Research On Mathematical Modeling And Accuracy Performance Of Parallel Type Six-axis Accelerometer

In order to sensitively, accurately, and comprehensively sense the movement changes of anobject which has a three-dimensional space movement, it is obvious that the measurement of six-axisacceleration of the object has a more universal adaptability, as a result, six-axis accelerometers comeinto being. Currently, researches on six-axis accelerometers still remain in the exploratory stage, themain technical difficulties are the large amount of input and output information, as well as theovercoupled nonlinear vibration differential equations of the system, which make it difficult todecouple the six acceleration components timely, accurately and stably.Through a comprehensive study on the technical difficulties and research trends of six-axisaccelerometers at home and abroad, this paper selected the elastomer-strain type six-axisaccelerometers based on parallel mechanism as the study object, where the improvement ofcontradiction between structural complexities and decoupling difficulties acts as a turning point, thetopology configuration design, mathematical modeling and accuracy performance of parallel typesix–axis accelerometer are conducted. Four parallel topology configurations, corresponding to6,7,8and9UPS limbs parallel structure, were proposed as the elastic body of parallel type six-axisaccelerometer, which have6DOF and a closed-form solution of the forward kinematics. A decouplingalgorithm of six acceleration components is derived based on the geometric properties of thetetrahedron, KANE’s dynamics and numerical algorithm, which has a high calculation efficiency, andcan meet real-time decoupling of six-axis acceleration. The size effect error of geometric model inaccelerometer system was analyzed and compensated from the aspects of mechanical design andmathematical modeling, respectively, including the design of integrated multiple compound hingesand the derivation of two-level compensation algorithms of size effect error, in addition, the errorsensitivity of configuration to size effect was researched. Considering the geometric nonlineardeformation of widgets of elastic-stain type six-axis accelerometer in mechanical vibration, apseudo-rigid-body model algorithm was established in combination with pseudo-rigid-body modelmethod, energy method and least square method, which makes a theoretical foundation onmathematical modeling in reflecting the real flexible deformation characteristics of parallelmechanism. Finally, a reconfigurable prototype was designed and manufactured, whose relateddecoupling parameters were identified, and then, the correctness of the established mathematicalmodels were verified through concrete experiments. Meanwhile, the design of reconfigurable prototype will help to research on the structural optimization and influences analysis of configurationson the performance of parallel type six-axis accelerometers.In this paper, the mathematical modeling and accuracy performance are selected as the main line.The decoupling algorithm, calculation efficiency, size effect, flexible deformation, and principleaccuracy, etc. were explored, all these works promote the practical use of parallel type six-axisaccelerometer.