SUBJECT: M.S. Thesis Presentation
   
BY: Christopher Adams
   
TIME: Tuesday, June 12, 2012, 1:00 p.m.
   
PLACE: MARC Building, 201
   
TITLE: Modeling and Control of a Helicopter Carrying a Suspended Load
   
COMMITTEE: Dr. William Singhose, Chair (ME)
Dr. Mark Costello (AE/ME)
Dr. Eric Johnson (AE)
 

SUMMARY

Helicopters are often used to transport supplies and equipment to remote areas. When a heavy load is carried via suspension cables below a helicopter, the load oscillates in response to helicopter motion. This oscillation is dangerous and adversely affects control of the helicopter, especially when carrying heavier loads. By adding a command-filtering method called input shaping to the helicopterís flight controller, the oscillation of the suspended load is greatly reduced. As an added benefit, this approach does not require measurement of the load position. This thesis contains derivations and analysis of simple planar helicopter-load dynamic models, and these models are verified using experimental data from model-scale, radio-controlled helicopters. The effectiveness of input shaping at eliminating suspended load oscillation is then demonstrated on this experimental hardware. In addition, the design of an attitude command, near-hover flight control system that combines input shaping and a common flight control architecture is illustrated using dynamic models of a Sikorsky S-61 helicopter from the literature, and simulation results are shown for example lateral and longitudinal repositioning movements. Results show that applying input shaping to simulated pilot commands greatly improves system performance when carrying a suspended load.