Nilsson, N. J. (1973). A Hierarchical Robot Planning and Execution System. STANFORD RESEARCH INST MENLO PARK CALIF.
This report describes a robot control program consisting of a hierarchically organized plan generation and execution system. The program is written in QA4 and makes use of several features of that language. The usually sharp distinction between robot plan generation and execution is intentionally blurred in this system in that planning and execution phases occur intermixed at various levels of the hierarchy. The system currently exists as a running program that clearly illustrates the concepts involved; major additions and refinements would be necessary if the system were to be used to control an actual robot device.