Type of Document	Dissertation
Author	Li, Xiaobo
Author's Email Address	xl03d@fsu.edu
URN	etd-06042009-151430
Title	Modeling And Control Of A Powered Cobot
Degree	Doctor of Philosophy
Department	Mechanical Engineering, Department of
Advisory Committee	Advisor Name Title Carl Moore Committee Chair David Cartes Committee Member Patrick Hollis Committee Member Peter Kalu Committee Member Rodney Roberts Outside Committee Member
Keywords	Virtual Constraint Virtual Inertia Hapitics Human-Robot Interaction Cobot
Date of Defense	2008-12-15
Availability	unrestricted
Abstract Cobots are specially designed robots that use continuously variable transmissions (CVTs) instead of traditional motor driven joints. We believe that cobots are an attractive choice for telerobotic master controllers because they are safe in contact with humans and are able to produce stable high quality virtual surfaces that can constrain the motion of the master to directions suitable for telerobotic task completion. This paper presents the modeling and control of a 3-D powered arm cobot for telerobotic operation. A thorough analysis of kinematics and dynamics is presented. By arranging CVTs in parallel(connected to a common wheel), we get an extra Degree Of Freedom(DOF) in jointspace, which provides more control options. With the additional degree of freedom, a linear speed constraint can be applied. The linear speed constraint decouples the motion(velocity and acceleration) control into two parts: direction of the motion which is controlled by CVTs and magnitude of motion which is controlled by common wheel. A new control strategy, virtual mass control, is developed to facilitate smooth interaction between the user and haptic interface while rendering a virtual mass/inertia. Rendering a mass/inertia if combined with "geometry" "texture"and "hardness" enhances telepresence. Results from experimentation are presented and discussed. Conclusions are made and future work is outlined.
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