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An adaptive integrator backstepping control law for magnetically actuated earth-pointing satellite is proposed. The equation for required magnetic control torque along the three body axes is shown with the proposed control law. The stability of the system about the origin is proved and it is uniformly asymptotically stable. A time variant uncertainty in the dynamics of spacecraft is considered. The detailed implementation of the control law is developed and presented. In order to show the efficacy of the proposed control law, the simulation is given for the tracking problem of the satellite under time variant uncertain disturbance.

Estimating a dynamic model of a servo actuator often has to be done on the basis of noisy closed-loop experiments in which feedback is controlling the servo actuator. The presence of feedback complicates the estimation procedure due to strong correlation of control signals with disturbances present on the servo system. This paper shows how information on the feedback controller can be used to equalize the effects of disturbances on the control signals and estimate low order models of the actuator dynamics. The approach uniquely relies on a fractional representation of the feedback controller and a coupled least squares optimization problem to estimate an actuator model. Motion control experiments of a servo actuator in a Linear Tape Open drive operating under feedback will be used to illustrate the effectiveness of the procedure and will show the possibility to estimate low order servo actuator models.

Date of Conference: 24-29 August 2014 Conference Name: 19th World Congress of the International Federation of Automatic Control, IFAC 2014 In this paper we propose a coupled model for healthy and cancerous cell dynamics in Acute Myeloid Leukemia. The PDE-based model is transformed to a nonlinear distributed delay system. For an equilibrium point of interest, necessary and sufficient conditions of local asymptotic stability are given. Simulation examples are given to illustrate the results.

In this work we study the problem of rope sway dynamics control for elevator systems, with time-varying rope lengths. We formulate this problem as a nonlinear control problem and propose nonlinear controllers based on Lyapunov theory for time-varying systems. We study the stability of the proposed controllers, and test their performances on a numerical example.

In this work, two high order sliding mode observers under cascade form are proposed in order to estimate the important states and inputs affecting the lateral dynamics of two-wheeled vehicles. The first observer is based on a vision system and is used to estimate the lateral velocity of the vehicle. This velocity is considered as an additional measure for the second observer which is designed to estimate the tire forces, the roll angle and torque applied to the handle-bar. The main contribution of this work is the estimation of the tire forces even with the variation of the longitudinal velocity and without the prior knowledge of the pneumatic coefficients.

This paper develops a slip angle estimation method using measurements of lateral acceleration and yaw rate. A unique model for slip angle estimation is developed by combining velocity kinematics, yaw dynamics, and lateral translational dynamics, so as to avoid sensor drift and parameter variation effect. The model is used in designing a state estimator to estimate slip angle, which compensates slip angle prediction error using the measurements of lateral acceleration and yaw rate. Experimental performance verification of the proposed slip angle estimation scheme is presented.

The paper discusses a gyro-moment stabilization system of a flexible spacecraft (FS). The possibility of using a proportionally-differential algorithm (PD) for attitude control employing the single-gimbals control moment gyroscopes (gyrodines) is investigated. Specifics of this type of control at “infra-low” (0.01–0.1 Hz) frequencies of the object's flexible oscillations are studied. The questions of designing an additional gyro-stabilization subsystem at weakly damped and low-frequency flexible oscillations are considered. An adaptive regulator is suggested for FS that is described either by a not exactly defined mathematical model or by a non-stationary model.

This paper presents a dynamic model and a class of terminal sliding mode control (TSMC) for two-link flexible manipulators with noncollocated feedback. With the assumed mode method, the closed form dynamic model of two-link flexible manipulators is derived by using the Lagrangian approach. The TSMC technique is used to design the controller. The mode coordinate vectors of flexible manipulators are computed by noncollocated feedback. The proposed TSMC guarantees that the output tracking error converges to zero in finite time under external disturbance. Numerical simulation results of two-link flexible manipulators are provided to verify the effectiveness of the proposed control scheme.

In this study, a novel cascaded robust terminal sliding mode control approach is developed for robotic manipulators including actuator dynamics. The proposed approach can achieve finite-time stability in the presence of arbitrary uncertain mechanical and electrical parameters of the robot model. Corresponding stability analysis is presented to lay a foundation for analytical understanding in generic theoretical aspects and safe operation for real systems. An illustrative example is bench tested to validate the effectiveness of the proposed approach.

