Noor Hafizah Amer

Modelling and Control Strategies in Path Tracking Control for Autonomous Ground Vehicles: A Review of State of the Art and Challenges

Autonomous vehicle field of study has seen considerable researches within three decades. In the last decade particularly, interests in this field has undergone tremendous improvement. One of the main aspects in autonomous vehicle is the path tracking control, focusing on the vehicle control in lateral and longitudinal direction in order to follow a specified path or trajectory. In this paper, path tracking control is reviewed in terms of the basic vehicle model usually used; the control strategies usually employed in path tracking control, and the performance criteria used to evaluate the controller’s performance. Vehicle model is categorised into several types depending on its linearity and the type of behaviour it simulates, while path tracking control is categorised depending on its approach. This paper provides critical review of each of these aspects in terms of its usage and disadvantages/advantages. Each aspect is summarised for better overall understanding. Based on the critical reviews, main challenges in the field of path tracking control is identified and future research direction is proposed. Several promising advancement is proposed with the main prospect is focused on adaptive geometric controller developed on a nonlinear vehicle model and tested with hardware-in-the-loop (HIL). It is hoped that this review can be treated as preliminary insight into the choice of controllers in path tracking control development for an autonomous ground vehicle.

A review on control strategies for passenger car intelligent suspension system

The main function of a suspension system is to reduce/isolate vibration caused by road irregularities to improve comfort, reliability and road holding of the vehicle. In this paper, various control aspects in controllable suspension are reviewed focusing on suspension performance criteria, control strategies and control methodologies. This includes the implementation of software-in-the-loop (SIL) and hardware-in-the-loop (HIL) simulations. Based on these reviews, a study on a suspension system control strategy with implementation of the HIL and SIL simulations approach is proposed for future works.

Modeling and Simulation of Swarm Intelligence Algorithms for Parameters Tuning of PID Controller in Industrial Couple Tank System

Industrial tank system is widely used in consumer liquid processing and chemical processing industry. In liquid-based product manufacturing system, one of the main components consists of an industrial tank. This paper explores the applications of two swarm intelligence algorithms in optimizing the PID controller parameters. These swarm intelligence algorithms are Particle Swarm Optimization (PSO) and Firefly Algorithm (FA). Each agent of the swarm intelligence will represent a possible solution of the problem where each dimension corresponds to the PID controllers parameters. Result obtained shows that there are potential in improving these algorithms to replace the conventional way of obtaining PID controllers parameters

Modelling and trajectory following of an armoured vehicle

In this study, a trajectory following strategy consists of two feedback loops is employed on an armoured vehicle to follow a pre-defined trajectory using PID controllers. A 7 Degree-of-Freedoms (DOF) mathematical model is used to model the armoured vehicle which considers full vehicle interactions including tire model, powertrain model, slips and vertical load distribution model. Next, parametric study for the PID parameters was carried out. To tune the PID parameters, two methods are used namely try-and-error based on the parametric study and also using Particle Swarm Optimisation (PSO) algorithm. Lastly, controller responses were evaluated and compared in terms of its performance in following the trajectory. It was proven that PSO algorithm manage to tune and optimise the PID controller parameters for the trajectory following control.

Adaptive modified Stanley controller with fuzzy supervisory system for trajectory tracking of an autonomous armoured vehicle

Abstract In developing path tracking controller for autonomous vehicles, a properly tuned controller will work well for a certain range of driving conditions but may need to be re-tuned for others. This study presents the development of an adaptive controller with fuzzy supervisory system for trajectory tracking control of an autonomous armoured vehicle. A knowledge database is built using Particle Swarm Optimisation which is the mainframe of the Fuzzy supervisory system in adapting to various trajectories and speed. The proposed controller is simulated on a nonlinear vehicle model, and experimental results for the controller are presented to evaluate the proposed controller.

