Obstacle Crawl Control Brake Torque Application
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Solution Overview
Problem
Conventional brake traction control systems and mechanical locking differentials struggle to maintain traction on split μ surfaces at low vehicle speeds, leading to potential loss of traction and difficulty in traversing obstacles like rocks, as they rely on predetermined wheel speed or torque differences for torque transfer.
Innovation Solution
The Obstacle Crawl Control (OCC) system applies a predetermined braking torque to the front wheels independently of wheel speed or torque differences, ensuring traction by initiating brake pressure as soon as the throttle is applied and maintaining it up to a certain threshold speed, effectively mimicking a mechanically locked differential at low speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brake traction control systems or mechanical locking differentials are used, then torque transfer can occur between drive wheels, but traction cannot be maintained at low vehicle speeds on split μ surfaces
Solution Approach 1:
The system applies preliminary braking torque to the drive wheels before wheel speed differences occur, based on detection of low vehicle speed conditions. This proactive approach prevents loss of traction rather than reacting after slip occurs, enabling reliable torque transfer at speeds where conventional systems fail.
Solution Approach 2:
The system dynamically adjusts brake torque application based on real-time vehicle speed conditions. At low speeds, predetermined brake torque is applied to maintain traction, while at higher speeds the system transitions to conventional traction control operation, creating a dynamic response that adapts to changing operational conditions.
2Reliability
If mechanical locking differential is used to deliver torque to the wheel with most traction, then traction control is achieved, but the system adds complexity and weight
Solution Approach 1:
The system replaces the mechanical locking differential with an electronically controlled brake-based traction control system. The controller applies predetermined brake torque to drive wheels based on speed and acceleration sensor data, eliminating the need for complex mechanical locking mechanisms while achieving the same traction control function.
Solution Approach 2:
The system changes the operational parameters of the brake system to achieve traction control. By applying predetermined brake torque at low speeds and adjusting brake pressure based on detected wheel speed and vehicle acceleration, the system achieves traction control through parameter modulation rather than mechanical locking.
3Reliability
If conventional traction control systems rely on predetermined wheel speed or torque differences, then torque transfer occurs between wheels, but the system cannot respond to low speed conditions where speed difference is minimal
Solution Approach 1:
The system performs preliminary traction control action based on vehicle speed thresholds before wheel speed differences become significant. By detecting low vehicle speed conditions and applying predetermined brake torque proactively, the system responds to traction needs before the minimal speed differences that conventional systems rely upon occur.
Solution Approach 2:
The system adds another dimension to traction control by incorporating vehicle acceleration detection alongside wheel speed measurement. This dual-parameter approach enables the system to detect traction conditions and respond appropriately even when wheel speed differences are minimal, providing more comprehensive traction control 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
The OCC system enhances traction control on split μ surfaces at low speeds, allowing vehicles to maintain position and progress over obstacles without the need for constant two-foot operation, thereby preventing unintended movement off the obstacle.
Implementation Method 1
The vehicle braking system can include friction members for controlling vehicle speed based on application of fluid pressure
Implementation Method 2
The vehicle braking system can include friction members for controlling vehicle speed based on application of fluid pressure
Data Source
AI summary
A brake traction control system for a vehicle a braking input member, a brake modulator and a controller. The braking input member can be manually actuated and controllable to manipulate the vehicle braking system by controlling the pressure. The brake modulator can be controllable to manipulate the vehicle braking system by controlling the pressure. The controller can be configured to control the brake modulator in an obstacle crawl control mode such that the controller controls the brake modulator to adjust the pressure. The controller can perform processing in the obstacle control mode including: performing a first determination to determine whether the acceleration input member is actuated to control the power source assembly to propel the vehicle; performing a second determination to determine whether a speed of the vehicle satisfies predetermined criteria; and controlling the pressure based on the first determination and the second determination.