Steering Input Shaft Coupling for Dual-Mode Force Feedback
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Solution Overview
Problem
Existing steer-by-wire systems lack a steering input device capable of operating in both force input/position feedback mode and position input/force feedback mode, and suffer from motor ripple and inertia issues.
Innovation Solution
A steering input device with an operating element connected to an input shaft, a feedback motor, and two angle sensors, utilizing an elastic element to measure angular displacement and reduce ripple effects, allowing operation in both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque is applied to control an element in steer-by-wire systems, then the operator experiences force feedback corresponding to external forces, but the system requires complex force sensing and actuator control mechanisms
Solution Approach 1:
The patent replaces complex force sensing mechanisms with a simplified approach using a strain gauge to measure torque on the input shaft, and substitutes complex actuator control with a feedback motor that directly applies torque through an elastic element. This mechanical substitution reduces system complexity while maintaining force feedback accuracy.
Solution Approach 2:
The elastic element serves as an intermediary between the feedback motor and the input shaft, mechanically coupling them while allowing the system to measure angular displacement. This intermediary component simplifies the control mechanism by providing a direct mechanical connection that naturally transmits torque and enables accurate feedback without complex sensors.
2Ease of operation
If a feedback motor is used to apply force to the operating element, then position feedback can be provided to the operator, but motor ripple and inertia affect control precision
Solution Approach 1:
The elastic element acts as a mediator between the feedback motor and the input shaft, filtering out motor ripple through its elastic properties. This intermediary component smooths the torque transmission while still allowing accurate measurement of angular displacement, thereby maintaining control precision despite motor imperfections.
Solution Approach 2:
The elastic element provides beforehand cushioning by absorbing motor ripple and inertia effects before they reach the input shaft and operating element. This prior cushioning ensures smooth force application and maintains control precision by pre-compensating for motor imperfections.
3Adaptability or versatility
If two steering wheels are used for driver training with independent control, then both student and instructor can operate the vehicle, but control conflict and confusion occur when both pilots apply inputs simultaneously
Solution Approach 1:
The patent implements feedback by connecting both steering wheels to a common control system through elastic elements, allowing each operator to feel the other's inputs as reaction forces. This feedback mechanism provides clear indication of control status and prevents confusion by making control conflicts physically apparent to both operators, thereby maintaining reliability while enabling dual operator capability.
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
Enables seamless transition between force and position control modes while minimizing motor-induced ripple and inertia, providing accurate feedback and efficient torque application.
Implementation Method 1
an elastic deformation occurs in the elastic element when a torque is applied to one of the shafts
Data Source
AI summary
A steering input device for electronically controlled elements of machines, vehicles, aircraft or ships, includes a manually operable operating element connected to an input shaft, and a feedback motor having an output shaft, wherein a first angle sensor is provided whose output signal indicates the angular position of the output shaft, and a second angle sensor whose output signal indicates the angular position of the input shaft. The motor output shaft is rotatably connected to the input shaft via at least one elastic member so that an elastic deformation occurs in the elastic member when a torque is applied to one of the shafts, and the resulting angular displacement between the two shafts is measured by the two angle sensors.