Program Mobile Robots in Scheme 1

We have implemented a software environment that permits a small mobile robot to be programmed using the Scheme programming languagee3]. The environment supports incremental modiications to running programs and interactive debugging using a distributed read-evaluate-print loop. To ensure that the programming environment consumes a minimum of the robot's scarce on-board resources, it separates the essential on-board run-time system from the development environment, which runs on a separate workstation. The development environment takes advantage of the workstation's large address space and user environment. It is fully detachable, so that the robot can operate autonomously if desired, and can be reat-tached for retrospective analysis of the robot's behavior. To make concurrent applications easier to write, the run-time library provides multitasking and synchronization primitives. Tasks are lightweight and all tasks run in the same address space. Although the programming environment was designed with one particular mobile robot architecture in mind, it is in principle applicable to other embedded systems.