Laith AbuAssi | The Hashemite University (original) (raw)

Papers by Laith AbuAssi

Research paper thumbnail of Control of a quadrotor helicopter using visual feedback

Robotics and Automation, …, Jan 1, 2002

We present control methods for an autonomous four-rotor helicopter, called a quadrotor, using vis... more We present control methods for an autonomous four-rotor helicopter, called a quadrotor, using visual feedback as the primary sensor. The vision system uses a ground camera to estimate the pose (position and orientation) of the helicopter. Two methods of control are studied one using a series of mode-based, feedback linearizing controllers, and the other using a backstepping-like control law. Various simulations of the model demonstrate the implementation of feedback linearization and the backstepping controllers. Finally, we present initial flight experiments where the helicopter is restricted to vertical and yaw motions.

Research paper thumbnail of PID vs LQ control techniques applied to an indoor micro quadrotor

Intelligent Robots and …, Jan 1, 2004

The development of miniature flying robots has become a reachable dream thanks to the new sensing... more The development of miniature flying robots has become a reachable dream thanks to the new sensing and actuating technologies. Micro VTOL 1 systems represent a useful class of flying robots because of their strong abilities for small-area monitoring and building exploration. In this paper, we present the results of two model-based control techniques applied to an autonomous four-rotor micro helicopter called Quadrotor. A classical approach (PID) assuming a simplified dynamics and a modern technique (LQ), based on a more complete model. Various simulations were performed and several tests on the bench validate the control laws. Finally, we present the results of the first test in flight with the helicopter released. These developments are part of the OS4 2 project in our lab 3 .

Research paper thumbnail of Design and control of an indoor micro quadrotor

Robotics and Automation, …, Jan 1, 2004

Recent progress in sensor technology, data processing and integrated actuators has made the devel... more Recent progress in sensor technology, data processing and integrated actuators has made the development of miniature flying robots fully possible. Micro VTOL 1 systems represent a useful class of flying robots because of their strong capabilities for small-area monitoring and building exploration. In this paper we describe the approach that our lab 2 has taken to micro VTOL evolving towards full autonomy, and present the mechanical design, dynamic modelling, sensing, and control of our indoor VTOL autonomous robot OS4 3 .

Research paper thumbnail of Backstepping and sliding-mode techniques applied to an indoor micro quadrotor

Robotics and Automation, 2005. …, Jan 1, 2005

The latest technological progress in sensors, actuators and energy storage devices enables the de... more The latest technological progress in sensors, actuators and energy storage devices enables the developments of miniature VTOL 1 systems. In this paper we present the results of two nonlinear control techniques applied to an autonomous micro helicopter called Quadrotor. A backstepping and a sliding-mode techniques. We performed various simulations in open and closed loop and implemented several experiments on the test-bench to validate the control laws. Finally, we discuss the results of each approach. These developments are part of the OS4 2 project in our lab.

Research paper thumbnail of Quadrotor helicopter flight dynamics and control: Theory and experiment

… , Navigation, and Control …, Jan 1, 2007

Quadrotor helicopters are emerging as a popular platform for unmanned aerial vehicle (UAV) resear... more Quadrotor helicopters are emerging as a popular platform for unmanned aerial vehicle (UAV) research, due to the simplicity of their construction and maintenance, their ability to hover, and their vertical take off and landing (VTOL) capability. Current designs have often considered only nominal operating conditions for vehicle control design. This work seeks to address issues that arise when deviating significantly from the hover flight regime. Aided by well established research for helicopter flight control, three separate aerodynamic effects are investigated as they pertain to quadrotor flight, due to vehicular velocity, angle of attack, and airframe design. They cause moments that affect attitude control, and thrust variation that affects altitude control. Where possible, a theoretical development is first presented, and is then validated through both thrust test stand measurements and vehicle flight tests using the Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) quadrotor helicopter. The results enabled improved controller performance.

