PID vs LQR controller for tilt rotor airplane

The main thematic of this paper is controlling the main manoeuvers of a tilt rotor UAV airplane in several modes such as vertical takeoff and landing, longitudinal translation and the most important phase which deal with the transition from the helicopter mode to the airplane mode and visversa based on a new actuators combination technique for specially the yaw motion with not referring to rotor speed control strategy which is used in controlling the attitude of a huge number of vehicles nowadays. This new actuator combination is inspired from that the transient response of a trirotor using tilting motion dynamics provides a faster response than using rotor speed dynamics. In the literature, a lot of control technics are used for stabilizing and guarantee the necessary manoeuvers for executing such task, a multiple Attitude and Altitude PID controllers were chosen for a simple linear model of our tilt rotor airplane in order to fulfill the desired trajectory, for reasons of complexity of our model the multiple PID controller doesnt take into consideration all the coupling that exists between the degrees of freedom in our model, so an LQR controller is adopted for more feasible solution of complex manoeuvering, the both controllers need linearization of the model for an easy implementation

Validation of Quad Tail-sitter VTOL UAV Model in Fixed Wing Mode

Vertical take-off and landing (VTOL) is a type of unmanned aerial vehicle (UAV) that is growing rapidly because its ability to take off and land anywhere in tight spaces. One type of VTOL UAV, the tail-sitter, has the best efficiency. However, besides the efficiency offered, some challenges must still be overcome, including the complexity of combining the ability to hover like a helicopter and fly horizontally like a fixed-wing aircraft. This research has two contributions: in the form of how the analytical model is generated and the tools used (specifically for the small VTOL quad tail-sitter UAV) and how to utilize off-the-shelf components for UAV empirical modeling. This research focuses on increasing the speed and accuracy of the UAV VTOL control design in fixed-wing mode. The first step is to carry out analysis and simulation. The model is analytically obtained using OpenVSP in longitudinal and lateral modes. The next step is to realize this analytical model for both the aircraft and the controls. The third step is to measure the flight characteristics of the aircraft. Based on the data recorded during flights, an empirical model is made using system identification technique. The final step is to vali-date the analytical model with the empirical model. The results show that the characteristics of the analytical mode fulfill the specified requirements and are close to the empirical model. Thus, it can be concluded that the analytical model can be implemented directly, and consequently, the VTOL UAV design and development process has been shortened

Flight Test Evaluation for Tilt Rotor Unmanned Aerial Vehicle Development

Tiltrotor Unmanned Aerial Vehicle (UAV) is type of UAV that combine fixed wing (FW) and multirotor (VTOL) configuration in order to be able to perform instant transition from one configuration to another. Tiltrotor UAV has advantage to perform takeoff and landing from limited space such as plantation farm, forest, and residential area. Tiltrotor also can carry various mission since it has 2 configuration such as cargo drone, safer payload dropping, and mapping. In this research tiltrotor UAV designed with ruddervator (V-Tail) configuration with 3 motors in total, 2 motors placed on main wing with tilting capability and 1 motor placed at the end of fuselage as pitch controller in VTOL mode. Test flight will be conducted and evaluated to test UAV capability in hovering and transition from one mode to anothe

Flight control of hybrid drones towards enabling parcel relay manoeuvres

This work addresses the modeling and controlling process of a hybrid UAV, aimed for parcel relay maneuvers. Hybrid UAVs bring big advantages with the capability of flying in two flight modes, rotary and fixed wing. But with them comes added complexity both in modeling and controlling. This work is based on a popular airframe, a tilt tri-rotor UAV, containing all the specific system dynamics such vehicle category provides. The model is then validated by designing two separate controllers for both flight modes, capable of trajectory tracking in eachmode,makinguseofacustomhybridcontrolallocationtechniquethatdifferentiates the control in three parts: vertical, horizontal, and transitional flight modes. Finally, a hybrid controller is proposed, using a finite state machine capable of handling logical events, with the aim to provide control logic to perform autonomous mid flight transitions. All the designs system are simulated using a mathematical framework and a power-full simulation tool.Este trabalho aborda o processo de modelação e controlo de um veículo aéreo não tripulado híbrido com o objetivo de proporcionar manobras de transição de carga. Drones híbridos trazem grandes vantagem com a sua capacidade de voar em dois modos de voo, de asa rotativa e asa fixa. Por outro lado, estas vantagens adicionam complexidade ao sistema dificultando o processo de modulação e controlo. Nestetrabalhoestápresenteummodelodeumdronetrirotortendodoisrotoresmovíveis. Este contém todas as dinâmicas especificas que um sistema deesta categoria de UAV obriga. O modelo é posteriormente validado com dois controladores separados em modo de voo, capazes de proporcionar medidas de seguimento de trajetória em cada modo, usando uma técnica de alocação de controlo personalizada que diferencia o controlo em três partes: vertical, horizontal e de transição. Por fim, é proposto um controlador híbrido contento uma máquina de estados capaz de tratar de eventos lógicos, de modo a proporcionar transições de modo de voo autónomas em pleno voo. Todos os sistemas propostos são devidamente simulados usando ferramentas matemáticas e também poderosos sistemas de simulação

