Adaptive nonsingular sliding mode based guidance law with terminal angular constraint

He, Shaoming,Lin, Defu The Korean Society for Aeronautical and Space Scie 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

In this paper, a new adaptive nonsingular terminal sliding mode control theory based impact angle guidance law for intercepting maneuvering targets was documented. In the design procedure, a new adaptive law for target acceleration bound estimation was presented, which allowed the proposed guidance law to be used without the requirement of the information on the target maneuvering profiles. With the aid of Lyapunov stability criteria, the finite-time convergent characteristics of the line-of-sight angle and its derivative were proven in theory. Numerical simulations were also performed under various conditions to demonstrate the effectiveness of the proposed guidance law.

Robust Output Feedback Tracking Control for a Class of Perturbed Systems Using NDOB and Nonlinear Continuous Predictive Control

Shaoming He,Defu Lin 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.2

This paper presents a new robust output feedback tracking control scheme for a class of higher-orderuncertain systems. Since traditional nonlinear continuous predictive control requires accurate system model aswell as full system states to synthesize a controller, a composite control methodology is adopted in the proposedscheme. Specifically, the nonlinear disturbance observer (NDOB) is used to estimate the lumped uncertainty andthe unmeasured system states in an integrated manner while the nonlinear continuous predictive control regulatesthe system states to track the desired reference signal asymptotically. Detailed stability analysis is also presentedfor the closed-loop nonlinear observer-controller structure through two steps. Then, the obtained results are appliedto missile autopilot design to track the desired angle-of-attack signal. Finally, numerical simulations with somecomparisons are provided to demonstrate the effectiveness of the proposed formulation.

Adaptive nonsingular sliding mode based guidance law with terminal angular constraint

Shaoming He,Defu Lin 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

In this paper, a new adaptive nonsingular terminal sliding mode control theory based impact angle guidance law for intercepting maneuvering targets was documented. In the design procedure, a new adaptive law for target acceleration bound estimation was presented, which allowed the proposed guidance law to be used without the requirement of the information on the target maneuvering profiles. With the aid of Lyapunov stability criteria, the finite-time convergent characteristics of the line-of-sight angle and its derivative were proven in theory. Numerical simulations were also performed under various conditions to demonstrate the effectiveness of the proposed guidance law.

Investigation on Physical Meaning of Three-loop Autopilot

이창훈,Shaoming He,Ju-Hyeon Hong 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.11

This paper aims to reveal the hidden physical meaning or the working principle of the three-loop autopilot. First, the minimal control structure that ensures the desired dynamic characteristics is analyzed. The results show that the three-loop autopilot has a redundant feedback loop from the minimal control structure standpoint. Based on this observation, its physical meaning is interpreted by utilizing the closed-loop tracking error dynamics in the presence of aerodynamic uncertainties. It turns out that the three-loop autopilot has the minimal control structure with an additional command which is based on the instantaneous direct model reference adaptive control. A clear mechanism of how the aerodynamic uncertainties are compensated is provided in the three-loop autopilot. Finally, numerical simulations are performed to validate our findings. The analysis results in this paper show the beauty of the three-loop autopilot: it can be considered as the most concise form to achieve desired dynamic characteristics and counteract model uncertainties. The potential importance of the results obtained is that they allow us toproperly design the three-loop autopilot by reflecting its physical meaning and have potential directions to improve the performance of the three-loop autopilot as well as the adaptive control.

Analytical Study on the Ground Settlement Induced by Pipe-roof Tunnelling Considering the Interaction between Socketed Pipes

Junzuo He,Shaoming Liao,Yong Tan,Mengbo Liu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1

Pipe-roof Pre-construction Method (PPM) is a pre-reinforcement method widely adopted in shallow large section tunnelling in the urban area. As one of the key indexes needed to be controlled, ground surface settlement and axis deviations induced by pipe-roof tunnelling attract increasing attention, but the interaction between socketed pipes (ISP), including shielding and constraint effects, has been lack of consideration in practice. By incorporating deformation coefficient and deviation coefficients, this paper proposed a new analytical method to account for the effect of ISP on the ground movement. Then, a numerical model to consider ISP and sequential jacking process was established and a series of simulations were carried out for a large pipe-roof tunnelling project. By comparing with the analytical results, the deviation coefficients were determined for the proposed model and the effect of ISP on the surface settlement was further revealed. Finally, the rationality and effectiveness of the proposed method were confirmed by contrasts with traditional methods and numerical calculations. The results show that an approximately 37% error rate could be reduced by the new method. This research is helpful for a better understanding of the effect of ISP, and therefore benefits the effective prediction and control of the surface settlement induced by pipe-roof tunnelling.

Robust Backstepping Control for a Class of Nonlinear Systems using Generalized Disturbance Observer

Jiang Wang,Shaoming He,Defu Lin 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.6

This paper presents a new composite robust controller for a class of uncertain nonlinear systems throughbackstepping method and disturbance observer (DOB) technique. By designing a generalized disturbance observer(GDOB), the mismatched/matched uncertainty is estimated and compensated at each backstepping step. By virtueof the proposed GDOB, the proposed controller only requires the lumped uncertainties are differentiable and thehigher-order derivatives are bounded. With the help of GDOB, the high-gain backstepping controller is also avoidedcompletely. Asymptotical stability of the closed-loop system is established using direct Lyapunov method. Anillustrative example of missile autopilot design is given and simulations are carried out to validate the proposedmethod.

Investigation on the Stratigraphic Response and Plugging Effect Induced by Press-In Open Caisson in Mucky Soil

Yongzhi Wang,Mengbo Liu,Shaoming Liao,Qiong Yi,Junzuo He,Linqi Liu,Zhiqun Gong,Kaiying Li 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

Press-in open caisson method, which sinks into soil with the aid of mechanical pressure without excavation, is becoming an important method of construction in extremely soft foundations. However, many engineering problems are prone to occur in the construction of caissons, such as sinking and large deformation. In this study, the stratigraphic response model, such as soil migration during the press-in process of open caisson, is focused on. Through model tests of soil and caissons, the migration patterns of each part of the soil were carried out, and the mechanism underlying the stratigraphic response pattern was investigated. The three primary conclusions are as follows: 1) The bottom edge foot of caisson produces lateral extrusion on surrounding soil in the range of 10 cm (20%H) below, resulting in lateral movement of soil. 2) two kinds of plug, i.e., “wedged” and “unwedged” plugs exist, and the driven forces for the soil migration can be divided into three stages, i.e., caused by soil plug with active arch, by soil plug with passive arch and caused by soil squeezing effect. 3) there is a significant linear correlation between the soil plug changes, the horizontal movement of the deep soil body, and the displacement of the surface uplift. The soil plugging effect and squeezing effect are interacted and enhanced with each other. This study provides a new understanding of the stratigraphic response in the construction of press-in open caissons, andguides safety control of open caissons construction.