Pingping Xue

Research on the adhesion characteristic of climbing robot feet with bionic gecko microarray for spacecraft based on DEM

At present, the robot arm technology occupies the dominant position in the space payload control field. However, with the limitations of robot arm technology, the load control technology with higher flexibility and mobility came into being. The space miniature climbing robot performs on-orbit control tasks such as fault repair and waste removal by crawling through the robotic arm and adhering to the target spacecraft. In this paper, the adhesion characteristic of space climbing robot is studied, an adhesion microarray structure is proposed, and the influence of the contact area, slenderness ratio, length, diameter and density of the microarray on the adhesion characteristics in the zero - gravity environment is analyzed respectively by using the discrete element software EDEM. Results show that: 1) Increasing the density of array with no fibers tangling each other, can obtain the larger adhesion. 2) In order to obtain a larger tangential adhesion, the fiber diameter should be increased and the length be reduced, while in the actual environment, the length/diameter ratio should be appropriately increased because limitation of adaptability to the surface.

Study on the dynamic characteristics of a hammer-driven-type penetrators in the penetration process

Dynamic penetration test by a penetrator is an important detection method for lunar exploration. The analysis of the dynamic penetration properties of the penetrator significantly helps to design the penetrator structure. In this article, the dynamic penetration mechanical model was established according to soil mechanics. Then, the discrete-element simulation model, which was established using the application program interfaces of the EDEM software, was used to simulate the penetration process. The penetration experiment demonstrated the accuracy of the dynamic penetration model and the discrete-element simulation model. This study of dynamic penetration model of a penetrator may provide technical support to the deep space exploration.

Coordinated motion control model of a six-wheeled rocker lunar rover

At present, control methods of the six-wheeled rocker lunar rover primarily consist of setting the same driving parameters for each wheel. This type of control method ignores the multiple active driving characteristics of the lunar rover and causes parasitic power loss. The main cause of the parasitic power loss is the uncoordinated motion of the driving elements. Therefore, in this article, a coordinated motion programming model of the six-wheeled rocker lunar rover based on the velocity projection theorem, the quasi-static mechanical model, and the rated power of the motor is established to eliminate parasitic loss, reduce driving energy, and improve energy efficiency. The analytical solution of the programming model based on the Kuhn–Tucker condition is also calculated. The coordinated motion control model saves energy, and it is suitable for other wheeled-type planet rovers. This model provides technical support for reducing the energy consumption of planet rovers.

Study on electrostatic adhesion mechanism of lunar dust based on DEM

Lunar dust grains threaten the safety of lunar lander and astronauts, because of adhesion. In order to reduce their threat, electrostatic adhesion mechanism and adhesive mechanics model of lunar dust are studied by using Discrete Element Method, Finite Element Method and Image Method in this paper. An electrostatic adhesive mechanics model is derived with electrostatic field theory and verified based on the adhesive force plug-in which is developed by applying the API function on the software platform of EDEM. The model and corresponding simulated adhesive force values can provide a theoretical support for attempts on reducing lunar dust contamination.

Simulation and research on landing impact between lander and lunar regolith based on DEM

Landing-impact between lander and lunar regolith is the decisive factor to soft landing and relates directly to the safety of detection equipment. In this paper, the landing-impact process and the interaction between lander and regolith is researched using the discrete element simulation. Firstly, the landing-impact model is established based on discrete element theory and the mechanical properties of lunar regolith. Many simulations in different working conditions are conducted to study the vertical impact. Secondly, to study the process of landing-impact, dynamic response, stress distribution and motion in a certain condition are studied and the phenomenon of landing impact is explained. Finally, the influence of velocity and mass on the landing-impact is summarized through contrastive analysis. The research in this paper provides reference for the design of lander buffering mechanism and the establishment of the theoretical model.

Study on charging mechanism model of lunar dust for technology of particle removal from detector

In order to reduce the destruction of lunar dust electrostatic adhesion on detector and related equipment, technology of particle removal and charging model are researched. The technology of photoelectric dedusting is proposed. According to the particle orbit theory, current of photoelectron and electron are respectively obtained. Based on Maxwell energy distribution, the density distribution function of each particle is obtained. Then, charging model of lunar dust is setup. The model is solved by Runge-Kutta Method and charging regulation of lunar dust is obtained. Based on charging model, electrostatic adhesion force of nanoscale particles is got by discrete element software. At last, effect of solar radiation intensity on electrostatic adhesion is researched by discrete element software.