Abstract: We present a technique that controls the peak power consumption of a high-density server by implementing a feedback controller that uses precise, system-level power measurement to periodically select the highest performance state while keeping the system within a fixed power constraint. A control theoretic methodology is applied to systematically design this control loop with analytic assurances of system stability and controller performance, despite unpredictable workloads and running environments. In a real server we are able to control power over a 1 second period to within 1 W. Additionally, we have observed that power over an 8 second period can be controlled to within 0.1 W. We believe that we are the first to demonstrate such precise control of power in a real server. Conventional servers respond to power supply constraint situations by using simple open-loop policies to set a safe performance level in order to limit peak power consumption. We show that closed-loop control can provide higher performance under these conditions and test this technique on an IBM BladeCenter HS20 server. Experimental results demonstrate that closed-loop control provides up to 82% higher application performance compared to open-loop control and up to 17% higher performance compared to a widely used ad-hoc technique.

Abstract: This paper proposes a fast-response sliding-mode controller for controlling boost-type converters requiring a fast dynamical response over a wide range of operating conditions. The various aspects of the controller, which include the method of generating the reference-current profile, the choice of sliding surface, the existence and stability properties, and the selection of the control parameters, are discussed. Experimental results are presented to validate the theoretical design and to illustrate the strength of the proposed controller. It is demonstrated that, with the proposed controller, the boost converter has a faster response and a lower voltage overshoot over a wide range of operating conditions as compared to that under the widely used peak current-mode controller. Moreover, it is easily realized with simple analog circuitries.

Abstract: This paper presents the detailed design, analysis, and application of the controller for a shunt active power filter based on a pulsewidth modulation dc-to-ac voltage source converter. The controller is mainly tailored to compensate harmonic currents of nonlinear loads connected to the mains. However, it can also achieve reactive-power compensation and mains-current balancing when required. The controller has a two-layer structure. The outer layer generates the current references for the inner layer. The former uses a plug-in discrete-time repetitive algorithm for current-harmonic compensation, a proportional-integral algorithm to maintain the dc-capacitor voltage in spite of unmodeled losses and a reactive-power-reference generator. The inner layer uses state-feedback with integral action for current control. The repetitive controller is justified to improve the tracking of the periodic current references required by the active filters. The stability of the resulting closed-loop system is studied and some indication of the system robustness is given. The proposed controller has been tested in a prototype with balanced and unbalanced nonlinear loads. A discrete-time model of the filter has been used from the beginning. The microcomputer delay when calculating the controller output and the delay due to the anti-aliasing filters have been included in the inner system state-variable model

Abstract: This paper examines the asymptotic stabilizability of linear systems with delayed input. By explicit construction of stabilizing feedback laws, it is shown that a stabilizable and detectable linear system with an arbitrarily large delay in the input can be asymptotically stabilized by either linear state or output feedback as long as the open-loop system is not exponentially unstable (i.e., all the open-loop poles are on the closed left-half plane). A simple example shows that such results would not be true if the open-loop system is exponentially unstable. It is further shown that such systems, when subject to actuator saturation, are semiglobally asymptotically stabilizable by linear state or output feedback.

Abstract: This paper presents a Direct-Quadrature (DQ) rotating frame control method for single phase full-bridge inverters used in small hybrid power systems. A secondary orthogonal imaginary circuit is created to provide the second phase required for the transformation; thus a DQ model of the inverter is obtained and its controller designed emulating the controls of three-phase power converters. The proposed controller attains infinite loop gain in the rotating coordinate, thus providing zero steady-state error at the fundamental frequency of the converter. The proposed controller is designed and validated through simulations using a DQ-frame average model in Matlab and a detailed switching model in Saber, as well as experimental results obtained with a 2.5 kW single phase full-bridge inverter prototype using a DSP/FPGA based digital control system where the proposed DQ-frame controller is fully implemented.

Abstract: A control system for a minimally invasive surgical system. In one aspect the control system is a distributed system. A control and transform processor receives data from a master arm controller, an instrument controller, an imaging system controller, and a guide tube controller and distributes data received from one controller to the other controllers. The other controllers use the received data, along with received optimization goals, to control associated slave arms in a distributed but coordinated way. In another aspect, the control system is centralized, in which a motion coordinator receives master inputs, sensor inputs from the slave arms, and optimization inputs. The motion coordinator uses the received inputs to output control signals to an instrument, an imaging system, and a guide tube controller.

