Design and experimental verification of propulsion system for a Mars quadcopter

Due to the Mars rotorcraft can conduct extensive surface exploration of Mars and carry sampler for collecting samples on the Martian surface, it is gradually becoming the mainstream exploration devices for Mars missions. In response to the thin atmosphere on Mars, with the flight duration and sample-carrying capacity of the quadcopter as constraints, we design the propulsion system parameters for the Mars quadcopter with the function of sampling on the Martian surface. A method for evaluating rotor performance indicators, including mass and Mach number at the tip of the blade, is proposed. Based on the evaluation index and the steady RANS method for predicting the lift and drag characteristics of the rotor, an appropriate rotor diameter for the Mars quadrotor is selected. The method combining NSGA-II and two-dimensional steady RANS is employed to optimize the airfoil of the Mars quadcopter blade under the condition of a chord length of 40 mm, a Mach number of 0.43, an angle of attack of 20 degrees, and a Reynolds number based on chord of 6080. Experimental verification for the lift-to-drag characteristics of the single rotor is conducted in an environment simulating the atmospheric density on the Martian surface. The results show that the blade after optimization can generate a thrust of 5.95 N and consume power of 164.9 W, at the rotational speed of 3650 r/min. Based on the test bench with the function of sliding up and down for testing aerodynamic performance of quadcopter, the temperature of the motor and battery discharge characteristics of the Mars quadcopter are conducted. The results of the test show that the quadrotor can provide a thrust-to-weight ratio of 1.66 for the Mars quadcopter while meeting the design requirement of 3 min.