Circle grid fractal plate as a turbulent generator for premixed flame: an overview

This review paper focuses to ascertain a new approach in turbulence generation on the structure of premixed flames and external combustion using a fractal grid pattern. This review paper discusses the relationship between fractal pattern and turbulence flow. Many researchers have explored the fractal pattern as a new concept of turbulence generators, but researchers rarely study fractal turbulence generators on the structure premixed flame. The turbulent flow field characteristics have been studied tand investigated in a premixed combustion application. In terms of turbulence intensity, most researchers used fractal grid that can be tailored so that they can design the characteristic needed in premixed flame. This approach makes it extremely difficult to determine the exact turbulent burning velocity on the velocity fluctuation of the flow. The decision to carry out additional research on the effect circle grid fractal plate as a turbulent generator for premixed flame should depends on the blockage ratio and fractal pattern of the grid. 1

The strengthening of Islamic values on students through the metaphor of accepting death: an Indonesian perception

Death is a sure entity for every human that cannot be avoided in human life. The purpose of this research was to reveal that the usage of metaphor technique called, “The Acceptance of Death” in group counselling can improve Islamic values on Muslim students. This study employed an action research using The Kemmis Model with the stages of planning, action, observation, and reflection. This research implemented group counselling with metaphor technique of accepting death by students. The research subjects were 20 female students of State Islamic University of Sultan Syarif Kasim Riau who lived in the campus dormitory. The selection of the research subjects was done randomly by choosing the female students who were willing to join the group counselling activity. The research results showed that the practice of metaphor technique of “The Acceptance of Death” in the group counselling can strengthen the Islamic values and their characteristics as Muslims. They understand their previous mistakes and are willing to be better for the sake of their life. They have the commitment to become the best students and the best Muslims

Position Tracking Performance for ElectroHydraulic Actuator System with the Presence of Actuator Internal Leakage

Electro-hydraulic actuator (EHA) system is known as one of the highly nonlinear systems due to its parameters uncertainties. Many types of robust controller had been studied and proposed to control the nonlinear EHA system. Different parameters uncertainties test is needed in the procedure to evaluate the controller robustness. In this paper, the effect of the actuator internal leakage to the output actuator displacement is studied. The actuator output displacement is analyzed using Root Mean Square Error (RMSE) by means of giving sinusoidal input reference. The results show that as the actuator internal leakage increases, the RMSE will increase and the actuator will start to vibrate or show damping characteristics

Improved Third Order PID Sliding Mode Controller for Electrohydraulic Actuator Tracking Control

An electrohydraulic actuator (EHA) system is a combination of hydraulic systems and electrical systems which can produce a rapid response, high power-to-weight ratio, and large stiffness. Nevertheless, the EHA system has nonlinear behaviors and modeling uncertainties such as frictions, internal and external leakages, and parametric uncertainties, which lead to significant challenges in controller design for trajectory tracking. Therefore, this paper presents the design of an intelligent adaptive sliding mode proportional integral and derivative (SMCPID) controller, which is the main contribution toward the development of effective control on a third-order model of a double-acting EHA system for trajectory tracking, which significantly reduces chattering under noise disturbance. The sliding mode controller (SMC) is created by utilizing the exponential rule and the Lyapunov theorem to ensure closed-loop stability. The chattering in the SMC controller has been significantly decreased by substituting the modified sigmoid function for the signum function. Particle swarm optimization (PSO) was used to lower the total of absolute errors to adjust the controller. In order to demonstrate the efficacy of the SMCPID controller, the results for trajectory tracking and noise disturbance rejection were compared to those obtained using the proportional integral and derivative (PID), the proportional and derivative (PD), and the sliding mode proportional and derivative (SMCPD) controllers, respectively. In conclusion, the results of the extensive research given have indicated that the SMCPID controller outperforms the PD, PID, and SMCPD controllers in terms of overall performance.

