Showing papers on "Feedback linearization published in 2009"
TL;DR: In this paper, two types of nonlinear controllers for an autonomous quadrotor helicopter are presented: a feedback linearization controller and an adaptive sliding mode controller using input augmentation in order to account for the underactuated property of the helicopter, sensor noise, and uncertainty.
Abstract: This paper presents two types of nonlinear controllers for an autonomous quadrotor helicopter. One type, a feedback linearization controller involves high-order derivative terms and turns out to be quite sensitive to sensor noise as well as modeling uncertainty. The second type involves a new approach to an adaptive sliding mode controller using input augmentation in order to account for the underactuated property of the helicopter, sensor noise, and uncertainty without using control inputs of large magnitude. The sliding mode controller performs very well under noisy conditions, and adaptation can effectively estimate uncertainty such as ground effects.
637 citations
14 Apr 2009
TL;DR: In this paper, the authors describe the development of a nonlinear vehicle control system based on a decomposition into a nested structure and feedback linearization which can be implemented on an embedded microcontroller.
Abstract: Four-rotor micro aerial robots, so called quadrotor UAVs, are one of the most preferred type of unmanned aerial vehicles for near-area surveillance and exploration both in military and commercial in- and outdoor applications. The reason is the very easy construction and steering principle using four rotors in a cross configuration. However, stabilizing control and guidance of these vehicles is a difficult task because of the nonlinear dynamic behavior. In addition, the small payload and the reduced processing power of the onboard electronics are further limitations for any control system implementation. This paper describes the development of a nonlinear vehicle control system based on a decomposition into a nested structure and feedback linearization which can be implemented on an embedded microcontroller. Some first simulation results underline the performance of this new control approach for the current realization.
322 citations
TL;DR: This paper deals with vision-based localization for leader-follower formation control with a new observability condition valid for general nonlinear systems and based on the extended output Jacobian.
Abstract: This paper deals with vision-based localization for leader-follower formation control. Each unicycle robot is equipped with a panoramic camera that only provides the view angle to the other robots. The localization problem is studied using a new observability condition valid for general nonlinear systems and based on the extended output Jacobian. This allows us to identify those robot motions that preserve the system observability and those that render it nonobservable. The state of the leader-follower system is estimated via the extended Kalman filter, and an input-state feedback control law is designed to stabilize the formation. Simulations and real-data experiments confirm the theoretical results and show the effectiveness of the proposed formation control.
170 citations
TL;DR: The possibility of simplifying the procedure of designing controller for switched nonlinear processes, using the modal state feedback method is illustrated.
163 citations
TL;DR: A four-degree-of-freedom nonlinear surface vessel model, together with the Serret-Frenet equations, is introduced to describe the ship dynamics and path following error dynamics and the performance of the nonlinear controller is analyzed for robustness in the presence of model uncertainties.
136 citations
TL;DR: Several flatness-based current controllers for three-phase three-wire boost rectifiers are compared, and the flatness of a rectifier model is shown, and a trajectory planning algorithm that nominally achieves voltage regulation in finite time is given.
Abstract: Several flatness-based current controllers for three-phase three-wire boost rectifiers are compared. For this purpose, the flatness of a rectifier model is shown, and a trajectory planning algorithm that nominally achieves voltage regulation in finite time is given. The main focus lies on the inner loop current controllers. On one hand, linearization-based controllers using exact feedback linearization, exact feedforward linearization, and input-output linearization are discussed. On the other hand, two passivity-based approaches are compared. The first one is the energy shaping and damping injection method, and the other one uses exact tracking error dynamics passive output feedback. Furthermore, a reduced-order load observer is given, and a method that allows the prevention of invalid switching patterns is presented. The presented control algorithms are tested by simulations on a switched model.
108 citations
11 Jun 2009
TL;DR: In this paper, an altitude stabilization, hovering control and attitude control of a quadrotor was performed using computer simulations and compared the results according to this study objective, using computer simulation.
Abstract: This study includes altitude stabilization, hovering control any desired position and attitude control of quadrotor. Classically PD controller derived and applied to this system. Inverse dynamic control, feedback linearization control and sliding mode control methods have used to derive as nonlinear controllers. Linear and nonlinear control techniques applied to attitude control of this vehicle. Derived control methods have been performed using computer simulations and compared the results according to this study objective.
94 citations
TL;DR: In this article, a sliding-mode feedback linearisation control system is designed for a multi-motor web-winding system, which consists of an SM velocity controller and two SM tension controllers; a decentralised version of the proposed controller is developed.
