Brake Force Distribution Controller for Stationary Steering
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Solution Overview
Problem
Steering systems in vehicles face high steering effort when stationary with brakes engaged, particularly in heavy vehicles, due to significant static frictional forces, which can exceed the capabilities of manual steering and require powerful assistance systems, leading to increased weight, cost, and effort.
Innovation Solution
A controller-based system that redistributes braking force by releasing brakes from steered wheels when stationary, prioritizing brakes on wheels with greater steering contribution, reducing the load on the steering system and allowing steered wheels to rotate freely, thereby reducing the required steering force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If brakes are engaged on steered wheels when the vehicle is stationary, then the vehicle remains stable and stationary, but the steering force required to overcome static friction becomes excessively high
Solution Approach 1:
The braking force is segmented and distributed selectively among different wheels rather than applying equal brake force to all wheels. The controller individually controls brake force on steered versus non-steered wheels, releasing brakes on steered wheels when stationary to reduce steering effort while maintaining vehicle stability through controlled brake distribution.
Solution Approach 2:
Different braking characteristics are applied to different wheels based on their functional requirements. Non-steered wheels maintain brake engagement for stability, while steered wheels have brakes released to allow free rotation during steering maneuvers, creating local quality differences in brake application across the vehicle's wheel system.
2Ease of operation
If powerful steering assistance systems are used to overcome high static friction, then steering capability is improved, but the weight and cost of the steering system increases
Solution Approach 1:
The system performs preliminary action by proactively releasing brakes on steered wheels before steering maneuvers are initiated. This preliminary brake release eliminates the need for powerful steering assistance systems by removing the source of high static friction in advance, thereby reducing steering system weight and complexity.
Solution Approach 2:
The invention converts the harmful effect of engaged brakes (high static friction opposing steering) into a beneficial state by selectively releasing brakes on steered wheels. This transformation allows the steering system to operate with reduced power requirements while maintaining vehicle stability through controlled brake distribution on non-steered wheels.
3Ease of operation
If high steering ratio is used to provide mechanical advantage for manual steering, then steering effort is reduced, but the turning radius and maneuverability are adversely affected
Solution Approach 1:
By releasing brakes on steered wheels before steering input is applied, the system creates a preliminary condition where the wheels can rotate with minimal resistance. This eliminates the need for high steering ratios to overcome brake-induced friction, allowing for lower steering ratios that maintain better turning radius and maneuverability.
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
This approach decreases the steering force needed, enabling the use of less powerful steering components, reducing weight and cost, and improving turning radius and parking maneuvers, especially in automated steering systems.
Implementation Method 1
a static frictional force between the vehicle tires and the road surface must be overcome to steer the wheels
Data Source
AI summary
A system includes a controller configured to individually control brake force applied to steered wheels of a vehicle. The controller is configured to release a braking force from a first brake associated with a first steered wheel of the vehicle when the vehicle is stationary, and the controller is further configured to subsequently release a braking force from a second brake of a second steered wheel when the vehicle remains stationary after braking force is released from the first wheel. Methods relate to distributing braking force of a vehicle.