Wheel Slip Limit Control for Low Wear and Maneuver Force
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Solution Overview
Problem
Existing vehicle control systems fail to provide appropriate slip limit values, leading to increased wheel wear and rolling resistance during normal operations, while high slip limit values are necessary for infrequent maneuvers.
Innovation Solution
A method and control unit to determine a slip limit value for vehicle wheels, setting it lower for normal operations and higher for infrequent maneuvers, based on vehicle conditions and predicted maneuvers, to optimize wheel performance and reduce wear and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high slip limit values are used for vehicle control, then adequate wheel force is available for maneuvers, but wheel wear rate and rolling resistance increase during normal operations
Solution Approach 1:
The patent applies dynamics by making the slip limit value adjustable rather than fixed. The control unit dynamically changes the slip limit value between a first value (for normal operations) and a second value (for infrequent maneuvers) based on detected vehicle conditions. This allows the system to optimize between wheel force availability and wheel wear rate by adapting the slip limit to current operational requirements.
Solution Approach 2:
The patent changes the parameter of slip limit value from a constant high value to a variable parameter that can take on different values based on operating conditions. By switching between a first slip limit value (lower) for frequent operations and a second slip limit value (higher) for infrequent maneuvers, the system resolves the contradiction between maintaining adequate wheel force and minimizing wheel wear rate.
2Force
If high slip limit values are used for vehicle control, then adequate wheel force is available for maneuvers, but fuel economy deteriorates due to increased rolling resistance
Solution Approach 1:
The system dynamically adjusts the slip limit value based on detected vehicle conditions to optimize energy efficiency. During normal operations, a lower first slip limit value reduces rolling resistance and improves fuel economy. When infrequent maneuvers are detected, the system switches to a higher second slip limit value to ensure adequate wheel force is available, thus resolving the energy-efficiency contradiction.
Solution Approach 2:
The patent changes the slip limit parameter from a fixed high value to a variable parameter that switches between a first value and a second value. This parameter adaptation allows the system to minimize rolling resistance and improve fuel economy during normal operations while maintaining adequate wheel force availability when needed for infrequent maneuvers.
3Object-generated harmful factors
If moderate slip limit values are used during normal operations, then wheel wear rate and rolling resistance are reduced, but wheel force availability decreases for maneuvers
Solution Approach 1:
The control system dynamically switches between a first slip limit value (moderate, for normal operations) and a second slip limit value (higher, for infrequent maneuvers) based on detected vehicle conditions. This dynamic adjustment ensures that moderate slip limit values are used during normal operations to reduce wheel wear rate, while adequate wheel force availability is maintained when infrequent maneuvers are detected.
Data Source
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AI summary
The present invention relates to a method for determining a slip limit value (sx,lim; αlim) for a wheel (14, 16) of a vehicle (10). The slip limit value (sx,lim; αlim) is used for controlling the operation of the vehicle (10). The method comprises setting the slip limit value (sx,lim; αlim) to be smaller than a high slip limit value (sx,lim2; αlim2) for a majority of an operating time of the vehicle (10). The method further comprises: - determining whether or not the vehicle (10) assumes an infrequent manoeuvre condition in which the vehicle (10) carries out an infrequent manoeuvre and/or or is predicted to carry out an infrequent manoeuvre within a predetermined time range, - in response to determining that the vehicle (10) assumes the infrequent manoeuvre condition, setting the slip limit value to the high slip limit value (sx,lim2; αlim2).