Papers by Author: Qiang Zhang

Abstract: We propose a new concept design about carbon-free vacuum cleaner. The carbon-free vacuum cleaner moves under the act of external forces instead of the motor, and transmits the rotation speed from low to the ideal speed with the gear up box. In order to to verify the reasonableness of the gear up mechanism and weather the designing of the gears meet the demand, we construct the detail assemble model of the gear up mechanism based on pro/e software, and then analyze the gear with the finite element analysis method.

Abstract: On-orbit servicing technology is a novel aerospace technology, which has important economic and military value. Reference to two on-orbit servicing programs named Orbital Express and Phoenix, the paper provides visual modeling and on-orbit module replacement simulation approach for a type of spacecraft based on satellite tool kit (STK). A kind of universal method for STK model building is presented, which includes multi-software model transformation and manual encoding. Some key problems about model integration and post processing, that helps complex STK model building, has also been summarized. An on-orbit replacement task simulation system based on co-simulation of MATLAB and STK can provide effective technical support for the aerospace program.

Abstract: The main problems for Genetic Algorithm (GA) to deal with the complex layout design of satellite module lie in easily trapping into local optimality and large amount of consuming time. To solve these problems, the Bee Evolutionary Genetic Algorithm (BEGA) and the adaptive genetic algorithm (AGA) are introduced. The crossover operation of BEGA algorithm effectively reinforces the information exploitation of the genetic algorithm, and introducing random individuals in BEGA enhance the exploration capability and avoid the premature convergence of BEGA. These two features enable to accelerate the evolution of the algorithm and maintain excellent solutions. At the same time, AGA is adopted to improve the crossover and mutation probability, which enhances the escaping capability from local optimal solution. Finally, satellite module layout design based on Adaptive Bee Evolutionary Genetic Algorithm (ABEGA) is proposed. Numerical experiments of the satellite module layout optimization show that: ABEGA outperforms SGA and AGA in terms of the overall layout scheme, enveloping circle radius, the moment of inertia and success rate.

Abstract: The interference and collision detection problem among objects is widely studied in graphics, simulation, animation and virtual reality technologic. In this paper, we proceed from the main solution for collision detection, analyzed from graphic space, bounding volume hierarchies (BVH), Particle Swarm Optimization (PSO) and parallel algorithm, summarized the research situation about collision detection in recent years. At last, we give several suggestions to improve the efficiency and reliability of the collision detection algorithm.

Abstract: Based on multi-objective generic algorithms, a novel approach to optimizing control parameters for large angle spacecraft attitude was proposed. The large angle attitude maneuver controller was designed by taking the spacecraft nonlinear dynamics model and Lyapunov method. To optimize the controller parameters, the alterable weight coefficient method was adopted. Optimal value of time and power consumption acted as fitness goals of the algorithm. Simulation results showed that the algorithm proposed in this paper was superior to the traditional single-objective optimization design method.

Abstract: By analyzing the key indicators which contain the value of the target spacecrafts, the attrition of servicing spacecrafts and consumption of time and fuel, a mathematical model is formulated. And a hybrid discrete particle swarm optimization (HDPSO) algorithm is proposed. Simulation results show that the algorithm can efficiently solve the multi-spacecrafts task allocation problem under multiple constraints.

Abstract: Based on the growing on-orbit servicing technology, replaceable techniques have been proposed agenda. Replaceable plug body is designed for such demand. On the basis of the structural design of the plug body, the kinetic analysis of the mechanism is made in ADAMS to test the feasibility of the structure. Establish Euler-Lagrange equations of the system to determine the impact of total energy of connecting rod on the mechanism, make great analysis to ensure that there is no coupling phenomenon, and optimize the design parameters.

Abstract: In this paper, we propose a novel algorithm for facial recognition based on features fusion in support vector machine (SVM). First, some local features and global features from pre-processed face images are obtained. The global features are obtained by making use of singular value decomposition (SVD). At the same time, the local features are obtained by utilizing principal component analysis (PCA) to extract the principal Gabor features. Finally, the feature vectors which are fused with global and local features are used to train SVM to realize the face expression recognition, and the computer simulation illustrates the effectivity of this method on the JAFFE database.

Abstract: AES is one of the most widely used cryptographic systems. DNA computing has the high efficiency to solve some NP-problems. Therefore many scientists try to combine DNA computing with cryptography. In this paper, an algorithm is designed to simulate a plaintext encrypted by DNA biotechnology and modern cryptography. After mapping the plaintext information as DNA chain and handling the base chain with biological genetic technology, we can get the gene codes form, then using the Rijndael algorithm to deal with the biological chain with cryptography and get the final result. It makes the DNA-based cryptography more effective and more security.