Xueliang Ding

Bio: Xueliang Ding is an academic researcher from Shanghai Aircraft Design and Research Institute. The author has contributed to research in topics: Moon landing & Terminal guidance. The author has an hindex of 1, co-authored 1 publications receiving 5 citations.

Terminal guidance strategy for a hybrid thrust-tether lunar landing scheme

Abstract: A hybrid thrust-tether lunar landing scheme and its terminal guidance strategy are proposed in this paper, which has potential application in avoiding the dusts aroused by the plume of thrusters. The combined lander is made up of a descent stage and a rover, which are connected by a tethered device. An innovative combination of fuzzy and variable-structure controllers is introduced to guide the terminal landing, which is more robust than some classical guidance laws derived from the linearized dynamics. At the beginning of this phase, the combined lander carries out the targeting guidance law from the height of 250 m to the desired landing site. When the combined lander arrives at the height of about 20 m, the tethered device is triggered to release the rover which is controlled by the tensioning force provided by the motor and windlass. In releasing the rover, the descent stage is required to hover above the lunar surface at a certain height until the rover meets safe landing conditions. After the rover cuts off the tether, the descent stage will be driven by the deputy thrusters as far away from the rover as possible. A typical scenario is implemented numerically to demonstrate the stabilization of the horizontal initial velocity even in nonzero azimuth angle case. To investigate the robustness of the closed-loop guidance law, a Monte-Carlo simulation is performed to create all the scenarios parameterized by the errors in initial position and velocity which is the result of last powered descent phase.

Towards the use of fuzzy logic systems in rotary wing unmanned aerial vehicle: a review

Abstract: In recent times, technological advancement boosts the desire of utilizing the autonomous Unmanned Aerial Vehicle (UAV) in both civil and military sectors. Among various UAVs, the ability of rotary wing UAVs (RUAVs) in vertical take-off and landing, to hover and perform quick maneuvering attract researchers to develop models fully autonomous control framework. The majority of first principle techniques in modeling and controlling RUAV face challenges in incorporating and handling various uncertainties. Recently various fuzzy and neuro-fuzzy based intelligent systems are utilized to enhance the RUAV’s modeling and control performance. However, the majority of these fuzzy systems are based on batch learning methods, have static structure, and cannot adapt to rapidly changing environments. The implication of Evolving Intelligent System based model-free data-driven techniques can be a smart option since they can adapt their structure and parameters to cope with sudden changes in the behavior of RUAVs real-time flight. They work in a single pass learning fashion which is suitable for online real-time deployment. In this paper, state of the art of various fuzzy systems from the basic fuzzy system to evolving fuzzy system, their application in a RUAV namely quadcopter with existing limitations, and possible opportunities are analyzed. Besides, a variety of first principle techniques to control the quadcopter, their impediments, and conceivable solution with recently employed evolving fuzzy controllers are reviewed.

Adaptive Fuzzy Sliding Mode Control for the Probe Soft Landing on the Asteroids with Weak Gravitational Field

Abstract: For the trajectory control of the probe soft landing on the asteroids with weak gravitational field, this paper presents a combined integral sliding mode control with an adaptive fuzzy logic system, named adaptive fuzzy sliding mode control (AFSMC) scheme. Considering the uncertainty of the orbit dynamics model in the small body fixed coordinate system, and the polyhedron modeling uncertainty in the gravitational potential, a fuzzy logic system is adopted to approximate the upper bound of the uncertainties. In addition, a robust control item is introduced to compensate for the approximation error of fuzzy logic system. The designed adaptive law and robust item make the closed-loop control stable and the tracking errors are convergent to zero. The controller not only guarantees the rapidity and accuracy of the desired trajectory tracking, but also enhances the robustness of the control system, improving the dynamic tracking performance for the probe soft landing on asteroids. Finally, the contrastive simulation results are presented to show the feasibility and effectiveness of the proposed control scheme.

Nonlinear Dynamics of a Space Tethered System in the Elliptic Earth-Moon Restricted Three-Body System

Abstract: This paper focuses on nonlinear oscillation of a space tether system connected to the Moon’s surface, elongating along the Earth-Moon line at L1 and L2 sides respectively. The full nonlinea...

Optimal guidance for lunar soft landing with dynamic low-resolution image sequences

Abstract: To relieve the burden of obtaining high-precision lunar surface information during lunar soft landing, a new guidance algorithm based on dynamic low-resolution image sequences is proposed. The integrated procedure of dynamic descent stage considering obstacle-avoiding requirement without the hover measurement is designed, which enables the spacecraft to optimize the final landing site by rolling in orbit. A small number of points are used to obtain the variance, slope and roughness of the field of vision subarea, and the shortest distance spiral search algorithm is used to determine the safest landing point. In order to reduce unnecessary control, an acceptance domain algorithm of alternative landing sites is designed to judge whether or not to accept the change of landing sites in dynamic low-precision image sequences. Assuming that the control acceleration is adjustable, the non-singular fast terminal sliding mode (NFTSM) controller based on terminal attractor is adopted and improved, and the stability of the closed-loop system is also proved. The validity, reliability and effectiveness of the proposed guidance algorithm are verified by numerical simulation on the case with disturbance and large sample data. The results demonstrate that the image information required for stable lunar soft landing is far less than that of the traditional methods, which can greatly reduce the burden of the onboard computer.

An Optimal Explicit Guidance Algorithm for Terminal Descent Phase of Lunar Soft Landing

Abstract: An explicit guidance algorithm for multi-constrained terminal descent phase of lunar soft landing is presented in this paper. A minimum jerk guidance is designed and extended for this purpose to achieve the terminal control and state constraints. The closed form jerk expression, obtained using the minimum jerk guidance is analyzed to obtain an explicit expression for acceleration command, which is the physical control variable for the guidance loop. The guidance formulation ensures the minimum rate of change of acceleration and vertical touchdown of the spacecraft towards a designated landing site with high terminal accuracy. The design features of the proposed guidance law are demonstrated using simulation results.