T-Rex 600 – The first flight

IMG_4395After finalizing the sensory system and designing mathematical model, the time has come when T-Rex 600 spread its wings and touched the the sky at the first time. The first flight was realized on Rozhnovce airport, which is small field airport near Košice city, on wednesday of 14th April. Forecast predicted a stable and windless weather, ideal time for the first flight after two years of preparations. We had two main goals: 1. Functionality and reliability testing of whole system, because of all control, sensory and communication electronics was completely designed by Smart Robotic Systems 2. Flight data acquisition for mathematical model verification, which we described in our last article about T-Rex Simulator.

Anyone who has piloted the helicopter model knows, that piloting of this type of RC models is the most difficult. And in case, when on the model board is electronics, which price is thousands of euros, the piloting changes to adrenaline sport. So how ended first flights of T-Rex 600?

As we mentioned before, during two years of development, we have designed complete electronics with regards to future fully autonomous operation. So, the first flight was a hard test of our skills from field of designing embedded electronics systems and programming firmware, since all subsystems have to work perfectly during whole flight in environment with strong vibrations caused by helicopter’s rotating parts.

One of the most important subsystems is communication between pilot and the helicopter. We replaced classical RC communication by our own communication modules based on chip NRF905 with frequency 868MHz. The interesting fact is that the main program for piloted flight in our ground station is based on ROS framework, so we can say that reliability test of our electronics was also reliability test of ROS!

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Verification flight consisted of several overflight in low attitude above array of markers. The helicopter pose detection was based on the same principe as in our earlier project of the Parrot A.R. Drone autonomous indoor flight. The sensory system’s main comupter unit saved pose, attitude and pilot’s commands to tiem synchronized table during the flight. This table is very important component in the process of verification mathematical model, because we can compare behaviour of real and mathematical system in the conditions of the same inputs. This comparation allow determine some uknown parameters in mathematical model. This comparison allow determine some unknown parameters in mathematical model.

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At the end, we attach short video with missed landing. We want to emphasize fact, that during piloted flight is not only important right function of all electronics systems, but also the pilot´s skills are very important. Fortunately, this missed landing was only one incident and T-Rex survived all flights without damage.

Ján Bačík