Abstract: An approach is proposed for vibration suppression in a two-inertia system using an integration of a fractional-order disturbance observer and a single neuron-based PI fuzzy controller. The former is used to obtain disturbance estimate and generate compensation signal, and the latter is utilized to realize outer loop control. Fractional-order disturbance observer has a wider range to select a suitable tradeoff between robustness and vibration suppression, because introduction of fractional calculus makes universe of relative degree of Q-filter is expanded from integer domain to real-number domain. For the single neuron-based PI fuzzy controller, a single neuron makes up a PI controller and such a controller is embedded in each cell of the fuzzy control table. Thus, the fuzzy control table is changed into a controller matrix and it constructs a nonlinear adaptive controller with parameter self-tuning property. Experimental results illustrate that the integration of fractional-order disturbance observer and single neuron-based PI fuzzy controller can improve the performance of disturbance attenuation and system robustness

Abstract: We examine in this paper the complex problem of simultaneous position and internal force control in multiple cooperative manipulator systems. This is done in the presence of unwanted parametric and modeling uncertainties as well as external disturbances. A decentralized adaptive hybrid intelligent control scheme is proposed here. The controller makes use of a multi-input multi-output fuzzy logic engine and a systematic online adaptation mechanism. Unlike conventional adaptive controllers, the proposed controller does not require a precise dynamical model of the system's dynamics. As a matter of fact, the controller can achieve its control objectives starting from partial or no a priori knowledge of the system's dynamics. The ability to incorporate the already acquired knowledge about the system's dynamics is among what distinguishes the proposed controller from its predecessor adaptive fuzzy controllers. Using a Lyapunov stability approach, the controller is proven to be robust in the face of varying intensity levels of the aforementioned uncertainties. The position and the internal force errors are also shown to asymptotically converge to zero under such conditions

Abstract: In this paper, we study fundamental limitations of disturbance attenuation of feedback systems, under the assumption that the controller has a finite horizon preview of the disturbance. In contrast with prior work, we extend Bode's integral equation for the case where the preview is made available to the controller via a general, finite capacity, communication system. Under asymptotic stationarity assumptions, our results show that the new fundamental limitation differs from Bode's only by a constant, which quantifies the information rate through the communication system. In the absence of asymptotic stationarity, we derive a universal lower bound which uses Shannon's entropy rate as a measure of performance. By means of a case-study, we show that our main bounds may be achieved

Abstract: The field-oriented control of induction machines is widely used in high-performance applications. However, detuning caused by parameter disturbances still limits the performance of these drives. In order to accomplish variable-speed operation, conventional PID-like controllers are commonly used. These controllers provide limited good performance over a wide range of operation, even under ideal field-oriented conditions. An alternate approach is to use the so-called ldquofuzzyrdquo controller. In this paper, a self-tuning fuzzy controller is implemented. The proposed controller has the ability to adjust its parameters online according to the error between actual machine speed and a model reference. The scheme is compared to the conventional proportional-integral control and validated by simulation and experimental tests of both control techniques.

Abstract: A fuzzy-neural sliding-mode (FNSM) control system is developed to control power electronic converters. The FNSM control system comprises a neural controller and a compensation controller. In the neural controller, an asymmetric fuzzy neural network is utilized to mimic an ideal controller. The compensation controller is designed to compensate for the approximation error between the neural controller and the ideal controller. An online training methodology is developed in the Lyapunov sense; thus, the stability of the control system can be guaranteed. Finally, to investigate the effectiveness of the FNSM control scheme, it is applied to control a pulsewidth-modulation-based forward dc-dc converter. Experimental results show that the proposed FNSM control system is found to achieve favorable regulation performances even under input-voltage and load-resistance variations

Abstract: A controller equipped with a controller interface configured to accept one or more input parameters is disclosed, including methods for programming such devices. An illustrative controller interface may include a number of knobs, slides, buttons, or other input means for setting various set-points within the controller that can be used to control one or more HVAC system components of a building or structure. The input parameters may correspond directly to physical parameters of the building or structure being regulated, allowing the user to program the controller without having an extensive knowledge of HVAC systems or their operation.

Abstract: This paper presents a novel adaptive control methodology for uncertain systems with time-varying unknown parameters and time-varying bounded disturbances. The adaptive controller ensures uniformly bounded transient and asymptotic tracking for system's both signals, input and output, simultaneously. The performance bounds can be systematically improved by increasing the adaptation rate. Simulations of a robotic arm with time-varying friction verify the theoretical findings.