GPS based position control and waypoint navigation of a quad tilt-wing UAV

Unmanned aerial vehicles (UAV) are becoming increasingly capable nowadays and the civilian applications and the military tasks that can be carried out by these vehicles are far more critical than before. There have been remarkable advances in the design and development of UAVs. They are equipped with various sensors which make them capable of accomplishing missions in unconstrained environments which are dangerous or effortful for manned aircrafts. Recently, significant interest in unmanned aerial vehicles has directed researchers towards navigation problem of flying vehicles. This thesis work focuses on GPS based position control and waypoint navigation of a quad tilt-wing unmanned aerial vehicle (SUAVI: Sabanci University Unmanned Aerial Vehicle). The vehicle is capable of vertical take-off and landing (VTOL). It can also fly horizontally due to its tilt-wing structure. Mechanical and aerodynamic designs are first outlined. A nonlinear mathematical model expressed in a hybrid frame is then obtained using Newton-Euler formulation which also includes aerodynamics effects such as wind and gusts. Extended Kalman filtering (EKF) using raw IMU measurements is employed to obtain reliable orientation estimates which is crucial for attitude stabilization of the aerial vehicle. A high-level acceleration controller which utilizes GPS data produces roll and pitch references for the low-level attitude controllers for hovering and trajectory tracking of the aerial vehicle. The nonlinear dynamic equations of the vehicle are linearized around nominal operating points in hovering conditions and gravity compensated PID controllers are designed for position and attitude control. Simulations and several real flight experiments demonstrate success of the developed position control algorithms

Helicopter Autonomous Ship Landing System

This research focuses on developing a helicopter autonomous ship landing algorithm based on the real helicopter ship landing procedure which is already proven and currently used by Navy pilots. It encompasses the entire ship landing procedure from approach to landing using a pilot-inspired vision-based navigation system. The present thesis focuses on the first step towards achieving this overarching objective, which involves modeling the flight dynamics and control of a helicopter and some preliminary simulations of a UH-60 (Blackhawk) helicopter landing on a ship. The airframe of the helicopter is modeled as a rigid body along with rotating articulated blades that can undergo flap, lag and pitch motions about the root. A UH-60 helicopter is used for a representative model due to its ample simulation and flight test data. Modeling a UH-60 helicopter is based on Blade Element Momentum Theory (BEMT), rotor aerodynamics with the Pitt-Peters linear inflow model, empennage aerodynamics and rigid body dynamics for fuselage. For the blade dynamics, the cyclic (1/rev) and collective pitch motions are prescribed and the blade (1/rev) flap and lag motions are obtained as a response to the aerodynamic and inertial forces. The helicopter control inputs and translational and attitude dynamics obtained from the model are validated with flight test data at various speeds and attitude. A linearized model is extracted based on a first-order Taylor series expansion of the nonlinear system about an equilibrium point for the purpose of determining the stability of the dynamic system, investigating sensitivity to gusts, and designing a model-based flight control system. Combined vision-based navigation and Linear Quadratic Regulator (LQR) for set-point tracking is used for disturbance rejection and tracking states. A rotatable camera is used for identifying the relative position of the helicopter with respect to the ship. Based on the position, a corresponding trajectory is computed. Considering the trade-off between transient responses and control efforts, gains for the LQR controller are chosen carefully and realistically. A fully autonomous flight is simulated from approach to landing on a ship. It consists of initial descent, steady forward flight, steady coordinated turn, deceleration, and final landing. Corresponding to each maneuver, relevant linearized model is used and gains are tuned. By using X-plane flight simulator program, the simulation data which include fuselage attitude and position at each time step are visualized with a single flight deck ship. This method allows an aircraft to land on a ship autonomously while maintaining high level of safety and accuracy without the need to capture the ship deck motions, however, by using a camera, and any other additional sensors, which will provide the accurate location of the ship relative to the helicopter. This method is not only relevant for a particular helicopter, but for any types of VTOL aircraft, manned or unmanned. Hence, it can improve the level of safety by preventing human errors that may occur during landing on a ship

