Applied Mechanics and Materials Vols. 719-720

Abstract: This paper discusses the state-of-art of adaptive control approaches for nonlinear systems to date and presents a new classification framework, in which the existing adaptive control approaches can be broadly classified into two categories: model-driven methods and data-driven methods. The principle, main research progress, and inherent problems of these methods are reviewed. Finally, some practical considerations and future directions are also briefly explored and discussed.

Abstract: Quadrotor is a kind of popular unmanned aerial vehicle which obtains prime advantages in simple structure, vertically taking off and landing and hovering ability; hence it possesses wide application prospects in reconnaissance and rescue, geological exploration and video surveillance. However, attitude and position control of the quadrotor are challenging tasks because it is an under-actuated system with strong nonlinear, coupling and model uncertainty characteristics. In this paper, the dynamics model and the state space function of the micro-quadrotor are firstly established. Then, a cascade control scheme is proposed to decouple the control system and a multivariate RBF(Radial Basis Function) neural network control PID algorithm is proposed to realize robust control of the quadrotor. This algorithm is not only characterized by simple structure and easy implementation, but also capable of self-adaption and online learning. Simulation results show that the proposed control algorithm performs well in tracking and under disturbances and model uncertainties.

Abstract: In the paper, a new method is proposed for the hot issues of the fuel-saving of the inland navigation. Firstly, the thought of segmentation is used to construct the model of fuel consumption in the inland navigation, which takes a whole grasp of the voyage. Then, we use the nested adaptive genetic algorithm and sequential quadratic approximation (SQP) method respectively to plan out the optimal distribution of speed in order to reach the lowest fuel consumption. Also, simulation of the two methods were carried out and compared. According to result analysis, the more appropriate sequential quadratic approximation method is selected. Finally, the optimal speed distribution and the lowest fuel consumption is obtained, which is with guiding significance for the sailing crew. More importantly, the method can be applied to any navigation and any ships.

Abstract: Synchronization problem between QCNN (Quantum Cellular Neural Networks) and duffing system was studied in the paper. Not only one new controller with less parameters in QCNN was designed, but it was proved by Lyapunov function that output signal would be convergent to reference signal, and meanwhile, forms of multi-dimension controllers were given. Then the synchronization structure was draw with the corresponding controllers. In the simulation results, the new controller has higher time efficiency, which shows applying the new controller to QCNN is feasible and effective and it can assure the achievement of synchronization. Furthermore, weak periodic signal can be detected in QCNN, which provides one new thought to detection of weak signal.

Abstract: The Scramjet performance of air-breathing hypersonic vehicle is highly correlated with flight height, Mach and angle of attack (AOA). The violent disturbance of the AOA can cause the engine power off. Consequently the maneuverability of hypersonic vehicle is strictly limited in the phase of cruise. A composite Control system for an air-breathing hypersonic vehicle is presented. The hypersonic vehicle has a configuration with tail control rudders and a set of deflectable wings installed nearby the center of gravity. During the phase of cruise, the precision of AOA is achieved by deflecting tail rudders, and the maneuverable acceleration command is tracked by deflecting wings. A linear quadratic (LQ) track control algorithm with integrator is used to design the composite control system. Simulation results demonstrate that the composite control system has good performance in tracking AOA and acceleration command by respective deflection in cruise.

Abstract: Abstract: In order to improve the penetration efficiency of missile, an effective suggestion is fixing jammer in missile. The jamming can decrease the radar detection range of air-defense missile weapon system, so the intercept frequency is lessened. In this paper, it builds the intercept model of ship-to-air missile with radar detection range. Thus, the penetration probability of missile is presented. Finally, the simulation illustrates that the jamming is effective, and the results can provide suggestion on the jammer parameter design.

Abstract: In combustion of a circulating fluidized bed, primary air plays a key role in keeping materials fluidized and regulating bed temperature. This report provides a design of reference governor for primary air fans to amend their control commands. That will improve the combustion efficiency via regulating primary air flow rate timely according to the changes of coal feed flow rate and bed temperature. To deal with the large inertia and slow response feature of primary air fans, a rule-based control method was used to design the reference governor. Based on the experiences of technical experts and operation data analysis, an expert rules system with wide coverage range was developed, which composed of the logical relationships between the coal feed flow rate, bed temperature and the primary air flow rate in various operation conditions. Test results show that designed reference governor can improve the control performance of primary air flow rate obviously.

Abstract: The precise speed and torque controls of Permanent Magnetic Synchronous Motor (PMSM) are usually realized by using speed or position sensor. However, the mounting of speed or position sensor requires an additional space. The cost of motor drive system with speed or position sensor is high, the reliability is low and is difficult to maintain. This paper presents one novel control strategy for PMSM sensorless vector control based on model reference adaption system(MRAS). This control strategy doesn’t need any speed or position sensor and can estimate the rotor speed with a few parameters. In this paper, PMSM itself is selected as reference model, and the mathematical model of PMSM which includes estimated parameter is regarded as adjustable model. The output error of these two models is used to drive the adaption mechanism and the estimated speed is obtained. The simulation results verify the proposed control strategy is effective, it has excellent dynamic and stable responses, the estimated speed precision is high and the system is robust.

Abstract: In view that present traditional composites forming technologies are difficult to guarantee the processing quality of complex components such as components with small curvature radius or with concave-convex surface. this paper used the fiber placement technology, and in order to achieve the single independent and overall joint movement control of each fiber tows ,it adopted the mainstream open control mode of a PC machine combined with a programmable multi-axis motion controller . At the same time, it introduced a feedback system to realize the accurate pressure control of multiple fiber tows, so as to ensure the quality of fiber placement.

Abstract: In this paper, the optimal modified performance of the single-input multiple-output (SIMO) linear time-invariant (LTI) systems is investigated. The performance bound is related to the scaled factor, the inner factor of the plant and the spectral density of the reference signal. The output dimension also plays an important role. The strong restrictions of the directions for the reference signal and the assumption that the plant must have an integrator in the existing conclusions are not necessary. Also the modified performance index overcomes the invalidity when the state error is not zero vectors.