Showing papers on "Proportional control published in 2010"

A New Feedback Method for PR Current Control of LCL-Filter-Based Grid-Connected Inverter

Abstract: For a grid-connected converter with an LCL filter, the harmonic compensators of a proportional-resonant (PR) controller are usually limited to several low-order current harmonics due to system instability when the compensated frequency is out of the bandwidth of the system control loop. In this paper, a new current feedback method for PR current control is proposed. The weighted average value of the currents flowing through the two inductors of the LCL filter is used as the feedback to the current PR regulator. Consequently, the control system with the LCL filter is degraded from a third-order function to a first-order one. A large proportional control-loop gain can be chosen to obtain a wide control-loop bandwidth, and the system can be optimized easily for minimum current harmonic distortions, as well as system stability. The inverter system with the proposed controller is investigated and compared with those using traditional control methods. Experimental results on a 5-kW fuel-cell inverter are provided, and the new current control strategy has been verified.

A Fractional Order Proportional and Derivative (FOPD) Motion Controller: Tuning Rule and Experiments

Abstract: In recent years, it is remarkable to see the increasing number of studies related to the theory and application of fractional order controller (FOC), specially PI ? D ? controller, in many areas of science and engineering. Research activities are focused on developing new analysis and design methods for fractional order controllers as an extension of classical control theory. In this paper, a new tuning method for fractional order proportional and derivative (PD ?) or FO-PD controller is proposed for a class of typical second-order plants. The tuned FO-PD controller can ensure that the given gain crossover frequency and phase margin are fulfilled, and furthermore, the phase derivative w. r. t. the frequency is zero, i.e., the phase Bode plot is flat at the given gain crossover frequency. Consequently, the closed-loop system is robust to gain variations. The FOC design method proposed in the paper is practical and simple to apply. Simulation and experimental results show that the closed-loop system can achieve favorable dynamic performance and robustness.

Decentralized Parallel Operation of Inverters Sharing Unbalanced and Nonlinear Loads

Abstract: In this paper, a wireless control strategy for parallel operation of three-phase four-wire inverters is proposed. A generalized situation is considered where the inverters are of unequal power ratings and the loads are nonlinear and unbalanced in nature. The proposed control algorithm exploits the potential of sinusoidal domain proportional+multiresonant controller (in the inner voltage regulation loop) to make the system suitable for nonlinear and unbalanced loads with a simple and generalized structure of virtual output-impedance loop. The decentralized operation is achieved by using three-phase P/Q droop characteristics. The overall control algorithm helps to limit the harmonic contents and the degree of unbalance in the output-voltage waveform and to achieve excellent power-sharing accuracy in spite of mismatch in the inverter output impedances. Moreover, a synchronized turn on with consequent change over to the droop mode is applied for the new incoming unit in order to limit the circulating current completely. The simulation and experimental results from -1 kVA and -0.5 kVA paralleled units validate the effectiveness of the scheme.

Proxy-Based Sliding Mode Control: A Safer Extension of PID Position Control

Abstract: High-gain proportional-integral-derivative (PID) position control involves some risk of unsafe behaviors in cases of abnormal events, such as unexpected environment contacts and temporary power failures. This paper proposes a new position-control method that is as accurate as conventional PID control during normal operation, but is capable of slow, overdamped resuming motion without overshoots from large positional errors that result in actuator-force saturation. The proposed method, which we call proxy-based sliding mode control (PSMC), is an alternative approximation of a simplest type of sliding mode control (SMC), and also is an extension of the PID control. The validity of the proposed method is demonstrated through stability analysis and experimental results.

