Earticle

This paper presents in-process compensation methodology to eliminate cutter runout and improve machined surface quality. The cutter runout compensation system consists of the micro-positioning mechanism with the PZT (piezo-electric translator) which is embeded in the sliding table to manipulate the radial depth of cut in real time. For the implementation of cutter runout compensation methodology. cutting force adaptive control was proposed in the angle domain based upon PI (proportional-integral) control strategy to eliminate chip-load change in end milling process. Micro-positioning control due to adaptive acuation force response improves the machined surface quality by compensation or elimination of cutter runout induced cutting force variation. This results will provide lots of information to build-up the precision machining technology.

This paper presents the in-process runout compensation methodology to improve the surface quality of circular contouring cut in end milling process. The runout compensation system is based on the manipulation of workpiece position relative to cutter in minimizing the cutting force oscillation at spindle frequency. the basic concept of this approach is realized on a end milling machine whose machining table accommodates a set of orthogonal translators perpendicular to the spindle axis. The system performed that measuring the runout related cutting force component, formulating PI controlling commands, and the manipulating the workpiece position to counteract the variation of chip load during the circular contouring cut. To evaluate the runout compensation system performance, experimental study based on the implementation of two-axes PI force control is presented in the context of cutting force regulation and part surface finish improvement.

In the recent years, the demand for the grid connected inverters has increased immensely as they act as an interface between the photo voltaic systems and the utility. The focus of this research article is to model and analyze the design characteristics of a two level, pulse width modulated, grid connected inverter using Matlab. The Proportional Integral and Proportional Resonant controller are being investigated and the performance of these controllers is being discussed. These simulation results show that the proportional resonant controller is able to mitigate the harmonics and perform satisfactory as compared to Proportional integral controller under the same harmonic conditions.

The pure electric vehicle with dual-energy storage system is driven under complex driving states. Owing to its nonlinear model, the fuzzy control is usually used in energy distribution. It is difficult for the conventional fuzzy controller without integral part to eliminate the static errors. Its control effect is not satisfactory. The required power minus actual power is the deviation. The self-adaptive fuzzy PI control adjusts the deviation values through tuning the parameters of PI controller in real time. Its control effect is satisfactory. The results of simulation experiment indicate that the self-adaptive fuzzy PI control is more economical than the fuzzy control under the same driving states.

Transmission accuracy of traditional Transmission Control Protocol (TCP) in high-bandwidth wireless network is low, and its efficiency is low. For these problems, the thesis proposes a virtual router model from the perspective of end-to-end, and on this basis of using the classical control theory the thesis proposes an end-to-end PI rate control algorithm--SPI RCP on the transmitter. According to the RTT information collected by the transmitter, the real-time queue length of virtual router is calculated, and by using the PI control theory the transmission rate of the transmitter is calculated to make the queue length of the bottleneck node is stabilized at a target location, at the same time to avoid the wrong adjust of congestion windows caused by wireless link packet loss. The end-to-end design of new algorithm saves router resources, enhances the stability of the queue length, and reduces network congestion packet loss. The simulation results show that compared with the traditional congestion control protocol, the new mechanism can better control the queue length of the router and improve the stability and network throughput of the network load.

Predictive functional control and multivariate PI predictive functional control is presented based on state space equation for non-linear, fast time-varying, multivariable coupling near-space vehicle attitude control system. Transforming nonlinear optimal problems into online optimization in the linear time-invariant systems and solve the control law in a rolling way. Lyapunov’s second stability theorem proved that the solved control law can ensure a certain degree of robustness of the closed-loop system. Tuning parameters of multivariable PI predictive functional controller based on particle swarm optimization algorithm. Designed near-space vehicle attitude controller and simulate it. Results show that both of the two control strategy can get good control performance, comparatively, multivariable PI predictive functional control has a better control effect. It has the advantages of non-overshoots, faster response, and smaller steady state error etc.

To minimize the longitudinal strip thickness error in the hydraulic cold rolling industries and improve traditional AGC control scheme on this problem, we put forward a secure gauge control system based on Advanced RISC Machines (ARM) and intelligent PI control strategy. The traditional automatic gauge control (AGC) scheme depended on personal experience about the parameters. The new gauge control system decreases the longitudinal strip thickness error via fuzzy control and ARM-based computing. Besides, this new system can be smaller than the traditional AGC system, and so is much easier to transport. The Fuzzy control scheme can increase the robustness of the ARM-based gauge control system against some disturbances. The Matlab-based experimental simulations show that our secure gauge control system with Fuzzy control and ARM is better than the traditional one.

