A VLSI robotic controller

The Dual Axis Manipulator Element (DAME) project is a research effort aimed at servoloop processing and signal conditioning in a robotic envoirnment. The objective is to build a complete DAME, including extensive software development, to control a pair of servomotors within the joint of a servo-manipulator. Its unique feature and the purpose of this research is the design and implementation of a 64-pin custom designed VLSI chip, the Dual Axis Robotic Controller (DARC). Two other chips, a 28-pin Pulse Width Modulator (PWM), and an alternative, a 40-pin Dual Pulse Width Modulator with Digital Interface (PWM2) are also designed with the use of the standard cell library. This thesis presents a conceptual description of the DAME project and emphasizes its importance as a fundamental building block of an advanced telerobotic system. Strategies adopted in the design, implemention, and testing of DARC are discussed in detail. A new, semi-automated approach, encountered in the design of PWM and PWM2 are discussed. A relative comparison between the standard cell design (PWM and PWM2) and the custom design (DARC) is highlighted.

DARC implements optical decoders, pulse-width modulators, and a coprocessor interface. Fabricated in the 3%mu; SCMOS technology it has the advantages of miniaturization of the servo electronics, very high reliability, and unparalleled precision. It replaces several bulky cables, over 130 SSI/MSI CMOS and TTL circuits, and has a bit resolution far greater than what is available with off-the-shelf components. Novel circuit techniques in implementing DARC increase operating speeds and reduce clock skews and inductive noise.