Maarten Steinbuch

The alignment and fixation of multiple single-mode optical fibers to photonic integrated circuits is currently a challenging, expensive and time-consuming task. In this paper, we present a concept for a sub micrometer accurate multi-fiber array where fibers are actively aligned with respect to each other and fixated to a flat carrier using UV-curable adhesive. Adhesives are prone to shrinkage which can disturb the fiber alignment. As a result, especially the fixation process forms the bottleneck in reaching the required alignment and not the alignment process itself. Simulations are performed to investigate the sensitivity of process variables on the adhesive bond geometry which is important for the shrinkage amplitude. Furthermore an experimental setup has been designed and fabricated to measure the shrinkage induced fiber displacement for three selected types of adhesives. The results show a controllable adhesive shrinkage where fibers can be aligned with a position reproducibility of -40 nm which is more than sufficient for the most critical fiber alignment applications. With this concept an important step can be made in enabling sub-micrometer accurate photonic interconnects in a cost effective way which is suitable for automated production.

In this paper, gear ratios of a two-speed transmission system are optimized for an electric passenger car. Quasi static system models, including the vehicle model, the motor, the battery, the transmission system, and drive cycles are established in MATLAB/Simulink at first. Specifically, since the regenerative braking capability of the motor is affected by the SoC of battery and motors torque limitation in real time, the dynamical variation of the regenerative brake efficiency is considered in this study. To obtain the optimal gear ratios, iterations are carried out through Nelder-Mead algorithm under constraints in MATLAB/Simulink. During the optimization process, the motor efficiency is observed along with the drive cycle, and the gear shift strategy is determined based on the vehicle velocity and acceleration demand. Simulation results show that the electric motor works in a relative high efficiency range during the whole drive cycle. The energy economy of the case-study vehicle with the optimized a two-speed transmission is also compared to that of the baseline vehicle with fixed-ratio reduction gear.

With disturbance feedforward compensation (DFC), input disturbances are measured and compensated to cancel the effect of the disturbance. Perfect cancellation is not possible in practice due to the causal nature of DFC, in which the compensation generally comes too late. Therefore, non-perfect plant inversion, controller discretization and sensor dynamics lead to a non-zero residual error. The properties of this residual error are described in the frequency domain using a theoretical framework that is closely related to the design constraints known from filtering theory. It is shown that, like in feedback control systems, performance limitations of DFC systems are described by a waterbed effect. An experimental validation is included to demonstrate the properties of the residual error on an active hard-mounted vibration isolation setup.