ABS Braking Torque Distribution for Vehicle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle braking systems face challenges in maintaining control during emergency maneuvers, particularly on slippery or uneven road surfaces, where wheel locking can occur, leading to loss of stability and potential drifting.
Innovation Solution
A method and device that adjust the braking torque distribution across vehicle wheels based on lateral acceleration and turn dynamics, desensitizing the instability criterion for outer wheels and sensitizing it for inner wheels during turns, using a simple ABS system with four wheel speed sensors to prevent wheel locking and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the instability criterion is uniformly applied to all wheels during braking, then the braking control is simple, but the vehicle stability is reduced during turns due to wheel locking on slippery surfaces
Solution Approach 1:
The patent applies different instability criteria to different wheels based on their position during a turn. The inner wheel (wheel inside the curve) uses a more sensitive instability criterion while the outer wheel uses a less sensitive criterion. This local differentiation allows each wheel to be controlled according to its specific loading and slip characteristics during turning maneuvers, improving overall vehicle stability without requiring a completely complex control system.
Solution Approach 2:
The patent dynamically adjusts the instability criterion sensitivity based on detected turn conditions. When a turn is detected through lateral acceleration sensing, the system automatically modifies the instability criteria for different wheels. This dynamic adaptation allows the braking control system to respond appropriately to changing vehicle states during emergency maneuvers, enhancing reliability without permanent system complexity.
2Reliability
If the instability criterion is desensitized for outer wheels and sensitized for inner wheels during turns, then wheel locking is prevented, but the braking response time increases
Solution Approach 1:
The patent detects turn conditions in advance through lateral acceleration sensing and proactively adjusts the instability criteria before wheel locking occurs. By anticipating the different slip characteristics of inner and outer wheels during a turn, the system pre-configures appropriate sensitivity levels, preventing wheel locking while minimizing response time delay.
Solution Approach 2:
The patent changes the instability criterion parameters dynamically based on turn detection. The system modifies the sensitivity thresholds for different wheels according to their position in the turn, allowing optimized braking control that prevents wheel locking while maintaining fast response times through adaptive parameter adjustment rather than fixed conservative settings.
3Measurement precision
If additional sensors are added to detect turn conditions and improve braking distribution, then braking precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent makes the existing lateral acceleration sensor serve multiple functions: it detects both the magnitude and direction of turns, and this information is used to differentiate instability criteria for inner and outer wheels. By maximizing the utility of existing sensors, the system achieves precise turn detection and differentiated braking control without adding unnecessary sensor complexity.
Solution Approach 2:
The system uses information already available from the braking control system (wheel speeds, braking forces) combined with lateral acceleration data to self-determine turn conditions and automatically adjust instability criteria. The system serves itself by leveraging existing data streams, eliminating the need for additional dedicated sensors while maintaining measurement precision.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The method involves reducing a wheel brake locking set point when crossing of an instability criteria on a wheel is detected. A lateral acceleration of the wheel is calculated, where a non-zero value of the acceleration specifies a turn of a vehicle. The instability criteria is desensitized for an outer wheel, and is sensitized for an inner wheel during turning according to the acceleration having the non-zero value. An independent claim is also included for a braking device.