Development and validation of a test bench for Attitude Determination and Control System for small satellite

In the last decades, nanosatellites have made space accessible to a wide public thanks to their low cost and fast development time, compared to traditional satellites, profoundly changing both the market and the space industry. Since their inception, they have played an important role in the so-called new space economy. In particular, CubeSats nanosatellites, thanks to their standardisation, evolved from being simple educational tools to being used in multiple space applications. Thanks to their use in constellations with increasing success, CubeSats offer a valid alternative to traditional spacecraft in areas of great scientific-application relevance. One of the most complex and challenging subsystems in CubeSats is the Attitude Determination and Control System (ADCS). This subsystem employs complex components, involving highly integrated hardware and software. Its testing is particularly challenging since it requires a free-rotational motion in a low-torque environment of the satellite and a physical stimulus of the sensors. This thesis fits into the context of Hardware-In-The-Loop (HIL) ADCS testing. The first objective consisted of the update of the subsystem test facility already implemented at the Microsatellites and Space Microsystems Laboratory of the University of Bologna. The upgrade consisted of an improvement in the facility performance in terms of minimization of the disturbance torques and the introduction of a mechanical interface that allows the hosting of nanosatellites compliant with the CubeSat standard, in the broader perspective of a nationwide distributed laboratory. The first part of the work has been therefore focused on the design and selection of the new components of the facility with the subsequent work of verification, integration and validation. Taking into account that for an air-bearing type facility, the biggest disturbance torque is the one due to gravity and the misalignment between the centre of rotation and the centre of mass, a minimization of the torque is obtained by minimizing the distance between CM and CR. A balancing procedure employing three sliding masses, moved by three stepper motors, is used to minimize such torque. As a further work, an embedded PCB has been designed to reduce the presence of moving cables that could affect the disturbance torque acting on the facility. In the second part of the thesis, the magnetic actuators have been dimensioned taking into consideration the residual disturbance torque of the facility. Moreover, a single axis control law was implemented in the ADCS board and its effectiveness has been verified through HIL tests. A further work saw the testing of proper torque generation by air-coil magnetic actuators. The purpose of the test is to verify that the control torque is suitable to set back the system from a tilted angle configuration to the equatorial one.