Two Mitigation Strategies for Motion System Limits in Driving and Flight Simulators

Limited workspace is a challenge for all motion-based simulators, whether they are large excursion systems like the National Advanced Driving Simulator or smaller simulators utilizing only Stewart Platforms. Two approaches for addressing this challenge are nonlinear washout scaling and software displacement limiting. This paper presents new algorithms developed for these approaches. The nonlinear scaling method uses the cubic Hermite interpolation polynomial to smooth the corner in the scaled output at the limit. A software displacement limiting method that generates control signals in the table frame of reference is introduced. As a result, unwanted acceleration artifacts caused by unbalanced limiting of actuators are avoided. The methods are described, and offline simulation results using the new displacement limiting method are presented.