Mustefa Jibril

The main objective of the suspension of a vehicle is to maximize the contact between the vehicle tires and the road surface, provide steering stability and provide safe vehicle control in all conditions, evenly support the weight of the vehicle, transfer the loads to springs, and guaranteeing the comfort of the driver by absorbing and dampening shock. This paper discusses the kinematic design of a double a-arm Suspension system for ABAY Vehicle. The hardpoint's location can be determined using this procedure to simulate motion in any kinematic simulation software. Here, Optimum Kinematics is used as kinematic simulation software. The method illustrated deals with the basics of Kinematics which helps to predict the characteristics of the suspension even before simulating it in the kinematic simulation software.

Suspension system is used to fulfil the criteria of ride comfort and road handling. In this paper, a quarter car active & semi-active suspension systems are designed using Matlab/Script software. Comparison of active & semi-active suspension systems are done using robust control theory for the control targets suspension deflection, body acceleration and body travel. H infinity controller is selected to compare the two suspensions using time domain analysis. Finally the simulation result prove the effectiveness of the active suspension system by decreasing the body acceleration & sustaining the suspension deflection and body travel outputs.

This paper offers a short survey of linear systems Proportional-Integral-Observer design. This observer has the capacity to estimate simultaneously the states and unknown inputs which include disturbances or model uncertainties appearing on the system. The design of state and output estimation using PO and state, output and disturbance estimation using PIO is done using Matlab/Simulink successfully. The simulation is done for estimating using PO and PIO and the results proved that estimates the state variables and output correctly when there is no disturbance in the plant and there is a constant steady-state error in estimation after leading a constant disturbance into the plant for both state variables and plant output for the Proportional Observer and there is ability to estimate state variables, disturbance and system output correctly with or without the disturbance in plant for the Proportional Integral Observer.

In this paper an attempt has been made towards the design and evaluation of a solar parabolic trough collector (PTC) system integrated with a conventional oil boiler (COB) to increase the energy utilization effectiveness and reduce the environmental emission of the existing conventional oil boiler in the Kombolcha textile factory, in Ethiopia. The factory uses 8500 ton/annum of heavy fuel oil to generate 26 ton/hour of pressurized hot water at 140C temperature which causes an increase in greenhouse gas emissions, so the solar parabolic trough collector hot water generation system will be an appropriate solution for this application. Based on the available annual solar radiation, estimates of the solar fraction, solar energy unit price and system pay-back period have been carried out. The proposed system has the potential to save 1055.9 ton/year of fuel oil. The unit cost of PTC solar energy is estimated to be 0.0088 $/kWh and the payback period of the plant is five years. Since the unit price of oil energy (0.0424 $/kWh) is much greater than the unit price of solar energy by a substantial margin (0.033 $/kWh) in Ethiopia, therefore the water heating system by a solar parabolic trough collector is a feasible alternative to heating by a conventional oil boiler.

Continuous Stirred Tank Reactor (CSTR) is amajorarea in process, chemical and control engineering. In this paper, PID and MPC controllers are designed for CSTR in order to analyze the output concentration of the system by comparing the two proposed systems using Matlab/Simulink. Comparison have been made using two desired concentration input (Random reference and step) signals with and without input side disturbance (Flow rate error). The simulation result shows that the continuous stirred tank reactor with MPC controller have better response in minimizing the overshoot and tracking the desired concentration for the system without input disturbance and with the effect of the disturbance makes the continuous stirred tank reactor with MPC controller output with small fluctuations and still better than the continuous stirred tank reactor with PID controller. Finally the comparative analysis and simulation results prove the effectiveness of the continuous stirred tank reactor with MPC controller.

In this paper, a Magnetic Levitation (MAGLEV) train is designed with a first degree of freedom electromagnetbased totally system that permits to levitate vertically up and down. Fuzzy logic, PID and MRAS controllers are used to improve the Magnetic Levitation train passenger comfort and road handling. A Matlab Simulink model is used to compare the performance of the three controllers using step input signals. The stability of the Magnetic Levitation train is analyzed using root locus technique. Controller output response for different time period and change of air gap with different time period is analyzed for the three controllers. Finally the comparative simulation and experimental results demonstrate the effectiveness of the presented fuzzy logic controller.

The main target of this paper is to control the speed of DC motor by comparing the actual and the desired speed set point. The DC motor is designed using Fuzzy logic and MPC controllers. The comparison is made between the proposed controllers for the control target speed of the DC motor using square and white noise desired input signals with the help of Matlab/Simulink software. It has been realized that the design based on the fuzzy logic controller track the set pointwith the best steady state and transient system behavior than the design with MPC controller. Finally, the comparative simulation result prove the effectiveness of the DC motor with fuzzy logic controller.

