On vibration suppression for the rotor arms of Mars quadcopter based on collision damping

Compared with the “Ingenuity” Mars helicopter with a coaxial rotor configuration designed by NASA, the Mars quadcopter has better folding performance, resulting in a smaller volume when folded. Due to the significant reduction in thrust generated by the rotors in the thin Martian atmosphere, the quadcopter needs to be extremely lightweight so that the thrust generated by the rotors can overcome the gravity of the quadcopter. While the lightweight design reduces the mass of the quadcopter, it also leads to a decrease in the stiffness of the rotor arm. As a result, when the rotational frequency of the rotor falls within the range of the first-order natural frequency of the arm, resonance occurs, causing the quadcopter to become incapable of flight. To suppress the resonance of the rotor arms this paper establishes a simplified model of the lateral vibration of the arm under the excitation of rotor rotation. A method for suppressing resonance of arm based on the collision damping is proposed, which saves on the mass cost of the rotor arms. Three balanced plates with different stiffnesses are employed to verify that the rotor arm after vibration reduction design can reduce the maximum velocity by 83% and the maximum displacement by 81.1% when crossing the resonance region compared with the original arm. The verification of the proposed method of suppressing resonance for the arm in the simulated Martian atmospheric environment.