Aeronautical Background of the ESL
Over the past 14 years we have demonstrated various components of the full spectrum of flight automation (take-off, flight, landing, reconfiguration, reliability, etc.) on more than 8 different airframes. At present, students and staff members focus on precision automated-landing onto a moving platform under different wind conditions. The ESL also operates one of two autonomous CSIR Meraka/DPSS modular UAVs. This work is largely supported by Armscor and the CSIR DPSS. The ESL designs, builds and supports a variety of modular and reconfigurable avionics packages in order to perform automated flight testing and demonstration.
Much of the early research into rotary UAV systems at the Electronic Systems Lab (ESL) at Stellenbosch University was conducted by Nicol Carstens, who worked on the instrumentation and basic automation of an electrically powered remote control (RC) helicopter. Using a JR Voyager E Model Helicopter, Carstens was able to demonstrate successful yaw, height and longitudinal position control.
The helicopter used was found to be limited in it’s payload capabilities (and hence ability to carry avionic control and instrumentation systems), as well as suffering from mechanical problems. It was then subsequently replaced with an X-Cell Fury .60 Expert in 2004. The X-Cell helicopter has been used in several studies world-wide and thus, due also to the availability of models and the positive results obtained by Gavrilets et al., the acrobatic model helicopter made a suitable candidate for the project as well as for future work to be completed. As part of his master’s dissertation, Stephanus Groenewald was responsible for the design of an expandable avionics architecture, based on the CAN standard, that allowed for additional sensors and actuators to be added to the system with relative ease. The avionics system was completed in 2005.
In 2008, Carlo van Schalkwyk and Louis-Emile Rossouw investigated different control algorithms to autonomously control the helicopter in flight. They each considered different control structures, and today the helicopter makes use of a tweaked version of the successive loop closure control system designed by Rossouw.