Applied Mechanics and Materials Vol. 392

Abstract: Dead Reckoning (DR) is one of the frequently used navigation system for a mobile robot. It provides short term navigation information but its error can accumulate over time without limit. The Global Positioning System (GPS) can be used for localization and navigation outdoors wherein the removal of the SA Policy improved the accuracy of the GPS for civilian use but the error is still quite large. Standard Differential GPS (DGPS) can be used to achieve an error of less than one meter but the costs are prohibitive in terms of commercializing it into the mass market. In this research study, a cheap GPS receiver was used for the navigation system of a mobile robot outdoors in which a new Kalman-filter based DR/GPS data fusion method was utilized. This proposed method is based on the characteristics of the GPS receiver. Fusing the data from the GPS receiver and the DR system provided precise navigation information for the mobile robot. Simulation was performed to check and validate the effectiveness of the proposed fusion method and good results showed its potential for mobile robot navigation outdoors.

Abstract: Planetary power-split hybrid vehicle is a very common structure of hybrid electric vehicle (HEV), which achieves speed and torque double decoupled between engine and wheels. Engine always working on optimal curve is an important reason for low fuel-efficient. Engine speed is controlled by PID, and the optimal loading rate of engine is solved from engine characteristic curves; finally realization of engine working on optimal curve. Offline simulation is used for this algorithm, and comparing with many experimental results demonstrates engine works on operating point; fuel consumption is close to the official fuel consumption of Prius.

Abstract: This paper proposes a gain scheduling approach by neural network to force control of the electric vehicle wheels. To approximate to the reality in simulation, we utilize the traction force database of the motor, called the current-RPM-torque database, instead of the slip ratio measurements. The system is nonlinear and a constant gain cannot overcome all road conditions of the traction force control for the electric vehicles. The appropriate gains for different road conditions can be the training data of the neural network. In this paper, the proper parameters for the RBF neural network are obtained. The appropriate gains which have to fit the assigned specifications in time domain seem to be inverse proportion to the slip ratio slope.

Abstract: As an intelligent system, self-reconfigurable robot is able to change its configuration depending on different environments and tasks. This work illustrates an approach to the study on the process of deformation from chain-type configurations to circular configurations. In this work, the junction surface of module units and coordinate transform matrix are defined. And the general formulas are deduced based on the D-H method and mathematical induction as well. The motion trail, velocity and acceleration of the end docking face during the deformation are simulated by RecurDyn and MATLAB. The simulation results prove the correctness and validity of the general formula. The approach estimates the kinetic trajectory and reconfigurable space.

Abstract: This paper presents a novel docking mechanism, based on a new type of mobile modular self-reconfigurable robot named M²SBot. The paper introduces the design of structure, the principle of work and the feasibility analysis of this mechanism in detail. At last, the simulation of kinematics based on Adams verifies the feasibility of the docking mechanism. The prototype of the mechanism was manufactured by 3D printer.

Abstract: Active magnetic bearings open-loop instability makes the features of dynamic magnetic field crucial to the control performance. We presented a nonlinear calculation of AMBs dynamic magnetic field by FEM. Firstly, we constructed a AMBs dynamic field FEM model considering the magnets nonlinear permeability; Secondly, we applied a harmonic current to the coils through 160 load steps and a zero magnetic potential boundary condition; Finally the field was solved and magnetic flux lines, air gap flux density and eddy current density were retrieved and analyzed. Because of the nonlinearity of eddy current, air gap flux density is not standard harmonic and lags behind the source current,and as magnetizing energy equalizes eddy current losses, air gap flux density approaches harmonic.

Abstract: A DC-excited high torque electromagnetic brake has been designed for high-speed train in WHMFC. An electromagnetic-thermal analysis model for electromagnetic brake analysis has been developed, taking into account the specific heat capacity-temperature relation, nonlinear magnetization-saturation and the skin effect. With simplification, the complex transient electromagnetic-thermal process has been successfully solved. This paper follows a previous work in which analysis was performed with electromagnetic analysis only.

Abstract: This paper presents a new type of the electrical loading system with a large torque. Based on the characteristics of this system, the paper analyses the design of this system from some aspects: the hardware system structure, the host and the guest computer software system structure, method of restraining surplus torque. It is realized by torque and position hybrid control. Through dynamic and static loading test verification, this system has a large torque, high loading frequency, the higher loading precision to meet the testing needs of the domestic high-performance electrical loading system.

Abstract: This paper deals with the design, simulation and implementation of a digital sliding mode controller for brushless DC motor-based electromechanical actuator. Firstly, a mathematic model of the actuator is drawn from its structure. Secondly, sliding mode control algorithm with the approach to weaken chattering is designed for the system, and simulations are carried out under Matlab/Simulink environment. Thirdly, the SMC algorithm is implemented on TMS320F2812 digital signal processor platform along with extensive experiments. Lastly, results of simulation and experiment are compared and discussed, showing that the proposed approach can achieve accurate and fast position tracking in the presence of load disturbance and plant parameter variations.

Abstract: In this paper,the necessity of the coordinated control is further discussed under state-switch based on the analysis of dynamical characteristics of both engine and motor. The thoughts of torque compensation and powertrain sequence are illustrated with detail and used to build up simulation model.The acceleration fluctuation is used to measure the simulation results of the coordinated control strategy, and it is finally manifested by the simulation results which are got through MATLAB/SIMULINK and CRUISE that the coordinated control algorithm can effectively reduce the fluctuation of vehicle acceleration and ensure smooth power transfer under state-switch.