Carrying Cart Merging Control via Optical Handshake
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Solution Overview
Problem
Existing conveyance control systems for carrying carts in semiconductor manufacturing facilities face challenges in safely and efficiently managing merging points without increasing facility costs or causing wireless interference, as they rely on radio waves that can lead to erroneous detections and high facility costs due to the need for area sensors.
Innovation Solution
A conveyance control device with a merging point adjacent area entering detection control unit, an obstacle detection unit, and a wireless communication unit that uses a common frequency band and identification code, allowing for local wireless communications and prioritized merging point passing after a successful handshake between carrying carts, thereby preventing collisions and reducing wireless interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radio waves are used for detecting other carrying carts at merging points, then communication between carts is enabled, but erroneous detections occur and facility costs increase due to the need for area sensors
Solution Approach 1:
The patent replaces the radio wave-based detection system with an optical detection system using light receivers and light emitters. This substitution eliminates the need for complex area sensors and reduces erroneous detections by providing more precise optical signaling between carrying carts at merging points.
Solution Approach 2:
The patent uses optical signals (light) as a copy or alternative representation of the radio wave communication method. By transmitting detection information through light instead of radio waves, the system achieves more reliable detection without requiring expensive area sensor infrastructure.
2Productivity
If multiple carrying carts travel on the same route at high speed, then wafer carrier conveyance efficiency is improved, but collision risk at merging points increases
Solution Approach 1:
The patent implements preliminary detection by detecting the presence of other carrying carts at merging points before entering. The light receiver detects light from approaching carts, and the control unit prevents entry until the merging point is clear, ensuring safe high-speed operation without collisions.
Solution Approach 2:
The system uses feedback from light receivers to continuously monitor the merging point status. When light from another cart is detected, the control unit receives this feedback and adjusts the cart's movement to prevent collision, enabling safe high-speed conveyance.
3Measurement precision
If detection members are arranged on the upstream side of merging points, then other carrying carts can be detected, but wireless interference and facility costs increase
Solution Approach 1:
The patent replaces radio wave-based detection with optical detection using light emitters and light receivers positioned at merging points. This substitution eliminates wireless interference while maintaining precise detection capability, as optical signals do not interfere with each other like radio waves do.
Data Source
AI summary
A conveyance control device executes: a control step of detecting entering to a merging point adjacent area set on adjacent to each merging point on the conveyance route; a detection step of detecting whether there is an obstacle around the carrying cart; a communication step of performing, when the entering to each merging point adjacent area is detected, local wireless communications with another carrying cart by using a common frequency band and a common identification code set to values different among merging points; and a merging point passing control step of starting the communication step when the other carrying cart is detected in the merging point adjacent area in the detection step, and causing passing of a merging point in accordance with a priority set to each entering passage to the merging point, after a handshake with the other carrying cart is successfully performed in the communication step.