Research paper thumbnail of Attitude stabilization of a VTOL quadrotor aircraft

Control Systems Technology, IEEE …, Jan 1, 2006

In this paper, we propose a new quaternion-based feedback control scheme for exponential attitude... more In this paper, we propose a new quaternion-based feedback control scheme for exponential attitude stabilization of a four-rotor vertical takeoff and landing aerial robot known as a quadrotor aircraft. The proposed controller is based upon the compensation of the Coriolis and gyroscopic torques and the use of a PD 2 feedback structure, where the proportional action is in terms of the vector quaternion and the two derivative actions are in terms of the airframe angular velocity and the vector quaternion velocity. We also show that the model-independent PD controller, where the proportional action is in terms of the vector-quaternion and the derivative action is in terms of the airframe angular velocity, without compensation of the Coriolis and gyroscopic torques, provides asymptotic stability for our problem. The proposed controller as well as some other controllers have been tested experimentally on a small-scale quadrotor aircraft.

Research paper thumbnail of Quadrotor control using dual camera visual feedback

Robotics and Automation, …, Jan 1, 2003

In this paper, a vision-based stabilization and output tracking control method for a four-rotor h... more In this paper, a vision-based stabilization and output tracking control method for a four-rotor helicopter has been proposed. A novel 2 camera method has been described for estimating the full 6 DOF pose of the helicopter. This two camera system is consisting of a pan-tilt ground camera and an onboard camera. The pose estimation algorithm is compared in simulation to other methods (such as four point method, and a stereo method) and is shown to be less sensitive to feature detection errors on the image plane. The proposed pose estimation algorithm and nonlinear control techniques have been implemented on a remote controlled quadrotor helicopter.

Research paper thumbnail of Planning in information space for a quadrotor helicopter in a GPS-denied environment

Robotics and Automation, 2008. …, Jan 1, 2008

This paper describes a motion planning algorithm for a quadrotor helicopter flying autonomously w... more This paper describes a motion planning algorithm for a quadrotor helicopter flying autonomously without GPS. Without accurate global positioning, the vehicle's ability to localize itself varies across the environment, since different environmental features provide different degrees of localization. If the vehicle plans a path without regard to how well it can localize itself along that path, it runs the risk of becoming lost.

Research paper thumbnail of Dynamic feedback controller of Euler angles and wind parameters estimation for a quadrotor unmanned aerial vehicle

Robotics and Automation, 2004. …, Jan 1, 2004

A nonlinear dynamic model for a quadrotor nnmanned aerial vehicle b presented with a new vlsion o... more A nonlinear dynamic model for a quadrotor nnmanned aerial vehicle b presented with a new vlsion of state parameter control which is based on Euler angles and open loop positions state observer. This method emphasizes 00 the control of roll, pitch and yaw augle rather than the translational motions of tbe UAV. For tbls reason the system has been presented into two cascade partial parts, the first one relates the rotational motion whose the control law will be applled in a closed loop form and the other one reflects the translational motion. A dynamic feedback controller is developped to transform the dosed loop part of the system into Linear, controllable and decoupled snhsystem. The wind parameters estimation of the quadrotor is used to avoid more sensors. Hence an estimator of resulting aerodynamic moments via Lyapunov function Is developed. Performance and robustness of the proposed controller are tested in slmolntion.

Research paper thumbnail of Control of a quadrotor helicopter using dual camera visual feedback

The International Journal of …, Jan 1, 2005

In this paper we propose a vision-based stabilization and output tracking control method for a mo... more In this paper we propose a vision-based stabilization and output tracking control method for a model helicopter. A novel two-camera method is introduced for estimating the full six-degrees-of-freedom pose of the helicopter. One of these cameras is located on-board the helicopter, and the other camera is located on the ground. Unlike previous work, these two cameras are set to see each other. The pose estimation algorithm is compared in simulation to other methods and is shown to be less sensitive to errors on feature detection. In order to build an autonomous helicopter, two methods of control are studied: one using a series of mode-based, feedback linearizing controllers and the other using a backstepping-like control law. Various simulations demonstrate the implementation of these controllers. Finally, we present flight experiments where the proposed pose estimation algorithm and non-linear control techniques have been implemented on a remote-controlled helicopter.

