Active Control of Longitudinal Vibration of a Time-Varying Shafting System With a Dynamic Interpolating Adaptive Method

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Hongbo Zheng ◽  
Fang Hu ◽  
Hui Qin ◽  
Zhiyi Zhang
Keyword(s):  
Thrust Bearing ◽  
Control Method ◽  
Longitudinal Vibration ◽  
Adaptive Methods ◽  
Adaptive Method ◽  
Control Force ◽  
Time Varying ◽  
The Stability ◽  
The Right ◽  
Parameter Dependent

An adaptive control method with dynamic interpolation is proposed for the active longitudinal vibration control of propulsion shafting systems. In such systems, the dynamics of longitudinal vibration change with the speed-dependent stiffness, which can result in a time-varying system as the shaft speed changes with time. A longitudinal vibration model is established for the investigation of the dynamic interpolating adaptive method (DIAM). In this model, the longitudinal vibration is induced by the disturbance exerted on the propeller (the left mass) and the control force is exerted on the thrust bearing (the right mass), which defines the disturbance channel and the control channel. The proposed DIAM is used to suppress longitudinal vibration transmission from the propeller to the thrust bearing by applying an active force on the right mass. The interpolation technique in DIAM updates the parameter-dependent compensator dynamically and eliminates the influence of parameter-dependent dynamics on the stability of control. Simulation results have demonstrated that the proposed DIAM is effective in suppressing longitudinal vibration of the thrust bearing in comparison to conventional adaptive methods.

scholarly journals Formation Control of Unmanned Vessels with Saturation Constraint and Extended State Observation

2021 ◽  
Vol 9 (7) ◽  
pp. 772
Author(s):  
Huixuan Fu ◽  
Shichuan Wang ◽  
Yan Ji ◽  
Yuchao Wang
Keyword(s):  
Formation Control ◽  
Control Method ◽  
Tracking Error ◽  
External Environment ◽  
Control Force ◽  
Extended State ◽  
Parameter Perturbation ◽  
State Observation ◽  
Saturation Constraint ◽  
The Stability

This paper addressed the formation control problem of surface unmanned vessels with model uncertainty, parameter perturbation, and unknown environmental disturbances. A formation control method based on the control force saturation constraint and the extended state observer (ESO) was proposed. Compared with the control methods which only consider the disturbances from external environment, the method proposed in this paper took model uncertainties, parameter perturbation, and external environment disturbances as the compound disturbances, and the ESO was used to estimate and compensate for the disturbances, which improved the anti-disturbance performance of the controller. The formation controller was designed with the virtual leader strategy, and backstepping technique was designed with saturation constraint (SC) function to avoid the lack of force of the actuator. The stability of the closed-loop system was analyzed with the Lyapunov method, and it was proved that the whole system is uniformly and ultimately bounded. The tracking error can converge to arbitrarily small by choosing reasonable controller parameters. The comparison and analysis of simulation experiments showed that the controller designed in this paper had strong anti-disturbance and anti-saturation performance to the compound disturbances of vessels and can effectively complete the formation control.

Moving sliding mode controller for overhead cranes suffering from matched and unmatched disturbances

2020 ◽  
pp. 014233122092210
Author(s):  
Xiutao Gu ◽  
Weimin Xu
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Input Saturation ◽  
Time Varying ◽  
Initial State ◽  
Overhead Cranes ◽  
State Variable ◽  
Chattering Free ◽  
The Stability ◽  
Variable Errors

In this paper, a novel time-varying gain extended state observer (ESO)-based moving sliding mode control method is proposed for anti-sway and positioning control of two-dimensional underactuated overhead cranes. The designed moving sliding mode surface can adjust its slope in real time according to the state variable errors; in addition, a dynamic exponential term is added into the moving sliding mode surface so as to drive any initial state variable errors into the sliding surface rapidly, and thereby the robustness of crane systems is improved. Then, a chattering-free reaching law is designed to realize fast convergence of the system state errors, and the input is modelled as a saturated one due to the fact the motor torque is bounded and the control law and adaptive updating law of switching gain are derived in the sense of Lyapunov function, so the stability can be guaranteed even under the input saturation. Moreover, to suppress the matched and unmatched disturbance occurring in crane dynamic systems, a time-varying gain ESO is constructed to estimate the lumped disturbance, then the estimated value is used for feedforward compensation to establish the controller. Finally, the simulation results confirm the effectiveness of the proposed controller.

scholarly journals Robust Gain-Scheduled PID Control: A Parameter Dependent BMI Solution

