Hybrid Control of the Berkeley Lower Extremity Exoskeleton (BLEEX)

The first functional load-carrying and energetically autonomous exoskeleton was demonstrated at U.C. Berkeley, walking at the average speed of 0.9 m/s (2 mph) while carrying a 34 kg (75 lb) payload. The original BLEEX sensitivity amplification controller, based on positive feedback, was designed to increase the closed loop system sensitivity to its wearer's forces and torques without any direct measurement from the wearer. The controller was successful at allowing natural and unobstructed load support for the pilot. This article presents an improved control scheme we call "mixed" control that adds robustness to changing BLEEX backpack payload. The walking gait cycle is divided into stance control and swing control phases. Position control is used for the BLEEX stance leg (including torso and backpack) and the sensitivity amplification controller is used for the swing leg. The controller is also designed to smoothly transitions between these two schemes as the pilot walk...

• Type: Journal
• Year: 2006
• Where: IJRR
• Authors: Hami Kazerooni, Ryan Steger, Lihua Huang
• Keywords: BLEEX, BLEEX Sensitivity Amplification, IJRR 2006, Sensitivity Amplification Controller