Abstract: Due to the great power of hydraulic system actuators, the control of electro-hydraulic actuators has been an important and ever developing point of research in the field of humanoid robots. But due to the non-linearities of the hydraulic systems, It is very difficult to implement either motion or force controllers on the hydraulic actuators experimentally before the mechanism is modeled and simulated. This is due safety reasons and complex control issues. So, taking into account the humanoid robot HYDROïD, this paper presents the design of PID position and force control algorithms, tested on an electro-hydraulic servo actuator. This actuator is one of the actuators present on the robotic arm of HYDROïD. The virtual model of the system is built through co-simulation between ADAMS [1] and EASY5 [2] software. The output results were later validated using hardware implementation.

Abstract: In an attempt to find out quality of imported and manufactured brake sliding-parts, the present research is adopted on practical situations, and the car SAIPA 131 was selected. As a device to accomplish the work tests, a full-scale brake rig was built. Temperature allocation of brake pad frictional-lining is obtained over a period of drag braking tests. Six locations in radial and peripheral directions are selected to measure nodal temperatures. Also, average frictional-coefficient has measured through a small strain gauge system. These mentioned factors (temperature and frictional coefficient) have a great effect on the braking-performance and that why they are addressed. Results showed different behavior over the increase of brake pressure and velocity where the curve shape and maximum temperature are varied. Brake period, temperature oscillating and the variation in nodal temperature increased with pressure. Also, on the same pad, it has been shown that the increase in number of braking application with the same conditions caused temperature to decrease.

Abstract: The characteristics of a natural vacuum solar desalination unit is studied. A prototype of natural vacuum solar desalination consists of solar collector, evaporator and condenser as the main components has been designed and fabricated. The collected heat in the 3 m2 solar collector is transferred into the evaporator using a transfer fluid system flowed by a pump powered by solar cell. The objective is to explore the characteristics of fresh water production of the natural vacuum solar desalination. The prototype is tested by exposing the unit to solar irradiance on a top roof of a building in Medan city of Indonesia. The experiments are carried out from 8.00 WIB to 16.00 WIB local time. The results show that the prototype can produce fresh water from 0.87 liters to 1.47 liters per day. The characteristics of fresh water production rate can be divided into five different periods. The first period is initial period or the period without fresh water production. The second period is first rising rate, where the main driving force for desalination is solar irradiation. The third period is constant production rate. The fourth period is second rising production rate, where the main driving force for desalination is ambient temperature. And the final period is falling production rate. The thermal efficiency of the system is relatively low which varies between 6.95% and 8.69%. Those facts suggest that the present prototype is far from efficient. Thus, several modifications are needed to improve the performance of the system.

Abstract: In this work, an experimental and numerical investigation was designed for recover the waste heat from the air conditioning system. The model includes a vertical thermal glass capsule with diameter of 60 mm and length of 300 mm of glass thickness 1.5 mm. The capsule containing paraffin wax as a phase change material (PCM) with 9mm diameter copper tube with U-shaped for passing water flow through it as a discharging heat transfer fluid. The study focusses on the enhancement heat transfer by adding Alumina nanoparticles (AL2O3) with volume fractions (0.5%, 1%, 2% and 3%). The results indicate the effects of AL2O3 decreases melting rate time a proximately 7,15,11,9% besides decreases solidification rate time approximately 4,8,6,5% respectively as compared to pure paraffin. Also, the effect of adding a pair of copper tubes inside the paraffin wax was tested during melting and solidification process.

Abstract: The presence of disturbances during flight may destabilize the quadrotor control and could compromise the designated mission. This paper proposes an improved quadrotor flight control in the presence of wind disturbances where the performance will be more robust in many flight conditions. This is achieved by integrating artificial intelligence (AI) technique with disturbance observer-based feedback linearization to improve the disturbance approximation and compensation. The AI technique via radial basis function neural network (RBFNN) is implemented to compensate the bounded estimation error produced by the disturbance observer. The weights of the neural network are tuned online with no prior training required. Simulation results demonstrate the effectiveness and feasibility of the proposed technique.

Abstract: The photovoltaic is the technique used widely in the electricity production in applications of the renewable energy sources, and it is important to have a capacity to evaluate the performance of the systems installed. In this work, a model of simulation to predict the performance of technology system polycrystalline, connected to the grid and working in the weather conditions of the installation location in the city of Meknes (Morocco). The model of the photovoltaic panel proposed gives us a view of the panel parameters as well to validate with the experimental data of a grid connected photovoltaic system of 2 KWp installed at the roof High School of Technology in Meknes under the project “propre.ma”.

Abstract: many studies about modelling and control of UAVs have been demonstrated in different ways. This paper presents a simple empirical method for modelling and controlling the quadcopter. The study was done by measuring and preparing all the parameters of the model using a custom rig, followed by the simulation to observe the behavior of the vehicle and the performance of the controller (PID.) Then it was tested for flying outdoors. The study discusses model parameters identification, various tuning methods, Inertial Measurement Unit (IMU) sensors, position control, introduction of different types of disturbances, and the integration between Simulink and Arduino. As a result of this synergistic approach, the objectives of the design were accomplished for real maneuvering situations, on the laboratory test bench and outdoor environments. In brief, this specific quadcopter is qualified to be implemented for outdoor applications.

