A Physical Testbed to Aid in Developing Advanced Control Algorithms for Space Vehicles
To meet the advancing ambitions of space missions, all aspects of the missions must improve. Of critical importance is the guidance, navigation, and control (GNC) algorithms that handle the complicated dynamics of space launch and landing vehicles (LLVs). Currently, there is a lack of systems that are capable of bridging these algorithms from simulation of theory, to full-fledged flight testing. The Cost- and Risk-Reducing Quadcopter System (CRQS) aims to address this absence. By attaching an inverted and hanging pendulum to the quadcopter, the system dynamics mimic that of LLVs. CRQS exists as a numerical simulation alongside a physical prototype testbed, however there exists differences between both systems. The simulation uses linear-quadratic regulator (LQR) control on all states of the system to control the quadcopter position and attitude. The testbed utilizes an outer- and inner-loop proportional-integral-derivative (PID) controller to manage the attitude of the pendulum and quadcopter respectively. These differences were amended by implementing PID control in the simulation and then the accuracy of the simulation was verified using flight data from the testbed. Once the accuracy of the simulation is confirmed, it can be used to develop more advanced control algorithms for testing on the prototype. Comparison of simulation results with flight data showed that the accuracy of the simulation was within reason. The simulation was then used to develop a linear-quadratic regulator outer-loop controller for the inverted pendulum.