Helicopter Autonomous Ship Landing System

This research focuses on developing a helicopter autonomous ship landing algorithm based on the real helicopter ship landing procedure which is already proven and currently used by Navy pilots. It encompasses the entire ship landing procedure from approach to landing using a pilot-inspired vision-based navigation system. The present thesis focuses on the first step towards achieving this overarching objective, which involves modeling the flight dynamics and control of a helicopter and some preliminary simulations of a UH-60 (Blackhawk) helicopter landing on a ship. The airframe of the helicopter is modeled as a rigid body along with rotating articulated blades that can undergo flap, lag and pitch motions about the root. A UH-60 helicopter is used for a representative model due to its ample simulation and flight test data. Modeling a UH-60 helicopter is based on Blade Element Momentum Theory (BEMT), rotor aerodynamics with the Pitt-Peters linear inflow model, empennage aerodynamics and rigid body dynamics for fuselage. For the blade dynamics, the cyclic (1/rev) and collective pitch motions are prescribed and the blade (1/rev) flap and lag motions are obtained as a response to the aerodynamic and inertial forces. The helicopter control inputs and translational and attitude dynamics obtained from the model are validated with flight test data at various speeds and attitude. A linearized model is extracted based on a first-order Taylor series expansion of the nonlinear system about an equilibrium point for the purpose of determining the stability of the dynamic system, investigating sensitivity to gusts, and designing a model-based flight control system. Combined vision-based navigation and Linear Quadratic Regulator (LQR) for set-point tracking is used for disturbance rejection and tracking states. A rotatable camera is used for identifying the relative position of the helicopter with respect to the ship. Based on the position, a corresponding trajectory is computed. Considering the trade-off between transient responses and control efforts, gains for the LQR controller are chosen carefully and realistically. A fully autonomous flight is simulated from approach to landing on a ship. It consists of initial descent, steady forward flight, steady coordinated turn, deceleration, and final landing. Corresponding to each maneuver, relevant linearized model is used and gains are tuned. By using X-plane flight simulator program, the simulation data which include fuselage attitude and position at each time step are visualized with a single flight deck ship. This method allows an aircraft to land on a ship autonomously while maintaining high level of safety and accuracy without the need to capture the ship deck motions, however, by using a camera, and any other additional sensors, which will provide the accurate location of the ship relative to the helicopter. This method is not only relevant for a particular helicopter, but for any types of VTOL aircraft, manned or unmanned. Hence, it can improve the level of safety by preventing human errors that may occur during landing on a ship

Helicopter Autonomous Ship Landing System

This research focuses on developing a helicopter autonomous ship landing algorithm based on the real helicopter ship landing procedure which is already proven and currently used by Navy pilots. It encompasses the entire ship landing procedure from approach to landing using a pilot-inspired vision-based navigation system. The present thesis focuses on the first step towards achieving this overarching objective, which involves modeling the flight dynamics and control of a helicopter and some preliminary simulations of a UH-60 (Blackhawk) helicopter landing on a ship. The airframe of the helicopter is modeled as a rigid body along with rotating articulated blades that can undergo flap, lag and pitch motions about the root. A UH-60 helicopter is used for a representative model due to its ample simulation and flight test data. Modeling a UH-60 helicopter is based on Blade Element Momentum Theory (BEMT), rotor aerodynamics with the Pitt-Peters linear inflow model, empennage aerodynamics and rigid body dynamics for fuselage. For the blade dynamics, the cyclic (1/rev) and collective pitch motions are prescribed and the blade (1/rev) flap and lag motions are obtained as a response to the aerodynamic and inertial forces. The helicopter control inputs and translational and attitude dynamics obtained from the model are validated with flight test data at various speeds and attitude. A linearized model is extracted based on a first-order Taylor series expansion of the nonlinear system about an equilibrium point for the purpose of determining the stability of the dynamic system, investigating sensitivity to gusts, and designing a model-based flight control system. Combined vision-based navigation and Linear Quadratic Regulator (LQR) for set-point tracking is used for disturbance rejection and tracking states. A rotatable camera is used for identifying the relative position of the helicopter with respect to the ship. Based on the position, a corresponding trajectory is computed. Considering the trade-off between transient responses and control efforts, gains for the LQR controller are chosen carefully and realistically. A fully autonomous flight is simulated from approach to landing on a ship. It consists of initial descent, steady forward flight, steady coordinated turn, deceleration, and final landing. Corresponding to each maneuver, relevant linearized model is used and gains are tuned. By using X-plane flight simulator program, the simulation data which include fuselage attitude and position at each time step are visualized with a single flight deck ship. This method allows an aircraft to land on a ship autonomously while maintaining high level of safety and accuracy without the need to capture the ship deck motions, however, by using a camera, and any other additional sensors, which will provide the accurate location of the ship relative to the helicopter. This method is not only relevant for a particular helicopter, but for any types of VTOL aircraft, manned or unmanned. Hence, it can improve the level of safety by preventing human errors that may occur during landing on a ship