Passivity-based Control Approach Research Articles

Hybrid Nonlinear Passivity-Based Control Approach to Magnetic-Impulsive Spacecraft Attitude Regulation

This paper proposes two novel passivity-based control design frameworks for hybrid nonlinear time-varying dynamical systems involving an interacting amalgam of continuous-time and discrete-time dynamics whose dynamical properties evolve periodically over time. In this regard, the hybrid Kalman–Yakubovich–Popov conditions are employed in tandem with the passivity theorem to construct a three-step control design algorithm to render closed-loop dynamics stable. The proposed control architectures are subsequently exploited to regulate the attitude motion of spacecraft with magnetic and impulsive modes of operation. Practical considerations involved in implementing the proposed hybrid algorithms are then discussed in detail. Simulation results show significant improvement in the performance of the attitude control system in terms of system response, robustness, and the required magnetic and impulsive control usage as compared to a hybrid linear approach.

Passivity-Based Nonlinear Control Approach for Efficient Energy Management in Fuel Cell Hybrid Electric Vehicles

Passivity-Based Nonlinear Control Approach for Efficient Energy Management in Fuel Cell Hybrid Electric Vehicles

Stabilization of Physical Systems via Saturated Controllers With Partial State Measurements

This article provides a constructive passivity-based control (PBC) approach to solve the set-point regulation problem for input-affine continuous nonlinear systems while considering bounded inputs. As customary in PBC, the methodology consists of two steps: energy shaping and damping injection. In terms of applicability, the proposed controllers have two advantages concerning other PBC techniques: 1) the energy shaping is carried out without solving partial differential equations and 2) the damping injection is performed without measuring the passive output. As a result, the proposed methodology is suitable to control a broad range of physical systems, e.g., mechanical, electrical, and electromechanical systems, with saturated control signals. We illustrate the applicability of the technique by designing controllers for systems in different physical domains, where we validate the analytical results via simulations and experiments.

Payload trajectory tracking of a 5-DOF tower crane with a varying-length hoist cable: A passivity-based adaptive control approach

Payload trajectory tracking of a 5-DOF tower crane with a varying-length hoist cable: A passivity-based adaptive control approach

A Passive-Constrained Observer and Controller Applied to an In-Wheel Synchronous Machine Implemented on a Fixed-Point DSP

In this paper, we describe a passivity-based control (PBC) approach for in-wheel permanent magnet synchronous machines that expands on the conventional passivity-based controller. We derive the controller and observer parameter constraints in order to maintain the passivity of the interconnected system and thus improve the control system’s robustness to varying loads and plant parameters. The advantages of the proposed PBC technique are demonstrated in contrast with conventional PBC. The control technique is implemented on an electronic development board equipped with a fixed-point digital signal processor and coupled to a gallium nitride voltage source inverter and 350 W electric machine. Test bench results and numerical simulations in Matlab-Simulink demonstrate the control performance and behaviour under varying loads and parameters.

Tuning Rules for Passivity-Based Integral Control for a Class of Mechanical Systems

This manuscript introduces a passivity-based integral control approach for fully-actuated mechanical systems. The novelty of our methodology is that we exploit the gyroscopic forces of the mechanical systems to exponentially stabilize the mechanical system at the desired equilibrium even in the presence of matched disturbances; additionally, we show that our approach is robust against unmatched disturbances. Furthermore, we provide tuning rules to prescribe the performance of the closed-loop system. We conclude this manuscript with experimental results obtained from a robotic arm.

On control of voltage-actuated piezoelectric beam: A Krasovskii passivity-based approach

This paper presents a new passivity property for distributed piezoelectric devices with integrable port-variables. This novel passivity-based control approach is suited for dissipative systems. We present two new control methodologies by exploiting the integrability property of the port-variables. The derived controllers have a Proportional-Integral (PI) like structure and are shown to asymptotically stabilize the piezoelectric devices. Finally, simulation results are presented for both controllers for a PZT-4 piezoelectric device.

