Helicopter Lands on Uneven Terrain by means of Articulated Robotic Legs-Modelling, Simulation and Control Approach

Abstract

In this paper, a robotic landing gear for helicopters is proposed to replace the conventional fixed skid and a mathematical model is used to investigate into a control strategy for landing on irregular terrains. The landing gear consists of four articulated legs connected to the helicopter fuselage. Each leg has two revolute joints governed by PID joint controllers to generate motion with two degrees of freedom (DoF). A combination of Lagrange and Newton-Euler techniques is used to model the system dynamics, its motion and joint torques. A contact model is introduced to simulate ground interaction forces and a level controller that uses a PI algorithm to maintain the main body desired attitude when landing in two-axes slopes. Simulation results are compared to a second model designed using the SimMechanics toolbox for validation purpose.