| The regeneration of suspension vibration energy is an effective means of energy saving and emission reduction,and also one of the key research objects of suspension technology.Aiming at the problems of high fuel consumption of trucks,low efficiency,high cost and poor reliability of suspension motion conversion mechanism,a two-degree-of-freedom multi-link parallel mechanism was proposed to cooperate with energy-feeding motor to realize energy recovery and utilization.In this paper,the geometric characteristics,fractal principle,kinematics,statics and dynamics of a two-degree-of-freedom six-bar parallel mechanism were analyzed.Firstly,a two-degree-of-freedom six-link parallel mechanism model was established and its degree-of-freedom analysis was carried out by using the theory of constrained helix.Secondly,in Matlab/Simulink software,the effectiveness of the energy feedback active suspension was verified by simulation analysis.According to the transformation formula of position and attitude coordinates and Newton-Raphson iteration method,the mathematical models of inverse and forward position solutions of the parallel mechanism were established.The velocity mathematical model was established by the first-order influence coefficient method and the acceleration mathematical model was established by the second-order influence coefficient method.The expression of rotation period of parallel mechanism was obtained by space projection method.Then,according to the principle of fractal mathematics,the geometric problems of multi rod,multi angle and multi edge structure are studied,and the problems of k value and anchor point ofi i kA A(10)in the fractal principle of two degree of freedom parallel mechanism are solved.Through the research of three k value related problems,the mathematical law of point-chord-circle was obtained.Finally,the validity and validity of the two-degree-of-freedom six-link parallel mechanism model are verified by numerical examples and simulation analysis.Based on the kinematic analysis of parallel mechanism and the principle of virtual work,the static equilibrium equation of parallel mechanism was established.Theconstraint force equation of spherical hinge pair between upper and lower platforms and connecting rods was obtained by using the traditional dismantling method and taking branching rods and central active rods as the research objects.By using the Lagrangian equation method,a dynamic model of suspension system with two degrees of freedom six link parallel mechanism was established.The dynamic simulation analysis of the mechanism was carried out by ADAMS finite element simulation software,and the validity of the mechanism was verified.Then,the dynamic simulation analysis of five angle,six prism and seven angle parallel mechanism was carried out respectively.Through the simulation analysis and comparison,the results show that the multi rod,multi angle and multi edge mechanism has the advantages of large structural rigidity,fast response and good motion performance,which provides a theoretical basis for the follow-up study of energy feedback suspension. |
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