A parameter space approach to constrained variance PID controller design

This paper presents a parameter space approach to constrained variance and minimum variance PID controller design for LTI models. The technique is based on rational transfer functions of the plant and noise models. Loci corresponding to a fixed variance can be mapped into parameter planes for PID and PI type controllers to graphically display regions which satisfy the constraint, thereby guiding a design to appropriate controller gains. Requirements for tracking regulation can be readily achieved without excessively increasing the output variance. The usual advantages of parameter space techniques apply where other design criteria may be superimposed, allowing multiple objectives to be achieved non-conservatively. The superposition of the parameter space boundaries from existing robust control techniques thus allows non-conservative robust minimum variance PID design. A design example compares the technique to an algebraic minimum variance design using an integrator when tracking is required.     

Algebraic approach to stochastic optimal digital controller design

A new approach to the design of an optimal controller for a system described by its transfer function (SISO case) is presented. The stochastic or deterministic disturbances as well as the noise contaminating measured output are described by the spectral density. The objective is the minimization of a linear combination of quadratic measures of system input and output on an infinite time range. The basic idea is the determination of a new optimization domain inside which asymptotic stability of the system, considering its closed-loop structure, is guaranteed. The solution uses polynomial algebraic techniques and requires only the solution of the system of two polynomial equations, the coefficients of which are obtained from spectral factorization. The system may be unstable and/or non-minimal phase and possible measurement noise may be coloured.     

A new design for a PID plus feedforward controller

In this paper, a new design and tuning procedure for a PID plus feedforward controller is proposed. It consists of determining a feedforward signal in order to achieve a predefined process output transition time assuming a first order plus dead time model of the process. Then, the PID parameters are tuned by any conventional method in order to assure a good load disturbance rejection and the reference signal to the closed-loop system is obtained by filtering appropriately the set-point step signal. Simulation and experimental results show that the method outperforms the typical (inverse) model-based approach despite its simplicity and it is therefore suitable to implement in Distributed Control Systems as well as in single-station controllers.     

Computational intelligence approach to PID controller design using the universal model

Despite the popularity of PID (Proportional-Integral-Derivative) controllers, their tuning aspect continues to present challenges for researches and plant operators. Various control design methodologies have been proposed in the literature, such as auto-tuning, self-tuning, and pattern recognition. The main drawback of these methodologies in the industrial environment is the number of tuning parameters to be selected. In this paper, the design of a PID controller, based on the universal model of the plant, is derived, in which there is only one parameter to be tuned. This is an attractive feature from the viewpoint of plant operators. Fuzzy and neural approaches - bio-inspired methods in the field of computational intelligence - are used to design and assess the efficiency of the PID controller design based on differential evolution optimization in nonlinear plants. The numerical results presented herein indicate that the proposed bio-inspired design is effective for the nonlinear control of nonlinear plants.     

A simple robust PI/PID controller design via numerical optimization approach

This paper presents a simple but effective method for designing robust PI or PID controller. The robust PI/PID controller design problem is solved by the maximization, on a finite interval, of the shortest distance from the Nyquist curve of the open loop transfer function to the critical point-1. Simulation studies are used to demonstrate the effectiveness of the proposed method.     

Gain-scheduled PID controller design

Gain scheduling (GS) is one of the most popular approaches to nonlinear control design and it is known that GS controllers have a better performance than robust ones. Following the terminology of control engineering, linear parameter-varying (LPV) systems are time-varying plants whose state space matrices are fixed functions of some vector of varying parameters. Our approach is based on considering that the LPV system, scheduling parameters and their derivatives with respect to time lie in a priori given hyper rectangles. To guarantee the performance we use the notion of guaranteed costs. The class of control structure includes centralized, decentralized fixed order output feedbacks like PID controller. Numerical examples illustrate the effectiveness of the proposed approach.     