This study aimed to examine the influence it is to study skills and academic‐related stress in the academic performance of the students of the university. A descriptive research project was used. The study was carried out among students of engineering at the University of Dire Dawa. The study involved 400 students of the engineering bachelor's degrees, one hundred and from the second to the 5th year which has been evaluated for the academic stress and to study skills. A random sample is used to select objects for the study of the system. Three tools were used: Tool I: Socio‐demographic Profile Sheet, Tool II: Study Skills Assessment Questionnaire, Tool III: Perceived Stress Scale. The results of this study showed that the students performed well in all the subjects, except for the time‐management method and writing skills. More than two‐thirds of the surveyed students have a low level of stress. Academic stress is higher in senior and female students. There was a negative correlation between the student’s stress and their study skills. Statistically significant relationships were found between academic performance, study skills and the stress level of the students surveyed.

Recently, active suspension system will become important to the vehicle industries because of its advantages in improving road managing and ride comfort. This paper offers the development of mathematical modelling and design of a neural network control approach. The paper will begin with a mathematical model designing primarily based at the parameters of the active suspension system. A nonlinear three by four-way valve-piston hydraulic actuator became advanced which will make the suspension system under the active condition. Then, the model can be analyzed thru MATLAB/Simulink software program. Finally, the NARMA-L2, model reference and predictive controllers are designed for the active suspension system. The results are acquired after designing the simulation of the quarter-car nonlinear active suspension system. From the simulation end result using MATLAB/Simulink, the response of the system might be as compared between the nonlinear active suspension system with NARMA-L2, model reference and predictive controllers. Besides that, the evaluation has been made between the proposed controllers thru the characteristics of the manage objectives suspension deflection, body acceleration and body travel of the active suspension system. . As a conclusion, designing a nonlinear active suspension system with a nonlinear hydraulic actuator for quarter car model has improved the car performance by using a NARMA-L2 controller. The improvements in performance will improve road handling and ride comfort performance of the active suspension system.

In this paper we describe a technical system for DC motor speed control. The speed of DC motor is controlled using Neural Network Based Model Reference and Predictive controllers with the use of Matlab/Simulink. The analysis of the DC motor is done with and without input side Torque disturbance input and the simulation results obtained by comparing the desired and actual speed of the DC motor using random reference and sinusoidal speed inputs for the DC motor with Model Reference and Predictive controllers. The DC motor with Model Reference controller shows almost the actual speed is the same as the desired speed with a good performance than the DC motor with Predictive controller for the system with and without input side disturbance. Finally the comparative simulation result prove the effectiveness of the DC motor with Model Reference controller.

This research was conducted at 15 government schools in Addis Ababa. The objectives of this research are to identify principal style and its effect on academic achievement. The “Leader Behavior Description Questionnaire” (LBDQ) formed by Halpin (1966) was used. Meanwhile Academic achievement was measured using the “School Certificate Examination Results from 2017-2020. A total of 191 teachers and 15 principals from government school in Addis Ababa were randomly chosen. Pearson correlation was used to analyze the data. To support data obtained from questionnaire given 10 teachers were interviewed. The results showed that most of the school leaders adopt a democratic style of leadership. There was a significant correlation between the structure of task-oriented leadership style and students’ performance in the examinations. Correlation analysis also showed that principals practice task- oriented structure and consideration-oriented structure in relation to their work responsibilities. Furthermore, findings also showed that majority of the principals are more likely to practice consideration-oriented leadership style compared to structure-oriented leadership style.

In this study, the design and control of a hydraulic system based tire changer machine have been analyzed and simulated using MATLAB/Simulink Toolbox successfully. The machine have a displacement input which is a leg pedal displacement in order to push the piston of the pump to fed the motor with a pressured hydraulic fluid to rotate the tire with an angular speed to mount and dismount it. Augmentation based H4 and H2 optimal synthesis controllers have been used to improve the performance of the machine. Comparison of the proposed controllers for tracking a reference input speed have been done using two reference inputs (step and random) signals. Finally, the comparative simulation results proved the effectiveness of the proposed tire changer with synthesis controller in improving the settling time and percentage overshoot.

In this paper, a solenoid based linearly movable armature system is designed using robust control theory in order to improve the performance of the system. Reference track method is the best performance analysis for position control systems. Among the robust controllers, H infinity mixedsensitivity and Mixed H 2 /H∞ with Regional Pole Placement Controllers are used to improve the performance of the system. Comparison of the proposed controllers for tracking a reference displacement signals (step and sine wave) and a promising simulation result have been obtained.

In this paper, a 2 DOF industrial robotic arm is designed and simulated for elbow and wrist angle and velocity performance improvement using robust control method. Mixed H 2 /H ∞ synthesis with regional pole placement and H 2 optimal controllers are used to improve the system output. The open loop response of the robot arm shows that the elbow and wrist angles and velocities need some improvement. Comparison of the proposed controllers for an impulse and step input signals have been done and a promising results have been obtained.

