Vehicle Brake Torque Switching Control for Smooth Stops on Slopes
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Solution Overview
Problem
Existing vehicle control systems experience sudden changes in braking torque during transitions between regenerative and mechanical braking, leading to uncomfortable rides and difficulty in smooth stopping, especially on sloping surfaces.
Innovation Solution
A control device that adjusts the output torque of the rotating electrical machine to compensate for deviations in mechanical braking torque, using sensors and ECUs to calculate and correct the regenerative torque based on actual and ideal braking values, setting upper and lower limits to stabilize the vehicle's stopping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching control is performed between regenerative braking and mechanical brake, then braking torque can be maintained, but sudden changes in acceleration cause large correction amounts that lead to uncomfortable rides
Solution Approach 1:
The patent applies preliminary action by calculating and storing the gravitational acceleration component before switching control begins. This pre-calculated value is then used during switching control to compensate for acceleration changes, preventing large correction amounts and ensuring smooth braking transitions without affecting braking torque maintenance
Solution Approach 2:
The patent uses feedback by continuously monitoring vehicle acceleration and comparing it with the pre-calculated gravitational acceleration component. The difference is fed back to adjust the regenerative braking torque correction amount, ensuring that braking torque is maintained while compensating for acceleration changes that would otherwise cause ride discomfort
2Measurement precision
If regenerative braking torque is increased to compensate for mechanical brake deviation, then braking accuracy improves, but torque changes suddenly causing stop failure
Solution Approach 1:
The patent applies preliminary action by pre-calculating the gravitational acceleration component and storing it before switching control begins. This pre-computed value is used to adjust the regenerative braking torque correction, preventing sudden torque changes that would cause stop failure while maintaining braking accuracy through proper compensation
3Reliability
If switching from regenerative braking to mechanical brake is performed, then braking force can be maintained, but control complexity increases due to multiple correction calculations
Solution Approach 1:
The patent reduces control complexity by applying preliminary action - the gravitational acceleration component is calculated and stored once before switching control begins, rather than being recalculated continuously. This pre-computed value is then reused during switching control, simplifying the overall control calculations while maintaining reliable braking force
Solution Approach 2:
The system applies self-service by using the pre-calculated gravitational acceleration component to automatically compensate for acceleration changes during switching control. This self-compensation mechanism reduces the need for complex real-time calculations and multiple correction iterations, simplifying the control process while maintaining braking force
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
Ensures smooth stopping of the vehicle by stabilizing the braking force, preventing sudden changes in torque and maintaining control accuracy, even on sloping roads.
Implementation Method 1
a rotating electrical machine that is capable of functioning as a generator to generate braking torque by regenerative torque
Data Source
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AI summary
A control device (50) includes a switching control unit (55) and a difference acquisition unit (64). The switching control unit performs switching control that increases braking torque of a braking device while decreasing braking torque of a rotating electrical machine, when a vehicle is decelerated. The difference acquisition unit acquires a braking torque difference indicating a difference between braking torque required for keeping a stopped state of the vehicle and braking torque of the braking device, when the vehicle is stopped. After the information acquisition unit detects the stopped state of the vehicle, the switching control unit corrects output torque of the rotating electrical machine based on the braking torque difference.