Adaptive Motor Current Gradient for Vehicle Braking Stability
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Solution Overview
Problem
The existing vehicle braking control systems face instability due to significant right-and-left braking force differences when motor protection control is initiated, limiting the opportunity for overheated motor protection and affecting vehicle behavior.
Innovation Solution
A vehicle braking control device with a temperature obtaining portion, determination portion, and motor control portion that gradually reduces the current value of an overheated motor based on its temperature, while adjusting the current value of normal motors to minimize braking force differences and stabilize vehicle behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motor protection control is performed by rapidly reducing the current value for the overheated motor, then the motor is protected from overheating damage, but the right-and-left braking force difference increases causing vehicle behavior instability
Solution Approach 1:
The patent applies dynamics by making the current reduction gradient adaptive rather than fixed. The control device dynamically adjusts the reduction gradient based on real-time temperature measurements, vehicle speed, and braking force requirements. This allows the system to transition between aggressive protection mode (when safe) and gentle adjustment mode (when stability is critical), resolving the contradiction between motor protection and vehicle stability.
Solution Approach 2:
The patent changes the parameter of current reduction gradient from a fixed value to a variable parameter that depends on temperature level and vehicle operating conditions. By introducing multiple threshold levels and adjusting the reduction gradient accordingly, the system optimizes the balance between protecting the motor and maintaining vehicle stability under different operating scenarios.
2Stability of the object's composition
If the determination criteria for vehicle stability are set severely to avoid vehicle spin, then vehicle behavior stability is maintained, but the opportunity to perform motor protection control is limited
Solution Approach 1:
The patent makes the protection control activation dynamic by continuously monitoring temperature trends and vehicle operating conditions. Instead of using fixed severe criteria that prevent protection control, the system adaptively determines when protection control is safe to implement based on real-time feedback, thereby increasing protection opportunities while maintaining stability.
Solution Approach 2:
The system employs feedback mechanisms by continuously monitoring vehicle speed, braking force requirements, and temperature changes during protection control execution. This feedback allows the control device to adjust the reduction gradient in real-time, ensuring vehicle stability is maintained while enabling more frequent protection control activation.
3Temperature
If the current value for the overheated motor is reduced at a steep gradient, then the temperature increase of the motor is limited, but the braking force difference between left and right wheels increases rapidly
Solution Approach 1:
The patent changes the reduction gradient from a fixed steep value to a variable parameter that adapts based on temperature level and vehicle conditions. By introducing multiple temperature thresholds and corresponding gradient levels, the system achieves effective temperature control while managing braking force differences appropriately for each operating scenario.
Solution Approach 2:
The system dynamically adjusts the current reduction gradient based on real-time temperature measurements and vehicle operating conditions. This dynamic approach allows aggressive temperature control when conditions permit, while transitioning to gentler adjustment when vehicle stability is concerned, resolving the contradiction between temperature control effectiveness and braking force balance.
Data Source
AI summary
Each of a plurality of electric brake devices corresponds to one of a plurality of wheels and includes a motor. A brake ECU, which controls the electric brake devices, determines whether there is an overheated motor of which the temperature T is greater than or equal to a first set threshold value Tth1. Also, when there is only one overheated motor, the brake ECU reduces a current value Ix for the overheated motor at a more gradual gradient in the case where the temperature T of the overheated motor is low than in the case where the temperature is high.