We consider a class of multi-link mechanical systems arising from the dynamics of multi-segmental animal locomotion in a two dimensional plane. As revealed in the earlier paper, when the head link is constrained along a specified direction, the remaining links can be fully controlled by the corresponding joint torques to achieve an autonomous locomotion in natural oscillation. In this paper, we further consider a free motion without the head constraint. An additional degree of freedom representing the motion direction is thus induced, which motives a novel underactuated control approach.

Dynamic emission models for Diesel engines are important for future engine development. Emission formation takes place in the cylinder, while the emissions are usually measured downstream the exhaust pipe. Besides operation point dependent gas transportation delays the emission sensors themselves possess a significant dead time and sensor time constant varying for different measured quantities. These sensor individual dynamic measurement characteristics complicate the chronological assignment of cause and effect in emission modelling. Therefore the dynamic characteristics of a NO x , a micro soot sensor and an opacimeter are investigated. Models for the measurement dynamics are derived to separate the measurement dynamics from the engine dynamics. Hence excitation signals which strongly excite the emission formation and only weakly excite the intake and exhaust system are presented. Model results for the measurement dynamics are shown and validated with testbed data.

Lyapunov guidance law based on error dynamics is proposed to perform observation missions. A new guidance law is designed in the consideration of the characteristics of distance error dynamics. Lyapunov stability theorem is used to analyze the guidance law. The turning direction is related to the difference between the Line-of-sight rate and the heading angle of each UAV. Linear-quadratic regulator is used to design a controller for a linear six degree-of-freedom UAV system. Numerical simulations are performed to validate the performance of the proposed guidance law, and are compared with that of pure error dynamics-based guidance law.

The non-isothermal continuous stirred tank reactor (CSTR) is a classical yet complex case study of nonlinear dynamical systems. Power-shaping control is a recent approach for the control of nonlinear systems based on the physics of the dynamical system and it rests on the formulation of the dynamics in the Brayton-Moser form. The Brayton-Moser formulation of the non-isothermal continuous stirred tank reactor is investigated based on physical considerations on the system.

In this paper, we present a novel scanning probe microscope (SPM) lateral dynamics modeling technique that exploits the SPM's topography measurement capabilities. SPMs are key tools in the advancement of nanotechnologies, but their speed is limited due to a number of key issues, including dynamic effects. In order to facilitate high-speed SPM operation, these dynamic effects should be accurately modeled, thus enabling the application of feedforward and feedback control methodologies. The main contribution of this study is the development of a modeling method that uses the SPM probe-sample interaction (topography) signal obtained by scanning a standard calibration sample to develop a transfer function model of the SPM dynamics. The novelty of this method is that it exploits the SPM probe-sample interaction signal to model the dynamics as opposed to external sensors. The method is presented in detail and experimentally verified using a commercial atomic force microscope (AFM).

This paper describes the black-box identification of the rear wheel slip dynamics of a racing motorbike equipped with an electronic throttle. The system's response to two different inputs is studied: throttle and spark advance. After the description of the experimental setup, issues regarding signal processing and data analysis are discussed. Two types of tests, step and frequency sweep responses, are performed to evaluate the differences between the available actuation methods. The experimental data analysis allows to derive a model useful for traction control design and shows that throttle action is only marginally slower than spark advance.

Non-conventional principles of locomotion for mobile robotic systems are considered, namely, snake-like locomotion of multilink systems and control of motion by means of moving internal masses. These motions are possible in the presence of external resistance forces such as Coulomb's dry friction or viscous resistance. Optimal periodic motions are obtained that correspond to the maximal average velocity of the system as a whole. Evaluation of the maximal possible velocity is important for the overall estimation of operational properties of the robotic systems under consideration.

We propose a new method of estimating the 6 DOF(Degree-of-Freedom) motion of a unknown moving object using monocular image sequences. By using the parameters of the homography matrix, we can describe the 6 DOF dynamics of a moving object as a linear time-varying system. Based on this dynamic model, we design a 6DOF motion estimator of the object. We also show that the observability condition of the proposed 6 DOF estimator is much milder than that of the bearings-only tracking methods. Then, we demonstrate the performance of the proposed estimator through various simulation results.

