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Control Systems Technology, IEEE Transactions on

Issue 1 • Date Jan. 2014

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Displaying Results 1 - 25 of 45
  • Table of contents

    Publication Year: 2014 , Page(s): C1 - C4
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  • IEEE Transactions on Control Systems Technology publication information

    Publication Year: 2014 , Page(s): C2
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  • Hierarchical Triple-Maglev Dual-Rate Control Over a Profibus-DP Network

    Publication Year: 2014 , Page(s): 1 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1162 KB) |  | HTML iconHTML  

    This paper addresses a networked control system application on an unstable triple-magnetic-levitation setup. A hierarchical dual-rate control using a Profibus-decentralized peripherals network has been used to stabilize a triangular platform composed of three maglevs. The difficulty in control is increased by time-varying network-induced delays. To solve this issue, a local decentralized H∞ control action is complemented by means of a lower rate output feedback controller on the remote side. Experimental results show good stabilization and reference position accuracy under disturbances. View full abstract»

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  • Optimal Operation of Heavy-Haul Trains Equipped With Electronically Controlled Pneumatic Brake Systems Using Model Predictive Control Methodology

    Publication Year: 2014 , Page(s): 13 - 22
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (595 KB) |  | HTML iconHTML  

    An optimal control methodology for heavy-haul trains with the objective to optimize the train's operation in terms of energy consumption, velocity tracking, and operation safety is introduced. Rather than optimize the operation of the train at a specific position, this approach tries to schedule the train during a long period of travel in a model predictive control (MPC) framework; therefore, an effort is made so that the operation strategy of the train is optimal during a track section rather than at a specific position, as is done in existing literature. With this purpose, the cascade mass point model of the train is first simplified and transformed to facilitate the controller design. Then, an optimal controller is presented taking advantage of the MPC concept with the future behavior of the train and all operational constraints considered. Simulations demonstrate the feasibility as well as the advantages of the proposed approach. View full abstract»

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  • Organizational Control of Discrete-Event Systems: A Hierarchical Multiworld Supervisor Design

    Publication Year: 2014 , Page(s): 23 - 33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1210 KB) |  | HTML iconHTML  

    An organizational control architecture for supervising a class of multilevel hierarchical discrete-event systems is proposed in this paper. The architecture can be built on the basis of a standard scalable hierarchical design method, formalizing a common design practice of structuring the control of a discrete-event organization bottom-up into a consistent multiworld control hierarchy. It is shown that, under some mild condition of fairness, a multilevel recursive control law exists that is optimal and nonblocking. This law governs the hierarchy top-down as a dynamic programming recursion, over which an organizational control algorithm is obtained that computes the control decisions partially online and in linear time. It is explained and illustrated how the approach reduces the complexity of off-line control synthesis and increases the online transparency of control operations. View full abstract»

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  • Extremum Seeking-Based Optimization of High Voltage Converter Modulator Rise-Time

    Publication Year: 2014 , Page(s): 34 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6783 KB) |  | HTML iconHTML  

    We digitally implement an extremum seeking (ES) algorithm, which optimizes the rise time of the output voltage of a high voltage converter modulator (HVCM) at the Los Alamos Neutron Science Center by iteratively, simultaneously tuning the first eight switching edges of each of the three-phase drive waveforms (24 variables total). We achieve a 50 μs rise time, which is reduction in half, compared to the 100 μs achieved at the Spallation Neutron Source at Oak Ridge National Laboratory. Considering that HVCMs typically operate with an output voltage of 100 kV, with a 60-Hz repetition rate, the 50 μs rise time reduction will result in very significant energy savings. The ES algorithm will prove successful, despite the noisy measurements and cost calculations, confirming the theoretical results that the algorithm is not affected by noise whose frequency components are independent of the perturbing frequencies. View full abstract»

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  • Driving State Adaptive Control of an Active Vehicle Suspension System

    Publication Year: 2014 , Page(s): 44 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1337 KB) |  | HTML iconHTML  

    A new adaptive vehicle suspension control method is presented that adjusts the controller parametrization to the current driving state and thereby enables to significantly enhance ride comfort while the dynamic wheel load and the suspension deflection remain within safety critical bounds. To this end, the adaptive controller structure dynamically interpolates between differently tuned linear quadratic regulators governed by the dynamic wheel load and the suspension deflection. The stability of the adaptive controller structure is analyzed by means of a common Lyapunov function approach taking into account the nonlinear damper characteristic of the suspension system. In order to provide a realistic framework for the controller design and the performance analysis, a quarter-car test rig based on an all-terrain vehicle suspension that has been equipped with an electrical linear motor to realize an active suspension system, is employed as testbed for the study. On this test rig, the significant performance of the adaptive control concept is successfully validated in a comparison to benchmark suspension controllers. View full abstract»