Path-Tracking Considering Yaw Stability With Passivity-Based Control for Autonomous Vehicles

In this paper, a new passivity-based control approach is designed to improve the robustness and stability of autonomous vehicles in performing path-tracking tasks. A port-Hamiltonian model is a special geometric structure and provides a systematic and insightful framework to describe many physical systems from an energy perspective. The passivity-based control establishes a new and simple structure to achieve the path-tracking task by the port-Hamiltonian structure. Firstly, the path-tracking error system is transformed into a port-Hamiltonian system with the perturbation. The energy-shaping method is utilized to ensure the asymptotic stability, and the stability proof of the closed-loop, path-tracking error system is given. The proposed real-time, passivity-based controller is directly dependent on the passive outputs, which is robust to parameter uncertainties caused by load changes. Moreover, the control performance of steering control will be degraded when the steering angle is saturated. The yaw-moment control is introduced to enhance the driving safety. In the wheel torque distribution, an optimization-based control allocation is designed to minimize the sum of tire loads and to make them more evenly distributed to each tire. Finally, simulations are implemented in MATLAB/Simulink and CarSim co-simulation to demonstrate the effectiveness of the designed strategy under different driving conditions.

Passivity-based hierarchical sliding mode control/observer of underactuated mechanical systems

This paper investigates a passivity-based hierarchical SM control (PBHSMC) approach to solve the trajectory tracking issue of a special class of UMSs using unmeasured states and in presence of both unmatched and matched perturbations. First, a passivity-based SM observer (PBSMO) is designed for quick estimation of states in the UMS. Then, we develop a nonlinear two-layer switching surface using feedback passivation. The passivation-based approach ensures global asymptotical convergence of tracking error on the switching surface with the discontinuous term. Moreover, we develop an SMC law that can satisfy reaching mode and sliding mode conditions. Finally, to illustrate the performance of theoretical results, the developed control scheme is assessed by numerical simulation of two case studies including flexible-joint manipulator (FJM) and underactuated surface vessel (USV) systems. The simulation results indicate the superiority of the PBSMO-based PBHSMC scheme over the conventional SMO-based HSMC in suppressing unwanted oscillations of link, low tracking error and overshoot, short settling time, smooth and small control efforts, and also more accurate estimation of state variables with less chattering.

An IDA-PBC Design with Integral Action for Output Voltage Regulation in an Interleaved Boost Converter for DC Microgrid Applications

This paper describes the output voltage regulation control for an interleaved connected to a direct current (DC) microgrid considering bidirectional current flows. The proposed controller is based on an interconnection and damping passivity-based control (IDA-PBC) approach with integral action that regulates the output voltage profile at its assigned reference. This approach designs a control law via nonlinear feedback that ensures asymptotic stability in a closed-loop in the sense of Lyapunov. Moreover, the IDA-PBC design adds an integral gain to eliminate the possible tracking errors in steady-state conditions. Numerical simulations in the Piecewise Linear Electrical Circuit Simulation (PLECS) package for MATLAB/Simulink demonstrate that the effectiveness of the proposed controller is assessed and compared with a conventional proportional-integral controller under different scenarios considering strong variations in the current injected/absorbed by the DC microgrid.

Bounded inputs total energy shaping for a class of underactuated mechanical systems

AbstractDesigning control systems with bounded input is a practical consideration since realizable physical systems are limited by the saturation of actuators. The actuators' saturation degrades the performance of the control system, and in extreme cases, the stability of the closed‐loop system may be lost. However, actuator's saturation is typically neglected in the design of control systems, with compensation being made in the form of overdesigning the actuator or by postanalyzing the resulting system to ensure acceptable performance. The bounded input control of fully actuated mechanical systems has been investigated in multiple studies, but it is not generalized for underactuated mechanical systems. This article proposes a systematic framework for finding the upper bound of control effort in underactuated systems, based on interconnection and the damping assignment passivity based control approach. The proposed method also offers design variables for the control law to be tuned, considering the actuator's limit. The primary difficulty in finding the control input upper bounds is the velocity‐dependent kinetic energy‐related terms. Thus, the upper bound of velocity is computed using a suitable Lyapunov candidate as a function of closed‐loop system parameters. The validity and application of the proposed method are investigated in detail through two benchmark systems simulations.