Research paper thumbnail of Modelling and control of a quad-rotor robot

Proceedings of the Australasian …, Jan 1, 2006

To date, most quad-rotor aerial robots have been based on flying toys. Although such systems can ... more To date, most quad-rotor aerial robots have been based on flying toys. Although such systems can be used as prototypes, they are not sufficiently robust to serve as experimental robotics platforms. We have developed the X-4 Flyer, a quad-rotor robot using custom-built chassis and avionics with off-the-shelf motors and batteries, to be a highly reliable experimental platform. The vehicle uses tuned plant dynamics with an onboard embedded attitude controller to stabilise flight. A linear SISO controller was designed to regulate flyer attitude.

Research paper thumbnail of Multi-agent quadrotor testbed control design: Integral sliding mode vs. reinforcement learning

Intelligent Robots and …, Jan 1, 2005

The Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) is a multi-vehicl... more The Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) is a multi-vehicle testbed currently comprised of two quadrotors, also called X4-flyers, with capacity for eight. This paper presents a comparison of control design techniques, specifically for outdoor altitude control, in and above ground effect, that accommodate the unique dynamics of the aircraft. Due to the complex airflow induced by the four interacting rotors, classical linear techniques failed to provide sufficient stability. Integral Sliding Mode and Reinforcement Learning control are presented as two design techniques for accommodating the nonlinear disturbances. The methods both result in greatly improved performance over classical control techniques.

Research paper thumbnail of Quadrotor using minimal sensing for autonomous indoor flight

Proceedings of the …, Jan 1, 2007

This paper presents a Miniature Aerial Vehicle (MAV) capable of handsoff autonomous operation wit... more This paper presents a Miniature Aerial Vehicle (MAV) capable of handsoff autonomous operation within indoor environments. Our prototype is a Quadrotor weighing approximately 600g, with a diameter of 550mm, which carries the necessary electronics for stability control, altitude control, collision avoidance and anti-drift control. This MAV is equipped with three rate gyroscopes, three accelerometers, one ultrasonic sensor, four infrared sensors, a high-speed motor controller and a flight computer. Autonomous flight tests have been carried out in a 7x6-m room.

Research paper thumbnail of Full control of a quadrotor

Intelligent Robots and Systems, …, Jan 1, 2007

The research on autonomous miniature flying robots has intensified considerably thanks to the rec... more The research on autonomous miniature flying robots has intensified considerably thanks to the recent growth of civil and military interest in Unmanned Aerial Vehicles (UAV). This paper summarizes the final results of the modeling and control parts of OS4 project, which focused on design and control of a quadrotor. It introduces a simulation model which takes into account the variation of the aerodynamical coefficients due to vehicle motion. The control parameters found with this model are successfully used on the helicopter without re-tuning. The last part of this paper describes the control approach (Integral Backstepping) and the scheme we propose for full control of quadrotors (attitude, altitude and position). Finally, the results of autonomous take-off, hover, landing and collision avoidance are presented.

Research paper thumbnail of Estimation and control of a quadrotor vehicle using monocular vision and moire patterns

… , Navigation and Control …, Jan 1, 2006

We present the vision-based estimation and control of a quadrotor vehicle using a single camera r... more We present the vision-based estimation and control of a quadrotor vehicle using a single camera relative to a novel target that incorporates the use of moiré patterns. The objective is to acquire the six degree of freedom estimation that is essential for the operation of vehicles in close proximity to other craft and landing platforms. A target contains markers to determine its relative orientation and locate two sets of orthogonal moiré patterns at two different frequencies. A camera is mounted on the vehicle with the target in the field of view. An algorithm processes the images, extracting the attitude and position information of the camera relative to the target utilizing geometry and four single-point discrete Fourier transforms on the moiré patterns. The position and yaw estimations with accompanying control techniques have been implemented on a remote-controlled quadrotor. The flight tests conducted prove the system's feasibility as an option for precise relative navigation for indoor and outdoor operations.

