Door Speed Control via Entry Detection
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Solution Overview
Problem
In industrial settings with operable doors and robots, there is a risk of workers being caught in the door, as existing systems lack effective mechanisms to prevent such incidents.
Innovation Solution
A system that includes a door controller, a door drive part, and an entry detection mechanism to decrease the door's speed and torque when a person is detected within the robot's motion range, using sensors and switches to define a safety zone and adjust the door's operation accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the door moves at high speed to improve productivity, then the door closing time is reduced, but the risk of catching a person increases
Solution Approach 1:
The door control system dynamically adjusts the door's movement speed based on real-time detection of persons in the danger zone. When a person is detected by the entry detection part, the door controller automatically reduces the door speed to a safe level. When no person is detected, the door operates at normal high speed, thus resolving the contradiction between productivity and safety.
Solution Approach 2:
The system implements a feedback mechanism where the entry detection part continuously monitors the danger zone and provides real-time information to the door controller. The controller adjusts the door speed based on this feedback signal, creating a closed-loop control system that automatically balances productivity and safety requirements.
2Productivity
If the door moves at high speed to maintain productivity, then the processing efficiency is improved, but the safety risk increases
Solution Approach 1:
The entry detection part is positioned to detect persons before they enter the critical danger zone where the robot operates. The system takes preliminary action by detecting potential hazards in advance and preparing the door controller to reduce speed, preventing the safety issue before it can occur while maintaining normal high-speed operation otherwise.
Solution Approach 2:
The door controller acts as an intermediary between the high-speed door drive mechanism and the safety requirements. It receives detection signals from the entry detection part and mediates the door's movement by adjusting speed commands, thus protecting the system against safety risks while maintaining productivity.
3Reliability
If a complex detection system is added to detect person entry, then the safety is improved, but the device complexity increases
Solution Approach 1:
The entry detection part is extracted as a separate, dedicated component with a specific function of detecting person entry into the danger zone. This modular approach simplifies the overall system design by separating the detection function from the door control and robot control functions, making each component simpler and more focused while collectively achieving high safety reliability.
Solution Approach 2:
The system replaces complex mechanical safety interlocks and physical barriers with electronic/optical detection mechanisms. The entry detection part uses sensors (such as optical sensors or proximity sensors) to detect person entry, substituting mechanical detection methods with more sophisticated but ultimately simpler electronic systems that require fewer moving parts and maintenance.
Data Source
AI summary
A system which can reliably prevent a worker from being caught in a door which is provided on a work machine. The system comprises a work machine which has an operable door, a door drive part which makes the door operate, a door controller which controls the door drive part, a robot which is provided so that at least part can enter and retract from the inside of the work machine when opening the door, and an entry detection part which detects a possibility of a person entering a predetermined zone which includes a range of operation of the robot. The door controller changes a command value to the door drive part which determines the speed of movement of the door when the entry detection part detects that possibility to a second command value which makes the speed of movement decrease.