The robust identification of nonlinear frictional dynamics constitutes a significant challenge for the model based friction compensation in advanced control of electro-mechanical drives. This paper discusses the frictional phenomena in pre-sliding and gross sliding regime described by the advanced General-Maxwell-Slip friction model and proposes a robust identification approach to determine their distributed parameters. The nonlinear dynamics of a drive chain with multiple frictional surfaces is described. The appropriate control signals are designed to excite the friction dynamics in both pre-sliding and sliding regimes. The estimation of friction parameters relies on the recursive least square (RLS) technique with a suitable set of regressors. The identified model is compared with experimental data and applied in a tunable framework for the model based friction compensation.

In this paper, a novel force tracking impedance control strategy is presented in which target stiffness is varied on-line to regulate the desired contact force without any knowledge of the environment. Humans can control contact force by adjusting their arm stiffness. The contact force can be either increased by making one's arm stiffer or decreased by reducing the arm stiffness. Furthermore, humans can keep the force tracking error within a certain range without any knowledge of environmental parameters as long as how much force they exert on the object is known to them. Analogously, the proposed control scheme achieves a contact force regulation control by adjusting the target stiffness of the impedance control. The new force tracking impedance control scheme does not require estimating environment stiffness or locations since the controller is adapted only based on the previous force tracking error between the desired and real contact force. Stability of the proposed scheme is discussed with a quadratic Lyapunov function. Extensive simulation studies with a 7 degree of freedom (DoF) robot manipulator using full arm dynamics are conducted to demonstrate the validity of the proposed scheme.

This paper presents a solution to the boundary stabilization of a symmetric composite laminated plate in free transverse vibration. The symmetric composite laminated plate dynamics is presented by a linear fourth order partial differential equation (PDE). A linear control law is constructed to stabilize the plate. The control force consists of feedback of the velocity at the boundary of the plate. The novelty of this article is that it is possible to stabilize asymptotically a free transversely vibrating symmetric composite laminated plate with simply supported boundary condition via boundary control without resorting to truncation of the model.

This paper presents a new control allocation design method for overactuated linear systems with internal dynamics and input constraints. The control inputs are designed to implement constrained control allocation and guaranteed stability of the closed-loop system. An LMI-based sufficient condition is provided to solve the control allocation problem. The proposed approach is demonstrated by a linear tailless aircraft model.

This paper presents the results of the parameter estimation procedure for the primary circuit dynamics of a VVER-type nuclear power plant. The model structure is a low dimensional lumped nonlinear model published previously in Fazekas et al. [2007a]. The parameter estimation method uses the modular decomposition of the system model for obtaining physically meaningful initial parameter estimates. The final parameter estimates are computed using the integrated model.

A control profile is generated which suppresses one or more resonant dynamics in a flexible dynamic system. This control profile can be used as a velocity profile, or as a shape filter to an arbitrary control command. The robustness can be arbitrarily improved, which brings about a smoother profile. The technique can be applied to both open-loop and closed-loop systems.

This paper provides an overview of the derivation of a dynamic model of a Load-Haul-Dump (LHD) vehicle. The model is derived using Lagrangian Dynamics and makes use of a simplified tyre model in an attempt to include the effect of basic tyre dynamics. Simulation results obtained from the vehicle model are provided and the results discussed and analysed.

In this article the control problem of a micro-actuator (μ – A is considered. The μ – A is composed of a micro-capacitor, whose one plate is clamped while its other flexible plate's motion is constrained by hinges acting as a combination of springs and dashpots. The distance of the plates is varied by the applied voltage between them. The flexibility of the moving plate coupled to the dynamics of the plate's rigid-body motion results in an unstable, nonlinear system of distributed nature. Utilization of FEM can approximate the μ – A dynamics nonlinear-PDE to a finite nonlinear-ODE. The nonlinearity stems from the plate's rigid-body motion, while all flexibility effects are considered as additive linear-terms. A controller composed of: a) a feedforward term for regulation at selected setpoints, and b) a constrained finite time optimal controller to handle any deviations from the equilibrium is synthesized. Simulation studies are used to investigate the efficacy of the suggested controller.

