The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 2000
Filed:
Apr. 29, 1998
Bryan S Cotton, Monroe, CT (US);
David M Walsh, Palm City, FL (US);
Sikorsky Aircraft Corporation, Stratford, CT (US);
Abstract
The airspeed limiting performance envelope of a helicopter is converted to a groundspeed envelope by factoring-in the wind speed and direction. A groundspeed command for an unmanned helicopter is provided as a function of the range to the helicopter's destination. The function may be calculated so as to provide a nominal groundspeed command equal to a nominal groundspeed command limit, or the function may be a fixed function to cause the aircraft to creep toward final approach. The cosine and sine of the desired relative flight direction of the aircraft, which is equal to the true bearing to the destination minus the true heading of the aircraft, are utilized to scale the groundspeed command into a longitudinal groundspeed command and a lateral groundspeed command. If one of the groundspeed commands is over a corresponding limit, the other groundspeed command is scaled back so that the vector addition of the two commands will cause flight in the desired direction. Exceedance of either a right or left groundspeed command, as well as saturation of the right or left cyclic pitch channel will cause the aircraft heading to be yawed into the direction of the limit exceedance or channel saturation.