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Vibrations in dynamical structures, as those encountered for instance in mechanical, aerospace or civil engineering, are often caused by internal or external excitations. One way to attenuate vibrations that can be undesirable for safety or other reasons is by the use of active control systems. This means to use feedback controllers driving actuators at appropriate locations between the structure...
In many applications of motion control, problems associated with imprecisely measured or changing load (mass or moment of inertia) constitute a serious obstacle in the design of satisfactory controlling systems, more and more often compelling the introduction of various forms of uncertainties to engineering solutions. This paper deals with the time-optimal control for mechanical systems with uncertain...
This paper deals with the controller design for the lateral motion of automatic steering of vehicles. The nonlinear models without and with uncertainties are considered. Sliding mode controllers with first order sliding surfaces are proposed for the control of lateral velocity and yaw rate. These controllers are designed directly based on the second order differential equation model which simplifies...
This paper describes the robust suboptimal algorithm for a time-varying plant with unknown parameters and an uncontrollable disturbance. The algorithm provides minimization of a performance index with a given accuracy and transfers the plant from the known initial point to the known final point. Efficiency of the proposed scheme is illustrated by modeling.
This paper concerns motion control of single-rod hydraulic actuators with nonlinear unknown parameters. Most previous adaptive controls for hydraulic system only handle linear unknown parameters by assuming the original control volume is certain and known. But in some cases, they might be unknown or change, hence some unknown parameters appear nonlinearly. This paper presents a nonlinear adaptive...
Renewable energy sources such as Solar, wind etc. have gained a lot of interest and application in the recent years, as they can provide electric power on a large scale and are environment friendly. The advancement in the technology of these renewable energy systems has been investigated now a days with a lot of interest. An integral component of the power electronics system that interfaces a renewable...
In this paper, a new robust control strategy to accomplish the precise control of robot manipulators under load uncertainty is proposed using a nonlinear optimal control formulation and solution. This approach is based on the underlying relation between the robust stability and performance optimality. A class of robust control problems can be transformed to an equivalent optimal control problem by...
This paper proposes a robust integral sliding mode (RISM) manifold and the corresponding design method of stabilization control law for uncertain systems with control input time delay. Delay-independent sufficient condition for the existence of the RISM surface is given in terms of LMI, and the sliding mode control (SMC) law which can keep system stay on the neighborhood of the RISM surface in finite...
This article presents a new robust control framework for transportation problems in which the state is modeled by a first order scalar conservation law. Using an equivalent formulation based on a Hamilton-Jacobi equation, we pose the problem of controlling the state of the system on a network link, using boundary flow control, as a Linear Program. Unlike many previously investigated transportation...
The use of active magnetic bearings (AMB) is increasing in high-speed applications, because their low friction operation allows higher rotational speeds than the traditional bearings. The inherent instability and complexity of the AMB rotor system with high nonlinearities pose challenges to the controller design. This leads to a problem of robust design. Robustness of LQG and loop-shaping H∞ controllers...
This paper presents a sampled-data approach for the robust decoherence control of a single qubit. The required robustness is defined using a sliding mode domain and the control law is designed offline and then utilized online with a single qubit having bounded uncertainties. Two classes of uncertainties are considered involving the system Hamiltonian and the coupling strength of the system-environment...
High-performance robust synchronization motion control for quad-cylinder electro-hydraulic lift systems with parametric uncertainties and uncertain nonlinearities is considered. Adaptive Fuzzy logic systems are introduced as an approximator to counteract the effects of coupling among acceleration terms. Robust adaptive control by backstepping is used to handle parametric uncertainties and uncertain...
A new non-smooth robust nonlinear control approach is proposed for robotic manipulators. Compared with the existing robust nonlinear control for robots, the new developed can achieve higher control precision and faster convergence speed. The stability property is analyzed in terms of Lyapunov redesign method. An illustrative example is presented to validate the effectiveness of the proposed approach.
The Disturbance Observer (DOB) is widely used in many robust control applications such as robotics and industrial automation due to its simplicity and efficiency. The DOB estimates and compensates the system disturbances by using an inner-feedback loop in the range of its bandwidth. It includes the inverse of the nominal system model and a low pass filter (LPF) which determines the bandwidth of the...
In this paper we propose a new robust depth control scheme for autonomous underwater vehicles (AUV) in the presence of hydrodynamic parameter uncertainties and disturbances. The controller is designed via an indirect robust control method that handles the uncertainties by formulating the uncertainty bounds into the cost function and then transforming the robust control problem into an equivalent optimal...
This paper presents a sampled-data control approach based on sliding mode design for the robust control of a two-level quantum system, where the control law can be designed offline and then be used online for a quantum system with bounded uncertainties in the system Hamiltonian. Such a control law consists of a periodic sampling process and a Lyapunov control design. A sufficient condition on the...
A modeling and Robust Control Strategy is presented for the pointing mechanism of a typical Altitude-Azimuth telescope. The nonlinear control problem is solved in two stages. In the first, feedback linearization is used to obtain a linear system, with possible uncertainty present owing to lack of exact cancelation in the feedback linearization stage. With these uncertainties, a Robust Control law...
Traditional adaptive control algorithms are not robust to dynamic uncertainties. A new self-tuning regulator is designed based on optimal robust control such that all signals in the closed-loop remain bounded for any bounded inputs regardless of the uncertainty in the parameters of the nominal plant and the presence of the non-parametric uncertainty. The graphs of both the plant and the controller...
For the severe nonlinearity and time-varied problems of controlled object existed in mine sweeping plough electro-hydraulic servo system of a weapon, this paper presents a discrete-time sliding mode control technique using fast output sampling. Fast output sampling enables arbitrary sliding mode design and an equivalent fast output feedback control. In practice the system states needed in the sliding...
The paper considers the problem of automatic path tracking by autonomous farming vehicles subject to wheel slips, which are characteristic for agricultural applications. Two guidance laws are proposed to solve this problem, and both explicitly take into account the constraints on the steering angle and ensure tracking an arbitrarily curved path. The first law is implemented by the pure sliding-mode...
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