OHT Steering Wheel Dithering for Stiction-Free Branch Switching
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Solution Overview
Problem
The steering wheel of OHT vehicles often becomes immovable due to adherence to the damper, leading to inefficient steering changes, particularly in branching regions where multiple vehicles operate simultaneously, causing potential collisions and delays in cargo transfer.
Innovation Solution
A dithering motion function is applied to the steering wheel by sequentially and repeatedly applying forward and reverse torque, allowing the steering wheel to be moved efficiently and released from an immovable state, thereby ensuring proper steering changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the steering wheel is moved in a specific direction, then the steering change is achieved, but the steering wheel becomes adhered to the damper and becomes immovable
Solution Approach 1:
The patent applies dithering motion (high-frequency small-amplitude vibration) to the steering wheel through the steering wheel driving means. This vibration helps the steering wheel overcome static friction and adhesion to the damper, enabling it to move freely in branching regions without getting stuck, thus resolving the contradiction between ease of operation and reliability
Solution Approach 2:
The patent implements periodic dithering motion before the actual steering operation. This periodic vibration is applied in advance to prevent the steering wheel from adhering to the damper, ensuring reliable steering operation throughout the branching region traversal without continuous vibration, thus balancing ease of operation with reliability
2Speed
If the steering wheel is moved rapidly in branching regions, then collision prevention is improved, but the steering wheel may become adhered to the damper
Solution Approach 1:
The patent applies dithering motion as a preliminary action before the main steering operation. This pre-vibration prepares the steering wheel for rapid movement by preventing adhesion to the damper in advance, allowing the steering wheel to be moved quickly and smoothly through branching regions without getting stuck, thus resolving the contradiction between speed and ease of operation
Solution Approach 2:
The dithering motion uses high-frequency vibration to reduce static friction between the steering wheel and damper. This vibration enables the steering wheel to be moved rapidly without adhesion, achieving both fast steering response and smooth operability throughout the branching region traversal
3Ease of operation
If dithering motion is applied to the steering wheel, then steering wheel movability is improved, but the operation complexity increases
Solution Approach 1:
The steering wheel driving means performs dual functions: it applies dithering motion to prevent adhesion and also executes the main steering operation. This self-service approach integrates the vibration function into the existing steering mechanism without requiring separate dedicated vibration actuators, thus improving ease of operation while minimizing the increase in device complexity
Solution Approach 2:
The steering wheel driving means is designed to perform multiple functions: generating dithering motion for adhesion prevention and executing the primary steering operation. This multi-functionality consolidates control mechanisms, reducing overall system complexity while maintaining improved steering wheel movability through integrated design
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 dithering motion effectively addresses the issue of immovable steering wheels, preventing collisions and maintaining efficient cargo transfer operations in high-traffic branching regions.
Implementation Method 1
a dithering motion function is applied to the steering wheel by sequentially and repeatedly applying forward and reverse torque
Implementation Method 2
applying forward and reverse torque
Data Source
AI summary
Proposed are an OHT vehicle and a method of controlling the operation of the same. More particularly, proposed is a technology in which when a steering change is not performed properly as a steering wheel is adhered to a damper during the operation of a steering unit of an OHT vehicle, a dithering motion function is applied to the steering wheel to enable an efficient steering change of the OHT vehicle.