Abstract: In this paper, we investigate the dc-bus voltage regulation problem for a three-phase boost-type pulsewidth-modulated (PWM) ac/dc converter using passivity-based control theory of Euler-Lagrange (EL) systems. The three-phase PWM ac/dc converters modeled in the a-b-c reference frame are first shown to be EL systems whose EL parameters are explicitly identified. The energy-dissipative properties of this model are fully retained under the d-q-axis transformation. Based on the transformed d-q EL model, passivity-based controllers are then synthesized using the techniques of energy shaping and damping injection. Two possible passivity-based feedback designs are discussed, leading to a feasible dynamic current-loop controller. Motivated from the usual power electronics control schemes and the study of Lee, the internal dc-bus voltage dynamics are regulated via an outer loop proportional plus integral (PI) controller cascaded to the d-axis current loop. Nonlinear PI control results of Desoer and Lin are applied to theoretically validate the proposed outer loop control scheme. The PWM ac/dc converter controlled by the proposed passivity-based current control scheme with outer loop PI compensation has the features of enhanced robustness under model uncertainties, decoupled current-loop dynamics, guaranteed zero steady-state error, and asymptotic rejection of constant load disturbance. Experimental results on a 1.5-kVA PC-based controlled prototype provide verification of these salient features. The experimental responses of a classical linear PI scheme are also included for comparative study.

Abstract: The paper presents a Cartesian impedance controller for flexible joint robots based on the feedback of the complete state of the system, namely the motor position, the joint torque and their derivatives. The approach is applied to a quite general robot model, in which also a damping element is considered in parallel to the joint stiffness. Since passivity and asymptotic stability of the controller hold also for varying damping matrices, some possibilities of designing those gain matrices (depending on the actual inertia matrix) are addressed. The passivity of the controller relies on the usage of only motor side measurements for the position feedback. A method is introduced, which provides the exact desired link side stiffness based on this motor position information. Experimental results are validating the proposed controller.

Abstract: In this paper, we investigate issues in the discrete-time implementation of passivity based control of bilateral teleoperators. The usual scattering formalism which, in continuous time, guarantees passivity for any constant delay, is extended in several important ways to the discrete domain, in particular to the case where communication between the master and slave robots occurs over a packet-switched network. We first show that passivity can be maintained in the face of varying delay and packet loss but that it depends fundamentally on the mechanism used to handle missing packets. Passivity alone is not sufficient to guarantee good performance. Therefore, we also introduce a novel buffering and interpolation scheme which not only preserves passivity but has been shown through simulation and experiments to improve tracking performance and transparency in a single-degree-of-freedom teleoperator system.

Abstract: It is shown how port-based modeling of lumped-parameter complex physical systems (multi-body systems, electrical circuits, electromechanical systems,..) naturally leads to a geometrically defined class of systems, called port-Hamiltonian systems. These are Hamiltonian systems defined with respect to a power-conserving geometric structure capturing the basic interconnection laws, and a Hamiltonian function given by the total stored energy. The structural properties of port-Hamiltonian systems are discussed, in particular the existence of Casimir functions and its implications for stability and stabilization. Furthermore it is shown how passivity-based control results from interconnecting the plant port-Hamiltonian system with a controller port-Hamiltonian system, leading to a closed-loop port-Hamiltonian system. Finally, extensions to the distributed-parameter case are provided by formulating boundary control systems as infinite-dimensional port-Hamiltonian systems.

Abstract: The passivity and passivity breakdown of 304 stainless steel were investigated in 0.25 M Na2SO4solutions of pH 10. The effect of applied potential and the presence of Cl− ions in the electrolyte were also studied. Different electrochemical methods such as open circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS) were used. The results showed that the steel electrode passivates under open circuit conditions and also under potentiostatic control. The rate of passive film thickening under open circuit conditions follows a simple logarithmic law. Addition of Cl− ion shifts the polarization curves in the active direction and above a critical chloride concentration, [Cl− ] ≥ 0.15 M, pitting corrosion occurs and the pitting potential, E pit, decreases linearly with the logarithm of [Cl−]. The addition of sulphate ions to the chloride-containing solutions was found to inhibit the pitting process, and at [SO2- 4] ≥ 0.25 M, a complete immunity to pitting corrosion was recorded. The impedance measurements provided support for film thickening and film breakdown reactions. An equivalent circuit model which consists of a pure resistor, R Ω, in series with a parallel combination of a pure resistor, R p, and a constant phase element, Q, was proposed to describe the electrode/electrolyte interface. The passive film thickness was found to increase with applied potential up to a critical value of 0.3 V. At higher voltages, breakdown of the passive film occured.