Single-Loop Digital Control of High-Power 400-Hz Ground Power Unit for Airplanes

Abstract: In this paper, the influence of one-sample delay for sampling and computation in digital control on the bandwidth of the inner current loop of a 400-Hz ground power unit (GPU) is analyzed first. The results show that it is difficult and even impossible for high-power 400-Hz GPUs to maintain low total harmonic distortion content in the output voltage with the conventional proportional-integral-based double-loop control. To improve the performance, resonant controllers with parallel structure which are widely used in active power filters are applied to the single-loop control of the 400-Hz GPU. The parameter design criterion for the parallel resonant controllers is discussed in the discrete time domain. Meanwhile, adoption of proportional gain in the single-loop control is investigated. The results show that it can improve the performance little and may cause instability problems. Comparisons between different control methods for the 400-Hz GPU are also made, and the single-loop control method in this paper seems to be the most suitable one in terms of simplicity and performance. Experiments on a 16-b fixed-point DSP-controlled 90-kVA 400-Hz GPU prototype show satisfactory results of the single-loop method feeding linear/nonlinear and balanced/unbalanced loads.

Optimization of Delayed-State Kalman-Filter-Based Algorithm via Differential Evolution for Sensorless Control of Induction Motors

Abstract: This paper proposes the employment of the differential evolution (DE) to offline optimize the covariance matrices of a new reduced delayed-state Kalman-filter (DSKF)-based algorithm which estimates the stator-flux linkage components, in the stationary reference frame, to realize sensorless control of induction motors (IMs). The DSKF-based algorithm uses the derivatives of the stator-flux components as mathematical model and the stator-voltage equations as observation model so that only a vector of four variables has to be offline optimized. Numerical results, carried out using a low-speed training test, show that the proposed DE-based approach is very promising and clearly outperforms a classical local search and three popular metaheuristics in terms of quality of the final solution for the problem considered in this paper. A novel simple stator-flux-oriented sliding mode (SFO-SM) control scheme is online used in conjunction with the optimized DSKF-based algorithm to improve the robustness of the sensorless IM drive at low speed. The SFO-SM control scheme has closed loops of torque and stator-flux linkage without proportional-plus-integral controllers so that a minimum number of gains has to be tuned.

A Proportional-Resonant Controller-Based Wireless Control Strategy With a Reduced Number of Sensors for Parallel-Operated UPSs

Abstract: In this paper, a novel droop method to control the power sharing of parallel uninterruptible-power-supply (UPS) systems is presented. In a clear-cut contrast to the previously reported works, the controller is a proportional-resonant controller which ensures good transient response and steady-state objectives. Furthermore, the need for sensing the output current for the power-sharing control is removed by implementing it in a software routine. This brings a less complicated and less expensive structure in which the number of feedback sensors is reduced from three to two. The droop paralleling strategy is based on the drop in the inverter output frequency and amplitude. The application of proportional-resonant controllers based on internal model principle is also extended to parallel inverters, and its superior performance over the well-known proportional-integral-derivative controller is presented. In order to show the performance of the proposed system, two parallel-connected UPS systems are analyzed, and two types of linear and nonlinear loads are considered. The nonlinear load is compliant with IEC 62040-3 standard for class I UPS. The results show that the reduction of sensors does not result in any error, and the performance of the control system is excellent. To verify the proposed concept, the proposed strategy is implemented within two-625VA UPS systems. Several test results are provided for linear and nonlinear loads which validate the simulations results. The results indicate that the proposed parallel inverter structure offers a better system in terms of the number of feedback sensors, performance, and complication.

New Stationary Frame Control Scheme for Three-Phase PWM Rectifiers Under Unbalanced Voltage Dips Conditions

Abstract: A new stationary frame control scheme for three-phase pulsewidth-modulation (PWM) rectifiers operating under unbalanced voltage dips conditions is proposed in this paper The proposed control scheme regulates the instantaneous active power at the converter poles to minimize the harmonics of the input currents and the output voltage ripple This paper's novelty is the development of a new current-reference generator implemented directly in stationary reference frame This allows using proportional sinusoidal signal integrator (P-SSI) controllers for simultaneous compensation of both positive and negative current sequence components No phase-locked loop (PLL) strategies and coordinate transformations are needed for the proposed current-reference generator Experimental results are presented for a 20-kV A alternative current (ac)/direct current (dc) converter prototype to demonstrate the effectiveness of the proposed control scheme A comparison with two other existing control techniques is also performed Fast dynamic performance with small dc-link voltage ripple and input sinusoidal currents are obtained with this control scheme, even under severe voltage dips operating conditions

