Operator-Assist Device with Force-Regulated Motor Speed
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Solution Overview
Problem
Existing devices for aiding ascent and descent, such as those with a box moving along a fixed link, suffer from constant speed adjustments that do not adapt to the user's weight, leading to jerky movements and potential lifting, and inaccuracies in motor drive measurements due to the link's location far from the operator.
Innovation Solution
Incorporating force measurement means to measure the operator's traction force and control motor speed accordingly, ensuring precise and adaptable movement by positioning measurement means near the motor, and using a drive wheel system with auxiliary wheels to maintain contact and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor means drives the box at constant adjustable speed along the fixed link, then the device can adapt to different weights, but the movement becomes jerky and may lift the operator
Solution Approach 1:
The patent applies dynamics by transitioning from constant speed control to variable speed control. The motor means now adjusts its speed dynamically based on real-time force measurements from the operator's traction, enabling smooth acceleration and deceleration that adapts to the operator's movements and prevents jerky motion and lifting.
Solution Approach 2:
The patent implements feedback by using force measurement means to continuously monitor the operator's traction force on the attachment means. This feedback signal is fed to the control means, which adjusts the motor speed accordingly, creating a closed-loop control system that ensures smooth and safe operation.
2Device complexity
If the measuring means are positioned far from the operator at the motor drive means, then the device structure is simpler, but the measurement accuracy regarding operator behavior is reduced
Solution Approach 1:
The patent uses the attachment means as an intermediary element that connects the operator to the box. The force measurement means are positioned at this intermediary point, allowing accurate measurement of the operator's traction force while maintaining a simple overall structure. This intermediary location provides direct access to the force information without requiring complex positioning.
3Device complexity
If the box moves at fixed speed regardless of operator behavior, then the control system is simpler, but the operator may experience sudden tractive effort or lifting
Solution Approach 1:
The patent implements feedback control where force measurement means continuously monitor the operator's traction force and transmit this information to the control means. The control means then adjusts the motor speed in real-time to prevent sudden tractive effort and lifting, ensuring operator safety while maintaining relatively simple control logic.
Solution Approach 2:
The patent applies preliminary anti-action by using the control means to anticipate and counteract potentially harmful movements. When the force measurement indicates the operator is being lifted or experiencing sudden tractive effort, the control means immediately adjusts the motor speed to prevent these unsafe conditions before they can cause harm.
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 solution provides smooth, flexible movement that adapts to the operator's behavior, preventing lifting and sudden efforts, while ensuring accurate and safe operation with reduced installation dimensions and complexity.
Implementation Method 1
force measurement means able to measure the traction force exerted by the operator on the attachment means
Implementation Method 2
motor means equipped with a speed variator, said motor means carried by said casing being configured for driving the casing in displacement at adjustable speed along said link
Implementation Method 3
motor means equipped with a speed variator... driving the casing in displacement at adjustable speed
Implementation Method 4
using a drive wheel system with auxiliary wheels to maintain contact and stability
Data Source
Figure 1
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AI summary
A device (1) for assisting in the raising and/or lowering of a person, comprising: -a housing (2), -a link (3) capable of passing through said housing (2), said link (3) being provided, at each of the ends of same, with at least one member (4) rigidly connecting it to a support along which the housing (2) needs to be moved, -motor means provided with a variable speed drive and configured to drive the housing (2) in movement along said link (3) at an adjustable speed, -means (6) for hooking said housing (2) to an operator (13). The device comprises force measuring means capable of measuring the traction force exerted by the operator (13) on the hooking means (6), and means for controlling the operation of the motor means at a speed regulated on the basis of at least said measurement.