Abstract: A methodology is presented for the development of reduced-order macromodels for multiport passive electromagnetic devices that include embedded lumped elements. The proposed methodology utilizes a discrete state-space model for the electromagnetic device, generated through the application of the finite-element method for the spatial discretization of Maxwell's curl equations. The incorporation of lumped resistors, inductors, and capacitors is effected through the direct stamping of the state-space voltage-current relationship for these elements in the matrices of the generated state-space form of the discrete model. The conditions necessary for the discrete model to be passive are discussed. The subsequent reduction of the discrete state-space model is effected through the application of a Krylov-subspace-based model-order reduction scheme that guarantees the passivity of the generated multiport macromodel, provided that the original state-space model is passive. The proposed methodology is demonstrated and validated through its application for the generation of reduced-order macromodels for a coaxial cable circuit and a microstrip directional coupler circuit.

Abstract: In this paper, the control of switched reluctance motors is approached from a passivity-based control perspective. The proposed controller solves the torque/speed/position tracking problem by exploiting the passivity properties of the machine. The methodology design considers the feedback decomposition of the motor model into one electrical and one mechanical passive systems and is divided into the following three steps: control of the electrical subsystem to achieve current tracking, definition of the desired current behavior to assure torque tracking, and design of a speed/position control loop. The main characteristics of the presented result are: it belongs to the class of control schemes that take into account the saturation effects present in stator windings and, regarding torque generation, it considers the use of sharing functions. The contribution of the paper is threefold: The controller design is developed using energy-dissipation ideas, the mathematical formalization of the current engineering practice of controlling this kind of machines with a cascade approach, and an extension to previously reported passivity-based controllers for electric machines in the sense that Blondel-Park transformability properties are not required.

Abstract: Wave variable controllers can make a force reflecting teleoperator insensitive to communication time delays by encoding information before transmission. They are based on passivity and assume no information about the delays or the environment. However, like most robotic control systems, they model the master and slave devices as passive inertias and ignore amplifier and sensor dynamics. We review these modeling assumptions and show that non-idealities of the mechanisms, actuators, and sensors can violate passivity and impose practical limitations on the wave based controllers. We propose a method for quantifying this activeness and dissipating the corresponding energy to restore passivity.

Abstract: After a basic theory on the passivity condition for the sampled-data system has been reviewed, passivity conditions on each subsystem of haptic simulation have been investigated. In addition, the virtual wall simulation is analytically analyzed with the passivity conditions and derived the previously well known stability condition (b > KT/2 + B). Based on this, we propose a novel energy bounding algorithm for stable haptic interaction control. The proposed energy bounding algorithm restricts the energy that is generated by the zero-order hold within the energy consumable by the physical damping in a haptic device and makes the virtual environment and controller passive. This algorithm, therefore, guarantees the passivity condition of the haptic simulation. While the virtual coupling algorithm restricts the actuator force with respect to the penetration depth, the proposed energy bounding algorithm restricts the change of actuator force and eventually restricts generated energy by the zero-order hold. Therefore, much stiffer contact simulation can be implemented.

Abstract: As very large scale integration (VLSI) circuit speeds and density continue to increase, the need to accurately model the effects of three-dimensional (3-D) interconnects has become essential for reliable chip and system design and verification. Since such models are commonly used inside standard circuit simulators for time or frequency domain computations, it is imperative that they be kept compact without compromising accuracy, and also retain relevant physical properties of the original system, such as passivity. In this paper, we describe an approach to generate accurate, compact, and guaranteed passive models of RLC interconnects and packaging structures. The procedure is based on a partial element equivalent circuit (PEEC)-like approach to modeling the impedance of interconnect structures accounting for both the charge accumulation on the surface of conductors and the current traveling in their interior. The resulting formulation, based on nodal or mixed nodal and mesh analysis, enables the application of existing model order reduction techniques. Compactness and passivity of the model are then ensured with a two-step reduction procedure where Krylov-subspace moment-matching methods are followed by a recently proposed, nearly optimal, passive truncated balanced realization-like algorithm. The proposed approach was used for extracting passive models for several industrial examples, whose accuracy was validated both in the frequency domain as well as against measured time-domain data.

