The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain offers hug... more The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain offers huge potential for wider applications in non-segregated airspace. Flying in non-segregated airspace presents a risk of collision with static obstacles (e.g., towers, power lines) and moving obstacles (e.g., aircraft, balloons). In this work, we propose a heuristic cascading fuzzy logic control strategy to solve for the Conflict Detection and Resolution (CD&R) problem, in which the control strategy is comprised of two cascading modules. The first one is Obstacle Avoidance control and the latter is Path Tracking control. Simulation results show that the proposed architecture effectively resolves the conflicts and achieve rapid movement towards the target waypoint. ABSTRAK: Keupayaan mengemudi Kenderaan Udara Tanpa Pemandu (UAV) dengan selamat di kawasan yang tidak diketahui menawarkan potensi yang besar untuk aplikasi yang lebih luas dalam ruang udara yang tidak terasing. Terbang di ruang uda...
An approach that incorporates the Active Force Control (AFC) technique into a conventional Propor... more An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for spacecraft attitude controls. The combined attitude and thermal control system (CATCS) is proposed as an attitude control actuator. All the governing equations are established and the proposed attitude control architecture is made amenable to numerical treatments. The result shows an important attitude pointing enhancement using the AFC technique in CATCS.
ABSTRACT: The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain ... more ABSTRACT: The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain offers huge potential for wider applications in non-segregated airspace. Flying in non-segregated airspace present a risk of collision with static obstacles (e.g., towers, power lines) and moving obstacles (e.g., aircraft, balloons). In this work, we propose a heuristic cascading fuzzy logic control strategy to solve for the Conflict Detection and Resolution (CD&R) problem, in which the control strategy is comprised of two cascading modules. The first one is Obstacle Avoidance control and the latter is Path Tracking control. Simulation results show that the proposed architecture effectively resolves the conflicts and achieve rapid movement towards the target waypoint.ABSTRAK: Keupayaan mengemudi Kenderaan Udara Tanpa Pemandu (UAV) dengan selamat di kawasan yang tidak diketahui menawarkan potensi yang besar untuk aplikasi yang lebih luas dalam ruang udara yang tidak terasing. Terbang di r...
International Journal of Engineering & Technology, 2018
A spacecraft combined attitude and sun tracking system (CASTS) is a synergized system in which so... more A spacecraft combined attitude and sun tracking system (CASTS) is a synergized system in which solar array drive assemblies are used as sun trackers and simultaneously as attitude control actuators. This paper, a continuous research on CASTS, addresses its attitude control problem. The kinematics and dynamics equations of a rigid spacecraft attitude motion is inherently nonlinear. In the attitude regulation problem, the attitude motion can be treated as a simple linear system for a constrained range of operating conditions, but it has impacts on the accuracy of the linear model when a model-based controller is implemented. Naturally, this is a compromise between simplicity and accuracy that all design engineers have to face. In this paper, we present a systematic approach to improve the accuracy while preserving the model as linear as possible, by deriving a quasi-linear approximation of a nonlinear spacecraft attitude motion. The quasi-linear approximation is based on the framework...
International Journal of Engineering & Technology, 2018
In order to fulfil specific mission objective demand, spacecraft performance can be further optim... more In order to fulfil specific mission objective demand, spacecraft performance can be further optimized by means of various methods or configurations. Like for instance, selection of orbit type and inclination with a periodically repeated ground track will ensure the high efficiency of ground target coverage be accomplished throughout the whole duration of mission. Unfortunately, a single monolithic satellite most often unable to accommodate the requirement solicitated by many multi background users. So, to deal with the issue, an alternative solution would be to operate a swarm of satellites flying in synchronized formation. In this paper, three satellites flying in co-planar and non-coplanar formation were simulated. Here, the resulting model of two deputy satellites operating in the same orbital plane but different phase angle moved along the orbit path while both still maintaining constant relative distance with the non-coplanar chief spacecraft throughout the whole orbit period w...
