Safe Control of Robotic Manipulators in Dynamic Contexts

Abstract

The intended goal of this thesis is to bring new insights for developing robotic systems capable of safely sharing their workspace with human-operators. Within this context, the presented work focuses on the control problem. The following questions are tackled:-for reactive control laws, i.e., control problems where the task to be performed is not known in advance but discovered on-line, how is it possible to guarantee for every time-step the existence of a solution to the control problem? This solution should allow the robot to accomplish at best its prescribed task and at the same time to strictly comply with existing constraints, among which, constraints related to the physical limitations of its actuators and joints.-How to integrate the human-operator in the control loop of the robot so that physical contact can safely be engaged and de-engaged? Regarding the first point, our work arises as the continuity of previous results developed by Sébastien Rubrecht during his PhD thesis. Sébastien Rubrecht introduced the concept of constraints incompatibility for robots reactively controlled at the kinematic-level. The problem of constraints incompatibility appears for example when the formulation of the constraint on an articular position of a robot does not account for the amount of deceleration producible by its actuator. In such case, if the articular position constraint is activated tardively, the system may not have sufficient time to cope with the imposed joint position limit considering its bounded dynamic capabilities.