Abstract: We propose a general control framework for multiple mechanical systems interacting with environments and/or humans under coordination requirements The key innovation is the passive decomposition which enables us to achieve the two requirements of such systems simultaneously: motion coordination and energetic passivity of the closed-loop system It decomposes the system dynamics into shape system addressing the coordination aspect, locked system representing overall dynamics of the coordinated system, and dynamic couplings between the locked and shape systems The dynamic couplings can be cancelled out without violating passivity Thus, the coordination aspect (shape system) and the dynamics of the coordinated system (locked system) can be decoupled from each other while enforcing passivity Also, by designing the locked and shape controls to enforce passivity of their respective systems, passivity of the closed-loop system is guaranteed We analyze and exhibit geometry of the passive decomposition and the locked and shape systems

Abstract: We characterize the linear RLC networks for which passivity is preserved even if we take as port variables (v/sub s/, d/dt i/sub s/) and/or (d/dt v/sub s/, i/sub s/) instead of the classical variables (v/sub s/, i/sub s/) representing the external port voltage and current, respectively. This characterization is given in terms of an order relationship between the average electric and magnetic energies stored in the circuit. We apply this result to the problem of power shaping stabilization, a methodology recently proposed as an alternative to the more standard energy-shaping technique.

Abstract: We investigate the discrete-time implementation of passivity-based control of bilateral teleoperators. The usual scattering formalism which, in continuous time, guarantees passivity for any constant delay, is extended in several important ways to the discrete domain, in particular to the case where communication between the master and slave robots occurs over a packet-switched network. We first show that passivity can be maintained in the face of varying delay and packet loss but that it depends fundamentally on the mechanism used to handle missing packets. Passivity alone is not sufficient to guarantee good performance. Therefore, we also introduce a novel buffering and interpolation scheme, which not only preserves passivity but has been shown through simulation and experiments to improve tracking performance and transparency in a single-degree-of-freedom teleoperator system.

Abstract: With the increasing operating frequencies and functionality in modern designs, the resulting size of circuit equations of high-frequency interconnect and microwave subnetworks are becoming large. Model-order reduction-based algorithms were recently suggested to handle the solution complexity of such circuits. The major objectives in state-of-the-art model-reduction algorithms are: 1) achieving accurate and compact models; 2) numerically stable and efficient generation of models; and 3) preservation of system properties such as passivity. Algorithms such as PRIMA generate guaranteed passive reduced-order models for large interconnect circuits described by RLC type of circuits. However, with the diverse technologies and complex geometries, it is becoming prevalent to describe some of the embedded linear modules in terms of state-space equations. In this paper, we show how to extend the scope of PRIMA-type first-level reduction algorithms for simultaneous reduction of combined circuits containing both RLC interconnects and embedded modules described by general passive state-space equations, while preserving the passivity of the resulting reduced-order model. Necessary formulation, proof of macromodel passivity, and validation examples are given.

Abstract: In this paper we present a controller synthesis approach for elastic systems based on the mathematical concept of passivity. For nonlinear and linear elastic systems that are inherently passive, ro...

Abstract: This paper develops new classes of CDMA power control designs by exploiting passivity properties of a gradient-type algorithm proposed in the literature. The new control algorithms offer further design-flexibility, which can be exploited for improved performance and robustness. In our first design, we extend the base station algorithm with Zames-Falb multipliers which preserve its passivity properties. In our second design, we broaden the mobile power update laws with more general, dynamic, passive controllers.