International Journal of Engineering & Technology, 2018
Sliding mode control (SMC) is one of the robust and nonlinear control methods. An aircraft flying... more Sliding mode control (SMC) is one of the robust and nonlinear control methods. An aircraft flying at high angles of attack is considered nonlinear due to flow separations, which cause aerodynamic characteristics in the region to be nonlinear. This paper presents the comparative assessment for the flight control based on linear SMC and integral SMC implemented on the nonlinear longitudinal model of a fighter aircraft. The controller objective is to track the pitch angle and the pitch rate throughout the high angles of attack envelope. Numerical treatments are carried out on selected conditions and the controller performances are studied based on their transient responses. Obtained results show that both SMCs are applicable for high angles of attack.
The world envisions the utilization of practically inexhaustible and global (environmentally) fri... more The world envisions the utilization of practically inexhaustible and global (environmentally) friendly energy that will be compatible with the world population trend and terrestrial supporting capacity. Although the economic and business inertia trend to cling to the lure of non-renewable energy resources, solar power satellite has been viewed as the most promising implementation of green energy sources. Progressive and innovative efforts have been taking place to realize the birth and utilization of solar energy (electricity) through solar power satellite, despite its multitude of challenging issues, and it is proposed here to encirch such effort with rallying all stakeholders to take due participation in such endeavor, including the participation of developing countries. The world's dream of socioeconomic and technological equity is still far from being a reality, and many of the pioneering technology breakthrough for the benefits of mankind, to some extend, contribute to thei...
A 3-axis attitude control for a small satellite using combined attitude and thermal control syste... more A 3-axis attitude control for a small satellite using combined attitude and thermal control system (CATCS) is presented in this paper. The CATCS system is designed to couple the attitude and the thermal control systems in one system. The CATCS principle is based on the use of the onboard excess heat to circulate a fluid inside a closed duct under the influence of generated current and magnetic flux fields. Till to date, the use of CATCS has been demonstrated for a single axis attitude control of a small satellite. The complete onboard 3-axis attitude control architecture based on the PI-controllers is implemented and numerically tested to enhance the closed-loop attitude control response of a satellite. The simulated attitude performances show that the CATCS system is able to perform the 3-axis attitude control of a satellite.
The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain offers hug... more The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain offers huge potential for wider applications in non-segregated airspace. Flying in non-segregated airspace presents a risk of collision with static obstacles (e.g., towers, power lines) and moving obstacles (e.g., aircraft, balloons). In this work, we propose a heuristic cascading fuzzy logic control strategy to solve for the Conflict Detection and Resolution (CD&R) problem, in which the control strategy is comprised of two cascading modules. The first one is Obstacle Avoidance control and the latter is Path Tracking control. Simulation results show that the proposed architecture effectively resolves the conflicts and achieve rapid movement towards the target waypoint. ABSTRAK: Keupayaan mengemudi Kenderaan Udara Tanpa Pemandu (UAV) dengan selamat di kawasan yang tidak diketahui menawarkan potensi yang besar untuk aplikasi yang lebih luas dalam ruang udara yang tidak terasing. Terbang di ruang uda...
An approach that incorporates the Active Force Control (AFC) technique into a conventional Propor... more An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for spacecraft attitude controls. The combined attitude and thermal control system (CATCS) is proposed as an attitude control actuator. All the governing equations are established and the proposed attitude control architecture is made amenable to numerical treatments. The result shows an important attitude pointing enhancement using the AFC technique in CATCS.
ABSTRACT: The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain ... more ABSTRACT: The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain offers huge potential for wider applications in non-segregated airspace. Flying in non-segregated airspace present a risk of collision with static obstacles (e.g., towers, power lines) and moving obstacles (e.g., aircraft, balloons). In this work, we propose a heuristic cascading fuzzy logic control strategy to solve for the Conflict Detection and Resolution (CD&R) problem, in which the control strategy is comprised of two cascading modules. The first one is Obstacle Avoidance control and the latter is Path Tracking control. Simulation results show that the proposed architecture effectively resolves the conflicts and achieve rapid movement towards the target waypoint.ABSTRAK: Keupayaan mengemudi Kenderaan Udara Tanpa Pemandu (UAV) dengan selamat di kawasan yang tidak diketahui menawarkan potensi yang besar untuk aplikasi yang lebih luas dalam ruang udara yang tidak terasing. Terbang di r...
