Dynamic modeling and analysis of rotating mechanism in planetary soil drilling sampler

It is presented in this paper that a novel planetary soil drilling sampler which can be used on the surface of the Luna, the Mars and some other planets to drill deeply in the soil. The rotary and axial movement of driller in the sampler is generated by the rotating mechanism and feeding mechanism respectively. For the sake of achieving adequate driving ability and security of rotating mechanism, a detailed dynamic model is established by using the lumped parameter method in comprehensive consideration of flexible and nonlinear factors to acquire the motor moment and moments in the mechanism when the sampler is on duty. Because of the uncertainty of load moment on the driller, five typical load functions are constructed in this work to simulate the actual load and to solve the dynamic model. These functions contain constant value function, Gaussian stochastic function, step function, impulse function and time-increasing function. The analysis shows that impact can be aroused in the motor and transmissions of rotating mechanism on the moment of setup or load mutation, while the stochastic variation of load moment can make motor moment and moments in the mechanism fluctuate more seriously. The analysis results could provide theoretical basis for the design of driving ability and security of rotating mechanism in drilling sampler.