Abstract: Open-loop transfer functions can be used to create closed-loop models of pulsewidth-modulated (PWM) converters. The closed-loop small-signal model can be used to design a controller for the switching converter with well-known linear control theory. The dynamics of the power stage for boost PWM dc-dc converter operating in continuous-conduction mode (CCM) are studied. The transfer functions from output current to output voltage, from duty cycle to output voltage including MOSFET delay, and from input voltage to output voltage are derived. The derivations are performed using an averaged linear circuit small-signal model of the boost converter for CCM. Experimental Bode plots and step responses were used to test the accuracy of the derived transfer functions. The theoretical and experimental responses were in excellent agreement, confirming the validity of the derived transfer functions

Abstract: A system for controlling a motor for use in a ventilation system may include a motor, a voltage adjustment system, a user interface, and a motor controller. The voltage adjustment system may be configured to adjust a voltage applied to the motor. The user interface may be configured to receive patient settings input from a user and communicate target ventilation parameters to the motor controller. The motor controller may include a calculation engine configured to calculate motor performance parameters for achieving the target ventilation parameters, and based at least on the calculated motor performance parameters, perform a voltage adjustment analysis for controlling the voltage adjustment system. The motor controller may further include a voltage adjuster controller configured to activate the voltage adjustment system based on a first result of the voltage adjustment analysis and to not activate the voltage adjustment system based on a second result of the voltage adjustment analysis.

Abstract: A decentralized model reference adaptive controller (MRAC) for a class of large-scale systems with unmatched interconnections is developed in this paper. A novel reference model is proposed for the class of large-scale systems considered and a decentralized, full-state feedback adaptive controller is developed for each subsystem of the large-scale system. It is shown that with the proposed decentralized adaptive controller, the states of the subsystems can asymptotically track the desired reference trajectories. To substantiate the performance of the proposed controller, a large web processing line, which mimics most of the features of an industrial web process line, is considered for experimental study. Extensive experiments were conducted with the proposed decentralized adaptive controller and an often used decentralized industrial proportional-integral (PI) controller. A representative sample of the comparative experimental results is shown and discussed

Abstract: A controller for a power processing circuit and a related method of operating the same. In one embodiment, the controller includes a multiplier configured to produce a product of an input current and an input voltage of the power processing circuit. The controller also includes a low-pass filter configured to produce an input power estimate of an input power to the power processing circuit as a function of the product of the input current and the input voltage. In another embodiment, the controller is a power-factor controller and includes a voltage loop compensator configured to produce a voltage compensation signal as a function of an output voltage of the power processing circuit. The controller also includes an input power estimator configured to produce an input power estimate of an input power to the power processing circuit as a function of the voltage compensation signal.

Abstract: A controller design methodology is given for a quadratic boost converter with a single switch using current-programmed control. Nonlinear and linear models are developed, the later exhibits fourth-order characteristic dynamics with complex right-half plane zeros. The proposed control scheme is based on sensing the current of the switch and using it for feedback purposes. When the current loop is introduced, the fourth-order dynamics of the converter are changed to a dominant first order, which simplifies substantially the controller design of the outer loop. For this loop, a conventional controller is designed. The design-oriented analytic results allow the designer to easily pinpoint the control circuit parameters that optimise the converter's performance. At the end, experimental results are given for a 23 W quadratic boost converter where open loop and closed-loop response are compared.

Abstract: Speed Control.- Basic Structure of the Speed Controller.- Parameter Setting of Analog Speed Controllers.- Digital Speed Control.- Digital Position Control.- The Position Controller with Integral Action.- Trajectory Generation and Tracking.- Torsional Oscillations and the Antiresonant Controller.

Abstract: The object of the present invention is to provide an electric power steering controller in which a redundant system equal to that with a relay is configured, without incurring the upsizing or deterioration in reliability, of the controller. An electric power steering controller involving the present invention is provided with a motor for providing a steering system with output torque; a motor driving circuit for driving the motor; a microcontroller for calculating a current to be applied to the motor; a gate driver for driving a plurality of switching devices constituting a bridge circuit, based on the result of the calculation by the microcontroller; and a switching portion for cutting off the power supply to the gate driver.

