Applied Mechanics and Materials Vol. 742

Abstract: An accurate and fast flowchart of surface-mounted permanent magnet brushless machine (SPMBM) design based on exact analytical method (EAM) rivaling finite element method (FEM) is formally proposed in this paper. It is recognized as a promising expert system for the preliminary electromagnetic design of SPMBM, even to replace the conventional design flowchart using equivalent magnetic circuit method (EMCM). By applying this expert system aiming at the low cogging torque and high power density, a special SPMBM named electronically commutated permanent magnet synchronous DC machine (PMSDCM) with conventional DC armature winding is put forward and verified based on both the simulation and experiment.

Abstract: A new structure magnetorheological brake with three effective areas was designed, two end surfaces and the cylindrical surface of the rotor work as effective areas, then the effective area was increased with the same volume of the rotor. Depending on the characteristics of the magnetorheological brake structure, the finite element model of the magnetorheological brake was built, the electromagnetic field analysis was performed, then magnetic field quantities of the brake model were got. With the results of the magnetic analysis and the relation between the yield stress and the magnetic field strength of the magnetorheological fluid, the performance simulation of the magnetorheological brake was realized. On these bases, the magnetorheological brake and the mechanical performance test system were developed, the mechanical performance of the brake was researched used the test system, the brake’s properties: torque vs. speed and yield torque vs. current were obtained.

Abstract: In the control model of the permanent magnet linear motor (PMLM), if the pneumatic cylinder is used to balance the weight, the pressure dynamic variation of both suction chamber and discharge chamber can affect the load force of model. The dynamic model of pneumatic cylinder is analyzed, and the equation of impedimental force caused by the single acting pneumatic cylinder is given out. With the combination of PMLM model, the system’s kinetics equation is established. A modified 3-tier composite control structure based on nonlinear force observer is put forward. The nonlinear part of the system is compensated effectively. The the experiment results demonstrate the practical applicability and efficiency of the proposed method.

Abstract: A precision compensation method for space manipulator trajectory planning is presented for improving the accuracy during the execution of a task. First, the control process is described by using a state space equation. Second, process parameters are estimated in real-time using particle filter. Then, the system’s real time operational reliability is calculated based on the state space equation and process parameters. Finally, a control variable compensation strategy is given based on the theory of Statistical Process Control. Simulations show that this method effectively improves the accuracy and stability of space manipulator control system.

Abstract: This paper is a survey on research status of the force-feedback master manipulator for teleoperation at home and abroad. The conclusion includes three aspects: mechanism configuration, control strategy and the model of people’s arms. The authors compared different theories already developed. Then they present the strengths and weaknesses of each theory. The conclusion is significant in pointing the direction for future study.

Abstract: This paper focuses on developing a novel control strategy of synchronizer for dual clutch transmission. The synchronization process is investigated and a mathematical model of synchronizer is proposed. The paper proposes a switch control method for synchronizer which is a hybrid dynamical system. The simulation results demonstrate that the performance of the switch controller is reasonable and effective.

Abstract: An accurate mathematic model of permanent magnet synchronous motor (PMSM) is necessary for precise torque control and/or high efficiency drive control. This paper discusses the development model of PMSM by taking all losses and saturation into account. In the proposed model, all losses composing of the copper loss, core loss, mechanical loss and stray loss were analyzed to improve the torque equation. In addition, considering the influence of saturation level, the variations of the core loss resistance, direct-quadrature axis magnetic inductance and permanent magnet flux were discussed on support of the data analyzed by Ansoft. In order to verify the developed model, a start up simulation is performed in the mode of open-loop and the results confirm the validity of the model.

Abstract: Based on the problem that there is a relatively small number of analog simulations on swimming of fish a in specific fluid conducted by science researchers, a simulated tuna model is established in this paper, in which CATIA is used to construct the streamline shape of simulated tuna and the method of computational fluid dynamics is utilized to simulate the swimming of tuna in marine environment. Indexes for fluid performance such as pressure on the surface of robot fish, turbulence kinetic energy and flow velocity of fluid around are focused on, and preliminary research on the variation trend of pressure on the robot fish and of turbulence kinetic energy at different velocities is conducted in this paper. Theoretical analysis and experimental research conducted in this paper may provide some references for design of shape of robot fish in the future.

Abstract: The conventional PD controller could cause the saturation problem of ballistic missile actuators. A design method of anti-windup variable parameter PD controller was proposed. The proportional coefficient and derivative coefficient were designed to be Gauss functions of system tracking error. Both were small when tracking error was big; whereas both increased as the tracking error decreased. This method not only restrained effectively the saturation problem, but also produced enough control force to drive system outputs to track their commands speedily. The control effect of anti-windup variable parameter PD controller was compared with that of the conventional PD controller in the numerical simulation. The simulation results show that the anti-windup variable parameter PD controller has better control effect.

Abstract: As the expanding applications of linear ultrasonic motor, the demand for high-thrust linear ultrasonic motor in the aerospace and industrial robots is growing. Consequently, for a high-thrust linear motor, it’s stator model was established according to the actual structure of the motor stator and was also analyzed of the motor stator modal by the finite element method. The results show that the inherent frequency of vibration for the motor stator increases with the order, and corresponds with the vibration mode, by which was realized to work for the linear ultrasonic motor.