Dynamic sensor-based control

Abstract

Robots in industries are often used for repetitive tasks. Their motions rely on precise virtual model of their environment and they are not able to handle changes or unexpected events. This disqualifies them to perform tasks that would require precision in a non controlled environment such as an assembly task in real world. Visual servoing is a well known tool to control the robot using spatial sensors. It includes real world references at control law level. But, visual servoing and more generally sensor-based control schemes provide kinematic control law and do not consider robot dynamics. As consequences, tracking performances are poor and convergence behavior is hardly predictable. In this paper, we proposed a new control scheme considering second order sensor-based control law and robot dynamics. Our main goal is to enable full trajectory tracking in sensor-space. Additionally, the scheme is compatible with priority-ordered task sequencing and it can be also used within a hybrid control scheme where force control is considered. This new control scheme brings the possibility to make easier the robot task definition, dividing a complex positioning task into small easy-manageable ones. Multi-tasks operation has been validated in simulation by using MSC Adams software [1] and where the robot has to perform an engraving task on a surface.