MRF Joystick Return Position Adjustment for Work Vehicles
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Solution Overview
Problem
Current work vehicle joystick systems lack the ability to efficiently adjust joystick return positions to operator preferences, which can lead to reduced safety and efficiency due to inadequate ergonomic customization.
Innovation Solution
A magnetorheological fluid (MRF) joystick system with a controllable resistance mechanism and a joystick return position (JRP) locking mechanism, allowing operators to adjust the joystick return position manually by varying the MRF resistance force and locking mechanism states, enabling precise customization to operator preferences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed joystick return position is used, then the device complexity is reduced, but the adaptability to different operator preferences deteriorates
Solution Approach 1:
The joystick system transitions from a fixed return position to a dynamically adjustable one. The controller enables operators to modify the return position of the joystick, and the system adapts by adjusting the magnetic field strength of the magnetorheological fluid mechanism to maintain the new position, resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The system changes the physical parameter of the magnetorheological fluid (viscosity/resistance force) through electromagnetic field control. By varying the electrical current to the electromagnetic actuator, the system dynamically adjusts the resistance force to hold the joystick at different return positions, enabling customization without mechanical reconfiguration.
2Ease of operation
If operator adjustment of joystick return position is enabled, then ergonomic customization is improved, but the reliability of joystick positioning during operation deteriorates
Solution Approach 1:
The system performs preliminary locking of the joystick return position during normal operation. The controller maintains a predetermined level of resistance force that prevents unintended movement, while still allowing intentional operator adjustments when desired. This preliminary stabilization ensures reliability during operation while preserving ergonomic customization capability.
Solution Approach 2:
The controller continuously monitors joystick position and adjusts the magnetorheological fluid resistance force in real-time to maintain the desired return position. This closed-loop feedback mechanism ensures that once a return position is set, it remains stable and reliable during operation, preventing drift or unintended changes.
3Reliability
If maximum MRF resistance force is applied to prevent joystick movement, then the reliability of joystick positioning is improved, but the ease of operation for adjustment deteriorates
Solution Approach 1:
The system applies maximum MRF resistance force periodically or temporarily only during adjustment operations. When an operator initiates a return position adjustment, the controller temporarily reduces the resistance force to allow movement, then reapplies maximum force once the adjustment is complete to prevent unintended movement. This periodic application resolves the contradiction between reliability and ease of adjustment.
Solution Approach 2:
The resistance force dynamically transitions between low and high states based on operational context. During normal operation, maximum resistance force maintains reliability. During adjustment mode, the resistance force is temporarily reduced to facilitate easy repositioning, then restored to maximum when adjustment completes, allowing both reliability and ease of operation at different times.
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 enhances operator comfort and reduces ergonomic stress by allowing customizable joystick return positions, improving safety and efficiency during prolonged vehicle operations.
Implementation Method 1
An MRF joystick resistance mechanism is controllable to vary an MRF resistance force impeding movement of the joystick relative to the base housing
Implementation Method 2
a spring contained in the base housing and exerting a resilient bias force on the joystick urging the joystick toward a joystick return position
Data Source
AI summary
In embodiments, a work vehicle magnetorheological fluid (MRF) joystick system includes a joystick device. The joystick device includes, in turn, a base housing and a joystick, which is rotatable relative to the base housing and which is biased toward a joystick return position. An MRF joystick resistance mechanism is controllable to vary an MRF resistance force impeding movement of the joystick relative to the base housing, while a controller architecture is coupled to the MRF joystick resistance mechanism. The controller configured to: (i) selectively enable an operator adjustment of the joystick return position by a work vehicle operator; and (ii) when enabling the operator adjustment of the joystick return position, command the MRF joystick resistance mechanism to maintain the MRF resistance force at a predetermined level until the operator adjustment of the joystick return position is terminated.