Output Power Control for Variable-Speed Variable-Pitch Wind Generation Systems

Abstract: A robust pitch control strategy for the output power control of wind generator systems in wide-wind-speed range is presented in this paper. The corresponding controller is designed, which consists of a nominal inverse-system controller and a robust compensator. The advantages of the proposed strategy include the simple implementation, tolerance of turbine parameter or some nonparametric uncertainties, and robust control of the generator output power with wind-speed variations. Theoretical analyses, simulation, and experimental results show that the proposed controller can work better in a wide-wind-speed range compared with the traditional proportional-integral-derivative controller. It has similar performance with the neural network controller, but less complexity. Additionally, it can be easily adapted to other wind generator systems.

H ∞ repetitive voltage control of gridconnected inverters with a frequency adaptive mechanism

Abstract: A voltage controller is proposed and implemented for grid-connected inverters based on H∞ and repetitive control techniques A frequency adaptive mechanism is introduced to improve system performance and to cope with grid frequency variations The repetitive control, based on the internal model principle, offers excellent performance for voltage tracking, as it can deal with a very large number of harmonics simultaneously This leads to a very low total harmonic distortion and improved tracking performance It turns out that the controller can be reduced to a proportional gain cascaded with the internal model (in a re-arranged form), which can be easily implemented in real applications The proposed controller is experimentally tested to validate its performance, focusing on reducing tracking error and total harmonic distortion, under different scenarios (eg in the stand-alone mode or in the grid-connected mode, with or without the frequency adaptive mechanism, with linear or non-linear loads etc)

System properties, feedback control and effector coordination of human temperature regulation.

Abstract: The aim of human temperature regulation is to protect body processes by establishing a relative constancy of deep body temperature (regulated variable), in spite of external and internal influences on it. This is basically achieved by a distributed multi-sensor, multi-processor, multi-effector proportional feedback control system. The paper explains why proportional control implies inherent deviations of the regulated variable from the value in the thermoneutral zone. The concept of feedback of the thermal state of the body, conveniently represented by a high-weighted core temperature (T (c)) and low-weighted peripheral temperatures (T (s)) is equivalent to the control concept of "auxiliary feedback control", using a main (regulated) variable (T (c)), supported by an auxiliary variable (T (s)). This concept implies neither regulation of T (s) nor feedforward control. Steady-states result in the closed control-loop, when the open-loop properties of the (heat transfer) process are compatible with those of the thermoregulatory processors. They are called operating points or balance points and are achieved due to the inherent property of dynamical stability of the thermoregulatory feedback loop. No set-point and no comparison of signals (e.g. actual-set value) are necessary. Metabolic heat production and sweat production, though receiving the same information about the thermal state of the body, are independent effectors with different thresholds and gains. Coordination between one of these effectors and the vasomotor effector is achieved by the fact that changes in the (heat transfer) process evoked by vasomotor control are taken into account by the metabolic/sweat processor.

Gain-Scheduling Regulator for High-Performance Position Control of Switched Reluctance Motor Drives

Abstract: The problem of high-precision position control in switched reluctance motor (SRM) drives is investigated in this paper. Advanced proportional-integral and proportional-differential controllers for speed and position controls, respectively, are adopted. A gain-scheduling technique is adopted in the speed controller design for providing high dynamic performance and precise position control. In order to improve the set-point tracking, a low-pass filter is included in the position controller. The proposed four-quadrant control scheme is based on the average torque control method. The turn-on and turn-off angles are online determined through simple formulas so as to reduce the torque ripple at an acceptable level over a wide speed range. This is important since the position precision is highly influenced from the motor torque ripple. Experimental results of the SRM dynamic response are presented to verify the theoretical considerations and to demonstrate the effectiveness of the proposed control scheme.

