The CODGER System for Mobile Robot Navigation

Abstract

Most sophisticated mobile robot systems are large and complex [7, 6]. For this reason, such systems are usually developed by a team of researchers, rather than an individual. Furthermore, in order for these systems to execute in a reasonable amount of time, the computations must be parallelized to some degree. These two characteristics pose two problems:

What software engineering tools are needed for developing a large mobile robot system?

What software support is needed for successfully distributing the computation across a number of processors?

In the case of the Navlab and its development laboratory, the software system consists of five to ten large sensing, planning, control, and graphics modules running on a mixture of Suns and Vaxes interconnected via an EtherNet. Both Lisp and C are available for programming. From a software engineering standpoint, we would like to support module development in multiple languages running on multiple machine architectures, all tied together in a single system. Furthermore, we would like one module programmer to be able to modify or extend one part of the system without requiring redesign or recompilation of the rest of the system. Concerning multiprocessing support, we need a common data format to all modules, regardless of programming language or machine type. We need a mechanism for moving data between modules, and more importantly, synchronizing this exchange. For geometric data, which is used by nearly every module in the system, we must guarantee that it is consistent, so that all modules agree as to the location of the robot and an objects in its environment.