In this research, a novel design of a lightweight aerial manipulator system is proposed for solar panel cleaning with active (CoG) compensation mechanism. Recently, separate solar panel arrays or units are commonly installed on residential, commercial rooftops or roads, making it inconvenient for land robots to perform the cleaning tasks. The proposed light weight solar panel cleaning aerial manipulator with the gravity compensation mechanism is intended to be attached beneath a drone to increase its stability during operation. The manipulator workspace given the proposed system is analyzed under CoG shift constraints. The kinematics and dynamics of the aerial manipulator coupled with the compensation mechanism are presented, and a path-planning scheme for solar panel cleaning is detailed. A dynamic control law based on pitch and counterweight position reduced-order dynamics is derived, and its equivalence to the static compensation law is shown. An experimental test bench is used to simulate the aerial manipulation during operations to validate the performance of the proposed manipulator and its stability. Its tilting pitch angle is collected and examined during operation. The results show that the system is less susceptible to unwanted tilting. A tilt angle reduction of 2 degrees was observed between an uncompensated and compensated system, with a difference in shift of CoG location of 1.72% of the total system length. The CoG location shift is also simulated without the presence of a slider mechanism and shows a difference of 24.5% with the compensated system. The compensation mechanism significantly reduces the tilt angle, avoiding potential instability, and consequently decreases the power required by the carrying drone.
30 October 2012 in Journal of Dynamic Systems, Measurement, and Control
Dynamics modeling is becoming more and more important in the development and control of unmanned aerial vehicles (UAV). An accurate model of a vehicle requires good knowledge of the dynamics properties and motion states, which are usually estimated with the help of integrated inertial measurement units (IMUs). This work develops a special six degrees of freedom IMU, which has the capability of measuring the angular accelerations. This paper introduces the design of the new IMU along with its sensor models and calibration procedures. The work introduces two experimental methods to verify the calibrated IMU readings. The IMU was designed to support an on-line methodology to estimate the parameters of UAV’s dynamics model that is currently being developed by the authors.