ARK-2: A Mobile Robot that Navigates Autonomously in an Industrial Environment

Abstract

ARK-2 is a robot that uses a vision system based on a camera and spot laser rangefinder mounted on a pan and tilt unit for navigation. This vision system recognizes known landmarks and computes its position relative to them, thus bounding the error in its position. The vision system is also used to find known gauges, given their approximate locations, and takes readings from them. "Approximate" in this context means the same sort of accuracy that a human would need: "down aisle 3 on the right" suffices. ARK-2 is also equipped with the FAD (Floor Anomaly Detector) which is based on the NRC (National Research Council of Canada) BIRIS (Bi-IRIS) sensor, and keeps ARK-2 from falling into open drains or trying to negotiate large cables or pipes on the floor. ARK-2 has also been equipped with a variety of application sensors for security and safety patrol applications. Radiation sensors are used to produce contour maps of radiation levels. In order to detect fires, environmental changes and intruders, ARK-2 is equipped with smoke, temperature, humidity and gas sensors, scanning ultraviolet and infrared detectors and a microwave motion detector. In order to support autonomous, untethered operation for hours at a time, ARK-2 also has onboard systems for power, sonar-based obstacle detection, computation and communications. The project uses a UNIX environment for software development, with the onboard SPARC processor appearing as just another workstation on the LAN. Software modules include the hardware drivers, path planning, navigation, emergency stop, obstacle mapping and status monitoring. ARK-2 may also be controlled from a ROBCAD simulation.