The Force And Virtual Simulation Analysis Of Passive Over-constrainedparallel Mechanism With Gravity

As a special mechanism, over-constraint parallel mechanism has all the advantages of parallel institutions, and in many cases plays an important role. However, therer are statically indeterminate problem in this analysis, and it is difficuld to calculate the final result.In the present,studies on this area is not much,and almost aim at specific mechanism. As a result of the complexity of analysis, the reserch on this problem has to be simplified, so they regard the gravity as the second factor, but this may reduce the accuracy. Therefore, this paper is considering the premise of elastic deformation and gravity in the analysis of passive restraint mechanism; the main contents include the following aspects:Firstly, on the base of the method of not considering the gravity, we research the way to analysize the over-constrained mechanism under the action of gravity, and compara the analysis result of considering and not considering the gravity.Secondly, through the relationship of the branch driving screw and the kinematic pair, derived a full Jacobi matrix of 3PRRR in the form of 6 ?6, according the Dummy joint method to solve the velocity and acceleration of each branch to obtain Hessian matrix, then combined with the virtual work principle to establish the dynamic model.Then, use ANSYS and Adams software to build rigid-flexible coupling model of 3PRRR, and set the gravity property and other parameters in Adams, compare the result of the measuring and the simulation.Finally, we propose a method of how to bond strain gauge which can measure the dimensional deformation, and derive its mathematical model.