Force-Sensing Joystick Feedback With Auto-Calibration and Variable Hold
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Solution Overview
Problem
Current operator-controlled signal output devices face issues with electromagnetic hold requiring large coils, leading to space and cost inefficiencies, and lack variable feel and auto-calibration features, resulting in undesirable feedback and reduced sensor life.
Innovation Solution
The Joystick Electronic System (JSE) employs force sensing in a linear application with multiple springs and automatic calibration, providing variable hold and feedback similar to pilot control joysticks, with features like free play, dead-band, and modulation, and includes redundant sensors for improved accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large electric coils are used to create electromagnetic hold, then the hold force is sufficient, but the device takes up more space, costs more, and generates more heat
Solution Approach 1:
The patent replaces the traditional large electromagnetic coil system with a magnetic hold system using permanent magnets and a magnetic circuit. This substitution eliminates the need for large electric coils while maintaining sufficient hold force, thereby reducing space, cost, and heat generation.
Solution Approach 2:
The patent uses a ratchet mechanism that allows periodic engagement and disengagement of the magnetic hold. The hold is maintained during operation but can be quickly released when needed, providing periodic action that satisfies both holding requirements and space constraints.
2Stability of the object's composition
If notches are added to the coil face to prevent vehicle bump from moving position, then the hold is more stable, but clicking feedback is created that is not smooth and may not be desired
Solution Approach 1:
The patent replaces the notched coil face mechanical solution with a magnetic field-based solution. The magnetic hold provides continuous stabilization without mechanical notches, eliminating clicking feedback while maintaining position stability during vehicle movement.
3Force
If force sensing resistors are configured on torsional springs, then force feedback is provided, but the sensor life is reduced due to misalignment stress
Solution Approach 1:
The patent extracts the force sensing function from the torsional spring configuration and implements it separately using load cells or strain gauges on a rigid structure. This separation eliminates the misalignment stress on sensors while maintaining force feedback capability.
4Force
If pilot control is used to provide desired operation force feedback, then the feedback is accurate, but pilot supply and tank lines are required that take up cab space and add system cost
Solution Approach 1:
The patent replaces the hydraulic pilot control system with an electronic force sensing system using load cells and electronic feedback. This substitution eliminates pilot supply lines and tank requirements, reducing cab space and system complexity while maintaining accurate force feedback through electronic control.
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 JSE offers improved operator feedback and reduced operator fatigue by providing a familiar feel similar to pilot control joysticks, with enhanced accuracy and reliability through automatic calibration and redundant sensing, optimizing vehicle performance and reducing system costs.
Implementation Method 1
an electromagnetic coil positioned to cooperate with the cup to provide a magnetic hold at a predetermined position
Implementation Method 2
a force sensing resistor disposed at an end of the plunger and positioned to be responsive to movement of the control lever in the second direction
Data Source
Figure 1~2
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AI summary
An output signal device and method that provides the operator force feedback similar to a pilot control joystick. These force feedback regions include free play, deadband start of modulation, modulation, fore-warning bumper and hold near max angle. This output signal device may also vary the fore-warning feel and hold positions to be at any angle. This output signal device uses force sensing as the signal and has force slope changes used as auto-calibration of the output signal. This improves signal accuracy and provides a service prognostic signal. The prognostic signal may be used to activate redundant sensor. The variable force feedback may improve operation on rough terrain. The force feedback, may allow more productive operating positions to be learned. This enables productivity and other important job site criteria such as fuel usage to be optimized by interactive communication with this output signal device.