Fauzi Ahmad

Modelling and PID control of antilock braking system with wheel slip reduction to improve braking performance

This paper presents the development of a PID controller for an Antilock Braking System (ABS) using vehicle longitudinal model. A Five Degree of Freedom (5-DOF) vehicle longitudinal dynamic model was derived and integrated with an analytical tyre dynamics, the Magic Tyre model. Several transient handling tests are performed such as sudden acceleration and sudden braking test to validate the vehicle model. The model is used as a plant to develop an antilock braking system to control longitudinal slip and reduce the stopping distance. A hydraulic brake model was developed as the brake actuator to produce brake torque. A conventional PID controller has been implemented to deal with the strong nonlinearity in the design of ABS controller. The proposed ABS control structure is shown able to significantly reduce stopping distance and control the longitudinal slip during heavy braking.

Gain Scheduling PID Control with Pitch Moment Rejection for Reducing Vehicle Dive and Squat

This paper presents a derivation of a full vehicle model to study vehicle dynamics behaviour in longitudinal direction. The full vehicle model is then validated using an instrumented experimental vehicle based on the driver input from brake and throttle pedals. Two tests are performed for the purpose of model validation, namely, sudden braking and sudden acceleration test. The results of the validation show that the behaviours of the model closely follow the behaviour of a real vehicle. An active suspension control system is then developed on the validated full vehicle model to reduce unwanted vehicle motions during braking and throttling manoeuvres. The proposed controller structure for the active suspension system is gain scheduling PID control with pitch moment rejection loop. The results show that the proposed control structure is able to significantly improve the dynamic performance of the vehicle during sudden braking and sudden acceleration under various conditions.

Modelling, validation and adaptive PID control with pitch moment rejection of active suspension system for reducing unwanted vehicle motion in longitudinal direction

This paper provides a detailed derivation of a full vehicle model, which may be used to simulate the behaviour of a vehicle in longitudinal direction. The 14 degrees of freedom (14-DOF) vehicle model is integrated with an analytical tyre dynamics using Calspan tyre model. The full vehicle model was validated experimentally with an instrumented experimental vehicle based on the driver input from brake or throttle pedals. Several transient handling tests were performed, namely sudden acceleration and sudden braking test. Comparisons of the experimental result and model response with sudden braking and throttling imposed motion are made. The results of model validation show that the trends between simulation results and experimental data are almost similar with acceptable error. An adaptive PID control strategy was implemented on the validated full vehicle model to reduce unwanted vehicle motions in longitudinal direction during sudden braking and throttling manoeuvre. The results show that the proposed control structure is able to significantly improve the dynamic performance of the vehicle during sudden braking and sudden acceleration under various conditions.

Model-in-the-loop simulation of gap and torque tracking control using electronic wedge brake actuator

This paper presents gap and torque tracking controls of a new braking system for Brake-by-Wire (BBW) using a wedging mechanism. A validation technique known as Model-in-the-Loop Simulation (MILS) is proposed to evaluate the effectiveness of EWB actuator and model. MILS is divided into two types of techniques, which are Hardware-in-the-Loop Simulation (HILS) using real EWB actuator and Software-in-the-Loop Simulation (SILS) using Gaussian cumulative distribution technique. A brake test rig is developed for HILS using EWB actuator, Electronic Control Unit, National Instrument board, xPC Host and Target PC. Meanwhile, mathematical equations are developed for SILS using Matlab Simulink. Both techniques are used to evaluate the performance of EWB actuator and EWBs mathematical model in controlling the gap and torque using various inputs. The results show that the responses from the actuator and EWB model closely followed the desired trajectories, indicating that EWB is capable to be used for vehicle active braking.

Design and clamping force modelling of electronic wedge brake system for automotive application

Most automotive vehicles utilise hydraulic system for actuating braking mechanism producing brake torque to wheels. Besides being disadvantageous on weight, space and system, hydraulic brake requires high energy to flow brake fluid for pushing piston. Leakage and vaporisation of hydraulic fluid are main problems that degrade braking performance of hydraulic brake system. A new design of electronic wedge brake system is presented to replace and to overcome the shortcomings of hydraulic brake system. The proposed electronic wedge brake system consists of piston, wedge mechanism, worm gear and an electric motor. Rotational motion of worm gear driven by electric motor will activate wedge mechanism causing piston to displace linearly. Displacement of piston will generate clamping force between pads and disk thus producing brake torque. The proposed electronic wedge brake system is developed and its behaviour is investigated using brake test rig. The proposed electronic wedge brake system is modelled mathematically. Parameters for model were obtained experimentally. The model was validated by comparing response of the model with experimental rig.

