Rocking Seat Control to Prevent Dislocation in Relaxation Chairs
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Solution Overview
Problem
Conventional relaxation apparatuses cause discomfort due to the front part of the seat portion lowering below the rear part during larger rocking amplitudes, leading to user dislocation and reduced relaxing effect.
Innovation Solution
A relaxation apparatus with a body-supporting unit and a controller that maintains the front part of the seat portion's upper surface level with or higher than the rear part during rocking, incorporating a sunken area and controlling rocking speed near turnover positions to prevent dislocation and ensure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amplitude of rocking motion is increased to provide a more relaxing effect, then the relaxing effect is improved, but the front part of the seat portion lowers below the rear part causing user dislocation and discomfort
Solution Approach 1:
The patent applies dynamics by making the seat portion angle variable during rocking motion. The seat-portion angle is dynamically adjusted to be larger during rocking motion than at the stop position, which maintains the front part of the seat portion at or above the level of the rear part even during large amplitude rocking. This dynamic adjustment prevents user dislocation while allowing effective relaxing motion.
Solution Approach 2:
The controller changes the seat-portion angle parameter during rocking motion to resolve the contradiction. By increasing the seat-portion angle during motion compared to the stop position, the system maintains proper user positioning while enabling larger rocking amplitudes for better relaxation效果.
2Reliability
If the rocking motion speed is increased to enhance relaxation, then the relaxing effect is improved, but inertial forces increase causing user discomfort
Solution Approach 1:
The patent applies periodic action by controlling the rocking unit to vary the speed during the rocking cycle. The speed is made slower as the turnover positions are approached, creating a periodic speed variation pattern. This reduces peak inertial forces while maintaining the overall relaxing rhythm of the motion.
Solution Approach 2:
The controller applies preliminary anti-action by slowing down the rocking motion before reaching the turnover positions. This anticipatory speed reduction prevents excessive inertial forces from acting on the user during direction changes, while still maintaining effective rocking motion for relaxation.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
A relaxation apparatus (10) includes a body-supporting unit (13) for supporting a user's body, a rocking unit (12) for rocking the body-supporting unit back and forth and a controller (24) for controlling the rocking unit to rock the body-supporting unit. The body-supporting unit is provided with a seat (30) portion for supporting the hip and thigh of the user. The controller controls the rocking unit to perform a rocking motion within a range that a level of a front part of an upper surface of the seat portion is kept always equal to or higher than that of a rear part of the upper surface during the rocking motion.