Junyue Tang

A real-time recognition based drilling strategy for lunar exploration

Drilling & coring is considered as an effective way to acquire deep sample on the moon. Since the lunar regolith environment in depth is unknown, sampling drill should be developed to adapt to the undetermined drilling medium on the moon. Once mechanical system of sampling robot was finished, control strategy is a key to realize the high-efficiency drilling process. Since composition of lunar regolith is complicated, its not easy to evaluate all the physical parameters to judge the drilling difficulty level. This paper proposes a novel idea of lunar regolith drillability which is established on the rate of penetration under the given standard terms. Drillability is selected to describe the drilling difficulty level which can be identified online by use of pattern recognition method of SVM. Control algorithm tunes the drilling parameters to adapt to the recognized medium. Experiments are conducted to verify the drillability online recognition based intelligent control strategy can make sampling robot adapt to complicated drilling media.

Real-Time Drilling Strategy for Planetary Sampling: Method and Validation

AbstractDrilling and coring, due to their efficient penetrating and cutting removal characteristics, have been widely applied to planetary sampling and returning missions. In most autonomous planetary drilling, there are not enough prior seismic surveys on sampling sites’ geological information. Sampling drills may encounter uncertain formations of significant differences in mechanical properties. Additionally, given limited orbital resources, sampling drills may have a stuck fault under inappropriate drilling parameters. Hence, it is necessary to develop a real-time drilling strategy that can recognize current drilling conditions effectively and switch to appropriate drilling parameters correspondingly. A concept of planetary regolith drillability based on the rate of penetration (RoP) is proposed to evaluate the difficulty of the drilling process. By classifying different drilling media into several drillability levels, the difficulty level of drilling conditions can be easily acquired. A pattern recogn...

Drilling states monitoring for a planetary drilling & coring testbed (PDCT): Method and design

Drilling & coring has been selected as an effective method of acquiring soil sample in robotic planetary explorations. To avoid serious overload faults, drilling states should be monitored online and be tuned in a reasonable range. Herein, a novel flexible tube coring (FTC) method is adopted in China lunar exploration mission. To verify the proposed FTC method and acquire useful drilling states for online control, a planetary drilling & coring testbed (PDCT) was developed. The flowing states of lunar regolith are accurately acquired by applying a camera to calculate the volume of removed cuttings and by utilizing an ultrasonic sensor into the hollow auger to monitor the state of coring soil. Besides, drilling loads are acquired by a F/T sensor installed at the bottom of soil container. Experiments in one typical lunar regolith simulant show that the designed PDCT can be used to conduct ground tests for optimizing drill tools structure and control strategy.

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.