We present the design and implementation of a real-time, vision-based landing algorithm for an autonomous helicopter. The landing algorithm is integrated with algorithms for visual acquisition of the target (a helipad), and navigation to the target, from an arbitrary initial position and orientation. We use vision for precise target detection and recognition, and a combination of vision and GPS...

Photoclinometry was used to analyze the small-scale roughness of areas that fall within the proposed Mars Exploration Rover (MER) 2003 landing ellipses. The landing ellipses presented in this study were those in Athabasca Valles, Elysium Planitia, Eos Chasma, Gusev Crater, Isidis Planitia, Melas Chasma, and Meridiani Planum. We were able to constrain surface slopes on length scales comparable t...

Cytotoxic activity of non-major histocompatibility complex-restricted (CD56+) (NMHC) killer cells and cell surface marker expression of peripheral blood mononuclear cells were determined before and after spaceflight. Ten astronauts (9 men, 1 woman) from two space shuttle missions (9- and 10-day duration) participated in the study. Blood samples were collected 10 days before launch, within 3 h a...

Responses of the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Culex nigripalpus to volatiles and compounds associated with bovine and avian blood that were presented in collagen membranes were evaluated in olfactometer and landing assays. The presence of attractants produced by blood was supported by more attraction of all species to blood than water controls in the olfactometer. Femal...

The paper presents the automatic control of aircraft in longitudinal plane, during landing, by using the linearized dynamics of aircraft, taking into consideration the sensor errors and other external disturbances. Aircraft auto-landing is achieved by combining two control techniques: H2 and H∞ approaches; this way, a robust H2/H∞ controller is obtained. Within the robust H2/H∞ controller, the ...

The atmospheric disturbances affect not only flying qualities of an airplane but also flight safety. According to flight records, most aircraft accidents occurred during final approach or landing. If the flight conditions are beyond the preset envelope, the automatic landing system (ALS) is disabled and the pilot takes over. An inexperienced pilot may not be able to guide the aircraft to a safe...

Synopsis Anything that jumps must land, but unlike during jumping when muscles produce energy to accelerate the body into the air, controlled landing requires muscles to dissipate energy and decelerate the body. Among anurans, toads (genus Bufo) exhibit highly coordinated landing behaviors, using their forelimbs to stabilize the body after touch-down as they lower their hindlimbs to the ground....

Random errors are omnipresent in sensorimotor tasks due to perceptual and motor noise. The question is, are humans aware of their random errors on an instance-by-instance basis? The appealing answer would be 'no' because it seems intuitive that humans would otherwise immediately correct for the errors online, thereby increasing sensorimotor precision. However, here we show the opposite. Partici...

Just over three hundred years ago, William of Orange seized the British crown for himself and his wife Mary Stuart from his uncle and father-in-law, James II. In a virtually bloodless take-over, William's coup placed firm Protestants on a throne that had been occupied by a Catholic monarch ruling in an increasingly autocratic manner without Parliament and in contempt of the Established Church-a...