Steering Angle Alignment for Smooth Manual-Autonomous Transitions

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Solution Overview

Problem

Existing steering systems, particularly non-mechanically linked electro-hydraulic systems, face challenges in transitioning between manual and autonomous operating modes without providing feedback to operators about autonomous actions and ensuring smooth mode transitions.

Innovation Solution

An electronic control unit (ECU) receives instructions from an autonomous vehicle controller to align the steering controller angle with the machine steering angle, allowing for efficient transitions between modes by providing currents to both the steering controller and hydraulic actuator, and determining manual input thresholds for mode switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a non-mechanically-linked electro-hydraulic steering system is used, then the steering controller subsystem and hydraulic machine steering subsystem can operate independently, but feedback to the operator regarding autonomous actions is not provided and smooth transition between modes is not achieved

Engineering Contradiction:

Improveindependent operation of steering subsystemsVSAvoidoperator feedback on autonomous actions

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The ECU provides feedback to the operator by rotating the steering controller to match the machine steering angle during autonomous operation. This visual feedback mechanism allows the operator to see the steering position that the autonomous system is commanding, maintaining awareness of autonomous actions while preserving independent subsystem operation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The ECU acts as an intermediary between the autonomous vehicle controller and the steering controller. It receives machine steering angle commands, calculates the corresponding steering controller angle, and rotates the steering controller to match, thereby mediating the communication between autonomous system and operator interface.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a non-mechanically-linked electro-hydraulic steering system is used, then the steering controller subsystem and hydraulic machine steering subsystem can operate independently, but smooth transition between manual and autonomous modes is not achieved

Engineering Contradiction:

Improveindependent operation of steering subsystemsVSAvoidmode transition smoothness

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

Before transitioning between manual and autonomous modes, the ECU pre-positions the steering controller by rotating it to match the current machine steering angle. This preliminary alignment ensures that when the mode transition occurs, the steering controller is already in the correct position, enabling smooth transition without abrupt movements or operator confusion.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If the steering controller angle is not aligned with the machine steering angle during mode transition, then manual control can be maintained, but operator safety is compromised and system wear increases

Engineering Contradiction:

Improvemanual control maintenanceVSAvoidoperator safety

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The ECU performs preliminary alignment of the steering controller angle with the machine steering angle before and during mode transitions. This ensures that when the operator takes manual control, the steering controller is already positioned correctly, preventing unsafe situations where the controller and actual steering position would be misaligned, thereby maintaining both operator safety and manual control capability.

Inventive Principle:

Principle #10Preliminary action

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 solution enables smooth and efficient transitions between manual and autonomous modes, providing operator feedback and reducing wear and safety hazards by ensuring the steering controller angle is aligned with the machine steering angle, thus facilitating seamless operation.

Implementation Method 1

providing, by the ECU and to a steering controller torque device, a current to set a steering controller, of the vehicle, to a particular steering controller angle

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

providing, by the ECU and to a hydraulic control system, a current to set the hydraulic steering actuator to the particular machine steering angle setting

Methodology Applied

Scientific EffectHydraulic force: Hydraulic Press

Data Source

PatentUS11338848B2Alignment of steering controller angle and machine steering angle for transitioning between manual and autonomous operating modes

Publication Date: 2022.05.24 CATERPILLAR INC

AI summary

An electronic control unit (ECU) may receive, from an autonomous vehicle controller, an instruction to set a hydraulic steering actuator, of a vehicle, to a particular machine steering angle setting. The ECU may provide, to a steering controller torque device, a current to set a steering controller, of the vehicle, to a particular steering controller angle that corresponds to the particular machine steering angle setting. The ECU may provide, to a hydraulic control system, a current to set the hydraulic steering actuator to the particular machine steering angle setting.