2020 ◽  
Vol 20 (1) ◽  
pp. 156-167
Author(s):  
Pengyuan Shao ◽  
Jin Wu ◽  
Songhui Ma
Keyword(s):  
Robust Control ◽  
Pid Control ◽  
Optimization Problem ◽  
Simple Structure ◽  
Control Method ◽  
Time Varying ◽  
Linear Parameter Varying ◽  
Parameter Dependent ◽  
Gain Scheduled ◽  
Static Output

AbstractIn control practices, problems of parametric or time-varying uncertainties must be dealt with. Robust control based on norm theory and convex and non-convex optimization algorithms is a powerful tool to solve these problems in theory, but it is employed rarely in applications. In most engineering cases, Proportional-Integration-Derivative (PID) control is still the most popular method for its easy-to-tune and controllable properties. The control method proposed in this paper integrates the PID control into robust control formulation as a robust Structured Static Output Feedback (SSOF) problem of Linear-Parameter-Varying (LPV) systems, which can be converted into a Parameter Dependent Bilinear-Matrix-Inequality (PDBMI) optimization problem. A convex-concave decomposition based method is given to solve the proposed PDBMI problem. The proposed solution has a simple structure in PID form and can guarantee stability and robustness of the system being controlled in the whole operation range with less conservativeness than existing solution.

scholarly journals H∞Control for a Networked Control Model of Systems with Two Additive Time-Varying Delays

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hanyong Shao ◽  
Zhengqiang Zhang ◽  
Xunlin Zhu ◽  
Guoying Miao
Keyword(s):  
Upper Bound ◽  
Lyapunov Functional ◽  
Control Method ◽  
Control Model ◽  
Networked Control ◽  
Disturbance Attenuation ◽  
Time Varying ◽  
Stability Criteria ◽  
The Stability ◽  
Polyhedron Method

This paper is concerned withH∞control for a networked control model of systems with two additive time-varying delays. A new Lyapunov functional is constructed to make full use of the information of the delays, and for the derivative of the Lyapunov functional a novel technique is employed to compute a tighter upper bound, which is dependent on the two time-varying delays instead of the upper bounds of them. Then the convex polyhedron method is proposed to check the upper bound of the derivative of the Lyapunov functional. The resulting stability criteria have fewer matrix variables but less conservatism than some existing ones. The stability criteria are applied to designing a state feedback controller, which guarantees that the closed-loop system is asymptotically stable with a prescribedH∞disturbance attenuation level. Finally examples are given to show the advantages of the stability criteria and the effectiveness of the proposed control method.

scholarly journals Fault Diagnosis and Reconfigurable Control for Commercial Aircraft with Multiple Faults and Actuator Saturation

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 108
Author(s):  
Yishi Liu ◽  
Sheng Hong ◽  
Enrico Zio ◽  
Jianwei Liu
Keyword(s):  
Fault Diagnosis ◽  
Control Method ◽  
Actuator Saturation ◽  
Fault Tolerant ◽  
External Disturbance ◽  
Fault Tolerant Control ◽  
Adaptive Method ◽  
Reconfigurable Control ◽  
Multiple Faults ◽  
The Stability

Active fault-tolerant control systems perform fault diagnosis and reconfigurable control. There is a bidirectional uncertainty between them, and an integrated scheme is proposed here to account for that. The system considers both actuator and sensor faults, as well as the external disturbance. The diagnostic module is designed using an unknown input observer, and the controller is constructed on the basis of an adaptive method. The integrated strategy is presented, and the stability of the overall system is analyzed. Moreover, different kinds of anti-windup techniques are utilized to modify the original controllers, because of the different controller structures. A simulation of the integrated anti-windup fault-tolerant control method is demonstrated using a numerical model of Boeing 747. The results show that it can guarantee the stability of the post-fault aircraft and increase the control performance for the overall faulty system.

Boundary Stabilization of Parachute Dams in Contact With Fluid

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Ali Najafi ◽  
Mohammad Eghtesad ◽  
Farhang Daneshmand ◽  
Amir Lotfazar
Keyword(s):  
Stability Analysis ◽  
Lyapunov Functional ◽  
Control Method ◽  
Nonlinear Partial Differential Equations ◽  
Coupled System ◽  
Control Force ◽  
Boundary Stabilization ◽  
Boundary Feedback ◽  
Boundary Control Method ◽  
The Stability

The boundary stabilization of a coupled fluid-structure system consisting of a vibrating parachute dam in contact with a fluid is studied in this paper. The parachute dam dynamics is presented by nonlinear partial differential equations. The fluid is assumed to be Newtonian, barotropic, and compressible. For the stability analysis of the coupled system, the boundary control method is used; a boundary feedback is constructed to stabilize the vibrations of the dam and the fluid simultaneously. The control force consists of the feedback from dam tension at its end. Moreover, the exponential stabilization of the parachute dam is achieved using a Lyapunov functional and boundary feedback.