Vehicle dynamics control systems require a close monitoring of the associated sensors since an erroneous intervention of the controller due to faulty measurements may have fatal consequences. Hardware failures with an immediate impact on sensor signals are detected by build-in sensor tests in connection with a plausibility check of the electrical signals. Slowly growing sensor offsets on the other hand require model based monitoring. Actually simple stationary models are used to detect these slow changes. Simplicity of the models, however, must be compensated for by an excessive exception handling in order to avoid false alarms due to non-valid models. In this paper, an invariant relation for the signals capturing vehicle lateral dynamics is derived. Based on this relation a novel scheme for vehicle lateral dynamics sensor monitoring is proposed which drastically reduces the necessary exception handling and which keeps up simultaneously with the advantage of simple models.

Solving a tracking problem does not always give desired results even when the adaptive control methods are used. Some difficulties may occur when the apriori assumptions laid down for the problem solution are not satisfied. One of the serious issues is the existence of unmodeled dynamics in the tracking problem. The proposed solutions are mainly based on robustification of the adaptation law. In this paper we propose to reduce the effect of unmodeled dynamics using the MRAC control law modification so that the standard adaptation law ensures the sufficiently small tracking error.

In this paper, we propose a new chaotic itinerant model of mode transition dynamics in human circulatory systems. An essential emphasis of the model is on autonomous mode transition based on chaotic itinerancy of large-scale nonlinear systems. It is shown that the model possesses some important properties observed in the circulatory systems, such as mode transition and its controllability.

Devil stick is a kind of juggling as to control a floating stick (center stick) by hitting or pushing with other sticks (hand sticks). Our purpose is to achieve propeller motion that the center stick rotates continuously by only pushing with one hand stick. While a position of the cent er stick is controlled by output zeroing with suitable output function which is derived from a good jugglers motion, an angular velocity is governed by unstable zero dynamics. From an analysis of this zero dynamics, it is shown that the angular velocity is stabilized by changing the contact point of sticks.

This paper proposes a new method for estimation and suppression of disturbance with unknown dynamics. Based on a well-known Independent Component Analysis technique and its generalization to a dynamical mixture case, the method makes it possible to extract disturbance signals from signals to be controlled, and then suppress their effect by applying a suitable feedback. The effectiveness of the method is confirmed through numerical simulation.

A method for reducing the angular momentum of a satellite by giving two-dimensional external impulsive torques induced by thrusts is proposed, based on the zero dynamics formulation. This method has an advantage in that the direction of thrusts is limited. The torque is assumed to be constant during thrusting and its duration is determined so that the total amount of thrusts becomes equivalent to the integration of the continuous feedback torque based on the zero dynamics formulation. In accordance with the period of the rotational motion of a satellite, thrust timing is selected to reduce effectively the angular velocities. A simulation result shows that the rotational motion is successfully reduced around all axes even if the impulsive torques affecting the satellite are only two-dimensional torques.

This paper presents a study on two kinematic structures for dynamically stable biped locomotion. The two legs, each with three degrees of freedom, are connected through a rigid waist. The dynamics of both structures is modelled by partitioning the six dof kinematic chain in a 3 dof supporting leg and a 3 dof balance leg. A low complexity model is obtained by simplifying the dynamics of the balance leg not accounting for rotational dynamics. It is shown that the overall model produces good results under the point mass assumption for each link and a standard robust control algorithm.

Mathematical models of a gyroplane rotor have been carried out. Their approximate analytical solutions have been obtained. Software allowing one to simulate and study a rotor dynamics has been created. Major physical features on the forced flexible oscillations of the rotor have been investigated. The results obtained have successfully been applied to design the A-002 gyroplane rotor.

