Worker Posture Detection for Machine Safety
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Solution Overview
Problem
Conventional safety devices for machine presses face challenges in preventing worker accidents while maintaining working efficiency, as existing entry detection sensors often lead to late stoppage of the machine, resulting in decreased efficiency and increased safety risks due to the need for wider detection areas.
Innovation Solution
A safety device that utilizes a posture obtainment unit to gather data on a worker's lower body posture and a preparatory movement determination unit to identify shifts in the worker's center of gravity away from the machine's working area, allowing for early detection of preparatory movements preceding dangerous actions, thereby enabling timely intervention to prevent accidents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional entry detection sensors are used to detect worker entry into dangerous area, then safety detection capability is provided, but the detection area must be widened which causes late stoppage of the machine and decreases working efficiency
Solution Approach 1:
The system detects preparatory movements (shifting center of gravity away from working area) that occur before the worker actually enters the dangerous area. By identifying these preliminary actions through posture data from pressure-sensitive sheets, the machine can stop earlier than conventional sensors allow, resolving the contradiction between early detection and working efficiency
Solution Approach 2:
Instead of detecting worker position in the horizontal plane (conventional sensor approach), the system detects vertical pressure distribution changes on the floor. This dimensional shift from horizontal position detection to vertical pressure detection enables earlier identification of preparatory movements without requiring wider detection areas
2Reliability
If the detection area is widened to ensure early detection, then safety is improved, but the machine stoppage occurs later reducing productivity
Solution Approach 1:
The system identifies preparatory movements that occur before the worker actually approaches the dangerous area. By detecting the shift in center of gravity through pressure distribution changes on the floor, the system triggers machine stoppage at an earlier time point, preventing both safety incidents and unnecessary production delays
Data Source
AI summary
A safety device for a machine having an action part for processing or moving an object includes: a posture obtainment unit configured to obtain a plurality of posture data indicating a posture of at least part of the lower body of a worker; and a preparatory movement determination unit configured to determine that a preparatory movement preceding a dangerous movement which brings at least part of the upper body of the worker closer to a working area of the action part is being performed in the case where a change in the posture indicated by the plurality of posture data shows that the worker is shifting a center of gravity of whole body of the worker in an orientation away from the working area of the action part without changing positions of both feet.