Overhead Carriage Height Sensor Using Non-Contact Pin Detection
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Solution Overview
Problem
Existing overhead traveling carriage systems face challenges in accurately determining the position of load ports without installing marks and are affected by platform vibrations, leading to inaccuracies in horizontal plane position measurement.
Innovation Solution
The system employs a teaching unit with a height sensor using a pin on the load port, which includes a non-contact magnetic coupling or capacitance variation to determine height and a horizontal plane position sensor using CCD cameras to measure the pin's position, compensating for vibrations by averaging multiple measurements over the platform's vibration period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a contact type height sensor is used to determine the height position of the load port, then the height measurement is simple and direct, but the friction between the pin and the height sensor causes the platform to be stopped at a position offset from the one immediately below the overhead travelling carriage main body, reducing the accuracy of horizontal plane position detection
Solution Approach 1:
The patent replaces the contact-type mechanical height sensor with a non-contact type height sensor that detects the pin's position through magnetic coupling or capacitance variation. This substitution eliminates friction between the sensor and pin, preventing platform displacement and ensuring accurate horizontal plane position detection while maintaining simple height measurement functionality.
Solution Approach 2:
The patent introduces an intermediary detection mechanism where the non-contact height sensor detects the pin's position through its magnetic or capacitive field without direct physical contact. This intermediary field-based interaction allows height measurement while avoiding the mechanical friction that would otherwise cause positioning errors.
2Ease of operation
If the platform is lowered to teach the load port position using marks, then the teaching process is established, but marks must be installed on the load port which increases preparation work
Solution Approach 1:
The patent enables the load port pins to serve dual purposes: their original function for positioning articles and an additional function as detection targets for the non-contact height sensor. This self-service approach eliminates the need for separate marks or additional components on the load port, reducing preparation work while maintaining the teaching capability.
Solution Approach 2:
The patent makes the existing pins on the load port multi-functional by using them both for their original purpose of positioning articles and as detection targets for the non-contact height sensor and horizontal plane position sensor. This universality eliminates the need for separate teaching marks, simplifying the overall system preparation.
3Productivity
If the horizontal plane position is determined during platform vibration, then the measurement can be taken continuously, but the vibration causes inaccurate position measurements
Solution Approach 1:
The patent implements periodic measurement sampling during platform vibration, taking multiple horizontal plane position measurements at different vibration phases and compiling statistics (such as averaging) to determine the final position. This periodic sampling approach allows continuous operation while compensating for vibration-induced measurement errors.
Solution Approach 2:
The patent uses feedback by taking multiple measurements during the vibration period and using statistical compilation to determine the accurate horizontal plane position. The system processes the series of measurements to compensate for vibration effects, providing accurate positioning despite continuous platform movement.
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
This approach allows for accurate determination of load port positions without additional markings and minimizes the impact of platform vibrations, ensuring precise horizontal plane positioning and simplifying preparations by using existing pins on the load port.
Implementation Method 1
The height sensor may utilize magnetic coupling to the pin
Implementation Method 2
a variation in capacitance to detect the pin in a non-contact manner
Data Source
AI summary
A height sensor 26 and an image recognizing section 28 are installed in a teaching unit 24; the height sensor 26 contacts a pin 30a on a load port 4 to detect the height position of the pin 30a and the image recognizing section 28 recognizes a pin 30c and thus its horizontal plane position. A platform 16 of an overhead travelling carriage 8 grips and lowers the teaching unit 24 toward the load port 4. The height sensor 26 then detects the height of the load port 4. Then, the teaching unit 24 is slightly raised. The horizontal plane position of the pin 30c is recognized and averaged over a time equal to at least the vibration period of the platform 16. As a result, the position of the load port can be accurately taught to the overhead travelling carriage 8 without preparations such as the installation of marks on the load port.