Steam turbine generator is an electromechanical system which converts heat energy to electrical energy. In this paper, the modelling, design and analysis of a simple steam turbine generator have done using Matlab/Simulink Toolbox. The open loop system have been analyzed to have an efficiency of 76.92 %. Observer based & linear quadratic regulator (LQR) controllers have been designed to improve the generating voltage. Comparison of this two proposed controllers have been done for increasing the performance improvement to generate a 220 Dc volt. The simulation result shows that the steam turbine generator with observer based controller has a small percentage overshoot with minimum settling time than the steam turbine generator with LQR controller and the open loop system. Finally, the steam turbine generator with observer based controller shows better improvement in performance than the steam turbine generator with LQR controller.

In this paper, modelling designing and simulation of a simple voltage amplidyne system is done using robust control theory. In order to increase the performance of the voltage amplidyne system with H infinity optimal control synthesis and H infinity optimal control synthesis via gamma-iteration controllers are used. The open loop response of the voltage amplidyne system shows that the system can amplify the input 7 times. Comparison of the voltage amplidyne system with H infinity optimal control synthesis and H infinity optimal control synthesis via gamma-iteration controllers to track a desired step input have been done. Finally, the comparative simulation results prove the effectiveness of the proposed voltage amplidyne system with H infinity optimal control synthesis controller in improving the percentage overshoot and the settling time.

In this paper, the performance of inverted pendulum have been Investigated using robust control theory. The robust controllers used in this paper are H∞ Loop Shaping Design Using Glover McFarlane Method and mixed H∞ Loop Shaping Controllers. The mathematical model of Inverted Pendulum, a DC motor, Cart and Cart driving mechanism have been done successfully. Comparison of an inverted pendulum with H∞ Loop Shaping Design Using Glover McFarlane Method and H∞ Loop Shaping Controllers for a control target deviation of an angle from vertical of the inverted pendulum using two input signals (step and impulse). The simulation result shows that the inverted pendulum with mixed H∞ Loop Shaping Controller to have a small rise time, settling time and percentage overshoot in the step response and having a good response in the impulse response too. Finally the inverted pendulum with mixed H∞ Loop Shaping Controller shows the best performance in the overall simulation result.

This study considers the problem of using approximate way for realizing the neural supervisor for nonlinear multivariable systems. The Nonlinear Autoregressive-Moving Average (NARMA) model is an exact transformation of the input-output behavior of finite-dimensional nonlinear discrete time dynamical organization in a hoodlum of the equilibrium state. However, it is not convenient for intention of adaptive control using neural networks due to its nonlinear dependence on the control input. Hence, quite often, approximate technique are used for realizing the neural supervisor to overcome computational complexity. In this study, we introduce two classes of ideal which are approximations to the NARMA model and which are linear in the control input, namely NARMA-L1 and NARMA-L2. The latter fact substantially simplifies both the theoretical breakdown as well as the practical request of the controller. Extensive imitation studies have shown that the neural controller designed using the proposed approximate models perform very well and in dozens situation even better than an approximate controller designed using the exact NARMA Model. In view of their mathematical tractability as well as their fate in simulation studies, a matter is made in this study that such approximate input-output paragon warrants a detailed study in their own right.

Better journey comfort and controllability of automobile are pursued via car industries with the aid of considering using suspension system which plays a very crucial function in handling and ride comfort characteristics. This paper presents the design of an active suspension of quarter automobile system using robust H2 optimal controller and robust μ - synthesis controller with a second order hydraulic actuator. Parametric uncertainties have been additionally considered to model within the system. Numerical simulation become completed to the designed controllers. Results display that during spite of introducing uncertainties, the designed μ - synthesis controller improves ride consolation and road protecting of the automobile while as compared to the H2 optimal controller.

Noise reduction is the major issue in the loudspeaker for the application of the musical instruments and related areas. In this paper, a noise disturbance control of a loudspeaker with optimal and robust controllers has been done successfully. The noise of the loudspeaker has been analyzed by simply track a reference cone displacement with the actual cone displacement. Static output feedback and H infinity optimal loop shaping controllers have been used to compare the actual and reference cone displacements by using a sine wave and random cone displacement signals and a promising results have been analyzed.

This paper offers with the theoretical and computational evaluation of optimal& robust controlproblems, with the goal of providing answers to them with MATLAB simulation.For the robust control,  -synthesis controller and for the optimal control, LQR controller are designed for a quarter car active suspension system to maximize the ride comfort and road handling criteria’s of the vehicle. The proposed controllers are designed using Matlab script program using time domain analysis for the four road disturbances (bump, random sine pavement and white noise) for the control targets suspension deflection, body acceleration and body travel. Finally the simulation result proves the effectiveness of the active suspension system with  -synthesis controller.