Chattering Analysis of an Optimized Sliding Mode Controller for an Electro-Hydraulic Actuator System

Wear and tear are usually caused by various factors, which reduce the life span of a mechanical part. In the control engineering of an Electrohydraulic actuator system, the wear and tear can be caused by the system or the controller itself. This article examines the chattering effect that occurs during the sliding mode controller (SMC) design, and its effect on the nonlinear electrohydraulic actuator (EHA) system. To examine the chattering phenomenon, signum function is first applied on the switching function of the SMC. Then, parameters of the controller are obtained using single objective particle swarm optimization (PSO) method. These parameters are then applied to the switching function with hyperbolic tangent function. Lastly, the performance of both functions is analysed and compared based on graph and numerical data. From the output data, chattering phenomenon generated on the signum function is greatly eliminated by using hyperbolic tangent function

Optimization of Sliding Mode Control using Particle Swarm Algorithm for an Electro-hydraulic Actuator System

The dynamic parts of electro-hydraulic actuator (EHA) system are widely applied in the industrial field for the process that exposed to the motion control. In order to achieve accurate motion produced by these dynamic parts, an appropriate controller will be needed. However, the EHA system is well known to be nonlinear in nature. A great challenge is carried out in the EHA system modelling and the controller development due to its nonlinear characteristic and system complexity. An appropriate controller with proper controller parameters will be needed in order to maintain or enhance the performance of the utilized controller. This paper presents the optimization on the variables of sliding mode control (SMC) by using Particle Swarm Optimization (PSO) algorithm. The control scheme is established from the derived dynamic equation which stability is proven through Lyapunov theorem. From the obtained simulation results, it can be clearly inferred that the SMC controller variables tuning through PSO algorithm performed better compared with the conventional proportionalintegral-derivative (PID) controller

An ABS control logic based on wheel force measurement

The paper presents an anti-lock braking system (ABS) control logic based on the measurement of the longitudinal forces at the hub bearings. The availability of force information allows to design a logic that does not rely on the estimation of the tyre-road friction coefficient, since it continuously tries to exploit the maximum longitudinal tyre force. The logic is designed by means of computer simulation and then tested on a specific hardware in the loop test bench: the experimental results confirm that measured wheel force can lead to a significant improvement of the ABS performances in terms of stopping distance also in the presence of road with variable friction coefficien

Pemodelan dan Pengaturan Adaptif untuk Sistem Hidrolik Tak Linier

Elektro-hidrolik merupakan jenis aktuator yang kompleks dengan ketidaklinieran yang tinggi dan mengandung unsur ketidakpastian di dalamnya. Oleh karena itu, untuk mendapatkan performa terbaik dari sistem elektro-hidrolik diperlukan pemodelan yang lebih akurat dan sistem pengaturan yang tepat. Tujuan dari penelitian ini adalah melakukan pemodelan sistem secara tak linier dan dilanjutkan dengan perancangan sistem pengaturan tak linier yang robust untuk sistem elektro-hidrolik. Dalam tulisan ini pemodelan dilakukan dengan menggunakan Sistem Identification Toolbox pada Matlab dari sepasang data input-output yang diambil dari sistem sebenarnya. Model dari sistem ditampilkan dalam bentuk tak linier, karena mengakomodasi ketidaklinieran, ketidakpastian dan gangguan dari sistem elektro-idrolik. Sistem pengaturan menggunakan Sliding Mode Control (SMC) yang dikombinasikan dengan pengaturan Fuzzy dalam format Adaptif Sliding Mode Control (ASMC) untuk mengkompensasi perubahan parameter, ketidaklinieran, ketidakpastian dan gangguan pada pengaturan SMC. Stabilitas sistem pengaturan dijamin dengan fungsi Lyapunov. Hasil pemodelan tak linier menunjukkan nilai best-fit sebesar 94.65%. Sementara pengaturan ASMC menghasilkan performa lebih baik dibandingkan dengan pengaturan SMC, hal ini dibuktikan menggunakan metode Sum of Squared Tracking Errors (SSTE) menghasilkan nilai sebesar 0,0121