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Many common altitude and airspeed control schemes for an aircraft assume that the altitude and airspeed dynamics are decoupled which leads to errors. The Total Energy Control System (TECS) is an approach that controls the altitude and airspeed by manipulating the total energy rate and energy distribution rate, of the aircraft, in a manner which accounts for the dynamic coupling. In this paper, a nonlinear...
A two step path planning algorithm with collision detection logic for small UAS is proposed. The path planning approach taken in this work is carried out in two steps. In the first step, an initial suboptimal path is generated using A∗ search. In the second step, a chain of unit masses connected by springs and dampers evolves in a simulated force field, using the A∗ solution as an initial condition...
The tailsitter aircraft merges the endurance and speed of fixed-wing aircraft with the flexibility and VTOL abilities of rotorcraft. Typical control and estimation schemes make assumptions about the maximum attitude an aircraft will experience that are not valid for tailsitters. This paper discusses the limitations of a typical EKF magnetometer measurement update that uses Euler angles. It is shown...
The tailsitter is a promising airframe that can take off and land on its tail and transition to level flight. While this ability provides vertical takeoff and landing capabilities with no additional moving parts, it introduces interesting control challenges. In this paper, we look at the attitude control system of a tailsitter in hover flight and show that the behaviour of the aircraft relies on the...
The tailsitter aircraft merges the endurance and speed of fixed-wing aircraft with the flexibility and VTOL abilities of rotorcraft. Because of the requirement to be functional at a full range of attitudes, quaternions are typically employed to calculate attitude error. Attitude control is then accomplished by using the vector component of the error quaternion to drive flight control surfaces. This...
Over the years many aircraft designs have been developed that attempt to merge the endurance and speed of fixed wing aircraft with the flexibility and vertical takeoff and landing abilities of rotor craft. The tail-sitter is one such design. Unlike most other designs, a tail-sitter requires no additional moving parts. However, it trades this mechanical simplicity for increased control complexity....
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