Applied Mechanics and Materials Vol. 643

Abstract: Power system stabilizers (PSS) are usually used in power system plants to damp out power system oscillations. In this paper, coordinated and robust tuning procedures by Hybridization technique are used. This hybridization is based on multiobjective functions using stochastic (GA) methods and deterministic methods (gradient) and even between themselves stochastic methods (GA-SA). To validate the effectiveness of this tuning approach in enhancing the stability of power systems, modal analysis and nonlinear simulations have been carried out on a multimachine power system.

Abstract: The paper solved the task of development of the system of telecontrol by the mobile robot and algorithm of its work which allows automatically considering mutual orientation of a movable camera and the basis of the mobile robot. In this case the operator sets control signals using the image on the monitor. The robot moves in the specified direction with any initial orientation of a movable camera and the basis. Such algorithm was developed, simulated on model and realized as the program module.

Abstract: This paper studies the PID control algorithm of foot-pedal lower limb rehabilitation robot which can be viewed as a single closed-loop DC speed regulating system. It is necessary to ensure the steady state of the system under various types of interference and the setting of PID parameters will take a lot of time and energy. For this reason, GA (Genetic Algorithms) is used to set the PID parameters in this paper, PID parameters optimized by different goal functions are presented. The simulation results show that the GA simplifies the setting of PID parameters, for different goal functions make the system outputs have different characteristics.

Abstract: In most of current implementation scheme of remote control parking lock, fixed encoding chips are widely used. Due to its poor security and limited encoding length, it is easy to invade the system by “copying and retransmitting” “scanning and tracking”. In this paper, a hopping code technology based on non-linear shift register technology is utilized. This scheme ensures that the code sent by the transmitter each time is random, non-repeated and irregular, improving the security and immunity of the parking lock effectively. When the software and hardware of parking lock are designed based on PIC16F690 microcontroller, the security of the whole system has been well verified.

Abstract: In order to reduce the cost of coach collision test in R & D process, coach collision test control system is designed by using automatic driving technology. The pseudo collision vehicles run along the longitudinal center line independently, till collide with fixed obstacles. In the coach, PID control theory is used to design and research the control on speed and turn, then install the controller and the corresponding sensors, which is in accordance with the requirements of impact test technology. The experiment results show that, maximum deviation of the test vehicle longitudinal center line coincidence degree is +125mm and-115mm respectively, the speed is still steady by driving straight to accelerate to the required speed of the collision, the design scheme is feasible.

Abstract: The simulation model of permanent magnet synchronous motor system based on speed sensor-less direct torque control is built by analysing the mathematic model of permanent magnet synchronous motor and the theory of direct torque control in this dissertation, and the system’s speed and position is estimated by calculating the angle of stator flux linkage. MATLAB/Simulink is utilized to simulate the system, and the simulation results are analyzed, with which the simulation result prove the correctness and feasibility of the estimation using in this dissertation and good dynamic response performance of the system.

Abstract: Based on the stator-flux-oriented vector control method, this paper presents the mathematic model and control strategy of the doubly-fed machines. The system is simulated, and the simulation results verify the correctness of the mode¹.

Abstract: Basing on the fact that requirements for shift quality in automatic transmissions have been increasing rapidly necessitates the establishment of a suitable shifting control strategy in order to facilitate smoothness of different processes, this paper introduces a simulation model of an 8-speed automatic transmission for front-drive vehicles with respect to detailed shifting strategies and relative parameters. The transmitted torque of the oncoming shift elements before synchronization point can be reduced by an impact function in order to damp the impact and thus make the gear shifting process more smooth. This paper makes a systematic introduction of the structure of 8AT, theoretical basis of control strategy, the establishment of the simulation model and the comparison between test results and simulation results. The conclusion shows that with an accurate dynamic model, simulation results and test results are neighborhood data, the simulation model can be used to help realizing the ultimate goal of better shift quality with higher efficiency, lower shift loads and improved shifting comfort.

Abstract: Robotic automated fiber placement (Robotic AFP) was a cost-effective and highly innovative approach to produce large and complex composite structures. In order to achieve desired qualities, the tow tension of the process required to becontrolled accurately. Due to the high nonlinearity of the system, such as the large elastic modulus, flexibility and viscosity of the tow, traditional methods failed to work effectively. A fuzzy-adaptive PIDcontroller combining fuzzy logic and adaptive PID together was proposed in this work. Fuzzy logic was able to respond quickly to disturbances without the need for an accurate model and adaptive PID control could eliminate the steady-state error by adapting its parameters to the working conditions. With this method, the tow tension could be precisely regulated thus improved the qualities of the composite structures.