Longitudinal control of an intelligent vehicle using particle swarm optimization based sliding mode control

This paper focuses on the design of longitudinal controller for an intelligent vehicle which was built at Asian Institute of Technology based on sliding mode control. The proposed controller uses particle swarm optimization (PSO) for optimal tuning of sliding surface and controller gain in the sliding mode controller (SMC). The longitudinal control is conducted via controlling of throttle value angle using PSO-based SMC on the simplified first-order linear model of the intelligent vehicle and controlling of brake force using fuzzy logic. In order to achieve the desired headway time, integration of throttle valve angle control and brake force control is required. To obtain the optimal parameters of SMC, two equations velocity updating and position updating are applied. Firstly, the performance of proposed controller is evaluated by using MATLAB simulation to compare with conventional PD controller. Finally, the experimental results show that the proposed PSO-based SMC can perform efficiently in longitudinal control of the intelligent vehicle.     

In situ monitoring of the growth of Cu(In,Ga)Se2 thin films

Thin films of Cu(In,Ga)Se₂ were grown by co-evaporation process in a conventional vacuum coating system at the base pressure of 10⁻⁵ mbar. The controllable of the two-stage growth process was developed. During the growth process, substrate temperature, graphite heater temperature, heating output power and temperature of the CIGS surface were monitored simultaneously. In this setup, we use the change in the thermal behavior of the substrate due to the variations in emissivity of CIGS film during the transition of Cu-rich to Cu-poor in the second stage corresponding to the change of power fed into the substrate heater as the control signal. By observing the variation of control signals, the desired final composition of the film can be obtained. Using our device fabrication, Al/ZnO(Al)/CdS/CIGS/Mo/SLG solar cells with efficiency over 14% (without AR) were achieved.