This paper presents a methodology for designing a nonlinear longitudinal controller for an F-16 aircraft using a linear parameter varying (LPV) technique. The controller is designed by deriving a LPV model from the nonlinear equations of the F-16 longitudinal dynamics. Then a number of linear matrix inequalities (LMIs) are solved for the control parameters. The simulation results demonstrate that the LPV model describes the dynamics of the F-16 longitudinal motion over the desired flight envelope quite accurately. The proposed controller is applied to the nonlinear model of the F-16 longitudinal dynamics. The controller is tested for different scenarios corresponding to different longitudinal motions of a real aircraft. The simulation results demonstrate that the control objectives are achieved over the desired flight envelope and within the control limit constrains.

On the basis of a standard linearized single-track model for yaw rate and lateral speed (or sideslip angle) vehicle dynamics a new feedback control law is proposed for the front steering angle which makes use of yaw rate, lateral acceleration and longitudinal speed measurements. It generalizes the controller proposed by Ackermann (Ackermann, 1990) and achieves the decoupling of the yaw rate regulation dynamics from the lateral speed dynamics. In the case of four wheel steering vehicles a centralized decoupling controller is also proposed which achieves the decoupling of lateral speed dynamics from yaw motions, and allows for lateral speed regulation as well.

In this work we consider the problem of rest-to-rest motion for planar flexible multi-link manipulators. We introduce a simple idea permitting the cancellation of end-effector residual vibration when reaching a desired angular equilibrium position, in a fixed travelling time. No internal elastic damping effect is considered and the structure of the control is simply the sum of feedforward and joint feedback terms. The new approach concerns the computation of the feedforward control, which is based on backward integration of the elastic dynamics, starting from a rest position of the flexible arms. For fast rest-to-rest motion, the feedback compensator fails to drive the system states along the desired trajectories, due to the relatively large initial elastic error. To overcome this limitation, proper joint motion is planned between the desired initial and final positions through optimization techniques. This scheme is validated via numerical tests on a two-link planar manipulator

The concept of platoon stability is investigated for a convoy of vehicles, each having a local controller which can use information about the motion of those both behind and ahead of it. Conditions on the control parameters are obtained, such that platoon stability can be ensured while simultaneously enabling the intervehicular spacing to be kept independent of velocity. Simulation results, illustrating the response of the convoy to a change in velocity of the lead vehicle, are also presented.

In this paper model based fault tolerant estimation of vehicle lateral dynamics is studied. The core of the study is the development of an adaptive observer that is used for the estimation purpose in the fault-free situation. To be tolerant to possible sensor faults, different observers/estimator are then proposed, which deliver an estimation of lateral dynamics even if some sensors fail. Finally, the estimation performance of the proposed fault tolerant estimation system is studied.

In this paper a condition is given for Internal Model Control (IMC) anti-windup structures to be robustly L 2 stable with respect to H ∞ bounded model uncertainty and in presence of input saturation. This condition can be suitably used for the design of robust IMC anti-windup controllers that make up the best H ∞ approximation to “perfect” linear control among all controllers guaranteeing L 2 stability in presence of actuator saturation.

Recent anatomical studies of extraocular muscles (EOM) demonstrate the stability of muscle paths. This is due to the fact that each rectus EOM passes through a pulley consisting of an encircling ring or sleeve of collagen. In this paper, the EOMs are modeled using the Hill type musculotendon complex and the effect of extraocular pulleys are studied. The model proposed by Martin and Schovanec in 1999, for horizontal eye movement has been used as a basic starting point. The extraocular pulleys are then introduced and analyzed mainly to study how Listing's law is enforced and how it implements an oculomotor plant which appears commutative to the brain.

Neural network models and mass balance equations were used for the simulation of a converter at a nickel smelter. The model achieved a more consistent iron content that is close to the target content of the market matte. Operating data were collected and mass balance equations were used to re-construct the masses to be used for the purpose of model identification. The neural network models predicted the rates of elimination of the elemental masses in the matte, which were then used in the mass balance equations to predict the elemental masses in the matte of the converter.

A spacecraft attitude control simulation must be completed by a excitation source on its angular sensors to close and test its control loop. To provide this excitation, an angular motion simulator is necessary in the loop. However, this device has its own dynamical characteristics, which is unpredicted on the original control project and it can cause important changes in the control loop performance. In order to minimize those effects on the simulation loop, this work presents a proposition of a digital compensator design to cope with such undesirable dynamics, and a method to evaluate the obtained models.

