Zoe Doulgeri and Theodora Kastritsi presented the following paper “On the Stability of Robot Kinesthetic Guidance in the Presence of Active Constraints" at 2018 European Control Conference (ECC 18).
Summary of the paper follows:
In recent years, robot-assisted surgery has achieved widespread surgical application, enabling surgeons to perform complex and intricate tasks. The accuracy and precision is limited by the dexterity of the human operator. This implies that the human-robot collaboration can lead to undesired results during surgery, such as serious damage of delicate tissues or organs. A promising solution for this problem is the incorporation of Active Constraint enforcement controllers which ensure that the motion is repelled away from the forbidden and sensitive areas. However, the system’s stability characteristics are so far only partially analyzed usually focusing on system’s passivity with respect to the system velocity output. Is it, however, certain that forbidden areas will never be violated and the behavior will be smooth and predictable?
Their work examines the behavior of such controlled systems incorporating active constraints under the presence of bounded energy human guiding forces. It is found that with active constraints falling within a special class, the safety of delicate tissue is guaranteed while undesirable amplifications of oscillatory guiding force inputs may appear in some cases which should be avoided in surgical applications.