Abstract: The soil and rock sampling mission of planetoids far from the earth is a special topic. The soil samples in different depths should be analyzed in place and the data should be transmitted back to us. A multi-function sampler is presented to fulfill the requirements with carefully design, including the design of the drilling system, the sampling system and the heating system, and the soil and rock sampling, volume measuring and heating functions. The constraints of the drill string are changing during the drilling process, so a dynamic buckling model for the drill string is established. The frequency of the drill string is discussed as it is also affected by the changing constraints. By using the ANSYS model, the frequency band is obtained. The coupled sealing force and switch contact force are calculated to determine the reliable driving torque of the actuator. A prototype is established and the functions of the sampler are verified. The sampler is demonstrated as a light weight, low power consumption, multiple functions and large sampling capacity system.

Key words: frequency analysis, mechanical design, planetoid, sampler