TRC Pan - Tilt - Vergence Unit
Introduction :The need for such a unit arises due to the limitations of the human body towards extremes in temperature. Hazards nuclear radiation is also a threat. Robotic manipulators have been widely used in such environments to perform the required tasks. It is almost impossible to imagine all the possibilities in this kind of operation which leads us to the need for telerobotic operations. The Pan -Tilt - Vergence unit provides invaluable visual feedback to the user.
The purpose of this project is to modify the existing TRC - unit to make it more versatile. The original controller was implemented by the SMC-629 which is a three axis motor controller and amplifier unit based on the National LM629 motor controller I.C., designed for servo control of small D.C. motors with quadrature encoder position feedback. Our aim was to build hardware that would interface the unit with a general purpose PC and implement a simple PD - position control. This gives us the flexibility of implementing our own control at a later stage without having to rebuild the hardware.
Setup:The setup consists of an interface box , linear amplifiers and a PC with a general purpose I/O board :
The interface box consists of a transformer and filter to step down 110V ac. The board has four inverting amplifiers - one for each motor.
The linear amplifiers are used to provide the necessary current to drive the motors.
The PC is a 133MHz Pentium based machine running QNX realtime operating system.
The desired Trajectory was got from a Virtual Reality Helmet.