A control engineering perspective on the advantages of efference copies

Abstract

Biological systems have evolved to perform high-speed voluntary movements whilst maintaining robustness and stability. This paper examines a control architecture based on the principles of efference copies found in insect sensorimotor control which we call the inner-outer loop (IOL) controller. Within a control engineering framework, we benchmark the advantages of this control architecture against two common engineering control schemes: a pure feedback (PFB) and a two-degree-of-freedom (2DoF) controller. Our results show that the architecture performs particularly well for systems with noisy sensors, and systems with time-delays. We explain a hypothesis that the structure of the insect sensorimotor system allows the sensors to increase their operating range. Finally, we explore the robustness of the IOL controller and show that it achieves this increased performance with equal stability margins and stability robustness. Finally, we discuss the benefits of the IOL controller in relation to the properties of sensors employed in insect sensorimotor control.