Effect of constraints and vertical wall interaction on workspace of a quadcopter manipulator system

Abstract

The workspace analysis of a robotic arm coupled to an unmanned aerial vehicle executing close-to-target operations is significant. The workspace of a 3 degree-of-freedom manipulator mounted to the bottom of a quadcopter and having an extended workspace is analyzed in this research, along with a motion planning algorithm. The quadcopter manipulator system comprises a robotic arm attached to the quadcopter’s center of gravity at its bottom. The manipulator has an extended workspace as its end-effector can reach three-dimensional locations above and below the drone’s airframe. The arm’s workspace is determined by system kinematics. Certain factors like downwash from the drone, the robotic arm’s singularity, servo motor stall torques, and mechanical structure limit the arm’s workspace during real-time tasks. A detailed description of these factors and their impact on the arm’s reachable workspace is also provided. Based on these limitations, the motion planning algorithm verifies the viability of a specific arm configuration and, therefore, the feasibility of the task. A concept called the near-wall effect and strategies to limit its influence on aerial robots are presented to comprehend the effect of a wall on the system in tasks involving targets on a compound wall. The proposed research outcomes are evaluated using MATLAB and ROS/Gazebo simulations.