The use of smart devices worldwide has been increasing day by day and its applications based on IoT have been also extended. But the power control system requires complicated control and processing information from the various sensors in practice. One of the best ways to save the power consumption is to manage elec-trical equipment individually on the Internet. In this paper, remote power control system for managing the power through the relay switch module via Python server was implemented by using Raspberry Pi. The pro-posed power control system can be used anywhere over the Internet.

A compound control method of sliding-model variable structure and fractional order PIλDμ(SMC-FOPID) is proposed based on such factors as strong nonlinearity, time-varying parameters, disturbance, time delay, as well as the rapidity of a working clutch system in the process of automated manual transmission (AMT) clutch control. The self-tuning of the composite weight coefficient is realized by the fuzzy inference algorithm with single input and output. The coordinated control of the SMC-FOPID is realized through the real-time adjustment of the composite weight coefficient. The control performances of proportional-integral-derivative (PID), fractional order PIλDμ (FOPID), sliding-model variable structure control (SMC), and SMC-FOPID were compared based on the performance index integral of time multiplied by absolute value of error (ITAE) to study the position tracking of an AMT clutch in the working process. The simulation result showed that the SMC-FOPID control method had higher synthetic control performance compared with the PID, FOPID, and SMC control methods. The feasibility and superiority of the position tracking of an AMT clutch with an SMC-FOPID controller were verified.

This paper proposes new fuzzy type sliding mode controller for multi-DOF joints to reduce/eliminate motor vibration. The fuzzy (PI+D)2 single-input single-output (SISO) fuzzy system is applied to modify each element of the control in a sliding mode controller. The proposed method is designed based on the Lyapunov method. Mathematical proof for the stability and the convergence of the system is presented. Various operation situations such as the set point control and the trajectory control are simulated. The simulation results demonstrate that the chattering and the steady state errors, which usually occur in the classical sliding mode control, are eliminated and satisfactory trajectory tracking is achieved.

The performance of an inverter-driven water-to-water heat pump with an electronic expansion valve (EEV) was measured as a function of compressor frequency, load conditions, and EEV opening. Based on the test results, a controller using proportional integral (PI) feedback or PI feedforward algorithm was designed and tested to investigate capacity modulation and transient response control of the system. Although the relation between superheat and EEV opening of the heat pump showed nonlinear characteristics, a control gain obtained at the rated frequency was applicable to various operating conditions without causing large deviations. When the simple PI feedback control algorithm was applied, a large overshoot of superheat and wet compression were observed due to time delay effects of compressor frequency. However, applying PI feedforward control scheme yielded better system performance and higher reliability, compared to the PI feedback algorithm.

In this paper, we suggest the high efficient control method based on general PI control law for a variable speed refrigeration system. In the variable speed refrigeration system, the capacity and the superheat are mainly controlled by an inverter and an electronic expansion valve, respectively, for saving energy and improving coefficient of performance. Thus, we proposed a decoupling model to eliminate the interfering loop between the capacity and superheat at first. Next, we designed PI controller to control the capacity and superheat independently and simultaneously. Finally, the control performance was investigated through some experiments. The experimental results showed that the proposed PI controller based on the decoupling model can obtain good control performance under the various control references and thermal load.

In this paper, we suggest PI control with the Smith predictive controller to improve transient response of a variable speed refrigeration system (VSRS). As the refrigeration system has long dead time inherently, it is difficult to get fast responses of super-heat and reference temperature. We incorporated the Smith predictive controller into PI to compensate the effect of the long dead time of the system. At first, we introduced the decoupling model of the system to control capacity and superheat simultaneously and independently. Next, we designed the predictive controller of the superheat based on PI control law. Finally, the control performance by the proposed method was investigated through some numerical simulations and experiments. The results of the simulations and experiments showed that the proposed PI control with the predictive controller could obtain acceptable transient behaviour for the system.

The diesel Auxiliary Power Unit (APU) for vehicle applications is a complex nonlinear system. For the purpose of this paper presents a dynamic average model of the whole system in an entirely physical way, which accounts for the non-ideal behavior of the diode rectifier, the nonlinear phenomena of generator-rectifier set in an elegant way, and also the dynamics of the dc load and diesel engine. Simulation results show the accuracy of the model. Based on the average model, a simple PI control scheme is proposed for the multivariable system, which includes the steps of model linearization, separate PI controller design with robust tuning rules, stability verification of the overall system by considering it as an uncertain one. Finally it is tested on a detailed switching model and good performances are shown for both set-point following and disturbance rejection.

