WP1.1: Conceptual Design
In WP1.1 the challenges required by the project objectives have to be addressed. The quadrotor (or multi-rotor) can be built as 4-, 6- or 8- rotor aircraft. The appropriate mechanical concept, batteries, motors, propellers with flight time calculations and the payload have to be defined. The low-level electronics requires an investigation on available hardware chips (microcontrollers, sensors, peripherals) and an overall concept review based on already built low-level stabilization electronics.
A big challenge is the vision hardware. Before the division between onboard and off-board processing can be made, a concept of a possible onboard solution has to be made. Getting enough processing power onboard to do at least part of the vision processing requires a very lightweight and energy efficient hardware design with high performance and complex processor or FPGA hardware systems.
A part of a possible vision hardware could be an optimized digital video link with preprocessed images. Several approaches of how to transmit onboard data to the ground and between vehicles have to be evaluated in cooperation with WP3.
The mechanical design requires modeling the helicopter mechanics for analysis and production. This is done with a CAD/CAM system. The development and production steps can be optimized, as well as the flight time and mechanical robustness can be simulated.
Micro helicopters are challenging to control for three reasons; they are under actuated, non-linear and subject to large disturbances. In order to be autonomous, a micro helicopter has to be able to take off vertically, hover and fly in reasonable air disturbances and this comes at the expense of greatly increased modeling and control complexity. In the particular case of a quadrotor helicopter, it is under-actuated and non-holonomic. It can be flown directly to any position x, y, z in space and its yaw angle can be independently controlled. Its roll and pitch directly determine its lateral acceleration and hence these parameters cannot be independently controlled. The complete list of control variables is as follows:
WP1.4: Integration and Testing
During the development of several prototypes, all multi-rotor helicopters have to go through intensive flight and robustness testing. During the different phases of the project all payload has to be integrated and tested in flight. Several prototypes will be delivered to other partners for their tests and integration. All hardware has to be planned for medium quantity production (10-20 units) during the project time.