Rail-Guided Vehicle Sensor Layout for Precise Grid Position Tracking
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Solution Overview
Problem
Existing automated storage and retrieval systems face challenges in precisely tracking and confirming the position of vehicles on a grid structure, leading to potential inaccuracies in navigation and control.
Innovation Solution
A remotely operated vehicle equipped with a sensor arrangement comprising first, second, and third sensors directed downward towards the rails in x-, y-, and intersection directions, respectively, to determine its position, with optional fourth sensors for pre-alerting the remaining distance to the set position, ensuring precise tracking and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional tracking methods are used, then the system is simpler, but position tracking precision deteriorates
Solution Approach 1:
The tracking system is segmented into multiple specialized sensors: first sensors for detecting rail crossings in x-direction, second sensors for y-direction rail crossings, and third sensors for corner detection at intersections. This segmentation allows each sensor type to specialize in specific detection tasks, improving overall position tracking precision while maintaining manageable system complexity through modular sensor functions.
Solution Approach 2:
The patent introduces an intermediary pre-alert system that provides advance notification before the vehicle reaches a set position. This intermediary mechanism allows the control system to prepare for upcoming events (rail crossings, corner detections) in advance, improving response time and positioning accuracy without requiring complex real-time calculations at critical moments.
2Measurement precision
If multiple sensors are added for precise tracking, then position detection accuracy improves, but device complexity increases
Solution Approach 1:
The sensor arrangement is designed with multi-functionality where the same set of first, second, and third sensors serves multiple purposes: detecting rail crossings, identifying corner positions, providing pre-alerts, and confirming set position arrival. This universal sensor system achieves high position detection accuracy without proportionally increasing device complexity, as each sensor contributes to multiple detection functions simultaneously.
Solution Approach 2:
The sensor system performs self-verification through cross-checking multiple detection points. The first and second sensors verify rail crossings independently, while the third sensor at the corner provides redundant confirmation of position. This self-service mechanism enhances detection reliability and accuracy without requiring additional external verification systems, thereby limiting the growth of device complexity.
3Measurement precision
If pre-alert system is implemented, then navigation accuracy improves, but response time increases
Solution Approach 1:
The pre-alert system implements preliminary detection by placing third sensors at corner positions that detect rail crossings before the vehicle actually reaches the set position. This preliminary action provides advance notice to the control system, allowing navigation adjustments to be prepared in advance. The key is that the pre-alert distance is optimized to provide sufficient preparation time without causing excessive delay in the actual stopping response.
Solution Approach 2:
The system employs feedback loops where sensor detections (both immediate and pre-alert) continuously inform the control system of the vehicle's position relative to the set point. The control system adjusts the stopping distance and timing based on this feedback, dynamically optimizing the balance between navigation accuracy and response time. The feedback mechanism allows the system to learn from each detection event and refine its stopping behavior.
Data Source
AI summary
A remotely operated vehicle includes an arrangement to provide a pre-alert and tracking of a position of the vehicle following a travelling route relative to tracks laid out on rails in x-, y-directions on a rail system. The vehicle has first and seconds sets of wheels connected to drives for moving the vehicle in corresponding x-, y-directions on the rail system. The arrangement includes at least one sensor module provided with at least four sensors. A first sensor is directed vertically downwards to detect the rails in the x-direction on the sensor module. A second sensor is directed vertically downwards to detect the rails in the y-direction on the sensor module. A third sensor is positioned on the sensor module to detect a corner of an intersection between the rails in the x-direction and y-direction. A fourth sensor is configured to detect a remaining distance to the arrival of the vehicle at a set position, by detecting the rails in the x direction when travelling in the y direction, and detecting the rail in the y direction when travelling in the x direction. The fourth sensor is placed at a predefined position on the sensor module. A controller is provided on the vehicle to receive the output from at least one of the sensors and to pre-alert the remaining distance of the arrival of the vehicle at the position.