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© 2018, Springer Nature B.V. This paper presents an improved output feedback based image-based visual servoing (IBVS) law for rotorcraft unmanned aerial vehicles (RUAVs). The control law enables a RUAV with a minimal set of sensors, i.e. an inertial measurement unit (IMU) and a single downward facing camera, to regulate its position and heading relative to a planar visual target consisting of multiple points. As compared to our previous work, twofold improvement is made. First, the desired value of the image feature of controlling the vertical motion of the RUAV is a function of other image features instead of a constant. This modification helps to keep the visual target stay in the camera’s field of view by indirectly adjusting the height of the vehicle. Second, the proposed approach simplifies our previous output feedback law by reducing the dimension of the observer filter state space while the same asymptotic stability result is kept. Both simulation and experimental results are presented to demonstrate the performance of the proposed controller.

© 2017 IEEE. This paper presents an improved dynamic output feedback image-based visual servoing (IBVS) law for a quadrotor in comparison with our previous work ('Dynamic Visual Servoing of a Rotary-wing Unmanned Aerial Vehicle Without Velocity Measurement,' in AIAA Guidance, Navigation, and Control Conference, Grapevine, Texas, January, 2017). The controller enables the quadrotor to regulate its position and yaw relative to a planar target consisting of multiple points. This new IBVS controller removes the integral term used to counter external disturbance, in which way the controller's structure is further simplified. Same as in our previous work, the controller requires a minimum set of sensors, i.e., an inertial measurement unit and a single downward facing camera. Also, this approach is adaptive to various unknown system parameters, such as thrust coefficient, mass of the vehicle, and bias errors in Euler angle measurement. The asymptotic stability of error dynamics is proven. Both simulation and experimental results are presented to demonstrate the performance of the proposed controller.

© 1996-2012 IEEE. This paper presents an adaptive output feedback-based visual servoing law for a quadrotor unmanned aerial vehicle equipped with a single downward facing camera. The objective is to regulate the relative position and yaw of the vehicle to a planar target consisting of multiple points using a minimal sensor set, i.e., an inertial measurement unit and a vision sensor. A set of first order image moment features, defined in the image plane of a virtual camera with zero roll and pitch motion, is used for visual servoing. It has been observed in previous work that various system uncertainties, such as aerodynamics constants and attitude estimation bias, result in steady-state errors if not being compensated. By treating those uncertainties as unknown system parameters, an adaptive backstepping controller is developed. As the given visual servoing law is an output feedback controller, the translational velocity measurement from the global position system is not required. The asymptotic stability of the error dynamics is proven. Experimental results are provided to demonstrate the controller performance.