A hybrid pose / wrench control framework for quadrotor helicopters

This paper presents a hybrid pose / wrench control framework for quadrotor helicopters, allowing direct contact of the quadrotor with its environment and stable motion while in contact. The presented work explicitly takes into account the quadrotor´s underactuation and utilizes a wrench estimator, able to estimate the wrench generated by the quadrotor using only quadrotor inputs and pose measurements. Experimental results of the quadrotor in pose and hybrid pose-wrench control mode are presented, showing stable behaviour while moving in contact. Whereas a lot of research nowadays is focused mainly on free-flight applications, stable and robust wrench control of quadrotors in direct contact with their environment, opens up new application areas for this class of flying robots.