braking device, an actuation priority, wherein the actuation priority is determined from at least one predetermined operating parameter of the braking device and/or the vehicle; in order from highest priority to lowest priority of the braking means, allocating, to each braking device, the actuation parameter, wherein the actuation parameter is chosen between the brake capability and the quantity of the desired brake parameter not yet allocated to other braking devices, whichever is lower. Further, a braking system for a vehicle is configured to carry out the method.