In this paper a robust controller design task for longitudinal and lateral dynamic of non-identical autonomous road vehicles is considered. In order to use identical controllers for different vehicles the varying parameters are regarded as unstructured model uncertainties. How unstructured model uncertainties are described and how they are taken into account during the controller design process is shortly presented. The used control concept for plants with model uncertainties in form of a standard H_control task is described. The resulting longitudinal and lateral control laws for nonidentical vehicles are discussed concerning the varying vehicle parameters. The first practical results with respectively one control law for longitudinal and lateral dynamic of non-identical autonomous vehicles are presented. It is shown that through the appropriate choice of design parameters, varying vehicle dynamics can be taken into account without substantial losses regarding accuracy and dynamics.

We investigate the simplest dynamical models of a formation of spacecraft in orbit, and develop the stability conditions for the equivalent virtual structure. These stability conditions represent a first step towards an understanding of how to control these formations. The concept of generalized formation joint is also introduced, using multibody dynamics concepts, and its use for formation reconfigurations is also demonstrated. Finally, the concept of the virtual structure is extended to swarms with stochastic distributions.

The piezoelectric actuator is a well-known device for managing extremely small displacements. In the behavior of a piezo-actuated system the actuator dynamics play a dominant role. Therefore, in order to be able to design a high performance model-based controller the actuator dynamics must be taken into account in the system model. A physical model is derived, where the hysteresis effect is represented by a first-order nonlinear differential equation. Using the inverse hysteresis operator a mixed feedback/inverse controller is developed and applied in practice.

The paper addresses the motion planning problem (MPP) arising in manipulation tasks where rigid bodies may roll on each other without slipping. In the planar case, where both the kinematics and dynamics of the system are considered, the MPP can be solved without quasi-static approximations. This result follows from the integrability of the kinematic constraints and the differential flatness property which allows to easily parameterize the set of feasible trajectories of the system. An extension to a three dimensional example is also presented using the Liouvillian property of the corresponding kinematic model.

In this paper, the problem of stabilising the position and heading of a ship is considered. The problem is dealt with in the case of a single-thruster (under-actuated) vehicle, subject to external forces due to the wind and the current. The set of the admissible steady-state conditions is studied, and a control law which exactly linearizes the I/O behaviour of the ship is designed. The zero dynamics (which can be interpreted as the dynamics of the ship attitude) are locally stable about a subset of steady-state conditions.

The problem of the robust digital controller design to form the desired transients for aircraft longitudinal motion is discussed. The design method based on the formation of two-time scale motions in the closed loop system is used. Assuming a small sampling period, robust decoupled output tracking with desired continuous-time dynamics is accomplished under conditions of incomplete information about varying parameters of the system and unknown external disturbances. Simulation results are presented.

This article describes the design and experimental validation of a new three-degree-of-freedom flexible arm. This arm was built with light links, has most of its mass concentrated at the tip, and uses a special mechanical configuration to approximately decouple radial tip motion from angular tip motions; i.e. the first actuator produces an azimuth movement, the second actuator produces a cenital movement and the third one produces an approximately radial movement. The compliance matrix can be used to model the oscillations of the structure. The proposed mechanism shows some advantages to control the arm: first, a lumped masses model with only one mass concentrated at the tip can be used to characterize the system, avoiding the use of distributed masses models; second, because of these simple dynamics, minimum sensing effort is required (only motor and tip measurements) and the use of complex observers is avoided because the state of the system is obtained directly. Experimental identification and validation are presented

Eye movement systems are ideal for studying human control of movement since they are of relatively low dimension and easier to control than other neuromuscular systems. In this paper, a model of the ocular motor plant is developed for the purpose of simulating saccadic eye movement. The system that is presented incorporates muscle mass, general nonlinear musculotendon dynamics and activation dynamics that couple neural controls that are appropriate for saccadic movements to the muscle mechanics. Eye position, velocity and muscle tension are illustrated by numerical simulation of the model. By scrutinizing the trajectories of the eye movements it is possible to infer the effects of motoncuronal activity, deduce the central nervous system's control strategy, and systematically observe the effects of perturbations in the controls.