Abstract: A sliding-mode (SM) feedback linearisation control system is designed for a multi-motor web-winding system. First, an ideal feedback linearisation control system is adopted in order to decouple the tensions and velocity of the web-winding system; then to enhance the performance of the control system in the presence of uncertainties, an SM feedback linearisation control system is applied, which consists of an SM velocity controller and two SM tension controllers; a decentralised version of the proposed controller is developed. Two tension observers are suggested to eliminate the need of load cells in a web-winding system. Finally, the effectiveness and capability of the proposed control strategy is verified by computer simulation.
85 citations
TL;DR: In this article, the authors apply the impedance control on an active vehicle suspension system operated by a hydraulic actuator and derive a relation between the passenger comfort and vehicle handling using the impedance parameters.
84 citations
TL;DR: In this article, an adaptive neural network-based hybrid controller for antilock braking systems is presented, which is based on the well-known feedback linearization, combined with two feedforward neural networks that are proposed so as to learn the nonlinearities of the antilocked braking system associated with feedback linearisation controller.
83 citations
10 Oct 2009
TL;DR: A collision reaction strategy is presented that takes advantage of the proposed nonlinear control to rapidly let the arm bounce away after detecting the impact, while limiting contact forces through a sudden reduction of the stiffness.
Abstract: Variable Stiffness Actuation (VSA) devices are being used to jointly address the issues of safety and performance in physical human-robot interaction. With reference to the VSA-II prototype, we present a feedback linearization approach that allows the simultaneous decoupling and accurate tracking of motion and stiffness reference profiles. The operative condition that avoids control singularities is characterized. Moreover, a momentum-based collision detection scheme is introduced, which does not require joint torque sensing nor information on the time-varying stiffness of the device. Based on the residual signal, a collision reaction strategy is presented that takes advantage of the proposed nonlinear control to rapidly let the arm bounce away after detecting the impact, while limiting contact forces through a sudden reduction of the stiffness. Simulations results are reported to illustrate the performance and robustness of the overall approach. Extensions to the multidof case of robot manipulators equipped with VSA-II devices are also considered.
TL;DR: In this article, a generalized approach for the systematic generation of robust control rules for the boost power factor correction converter is presented, based on a cascading multiloop control structure, a unified approach for deriving the control functions for the inner current loop and the outer voltage loop is proposed.
Abstract: In this paper, a generalized approach for the systematic generation of robust control rules for the boost power factor correction converter is presented. Based on a cascading multiloop control structure, a unified approach for deriving the control functions for the inner current loop and the outer voltage loop is proposed. The resulting control provides unity power factor and regulated average output voltage with fast transient response. The control performance is robust under all practical conditions as a result of the application of feedback linearization. This method eliminates the nonlinearity and the dependence of the error dynamics on the input disturbance. The control parameters can be designed according to the desired steady-state and transient response performances. The resulting control rules are readily implemented in analog circuitries. Experiments are conducted to evaluate the control performance.
TL;DR: In this article, a PC-based controller interfaced to the experimental quadruple tank experimental set up has been used to implement this algorithm and test its performance, and the implemented controller provides robust control and excellent set point tracking.
TL;DR: By utilizing the state feedback exact linearization approach, a nonlinear robust control strategy is designed based on a multiple-input multiple-output (MIMO) dynamic nonlinear model of PEMFC.
TL;DR: In this article, a velocity estimator is proposed based on measurements of current, and the robustness of the tracking is addressed using a minimum variance control approach, which compensates for the tracking error caused by inexact feedback linearization.
TL;DR: A class of single-input single-output nonlinear systems which are partially linearizable by state feedback is considered: feedback linearizable systems are included in such a class; no parametrization is required for the uncertainties which are required to satisfy the matching condition.
Abstract: A class of single-input single-output nonlinear systems which are partially linearizable by state feedback is considered: feedback linearizable systems are included in such a class; no parametrization is required for the uncertainties which are required to satisfy the matching condition. Periodic reference signals with known period T are to be tracked by the output. Provided that known bounding functions on the uncertainties are available, a state feedback iterative learning control is designed which achieves asymptotic output tracking and guarantees bounded closed loop signals from any intial condition. The novel control tecnhique is illustrated for a single-link robot arm.
10 Jun 2009
TL;DR: This article presents an approach to path following control design based on transverse feedback linearization that is applied to a five degree-of-freedom (5-DOF) magnetically levitated positioning system.
Abstract: This article presents an approach to path following control design based on transverse feedback linearization. A “transversal” controller is designed to drive the output of the plant to the path. A “tangential” controller meets application-specific requirements on the path, such as speed regulation and internal stability. This methodology is applied to a five degree-of-freedom (5-DOF) magnetically levitated positioning system. Experimental results demonstrate the effectiveness of our control design.