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  • Dynamic Analysis of the Actively-Controlled Segmented Mirror of the Thirty Meter Telescope

    Publication Year: 2014 , Page(s): 58 - 68
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4847 KB) |  | HTML iconHTML  

    Current and planned large optical telescopes use a segmented primary mirror, with the out-of-plane degrees of freedom of each segment actively controlled. The primary mirror of the Thirty Meter Telescope (TMT) considered here is composed of 492 segments, with 1476 actuators and 2772 sensors. In addition to many more actuators and sensors than at existing telescopes, higher bandwidths are desired to partially compensate for wind-turbulence loads on the segments. Control-structure interaction (CSI) limits the achievable bandwidth of the control system. Robustness can be further limited by uncertainty in the interaction matrix that relates sensor response to segment motion. The control system robustness is analyzed here for the TMT design, but the concepts are applicable to any segmented-mirror design. The key insight is to analyze the structural interaction in a Zernike basis; rapid convergence with additional basis functions is obtained because the dynamic coupling is much stronger at low spatial-frequency than at high. This analysis approach is both computational efficient, and provides guidance for structural optimization to minimize CSI. View full abstract»

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  • Development of a Control-Oriented Model of Floating Wind Turbines

    Publication Year: 2014 , Page(s): 69 - 82
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1926 KB) |  | HTML iconHTML  

    This paper deals with the development of a simplified, control-oriented mathematical model of an offshore variable speed wind turbine with tension leg platform. First, the model is derived with the goal of describing the most relevant physical phenomena of the turbine/platform dynamics, while limiting its complexity. The unknown model parameters are identified and a model validation phase is carried out using Fatigue, Aerodynamics, Structures, and Turbulence (FAST), an accurate reference model available in the literature. Then, an H∞ controller is designed for above-rated power operating conditions. The ability of the controller to attenuate the effect of wind variations and waves is tested in simulation both on the small-scale simulation model and on the FAST simulator. View full abstract»

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  • Optimal Air Path Control During Load Transients on a Spark Ignited Engine With Variable Geometry Turbine and Variable Valve Timing

    Publication Year: 2014 , Page(s): 83 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1430 KB) |  | HTML iconHTML  

    In recent years, the main goal of the automative industry has been to reduce fuel consumption. Downsizing is a promising way to achieve this, which has shown success. Downsized, turbocharged engines suffer from slow transient torque response. This slow response is due to the slow dynamics of the turbocharger. This paper investigates the torque response of a spark ignited engine with variable geometry turbine (VGT) and variable valve timing. Optimal open-loop trajectories for the overlap and the VGT position for a fast transient response are found. This optimization is based on a 1-D simulation model. Based on this optimization, a generic feedback strategy for controlling the VGT is found. This strategy is implemented and evaluated on an engine and shows good performance. View full abstract»

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  • Data-Driven Cooperative Intelligent Controller Based on the Endocrine Regulation Mechanism

    Publication Year: 2014 , Page(s): 94 - 101
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB) |  | HTML iconHTML  

    A data-driven mechanism can achieve effective control by utilizing the online/offline data of the target system, although its performance has not been tuned to a better level. The endocrine regulating mechanism in the human body establishes a rapid responding system to maintain the balance of the body, which can be mathematically derived and therefore provide an inspiration for optimizing the industrial controller. In this paper, a novel data-driven cooperative intelligent controller inspired by the regulating principle of the endocrine system in the human body is proposed. The data-driven component of the proposed controller optimizes the controller parameters by collecting and processing runtime data of the target system. The endocrine regulation-inspired enhancing component tunes the intensity of control signals adaptively. Both the components are further organized by an adaptive distributor so that their behaviors can be regulated dynamically. A dynamic tension control system for acrylic fiber production is taken to verify the performance of the proposed controller. Simulation results show that the proposed controller can realize effective control on systems with unknown or varying models, meanwhile featuring rapid response and effective regulation against external disturbance. View full abstract»

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  • Connecting System Identification and Robust Control for Next-Generation Motion Control of a Wafer Stage

    Publication Year: 2014 , Page(s): 102 - 118
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3504 KB) |  | HTML iconHTML  