Research paper thumbnail of Control of a quadrotor mini-helicopter via full state backstepping technique

… and Control, 2006 45th IEEE …, Jan 1, 2006

... Various simulations of a quadrotor show the good performance of the proposed control law. ...... more ... Various simulations of a quadrotor show the good performance of the proposed control law. ... types exist, including the twin rotor or tandem helicopter and the coaxial rotor helicopter ... The quadrotor helicopter, like the one shown in figure 1, has some advantages over conventional ...

Research paper thumbnail of Backstepping control for a quadrotor helicopter

Intelligent Robots and Systems, Jan 1, 2006

... The first reported quadrotor helicopter (Gyroplane No.1) was built in 1907 by the Breguet Bro... more ... The first reported quadrotor helicopter (Gyroplane No.1) was built in 1907 by the Breguet Brothers. However, there was no means of control provided to the pilot other than a throttle for the engine to change the rotor speed, and the stability of the machine was found to be very ...

Research paper thumbnail of Modeling and PD control of a quadrotor VTOL vehicle

Intelligent Vehicles Symposium, 2007 …, Jan 1, 2007

In this paper, we present a model of a four rotor vertical take-off and landing (VTOL) unmanned a... more In this paper, we present a model of a four rotor vertical take-off and landing (VTOL) unmanned air vehicle known as quadrotor aircraft. And we explained its control architecture including vision based control. Quadrotors have generated considerable interest in both the control community due to their complex dynamics and military because of their advantages over regular air vehicles. The proposed dynamical model which comprises gyroscopic effects and its control strategies can be source for future works.

Research paper thumbnail of sliding mode control based on backstepping approach for an UAV type-quadrotor

International Journal of …, Jan 1, 2008

In this paper; we are interested principally in dynamic modelling of quadrotor while taking into ... more In this paper; we are interested principally in dynamic modelling of quadrotor while taking into account the high-order nonholonomic constraints in order to develop a new control scheme as well as the various physical phenomena, which can influence the dynamics of a flying structure. These permit us to introduce a new state-space representation. After, the use of Backstepping approach for the synthesis of tracking errors and Lyapunov functions, a sliding mode controller is developed in order to ensure Lyapunov stability, the handling of all system nonlinearities and desired tracking trajectories. Finally simulation results are also provided in order to illustrate the performances of the proposed controller.

Research paper thumbnail of Distributed cooperative search using information-theoretic costs for particle filters, with quadrotor applications

Proceedings of the AIAA …, Jan 1, 2006

Search and rescue missions can be efficiently and automatically performed by small, highly maneuv... more Search and rescue missions can be efficiently and automatically performed by small, highly maneuverable unmanned aerial vehicle (UAV) teams. The search problem is complicated by a lack of prior information, nonlinear mapping between sensor observations and the physical world, and potentially non-Gaussian sensor noise models. To address these problems, a distributed control algorithm is proposed, using information theoretic methods with particle filters, to compute optimal control inputs for a multi-vehicle, coordinated localization of a stationary target. This technique exploits the structure of the probability distributions of the target state and of the sensor measurements to compute the control inputs that maneuver the UAVs to make observations that minimize the expected future uncertainty of the target state. Because the method directly uses the particle filter state and an accurate sensor noise model to compute the mutual information, it is no longer necessary to discard information by using linear and Gaussian approximations. To ensure safety of the vehicles, the algorithm incorporates collision avoidance and control authority constraints. The resulting information theoretic cost calculation is coupled amongst the vehicles and becomes prohibitive as the size of the UAV team becomes large. Therefore, single vehicle and pairwise approximations to the cost function are used that greatly reduce the computational burden and allow for development of a distributed algorithm for real-time optimization of vehicle trajectories. Simulation results are shown for a bearings-only sensor model with multiple vehicles. Initial flight tests of the Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) show the feasibility of implementation of this algorithm on the quadrotor testbed and in real world situations.