Transient Control of Electro-Hydraulic Fully Flexible Engine Valve Actuation System

Abstract: Fully flexible valve actuation (FFVA) system, often referred to as camless valvetrain, employs electronically controlled actuators in place of the camshaft to drive the intake and/or exhaust valves for internal combustion engines. This system enables the engine controller to tailor the valve event according to the engine operating condition in real-time to improve fuel economy, emissions, and torque output performance. This paper presents the transient control of a laboratory electro-hydraulic fully flexible valve actuation system. Transient control of the FFVA system includes lift transient, duration transient, phase transient, speed transient, and mode transient. With constant engine speed, the valve profile is periodic in time domain and the lift, phase, and duration transients can be realized using robust repetitive control. When the engine speed varies, the period of the valve profile changes in real-time. This phenomenon poses a fundamental challenge to the transient control problem and repetitive control cannot be applied anymore. To overcome this challenge, we propose a new valve profile consisting of a periodic portion and a dwell portion with time-varying duration. Robust repetitive control is then applied to the periodic portion and proportional plus integral and derivative (PID) control is applied to the dwell portion. These two controls are switched in real-time to achieve asymptotic valve profile tracking performance. To demonstrate the effectiveness of the proposed control method, we show real-time valve-lift profiles used to explore homogeneous charge compression ignition (HCCI) combustion at different engine operating conditions.

A Novel Neuro-Wavelet-Based Self-Tuned Wavelet Controller for IPM Motor Drives

Abstract: This paper presents a hybrid neuro-wavelet scheme for online tuning of a wavelet-based multiresolution proportional integral derivative (MRPID) controller in real time for precise speed control of an interior permanent-magnet synchronous motor (IPMSM) drive system under system uncertainties. In the proposed wavelet-based MRPID controller, the discrete wavelet transform (DWT) is used to decompose the speed error between actual and command speeds into different frequency components at various scales of the DWT. The MRPID controller parameters are tuned online by the wavelet neural network (WNN) to ensure optimal performance of the drive system. The neurowavelet-based MRPID controller is trained online with adaptive learning rates in the closed-loop control of the IPMSM drive system. The adaptive learning rates are derived using the discrete Lyapunov stability theorem so that the convergence of speed tracking error could be guaranteed in the closed-loop system. The performance of the proposed hybrid controller is investigated in both simulation and experiments at different dynamic operating conditions. The complete vector control scheme incorporating the proposed self-tuning MRPID controller is successfully implemented in real time using the digital signal processor board ds1102 for the laboratory 1-hp interior permanent-magnet motor. The superior performance of the proposed WNN-based self-tuning MRPID controller is also validated over fixed-gain controllers.

Self-Tuning of the PID Controller for a Digital Excitation Control System

Abstract: This paper proposes an indirect method for self-tuning of the proportional, integral, and derivative (PID) controller gains. Some of the modern voltage regulator systems are utilizing PID control for stabilization. Based on given excitation system parameters, several PID tuning approaches are reported. Since in general, these parameters are not available during commissioning, specifically the machine time constants, this lack of information causes a considerable time delay and cost of fuel usage for commissioning the automatic voltage regulator (AVR). To reduce the commissioning time and cost, the excitation system parameters are automatically identified and the PID gains are calculated using well-developed algorithms. Recursive least-square (RLS) with linearization via feedback is proposed to identify the system parameters. The performance of the proposed method is evaluated with several generator sets. With self-tuned PID gains, commissioning is accomplished very quickly with excellent performance results.

