Human arm control has been subject to extensive research for many years. It is customary to describe human arm movement using a model of a robot manipulator with rotary joints. In this article we address the characteristics of a controlled robotic arm that approximates human arm movement in very basic operations, such as stabilization and point-to-point control, under conditions of uncertainty. We discuss some structural properties of the robotic arm that may be useful when the mechanical system serves as an analogue model of the human arm. The analysis presented in this article may be relevant and useful to systems supporting people with disabilities, and to robotic surgery systems in which strict regulation and high performance are required. In essence we present an efficient design approach for control systems that need to function in confined spaces under conditions of uncertainty, a common situation in medical procedures performed using robotic systems.