Research paper thumbnail of Control of a quadrotor helicopter using visual feedback

Robotics and Automation, …, Jan 1, 2002

We present control methods for an autonomous four-rotor helicopter, called a quadrotor, using vis... more We present control methods for an autonomous four-rotor helicopter, called a quadrotor, using visual feedback as the primary sensor. The vision system uses a ground camera to estimate the pose (position and orientation) of the helicopter. Two methods of control are studied one using a series of mode-based, feedback linearizing controllers, and the other using a backstepping-like control law. Various simulations of the model demonstrate the implementation of feedback linearization and the backstepping controllers. Finally, we present initial flight experiments where the helicopter is restricted to vertical and yaw motions.

Research paper thumbnail of PID vs LQ control techniques applied to an indoor micro quadrotor

Intelligent Robots and …, Jan 1, 2004

The development of miniature flying robots has become a reachable dream thanks to the new sensing... more The development of miniature flying robots has become a reachable dream thanks to the new sensing and actuating technologies. Micro VTOL 1 systems represent a useful class of flying robots because of their strong abilities for small-area monitoring and building exploration. In this paper, we present the results of two model-based control techniques applied to an autonomous four-rotor micro helicopter called Quadrotor. A classical approach (PID) assuming a simplified dynamics and a modern technique (LQ), based on a more complete model. Various simulations were performed and several tests on the bench validate the control laws. Finally, we present the results of the first test in flight with the helicopter released. These developments are part of the OS4 2 project in our lab 3 .

Research paper thumbnail of Design and control of an indoor micro quadrotor

Robotics and Automation, …, Jan 1, 2004

Recent progress in sensor technology, data processing and integrated actuators has made the devel... more Recent progress in sensor technology, data processing and integrated actuators has made the development of miniature flying robots fully possible. Micro VTOL 1 systems represent a useful class of flying robots because of their strong capabilities for small-area monitoring and building exploration. In this paper we describe the approach that our lab 2 has taken to micro VTOL evolving towards full autonomy, and present the mechanical design, dynamic modelling, sensing, and control of our indoor VTOL autonomous robot OS4 3 .

Research paper thumbnail of Backstepping and sliding-mode techniques applied to an indoor micro quadrotor

Robotics and Automation, 2005. …, Jan 1, 2005

The latest technological progress in sensors, actuators and energy storage devices enables the de... more The latest technological progress in sensors, actuators and energy storage devices enables the developments of miniature VTOL 1 systems. In this paper we present the results of two nonlinear control techniques applied to an autonomous micro helicopter called Quadrotor. A backstepping and a sliding-mode techniques. We performed various simulations in open and closed loop and implemented several experiments on the test-bench to validate the control laws. Finally, we discuss the results of each approach. These developments are part of the OS4 2 project in our lab.

Research paper thumbnail of Quadrotor helicopter flight dynamics and control: Theory and experiment

… , Navigation, and Control …, Jan 1, 2007

Quadrotor helicopters are emerging as a popular platform for unmanned aerial vehicle (UAV) resear... more Quadrotor helicopters are emerging as a popular platform for unmanned aerial vehicle (UAV) research, due to the simplicity of their construction and maintenance, their ability to hover, and their vertical take off and landing (VTOL) capability. Current designs have often considered only nominal operating conditions for vehicle control design. This work seeks to address issues that arise when deviating significantly from the hover flight regime. Aided by well established research for helicopter flight control, three separate aerodynamic effects are investigated as they pertain to quadrotor flight, due to vehicular velocity, angle of attack, and airframe design. They cause moments that affect attitude control, and thrust variation that affects altitude control. Where possible, a theoretical development is first presented, and is then validated through both thrust test stand measurements and vehicle flight tests using the Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) quadrotor helicopter. The results enabled improved controller performance.