Smart optimal control of DC-DC boost converter in PV systems

Abstract: Proportional integral derivative (PID) controllers are usually used to control DC-DC boost converters in PV systems. However, they have to be tuned based on certain defined operating range using averaged mathematical models. Loading conditions have great effect on PI controllers; PI controllers are subjected to failure under dramatic load changes. This limits the PI controller's operating range. Moreover, transient and steady state response both get affected by changing the operating range. This paper presents a novel smart-PID controller for optimal control of DC-DC boost converter used as voltage controller in PV systems. This proposed controller maximizes the stable operating range by using genetic algorithms (GA) to tune the PID parameters ultimately at various loading conditions. Then, a fuzzy logic approach is used to add a factor of intelligence to the controller such that it can move among different values of proportional gain (Kp), derivative gain (Kd) and integral gain (Ki) based on the system conditions. This controller allows optimal control of boost converter at any loading condition with no need to retune parameters or possibility of failure. Moreover, the paper presents a novel technique to move between the PI and PID configurations of the controller such that the minimum overshoot and ripple are obtained, which makes the controller very applicable for PV systems supplying sensitive loads. The controlled boost converter is used as an interface between photovoltaic (PV) panels and the loads connected to them. It converts any input voltage within its operating range into a constant output voltage that is suitable for load feeding. The proposed smart controller adapts the duty cycle of the boost converter based on input voltage and loading conditions such that it outputs a constant output voltage. A prototype system has been developed to verify the applicability of the proposed controller. Moreover, simulation and experimental results both confirm its validity as an effective and reliable controller for boost converters in PV systems and the possibility to use it in different applications.

Depth control of an autonomous underwater vehicle, STARFISH

Abstract: We present a depth controller design for a torpedo-shaped autonomous underwater vehicle (AUV) known as STARFISH. It is common to design an AUV to be positively buoyant, so that it will float to the surface in case of power failure. However, most depth controllers are designed with a neutral buoyancy assumption by regarding the extra buoyancy as a disturbance. In this paper, we study the effect of buoyancy on both pitch and heave dynamics of an AUV, and propose a controller scheme that specifically compensates for the effect. We propose a simplified model for pitch dynamics that takes into account the buoyancy of the AUV. We identify the parameters of the model from field data from a closed loop depth maneuver. We adopt dual loop control methodology with inner pitch control loop and outer depth control loop. The inner pitch controller is designed using sliding mode control (SMC) with integrator effect to overcome a constant offset term due to positive buoyancy of the AUV. Then, a simple proportional controller is designed in the outer loop for depth control. Positive buoyancy of the vehicle will induce heave motion of the AUV. Thus, in order to maintain depth, the AUV need to be pitch down at certain angle. An adaptive feedforward controller is designed to compensate for this angle. The dual loop design with inner SMC and outer proportional control with feedforward loop was shown to be effective through experiments in both lake and sea.

On-Line Supervisory Control Design for Maglev Transportation System via Total Sliding-Mode Approach and Particle Swarm Optimization

Abstract: This study focuses on the design of an on-line levitation and propulsion control for a magnetic-levitation (maglev) transportation system. First, the dynamic model of a maglev transportation system including levitated electromagnets driven by linear servo amplifiers and a propulsive linear induction motor (LIM) based on the concepts of mechanical geometry and motion dynamics is developed. Then, a total sliding-mode (TS) control strategy is introduced, and the concept of TS control is incorporated into particle swarm optimization (PSO) to form an on-line TSPSO control framework with varied inertial weights for preserving the robust control characteristics and reducing the chattering control phenomena of TS control. In this TSPSO control scheme, a PSO control system is utilized to be the major controller, and the stability can be indirectly ensured by the concept of TS control without strict constraint and detailed system knowledge. In order to further directly stabilize the system states around a predefined bound region and effectively accelerate the searching speed of the PSO control, a supervisory mechanism is embedded into the TSPSO control to constitute a supervisory TSPSO (STSPSO) control strategy. The effectiveness of the proposed control schemes for the maglev transportation system is verified by numerical simulations and experimental results, and the superiority of the STSPSO control scheme is indicated in comparison with the adaptive fuzzy neural network, PSO-based proportional-integral-differential, TS and TSPSO control strategies.