Transmission of Microwave Signal through Metal-Oxide Thin Film of Energy Saving Glass Using Different Shape of Frequency Selective Structure

Metal oxide thin films are widely used for energy saving glass coating. This coating has the ability of blocking the infrared signal while being transparent to other visible part of the spectrum. However, there is one critical disadvantage of this metal oxide coating which it attenuates useful radio frequency and microwave signal such as GSM mobile signal, personal communication, GPS signal through them. These important microwave signals are fall within the range of 800 MHz to 2200 MHz. Frequency selective structure has been applied to solve the attenuation of microwave signal. With the adding of frequency selective structure, it can bring huge improvement of the transmission loss through it. Computer simulation using CST software is used to investigate the transmission loss through the metal oxide coated glass. The frequency selective structure will be etched out from the metallic oxide coated on the glass. Results showed that different shape of the structure will have different peak transmission loss through the glass. When cross dipole and circle shape been simulated using CST software, it can clearly see that the transmission lost and peak frequency had changed drastically. Then, triangle and pentagon shape also have different transmission through it. In addition, conductivity and electrical properties of coated metal oxide thin film is also very important. The transmission through the different ohmic sheet resistance of metal oxide thin film was also investigated. The sheet resistance value was obtained from the reported experimental results. Simulated results showed that full width half maximum, maximum transmission loss and peak frequency loss was very much dependent on the metal oxide sheet resistance. Therefore, the control of the thickness and oxygen content in metal oxide thin film are very much important to optimize the transmission loss through it for energy saving glass applications.

Active roll control suspension system for improving dynamics performance of passenger vehicle

This paper presents the roll moment rejection control of pneumatically actuated active roll control (ARC) suspension system for a passenger vehicle. The controller consists of the two controller loops namely inner loop controller to cancel out the unwanted weight transfer and outer loop controller to suppress both body vertical displacement and body roll angle using Fuzzy Logic Control. Two types of vehicle dynamics test are performed by simulation for the purposed control structure namely step steer test and double lane change test. The results of simulation show that the ARC system is able to significantly improve the dynamic performance of the vehicle compared with the passive system such as body roll angle, body roll rate, body vertical acceleration and body vertical displacement.

Pid Controller with Roll Moment Rejection for Pneumatically Actuated Active Roll Control (ARC) Suspension System

This chapter presents a successful implementation of PID controller for a pneumatically actuated active roll control suspension system in both simulation and experimental studies. For the simulation model, a full vehicle model which consists of ride, handling and tire subsystems to study vehicle dynamics behavior in lateral direction is derived. The full vehicle model is then validated experimentally using an instrumented experimental vehicle based on the driver input from the steering wheel. Two types of vehicle dynamics test are performed for the purpose of model validation namely step steer test and double lane change test. The results of model validation show that the behaviors of the model closely follow the behavior of a real vehicle with acceptable error. An active roll control (ARC) suspension system is then developed on the validated full vehicle model to reduce unwanted vehicle motions during cornering maneuvers such as body roll angle, body roll rate, vertical acceleration of the body and body heave. The proposed controller structure for the ARC system is PID control with roll moment rejection loop. The ARC system is then implemented on an instrumented experimental vehicle in which four units of pneumatic actuators are installed in parallel arrangement with the passive suspension system. The 1

Study on the potential application of electronic wedge brake for vehicle brake system

This paper presents a study of the potential application of an electronic wedge brake for vehicle brake system using human-in-the-loop simulation. Simulation was made in MATLAB Simulink software which interfaces an imaginary vehicle with a real time input from a human, such as throttle and brake input. The imaginary vehicle model that is used is a vehicle dynamic model that has been validated experimentally using an instrumented experimental vehicle. A validated electronic wedge brake actuator model was then used as the brake actuator model where a suitable control strategy, namely proportional-integral-derivative and proportional-integral controllers, was utilised as the force and gapping control respectively. To verify the effectiveness of the proposed actuator in a vehicle, the simulation results are compared with the results of human-in-the-loop simulation of a vehicle using a conventional hydraulic brake and the response of the experimental vehicle using the same dynamic test, namely the sudden braking test. The simulation results show that the proposed simulation method and actuator with appropriate controller strategy have similar behaviour to a hydraulic brake in terms of its capability to produce the desired braking force to reduce the speed and halt the vehicle. The outcomes from this study can be considered in design optimisation and implementation in a real vehicle.

Optimization of Transmission Lost for Energy Saving Glass with Different Sheet Resistance Values

Recently, energy saving glass is commonly applied in the modern engineered building. This is due to its advantages of keeping the heat inside the building in winter while rejecting the heat when in summer. The typical energy saving glass is made by applying a very thin metallic oxide such as silver oxide or tin oxide on one side of the float glass. But at the same time, it has the disadvantages of attenuates useful microwave frequencies that ranging from 0.8 2.2 GHz. The examples of the microwave frequency at this range are GSM mobile signal, GPS and personal communication. Frequency selective surface (FSS) has been introduced to overcome this drawback of energy saving glass. In this study, the transmission of the microwave signal is observed through the simulation using Computer Simulation Technology Microwave Studio. Bandpass frequency selective surface of cross dipole shape is used for the simulation. In the simulation, conductivity and electrical properties of glass and metal oxide thin film are important. The microwave transmission was evaluated at various sheet resistance of metal oxide thin film. The results show that the minimum transmission lost increased with the ohmic resistance increased. On the other hand, the peak frequency at various sheet resistance shows constant value at around 1.25-1.30 GHz. The full width half maximum of the microwave transmission increases with the sheet resistance value. The results suggest that FSS structured metal oxide thin film with lowest sheet resistance transmits more signal in the range for GSM phone signal.