Automatic Brake Hold Control for Low-Gradient EV Rolling
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Solution Overview
Problem
Electric vehicles without a creep function may roll excessively on flat surfaces when stopped, as there is no torque to hold them stationary, potentially going unnoticed by the driver.
Innovation Solution
A controller system that automatically applies the brakes when the vehicle is stopped on a slope with a small gradient, using sensors to detect vehicle speed and gradient, and timers to determine when to apply the brakes to prevent rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If no creep torque is provided in electric vehicles, then the driver can modulate vehicle speed using only the accelerator pedal, but the vehicle may start to roll excessively on flat surfaces when stopped, potentially in a manner imperceptible to the driver
Solution Approach 1:
The system uses the vehicle's own sensors (accelerometer, speed sensor) and existing brake system to automatically detect and correct rolling conditions without external intervention. The controller monitors vehicle state and autonomously applies braking torque when rolling is detected, making the vehicle self-regulating for stability.
Solution Approach 2:
The system continuously monitors vehicle speed and acceleration data from sensors, compares this against thresholds to detect rolling conditions, and provides feedback control by automatically applying brake torque when rolling is detected. This closed-loop feedback ensures stability while maintaining driver control through the accelerator pedal.
2Stability of the object's composition
If automatic brake application is implemented to prevent rolling, then vehicle stability is improved, but the system complexity increases due to additional sensors and control logic
Solution Approach 1:
The system uses existing vehicle sensors (accelerometer for gradient detection, speed sensor for motion detection) and the existing brake system for multiple purposes: normal braking, creep torque simulation, and automatic rolling prevention. This multi-functionality avoids adding dedicated hardware while achieving stability control.
Solution Approach 2:
The vehicle's existing sensor suite and brake system are leveraged to provide automatic rolling prevention without requiring dedicated additional hardware. The controller processes existing sensor data and autonomously controls the brake system, minimizing added complexity while achieving the stability function.
Data Source
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AI summary
A controller for a vehicle, a system, a vehicle, a method, a computer program and a non-transitory computer-readable storage medium are disclosed. The controller is configured to receive an indication of a measured speed of the vehicle, and determine whether a gradient on which the vehicle is located is below a threshold gradient. The controller is also configured to provide an output signal to cause a brake of the vehicle to be automatically applied to hold the vehicle stationary, in dependence on: the received indication of the measured speed of the vehicle being below a threshold speed; and the determination that the gradient is below the threshold gradient.