Optimal System Design of SISO-Servopneumatic Positioning Drives

Abstract: Servopneumatic actuators are very attractive for automated handling tasks or robot operations. They have many advantages such as high speed, high robustness in rough manufacturing environment or high power-to-weight ratio. The considered actuator system is a standard configuration in pneumatics consisting of a double acting pneumatic cylinder controlled by a proportional directional control valve. For the set-up a detailed mathematical model is derived. In order to guarantee an accurate tracking behaviour, a model-based nonlinear controller is presented. Model based approaches for the control design have several advantages. Tuning of the controller can be reached in a systematic way even in the case of a large variety of different configurations. But not only the control design itself can be treated. The model offers the possibility to optimize the size of components for demanded automation tasks. In most cases, this is solved based on steady state assumptions. In this contribution, a method for a design procedure for the pneumatic actuator system based on the dynamic equation is presented. With the representation of the system, an optimization procedure for the components is introduced. The optimization criteria consist of the minimization of the air consumption and investment costs.

Repetitive controller for time-delay systems based on disturbance observer

Abstract: A novel continuous time repetitive control design is presented for time-delay systems with periodic references and disturbances. Taking profit of the system model and an appropriate time-delay, an inner positive feedback loop is constructed to establish an internal model for periodic signals, and a simple proportional control is utilised in the outer feedback loop to stabilise the closed-loop system. Thus, the tracking capability can be guaranteed according to internal model principle. In addition, to compensate for the effect of external periodic disturbances, a disturbance observer using the system model and a model-based compensator is introduced inside the proposed internal model such that the tracking and disturbance rejection can be achieved simultaneously. Sufficient stability conditions and the robustness analysis under modelling uncertainties are all studied. Only two parameters are needed to be chosen by the designer. Numerical examples and practical experiments on a motor control system are included to illustrate the feasibility and simplicity of the proposed methods.

PD Fuzzy Logic with non-collocated PID approach for vibration control of flexible joint manipulator

Abstract: The increased complexity of the dynamics of robots manipulator considering joint elasticity makes conventional model-based control strategies complex and difficult to synthesize. This paper presents investigations into the development of PD type Fuzzy Logic Control (FLC) with non-collocated Proportional Integral Derivative (PID) for trajectory tracking and vibration control of a flexible joint manipulator. To study the effectiveness of the controllers, a PD type Fuzzy Logic Controller is developed for tip angular position control of a flexible joint manipulator. This is then extended to incorporate a non-collocated PID Controller for vibration reduction of the flexible joint system. Simulation results of the response of the flexible joint manipulator with the controllers are presented in time and frequency domains. The performances of the non-collocated PID control schemes are examined in terms of input tracking capability, level of vibration reduction and time response specifications. Finally, a comparative assessment of the control techniques is presented and discussed.

A path following algorithm for mobile robots

Abstract: This paper considers path following control for a robotic platform. The vehicle used for the experiments is a specially designed robotic platform for performing autonomous weed control. The platform is four-wheel steered and four-wheel driven. A diesel engine powers the wheels via a hydraulic transmission. The robot uses a Real Time Kinematic Differential Global Positioning System to determine both position and orientation relative to the path. The deviation of the robot to the desired path is supplied to two high level controllers minimizing the orthogonal distance and orientation to the path. Wheel angle setpoints are determined from inversion of the kinematic model. At low level each wheel angle is controlled by a proportional controller combined with a Smith predictor. Results show the controller performance following different paths shapes including a step, a ramp, and a typical headland path. A refined tuning method calculates controller settings that let the robot drive as much as possible along the same path to its setpoint, but also limit the gains at higher speeds to prevent the closed loop system to become unstable due to the time delay in the system. Mean, minimum and maximum orthogonal distance errors while following a straight path on a paving at a speed of 0.5 m/s are 0.0, ?2.4 and 3.0 cm respectively and the standard deviation is 1.2 cm. The control method for four wheel steered vehicles presented in this paper has the unique feature that it enables control of a user definable position relative to the robot frame and can deal with limitations on the wheel angles. The method is very well practical applicable for a manufacturer: all parameters needed are known by the manufacturer or can be determined easily, user settings have an easy interpretation and the only complex part can be supplied as a generic software module.

Feedback control of the vortex-shedding instability based on sensitivity analysis

Abstract: In the present work, a simple proportional feedback control is designed to suppress the vortex-shedding instability in the wake of a prototype bluff-body flow, i.e., the flow around a square cylinder confined in a channel with an incoming Poiseuille flow. Actuation is provided by two jets localized on the cylinder surface and velocity sensors are used for feedback control. This particular configuration is a pretext to propose a more general strategy for designing a controller, which is independent of the type of actuation and sensors. The method is based on the linear stability analysis of the flow, carried out on the unstable steady solution of the equations, which is also the target flow of the control. The idea is to use sensitivity analysis to predict the displacement in the complex plane of some selected eigenvalues, found by the linear stability analysis of the flow, as a function of the control design parameters. In this paper, it is shown that the information provided by only sensitivity analysis ...

Increasing the Accuracy of Digital Force Control Process Using the Act-and-Wait Concept

Abstract: Proportional gains are to be increased in force control processes in order to reduce the force error. However, the control process may become unstable for large gains due to the digital and delay effects. In this paper, the act-and-wait control concept is compared with the traditional, continuous control concept for a digital force control model with proportional feedback subject to a short, one sample unit feedback delay. Both concepts are implemented in an experimental setup. It is shown that the proportional gain can be increased significantly without losing stability when the act-and-wait controller is used; thus, the force error can effectively be decreased this way. The results are confirmed by experiments.

Liquid-Based Cooling System For Data Centers Having Proportional Flow Control Device

Abstract: A liquid-based cooling system provides a method of supplying a heated coolant fluid at a relatively constant temperature and pressure to one or more heat driven engines, such as adsorption chillers or heat pumps, by utilizing a proportional flow control device in association with each of a plurality of heat-producing electronic components to optimize the output of a plurality of liquid-cooled cold plates operatively mounted on such plurality of heat-producing electronic components. The proportional flow control devices may be electro-mechanical or solid state proportional control valves for water flow control. The proportion flow control devices are operatively connected to be actuated based upon the electrical signals typically generated to control the variable cooling fans of the electronic components.

Quad rotor arial robot dynamic modeling and configuration stabilization

Abstract: In this paper, we propose a nonlinear control scheme for attitude stabilization of 4 rotor vertical take off and landing (VTOL) aerial robot known as the quad rotor rotorcraft. A nonlinear dynamic model of a 6 DOF underactuated quad rotor aerial robot is derived based on Newton-Euler formalism. The proposed controller is based upon the compensation of the Coriolis and gyroscopic torques and the use of a PD feedback structure for altitude and yaw channel and the use of backstepping based PID technique for the rotational control, where the proportional action is in terms of the Euler angels and the derivative action is in terms of the airframe angular velocity. We used optimization algorithm to get the proper design parameters values. With the compensation of the coriolis and gyroscopic torques, our controller provides asymptotic stability for our problem. Also our nonlinear control technique gives the ability to overcome the problem of non minimum phase. Simulation results are also provided to show the effectiveness of the proposed controller.

Zero Vibration On–off Position Control of Dual Solenoid Actuator

Abstract: Solenoids are low-cost high-speed nonlinear actuators commonly used in switching mode. This paper presents a dual-solenoid actuator system for high-speed positioning applications. A novel control method that combines on-off control and input shaping is used to obtain low-vibration smooth transients when compared with traditional proportional and integral control and on-off control. Simulation results and experimental data confirm that this dual-solenoid position actuator with the novel control method is effective and practical.

High-Performance Feedback Control of Electromagnetic Vibratory Feeder

Abstract: In this paper, a high-performance feedback controller for an electromagnetic vibratory feeder is proposed. An electromagnetic actuator is driven by a switching circuit with pulsewidth as the control variable. The controller structure consists of a proportional-integral controller combined with a state observer. The controlled variable is the resonant frequency vibration amplitude obtained in real time from the state observer. The use of the state observer allows fast disturbance rejection and reference tracking in both directions (amplitude increase and decrease). Simulations and experimental results from the real device are presented.