Abstract: A new approach to the automatic control of excitation parameters for the switched-reluctance motor (SRM) is presented. The excitation parameters include the turn-on angle, the turn-off angle and the magnitude of the phase current. The objective is to develop an easily implementable control algorithm that automatically maintains the most efficient excitation angles in producing the required current to produce the electromagnetic torque. The control algorithm determining the turn-on and turn-off angles supports the most efficient operation of the motor drive system. The turn-on angle and turn-off angle controllers work independently and harmoniously with the speed controller. The turn-on angle controller consists of two pieces: the first piece of the control technique monitors the position of the first peak of the phase current (thetas p ) and seeks to align this position with the angle where the inductance begins to increase (thetas m ). The second piece of the controller monitors the peak phase current and advances the turn-on angle if the commanded reference current cannot be produced by the controller. The first piece of the controller tends to be active below base speed of the SRM, where phase currents can be built easily by the inverter and thetas p is relatively independent of thetas m . The second piece of the controller is active above base speed, where the peak of the phase currents tends to naturally occur at thetas m regardless of the current amplitude. The two pieces of the controller naturally exchange responsibility as a result of a change in command or operating point. The turn-off angle controller works independent of the turn-on angle controller. Through modelling of an experimental SRM and extensive simulation, it is seen that the optimal-efficiency turn-off angles can be characterised as a function of peak phase current and motor speed. Accordingly, the optimal-efficiency turn-off angle is determined from an analytic curve fit. It has been shown that a curve fit using only four optimised points gives very close estimation to the most efficient turn-off angle at any given operating point. The SRM, inverter and control system are modelled in Simulink to demonstrate the operation of the system. The modelling is based on the finite element data that include spatial nonlinearities and magnetic saturation. The control technique is then applied to an experimental SRM system. Experimental operation documents that the technique provides for efficient operation of the SRM system through tuning the controller at only four operating points

Abstract: In this paper, an adaptive neural network sliding-mode controller design approach with decoupled method is proposed. The decoupled method provides a simple way to achieve asymptotic stability for a class of fourth-order nonlinear system. The adaptive neural sliding-mode control system is comprised of neural network (NN) and a compensation controller. The NN is the main regulator controller, which is used to approximate an ideal computational controller. The compensation controller is designed to compensate for the difference between the ideal computational controller and the neural controller. An adaptive methodology is derived to update weight parts of the NN. Using this approach, the response of system will converge faster than that of previous reports. The simulation results for the cart-pole systems and the ball-beam system are presented to demonstrate the effectiveness and robustness of the method. In addition, the experimental results for seesaw system are given to assure the robustness and stability of system.

Abstract: Robots are expected to expand their range of activities to human environment. Robots in human environment need redundancy for environmental adaptation. Furthermore, they have to automatically modify their controllers in response to varying conditions of the environment. Therefore, the authors have proposed a method to design a hyper-degrees-of-freedom (DOF) control system efficiently. The method decouples a large control system into small independent components called ldquofunction.rdquo Motion of the entire control system is expressed as superposition of multiple functions. Combination of some functions realizes many patterns of motion. Hence, various motions are realized with much smaller efforts on controller design. Additionally, the controller design is explicit since a controller and a function correspond directly. This paper expands the method to multi-DOF robots in 3-D space, since the conventional method was limited to a multirobot system in 1-D space. A new problem of interference among function-based systems occurs along with the expansion. A disturbance observer is applied on each actuator to eliminate the interference. Procedures of controller design under varying conditions are also shown. The proposed method is applied to a grasping manipulator with 18 DOF. Its experimental results show the validity of the method.

Abstract: A simulation and control system for a machine is disclosed. The simulation and control system may have a user interface configured to display a simulated environment. The machine simulation and control system may also have a controller in communication with the user interface and a remotely located machine. The controller may be configured to receive from the machine real-time information related to operation of the machine at a worksite. The controller may also be configured to simulate the worksite, operation of the machine, and movement of a machine tool based on the received information. The controller may further be configured to provide to the user interface the simulated worksite, operation, and movement in the simulated environment.

Abstract: The concept of unfalsified adaptive control using multiple controllers and switching ideas has been developed and extensively investigated over the past decade [1]–[16] In this literature of unfalsified adaptive control, it is required that the controller set only contains linear, bi-proper minimum-phase controllers In this note, we propose a controller implementation scheme which overcomes this restrictive assumption on the controller set though retaining linearity Furthermore, we advocate caution in some circumstances where the unfalsified adaptive control algorithm actually connects up a destabilizing controller in the closed-loop for a long period of time, and explain how this phenomenon can arise