Applied Mechanics and Materials Vols. 300-301

Abstract: In the present article, we obtained uniform and rather flat melanin films with the dendrites structure using self-assembly technique on Si substrate. The structure of film was confirmed by Fourier-transformed infrared spectrometry (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Experimental results showed that the grown on the Si substrate, self-assembly film had oriented quality. Furthermore, according to the results, a model of the secondary structure in the melanin films was also proposed.

Abstract: In this paper, a novel interpolation algorithm for high speed machining is presented, which integrates S-curve acceleration/deceleration method in look-ahead function. A time division based speed planning method is used to implement discrete S-curve acceleration/deceleration method. The implementation of the proposed algorithm is given out. The proposed algorithm improves the processing efficiency and avoids the shock of machine tools caused by frequent acceleration and deceleration. The experiment shows that the proposed algorithm satisfies the requirements of interpolation accuracy and machining efficiency in high speed machining.

Abstract: In this paper, a compensation method of coupling error used in high-precision turning machine is proposed. The laser interferometer and optical lens are used for measuring coupling error of machine; the precise motion characteristic of the micro-adjusting mechanism is utilized for compensating. In the end, this method is verified by experiments, and the results show that the motion accuracy of the test bench has been effectively improved.

Abstract: An intelligent control strategy is proposed in this paper, which is applied to the high-speed train ATO (Automatic Train Operation) system in the cruise condition. The dynamics of a high-speed train is discussed based on a typical single-point-mass model and the force analysis in cruise state is studied. A fuzzy neural network control algorithm is incorporated into the ATO system aiming at improving the velocity and position tracking performance in the cruise operation of high-speed train. This control scheme adjusts the parameters of membership functions on-line and does not rely on the precise system parameters such as resistance coefficients which are very difficult to measure in practice. The numerical simulation verifies the effectiveness of this fuzzy neural network algorithm.

Abstract: Stopping accuracy is an important index to measure the performance of Automatic Train Operation (ATO), as well as a significant guarantee of the safety of the train’s operation. However, during the process of braking, the stopping accuracy of the urban rail vehicle is affected by the line conditions, brake shoe friction coefficients and random noise. A braking model of the train reflecting these uncertain conditions and principle of braking system is derived in this paper. Based on this model, an adaptive backstepping control scheme is proposed to track ideal braking curve. Using Lyapunov stability theorem, the stability and the convergence of the adaptive algorithms are proved. Simulation results verify that this method not only overcomes the impact of uncertain parameters but also greatly improves the stopping accuracy of the train without loss of the comfort level of passengers.

Abstract: A boost power factor correction (PFC) in continuous conduction mode (CCM) by the digital peak current-mode control method with bifurcation control is discussed in this paper. The proposed method is used to prevent the inductor current bifurcation behavior, which is caused by sub-harmonic oscillation when the duty cycle is upon to 50 percent. The bifurcation behavior will increase the inductor current ripple and dissipation, then reduce the Power Factor (PF). Different from the ramp compensation signal performed with analog IC in some papers, a MCU is used to be the controller and also provides the digital compensation function in this paper. With the timer, ADC, PWM, and comparator which are built in the MCU, the necessary parameters will be measured without extra components and additional cost. The proposed method is based on those parameters. In this paper, the MATLAB/Simulink simulation results show the proposed method workable.

Abstract: This paper introduces a open-source free software package, SCILAB, for teaching a typical post-graduate level robust control course. SCILAB is a useful computational tool that may replace high-cost control design and analysis software such as MATLAB. Although SCILAB has been around for a long time, it seems that there is no tutorial available in literature which demonstrates the use of SCILAB for robust control design and analysis. This paper describes the use of SCILAB for the main topics discussed in a typical post-graduate robust control course, including mixed-sensitivity H-infinity control design, H-infinity loop-shaping design and mu-analysis.

Abstract: A second-order sliding mode control (2-SMC) based on backstepping is proposed to improve the performance of spacecraft control system for the chattering of traditional sliding mode control (SMC) in practical application. Original system is transformed according to 2-SMC theory Then, an appropriate Lyapunov function is select based on designed sliding manifold of the 2-SMC. The simulation results demonstrate that the proposed controller improves the performance with better tracking specifications in the case of external disturbances, better behavior of the output and faster convergence of the sliding surface while maintaining the stability.

Abstract: In the real automated highway system, various factors to vehicles which are moving make the velocity of vehicles change suddenly. In this paper, assuming that the mass of vehicles, the drag coefficient and the resistance of the ground were uncertain, the controller for a class of time-varying delayed look-ahead vehicle longitudinal following system with impulsive effect was designed by using the idea of quasi-sliding mode control. An example is given at last to test the controller proposed in this paper.

Abstract: This study implemented fuzzy control theory with a cerebellar controller to design a fuzzy cerebellar model articulation controller (FCMAC), ensuring system stability by deriving an adaptive FCMAC weight update rule from the Lyapunov theory. The speed estimator design in this study is based on the structure of an adaptive stator flux observer (ASFO) to achieve rapid sensorless control. According to results from experiments, installing the adaptive FCMAC speed controller in the induction motor’s direct torque control system demonstrates excellent speed dynamic response.