    Next-generation precision motion systems are lightweight to meet stringent requirements regarding throughput and accuracy. Such lightweight systems typically exhibit lightly damped flexible dynamics in the controller cross-over region. State-of-the-art modeling and motion control design procedures do not deliver the required model complexity and fidelity to control the flexible dynamical behavior. The aim of this paper is to develop a combined system identification and robust control design procedure for high performance motion control and apply it to a wafer stage. Hereto, new connections between system identification and robust control are employed. The experimental results confirm that the proposed procedure significantly extends existing results and enables next-generation motion control design. View full abstract»

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  • Fuzzy Scheduler Fault-Tolerant Control for Wind Energy Conversion Systems

    Publication Year: 2014 , Page(s): 119 - 131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB) |  | HTML iconHTML  

    In this paper, a new fuzzy scheduler fault-tolerant control method is proposed for nonlinear systems subject to sensor faults, parameter uncertainties, wind disturbance, and state variables unavailable for measurements. An algorithm based on the reconfiguration mechanism is then investigated for detection, isolation, and accommodation of sensor faults. The Takagi-Sugeno fuzzy model is employed to represent the nonlinear wind energy conversion system, and then a model-based fuzzy scheduler controller design uses the concept of general-distributed compensation. Sufficient stability conditions are expressed in terms of linear matrix inequalities, which can be solved very efficiently using convex optimization techniques. The proposed algorithm maximizes the produced power and minimizes the voltage ripple and is able to maintain stability of the system during sensor faults, wind disturbance, and parameter uncertainties. The design procedures are applied to a dynamics model of the typical wind energy conversion system to illustrate the effectiveness of the proposed control technique. View full abstract»

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  • A Generic Instrumental Variable Approach for Industrial Robot Identification

    Publication Year: 2014 , Page(s): 132 - 145
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1367 KB) |  | HTML iconHTML  

    This paper deals with the important topic of industrial robot identification. The usual identification method is based on the inverse dynamic identification model and the least squares technique. This method has been successfully applied on several industrial robots. Good results can be obtained, provided a well tuned derivative band-pass filtering of joint positions is used to calculate the joint velocities and accelerations. However, one cannot be sure whether or not the band-pass filtering is well tuned. An alternative is the instrumental variable (IV) method, which is robust to data filtering and is statistically optimal. In this paper, a generic IV approach suitable for robot identification is proposed. The instrument set is the inverse dynamic model built from simulated data calculated from simulation of the direct dynamic model. The simulation is based on previous estimates and assumes the same reference trajectories and the same control structure for both actual and simulated robots. Finally, gains of the simulated controller are updated according to IV estimates to obtain a valid instrument set at each step of the algorithm. The proposed approach validates the inverse and direct dynamic models simultaneously, is not sensitive to initial conditions, and converges rapidly. Experimental results obtained on a six-degrees-of-freedom industrial robot show the effectiveness of this approach: 60 dynamic parameters are identified in three iterations. View full abstract»

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  • Kernel-Based Approximate Dynamic Programming for Real-Time Online Learning Control: An Experimental Study

    Publication Year: 2014 , Page(s): 146 - 156
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2787 KB) |  | HTML iconHTML  

    In the past decade, there has been considerable research interest in learning control methods based on reinforcement learning (RL) and approximate dynamic programming (ADP). As an important class of function approximation techniques, kernel methods have been recently applied to improve the generalization ability of RL and ADP methods but most previous works were only based on simulation. This paper focuses on experimental studies of real-time online learning control for nonlinear systems using kernel-based ADP methods. Specifically, the kernel-based dual heuristic programming (KDHP) method is applied and tested on real-time control systems. Two kernel-based online learning control schemes are presented for uncertain nonlinear systems by using simulation data and online sampling data, respectively. Learning control experiments were performed on a single-link inverted pendulum system as well as a double-link inverted pendulum system. From the experimental results, it is shown that both online learning control schemes, either using simulation data or using real sampling data, are effective for approximating near-optimal control policies of nonlinear dynamical systems with model uncertainties. In addition, it is demonstrated that KDHP can achieve better performance than conventional DHP, which uses multilayer perceptron neural networks. View full abstract»

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  • Robust Two-Degrees-of-Freedom Attitude Controller Design and Flight Test Result for Engineering Test Satellite-VIII Spacecraft

    Publication Year: 2014 , Page(s): 157 - 168
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2346 KB) |  | HTML iconHTML  

