In this paper a nonlinear attitude tracking control scheme is developed for a small-scaled unmanned helicopter under input constraints. Via the analysis of the properties associated with the helicopter's rotor dyn...
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ISBN:
(纸本)9781479932757
In this paper a nonlinear attitude tracking control scheme is developed for a small-scaled unmanned helicopter under input constraints. Via the analysis of the properties associated with the helicopter's rotor dynamics, the elevator servo input, the aileron servo input, and the rudder servo input are chosen to be the control inputs to be designed. Their constraints in amplitude under hovering flight is taken into account by using the robust bounded terms in the controller design. The asymptotic convergence of the tracking error is guaranteed with the Lyapunov-based stability analysis.
In this paper, the problem for the control of a class of single-input-single-output (SISO) non-affine nonlinear system with non-varnishing disturbance is investigated. A continuous nonlinear feedback structure is util...
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ISBN:
(纸本)9781479932757
In this paper, the problem for the control of a class of single-input-single-output (SISO) non-affine nonlinear system with non-varnishing disturbance is investigated. A continuous nonlinear feedback structure is utilized to tackle with the uncertain dynamics in the system. By taking the time derivative of the origin system, a transformed affine-like form is derived. The first order derivative of control input appears linearly in the augmented dynamics with unknown control direction. Nussbaum-type function is incorporated to estimate the unknown control direction. A revised Lyapunov based analysis is carried out to prove that under some moderate assumptions, the Semi-global Uniformly Ultimately Bounded (SGUUB) tracking result is achieved and all the closed loop signals are bounded. Numerical simulation results are presented to illustrate the performance of the proposed control law.
Solar tower power plant is the widest market prospect type in large-scale solar power plants during the next decades. Heliostats are the most important components in this system. To solve the problems in the sun-track...
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Solar tower power plant is the widest market prospect type in large-scale solar power plants during the next decades. Heliostats are the most important components in this system. To solve the problems in the sun-tracking, concentrating control and low dynamic precision of the heliostat clusters system, the nonlinear kinematical model of a heliostat is developed based on analysis of the two-axis rotation sun-tracking mechanism and property. The motion trajectory information of a single heliostat is sampled by using a sun's image reference system combined with machine vision-based method. Nonlinear optimization is proposed to get the best sun's image fitting to achieve the heliostat model parameters automatic intelligent calibration, which overcome the sun-tracking and concentrating precision drift caused by mechanical wears of the heliostat, the environmental and seasonal variations and achieve the high focusing rate and high efficiency of the energy collecting of the large-scale heliostat clusters. The effectiveness of proposed modeling, calibration, and control theory of heliostats are verified through theoretical simulation and experimental researches.
As one of key technologies in photovoltaic converter control, Maximum Power Point Tracking (MPPT) methods can keep the power conversion efficiency as high as nearly 99% under the uniform solar irradiance condition. Ho...
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As one of key technologies in photovoltaic converter control, Maximum Power Point Tracking (MPPT) methods can keep the power conversion efficiency as high as nearly 99% under the uniform solar irradiance condition. However, these methods may fail when shading conditions occur and the power loss can over as much as 70% due to the multiple maxima in I – P curve in shading conditions v.s. single maximum point in uniformly solar irradiance. In this paper, a Real Maximum Power Point Tracking (RMPPT) strategy under Partially Shaded Conditions (PSCs) is introduced to deal with this kind of problems. An optimization problem, based on a predictive model which will change adaptively with environment, is developed to tracking the global maxima and corresponding adaptive control strategy is presented. No additional circuits are required to obtain the environment uncertainties. Finally, simulations show the effectiveness of proposed method.
In this paper, new Lyapunov-based reset rules are constructed to improve ℒ 2 gain performance of linear-time-invariant (LTI) systems. By using the hybrid system framework, sufficient conditions for exponential and fin...
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In this paper, new Lyapunov-based reset rules are constructed to improve ℒ 2 gain performance of linear-time-invariant (LTI) systems. By using the hybrid system framework, sufficient conditions for exponential and finite gain ℒ 2 stability are presented. It is shown that the ℒ 2 gain of the closed loop system with resets can be improved compared with the base system. Numerical example supports our results.
This paper studies the semi-global leader-following consensus problem for a group of linear systems in the presence of both actuator position and rate saturation. Each follower agent in the group is described by a gen...
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This paper studies the semi-global leader-following consensus problem for a group of linear systems in the presence of both actuator position and rate saturation. Each follower agent in the group is described by a general linear system subject to simultaneous actuator position and rate saturation. We construct a low gain based linear state feedback control law for each follower agent and show that semi-global leader-following consensus can be achieved by using these control laws when the communication topology among follower agents is a connected undirected graph and the leader is a neighbor of at least one follower. Simulation results illustrate the theoretical results.
This paper revisits the problem of estimating the domain of attraction for systems with saturation *** divide the input space into several regions. In one of these regions, none of the inputs saturate. In each of the ...
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ISBN:
(纸本)9781479947249
This paper revisits the problem of estimating the domain of attraction for systems with saturation *** divide the input space into several regions. In one of these regions, none of the inputs saturate. In each of the remaining regions, there is a unique input that saturates everywhere with the time-derivative of its saturated signal being zero. These special properties of the inputs in different regions of the input space are combined with an existing piecewise quadratic Lyapunov functions that contains the information of input saturation to arrive at a set of less conservative stability conditions, from which a larger level set of the piecewise quadratic Lyapunov function can be obtained as an estimate of the domain of *** results indicate that the proposed approach has the ability to obtain a significantly larger estimate of the domain of attraction than the existing methods.
This paper considers reset controlsystems with output *** present sufficient conditions for the quadratic stability and finite L2 gain ***,the results are extended to piecewise quadratic stability which is much less ...
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ISBN:
(纸本)9781479947249
This paper considers reset controlsystems with output *** present sufficient conditions for the quadratic stability and finite L2 gain ***,the results are extended to piecewise quadratic stability which is much less ***,an iterative algorithm is proposed to design the reset *** the obtained results are given as linear matrix inequalities(LMIs) that can be solved *** examples are given to illustrate the results.
In this paper, we consider the control of large-scale processes with both input and state couplings. A distributed model predictive control(MPC) strategy for tracking based on the reference trajectories is presented. ...
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ISBN:
(纸本)9781479947249
In this paper, we consider the control of large-scale processes with both input and state couplings. A distributed model predictive control(MPC) strategy for tracking based on the reference trajectories is presented. The proposed distributed MPC strategy requires decomposing a large-scale system into several smaller ones and solving convex optimization problems independently. Distributed MPC tracking strategies for unconstrained and constrained processes are presented, respectively. An iterative algorithm is presented to coordinate the distributed MPC controllers. The proposed algorithm is applied to a four-tank process to demonstrate the effectiveness.
A nonlinear self-excited vibration model of main drive system in cold rolling is established. The mechanism of torsional vibration in main drive system stability is discussed within multiple scale method as well as Ho...
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A nonlinear self-excited vibration model of main drive system in cold rolling is established. The mechanism of torsional vibration in main drive system stability is discussed within multiple scale method as well as Hopf bifurcation theorem. Then, the periodic solutions and condition of Hopf bifurcation are derived and the influence by subcritical/supercritical bifurcation is analyzed. Based on the simulation experiments with actual industrial data, the previous theoretical analysis and nonlinear model have been testified.
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