As an important component of the chassis system, the vehicle suspension plays a significant role in vehicle comfort, stability, and safety. In dynamic modeling of a semi-active suspension, traditional method is a complicated process, the actuator force is difficult to solve. In the process of model simplification, the influence of the vehicle-axle and balanced shift quality on the vehicle dynamics is not considered. For this reason, applying the Udwadia–Kalaba approach to dynamic modeling and control for a three-axle semi-active truck suspension can establish a simple and accurate equivalent discrete system. By fixing the displacement and acceleration of the body, the simulation is conducted with real excitations between the road and six wheels, and the actuator control forces of the semi-active suspension are obtained under the constraint by applying the Udwadia–Kalaba approach. The contrast in the analysis results from the Udwadia–Kalaba approach and the traditional Lagrange multiplier method indicate that the Udwadia–Kalaba equation can obtain the semi-active suspension actuator forces without introducing additional Lagrange multipliers and that the actuator forces acquired with the Udwadia–Kalaba approach are equal to those of the traditional Lagrange multiplier method.
A two-stage 3.1-to 10.6-GHz ultrawideband CMOS low-noise amplifier (LNA) is presented. In our design, a parallel resistance-capacitance shunt feedback with a source inductance is proposed to obtain broadband input matching and to reduce the noise level effectively; furthermore, a parallel inductance-capacitance network at drain is drawn to further suppress the noise, and a very low noise level is achieved. The proposed LNA is implemented by the Taiwan Semiconductor Manufacturing Company 0.18-μm CMOS technology. Measured results show that the noise figure is 2.5-4.7 dB from 3.1 to 10.6 GHz, which may be the best result among previous reports in the 0.18-μm CMOS 3.1-to 10.6-GHz ultrawideband LNA. The power gain is 10.9-13.9 dB from 3.1 to 10.6 GHz. The input return loss is below −9.4 dB from 3.1 to 15 GHz. It consumes 14.4 mW from a 1.4-V supply voltage and occupies an area of only 0.46 mm 2 . Index Terms-Broadband, complimentary metal-oxidesemiconductor (CMOS) low-noise amplifier (LNA), feedback, ultrawideband (UWB).
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