Electric Vehicle Motor Control for ABS Stability
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Solution Overview
Problem
In electric vehicles, coordinated control between the brake control device and the electric motor is challenging when abnormalities occur in the control system, leading to instability and potential wheel locking, which affects steering stability.
Innovation Solution
A control apparatus that includes an electric motor controlled to a power running state with a predetermined torque, slip determining means to assess wheel slipping, and motor control means to prohibit regenerative braking when abnormalities are detected, ensuring the electric motor operates within safe torque limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is used during ABS control, then energy recovery is improved, but vehicle stability deteriorates due to wheel locking
Solution Approach 1:
The control apparatus applies preliminary anti-action by detecting the operational state of the brake control device and proactively prohibiting regenerative braking when abnormalities are detected. This prevents the harmful effect of wheel locking before it occurs, ensuring vehicle stability is maintained while still allowing energy recovery during normal operation
Solution Approach 2:
The control apparatus uses feedback by continuously monitoring the operational state of the brake control device and adjusting the regenerative braking control accordingly. When the brake control device is operating normally, regenerative braking is permitted; when abnormalities are detected, regenerative braking is prohibited, creating a closed-loop control system that maintains vehicle stability
2Stability of the object's composition
If coordinated control between brake control device and electric motor is implemented, then vehicle behavior stability is improved, but system complexity increases when abnormalities occur
Solution Approach 1:
The control apparatus applies segmentation by dividing the control logic into distinct functional modules: a detection unit that monitors the operational state of the brake control device, and a control unit that executes different control strategies based on the detection results. This modular approach manages system complexity by separating concerns while maintaining coordinated control for vehicle stability
Solution Approach 2:
The control apparatus uses dynamics by adapting the control strategy based on the operational state of the brake control device. The system dynamically switches between permitting and prohibiting regenerative braking according to real-time conditions, allowing the control system to remain simple under normal conditions while maintaining stability when abnormalities occur
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 stabilizes vehicle behavior by preventing regenerative braking during abnormalities, maintaining vehicle stability and improving steering stability by controlling the electric motor to a power running torque that prevents wheel locking.
Implementation Method 1
the electric motor is operated as a power generator during vehicle braking such that the vehicle is braked using a regenerative torque generated by the electric motor
Implementation Method 2
a friction brake such as a disk brake alongside the regenerative brake
Data Source
AI summary
When a diagnosis result of an ABS control system is normal, a determination is made as to whether or not to execute ABS control based on a slip ratio of a vehicle wheel, whereupon motor torque control is executed based on an operational state of an ABS. In other words, when ABS control is not executed, the motor-generator is controlled to a regenerative state, and when ABS control is executed, the motor-generator is controlled to a power running state. When the diagnosis result of the ABS control system is abnormal, on the other hand, regenerative braking by the motor-generator is prohibited immediately and the motor-generator is controlled to the power running state.