Four-Way Shuttle Absolute Positioning on Perpendicular Rails
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Solution Overview
Problem
Existing automated warehouse systems face inaccuracies in vehicle positioning due to wheel wear, vibrations, slippage, and power failures, particularly in four-way shuttles operating on perpendicular track systems, which rely on encoder-based position feedback that is unreliable.
Innovation Solution
Implement an absolute positioning system using optically readable data representations, such as bar codes or data matrices, fixed along perpendicular rails to provide precise vehicle location data, readable by onboard optical readers, ensuring accurate positioning independent of vehicle-dependent sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encoder-based position feedback systems are used to track vehicle position, then the system can provide continuous position data, but positioning accuracy deteriorates due to wheel wear, vibrations, slippage, and power failures
Solution Approach 1:
The patent replaces the mechanical encoder-based position feedback system with an optical positioning system. Optical readers mounted on the vehicle read absolute position data from optically readable representations (barcodes or data matrices) fixed to the rails. This substitution eliminates dependence on wheel rotation measurements, thereby resolving the contradiction between continuous position data provision and positioning accuracy maintained under various operational conditions.
Solution Approach 2:
The patent introduces optically readable representations (barcodes or data matrices) as an intermediary medium between the vehicle and the positioning system. These representations are fixed to the rails and contain absolute position information that the vehicle's optical readers can read. This intermediary provides a reliable reference that is independent of the vehicle's mechanical components, resolving the contradiction by providing continuous position data through an external reference rather than through wheel-based measurement.
2Ease of operation
If encoder-based position feedback is used, then vehicle movement can be controlled, but positioning accuracy is compromised by wheel wear and slippage
Solution Approach 1:
The patent replaces the mechanical wheel-based encoder system with an optical reading system. The optical readers mounted on the vehicle read absolute position data from optically readable representations fixed to the rails. This substitution maintains ease of vehicle control while eliminating positioning errors caused by wheel wear and slippage, as the position data comes from a fixed external reference rather than from wheel rotation measurements.
3Ease of manufacture
If manual vehicle movements occur during servicing without propulsion system control, then maintenance operations can be performed, but positioning errors and uncertainties occur
Solution Approach 1:
The patent introduces optically readable representations fixed to the rails as an external reference system that remains valid regardless of how the vehicle moves. Whether the vehicle moves under propulsion control or is manually moved during maintenance, the optical readers can always read the absolute position data from the fixed representations. This intermediary reference system ensures positioning reliability is maintained even when the propulsion system is not controlling the vehicle.
4Duration of action of stationary object
If traditional encoder-based feedback systems are used, then vehicle positioning can be tracked continuously, but the system is vulnerable to power failures and manual movements
Solution Approach 1:
The patent replaces the encoder-based system that requires continuous power and control signals with an optical system that reads absolute position data from fixed representations. The optically readable representations contain absolute position information that does not require power to maintain. The optical readers can acquire position data at any time by reading the fixed representations, providing continuous positioning capability that is robust against power failures and independent of propulsion system control state.
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
Enhances positioning accuracy and reliability by using an external, fixed reference system, reducing errors and optimizing cargo handling operations in automated warehouses.
Implementation Method 1
First and second optical readers, mounted on board each vehicle, are configured to read respectively the first and second data representations along respective mutually perpendicular rails
Data Source
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AI summary
An automated warehouse having pairs of parallel first rails (11a, 11b) and pairs of parallel second rails (12a, 12b), perpendicular to the first rails, and one or more four-way vehicles (10) is provided. Along the first and second rails are arranged respective optically readable representations (15, 24) of position data that univocally identify the absolute positions of points, within the automated warehouse, and along the first and second rails (11a, 11b), where the optically readable representations of position data are placed. A first (16) optical reader and a second (25) optical reader are mounted on board of the four-way vehicle (10). The optical readers are configured to read the first (15) and second (optically readable representations of position data, respectively, along respective first and second rails (11, 12) perpendicular to each other.