Adaptive Hill Descent Speed Control via Wheel Grip Detection
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Solution Overview
Problem
Existing motor vehicle speed control systems on slopes, particularly under low grip conditions such as snow or ice, often lower vehicle speed excessively, leading to potential deviations from the trajectory and increased accident risks.
Innovation Solution
A method that automatically adjusts the target descent speed based on wheel grip conditions, using a low grip detection function, outside temperature information, and vehicle behavior analysis to implement adaptive braking strategies through the ABS system, reducing the target speed only as necessary to maintain safety and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target speed is lowered excessively under low grip conditions, then safety is improved, but the risk of trajectory deviation and accident increases
Solution Approach 1:
The system dynamically adjusts the target speed parameter based on detected grip conditions and criticality levels. Instead of using a fixed speed reduction, the controller modifies the target speed parameter in real-time according to wheel grip information and vehicle behavior analysis, resolving the contradiction by finding the optimal speed parameter for each specific condition
Solution Approach 2:
The system continuously monitors wheel grip conditions, vehicle behavior, and trajectory deviations, then feeds this information back to adjust the target speed. This closed-loop feedback mechanism allows the system to respond to changing conditions and prevent trajectory deviation while maintaining safety
2Stability of the object's composition
If the target speed is reduced to maintain safety on slopes, then vehicle stability is improved, but driving performance and response time deteriorate
Solution Approach 1:
The system implements dynamic speed adjustment rather than fixed speed limiting. The target speed is continuously adapted based on real-time detection of grip conditions, slope changes, and vehicle behavior, allowing the vehicle to maintain maximum safe speed under varying conditions rather than being constrained by a predetermined speed limit
Solution Approach 2:
The system performs preliminary detection of low grip conditions and predicts potential stability issues before they occur. By detecting criticality criteria in advance and preemptively adjusting the target speed, the system maintains vehicle stability while minimizing unnecessary speed reductions
3Reliability
If automatic speed control is implemented on slopes, then safety is improved, but the complexity of the control system increases
Solution Approach 1:
The system uses existing sensors and control components (wheel speed sensors, ABS/ESP systems, throttle control) for multiple functions. The same sensors used for basic ABS/ESP operations are also utilized for detecting low grip conditions and controlling hill descent speed, avoiding the need for dedicated additional hardware and reducing overall system complexity
Solution Approach 2:
The control system leverages information already available from the vehicle's existing detection functions (wheel slip detection, slope sensors, ABS/ESP status) to automatically determine when speed control is needed. The system serves itself by using its own operational data to trigger and adjust the speed control function
Data Source
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Figure 3
AI summary
Method for controlling the speed of a motor vehicle on a slope, the motor vehicle comprising an antilock braking system ABS allowing the wheels to be braked independently, this method automatically limiting the speed of the vehicle on downhill slopes to a target speed when the driver releases the accelerator pedal, characterized in that it reduces the target speed according to low wheel grip information given by a low grip detection function.