Drone and method of controlling flight of a drone

Abstract

According to the present invention there is provided a drone () comprising one or more propellers () and one or more actuators () for actuating said one or more propellers () to generating a thrust force which enables the drone () to fly; a controller () which is configured such that it can control the flight of the drone (), wherein the controller () comprises a memory () having stored therein a plurality of predefined sets of positions which define a virtual rail which can be used to guide the flight of the drone () so that the drone can avoid collision with an subject; and wherein the controller further comprises a mathematical model () of the drone; wherein the controller () is configured to control the flight of the drone by performing at least the following steps, (a) approximating lag error based on the position of the drone () measured by a sensor () and the virtual rail, wherein the lag error is the distance between a point along the virtual rail which is closest to the drone () and an estimate of said point along the virtual rail which is closest to the drone (); (b) approximating a contour error based on the position of the drone () as measured by a sensor () and the virtual rail, wherein the contour error is the distance between a point along the virtual rail which is closest to the drone () and the position of the drone (); (c) defining a cost function which comprises at least said approximation of the lag error and said approximation of the contour error; (d) minimizing the defined cost function, while also respecting at least limitations of the drone which are defined in said mathematical model, to determine a plurality of control inputs over a predefined time period into the future, and (e) applying the first control input only to the one or more actuators (). There is further provided a corresponding method for controlling the flight of a drone.