Shamsul Sarip

Study of Model Predictive Control for Path-Following Autonomous Ground Vehicle Control under Crosswind Effect

We present a comparative study of model predictive control approaches of two-wheel steering, four-wheel steering, and a combination of two-wheel steering with direct yaw moment control manoeuvres for path-following control in autonomous car vehicle dynamics systems. Single-track mode, based on a linearized vehicle and tire model, is used. Based on a given trajectory, we drove the vehicle at low and high forward speeds and on low and high road friction surfaces for a double-lane change scenario in order to follow the desired trajectory as close as possible while rejecting the effects of wind gusts. We compared the controller based on both simple and complex bicycle models without and with the roll vehicle dynamics for different types of model predictive control manoeuvres. The simulation result showed that the model predictive control gave a better performance in terms of robustness for both forward speeds and road surface variation in autonomous path-following control. It also demonstrated that model predictive control is useful to maintain vehicle stability along the desired path and has an ability to eliminate the crosswind effect.

A new concept of multimode magnetorheological brake design

This paper presents a magnetorheological (MR) brake design by using additional squeeze working mode to an existing conventional rotational shear. The MR brake was designed with consideration given to a new concept of braking mechanism with the help of magnetic simulation. Important parameters such as disc brake dimensions, clearance gap and electromagnetic coil configuration were taken into account when constructed the MR brake. Simulation results showed that the magnetic field strength was at best by having the magnetic coil beside the non-magnetic material, which was located at the end of the outer diameter. Meanwhile, the value of magnetic field was greater than when a small squeeze gap was applied. Eventually, the design will provide an opportunity to study and consequently understand on how the MR fluids react to such operating condition in order to be realized in the MR brake.

Enhancing vehicle ride comfort through intelligent based control

The research presented in this paper is carried out to investigate the performance of a suspension systems either an active or passive type. Controllers that are used in this study are proposed fuzzy logic controller and proportional integral derivative controller as a benchmarking comparison. The simulations in this research have been carried out using Simulink of MATLAB. The parameters in the simulation model for the suspension system under study include car body mass, wheel mass, spring and damping elements of shock absorber, and tire. The block model of the suspension system has been designed to represent the equation of motion of the sedan car suspension system. The road disturbance for the active suspension system is modelled in two different ways, namely, unit step input signal and sine wave input signal. The simulation results indicate that fuzzy logic control of an active car suspension system has better performance compared to the passive system.

Simulation Studies of a New Magnetorheological Brake with Difference Gap Size Using Combination of Shear and Squeeze Mode

Magnetorheological (MR) brake contains magnetized particles, which are strong, fast and reversible transform in their rheological properties when applied the magnetic field. There are a few types of modes that have been working on in the fluid such as the shear mode, flow mode, squeeze mode and recently a new mode called the magnetic gradient pinch mode. Commonly, shear modes have been widely investigated and used in MR brakes. Nevertheless, limited focus has been given to the combination of shear and squeeze mode due to the design consideration in MR brake. This paper focuses on the design of MR brake with a difference of fluid gap rather than a single gap in one device by using both modes. In this work, a few design criteria are considered to select the basic automotive MR brake configuration such as material selection, MR fluid selection, working surface area, applied current density, and wire size. Then, a Finite Element Method in 2D simulation is performed to analyse the resulting magnetic circuit within the MR brake configuration. Moreover, the simulated results of the magnetic flux density in the MR fluid are used to predict the torque produced by the combination of shear and squeeze modes. It can be concluded that, the finite element simulation predictions show a good correlation between effect of the current and fluid gap.

Enhancing of nominal characteristic trajectory following control for motion systems#br#

The goal of this paper is to enhance a practical nominal characteristic trajectory following (NCTF) controller that is specifically designed for two-mass point-to-point positioning systems. A nominal characteristics trajectory contained in the NCTF controller acts as movement/motion reference and a compensator is utilized to force the object to detect and follow the reference/desired trajectory. The object must follow and track closely and should be as fast as possible. The NCTF controller is designed with two different intelligent based compensator approaches which are fuzzy logic and extended minimal resource allocation network. The proposed controller which is NCTF are compared with the conventional proportional integral compensator. Then the results of simulation are discussed for the positioning performances. The inertia variations due to the effect of the design parameters are also assessed to see the robustness of controllers. The results show that the NCTF control method designed from an intelligent based compensator has a better positioning performance in terms of percentage of overshoot, settling time, and steady state error than the classical based compensator.

