If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -This paper aims to present a robust design approach to realize disturbance attenuation for a yaw -pitch gimballed system subject to actuator saturation and disturbances. Design/methodology/approach -To minimize the impacts of disturbances in the presence of saturation nonlinearity and acquire desired response performance, the control approach is of double closed-loop configuration. State feedback controllers are synthesized via convex optimization and used to stabilize the inner loops; robust controllers are synthesized via mixed H ϱ optimization and used to stabilize the outer loops. Findings -It is shown through performance simulations that the proposed control scheme is effective in terms of command following, stability and disturbance attenuation. Practical implications -The presented robust control approach provides a theoretical method to facilitate designing a stable servo control loop for a yaw -pitch gimballed seeker. Originality/value -This paper supplies an effective way of addressing stabilization problem induced from actuator saturation and system uncertainties.

Disturbances induced from platform motion, gimbal imbalance and state couplings, may severely degrade the line-of-sight tracking accuracy of a two-axis gimbaled system and even induce instability. This article intends to present a stable approach to realize optimal disturbance attenuation for a yaw-pitch gimbaled system, in the presence of saturation nonlinearity and multiple disturbances. A dynamic model of the line-of-sight dynamics is formulated and linearized; feedback controllers are synthesized via linear matrix inequalities and convex optimization; state trajectories of the system before and after stabilization are compared to examine the effectiveness of the feedback approach. The simulation results show that the synthesized controllers are effective in stabilizing the system and realizing optimal disturbance attenuation.

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The two-axis gimbaled antenna's performance can be greatly improved if it is statically balanced. This paper intends to present a novel design of a measurement system for use in statically balancing a two-axis gimbaled antenna mounted on an aircraft. The details of the measurement system and its working principle are explained, including the dynamics of the two-degree-of-freedom flexure-hinge leverage and the control configuration of the measurement system. The measurement principle is proposed after the theoretical measurement uncertainties estimated and the key factors that determine the measurement accuracy are found. By controlling the uncertainty induced from the major factors, the measurement accuracy can be finally controlled. The measurement result is proved sufficiently accurate by means of High-speed centrifuge method.

Background Although the association between inadequate or excessive gestational weight gain (GWG) and adverse pregnancy outcomes has been investigated in China, most studies use the Institute of Medicine (IOM) guidelines, which might not be suitable for Chinese women characteristics. Besides, studies exploring association between GWG in the second trimester and pregnancy outcomes are relatively few. Methods A total of 976 cases of live-birth singleton pregnancies at the Shanghai General Hospital were included in this retrospective observational study. Patients were classified into three groups including GWG during 24 gestational weeks (G24WG) within, below and above the Standard of Recommendation for Weight Gain during Pregnancy Period published by Maternal and Child Health Standards Professional Committee of National Health Commission (NHC), China PR in 2022 (2022 Chinese GWG guidelines), which specifies the recommended value of weight gain of natural singleton pregnancy in China. Binary logistic regression was used to estimate the adjusted odds ratio (OR) and 95% confidence intervals (CIs) of adverse pregnancy outcomes among three G24WG groups. Results Of the 976 women analyzed, 12.6% had G24WG below the 2022 Chinese GWG guidelines, while 37.2% had G24WG above the 2022 Chinese GWG guidelines. Women with G24WG below the 2022 Chinese GWG guidelines had a higher risk of Small for Gestational Age (SGA, Adjusted OR = 2.690, 95% CI: 1.334–5.427, P = 0.006) and a lower risk of Large for Gestational Age (LGA, Adjusted OR = 0.435, 95% CI: 0.228–0.829, P = 0.011) than women who had G24WG within the 2022 Chinese GWG guidelines. Conclusions G24WG is a strong predictor of newborn anthropometric outcomes and help doctors provide appropriate nutritional counseling for pregnant women in China.