A novel design of high-sensitive fuzzy PID controller

A hybrid model is designed by combining the genetic algorithm (GA), radial basis function neural network (RBF-NN) and Sugeno fuzzy logic to determine the optimal parameters of a proportional-integral-derivative (PID) controller. Our approach used the rule base of the Sugeno fuzzy system and fuzzy PID controller of the automatic voltage regulator (AVR) to improve the system sensitive response. The rule base is developed by proposing a feature extraction for genetic neural fuzzy PID controller through integrating the GA with radial basis function neural network. The GNFPID controller is found to possess excellent features of easy implementation, stable convergence characteristic, good computational efficiency and high-quality solution. Our simulation provides high sensitive response (∼0.005 s) of an AVR system compared to the real-code genetic algorithm (RGA), a linear-quadratic regulator (LQR) method and GA. We assert that GNFPID is highly efficient and robust in improving the sensitive response of an AVR system.     

一种新型数字式手柄控制器的设计

介绍了几种数字式手柄控制器的优缺点,针对某数字伺服系统实际需求,设计了一种具有CAN总线通信功能的新型数字式手柄控制器。根据角速度积分原理,详细讨论各部分硬件组成电路,给出软件流程。通过实验比较和效果分析,该手柄不仅能输出任意角位置,还能实现跟踪角速度命令的连续变化。其结构易于实现,开发成本低,有较高灵活性和稳定性,充分发挥软硬件结合的潜力作用。在雷达跟踪、周视监控等数字式伺服控制中有巨大应用前景。     

A new approach to auto-tuning of PID controllers

Delayed state variable filters are implemented for the estimation of parameters of monotone open-loop processes that can be approximated by a first-order lag coupled with a time delay. Based on the delayed filtered step output response, and the first and second-order derivatives, a new estimation procedure has been derived for on-line estimation of the corresponding static process gain, the apparent dead time and the apparent time constant. A new PID tuning formula is formed that is based on the placement of the open-loop zeros related to the apparent time constant and time delay, to give a controlled system with a damping of 0-5 or a maximum overshoot of approximately 16-3%. Extensive simulation studies have also been carried out to relate the controlled output step response to the open-loop system parameters, which could then be re-applied in closed loop retuning of PID controllers. Efforts have also been made to apply the tuning technique to the control of multivariable systems. Simulations are included to illustrate the concepts.     

PID controller design for robust performance

This note is devoted to the problem of synthesizing proportional-integral-derivative (PID) controllers for robust performance for a given single-input-single-output plant in the presence of uncertainty. First, the problem of robust performance design is converted into simultaneous stabilization of a complex polynomial family. An extension of the results on PID stabilization is then used to devise a linear programming design procedure for determining all admissible PID gain settings. The most important feature of the proposed approach is that it computationally characterizes the entire set of the admissible PID gain values for an arbitrary plant.     

A data driven subspace approach to predictive controller design

This paper shows the design of predictive controllers using the predictor, designed from the subspace matrices, obtained directly from the input/output data. The model-free design approach presented in the literature so far does not include all the important predictive control features such as inclusion of an integrator for offset-free control, constraint handling, feedforward option and a means of tuning the controllers through the disturbance model; these features are important for practical applications and hence, amongst other issues, addressed in this paper. The proposed predictive controller is demonstrated on multivariate systems using MATLAB simulations and an application on a pilot scale process.     

A passivity approach to controller design for quasi-resonant converters

In this paper, the passivity-based approach to controller design for the boost and buck quasi-resonant converters is addressed. Quasi-resonant converters use a soft switching method where the power devices switch at zero voltage or zero current, resulting in low switching loss and high power density. The controller design is carried out using the generalized state space average equations of these converter circuits and the celebrated “energy shaping plus damping injection” ideas of the passivity-based approach. Both direct and indirect output voltage regulation schemes are studied. Simulation results are presented to illustrate the features of the proposed controllers.     

