Nonlinear instability suppression of closed-loop pilot-vehicle system with rate-limiting actuator based on anti-windup compensation

To solve the flight safety problem caused by nonlinear instabilities（category II pilot induced oscillations, PIOs） of the closed-loop pilot-vehicle system with rate-limiting actuator, the antiwindup（AW） compensation method to avoid category II PIOs is investigated. Firstly, the AW compensation method originally used for controlling input magnitude limited system is introduced, then this method is extended for controlling input rate-limiting system through a circle criterion theorem. Secondly, the establishment of the AW compensator is transformed into the solving of linear matrix inequalities. Finally, an AW compensator establishment algorithm for the closed-loop pilot-vehicle system with the rate-limiting actuator is obtained. The effectiveness of the AW compensation method to avoid category II PIOs is validated by time-domain simulations,and compared with rate-limited feedback（RLF） command rate compensation method. The results show that the AW compensation method can effectively suppress category II PIOs and maintain the nominal performance when the closed-loop pilot-vehicle system is normal. Unlike the command rate compensator which works upon system uninterruptedly, the AW compensation method affects the closed-loop pilot-vehicle system only when the rate-limiting of actuator is activated, so it is a novel PIO avoidance method.

Can the ASHRAE Standard 169 zoning method be applied to country-level energy-efficient building design in China?

In current building thermal climate design zones of China,the zoning indicators only include temperature elements without considering the regional difference of air humidity.Therefore,building thermal design strategies in continental climate zone with low relative humidity and marine climate zone with high relative humidity cannot be distinguished by the current building thermal zoning standards.ASHRAE Standard 169 proposes dual definitions for moisture and thermal climate zones,and this method can be extended to the world,including the so-called“China Climate Zones Map”.However,the moisture climate zoning criterion is unsuitable for China’s climate characteristics after climate analysis and building performance evaluation.In present work,a novel building moisture climate zoning method is proposed.The bioclimatic chart was utilized for extracting the outline of building climate through the Gaussian KDE method.Hence,the building moisture climate was classified,the zoning indicator was obtained,and a country-level climate zones map for China was established.The results indicated that the global information matrix served as a helpful guide and reference for planning at the national level.Annual precipitation could be used as a zoning indicator to accurately reflect the regional differences of building moisture climate in China.The approach can provide new thoughts for improving the climate zoning system in current energy-efficient building design standards of China to assist the ultra-low energy consumption target.