scholarly journals The Theory of Pulsating Flow in Conical Nozzles

1963 ◽  
Vol 30 (1) ◽  
pp. 1-6 ◽  
Author(s):  
H. G. Elrod
Keyword(s):  
Pressure Fluctuation ◽  
Thrust Bearing ◽  
Solid Angle ◽  
Operating Conditions ◽  
Time Varying ◽  
Nozzle Throat ◽  
Outlet Pressure ◽  
Inlet Conditions ◽  
The Stability ◽  
Flux Response

A knowledge of the dynamic characteristics of nozzles and orifices is important in many control and stability analyses of engineering devices. It is usual to assume that the instantaneous flowrate, for a given set of inlet conditions and outlet pressure, is the same as the nontransient value for the same operating conditions. Recently, in connection with the stability analysis of an externally pressurized thrust bearing, the validity of this assumption was questioned. The analysis presented in this paper was undertaken to provide an answer. The present analysis applies to any fluid, liquid, or gas flowing into a simple conical nozzle. The amplitude and phase of the mass-flux response to a sinusoidally time-varying pressure fluctuation at the nozzle exit are determined. An approximate formula is given for these quantities in terms of the nozzle throat area, the solid angle subtended by the cone, the velocity of the fluid at the nozzle throat, the acoustic velocity at the throat, and the frequency of the pressure fluctuation.

Intelligent Control Method for Aircraft Deicing Fluidtemperature Based on a New Adaptive Smith Predictor

2012 ◽  
Vol 424-425 ◽  
pp. 936-940 ◽  
Author(s):  
Zhi Wei Xing ◽  
Bing Jun Ding
Keyword(s):  
Pid Control ◽  
Control Method ◽  
Rapid Heating ◽  
Heating System ◽  
Smith Predictor ◽  
Time Varying ◽  
Fuzzy Pid Control ◽  
Non Linear ◽  
Deicing Fluid ◽  
The Stability

During the course of industry control, pure hysteresis, time-varying，non- linear complex systems often occur. It is ineffective to solve the issues above with the traditional fuzzy control and PID control methods. Against the pure hysteresis, time-varying, non- linear characteristics of Aircraft Deicing Fluid rapid heating system, on the basis of Smith Predictor and traditional PID, a Fuzzy-PID control method is proposed based on an adaptive Smith predictor. In this way, pure hysteresis of the system will be compensated, to reduce the overshoot and enhance the stability of the system. By establishing the mathematical model of Aircraft Deicing Fluid rapid heating system and simulating for the model obtain the simulation results, which have shown that the method is effective, can improve the qualities of control and enhance the stability of temperature control system significantly

scholarly journals Robust Exponential Stability Criteria of LPD Systems with Mixed Time-Varying Delays and Nonlinear Perturbations

2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Kanit Mukdasai ◽  
Akkharaphong Wongphat ◽  
Piyapong Niamsup
Keyword(s):  
Exponential Stability ◽  
Linear Matrix ◽  
Time Varying ◽  
Nonlinear Perturbations ◽  
Matrix Inequalities ◽  
Stability Criteria ◽  
Robust Exponential Stability ◽  
The Stability ◽  
Delay Dependent ◽  
Parameter Dependent

This paper investigates the problem of robust exponential stability for linear parameter-dependent (LPD) systems with discrete and distributed time-varying delays and nonlinear perturbations. Parameter dependent Lyapunov-Krasovskii functional, Leibniz-Newton formula, and linear matrix inequality are proposed to analyze the stability. On the basis of the estimation and by utilizing free-weighting matrices, new delay-dependent exponential stability criteria are established in terms of linear matrix inequalities (LMIs). Numerical examples are given to demonstrate the effectiveness and less conservativeness of the proposed methods.

Symmetrizable Difference Dchemes

2005 ◽  
Vol 5 (1) ◽  
pp. 3-50 ◽  
Author(s):  
Alexei A. Gulin
Keyword(s):  
Initial Data ◽  
Difference Scheme ◽  
Difference Schemes ◽  
Time Dependent ◽  
Stability Boundaries ◽  
Typical Representative ◽  
Variable Weight ◽  
The Stability ◽  
Conditions Of Stability ◽  
The Right

AbstractA review of the stability theory of symmetrizable time-dependent difference schemes is represented. The notion of the operator-difference scheme is introduced and general ideas about stability in the sense of the initial data and in the sense of the right hand side are formulated. Further, the so-called symmetrizable difference schemes are considered in detail for which we manage to formulate the unimprovable necessary and su±cient conditions of stability in the sense of the initial data. The schemes with variable weight multipliers are a typical representative of symmetrizable difference schemes. For such schemes a numerical algorithm is proposed and realized for constructing stability boundaries.

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