International Journal of Engineering & Technology, 2018
A spacecraft combined attitude and sun tracking system (CASTS) is a synergized system in which so... more A spacecraft combined attitude and sun tracking system (CASTS) is a synergized system in which solar array drive assemblies are used as sun trackers and simultaneously as attitude control actuators. This paper, a continuous research on CASTS, addresses its attitude control problem. The kinematics and dynamics equations of a rigid spacecraft attitude motion is inherently nonlinear. In the attitude regulation problem, the attitude motion can be treated as a simple linear system for a constrained range of operating conditions, but it has impacts on the accuracy of the linear model when a model-based controller is implemented. Naturally, this is a compromise between simplicity and accuracy that all design engineers have to face. In this paper, we present a systematic approach to improve the accuracy while preserving the model as linear as possible, by deriving a quasi-linear approximation of a nonlinear spacecraft attitude motion. The quasi-linear approximation is based on the framework...
International Journal of Engineering & Technology, 2018
In order to fulfil specific mission objective demand, spacecraft performance can be further optim... more In order to fulfil specific mission objective demand, spacecraft performance can be further optimized by means of various methods or configurations. Like for instance, selection of orbit type and inclination with a periodically repeated ground track will ensure the high efficiency of ground target coverage be accomplished throughout the whole duration of mission. Unfortunately, a single monolithic satellite most often unable to accommodate the requirement solicitated by many multi background users. So, to deal with the issue, an alternative solution would be to operate a swarm of satellites flying in synchronized formation. In this paper, three satellites flying in co-planar and non-coplanar formation were simulated. Here, the resulting model of two deputy satellites operating in the same orbital plane but different phase angle moved along the orbit path while both still maintaining constant relative distance with the non-coplanar chief spacecraft throughout the whole orbit period w...
International Journal of Engineering & Technology, 2018
Sliding mode control (SMC) is one of the robust and nonlinear control methods. An aircraft flying... more Sliding mode control (SMC) is one of the robust and nonlinear control methods. An aircraft flying at high angles of attack is considered nonlinear due to flow separations, which cause aerodynamic characteristics in the region to be nonlinear. This paper presents the comparative assessment for the flight control based on linear SMC and integral SMC implemented on the nonlinear longitudinal model of a fighter aircraft. The controller objective is to track the pitch angle and the pitch rate throughout the high angles of attack envelope. Numerical treatments are carried out on selected conditions and the controller performances are studied based on their transient responses. Obtained results show that both SMCs are applicable for high angles of attack.
The world envisions the utilization of practically inexhaustible and global (environmentally) fri... more The world envisions the utilization of practically inexhaustible and global (environmentally) friendly energy that will be compatible with the world population trend and terrestrial supporting capacity. Although the economic and business inertia trend to cling to the lure of non-renewable energy resources, solar power satellite has been viewed as the most promising implementation of green energy sources. Progressive and innovative efforts have been taking place to realize the birth and utilization of solar energy (electricity) through solar power satellite, despite its multitude of challenging issues, and it is proposed here to encirch such effort with rallying all stakeholders to take due participation in such endeavor, including the participation of developing countries. The world's dream of socioeconomic and technological equity is still far from being a reality, and many of the pioneering technology breakthrough for the benefits of mankind, to some extend, contribute to thei...
A 3-axis attitude control for a small satellite using combined attitude and thermal control syste... more A 3-axis attitude control for a small satellite using combined attitude and thermal control system (CATCS) is presented in this paper. The CATCS system is designed to couple the attitude and the thermal control systems in one system. The CATCS principle is based on the use of the onboard excess heat to circulate a fluid inside a closed duct under the influence of generated current and magnetic flux fields. Till to date, the use of CATCS has been demonstrated for a single axis attitude control of a small satellite. The complete onboard 3-axis attitude control architecture based on the PI-controllers is implemented and numerically tested to enhance the closed-loop attitude control response of a satellite. The simulated attitude performances show that the CATCS system is able to perform the 3-axis attitude control of a satellite.
Uploads
Papers