Adaptive Hill-Hold Control for Vehicle Stability
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Solution Overview
Problem
Current hill-hold control systems uniformly apply braking pressure to all wheels, leading to over-braking and increased durability and noise-vibration-heat issues due to excessive pressure, and fail to optimize pressure levels for different wheels within a hydraulic unit.
Innovation Solution
An adaptive hill-hold control system that dynamically adjusts braking pressure at each wheel based on vehicle parameters, such as weight and road gradient, to minimize excess pressure and optimize pressure distribution across wheels, allowing for different pressure levels at various brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform braking pressure is applied to all wheels, then the vehicle is held in place, but excessive pressure is applied leading to increased durability requirements and noise-vibration-heat issues
Solution Approach 1:
The system applies different braking pressures to different wheels based on their individual requirements. The controller adjusts pressure levels locally at each wheel rather than applying uniform pressure, allowing optimal pressure distribution that maintains stability while reducing excessive pressure and associated NVH issues.
Solution Approach 2:
The braking pressure is dynamically adjusted based on real-time vehicle conditions, driver input, and wheel-specific parameters. The system transitions from static uniform pressure to dynamic adaptive pressure control, optimizing the balance between holding the vehicle and minimizing harmful effects.
2Device complexity
If uniform braking pressure is applied to all wheels, then the control strategy is simple, but it does not optimize pressure levels for different wheels within a hydraulic unit
Solution Approach 1:
The control system implements local quality by allowing each wheel to receive customized pressure levels based on its specific requirements, vehicle position, and hydraulic circuit characteristics, rather than applying a single uniform pressure to all wheels.
Solution Approach 2:
The braking system is segmented into independent controllable units at the wheel level, with the ability to apply different pressures to different wheels. This segmentation enables optimized pressure distribution across the vehicle while maintaining manageable control through the electronic control unit.
3Reliability
If more braking pressure is applied, then the vehicle is held more securely in place, but more current is required to control the switchover valve coil
Solution Approach 1:
The system changes the pressure parameter dynamically based on actual vehicle conditions rather than maintaining constant high pressure. By adjusting pressure levels to match the minimum required for hill-hold, the system reduces the current demand on the switchover valve coil while maintaining adequate holding capability.
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
Reduces noise-vibration-heat issues and increases durability by applying only the necessary pressure to hold the vehicle in place, enhancing the overall efficiency and longevity of the brake system while maintaining vehicle stability.
Implementation Method 1
a first wheel brake, a second wheel brake
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A hill-hold control system for a vehicle. The hill-hold control system includes a first wheel brake (120A, 120B), a second wheel brake (120C, 120D), a braking indicator (brake pedal), a drive away indicator (accelerator), and a controller (130). The controller is configured to determine that the vehicle is at standstill, detect from the braking indicator that braking is no longer desired, adjust a braking pressure at the first wheel brake, adjust a braking pressure at the second wheel brake, detect from the drive away indicator an operator's desire to drive away, and when the operator's desire to drive away is detected, removing the braking pressure at the first wheel brake and the braking pressure at the second wheel brake.