An Integrated, Modular Simulation System for Education ... - Cal Poly

Key Features of SimulationsStability and controls engineers use models of varying complexity to analyze anddesign control systems for aircraft. These range from simple first and second orderdifferential equation models of the rotational and linear dynamics of only the primaryaxis dynamics, to complex state space models, to full non linear equations of motionmodels. To verify the 6 DOF non linear model, two state space models were created andcompared to the dynamics of the 6 DOF model. Finally a transfer function model wascreated using the literal factors approximations for natural frequency and damping ratiodemonstrated in [Ref. 33]. The transfer functions were built up using the Euler block toallow the model to be flown. The three models demonstrate the same aircraft modeled atthree levels of complexity and allow the models to be flown side by side to compare thedynamics produced by each set of equations. The models will be described from the mostsimple (transfer function) to the most complex (6 DOF) rather than the order they werecreated.Usually transfer function models are used for batch simulation to obtain timehistories or frequency domain plots of the motions to check individual responses of aaircraft configuration to a control input. The models are used to get a feel for the basicdynamics of an aircraft during the earliest stages of design. Flying the equations providea connection between the parameters obtained from the equations and how the aircraftresponse is affected by changes to the parameters.State space and full nonlinear simulations are usually done later in thedevelopment of aircraft due to the overhead of coding the equations of motion andcontrol systems. Autocoding software allow models at any stage in the development of anaircraft to be created and flown .48