Identification of an optimum control algorithm to reject unwanted yaw effect on wheeled armored vehicle due to the recoil force

This article presents an active safety system for a wheeled armored vehicle to encounter the effect of the firing force. The firing force which acts as an external disturbance causes unwanted yaw moment occurred at the center of gravity of the wheeled armored vehicle. This effect causes the wheeled armored vehicle lose its handling stability and the traveling path after the firing condition. In order to overcome the stability problem, a Firing-On-the-Move assisted by an Active Front Wheel Steering system is proposed in this study. This system is developed based on two established systems, namely, Firing-On-the-Move and Active Front Wheel Steering systems. The proposed system is designed to improve the handling and directional stability performances of the armored vehicle while fires in dynamic condition. Four types of control strategies are designed and investigated in this study to identify the most optimum control strategy as the Firing-On-the-Move assisted by an Active Front Wheel Steering system using optimization tool, genetic algorithm. The control strategies for the Firing-On-the-Move assisted by an Active Front Wheel Steering are evaluated using various types of vehicle speeds and firing angle in order to obtain an appropriate control structure as the Firing-On-the-Move assisted by an Active Front Wheel Steering system for the wheeled armored vehicle.

Thermal Conductivity of Carbon Nanotube Based Nanofluids as Heat Transfer Fluids

Conventional heat transfer fluids such as water and ethylene glycol exhibit low thermal conductivity. These fluids have certain influences on the efficiency of the thermal system. Efficiency of the thermal system is dependent on the thermal conductivity of the heat transfer fluid. New generation of heat transfer fluid such as nanofluid has potential to address this major problem. Therefore in this study, the thermal conductivity characteristic and stability of multiwalled carbon nanotube based water nanofluids was investigated. Two types of surfactants namely gum arabic and sodium dodecylbenzene sulphate (SDBS) were used to stabilize the nanofluid. Findings implied that thermal conductivity of water increases with the loading of multiwalled carbon nanotube nanoparticles. As for the stability, study shows that nanofluids added with SDBS are more stable compared to that of samples with gum Arabic.

Active front wheel steering system for 14 DOF armoured vehicle model due to firing force disturbance

In this paper, a study contributed in controller performance for Active Front Wheel steering System (AFWS) for armoured vehicle. A 14 DOF model of armoured vehicle is used to control the vehicles dynamic responses especially in yaw rate, yaw angle, lateral acceleration and lateral displacement by using a simple PID controller. The responses from the vehicle model was then compared with ones from CarSim software to ensure that the model is verified. All the vehicles parameters were extracted from High mobility Multipurpose Wheeled vehicle (HMMWV) model in CarSim. The external disturbance in this paper is the firing force that exerted on the vehicle body. By tuning the value of PID, the simulation result was obtained and analyzed.

Development of target tracking control of gun-turret system

In a gun-turret system design, the target tracking system characteristic of a gun-turret system is one of the important systems required in most of armored vehicles. Neglecting the target tracking system of an armored vehicle will affect the aiming accuracy of the gun system due to handling and ride disturbance. In this paper, a control system of gun-turret system is developed to overcome the disturbance using the target tracking control. The gun turret mathematical model is developed using Lagrange Theory with two (2) degree-of-freedoms (DOFs) each corresponds to the turntable bearing direction and gun arm elevation angle. The results of this study proves the ability of the 2 DOF gun-turret model to be employed in the target tracking control system during firing condition.

Design and characterisation of external orifice semi-active suspension system for armoured vehicle application

The objective of this paper is to investigate the force-velocity characteristics of a new design of external orifice semi-active suspension system (EOSASS). EOSASS is a class of semi-active system where the orifice area is controlled electronically using an electric motor. The idea of EOSASS is to modify the internal fixed orifice of the existing passive damper into externally controllable using hydraulic unit. The behaviour of the EOSASS is tested in terms of its force-velocity and force-displacement characteristics using Instron 8801 Servohydraulic fatigue testing system and WaveMatrix dynamic testing software. The ratio of the orifice opening area for the compression and extension on the hydraulic unit is varied in order to study the hysteresis behaviour of the damper. From the experimental results, the relationship between the damping force and the ratio of orifice opening during extension and compression are obtained. It was verified that decreasing the ratio of orifice opening will produce higher damping force in both compression and extension stages.