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Enhanced anti-windup (AW) schemes are designed for the dual stage hard disk drive (HDD) system to solve the amplitude saturation problem of the secondary actuator. The sensitivity decoupling approach is used for designing the nominal linear controllers for the dual stage HDD systems. The AW compensators for the system are synthesized by solving a linear matrix inequality optimization. The AW scheme...
This paper presents a novel Lyapunov-type functional to develop a new robust control method for general time-varying delay stochastic uncertain systems with Brownian motion (Wiener process) and structural uncertainties. The proposed novel Lyapunov-type functional can effectively treat the general cases where the state derivative does not exist due to Brownian motion and the derivative of time-varying...
A global task coordinate frame (GTCF) based learning adaptive robust controller (LARC) is practically synthesized for an industrial X-Y linear-motor-driven stage to achieve not only good parametric adaptation ability and uncertain disturbance robustness, but also excellent transient/steady-state contouring performance. With the employment of GTCF which is globally based on the shape of the desired...
Recent work on control Lyapunov functions and control Barrier functions has enabled addressing stability of nonlinear and underactuated hybrid systems while simultaneously enforcing input / state constraints and safety-critical constraints. However, under model uncertainty, these controllers break down and violate constraints. This paper presents a novel method of optimal robust control through quadratic...
Robust stability synthesis of a class of uncertain parameter-varying first-order time-delay systems is presented in this paper. Internal model principle is used to design a robust control using ℋ∞ small-gain theorem. The closed-loop system robustness is investigated against bounded variation of the parameters and sensitivity analysis is performed to determine the stability conditions and provide a...
We propose a new method for controlling rigid robot manipulators guaranteeing that a user-defined tracking performance is ultimately met while facing uncertain system dynamics and input disturbance. Our control approach is based on the passivity-based control technique and eliminates the limitations of existing methods (e.g. impractical tuning to avoid chattering and difficult estimation of uncertainty...
In this paper, a strategy is established to design the robust controller for a class of continuous-time nonlinear systems with Lurie uncertainties.The uncertainty is decomposed into matched and unmatched components, and an augmented control is introduced for the unmatched uncertainty. An optimal control algorithm based on Hamilton-Jacobi-Bellman(HJB) equation is proposed for the design of a bounded...
In this paper, we propose an approach for designing a discrete-time model matching active disturbance rejection control (ADRC). The ADRC is a design method that achieves a high performance for disturbance estimation and compensation using an extended state observer (ESO), which estimates the plant state variables and generalized perturbation and then offsets it. However, when the input-side disturbance...
We revisit the issue of gain-scheduled versus robust control with a focus on matrix inequalities. It has been established that for uncertain continuous-time linear systems that depend affinely on the uncertainty, gain-scheduled stabilizability implies robust stabilizability. That is, as far as stabilizability is concerned, using a more complex gain-scheduled controller brings no advantage. In the...
A robust adaptive terminal controller is proposed for attitude system of near space vehicle. Firstly, NSV dynamic model is presented, which includes nonlinear, uncertainty and disturbance. Secondly, an second order sliding mode disturbance observer is used to estimate the unknown disturbance. Then, in order to overcome the chattering problem in traditional sliding mode, the design process of second-order...
Stabilization of gimbal platform housing the payload in Micro Air Vehicle (MAV) applications is crucial in operational situations. The gimbal positioning is achieved through a DC servo motor, which needs to be controlled for the desired performance under uncertainty and disturbance. In this work a novel robust control strategy employing the technique of Uncertainty and Disturbance Estimator (UDE)...
A method is presented for synthesizing output estimators for a class of continuous time, uncertain, linear parameter-varying (LPV) systems. The uncertain system is described as an interconnection of a nominal LPV system and a block structured perturbation. The nominal LPV system is “gridded” over the space of parameters, with the state matrices being arbitrary functions of the parameters. The input/output...
In this article, we propose sufficient conditions for robust observer-based control of uncertain linear systems with polytopic uncertainties and unknown disturbances. The observer and the controller gains are obtained from the solution of a convex-optimization problem. Mixed performance constraints are imposed on the design in order to minimize the effects of the unknown disturbances on the overall...
This paper presents a novel tracking controller for a three degrees-of-freedom permanent magnet spherical actuator (PMSA). The controller is designed on the basis of the establishment of dynamics model under uncertainties. The major construction of the controller lies in the use of the matrix regressor to isolate unknown parameters from the PMSA. Moreover, sliding-mode control and robust control are...
We employ a numerical optimal control algorithm to learn optimal control fields for achieving a special simultaneous state transformation in CO molecules. The simultaneous state transformation means that for different initial states, the same control fields can accomplish the control task of driving them into relevant desired target states. The sampling-based learning control method is applied to...
The sampling points in one cycle of 400 Hz inverter is 8 times less than that of 50 Hz inverter, resulting in lower control accuracy and larger static error in 400 Hz power supply system. According to the characteristics of the 400 Hz inverter, this paper establishes a mathematical model for single-phase solid-static power supply system. The changes in line impedance and load can be considered as...
Voltage converter circuits are fundamental components in power electronics applications. However, their paramount role on various appliances due to their well-known benefits comes together with difficulties and restrictions for their modeling and control. A buck converter is naturally subjected to non-linearities, time-dependency, noise, and parameter variations. Altogether, it is difficult to provide...
This paper focuses on a robust cooperative output tracking problem of networked power integrator systems. The dynamics of each system is considered as a nonlinear high-order power integrator whose linearized model is uncontrollable around its origin. It is proven via Lyapunov Theory that under some mild assumptions and graph structural properties, all agents' outputs in the network can be synchronized...
This paper addresses tube-based robust model predictive control (RMPC) for constrained continuous-time nonlinear systems with additive uncertainties. The RMPC is designed based on a linear feedback term and a model predictive control (MPC) for a continuous-time nonlinear system. Firstly, a robust control invariant set is explicitly given for the error system between the nonlinear system and its nominal...
For the longitudinal dynamics of hypersonic vehicles with multiple uncertainties and time varying delays, a design method of robust controllers is proposed to control the velocity and height channels of the hypersonic vehicles model. To reduce the effects of the multiple uncertainties, the controller is designed including a full state feedback controller and a robust compensator. The robust stability...
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