Autonomous Vehicle Friction Estimation via Embedded Wheel Actions

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Solution Overview

Problem

Current computing systems in vehicles, both autonomous and non-autonomous, face challenges in accurately determining friction levels on driving surfaces, which can affect navigation and control, particularly during events like acceleration, deceleration, or stopping, without causing noticeable disruptions to passengers.

Innovation Solution

A computing system that detects events such as acceleration, deceleration, or stopping and uses operational data to determine friction levels by initiating wheel-based actions like steering, braking, or propulsion, minimizing passenger perception while obtaining necessary operational data to calculate friction between tires and the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wheel-based actions (steering, braking, propulsion) are initiated to obtain operational data for friction calculation, then measurement precision of friction levels is improved, but passengers may perceive disruptions during these actions

Engineering Contradiction:
Improvefriction level measurementVSAvoidpassenger perception of disruption
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs friction measurements during pre-planned wheel-based actions (steering, braking, propulsion) that are already scheduled as part of normal vehicle operation. By embedding the measurement actions within the vehicle's existing motion plan, the system obtains friction data without adding extra disruptive maneuvers.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The vehicle's own operational movements (steering, braking, propulsion) are utilized to generate the wheel-based actions needed for friction measurement. The vehicle serves its own measurement needs by using its normal operational repertoire, eliminating the need for separate dedicated measurement maneuvers that would disrupt passengers.

Inventive Principle:
Principle #25Self-service

2Reliability

If friction data is obtained through dedicated wheel-based actions, then reliability of friction estimation is improved, but vehicle operation time is increased

Engineering Contradiction:
Improvefriction estimation accuracyVSAvoidvehicle operation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system combines friction measurement objectives with the vehicle's existing operational actions. Wheel-based actions originally planned for navigation or control purposes are merged with friction estimation objectives, allowing the vehicle to achieve both its operational goal and friction data collection without additional time expenditure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The wheel-based actions are designed to serve multiple functions simultaneously: they perform the vehicle's primary operational task (steering, braking, or propulsion) while also generating the operational data needed for friction estimation. This multi-functionality eliminates the need for separate dedicated measurement maneuvers.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If multiple wheel-based actions are initiated for comprehensive friction measurement, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvefriction level measurementVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses feedback from the vehicle's existing sensors (wheel speed, steering angle, brake pressure) to determine when wheel-based actions have generated sufficient operational data for accurate friction estimation. This feedback mechanism allows the system to adaptively decide when measurements are complete without requiring complex predetermined sequences.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system monitors changes in operational parameters (wheel speed, steering angle, brake pressure) during wheel-based actions to assess friction conditions. By tracking parameter changes rather than requiring fixed measurement protocols, the system achieves comprehensive friction measurement with simpler control logic.

Inventive Principle:
Principle #35Parameter changes

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

Enables vehicles to accurately estimate friction levels during various events, improving navigation and control by using friction data for motion planning, route optimization, and reducing the risk of accidents by tailoring vehicle movements based on surface conditions.

Implementation Method 1

determining, based at least in part on the operational data, data indicative of a friction associated with a surface upon which the autonomous vehicle is traveling during the event

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentUS11427223B2Driving surface friction estimations for autonomous vehicles
Publication Date: 2022.08.30 UATC LLC
  • US11427223B2 patent drawing
  • US11427223B2 patent drawing
  • US11427223B2 patent drawing

AI summary

Systems and methods are provided for generating data indicative of a friction associated with a driving surface, and for using friction data as part of controlling autonomous vehicle operations. In one example, a computing system can detect an event including at least one of an acceleration, a deceleration, or a stop associated with an autonomous vehicle and obtain, in response to detecting the event, operational data associated with the autonomous vehicle during the event. The computing system can determine, based at least in part on the operational data, data indicative of a friction associated with a surface upon which the autonomous vehicle is traveling during the event. The computing system can control the autonomous vehicle based at least in part on the data indicative of the friction associated with the surface.