Mechanical behavior of Kenaf/Epoxy corrugated sandwich structures

This study presents the response of kenaf/epoxy corrugated sandwich structure during quasi-static test. Force-displacements curves have been deducted to determine the deformation pattern and collapse behavior of the structure. Kenaf/epoxy sandwich structures skins fabricated by using hand layup technique and the corrugated core were moulded by using steel mould. Different thicknesses of corrugated core web with two sizes of kenaf fibers were used. The corrugated core is then bonded with the skins by using poly-epoxy resin and has been cut into different number of cells. The specimens then tested under tensile and compression at different constant speeds until the specimens fully crushed. Tensile tests data showed the structure can be considered brittle when it breaking point strain, e less than 0.025. In compression test, the specimens fail due to dominated by stress concentration that initiated by prior cracks. Also, the specimens with more number of cells and thicker core web have higher strength and the ability to absorb higher energy.

Energy management strategies at emergency department block C Hospital Sungai Buloh, Malaysia

Energy is an important element in human daily life. In Malaysia, about 80% of electrical energy produced from burning fuels that will cause of carbon dioxide emission to atmosphere. The effect could be reduced with less energy consumption. This project focuses on energy management strategies for energy saving that can be done on the HVAC system, air-cond, lighting and office equipment in Emergency Department, Block C Hospital Sungai Buloh. The annual profit, total cost and payment period for each research method are also studied. To implement for all major system must be link to chapter by Buiding Automation System. Major studies for this topic is to implement energy saving, calculate energy comsumption, power, area specific room, return of investment, analysis for daily cost for used, total for kWh for monthly usage.

Selection of Materials in Designing Magnetorheological Brake

The braking system is among the most significant active safety systems in a vehicle application for preventing injuries and property damage. Whether for light or heavy vehicles, brakes are no longer a small issue whereas it becomes a crucial problem to maintain the safety and to avoid the unpredictable cases especially on the road. Advanced technology in automotive industry has produced a new coming design of Magnetorheological (MR) brake which a field change is triggered off by changing the current in the coils exciting the magnetic field. MR fluid is one of the members of smart material which applicable usage to achieve the standard of rotary high speed similar as the existing brake disc in hydraulic system. A new MR brake disc was proposed using the squeeze mode rather than only conventional mode at the upper and lower rotating rotor. Parameters that have been considered are the types of MR fluid, selection of magnetic material, non-magnetic material and coil configurations. Then a finite elements analysis was performed to analyse the result of magnetic circuit and magnetic field strength within the MR brake configuration. MRF-140CG has been selected to represent the fluid to enhance the maximum magnetic flux density. The results showed that AISI 1020 and Stainless Steel 316 meet the requirement of material selection of magnetic and non-magnetic. Indirectly, yield stress has been significant increase when the magnetic field strength rises at certain value. Therefore, intention on design innovation of MR brake is useful to efficient control by upgrading function of those parameters which has been presented.

Analysis of the Transient Thermomechanical Behaviour of a Lightweight Brake Disc for a Regenerative Braking System

Regenerative braking would extend the working range of an EV or HV provided that any extra energy consumption from increased vehicle mass and system losses did not outweigh the saving from energy recuperation, also reduce duty levels on the brakes themselves, giving advantages including extended brake rotor and friction material life, but more importantly reduced brake mass, minimise brake pad wear. The objective of this research is to define thermal performance on lightweight disc brake models. Thermal performance was a key factor which was studied using the 3D model in FEA simulations. Ultimately a design method for lightweight brakes suitable for use on any car-sized hybrid vehicle was used from previous analysis. The design requirement, including reducing the thickness, would affect the temperature distribution and increase stress at the critical area. Based on the relationship obtained between rotor weight, thickness, undercut effect and offset between hat and friction ring, criteria have been established for designing lightweight brake discs in a vehicle with regenerative braking.