Song Jingyan

Adaptive Spacecraft Attitude Tracking Controller Design Based on Similar Skew-symmetric Structure

Abstract This article presents an adaptive attitude tracking controller with external disturbances and unknown inertia parameters. The similar skew-symmetric structure is extended from the autonomous case to the non-autonomous case. The non-autonomous similar skew-symmetric is chosen as the desired structure of the closed loop system for attitude controller design. Based on this structure, a novel adaptive backstepping scheme is proposed to design the attitude controller by taking full advantage of the symmetry and the positive definiteness of the inertia matrix. The attitude tracking precision is enhanced by employing the linear parameterized form of the external disturbance torques. Simulation results demonstrate the effectiveness of the proposed attitude controller.

Task planning and simulation platform for on-orbit service multi-robot system

Autonomous On-orbit Service (OOS) is one of the key issues in aerospace technology nowadays. Since multi-robot system, which consists of several low-cost and simple robots, can work more efficiently and robustly than a single and complicated robot, we consider introducing multi-robot system into autonomous OOS. This paper focuses on the topic of task planning in multi-robot system, and takes advantage of expert system to solve this problem. We develop a new expert system called KICNP-S and a simulation platform called JavaRobot, which can simulate a group of intelligent robots performing OOS corporately. The simulation results show that expert system is competent in solving task planning problem, and we only need to modify the knowledge database when conditions of tasks change. Finally, simulation of a simplified OOS task is presented in which up to 13 robots repair a breakdown satellite.

A dynamic data information management algorithm for multi-database system under WAN

In intelligent transportation system (ITS), it is of great significance to share data among distributed and heterogeneous databases to realized system goal. In this paper a strategy of managing dynamic data information for multi-databases system in ITS under wide-area network (WAN) is proposed. Data directory is introduced to record data information of every database system, and is periodically updated by using alphabetical link for database structure set. Updating message is transferred peer-to-peer to avoid bottle neck at one system. Finally, the paper discusses how to detect the login and logout systems. A demo system based on the presented method is introduced to prove its validity.

H 2 output feedback control for polytopic linear parameter-varying systems

This paper reviews the problem of H2 output feedback control for polytopic linear parameter-varying systems. Either plant or controller is not restricted to be time-invariant. By employing the definition of Quadratic H2 Performance, sufficient conditions in terms of linear matrix inequalities are presented for the existence of the desired controller for the continuous time linear parameter-varying system. The conditions guarantee that the closed-loop system is quadratically stable and with a prescribed H2 attenuation level, which is potentially less conservative than that of some previous results. A numerical example illustrates the effectiveness of the proposed approach.

Mixed H 2 /H ∞ gain scheduled state feedback control for an airborne dispenser pitch-axis autopilot

This paper presents a mixed H2/H∞, state feedback control and its application to airborne dispenser pitch-axis autopilot design. Linear matrix inequality conditions that depend only on the vertices of polytope are given for existence of a stabilizing gain scheduled state feedback for linear parameter-varying system in convex polytopic domain, and the solution of the controller is given. The proposed method has the potential to yield less conservative results where the parameters involved can be measured or estimated online because some additional free variables are introduced to LMIs. The augmented system of airborne dispenser pitch-axis is modeled with mixed sensitivity method, applying the proposed method, good transient performance, good steady performance and good capability of disturbance rejection are readily achieved.

Mixed H 2 /H ∞ filtering for polytopic discrete-time systems with parameter dependent lyapunov functions

This paper reviews the mixed H2/Hinfin filtering problem for linear time-invariant discrete-time systems with polytopic uncertainty. By introducing some additional free variables, a parameter dependent Lyapunov stability condition other than the quadratic stability condition is obtained in a polytopic domain, and then a much less conservative filter design approach is presented via solving some LMIs formulated with correspondence to polytopic vertices.

Study on automatic creating method of public transportation dispatching form based on BP neural network

Public transportation intelligent dispatching system (PTIDS) is the most important subsystem in advanced public transportation system (APTS). In order to realize intelligent dispatching, the dispatcher must determine the headway and dispatching form for a certain transit vehicle. As we know, the headway is relatively stable for some certain time period since the passenger flow changes according to regularity. However, the dispatching form must be determined according to the real time passenger flow. This paper proposes that the principle of automatic creating of a transit vehicles dispatching form for the first time. Then, a new automatic creating method based on BP (backpropagation) neural network is introduced, which can make sure that the dispatching form can be created in a short time. The case study in Line 306 of Changchun, a metropolitan city of China, has proved that the method proposed In this paper is application.