Electronic Joystick Dual-Spring Force Feedback

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Solution Overview

Problem

Electronic joysticks in work vehicles lack the force-related feedback provided by conventional hydraulically-linked joysticks, making it difficult for operators to control the vehicle, especially when performing precise tasks like maneuvering through tight spaces.

Innovation Solution

An electronic joystick system that includes a controller and a dual-spring configuration to vary the joystick force as it moves across the start/stop position, along with a vibration source to provide tactile feedback, mimicking the feedback of hydraulically-linked joysticks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional hydraulically-linked joysticks are used, then force-related feedback is provided to the operator, but the system complexity and hydraulic pressure requirements increase

Engineering Contradiction:
Improveoperator control feedbackVSAvoidhydraulic system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the conventional hydraulically-linked joystick system with an electronic joystick that uses electrical signals instead of hydraulic pressure. This substitution eliminates the need for complex hydraulic connections while maintaining operator control capability through electronic actuation of the hydrostatic drive unit.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a controller as an intermediary component that receives electrical signals from the electronic joystick and translates them into control commands for the hydrostatic drive unit. This mediator enables the decoupling of the joystick from direct hydraulic pressure while preserving the control feedback function through electronic signal processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If electronic joysticks are used to simplify the system, then hydraulic connections are eliminated, but force-related feedback at the start/stop position is lost

Engineering Contradiction:
Improvehydraulic connection complexityVSAvoidstart/stop position detection
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism where the controller monitors the joystick position and detects when the joystick crosses the start/stop position threshold. This feedback loop provides the operator with tactile or visual confirmation of the start/stop point, replacing the hydraulic pressure feedback that would naturally occur in conventional systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the physical parameter from hydraulic pressure to electrical signal parameters. By monitoring changes in electrical signal characteristics (voltage, current, or digital values) as the joystick moves, the system can detect the start/stop position without relying on hydraulic pressure changes, thus maintaining position detection capability while using an electronic system.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single spring is used in the electronic joystick, then the structure is simplified, but the ability to provide variable force feedback at different positions is reduced

Engineering Contradiction:
Improvespring configuration complexityVSAvoidjoystick force control
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent divides the spring system into multiple segments or uses multiple springs with different characteristics. This segmentation allows each spring to contribute to the overall force feedback in a specific way, enabling variable force feedback at different joystick positions while maintaining a manageable structural complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic spring characteristics where the spring force varies based on joystick position. This can be achieved through progressive spring rates, pre-loaded springs, or springs with varying wire diameters along their length, allowing the system to provide appropriate force feedback at neutral, start/stop, and full-stroke positions without requiring an overly complex mechanical structure.

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

Enhances operator control by providing significant force changes and vibratory feedback at the start/stop position, allowing for precise vehicle control and improved controllability.

Implementation Method 1

The first spring is configured to apply a first force against the electronic joystick as the electronic joystick is moved from the neutral position

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the second spring is configured to apply a second force against the electronic joystick as the electronic joystick is moved across the start/stop position such that the rate of change in the joystick force is increased across the start/stop position

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

The vibration source is configured to generate a vibratory response when the electronic joystick is moved across a start/stop position defined between the neutral and full stroke positions

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP2827218B1Joystick with improved control for work vehicles
Publication Date: 2020.10.14 CNH IND ITALIA SPA
  • EP2827218B1 patent drawingFigure 1
  • EP2827218B1 patent drawingFigure 2
  • EP2827218B1 patent drawingFigure 3

AI summary

A system (100) for controlling a work vehicle (10) is disclosed. The system (100) may include a controller (102) configured to control motion of the work vehicle (10) and an electronic joystick (300, 400) communicatively coupled to the controller (102). The electronic joystick (300, 400) may be configured to transmit signals to the controller (102) as it is moved between a neutral position (200) and a full stroke position (304, 306, 404, 406). The joystick (300, 400) may also be configured such that a varying joystick force is required to move the joystick (300, 400) between the neutral (302, 402) and full stroke positions (304, 306, 404, 406). In addition, a rate of change of the joystick force may be varied as the electronic joystick (300, 400) is moved across a start/stop position (200) defined between the neutral (302, 402) and full stroke positions (304, 306, 404, 406).