Design of a digital PID stand-alone single-loop controller

A digital PID algorithm is proposed for the control of a wide class of processes that may be characterized by steady-state gain, time constant, and transport lag. The grapho-analytical pole-placement procedure proposed enables the designer to make rapid and straightforward adjustments to the controller parameters with respect to the desired system accuracy, speed of continuous time response, and stability margin. A sensitivity analysis procedure is developed for investigating the effects of transport lag on the system dynamic behaviour in the sampled-data control system considered     

一种基于LabVIEW的PID控制器设计的方法

利用LabVIEW虚拟仪器开发平台,设计了一个程序,可以对3阶以内的线性被控对象快速的确定PID控制器的各个参数,完成PID控制器的设计.同时,可以给出控制系统开环或者闭环的阶跃响应.     

A direct method for multi-loop PI/PID controller design

Difficulties caused by the interactions are always encountered in the design of multi-loop control systems for MIMO processes. To overcome the difficulties, a multi-loop system is decomposed into a number of equivalent single loops for design. For each equivalent single loop, an effective open-loop process (EOP) is formulated without prior knowledge of controller dynamics in other loops, and, hence, controller can be designed directly and independently. Based on the derived EOPs, a model-based method aims at having reasonable gain margins (e.g. 2) and phase margins (e.g. ≈60°) are presented to derive multi-loop PI/PID controllers. This proposed method is formulated in details for the EOPs of 2-loop systems. Extension to higher dimensional systems needs further simplification and is illustrated with formulation for 3-loop systems. Simulation results show that this presented method is effective for square MIMO processes, especially, for low dimensional ones.     

旋转压实仪参数自整定数字PID控制器的设计

为了使旋转压实仪对高等级公路路面材料一沥青混合料的性能试验达到标准要求,采用理论分析与试验相结合的方法研究了旋转压实仪对沥青混合料试样压实过程中压实力的变化特征,获得了参数自整定压实力数字PID控制器的设计方法和设计参数.在压实过程的初始阶段每转对控制器参数进行自整定,确定了0.25秒的最佳采样频率.根据研究结果设计的数字控制器经过多次实际试验验证,结果表明其达到了标准要求的控制精度.     

A new decentralised controller design method with application to power-system stabiliser design

It is known that decentralised stabilising controller design for a large-scale system can be translated into an equivalent problem of decentralised controller design for a multi-input multi-output (MIMO) control system. This paper shows that, subject to a condition based on the structured singular values, each local controller can be designed independently. The stability condition for the overall system can be easily stated as the achievement of a sufficient interaction margin, introduced in earlier work, together with a sufficient gain and phase margin, defined using classical feedback theory during each independent design. The suggested design approach is applied to the decentralised design of a power-system stabiliser for a model of a practical 10-machine power system. The potentials and limitations of the suggested design approach in its current form, and possibilities for further research, are also discussed in this paper.     

A new PID controller tuning method based on multiple integrations

The magnitude optimum (MO) technique provides a non-oscillatory closed-loop response for a large class of process models. However, this technique is based on a transfer function model that requires precise process identification and extensive computations. In the present paper, it is shown that a close relation exists between multiple integrations of the process step response and the MO criterion. Due to this relation, the MO criterion can be more simply achieved. Some practical guidelines for performing multiple integrations and for re-tuning controller parameters are also given.     

Type-III closed loop control systems-Digital PID controller design

The problem of tuning digital PID controllers for type-III control loops is investigated in this work. Type-III control loops are capable of achieving perfect tracking of step, ramp and parabolic reference signals with zero steady state position, velocity and acceleration error. The proposed PID control law involves any dominant time constants of the process itself, and any parasitic dynamics introduced by both the process and the controller, i.e. time delays within the closed control system. The development of the proposed control law takes place in the frequency domain and basis of the theory is the principle of the Magnitude Optimum criterion. The final control law consists of closed form expressions which involve also the controller's sampling time T_s. The potential of the proposed theory is justified for the control of several benchmark process models throughout simulation examples. The affect of the choice of the controller's sampling time is investigated further to the step and frequency response of the control loop both for the output of the control loop and the controller's command signal.