A novel flatness sensing system which is called the Flatness Sensing Inter-stand Looper(FlatSIL) system is suggested and a self-tuning PI control system using the FlatSIL is designed for improving the flatness of hot strip in finishing mill processes. The FlatSIL system measures the tension along the direction of the strip width by using segmented rolls, and the tension profile is approximated through the tension of each segmented roll. The flatness control system is operated by using the tension profile. The proposed flatness control system as far as the tension profile-measuring device works for the full strip length during the strip rolling in finishing mills. The generalized minimum variance self-tuning (GMV S-T) PI control method is applied to control the flatness of hot strip which has a design parameter as weighting factor for updating the PI gains. Optimizing the design parameter in the GMV S-T PI controller, the Robbins-Monro algorithm is used. It is shown by the computer simulation and experiment that the proposed GMV S-T PI flatness control system has better performance than the fixed PI flatness control system.

Cascaded H-Bridge rectifier (CHBR) is a more attractive solution in traction application for its transformerless structure. Because of the currents of different cells are exactly the same one, it is a challenge job to regulate the voltages of cells with only one current controller. In this paper, a PI-based control scheme is presented to deal with the voltages balance issue in CHBR. To satisfy the demand of rectifier such as unity power factor and regulated output DC voltages, the proposed control scheme consists of two parts. One is for shaping the grid current waveform and regulating the sum of DC-link voltages of all the cells; the other one is for balancing DC-link voltages. The latter is more concerned in this paper and is discussed in detail especially. Simulations and experiments are carried on. The results verified the feasibility and effectiveness of the proposed scheme.

Many real world control systems usually track several control objectives, simultaneously. At the moment, it is desirable to meet all specified goals using the controllers with simple structures like as proportional-integral (PI) and proportional-integral-derivative (PID) which are very useful in industry applications. Since in practice, these controllers are commonly tuned based on classical or trial-and-error approaches, they are incapable of obtaining good dynamical performance to capture all design objectives and specifications. This paper addresses a new method to bridge the gap between the power of optimal multiobjective control and PI/PID industrial controls. First the PI/PID control problem is reduced to a static output feedback control synthesis through the mixed $H_2/H_{\infty}$ control technique, and then the control parameters are easily carried out using an iterative linear matrix inequalities (ILMI) algorithm. Numerical examples on load-frequency control (LFC) and power system stabilizer (PSS) designs are given to illustrate the proposed methodology. The results are compared with genetic algorithm (GA) based multiobjective control and LMI based full order mixed $H_2/H_{\infty}$ control designs.

본 연구는 DQ좌표계를 이용한 다이오드 브리지형 단상 PFC의 고성능 전류제어에 관한 논문이다. 단상전원에서는 일반적인 DQ좌표계를 구성할 수 없기 때문에 3상전원과 같은 동기좌표계상의 전류제어계를 구성하기가 어렵다. 특히 다이오드 브리지형 PFC의 경우 입력전압이 정현파의 절대값 형태로 나타나므로 이상적인 전류제어가 매우 힘들다. 본 연구에서는 위상각이 0~180도만 유지하는 가상 DQ좌표계를 도입하여 동기좌표계상의 전류제어계를 구현함으로써 전류제어성능을 크게 증가시키고 역률을 1로 유지하는 알고리즘을 제안한다.

This paper presents an extended integral control with the PI controller by introducing the delay and decaying factors. The extended integral control scheme is developed by substituting the proportional convolution integral control for the PI(Proportional Integral) control. So far, the integral part of PI controller produces a signal that is proportional to the time integral of the input signal to the controller. The steady-state operation points are affected forever by errors in the past due to the input signal containing the information of the error in the past. These phenomena may cause some disturbances for other control purposes related to the given PI control. Introduction of forgetting factors to the error in the past can resolve the disturbance problems. Various forgetting factors are developed using the delay elements, the decaying factors, and the combination of the delay and decaying factors. The proposed various extended integral control schemes can be applicable to the corresponding PI control designs in which the error in the past may badly affect the current steady-state operation points and may cause some disturbances for other control purposes.

This paper proposes the used of genetic algorithm for optimizing PI controller and describes the dynamic modeling simulation for the permanent magnet synchronous motor driven by simplified vector control with the aid of MATLAB-Simulink environment. Furthermore, three kinds of error criterion minimization, integral absolute error, integral square error, and integral time absolute error, are used as objective function in the genetic algorithm. The modeling procedures and simulation results are described and presented in this paper. Computer simulation results indicate that the genetic algorithm was able to optimize the PI controller and gives good control performance of the system. Moreover, simplified vector control on permanent magnet synchronous motor does not need to regulate the direct axis component current. This makes simplified vector control of the permanent magnet synchronous motor very useful for some special applications that need simple control structure and low cost performance.