Walking Training Apparatus Friction Compensation Control

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Solution Overview

Problem

The existing walking training apparatus experiences mechanical friction in the wire winding mechanism, leading to discrepancies between the actual and target pulling forces during the leg-idling and leg-standing periods, potentially causing uneven force transitions.

Innovation Solution

The apparatus employs a control method that adjusts the motor driving force by adding or subtracting a friction-reducing force in the wire winding mechanism to match the target pulling force, ensuring smooth transitions between the leg-idling and leg-standing periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the first wire winding mechanism winds or pays out the wire using a motor, then the pulling force can be controlled to assist walking motion, but mechanical friction occurs in the wire winding mechanism causing the actual pulling force to deviate from the target pulling force

Engineering Contradiction:
Improvepulling forceVSAvoidmechanical friction
Core Design Contradiction:
ForceVSLoss of energy

Solution Approach 1:

The control device calculates and applies a friction compensation force in advance based on the rotational direction of the motor. When the motor rotates in the first direction (winding wire), the control device adds a friction compensation force; when rotating in the second direction (paying out wire), it subtracts the friction compensation force. This preliminary compensation ensures the actual pulling force matches the target pulling force throughout the walking training process.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the wire winding mechanism operates without friction compensation, then the control system is simpler, but the actual pulling force becomes smaller than target force during winding and larger than target force during payout

Engineering Contradiction:
Improvecontrol system complexityVSAvoidpulling force accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The control device uses feedback from the motor's rotational direction to dynamically adjust the driving force. By detecting whether the motor is rotating in the first or second direction, the control device automatically applies or removes friction compensation, ensuring accurate pulling force control without requiring complex mechanical friction compensation mechanisms.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If friction compensation is not applied, then the wire winding mechanism operates with constant driving force, but the pulling force does not change smoothly at transition points between leg-idling and leg-standing periods

Engineering Contradiction:
Improveoperation smoothnessVSAvoidforce transition smoothness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control device prepares friction compensation in advance based on the motor's rotational direction before force transitions occur. By proactively adjusting the driving force to account for friction changes during direction reversals, the system ensures smooth force transitions at critical moments when switching between leg-idling and leg-standing periods, preventing abrupt force changes that could disrupt walking training.

Inventive Principle:
Principle #10Preliminary action

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 adjustment enables the actual pulling force to closely match the target force, allowing for smooth changes at the transition points between the two periods, enhancing the walking training experience.

Implementation Method 1

control means for controlling a driving force of a motor of the first wire winding mechanism

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

mechanical friction occurs in the first wire winding mechanism

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3300710B1Walking training apparatus and its control method
Publication Date: 2021.05.26 TOYOTA JIDOSHA KK
  • EP3300710B1 patent drawingFigure 1
  • EP3300710B1 patent drawingFigure 2
  • EP3300710B1 patent drawingFigure 3

AI summary

A walking training apparatus includes a first wire winding mechanism configured to pull a wire connected to a leg upward and forward, and control means. The control means performs at least one of control, in a leg-idling period, so as to make the first wire winding mechanism generate a driving force obtained by adding a second driving force for reducing a loss of the pulling force of the first wire winding mechanism caused by mechanical friction in the first wire winding mechanism to the first driving force, and control, in a leg-standing period, so as to make the first wire winding mechanism generate a driving force obtained by subtracting the second driving force for reducing the loss of the pulling force of the first wire winding mechanism caused by the mechanical friction in the first wire winding mechanism from the first driving force.