Accession Number : AD0844493

Title :   Experimental System for Automatically Positioning a Microwave-Supported Platform.

Descriptive Note : Final rept. May 66-Jun 68,

Corporate Author : RAYTHEON CO BURLINGTON MA MICROWAVE AND POWER TUBE DIV

Personal Author(s) : Brown, W. C.

Report Date : OCT 1968

Pagination or Media Count : 207

Abstract : An automatic station-keeping subsystem has been developed and successfully tested as an essential part of a larger system, consisting of an airborne platform in the form of a helicopter which is held aloft solely by power derived from a microwave beam. In this automatic station-keeping system a vertical CW microwave beam is employed as a position reference for five of the six degrees of freedom available to a helicopter. The position references provided are for roll, pitch, yaw, and lateral and longitudinal translation. A microwave sensor system aboard the helicopter senses any position error which is then fed into an autopilot. The autopilot uses the error information to actuate controls which restore the helicopter to its proper position with respect to the beam. To achieve the objectives of the study it was necessary to develop (1) an antenna for generating a microwave beam with a Gaussian cross section, (2) microwave sensors for position error detection, (3) an autopilot, (4) a fully articulated helicopter, and (5) adequate test facilities for evaluating the performance of the system. In the absence of external forces the system was demonstrated to hold the helicopter on station to within a small fraction of an inch. Rotational motion was held to less than one degree. In the presence of an external force simulating a gust of wind, the experimental response of the helicopter was similar to that predicted. Steady-state operation was reached within approximately two seconds. The station-keeping system developed is consistent with the concept of using the same microwave beam for both power and a position reference. (Author)

Descriptors :   *FLIGHT CONTROL SYSTEMS), (*STABILIZED PLATFORMS, RADIOFREQUENCY POWER), (*HELICOPTERS, STABILIZATION SYSTEMS, BEAMS(ELECTROMAGNETIC), BEAM RIDER TRAJECTORIES, MICROWAVES, AUTOMATIC PILOTS, AERODYNAMIC CHARACTERISTICS, ERRORS, GUST LOADS.

Subject Categories : Helicopters
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE