Posicast Control Research Articles

Hybrid passive vibration control of lightweight manipulators

Passive vibration control methods in the literature are known to be highly sensitive to dynamic system parameters and are generally applied one by one. Therefore, their effectiveness in suppressing vibration control is limited. In this work, hybrid passive control (HPC) by integrating the Posicast control (PC) and the motion parameters-based control (MPC) is developed to suppress the during-motion vibrations (DMV) and residual vibrations (RV) of a single-link lightweight manipulator with a payload. PC is designed as a three-step cycle using the first natural frequency and damping ratio of the manipulator. MPC is designed by determining the time parameters of the motion profiles based on the first natural frequency of the manipulator. HPC simulations are performed on MATLAB, creating a Simscape model of the manipulator. Then, the proposed control method is tested in experiments. The prepared hybrid motion inputs actuate the servomotor while the displacements are measured, using a laser sensor at the tip of the manipulator. DMV and RV responses and their RMS values reveal that suppressing the vibration amplitudes efficiently. MPC is mostly effective in eliminating RV, whereas PC is sensitive to DMV as well. HPC combines these methods by eliminating their disadvantages and highlighting their advantages. Moreover, it is also successful in cases where the deceleration time of the trapezoidal input signal is single times half of the natural period, unlike MPC.

Modelling, Simulation, and Implementation of Effective Controller for KY Stepping Up Converter

This paper studies on a new Hybrid Posicast Control (HPC) for Fundamental KY Boost Converter (FKYBC) worked in Continuous Current Mode (CCM). Posicast is a feed-forward compensator. It reduces the overshoot in the step result of the flippantly damped plant. But the conventional controller approach is sensitive owing to the changes in the natural frequency. So, as to reduce this undesirable sensitivity and load potential control of FKYBC, a HPC is designed in this article. Structure of HPC is posicast with feedback loop. The independent computational time delay is the main design function of the posicast. The enactment of the FKYBC with HPC is confirmed at various operating regions by making the MATLAB/Simulink and experimental model. The posicast function values are implemented in Arduino Uno-ATmega328P microcontroller. The results of new HPC have produced minimal noise in control signal in comparison with traditional PID control.

Modified Posicast Control Design Method Based on the Parameters of a Fractional Order System

Abstract In this study, a novel design method for half-cycle and modified posicast controller structures is proposed for a class of the fractional order systems. In this method, all required design variable values, namely, the input step magnitudes and their application times are obtained as functions of fractional system parameters. Moreover, empirical formulas are obtained for the overshoot values of the compensated system with half-cycle and modified posicast controllers designed utilizing this method. The proposed design methodology has been tested via simulations and ball balancing real-time system. It is observed that the derived formulas are in coherence with outcomes of the simulation and real-time application. Furthermore, the performance of modified posicast controller designed using proposed method is much better than other posicast control method.

Non-overshooting control of linear system by a simple asymptotic gain scheduling method

In this paper, a simple yet effective method has been raised for non-overshooting control of linear higher order plant. It is based on Posicast control, asymptotic gain scheduling and dominant pole placement by modified proportional-integral-derivative (PID) controllers, including PI-D, I-PD, PI-PD and PD-PID. The control system is composed by two closed-loops, that is, the inner loop where modified PID controllers are used to stabilize the plant by dominant pole placement, and the outer loop where asymptotic gain scheduling is used to shape the non-overshooting step response. Use of the modified PID controllers is the key to secure success of asymptotic gain scheduling, for dominance of the specified poles and phase lag dominant pole control system can be designed by these controllers in the inner loop. Three numerical examples are used to validate the method; results show that a non-overshooting control with relatively short settling time and small undershoot can be realized.

PID Posicast Control for Uncertain Oscillatory Systems: A Practical Experiment

Half-cycle Posicast Control is currently used in a vast range of applications. Although the proved benefits of this technique, one of its major disadvantages concerns model uncertainties. This has motivated the development and integration of robust methods to overcome this issue. In this paper, a practical experiment for auto-tuning of a two degrees of freedom control configuration using a Half-Cycle Posicast pre-filter (or input-shaping), and a PID controller under parametric variations is presented. The proposed method requires using an oscillatory system model in an auto-tuning control structure. The error derivative among the model and system output is used to trigger both the identification and retuning procedure. The proposed method is flexible for choosing identification plus optimization methods. Practical results obtained for electronic filter plants suggest improved performance for the considered cases.

Design of a New Controller for an Inverter Operation in Transitional Regime Within a Microgrid

This paper is presented the modeling and design through simulations of two controllers for a single phase inverter for operation in island mode within a microgrid. In particular, a small signal model of a single-phase inverter and controller design for the current loop and voltage loop inverter are presented. For this operation mode is due of fulfilling the goal of maintaining the waveform amplitude and frequency of the voltage signal to be fed to the load. Therefore, this application is distinguished the design of a new control configuration based on the inclusion of a Posicast control within a proportional integral-proportional (PI-P) control configuration. Being goal of this controller, improve the transient response of the inverter and present a better disturbance rejection.

Posicast control of structures using MR dampers

Summary In this article, a novel application of a semi active posicast control scheme for structures with magneto-rheological (MR) dampers is presented. MR dampers are considered to be highly promising of semi-active control systems, which are becoming increasingly popular for alleviating the effects of dynamic loads on civil engineering structures because they combine the merits of both passive and active control systems. The main contribution of this article relates to the design, application, tuning and performance evaluation of the novel posicast control scheme for structural control. The efficiency of the suggested control strategy was evaluated by performing numerical simulations of a benchmark three-storey building with an MR damper, rigidly attached between the first floor and the ground. The damper's behaviour was simulated using the Bouc–Wen model. Seven evaluation criteria were used to assess the performance of the proposed posicast control scheme in reducing the excited structure's responses to dynamic loading. The simulation's results indicated that the posicast control scheme had significant advantages over conventional alternatives in terms of performance and efficiency. Copyright © 2016 John Wiley & Sons, Ltd.

2206 平面駆動形リニアパルスモータの応答特性の改善(センサ・アクチュエータ(2))

A planar-type tripod parallel mechanism has a larger motion space and greater tilt angles. The tripod parallel mechanism for a motion base has three legs translating on the ground. A scale model of the tripod parallel mechanism with planar actuators is designed and fabricated. The planar actuation is performed by two-axis Sawyer-type linear motors with open loop control, free to move above the ground on aerostatic bearings. A posicast control scheme for the three planar actuators is applied to improve a step response behavior. The experimental results show that the control algorithm has good positioning performance.

FPGA Implementation of an Optimal IGBT Gate Driver Based on Posicast Control

In this paper, we propose an insulated gate bipolar transistor (IGBT) gate driver that provides an optimal gate signal to manage the IGBT switching mechanism, without the need of a feedback current measurement across the parasitic inductance of the circuit. Our approach is based on the Posicast method, which allows determining an optimal gate signal shape from pulses whose characteristics are determined from the IGBT model. Experimental results demonstrate the effectiveness of the proposed method to minimize electrical switching constraints.

Composite adaptive posicast control for a class of LTI plants with known delay

Many potential applications of adaptive control, such as adaptive flight control systems, require that the controller have high performance, stability guarantees, and robustness to time delays. These requirements typically lead to engineering trade-offs, such as a trade-off between performance and robustness. In this paper, a new Composite Adaptive Posicast Control (CAPC) framework is proposed for linear time-invariant (LTI) plants with input-matched parametric uncertainties and known delay. The CAPC architecture uses a combination of several modifications to the typical direct model reference adaptive control (MRAC). The described approach is a nonlinear controller design that explicitly accounts for known time delay. The stability of the overall closed-loop system can be guaranteed using nonlinear analysis tools. The benefits of the CAPC approach are explored using a simulation of the longitudinal dynamics of a fixed-wing aircraft. Comparison studies are presented for 80 ms and 250 ms time delay cases.

Posicast control of a class of fractional-order processes

AbstractThe number of studies on the control of fractional-order processes—processes having dynamics described by differential equations of arbitrary order—has been increasing in the past two decades and it is now ubiquitous. Various methods have emerged and have been proven to effectively control such processes—usually resulting in fractional-order controllers similar to their conventional integer-order counterparts, which include, but are not limited to fractional PID and fractional lead-lag controllers. However, such methods require a lot of computational effort and fractional-order controllers could be challenging when it comes to their synthesis and implementation. In this paper, we propose a simple yet effective delay-based controller with the use of the Posicast control methodology in controlling the overshoot of a fractional-order process of the class $$\mathcal{P}:\left\{ {P\left( s \right) = {1 \mathord{\left/ {\vphantom {1 {\left( {as^\alpha + b} \right)}}} \right. \kern-\nulldelimiterspace} {\left( {as^\alpha + b} \right)}}} \right\}$$ having orders 1 < α < 2. Such controllers have proven to be easy to implement because they only require delays and summers. In this paper, the Posicast control methodology introduced in the past few years is modified to minimize the overshoot of the processes step response to a level that is acceptable in control engineering and automation practices. Furthermore, proof of the existence of overshoot for such class of processes, as well as the determination of the peak-time of the open-loop response of a fractional-order process of the class P is presented. Validation through numerical simulations for a class of fractional-order processes are presented in this paper.

Underdamped Second-Order Systems Overshoot Control

The paper addresses the problem of decreasing the overshoot for underdamped second-order systems. A new technique to control the overshoot is proposed, which is based on Posicast control and proportional integral and derivative (PID) control, which performs switching between two controllers. The aim is to use open-loop feedforward control to increase tracking performance and PID control to deal with disturbance rejection. It has been shown that the proposed control scheme can have some advantages over the classical approaches without switching capabilities.

Application of the Posicast control method to static shunt compensators

In this paper, the Posicast control method is used for decreasing the reactive power oscillations of static shunt compensators. Shunt compensators such as the static synchronous compensator (STATCOM) and static VAR compensator (SVC) are considered to be FACTS devices. The applied control method decreases the amount of oscillations in the outputs of STATCOM and SVC considerably, with fast damping. In this paper, a PI controller is added to the model to decrease the sensitivity of the Posicast controller to the parameter variations and plant model mismatch. Simplicity and applicability are the main features of this controller. The model is simulated in a MATLAB/Simulink environment.

Posicast control within feedback structure for a DC–DC single ended primary inductor converter in renewable energy applications

In this paper, modeling, analysis, design, simulation and control of a single ended primary inductor converter (SEPIC) are discussed for renewable energy applications. Because the traditional control methods such as proportional–integral–derivative (PID) and classical half-cycle Posicast controllers based on feedforward are sensitive to noise and variations in natural frequency, a Posicast control with feedback structure is proposed and designed to reduce or rejection undesirable sensitivity greatly, to suppress measurement noise and to eliminate the overshoot in the output response. The SEPIC converter is modeled using average value modeling analysis. Dynamic modeling and simulation are accomplished using MATLAB Simulink™ 7.2.

Posicast Control with Nonzero Initial Conditions

This work shows an approach to solve the nonzero initial conditions posicast control. This control has been studied for systems which are lightly damped like the half-cycle ones. However these techniques have not had special attention for applying their approaches when the initial conditions are not zero. This note presents a methodology for solving this problem with a basic analysis in the complex domain and the results shown with simulations prove the efficiency of our approach.

Desensitized Jerk Limited-Time Optimal Control of Multi-Input Systems

The problem of designing jerk limited-time optimal control proe les for rest-to-rest maneuvers of e exible structures with multiple actuators is addressed. The problem formulation includes constraints to cancel the poles corresponding to the rigid-body mode and e exible modes of the system and to satisfy the boundary conditions of the rest-to-rest maneuver. Further constraints can be added to increase robustness to parametric uncertainties of the plant. The technique proposed is applied to a three-mass/two-spring system and the evolution of the shape of the control proe le as a function of jerk is illustrated. I. Introduction T HERE has been extensive research in the e eld of vibration control of slewing e exible structures. The knowledge obtained throughoutthisresearchhasbeenappliedtoawidevarietyofcontrol problems, including, but not limited to, maneuvering of large space structures, 1 e exiblearmrobots, 2 computerdiskdrives, 3 andcranes. 4 In most of these applications, the objective of the controller is to minimize the maneuver time with quiescent e nal states. Robustness tomodelingerrors,limitsonfuelconsumed,maximumdeformation permitted,andso on,havebeenincludedintheproblemformulation as additional constraints. Research in the e eld of input shaping was motivated by Smith’ s development of the Posicast Control. 5 The sensitivity of these controllers to uncertainties in damping and frequencies of the modes was addressed by Singer and Seering, 6 and the resulting pree lter was referred to as an input shaper. Singh and Vadali 7 illustrated that a time-delay pree lter that cancels the underdamped poles of the system results in the same control proe le as the input shaped controller. They also illustrated that the use of a series of time-delay e lters results in increased robustness to modeling errors. Various other approaches, which include forcing the derivative of the sensitivity curve at the nominal values of the model parameters to zero and designing input shapers that maximize the uncertain region where the residual vibration is less than a prespecie ed quantity, 8 have been investigated in the interest of desensitizing the pree lter with respect to modeling errors. Techniques to desensitize the timeoptimal control proe le have been developed by Liu and Wie 9 and Singh and Vadali. 10 A very recent approach to the design of desensitized time-delay e lters is a minimax formulation proposed by Singh. 11 All of the aforementioned approaches assume that the actuator can track step inputs, which is equivalent to requiring ine nite jerk control proe les. Jerk is indicative of the time rate of change of the inertia forces and is a measure of the impact levels that can excite unmodeled dynamics, which is of concern in the control of e exible structures. Bhat and Miu 3 study the problem of designing control proe les, minimizing a cost function that is the time integral

High-Speed Positioning of Pneumatic Robot Using Learning Posicast Control.

In this study our objective is high-speed positioning of a pneumatic robot. To realize a high-speed drive, the control algorithm should be as simple as possible to reduce the calculation time of control input. A posicast control scheme may be considered an effective control strategy which satisfies such a requirement. However, the original scheme is not sufficient for a pneumatic drive system which is usually of an order higher than the second, and has an operating delay in the electro pneumatic valve, etc. We improve the original posicast control scheme so that it can be applied to positioning of the pneumatic robot. In this control scheme, the regulation of both the height and the switching time of reference input is important. Thus, we provide a learning function which can regulate these parameters with respect to the configuration of the last response during repeated operation. We describe the proposed control algorithm and discuss its availability through simulations and experiments.

Application of an approximate time delay to a Posicast control system†

The performance of a method of producing relatively long time delays, using truncated Fourier series expansion, applied to a Posicast control system was investigated. The controlled system had a long natural period and was lightly damped. Both the Posicast control and the system were simulated on an analogue computer. The response of the system to step inputs with Posicast showed dramatic improvement over the uncompensated system. The overall system approached the theoretical response of an ideal Posicast system. A series of runs was made with successively cruder approximations of the delay function. Response was not seriously degraded until the frequency of the truncated terms became comparable to the upper 3 dB frequency of the controlled system. Other waveforms were tested, including sine, square, sawtooth and quasi-random signals. In all cases, the performance of the system was well behaved. The approximate method of delay, therefore, offers a means of implementing Posicast control with systems requir...

Posicast Controllers using Switching Techniques

In a lightly damped control system rise time is small but large overshoot and prolonged oscillations present in the output are unwanted. If such a system is required to produce dead beat response, input is to be modified suitably by a prefilter or controller which is generally called possicast controller. Posicast control technique first proposed by O. J. M. Smith in 1957 for producing dead response with the help of delay lines was found satisfactory for second order systems. Zaborszky in 1958 on the same lines proposed a simple nonlinearized system using relays. This too was suitable for second order systems only. By changing system dynamics suitably it is possible to get dead beat response for third order and higher order systems also. A detailed study of posicast control system by N. G. Nath and A. K. Choudhury (1969) have shown that it is possible to apply posicast principle to higher order systems also. For even order systems a positive casting of the system input is required, while for odd order sys...

Posicast and negicast control systems†

A possibility of obtaining dead beat response of a class of high-order control systems by adopting the technique of a single step control of the input step command is described in this paper. For achieving the desired response by such input processing techniques, the possibility demands that configurations of high-order systems be of suitable forms and the method of control necessitates positive casting of the system input like the posicast control technique in ease of oven-order systems and negative casting of the input in case of odd–order systems. The system configurations and the forms of the processed input signals in those cases have separately been investigated. The speed of the response avoiding saturated operation of such compensated systems has been studied. The effect of an improper switching operation in casting the system input has also been investigated. The results of the above studios made on the simulated systems have been given.