    This paper reports flight test results of robust attitude control for the Engineering Test Satellite VIII (ETS-VIII) spacecraft. The main mission of ETS-VIII is to support next-generation mobile digital communications, and for this purpose it is equipped with two large deployable antenna reflectors and a pair of large solar panels that rotate around the pitch axis. We have proposed and demonstrated several control methods for this spacecraft based on advanced control theories for linear parameter varying multi-input multi-output systems, and in this paper we focus on a two-degrees-of-freedom controller. We describe the controller design methods and present the results of on-orbit flight tests. The controller's superiority is demonstrated by comparing its performance with other controllers. View full abstract»

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  • Modeling and Control of a Renewable Hybrid Energy System With Hydrogen Storage

    Publication Year: 2014 , Page(s): 169 - 179
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1255 KB) |  | HTML iconHTML  

    This paper deals with system integration and controller design for power management of a stand-alone renewable energy (RE) hybrid system, which is at the construction stage in Lambton College (Sarnia, ON, Canada). The system consists of five main components: photovoltaic arrays, wind turbine, electrolyzer, hydrogen storage tanks, and fuel cell. The model for each process component is developed, and all the components are integrated in a Matlab/Simulink environment. A two-level control system is implemented, comprising a supervisory controller, which ensures the power balance between intermittent RE generation, energy storage, and dynamic load demand, as well as local controllers for the photovoltaic, wind, electrolyzer, and fuel cell unit. Simulations are performed to document the efficacy of the proposed power management strategy. View full abstract»

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  • Subnanometer Positioning and Drift Compensation With Tunneling Current

    Publication Year: 2014 , Page(s): 180 - 189
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1545 KB) |  | HTML iconHTML  

    This paper introduces tunneling current as a sensor to detect and control the displacements of micro- and nanoelectromechanical systems. Because of its extremely small magnitude, the tunneling current cannot be used without an appropriate control strategy. A control methodology involving two feedback loops is proposed to control displacements with an accuracy of 40 pm while also compensating the sensor drift. With this strategy, controlling displacements with an amplitude is possible, extending the predicted capabilities of tunneling current by the literature. The overall approach is a solution for the control of macro to nano systems and may be embedded in positioning applications requiring a very high degree of accuracy. View full abstract»

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  • Identification and Vibration Attenuation for the Parallel Robot Par2

    Publication Year: 2014 , Page(s): 190 - 200
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3350 KB) |  | HTML iconHTML  

    Par2 is a parallel robot with two degrees of freedom designed for high-speed and high-accuracy industrial pick-and-place operation tasks. As a result of the high acceleration trajectories, the end-effector undergoes some undesirable vibrations after reaching the stop positions, compromising its precision and leading to an increase in the operation cycle time. Accelerometer sensors placed on the end-effector and piezoelectric patch actuators wrapped around the robot arms are employed in order to actively reduce these vibrations in a noncollocated closed-loop setting. After submitting the robot to an identification procedure, the obtained nominal model is used to synthesize a reduced order controller with the H∞ loop-shaping technique. Performance analysis as well as simulation and experimental results show that vibration reduction is achieved around the nominal operating point, but fails for some extreme operating points, due to high control efforts. An anti-windup strategy is then employed to deal with the saturation of the actuator, which allows achieving vibration attenuation on the whole operation domain, for a given configuration of the robot at the stop point. View full abstract»

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  • Implementation of a Nonlinear Attitude Estimator for Aerial Robotic Vehicles

    Publication Year: 2014 , Page(s): 201 - 213
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1549 KB) |  | HTML iconHTML  

    Attitude estimation is a key component of the avionics suite of any aerial robotic vehicle. This paper details theoretical and practical solutions in order to obtain a robust nonlinear attitude estimator for flying vehicles equipped with low-cost sensors. The attitude estimator is based on a nonlinear explicit complementary filter that has been significantly enhanced with an effective gyro-bias compensation via the design of an anti-windup nonlinear integrator. A measurement decoupling strategy is proposed in order to make roll and pitch estimation robust to magnetic disturbances that are known to cause errors in yaw estimation. In addition, this paper discusses the fixed-point numerical implementation of the algorithm. Finally, simulation and experimental results confirm the performance of the proposed method. View full abstract»

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  • Individual Blade Pitch Control of a Spar-Buoy Floating Wind Turbine

    Publication Year: 2014 , Page(s): 214 - 223
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1276 KB) |  | HTML iconHTML  

