Development of a Haptic Backhoe Testbed

A commercial backhoe has been modified for haptic control research at Georgia Tech's Fluid Power and Motion Control Center (FPMC). Electrohydraulic valves and feedback sensors have been retrofitted to the backhoe and interfaced with a haptic joystick through a computerized control system. The resulting system provides force feedback to the hand of the operator as he or she manipulates the bucket with the joystick in Cartesian space. This system has been constructed for use as a platform for ongoing research in the area of haptic controls for the fluid power industry. The work presented herein is divided into seven chapters. The first chapter introduces the haptic backhoe concept and provides some motivation for the project. The second chapter presents the current state of haptics-for-hydraulics research as presented in scientific literature. The third chapter presents kinematic and dynamic modeling of the haptic backhoe components for use both in simulation and control. The fourth chapter presents simulation results from the model derived in the preceeding chapter. The fifth chapter describes the design of the physical system. The sixth chapter presents initial test results of the backhoe moving under closed-loop haptic control. The last chapter describes the current state of the system and suggests several areas for future exploration. It is hoped that the haptic backhoe will continue to serve as a useful research tool for many years into the future.M.S