MRF Joystick Detents for Work Vehicle Function Triggering

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Solution Overview

Problem

Current joystick systems in work vehicles lack advanced features to enhance safety and efficiency, particularly in dynamic environments, and fail to provide intuitive and customizable resistance mechanisms for triggering various vehicle functions.

Innovation Solution

A magnetorheological fluid (MRF) joystick system with a controllable resistance mechanism and a controller architecture that generates detents to vary joystick stiffness, allowing for selective activation of work vehicle functions based on joystick movement, enabling automated routines and operator-selected control modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional joystick systems are used in work vehicles, then the basic control function is provided, but the safety and efficiency in dynamic environments cannot be enhanced

Engineering Contradiction:

ImprovesafetyVSAvoidadvanced features

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The joystick resistance mechanism uses magnetorheological fluid whose viscosity can be dynamically adjusted via electromagnetic fields. The controller modifies the resistance characteristics in real-time based on joystick position and operational mode, enabling the system to adapt to different work conditions and enhance both safety and efficiency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the physical parameters of the joystick resistance mechanism by altering the magnetic field strength applied to the magnetorheological fluid. This allows the resistance torque to be varied across different operational modes (e.g., transport mode with higher resistance, work mode with lower resistance), providing enhanced safety and efficiency for specific tasks

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If magnetorheological fluid resistance mechanism is used, then customizable resistance and detent generation are achieved, but the system complexity increases

Engineering Contradiction:

Improvecustomizable resistanceVSAvoidsystem complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The magnetorheological fluid resistance mechanism serves multiple functions: providing adjustable resistance torque, generating detent positions for function triggering, and enabling different operational modes. This multi-functionality reduces the need for separate mechanical components, thereby managing complexity while enhancing ease of operation

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces traditional mechanical resistance mechanisms (springs, friction devices) with a magnetorheological fluid-based system controlled by electromagnetic fields. This substitution eliminates complex mechanical linkages and allows for precise, programmable resistance characteristics, improving ease of operation while managing overall system complexity through electronic control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Extent of automation

If detent positions are generated for triggering functions, then the activation of work vehicle functions is enabled, but the joystick stiffness varies which may affect operation smoothness

Engineering Contradiction:

Improvefunction activationVSAvoidoperation smoothness

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

The controller dynamically adjusts the magnetorheological fluid resistance during joystick movement. When approaching a detent position, the resistance is increased to provide tactile feedback and ensure accurate function triggering. After passing the detent, the resistance is reduced again to maintain smooth operation. This dynamic adjustment enables automated function activation while preserving operation smoothness

Inventive Principle:

Principle #15Dynamics

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

The MRF joystick system improves operator convenience and efficiency by providing precise and customizable resistance, enabling quick response times, reduced frictional losses, and noiseless operation, allowing for seamless execution of work vehicle functions.

Implementation Method 1

An MRF joystick resistance mechanism is controllable to vary a joystick stiffness resisting movement of the joystick relative to the base housing

Methodology Applied

Scientific EffectMagnetorheological effect: Magnetorheological Fluid

Data Source

PatentUS11512446B2Magnetorheological fluid joystick systems providing detent-triggered work vehicle functions

Publication Date: 2022.11.29 DEERE & CO

AI summary

Embodiments of a work vehicle magnetorheological fluid (MRF) joystick system includes a joystick device having a base housing, a joystick movably mounted to the base housing, and a joystick position sensor monitoring movement of the joystick relative to the base housing. An MRF joystick resistance mechanism is controllable to vary a joystick stiffness resisting movement of the joystick relative to the base housing in at least one degree of freedom. A controller architecture is coupled to the joystick position sensor and to the MRF joystick resistance mechanism. The controller architecture is configured to: (i) command the MRF joystick resistance mechanism to increase the joystick stiffness when the joystick is moved into a first predetermined detent position to generate a first MRF detent; and (ii) selectively activate a first detent-triggered function of the work vehicle based, at least in part, on joystick movement relative to the first MRF detent.