The Cornell Mobile Robots

The Cornell Robotics and Vision laboratory is home to four mobile robots: Tommy, Lily, Rosemary, and Camel. These robots have been designed with the philosophy that they should be flexibile, modular, and easy to use. Unlike many other mobile robots designed for academic research, these robots have not been designed on an ad-hoc basis to meet the needs of a particular research group or project. Instead, the Cornell Mobots are extremely modular, so that individual components can be added or replaced as the research needs of the robots change.

In addition to hardware modularity, these robots have been designed to incorporate a straightforward programming environment, in Mobot Scheme, as opposed to the traditional choice of C or assembly. In this way, a high-level development environment, such as that found on a UNIX workstation, can be used to design and test code for the mobots. It is only necessary to reprogram at the assembly or C level when modifying low-level drivers for the various components of the mobots.

The four mobots are based on the Motorola 68000 architecture (except for Rosemary, who uses a 68340), and are equipped with i80C196KB-based Cornell Generic Controllers which interface between the 68k and the various modular components. Apart from the sonar sensor controller, all sensors and actuators on the mobots communicate with the CGC, which in turn communicates with the CPU.

Pictorially, the mobot architecture can be represented as so:

The CGC and CPU communicate via a serial line with a simple character-based protocol for controlling the various components. Actuators and sensors communicate with the Generic Controller either via RS-232 serial connections, or via memory-mapped I/O on the GC Bus.

Each mobot is equipped with an array of Poloroid sonar range sensors controlled by a 68HC11-based sonar controller. This controller is designed specifically to interface with a G96-bus controller card, as supported by the Gespak, Inc. 68k boards used by the mobots. Therefore, the sonar controller talks to the CPU directly via the G96 bus, not through the Generic Controller. The effective range of each sensor is about 12cm to a few meters.

Tommy, Lily, and Rosemary each have a B12 synchro-drive wheelbase manufactured by Real World Interfaces, Inc. Camel is equipped with a locally-designed treaded base with more powerful motors, and bumpers in the front and rear. While Camel is markedly less agile than the other mobots, it was designed with large-scale manipulation in mind.

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