Electric Tractor Braking Control for Understeer Mitigation
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Solution Overview
Problem
Electric tractor trailer combination vehicles experience understeer when entering sharp turns, especially on low-friction road surfaces, which can lead to sub-optimal regenerative braking and reduced energy efficiency.
Innovation Solution
A computer system that receives a braking request and adjusts the braking forces on the tractor's rear drive axle and front axle to mitigate understeer by increasing regeneration on the rear axle and decreasing braking on the front axle, while maintaining a combined braking force that fulfills the braking request.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If regenerative braking is applied to individual wheels to mitigate understeer, then understeer tendency is reduced, but energy efficiency deteriorates due to sub-optimal regenerative braking
Solution Approach 1:
The system dynamically changes the braking force distribution parameters between front and rear axles based on real-time understeer tendency detection. When understeer is detected, the control system adjusts the braking force ratio to reduce understeer while optimizing regenerative braking engagement to maintain energy efficiency.
Solution Approach 2:
The system implements a feedback loop that continuously monitors vehicle parameters (steering angle, yaw rate, lateral acceleration) to detect understeer tendency, then adjusts the braking force distribution accordingly. This closed-loop control ensures that regenerative braking is optimized to maintain both stability and energy efficiency.
2Stability of the object's composition
If braking force is increased on rear axle to mitigate understeer, then handling stability is improved, but risk of wheel lockup increases on low-friction surfaces
Solution Approach 1:
The system applies different braking control strategies to different axles based on their specific roles and conditions. The rear axle receives increased braking force to counteract understeer, while the front axle maintains appropriate braking force for steering stability, with each axle's braking force independently optimized to prevent wheel lockup.
Solution Approach 2:
The braking force distribution is dynamically adjusted based on real-time road friction conditions and vehicle state. The system continuously modifies the braking force ratio between axles to maintain optimal handling stability while adapting to changing friction conditions to prevent wheel lockup.
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 solution effectively mitigates understeer in electric tractor trailer combination vehicles without sacrificing energy efficiency, allowing for improved handling and reduced risk of dangerous situations like jack-knifing.
Implementation Method 1
increase a braking force on the rear drive axle of the tractor using regeneration
Data Source
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Figure 3
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AI summary
A computer system comprising processing circuitry configured to: receive a braking request for braking a vehicle including an electrically powered tractor, and a trailer coupled to the tractor by an articulated coupling; provide a first braking command encoding instructions to control braking on at least a front axle of the tractor, and on a rear drive axle of the tractor to provide a combined braking force fulfilling the braking request; receive a first set of vehicle parameters; determine, based on the first set of vehicle parameters, that an understeer tendency of the vehicle during braking is higher than a predefined first understeer tendency threshold; and provide a second braking command encoding instructions to increase a braking force on the rear drive axle of the tractor using regeneration, and decrease a braking force on the front axle of the tractor, so that the combined braking force fulfills the braking request.