Research paper thumbnail of Attitude stabilization of a VTOL quadrotor aircraft

Control Systems Technology, IEEE …, Jan 1, 2006

In this paper, we propose a new quaternion-based feedback control scheme for exponential attitude... more In this paper, we propose a new quaternion-based feedback control scheme for exponential attitude stabilization of a four-rotor vertical takeoff and landing aerial robot known as a quadrotor aircraft. The proposed controller is based upon the compensation of the Coriolis and gyroscopic torques and the use of a PD 2 feedback structure, where the proportional action is in terms of the vector quaternion and the two derivative actions are in terms of the airframe angular velocity and the vector quaternion velocity. We also show that the model-independent PD controller, where the proportional action is in terms of the vector-quaternion and the derivative action is in terms of the airframe angular velocity, without compensation of the Coriolis and gyroscopic torques, provides asymptotic stability for our problem. The proposed controller as well as some other controllers have been tested experimentally on a small-scale quadrotor aircraft.

Research paper thumbnail of Quadrotor control using dual camera visual feedback

Robotics and Automation, …, Jan 1, 2003

In this paper, a vision-based stabilization and output tracking control method for a four-rotor h... more In this paper, a vision-based stabilization and output tracking control method for a four-rotor helicopter has been proposed. A novel 2 camera method has been described for estimating the full 6 DOF pose of the helicopter. This two camera system is consisting of a pan-tilt ground camera and an onboard camera. The pose estimation algorithm is compared in simulation to other methods (such as four point method, and a stereo method) and is shown to be less sensitive to feature detection errors on the image plane. The proposed pose estimation algorithm and nonlinear control techniques have been implemented on a remote controlled quadrotor helicopter.

Research paper thumbnail of Planning in information space for a quadrotor helicopter in a GPS-denied environment

Robotics and Automation, 2008. …, Jan 1, 2008

This paper describes a motion planning algorithm for a quadrotor helicopter flying autonomously w... more This paper describes a motion planning algorithm for a quadrotor helicopter flying autonomously without GPS. Without accurate global positioning, the vehicle's ability to localize itself varies across the environment, since different environmental features provide different degrees of localization. If the vehicle plans a path without regard to how well it can localize itself along that path, it runs the risk of becoming lost.

Research paper thumbnail of Dynamic feedback controller of Euler angles and wind parameters estimation for a quadrotor unmanned aerial vehicle

Robotics and Automation, 2004. …, Jan 1, 2004

A nonlinear dynamic model for a quadrotor nnmanned aerial vehicle b presented with a new vlsion o... more A nonlinear dynamic model for a quadrotor nnmanned aerial vehicle b presented with a new vlsion of state parameter control which is based on Euler angles and open loop positions state observer. This method emphasizes 00 the control of roll, pitch and yaw augle rather than the translational motions of tbe UAV. For tbls reason the system has been presented into two cascade partial parts, the first one relates the rotational motion whose the control law will be applled in a closed loop form and the other one reflects the translational motion. A dynamic feedback controller is developped to transform the dosed loop part of the system into Linear, controllable and decoupled snhsystem. The wind parameters estimation of the quadrotor is used to avoid more sensors. Hence an estimator of resulting aerodynamic moments via Lyapunov function Is developed. Performance and robustness of the proposed controller are tested in slmolntion.

Research paper thumbnail of Control of a quadrotor helicopter using dual camera visual feedback

The International Journal of …, Jan 1, 2005

In this paper we propose a vision-based stabilization and output tracking control method for a mo... more In this paper we propose a vision-based stabilization and output tracking control method for a model helicopter. A novel two-camera method is introduced for estimating the full six-degrees-of-freedom pose of the helicopter. One of these cameras is located on-board the helicopter, and the other camera is located on the ground. Unlike previous work, these two cameras are set to see each other. The pose estimation algorithm is compared in simulation to other methods and is shown to be less sensitive to errors on feature detection. In order to build an autonomous helicopter, two methods of control are studied: one using a series of mode-based, feedback linearizing controllers and the other using a backstepping-like control law. Various simulations demonstrate the implementation of these controllers. Finally, we present flight experiments where the proposed pose estimation algorithm and non-linear control techniques have been implemented on a remote-controlled helicopter.

