|The University of Adelaide||Home | Departments | Search|
(Commenced: 01-Mar-2006,Concluded: 01-Nov-2006)
This honours project involved the design, build and control of a VTOL craft capable of stable hover in six degrees of freedom, named the WASP. The thrust is generated by an electric motor driving a five inch Dynamax ducted fan and attitude stability is achieved through deflections of aerofoils placed in the fan efflux. The selected fan was tested to obtain a thrust/speed characteristic, which was extrapolated to determine the thrust attainable. A mass budget was established and the fan characteristic analysed to select a motor capable of driving the fan to the speeds required.
The objective of the platform design was to optimise the dynamic performance of the craft in hover such that it was most easily controllable. An analysis of the desirable location for craft centre of gravity supported the decision to mount the motor in a top drive manner, unconventional to the particular fan used. This added to the considerable mechanical design challenges of providing structural rigidity given that thrust limitations of the fan placed a strict weight budget on any structural components.
The detailed dynamics of the craft were derived and linearised in order to form a strategy for full six degree of freedom control. The controller was formulated from classical control techniques, although other modern model-based methodologies are investigated. Thrust vectoring techniques are used to allow command following in horizontal translation.
Following the construction of the craft, a series of system identification experiments were devised and conducted to obtain estimates for craft parameters used in the dynamic modelling. These values were verified from multiple sources where possible, to increase accuracy and validate controller simulations based on the mathematical model of the craft.
Dynamic testing of the craft commenced on a ball joint configuration, where a yaw controller was tuned, as were gains for feedforward compensation of the gyroscopic moment on both pitch and roll axes.
The project goals were highly ambitious within the time frame available and although full six degree control has not been achieved there has been a considerable amount of groundwork laid for future work either on the WASP, or a larger similar craft.