Elastodynamics of an overconstrained 8-SS platform for touchdown impact force measurement

Abstract

Passive overconstrained parallel mechanism has many advantages due to extra constraints to the platform. When applied to the force sensor field, it can increase the capability, stiffness and dynamic response of the sensor. In this study, an overconstrained [Formula: see text] platform is presented to measure the multi-dimensional landing impact force. Screw theory is used to obtain the concentrated inertia force. Then, by adding the inertial force into the VJM (Virtual Joint Method) stiffness model, the static analysis is extended to elastodynamics analysis. Natural frequency and modal are derived from the elastodynamics equation and show well agreement with the FEA result in Abaqus. Theoretical force measurement equation is deduced. The FEA simulation result proves the effectiveness of the theoretical equation. Experiments are also conducted to verify the feasibility of the platform.