Passivity-based control of mechanical systems with linear damping identification

We propose a control approach for a class of nonlinear mechanical systems to stabilize the system under study while ensuring that the oscillations of the transient response are reduced. The approach is twofold: (i) we apply our technique for linear viscous damping identification of the system to improve the accuracy of the selected control technique, and (ii) we implement a passivity-based controller to stabilize and reduce the oscillations by selecting the control parameters properly in accordance with the identified damping. Moreover, we provide an analysis for a particular passivity-based control approach that has been shown successfully for reducing such oscillations. Also, we validate the methodology by implementing it experimentally in a planar manipulator.

Passivity-Based Nonlinear Control Approach for Tracking Task of an Underactuated CMG

This article proposes a passivity-based nonlinear control approach to deal with the tracking task of a control moment gyroscope (CMG), which is an underactuated nonlinear MIMO system with coupled dynamics, where the main goal is the tracking of the unactuated states in a wide range of operation. To overcome this underactuation, the proposed nonlinear controller employs the CMG intrinsic reaction torques. The closed-loop system stability is analyzed by invoking the Lyapunov stability and Matrosov's theorem. Numerical simulations and real-time practical experiments with the real plant are performed to validate the proposed nonlinear controller, as well as its performance is analyzed by contrasting the experiment results with the ones obtained by authors’ previous established nonlinear controllers.

A Swash Mass Pendulum with Passivity-Based Control

We propose a mechanical system named swash mass pendulum (SMP) with application in robotics, and we develop a passivity-based control approach. The SMP is a pendulum made of a rigid shaft connected to a pair of cross-shafts where four swash masses can move under the action of servo mechanisms. The control objective is to stabilize the pendulum at a desired rest orientation. The regulation at the desired orientation is obtained via energy shaping that prevents the solution of partial differential equations. The derivation of the control law consists of a) partial feedback linearization under input coupling, b) a proportional plus integral (PI) controller acting on two new passive outputs. The performance of the controller is assessed by both simulations and experimental results, showing the effectiveness of the control design for the novel proposed pendulum.

Controller design, analysis and testing of a three‐phase VSI using IDA–PBC approach

A voltage-source inverter (VSI) is a key component of a distributed generation unit and an uninterruptible power supply. In this study, a three-phase VSI control using interconnection and damping assignment passivity-based control (IDA-PBC) approach has been revisited and analysed on aspects such as voltage gain, output impedance, transient response, stability and steady-state error. It is shown that in the case of accurately known filter parameters and perfectly zero initial conditions, theoretically, the voltage controller would exhibit unity voltage gain and zero output impedance. It is also shown that the IDA-PBC-based voltage controller exhibits a second-order response to a step input. This property has been utilised to propose a novel systematic procedure for tuning of the IDA-PBC gains based on the transient response specifications. The tuning method reveals that the gains for the outer voltage and inner current loops are related to each other and should not be separately tuned. The presented analysis and the proposed tuning method for controller gain have been tested through simulation studies. The concepts were further validated on a laboratory scale prototype of a three-phase VSI for balanced, unbalanced and non-linear loads.

Energy Based Control of a Swash Mass Helicopter Through Decoupling Change of Coordinates

We consider a small helicopter structure that is maneuvered through the control of moving masses. It is referred to as a swash mass helicopter (SMH). This paper addresses the trajectory tracking control problem for the SMH, with a specific focus on the decoupling change of coordinates of both rotational and translational dynamics. We propose a control scheme in which position tracking is the primary objective, while the attitude tracking task is considered as a secondary objective. The intermediate control signals related to the attitude dynamics exploit the structural properties of the SMH and are enhanced with terms that grant a more accurate tracking of the target trajectory. The closed-loop system stability under the trajectory tracking objective is obtained following the Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) approach. In addition, the presence of external disturbances can diminish the trajectory tracking performance. For this reason, a nonlinear outer loop controller is added to the IDA-PBC to compensate the disturbances. Finally, the results of several simulations are reported to evaluate the performance of the control strategy.

