Exoskeleton Load Compensation Using Intent-Based Force Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exoskeleton control systems require prior measurement of load mass to function effectively, which is impractical for handling loads of varying masses without user constraint.
Innovation Solution
A method for controlling an exoskeleton actuator that detects the user's intention to manipulate a load, applies an increasing command to cause displacement, records sensor values when movement or intention cessation is detected, and uses these values to estimate the resistive force, allowing force control without pre-entering the load's mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior measurement of load mass is required for exoskeleton control, then control accuracy is improved, but ease of operation deteriorates due to user constraints
Solution Approach 1:
The exoskeleton system automatically detects and estimates the load mass without requiring user input or preliminary measurement operations. The system uses sensors to detect user intention and applies increasing commands to estimate the resistive force, making the system self-configuring and eliminating user constraints.
Solution Approach 2:
The system changes the control parameter from requiring fixed load mass specification to dynamically estimating load mass through sensor feedback. By using increasing commands and detecting movement thresholds, the system adapts the control parameters automatically based on actual load conditions.
2Reliability
If load mass is pre-specified for force control, then control reliability is improved, but adaptability deteriorates for varying masses
Solution Approach 1:
The system implements feedback control by using sensors to detect actuator movement and load response. The recorded sensor values are used to estimate the resistive force, creating a closed-loop system that continuously adapts to varying load masses while maintaining control reliability.
Solution Approach 2:
The system transitions from static load mass specification to dynamic load mass estimation. By applying increasing commands and detecting the point of movement or intention cessation, the system dynamically determines load characteristics in real-time, enabling adaptation to varying masses.
3Measurement precision
If preliminary training is required for intention detection, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system eliminates the need for preliminary user training by using straightforward sensors to detect intention changes. The intention sensor directly detects when the user wants to manipulate the load without requiring the user to learn complex interaction patterns or calibration procedures.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for controlling an actuator (11) connected to a load (50) to be handled, the method comprising the steps of: - detecting an intention to handle the load (50); - applying an increasing command to the actuator (11) until a movement of the actuator (11) is detected; - recording a value reached by the command when an actuator (11) movement is detected; - using the recorded value reached by the command in order to determine an estimate of a resistive force exerted by the load to be handled (50); controlling the actuator by means of a force control law using the estimate of the resistive force exerted by the load to be handled (50) in order to establish commands to be applied to the actuator (11). The invention also relates to a cobot (1) designed to implement this method.