Modelling and control of a small-scale unmanned helicopter

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The dynamical model of a toy helicopter considered as two rigid bodies is deduced using Kane's equation. Another model is presented that considers the helicopter as a single rigid body. It is shown that the response of the rotational dynamics modelled as two rigid bodies is cosine while that modelled as one rigid body is linear. In addition, a flight controller is presented that is based on dynamic inversion and model predictive control (MPC). In order to decrease the online computational effort associated with a conventional model predictive controller, an explicit MPC algorithm is introduced, which converts the online computations to offline computations to solve the real-time problem. Experimental results show that the controller is able to operate in real-time and can closely track the trajectory without overshoot

Compliance control of a cable-suspended aerial manipulator using hierarchical control framework

Aerial robotic manipulation is an emergent trend that poses several challenges. To overcome some of these, the DLR cable-Suspended Aerial Manipulator (SAM) has been envisioned. SAM is composed of a fully actuated multi-rotor anchored to a main carrier through a cable and a KUKA LWR attached below the multi-rotor. This work presents a control method to allow SAM, which is a holonomically constrained system, to perform such interaction tasks using a hierarchical control framework. Within this framework, compliance control of the manipulator end-effector is considered to have the highest priority. The second priority is the control of the oscillations induced by, for example, the motion of the arm or physical contact with the environment. A third priority task is related to the internal motion of the manipulator. The proposed approach is validated through simulations and experiments

Whole-Body Teleoperation and Shared Control of Redundant Robots with Applications to Aerial Manipulation

This paper introduces a passivity-based control framework for multi-task time-delayed bilateral teleoperation and shared control of kinematically-redundant robots. The proposed method can be seen as extension of state-of-the art hierarchical whole-body control as it allows for some of the tasks to be commanded by a remotely-located human operator through a haptic device while the others are autonomously performed. The operator is able to switch among tasks at any time without compromising the stability of the system. To enforce the passivity of the communication channel as well as to dissipate the energy generated by the null-space projectors used to enforce the hierarchy among the tasks, the Time-Domain Passivity Approach (TDPA) is applied. The efficacy of the approach is demonstrated through its application to the DLR Suspended Aerial Manipulator (SAM) in a real telemanipulation scenario with variable time delay, jitter, and package loss