Magnetic levitation system is operated primarily based at the principle of magnetic attraction and repulsion to levitate the passengers and the train. However, magnetic levitation trains are rather nonlinear and open loop unstable which makes it hard to govern. In this paper, investigation, design and control of a nonlinear Maglev train based on NARMA-L2, model reference and predictive controllers. The response of the Maglev train with the proposed controllers for the precise role of a Magnetic levitation machine have been as compared for a step input signal. The simulation consequences prove that the Maglev teach system with NARMA-L2 controller suggests the quality performance in adjusting the precise function of the system and the device improves the experience consolation and street managing criteria.

Recent years, active suspension system has been widely used in automobiles to improve the road holding ability and the riding comfort. This study presents a new fuzzy model predictive control for a nonlinear quarter car active suspension system. A nonlinear dynamical model of active suspension is established, where the nonlinear dynamical characteristic of the spring and damper are considered. Based on the proposed fuzzy model predictive control method is presented to stabilize the displacement of the active suspension in the presence of different road profiles. Parameters of the model predictive and fuzzy logic control laws are designed to estimate the (Bump and Sinusoidal)road profile input in the active suspension. At last, the reliability of the fuzzy model predictive control method is evaluated by the MATLAB simulation tool. Simulation result shows that the fuzzy model predictive control method obtained the satisfactory control performance for the active suspension system.

This study investigates the outlet temperature control for the design of steam condenser. The comparison has been made for a step drop in the steam condenser temperature set point using MATLAB/ Simulink environment for the steam condenser with NARMA-L2 using Levenberg-Marquardt algorithm and NARMA-L2 using resilient backpropagation algorithm controllers. The steam condenser with NARMA-L2 using Levenberg-Marquardt algorithm controller presented excellent and superior dynamic performance in response to the temperature drop in settling time. The overall simulation results demonstrated that the steam condenser with NARMA-L2 using Levenberg-Marquardt Algorithm controller can be an efficient alternative to the steam condenser with NARMA-L2 using resilient backpropagation algorithm controller.

To improve road dealing with and passenger consolation of a vehicle, a suspension system is supplied. An active suspension system is taken into consideration better than the passive suspension system. In this paper, an active suspension system of a linear quarter vehicle is designed, that's issue to exclusive disturbances on the road. Since the parametric uncertainty within the spring, the shock absorber and the actuator has been taken into consideration, robust control is used. H∞ and µ-Synthesis controllers of are used to improve using consolation and road dealing with potential of the vehicle, in addition to confirm the sturdy stability and overall performance of the system. In the H∞ design, we designed a driving force for passenger consolation and to preserve the deflection of the suspension small and to reduce the disturbance of the road to the deflection of the suspension. For the µ synthesis system, we designed a controller with hydraulic actuator and uncertainty model. We designed a MATLAB / SIMULINK model for the active suspension system with the H∞ and µ-synthesis controllers we tested the use of 4 road disturbance inputs (bump, random, sinusoidal pavement and slope) for deflection of the suspension, body acceleration and body travel for passive, active suspension with controller and active suspension without controller. Finally, we evaluate the H∞ and µ-synthesis controllers with a Simulink model for suspension deflection, body acceleration and body travel simulation, and the result suggests that both designs offer correct overall performance, however the H∞ controller has superior overall performance as compared to the µ-synthesis controller.

In this study, the performance of inverted pendulum has been Investigated using neural network control theory. The proposed controllers used in this study are NARMA-L2 with Resilient backpropagation and Levenberg Marquardt backpropagation algorithm controllers. The mathematical model of Inverted Pendulum on a Cart driving mechanism have been done successfully. Comparison of an inverted pendulum with NARMA-L2 with Resilient backpropagation and Levenberg Marquardt backpropagation algorithm controllers for a control target deviation of an angle from vertical of the inverted pendulum using two input signals (step and random). The simulation result shows that the inverted pendulum with NARMA-L2 with resilient backpropagation controller to have a small rise time, settling time and percentage overshoot in the step response and having a good response in the random response too. Finally, the inverted pendulum with with NARMA-L2 with resilient backpropagation controller shows the best performance in the overall simulation result.

The current study was conducted to assess the attitude of higher education students. The current study sample consists of 600 students selected from the Dire Dawa University. The Student Attitude Inventory (SAI) was developed using 6 subsidies given to sample subjects for data collection purposes. The researcher used the most widely accepted and widely used mathematical methods to analyze and interpret data including mean, SD and t‐test. The results showed that male students had a better and more positive attitude towards the learning process and its affiliates. In addition, these results also showed that urban students had a better learning environment than in rural areas.