TL;DR: The proposed robust global linearization filter is potential for practical state estimation of nonlinear stochastic systems with intrinsic random fluctuation and external disturbance and can efficiently be solved by convex optimization techniques via the LMI toolbox of Matlab.
Abstract: This paper proposes a robust global linearization filter design for a nonlinear stochastic system with exogenous disturbance. The nonlinear dynamic system is modeled by Itocirc-type stochastic differential equations. For a general nonlinear stochastic system with exogenous disturbance, the robust H infin filter can be obtained by solving a second-order nonlinear Hamilton-Jacobi inequality (HJI). In general, it is difficult to solve the second-order nonlinear HJI. In this paper, based on the global linearization scheme, the robust H infin global linearization filter design for nonlinear stochastic systems is proposed via solving linear matrix inequalities (LMIs) instead of a second-order HJI. When the worst case disturbance attenuation of H infin filtering is considered, a suboptimal H 2 global linearization filtering problem is also solved by minimizing the upper bound on the H 2 norm of the estimation error variance. The suboptimal global linearization filtering design problem under a desired worst case disturbance attenuation (i.e., the mixed H 2/H infin filtering design problem) is also transformed into a constrained optimization problem characterized in terms of LMI constraints, which can efficiently be solved by convex optimization techniques via the LMI toolbox of Matlab. Therefore, the proposed robust global linearization filter is potential for practical state estimation of nonlinear stochastic systems with intrinsic random fluctuation and external disturbance. A simulation example is provided to illustrate the design procedure and to confirm the expected robust filtering performance.
TL;DR: The necessary and sufficient conditions that guarantee the existence of a diffeomorphism which allows one to transform a multi-output nonlinear dynamical system into a normal observable canonical form are given and an algorithm is proposed that permits one to derive such diffEomorphism.
TL;DR: In this article, a feedback linearization strategy for a solar collector field, which is a constrained nonlinear processes, is proposed to take advantage of linear control without losing the intrinsic nonlinearities typical of thermal power plants.
23 Mar 2009
TL;DR: In this article, the authors developed a nonlinear position controller for a quadrotor VTOL aircraft using feedback linearization with dynamic extension, which completely decouples and linearizes the nonlinear dynamical model of the aircraft.
Abstract: The contribution of this paper is the development of a nonlinear position controller for a quadrotor VTOL aircraft using feedback linearization with dynamic extension. The developed controller completely decouples and linearizes the nonlinear dynamical model of the aircraft. The use of dynamic extension has resulted into a fourteenth dimensional controller for the the twelve dimensional state system. Simulation results are provided to demonstrate the effectiveness of the nonlinear controller in tracking time-parameterized trajectories in inertial frame with internal stability.
TL;DR: The proposed controller ensures that the link position globally tracks the desired trajectory while keeping all the remaining signals bounded, and uses a partial state-feedback linearization technique combined with the integrator backstepping control design method to remove the requirement of link and actuator velocity measurements.
Abstract: This paper investigates the problem of global output feedback tracking control of flexible joint robots. Despite the fact that only link position and actuator position are available from measurements, the proposed controller ensures that the link position globally tracks the desired trajectory while keeping all the remaining signals bounded. The controller development uses a partial state-feedback linearization technique combined with the integrator backstepping control design method whereas a filter and an observer are utilized to remove the requirement of link and actuator velocity measurements. Partial state-feedback linearization of robot dynamics is performed by factoring the manipulator mass matrix into a quadratic form involving an integrable root matrix. The applicability of the proposed general design methodology is illustrated by an example of flexible joint planar robots. Numerical results for a two-link flexible joint planar robot are also provided.
TL;DR: In this article, it is shown that there are two branches for the linearization problem via point transformations for an arbitrary system of second-order ODEs and its reduction to the simplest system.
Abstract: Invariant linearization criteria for square systems of second-order quadratically nonlinear ordinary differential equations (ODEs) that can be represented as geodesic equations are extended to square systems of ODEs cubically nonlinear in the first derivatives. It is shown that there are two branches for the linearization problem via point transformations for an arbitrary system of second-order ODEs and its reduction to the simplest system. One is when the system is at most cubic in the first derivatives. One obtains the equivalent of the Lie conditions for such systems. We explicitly solve this branch of the linearization problem by point transformations in the case of a square system of two second-order ODEs. Necessary and sufficient conditions for linearization to the simplest system by means of point transformations are given in terms of coefficient functions of the system of two second-order ODEs cubically nonlinear in the first derivatives. A consequence of our geometric approach of projection is a ...
TL;DR: The classical epidemic model is adapted to model malware propagation in this multi-network framework and the trade-off between the infection spread and the patching costs is captured in a cost function, leading to an optimal control problem.