Research paper thumbnail of Modelling and control of a quad-rotor robot

Proceedings of the Australasian …, Jan 1, 2006

To date, most quad-rotor aerial robots have been based on flying toys. Although such systems can ... more To date, most quad-rotor aerial robots have been based on flying toys. Although such systems can be used as prototypes, they are not sufficiently robust to serve as experimental robotics platforms. We have developed the X-4 Flyer, a quad-rotor robot using custom-built chassis and avionics with off-the-shelf motors and batteries, to be a highly reliable experimental platform. The vehicle uses tuned plant dynamics with an onboard embedded attitude controller to stabilise flight. A linear SISO controller was designed to regulate flyer attitude.

Research paper thumbnail of Multi-agent quadrotor testbed control design: Integral sliding mode vs. reinforcement learning

Intelligent Robots and …, Jan 1, 2005

The Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) is a multi-vehicl... more The Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) is a multi-vehicle testbed currently comprised of two quadrotors, also called X4-flyers, with capacity for eight. This paper presents a comparison of control design techniques, specifically for outdoor altitude control, in and above ground effect, that accommodate the unique dynamics of the aircraft. Due to the complex airflow induced by the four interacting rotors, classical linear techniques failed to provide sufficient stability. Integral Sliding Mode and Reinforcement Learning control are presented as two design techniques for accommodating the nonlinear disturbances. The methods both result in greatly improved performance over classical control techniques.

Research paper thumbnail of Quadrotor using minimal sensing for autonomous indoor flight

Proceedings of the …, Jan 1, 2007

This paper presents a Miniature Aerial Vehicle (MAV) capable of handsoff autonomous operation wit... more This paper presents a Miniature Aerial Vehicle (MAV) capable of handsoff autonomous operation within indoor environments. Our prototype is a Quadrotor weighing approximately 600g, with a diameter of 550mm, which carries the necessary electronics for stability control, altitude control, collision avoidance and anti-drift control. This MAV is equipped with three rate gyroscopes, three accelerometers, one ultrasonic sensor, four infrared sensors, a high-speed motor controller and a flight computer. Autonomous flight tests have been carried out in a 7x6-m room.

Research paper thumbnail of Full control of a quadrotor

Intelligent Robots and Systems, …, Jan 1, 2007

The research on autonomous miniature flying robots has intensified considerably thanks to the rec... more The research on autonomous miniature flying robots has intensified considerably thanks to the recent growth of civil and military interest in Unmanned Aerial Vehicles (UAV). This paper summarizes the final results of the modeling and control parts of OS4 project, which focused on design and control of a quadrotor. It introduces a simulation model which takes into account the variation of the aerodynamical coefficients due to vehicle motion. The control parameters found with this model are successfully used on the helicopter without re-tuning. The last part of this paper describes the control approach (Integral Backstepping) and the scheme we propose for full control of quadrotors (attitude, altitude and position). Finally, the results of autonomous take-off, hover, landing and collision avoidance are presented.

Research paper thumbnail of Estimation and control of a quadrotor vehicle using monocular vision and moire patterns

… , Navigation and Control …, Jan 1, 2006

We present the vision-based estimation and control of a quadrotor vehicle using a single camera r... more We present the vision-based estimation and control of a quadrotor vehicle using a single camera relative to a novel target that incorporates the use of moiré patterns. The objective is to acquire the six degree of freedom estimation that is essential for the operation of vehicles in close proximity to other craft and landing platforms. A target contains markers to determine its relative orientation and locate two sets of orthogonal moiré patterns at two different frequencies. A camera is mounted on the vehicle with the target in the field of view. An algorithm processes the images, extracting the attitude and position information of the camera relative to the target utilizing geometry and four single-point discrete Fourier transforms on the moiré patterns. The position and yaw estimations with accompanying control techniques have been implemented on a remote-controlled quadrotor. The flight tests conducted prove the system's feasibility as an option for precise relative navigation for indoor and outdoor operations.