Control for EESS in Three-Phase Microgrids Under Time-Domain Reference Frame via PBC Theory

This brief presents a general form of designing passivity-based controllers for electrical energy storage systems (EESS) in three-phase microgrids (TP-MGs) under time-domain reference frame. The control strategy proposed in this brief use the Clark’s transformation known as ${\alpha \beta }$ reference frame, avoiding to use phase-locked loop systems, which allows improving the dynamical performance in the energy storage devices. Passivity-based control guarantees stable operating conditions in the sense of Lyapunov for each EESS for different grid operation scenarios in the TP-MG. The design of the controllers is made by using passivity-based control (PBC) theory in conjunction to the dynamics of the error approach. A comparison to classical proportional-integral control method is used to show the applicability of the PBC approach presented in this brief. Simulation results are conducted via MATLAB/Simulink software.

Standard passivity-based control for multi-hydro-turbine governing systems with surge tank

This paper addresses the problem of control design for hydro-turbine governing systems with surge tanks from the perspective of standard passivity-based control. The dynamic model of a synchronous machine is considered in conjunction with a model of the hydro-turbine to generate an eleventh-order nonlinear set of differential equations. An Euler–Lagrange representati of the system and its open-loop dynamics is developed. Then, the standard passivity-based control is applied to design a global and asymptotically stable controller in closed-loop operation. The proposed control is decentralized to avoid challenges of communication between the hydro-turbine governing systems. The proposed standard passivity-based control approach is compared with two control approaches. First, a classical standard cascade proportional-integral-derivative controller is applied for the governing system, the automatic voltage regulator, and the excitation system. Second, a sliding mode control is also implemented in the governing system. Two test systems were used to validate the performance of the proposed controller. The first test system is a single machine connected to an infinite bus, and the second test system is the well-known Western System Coordinating Council’s multimachine system. Overall, simulation results show that the proposed controller exhibits a better dynamic response with shorter stabilization times and lower peaks during the transient periods.

Robust control approach for handling matched and/or unmatched uncertainties in port‐controlled Hamiltonian systems

This study considers the problem of robust interconnection and damping assignment passivity-based control approach (IDA-PBC) for underactuated mechanical systems from two points of view. First, the robustness of IDA-PBC in the presence of non-vanishing matched and unmatched uncertainties is analysed and sufficient conditions are derived to ensure ultimate boundedness of system. Second, the robust control design is provided by adding a new control input to the former controller designed by IDA-PBC, such that asymptotic stability of the closed-loop system in the face of non-vanishing matched uncertainties is fulfilled. Finally, the proposed robust controller is evaluated through simulations of two practical examples, i.e. an inertia wheel pendulum and a single-link elastic joint robot. The simulation outcomes clearly reveal the effectiveness of the presented robust controller.

Port Controlled Hamiltonian Modeling and IDA-PBC Control of Dual Active Bridge Converters for DC Microgrids

Power electronics-based medium-voltage direct current (MVdc) microgrids consist of several interconnected feedback-controlled switching converters. Such systems experience bus voltage stability challenges owing to the negative incremental resistance of constant power loads and converter control loop interactions. To tackle the stability challenges, this paper presents the application of the interconnection and damping assignment passivity-based control (IDA-PBC) approach to the port-controlled Hamiltonian model of dual active bridge (DAB) source-side converters in an MVdc microgrid. For the DABs, a fundamental average model approach considering phase shift modulation is provided and used for deriving the corresponding IDA-PBC control law. We analyze the effectiveness of the controller on large signal scenarios considering disturbances such as load step up, and DAB disconnection. Hardware-in-the-Loop experiments using Opal-RT and Labview field programmable gate arrays (FPGAs), as well as, low power prototype tests are carried out to demonstrate the validity and feasibility of the proposed approach.