Abstract: Wire electrical discharge turning (WEDT) allows success in the machining of advanced materials, particularly for the cylindrical shape components used in the metrology, medical and aerospace field. Using WEDT technology, the micro dimension of geometrical features can be machined without constraints on difficult-to-machine electrically conductive materials. The high precision with large aspect ratio machining capability make WEDT valuable. The correct machining parameter selection is the most important aspect to take into consideration when machining by WEDT. Therefore, the purpose of this study was to rank, determine and optimise the machining parameters that affect the material removal rate (MRR) in WEDT process. As WEDT has as much as eleven control parameters in this study, representing a large number of machining, the Taguchi L-12 orthogonal array was used to obtain the required data with a minimum number of experiments. By using similar experimental data, the regression equation was developed to represent as fitness function for optimisation by genetic algorithm (GA). It was found that by selecting the fast feed of workpiece to machining zone, the faster material was removed and moreover, it dominated other machining parameters. The optimised parameters yield 1.398 mm³/min as the maximum value predicted for MRR recommended by GA.

Abstract: The delamination is defect which leads to reduce the mechanical properties of composite structure, as a results different mechanical behavior of the structure can be altered. Since the buckling behavior is one the most important mechanical behavior of composite structure for many engineering application. Then, it is necessary to investigate the effect of various delamination parameters, such as size (dimensions of delamination) and position (at x, y, and z-directions) on the buckling characterization of composite plate structure. The present study includes evaluating of the critical buckling load by using two techniques. First, experimental techniques, by testing the plates manufactured samples (including delamination) with buckling test, As well as, evaluating the mechanical properties of materials which are necessary to be used as input data for numerical techniques. Second, numerical technique by using Ansys program as an application of finite element method. A comparison between the results of the two methods are made to show the validity of these techniques. A model of composite plate combined from glass woven reinforcement fiber and epoxy resin materials with six layers is fabricated and tested, the plate is clamped supported from two edge and free supported from other edges. The comparison between the results shows an acceptable agreement between the experimental and numerical analysis where the error is not exceed about (10.7%). Finally, the results show that the delamination leads to reduce the buckling strength of composite plate structure, with the increasing of the delamination size and as the location is approached the point at which the maximum bending moment occurs.

Abstract: An effective anti-windup scheme plays an important role to ensure the reliability and robustness of time critical steer-by-wire (SbW) system. This paper addresses a new SbW model formulation with the integration of anti-windup scheme approach which is designed to ensure stability of SbW system in the presence of time delays and actuator saturation. A steering system model is developed as the first step to pave the way for the development of the anti-windup scheme. The measurement of road wheel angle is used as a feedback in the designing process of the anti-windup compensator. Next, coupled with controller used in the SbW systems, an anti-windup compensator designs begin with the formation of augmented state matrix, where the stability condition is expressed in the form of linear matrix inequalities (LMIs). The adaptation of the vector valued of dead zone nonlinearity in the LMI design is introduced to reduce the unwanted saturation effect at the control input. The compensator parameters are obtained by solving a set of LMI conditions which is developed based on Lyapunov-Krasovskii candidate function. The efficacy of the proposed method is verified on the SbW system simulated on Matlab/Simulink. The simulation run under various time delays conditions with saturated actuator demonstrated that the proposed method results in good system performance and fulfill control system requirement.

Abstract: Cascaded Thermal Energy Storage (CTES), a term that refers to a thermal energy storage system with multiple Phase Chance Materials (PCMs), has been enhanced by using metal foam. The present paper includes an experimental and numerical investigation for discharging process at different Heat Transfer Fluid (HTF) velocities, for three systems: single PCM; CTES, and CTES with metal foam at different porosities. The PCMs used are paraffin waxes with different melting temperatures. The main findings are: metal foam make the temperature distribution of PCM and the solidification process more regular and reduces the solidification time; the decreasing metal foam porosity leads to increased improvement; metal foam improves the total thermal power and average Nusselt number of HTF in CTES by rate of about (16.82% to 35.23%) and (24.25% to 42.03%) respectively, and there is a good agreement between the experimental and numerical results.

Abstract: Sit to stand (STS) motion has recently been given an intensive attention by both biomechanical and robotics researchers. STS motion determinants are factors that affect the performance of the STS motion. Determinants differ with their affect based on how they are related to the STS motion, such as chair-related, subject-related and motion-settings-related. Humans who face issues with performing an STS motion find difficulties to perform the motion successfully when they are subjected to wear a prosthetic device. Torque produced by the motors used to help the patients performing a STS motion is one of the parameters that can affect how successful the motion can be performed. Moreover, hip joint’s initial position is one of the parameters that affects the STS motion performed with the aid of the prosthetic devices. It was hypothesized that the relationship between the hip and knee joints initial position (θ_hip,θ_knee) and their torque (τ_hip,τ_knee) is not linear. In this project, the objectives were to investigate the effect of changing the hip initial position on the torque required by each joint to successfully perform the STS motion in both experimental and simulation environment. Experiments were conducted to ensure the validity of the hypothesis. The experiments were designed in a way to imitate the human body measurements and the motion was planned in the same way humans do. The torque produced by each joint was fitted and a 2nd degree polynomial relationship was created to predict the maximum and minimum torque based on the hip’ initial position. The results show that the goodness of the line fitting is close to 1, with a confidence level of 95%, ranging from 0.8672 to 0.9799.

Abstract: This paper presents the development of a self-adaptive trajectory generation system based on negotiation principle. In this paper, the problem is in specifying a trajectory when conflict occur in a system under controlled condition where there is a robot and human that initially are required to perform specific task but due to some limitation, human unable to perform the task perfectly. Here, robot are required to deals with the partner to produce trajectory that satisfy both party by compromising its initial trajectory. Therefore, this paper presents a self-adaptive trajectory generation system based on negotiation principle. The fourth negotiation principle which insist on using objective criteria are implemented in the algorithm. The performance of robot is presents in terms of negotiation outcomes. The results shows that the robotic system able to perform negotiation outcomes with high utility scores which is 0.73. It is hypothesized that the higher utility of robot indicates the partner accept the negotiated value. Therefore, this method is consider as a valuable method that can solve the conflict that occurs during motion generation that cause due to individual limitation.