Wheel Slip Control Using Displacement-Based Torque Redistribution

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Solution Overview

Problem

Vehicle wheels may slip on uneven ground surfaces due to excessive torque exceeding traction limits, which are influenced by vertical displacement and friction, leading to instability and control issues.

Innovation Solution

A system determines traction limits for each wheel based on vertical displacement and estimated friction, and redistributes torque among the wheels to prevent slip by adjusting torque distribution dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If high torque is provided to wheels to accelerate the vehicle, then vehicle acceleration performance is improved, but wheel slip occurs on uneven ground surfaces

Engineering Contradiction:

Improvevehicle accelerationVSAvoidwheel traction control

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent segments the total torque request into individual wheel torque allocations by determining separate traction limits for each wheel based on their specific vertical displacements and friction conditions. This allows independent torque control for each wheel to prevent slip while maintaining acceleration performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts torque distribution to each wheel in real-time based on changing vertical displacements and friction conditions. The traction limits and torque allocations are continuously updated as the vehicle encounters varying terrain, enabling adaptive slip prevention while maintaining acceleration capability.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If torque is distributed evenly to all wheels, then system simplicity is maintained, but wheel slip occurs when vertical displacements and friction vary among wheels

Engineering Contradiction:

Improvetorque distribution systemVSAvoidwheel slip prevention

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by determining individual traction limits for each wheel based on their specific vertical displacements and friction conditions rather than using a uniform approach. Each wheel receives torque allocation tailored to its local conditions, optimizing slip prevention without requiring overly complex system-wide adjustments.

Inventive Principle:

Principle #3Local quality

3Reliability

If torque is reduced to prevent wheel slip, then wheel traction control is improved, but vehicle acceleration performance decreases

Engineering Contradiction:

Improvewheel slip controlVSAvoidvehicle acceleration

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The system changes the parameter of torque allocation from a fixed or uniform value to a dynamic value based on calculated traction limits. By adjusting torque to match the maximum available traction for each wheel, the system prevents slip while maximizing acceleration performance without unnecessary torque reduction.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12545122B2Pre-emptive wheel slip control by wheel displacement

Publication Date: 2026.02.10 RIVIAN HOLDINGS LLC

AI summary

Methods and systems are provided for determining a plurality of traction limits corresponding to each of a plurality of wheels of a vehicle and determining a grounded torque request. Based on the plurality of traction limits, the grounded torque request is distributed to each of the plurality of wheels. If a grounded torque request to a first wheel of the plurality of wheels exceeds a traction limit for the first wheel, the torque to the first wheel may be reduced, and an increased torque is applied to a second wheel of the plurality of wheels.