Terrain Feature Estimation Method for a Lower Limb Exoskeleton Using Kinematic Analysis and Center of Pressure.

Area of Science:

• Robotics
• Biomechanics
• Human-Computer Interaction

Background:

• Controlling lower limb exoskeletons requires understanding walking terrain for safety and performance.
• Existing methods may lack adaptability to varied and unknown environments.

Purpose of the Study:

• To develop and validate a method for estimating terrain slope and elevation using exoskeleton ground contact points.
• To enable lower limb exoskeletons to adaptively assist walking on diverse terrains without prior information.

Main Methods:

• Utilized the center of pressure as the ground contact point.
• Calculated contact point locations via kinematic analysis of the exoskeleton.
• Modeled terrain surface using a least-squares plane fit to contact points per step.
• Estimated terrain features by comparing normal vectors of modeled planes.

Main Results:

• Experimental validation on level ground, stairs, and ramps demonstrated accurate terrain estimation.
• Classification based on estimated features achieved over 95% recognition accuracy for all tested motions.
• The method effectively analyzed exoskeleton movement on various terrains without prior environmental data.

Conclusions:

• The proposed method accurately estimates walking terrain features using exoskeleton-ground interactions.
• This approach enhances the capability of lower limb exoskeletons for adaptive and safe assistance in complex environments.
• Enables proactive control strategies for exoskeletons across diverse terrains.