    The spar-buoy floating wind turbine is one of the three main floating wind turbine concepts and one of the first to proceed to a full-scale prototype stage. Multiobjective linear state feedback controllers are implemented on the spar-buoy floating wind turbine with individual blade pitching (IBP). The spar-buoy's deep draft results in a low platform pitch and roll natural frequencies. The low-frequency pitch and roll modes interact with other low-frequency modes of the system (i.e., surge and sway, respectively). Therefore, the linear state-space model used for control design must include the surge and sway degrees of freedom. Furthermore, a low platform pitch natural frequency limits the effectiveness of IBP at regulating the platform pitch around the first tower fore-aft (FA) resonant frequency. Simulations using a high-fidelity model are carried out according to design load case 1.2 of the IEC-61400-3 standard for fatigue load testing under normal operating conditions. Simulation results relative to a gain-scheduled proportional-integral controller show that a multiobjective state feedback controller is able to reduce tower FA and side-side bending fatigue loads by an average of 9%. This improvement is mainly due to IBP despite its limited effectiveness around the first tower FA resonant frequency. View full abstract»

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  • Recursive Estimation for Reduced-Order State-Space Models Using Polynomial Chaos Theory Applied to Vehicle Mass Estimation

    Publication Year: 2014 , Page(s): 224 - 229
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (940 KB) |  | HTML iconHTML  

    The main contribution of this paper is to present a recursive estimation/detection technique for reduced-order state-space systems. The recursive state and parameter estimator is built on the framework of polynomial chaos theory and maximum likelihood estimation. The estimator quantifies the reliability of its estimate in real-time by recursively calculating a signal-to-noise ratio. The signal-to-noise ratio (SNR) indicates how well the output of the reduced-order estimation model matches the actual system output. A detection algorithm makes decisions to trust or distrust the current estimate by comparing the current value of the SNR ratio against a threshold value. This paper applies the proposed techniques to estimate the sprung mass of an actual vehicle. It uses a reduced-order model to approximate the complex ride dynamics of the vehicle. Despite the modeling approximations and simplifications, the proposed technique is able to reliably estimate the sprung mass of the vehicle to within 10% of the true value. View full abstract»

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  • Extremum-Seeking Control of ABS Braking in Road Vehicles With Lateral Force Improvement

    Publication Year: 2014 , Page(s): 230 - 237
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (741 KB) |  | HTML iconHTML  

    An ABS control algorithm based on extremum seeking is presented in this brief. The optimum slip ratio between the tire patch and the road is searched online without having to estimate road friction conditions. This is achieved by adapting the extremum-seeking algorithm as a self-optimization routine that seeks the peak point of the tire force-slip curve. As an additional novelty, the proposed algorithm incorporates driver steering input into the optimization procedure to determine the operating region of the tires on the “tire force”-“slip ratio” characteristic-curve. The algorithm operates the tires near the peak point of the force-slip curve during straight line braking. When the driver demands lateral motion in addition to braking, the operating regions of the tires are modified automatically, for improving the lateral stability of the vehicle by increasing the tire lateral forces. A validated, full vehicle model is presented and used in a simulation study to demonstrate the effectiveness of the proposed approach. Simulation results show the benefits of the proposed ABS controller. View full abstract»

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  • Output Regulation of Large-Scale Hydraulic Networks

    Publication Year: 2014 , Page(s): 238 - 245
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (335 KB) |  | HTML iconHTML  

    The problem of output regulation for a class of hydraulic networks found in district heating systems is addressed in this brief. The results show that global asymptotic and semiglobal exponential output regulation is achievable using a set of decentralized proportional-integral controllers. The fact that the result is global and independent of the number of end users has the consequence that structural changes such as end-user addition and removal can be made in the network while maintaining the stability properties of the system. Furthermore, the decentralized nature of the control architecture eases the implementation of structural changes in the network. View full abstract»

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  • Towards Biomimetic Virtual Constraint Control of a Powered Prosthetic Leg

    Publication Year: 2014 , Page(s): 246 - 254
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (458 KB) |  | HTML iconHTML  

    This brief presents a novel control strategy for a powered prosthetic ankle based on a biomimetic virtual constraint. We first derive a kinematic constraint for the “effective shape” of the human ankle-foot complex during locomotion. This shape characterizes ankle motion as a function of the center of pressure (COP)-the point on the foot sole where the resultant ground reaction force is imparted. Since the COP moves monotonically from heel to toe during steady walking, we adopt the COP as a mechanical representation of the gait cycle phase in an autonomous feedback controller. We show that our kinematic constraint can be enforced as a virtual constraint by an output linearizing controller that uses only feedback available to sensors onboard a prosthetic leg. Using simulations of a passive walking model with feet, we show that this novel controller enforces exactly the desired effective shape, whereas a standard impedance (i.e., proportional-derivative) controller cannot. This brief provides a single, biomimetic control law for the entire single-support period during robot-assisted locomotion. View full abstract»

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