Drive-By-Wire Jogwheel Haptics for Caster Effect and Stability
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Solution Overview
Problem
Drive-by-wire technology for power equipment machines faces challenges in providing effective user feedback and simulating a caster effect, which are crucial for improved drivability and directional stability, especially in outdoor maintenance applications where mechanical linkages are absent.
Innovation Solution
A drive-by-wire steering system that includes a steering interface system with a motor and encoder to provide rotational input and feedback, and a power steering system with steerable wheels and motors, communicating via a communication link to apply torques and simulate a caster effect, enhancing user feedback and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If drive-by-wire technology is used to control power equipment steering, then mechanical linkage complexity is reduced, but directional stability and driver feedback are compromised
Solution Approach 1:
The system implements a feedback mechanism where the steering interface position encoder detects the user's steering input angle, and the steering motor applies resistive torque based on this position feedback. This closed-loop control replicates the feel of mechanical steering while maintaining the benefits of drive-by-wire architecture, thereby improving directional stability without requiring complex mechanical linkages.
Solution Approach 2:
The patent replaces traditional mechanical steering linkages with an electrical drive-by-wire system consisting of a steering interface, position encoder, and steering motor. This substitution eliminates complex mechanical connections while maintaining steering control functionality, reducing overall mechanical complexity in the power equipment.
2Measurement precision
If drive-by-wire steering system is implemented, then control precision is improved, but haptic feedback and drivability are reduced
Solution Approach 1:
The steering interface motor applies resistive torque to the steering interface based on feedback from the position encoder and steering motor position encoder. This haptic feedback mechanism provides the operator with tactile sensation of steering effort and wheel position, improving drivability while maintaining precise electronic control through the encoder systems.
Solution Approach 2:
The steering interface motor generates resistive torque that counteracts the operator's steering input, simulating the natural resistance felt in mechanical steering systems. This counter-torque mechanism provides realistic haptic feedback, making the drive-by-wire system more intuitive and easier to operate despite the absence of direct mechanical connection.
3Ease of operation
If manual steering control is used, then driver feedback is maintained, but automation capability is limited
Solution Approach 1:
The steering system is designed to operate in multiple modes: manual mode where the operator directly controls the steering interface, and autonomous mode where the controller system automatically adjusts the steering motor position based on GPS and map data. The same hardware components serve both manual and automated functions, enabling seamless transition between operation modes while maintaining driver feedback through the haptic interface.
Solution Approach 2:
The position encoders provide continuous feedback about steering interface and motor positions, enabling the control system to monitor and adjust steering in both manual and autonomous modes. This feedback mechanism allows the system to maintain awareness of steering state regardless of operation mode, facilitating smooth transitions between manual and autonomous 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 system improves drivability by providing powered feedback and simulating a caster effect, reducing the risk of oversteering and enhancing directional stability, even in the absence of mechanical linkages, thus improving the operational efficiency of power equipment machines.
Implementation Method 1
a steering interface motor configured to rotate the steering interface; and a steering interface motor controller configured to control activation of the steering interface motor to apply one or more torques to the steering interface
Implementation Method 2
one or more steering motors configured to turn the one or more steerable wheels; one or more steering motor controllers configured to control activation of the one or more steering motors to turn the one or more steerable wheels toward a target wheel angular displacement
Data Source
AI summary
A drive-by-wire steering system for a power equipment device is provided. One example embodiment comprises a steering interface system, a power steering system, and a communication link connecting the steering interface system and power steering system. The power steering system can adjust steering angle of wheels of the power equipment device based on inputs received from the steering interface system. The steering interface system can receive user inputs and provide powered feedback and/or a simulated caster effect via a steering interface. Additional embodiments include power equipment devices and steering interface systems.