Graduation Year

2008

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Mechanical Engineering

Major Professor

Rajiv Dubey, Ph.D.

Keywords

Computer vision, Haptics, Robotic control, Scaled teleoperation, Virtual fixtures

Abstract

This dissertation presents a novel concept of a hard real-time telerobotic control system using sensory-based assistive functions combining autonomous control mode, force and motion-based virtual fixtures, and scaled teleoperation. The system has been implemented as a PC-based multithreaded, real-time controller with a haptic user interface and a 6-DoF slave manipulator. A telerobotic system is a system that allows a human to control a manipulator remotely and the human control is combined with computer control. A telerobotic control system with sensor-based assistance capabilities enables the user to make high-level decisions, such as target object selection, and it enables the system to generate trajectories and virtual constraints to be used for autonomous motion or scaled teleoperation.

The design and realization of a telerobotic system with the capabilities of sensing and manipulating objects with haptic feedback, either real or virtual, require utilization of sensor-based assist functions through an efficient real-time control scheme. This dissertation addresses the problem of integrating sensory information and the calculation of sensor-based assist functions (SAF's) in hard real-time using PC-based resources. The SAF's calculations are based on information from a laser range finder, with additional visual feedback from a camera, and haptic measurements for motion assistance and scaling during the approach to a target and while following a desired path. This research compares the performance of the autonomous control mode, force and motion-based virtual fixtures, and scaled teleoperation. The results show that a versatile PC-based real-time telerobotic platform adaptable to a wide range of users and tasks is achievable.

A key aspect is the real-time operation and performance with multithreaded software architecture. This platform can be used for several applications in areas such as rehabilitation engineering and clinical research, surgery, defense, and assistive technology solutions.

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