Abstract: We examine the passivity and stability of quasi-static partial element equivalent circuit (PEEC) models. The impact of inaccuracies in the computed partial element values is considered as a possible source of time domain instabilities. Our analysis shows how existing partial element calculation routines, analytical and numerical, and the use of poor mesh generators can introduce large errors in partial element values. We also show how this affects the passivity and stability of the PEEC model. Theoretical constraints for passivity are derived which depend on accuracy of partial element values. The conditions are verified by performing practical PEEC model analysis.

Abstract: In this paper we study on the passivity of one degree-of freedom flexible master-slave manipulators (FMSM) with symmetric bilateral control. First, we derive dynamic equations of the FMSM by means of the Hamilton's principle. Second, when applying the symmetric bilateral control to the FMSM, we prove the passivity in the positioning operation by introducing a Lyapunov function related to the total energy. Finally, we also prove the passivity in the neighborhood of the desired state in the pushing operation to an environment.

Abstract: The application of the passivity theory to the radio-frequency (RF) power-amplifier (PA) linearization problem leads to a new structure that is capable to being built completely with analog circuitry. In this paper, the basis of the passivity (or hyperstability) theory are revised and applied to the linearization of an RF power amplifier, proposing the resulting linearizer structure and experimenting with it from simulations based on the RF PA experimentally validated by Saleh and from a real model of a Class A PA operating at 28 GHz.

Abstract: This work presents a fast technique for testing and enforcing passivity of linear macromodels characterized by a large and sparse structure. An optimized algorithm is proposed for the computation of the imaginary eigenvalues of the associated Hamiltonian matrix, which are iteratively perturbed until passivity is enforced. Each iteration of the proposed scheme requires a small computational cost that scales only linearly with the size of the problem.

Abstract: This paper investigates vision-based robot control based on the passivity for the three dimensional target tracking. Firstly, the fundamental representation between the moving target object and the camera is derived from the relation among the three coordinate frames. Next, we consider the observer which is reproduced from the fundamental representation of relative rigid body motion just as Luenberger observer for linear systems. Then, the relationship between the estimation error in the 3D workspace and in the image plane is established. Secondly, we derive the passivity of the dynamic visual feedback system by combining the passivity of both the visual feedback system and the manipulator dynamics. The stability via Lyapunov method for the full 3D dynamic visual feedback system is discussed based on the passivity. Finally, the L/sub 2/-gain performance analysis for the disturbance attenuation problem is considered via the dissipative systems theory.

Abstract: We present circuit topologies and fitting methods that accurately represent on-chip transformers over a frequency sufficient for cellular and PCS circuit analysis. Starting with an S-parameter matrix, obtained through measurement or electromagnetic (EM) simulation, we find an equivalent lumped-element circuit model with minimum fitting error. Consideration is made for the passivity of the model. Examples are shown that include measurements, EM simulation, and equivalent circuit models.

Abstract: We present a frequency-domain solution to the sampled-data passivity problem. Our analysis is exact in that we take into account the intersample behavior of the sampled-data system. We use frequency-response operators and derive a necessary and sufficient condition on the discrete controller that renders a passive closed-loop system. We then find a finite-dimensional system whose closed-loop passivity is equivalent to that of the original one, thus solving the sampled-data passivity synthesis problem. Computations of the equivalent system are carried out in the frequency domain.

Abstract: The nonlinear dynamk model of the underactuated mechanical systems is buillt with Lagrangian method Several properties of the system model such as the positive definite symmetric inertia matrix and the passivity are analyzed A passivity-based control method is proposed for the underactuated mechanical system The unlderactuated doublependulum- type overhead crane system is used to validate the proposed control algorithm Simulation rlesults illustrate the complex system dynamics of the double-pendlulum-type overhead crane and the validity of proposed control algorithm

Abstract: With coordinated passivity techniques, the excitation and steam-valving control for generator are proposed to make rotor angle and voltage stable. By backstepping techniques steam-valving control is designed, and excitation control is achieved based on coordinated passivity. So the feedback passivity of whole system is obtained and the closed-loop system is asymptotically stable. Since the controller design is based completely on the nonlinear dynamic system without any linearization, the nonlinear property of the system is used for nonlinear robust controller design. Simulations have proved the effectiveness of the proposed control law.