Research paper thumbnail of Control of a quadrotor mini-helicopter via full state backstepping technique

… and Control, 2006 45th IEEE …, Jan 1, 2006

... Various simulations of a quadrotor show the good performance of the proposed control law. ...... more ... Various simulations of a quadrotor show the good performance of the proposed control law. ... types exist, including the twin rotor or tandem helicopter and the coaxial rotor helicopter ... The quadrotor helicopter, like the one shown in figure 1, has some advantages over conventional ...

Research paper thumbnail of Backstepping control for a quadrotor helicopter

Intelligent Robots and Systems, Jan 1, 2006

... The first reported quadrotor helicopter (Gyroplane No.1) was built in 1907 by the Breguet Bro... more ... The first reported quadrotor helicopter (Gyroplane No.1) was built in 1907 by the Breguet Brothers. However, there was no means of control provided to the pilot other than a throttle for the engine to change the rotor speed, and the stability of the machine was found to be very ...

Research paper thumbnail of Modeling and PD control of a quadrotor VTOL vehicle

Intelligent Vehicles Symposium, 2007 …, Jan 1, 2007

In this paper, we present a model of a four rotor vertical take-off and landing (VTOL) unmanned a... more In this paper, we present a model of a four rotor vertical take-off and landing (VTOL) unmanned air vehicle known as quadrotor aircraft. And we explained its control architecture including vision based control. Quadrotors have generated considerable interest in both the control community due to their complex dynamics and military because of their advantages over regular air vehicles. The proposed dynamical model which comprises gyroscopic effects and its control strategies can be source for future works.

Research paper thumbnail of sliding mode control based on backstepping approach for an UAV type-quadrotor

International Journal of …, Jan 1, 2008

In this paper; we are interested principally in dynamic modelling of quadrotor while taking into ... more In this paper; we are interested principally in dynamic modelling of quadrotor while taking into account the high-order nonholonomic constraints in order to develop a new control scheme as well as the various physical phenomena, which can influence the dynamics of a flying structure. These permit us to introduce a new state-space representation. After, the use of Backstepping approach for the synthesis of tracking errors and Lyapunov functions, a sliding mode controller is developed in order to ensure Lyapunov stability, the handling of all system nonlinearities and desired tracking trajectories. Finally simulation results are also provided in order to illustrate the performances of the proposed controller.

Research paper thumbnail of Distributed cooperative search using information-theoretic costs for particle filters, with quadrotor applications

Proceedings of the AIAA …, Jan 1, 2006

Search and rescue missions can be efficiently and automatically performed by small, highly maneuv... more Search and rescue missions can be efficiently and automatically performed by small, highly maneuverable unmanned aerial vehicle (UAV) teams. The search problem is complicated by a lack of prior information, nonlinear mapping between sensor observations and the physical world, and potentially non-Gaussian sensor noise models. To address these problems, a distributed control algorithm is proposed, using information theoretic methods with particle filters, to compute optimal control inputs for a multi-vehicle, coordinated localization of a stationary target. This technique exploits the structure of the probability distributions of the target state and of the sensor measurements to compute the control inputs that maneuver the UAVs to make observations that minimize the expected future uncertainty of the target state. Because the method directly uses the particle filter state and an accurate sensor noise model to compute the mutual information, it is no longer necessary to discard information by using linear and Gaussian approximations. To ensure safety of the vehicles, the algorithm incorporates collision avoidance and control authority constraints. The resulting information theoretic cost calculation is coupled amongst the vehicles and becomes prohibitive as the size of the UAV team becomes large. Therefore, single vehicle and pairwise approximations to the cost function are used that greatly reduce the computational burden and allow for development of a distributed algorithm for real-time optimization of vehicle trajectories. Simulation results are shown for a bearings-only sensor model with multiple vehicles. Initial flight tests of the Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) show the feasibility of implementation of this algorithm on the quadrotor testbed and in real world situations.