01 Mar 2009
TL;DR: A direct adaptive neural control scheme for a class of affine nonlinear systems which are exactly input-output linearizable by nonlinear state feedback and which can be applied for multi-input-multi-output (MIMO) systems whose structure is formulated.
Abstract: This paper presents a direct adaptive neural control scheme for a class of affine nonlinear systems which are exactly input-output linearizable by nonlinear state feedback. For single-input-single-output (SISO) systems of the form [email protected]?=f(x)+g(x)u, the control problem is comprehensively solved when both f(x) and g(x) are unknown. In this case, the control input comprises two terms. One is an adaptive feedback linearization term and the other one is a sliding mode term. The weight update laws for two neural networks, which approximate f(x) and g(x), have been derived to make the closed loop system Lyapunov stable. It is also shown that a similar control approach can be applied for a class of multi-input-multi-output (MIMO) systems whose structure is formulated in this paper. Simulation results for both SISO- and MIMO-type nonlinear systems have been presented to validate the theoretical formulations.
TL;DR: This paper introduces a technique for handling input constraints within a real time MPC/FL scheme, where the plant model employed is a class of dynamic neural networks, based on a simple affine transformation of the feasible area.
Abstract: The combination of model predictive control based on linear models (MPC) with feedback linearization (FL) has attracted interest for a number of years, giving rise to MPC+FL control schemes. An important advantage of such schemes is that feedback linearizable plants can be controlled with a linear predictive controller with a fixed model. Handling input constraints within such schemes is difficult since simple bound contraints on the input become state dependent because of the nonlinear transformation introduced by feedback linearization. This paper introduces a technique for handling input constraints within a real time MPC/FL scheme, where the plant model employed is a class of dynamic neural networks. The technique is based on a simple affine transformation of the feasible area. A simulated case study is presented to illustrate the use and benefits of the technique.
TL;DR: In this paper, a nonlinear tracking control based on feedback linearization and trajectory planning has been developed for a type of microelectromechanical system, namely, electrostatic micromirrors, in order to extend their stable operation range, enhance the system's performance, and allow controller tuning and system operation to be performed in a systematic manner.
Abstract: This paper is aimed at demonstrating the potential benefits of applying nonlinear control techniques to a type of microelectromechanical system, namely, electrostatic micromirrors, in order to extend their stable operation range, enhance the system's performance, and allow controller tuning and system operation to be performed in a systematic manner. A nonlinear tracking control based on feedback linearization and trajectory planning has been developed. Aspects essential to the implementation, such as the prevention of devices from destruction due to contact, modeling and sensing schemes, the influence of the dynamics of the driving circuit on performance, and the device characterization, have been thoroughly addressed, and practical solutions have been proposed. The experimentation is performed on a setup built with low-cost commercial off-the-shelf instruments and components in a laboratory environment. The experimental results show that the developed control system can achieve stable operation beyond the pull-in position for both set-point and scanning controls.
TL;DR: In this paper, a behavioural decentralized approach that allows an unmanned aerial vehicle (UAV) formation flight to carry out a waypoint-passing mission effectively is proposed. But the objective of the proposed controller is to make each UAV in the formation fly through predefined waypoints while maintaining its distance from other UAVs.
Abstract: This article proposes a behavioural decentralized approach that allows an unmanned aerial vehicle (UAV) formation flight to carry out a waypoint-passing mission effectively. The objective of the proposed controller is to make each UAV in the formation fly through predefined waypoints while maintaining its distance from other UAVs. To perform these two tasks, which can conflict with each other, coupled dynamics of UAVs is considered; this combines the dynamics of all the members in the formation. To apply the behavioural decentralized controller on the basis of the coupled dynamics, a feedback linearization technique with a diffeomorphic transfer map is derived for a three-dimensional UAV kinematics model. A behavioural approach in which the control input is decided by the relative weight of each UAV's desired behaviour is considered, so that the UAVs can react promptly in various situations. Optimization techniques of the gain matrices are also performed to improve the performance of the formation flight ...
TL;DR: A novel multi-crossover genetic algorithm (GA) is proposed to identify the system parameters of a two-link robot and is applied to the feedback linearization control to transfer the system model to a linear model with a nonlinear bounded time-varying uncertainty.
Abstract: In this paper, we propose a novel multi-crossover genetic algorithm (GA) to identify the system parameters of a two-link robot. The resulted system model by the proposed GA is then applied to the feedback linearization control such that the two-link robot system can be transferred to a linear model with a nonlinear bounded time-varying uncertainty. To deal with the uncertainty, a sliding mode control approach is designed to achieve the tracking control. Finally, some simulation results are demonstrated to show the utility of our proposed method.