Analysis of computational parallelism with a concurrent hierarchical robot control system

Abstract

Robot control systems require concurrent architectures to overcome real-time constraints. Satisfying real-time constraints is important, but determinism, not performance, is the key element in assessing a control model. The goal of this paper is to present the concurrent hierarchical control model as an efficient, flexible, and deterministic robot control methodology and then systematically analyze the factors affecting the design and performance of a concurrent hierarchical control system. The ability for concurrent hierarchical control to be systematically modeled is derived from the generic software approach to all levels of control. The generic software control primitive of the model is the virtual control loop. A virtual control loop is a software concept analogous to a hardware duty cycle; software cyclically samples commands and status to produce outputs within a bounded response time.