Improved Stewart platform state estimation using inertial and actuator position measurements

Abstract

Accurate and reliable estimation of the kinematic state of a six degrees-of-freedom Stewart platform is a problem of interest in various engineering disciplines. Particularly so in the area of flight simulation, where the Stewart platform is in widespread use for the generation of motion similar to that experienced in actual flight. Accurate measurements of Stewart platform kinematic states are crucial for the application of advanced motion control algorithms and are highly valued in quantitative assessments of simulator motion fidelity. In the current work, a novel method for the reconstruction of the kinematic state of a Stewart platform is proposed. This method relies on an Unscented Kalman Filter (UKF) for a tight coupling of on-platform inertial sensors with measurements of the six actuator positions. The proposed algorithm is shown to be superior to conventional iterative methods in two main areas. First, more accurate estimates of motion platform velocity are obtained and, second, the algorithm is robust to inherent measurement uncertainties like noise and bias. The results were validated on the SIMONA Research Simulator (SRS) at TU Delft. To this end, an efficient implementation of the algorithm was driven, in real time, by actual sensor measurements from two representative motion profiles.

Incremental Nonlinear Dynamic Inversion Control for Hydraulic Hexapod Flight Simulator Motion Systems

“…The motion profile of a real-world experiment on the SRS (Miletović et al, 2016) is chosen as the reference trajectory of the motion system. This profile moves the upper platform periodically along a circular path in the horizontal plane with a radius of 0.5 meters and a period of five seconds after a brief lead-in period (Huang et al, 2016b).…”

Long-Stroke Hydraulic Robot Motion Control With Incremental Nonlinear Dynamic Inversion

“…A more aggressive asymmetrical motion used for a previous state estimation experiment [46] is used to further evaluate the proposed controller, with more excitation of all nonlinear dynamics and kinematics. In this motion, the upper platform traces a 0.5 m radius circular path in the horizontal plane with a period of five seconds.…”

Robust trajectory tracking control of a 6-DOF robotic crusher based on dynamic compensation

“…Meanwhile, parallel robots are widely used in aviation, shipping, and entertainment facilities because of their high rigidity, large payload, and high flexibility. [11][12][13] A 6-DOF robotic crusher is developed by combining the crushing chamber of cone crusher with the intelligence of parallel robot. 14 Trajectory tracking control is a difficult issue for the 6-DOF robotic crusher due to its complex kinematic and dynamic modeling.…”