Optimization Design And Dynamic Characteristics Of 3-DOF Parallel Shaking Table

In the application process, many devices are often faced with multi-dimensional vibration in different bands and amplitude, especially important components used in military, medical, aerospace and other fields, and these devices must take rigorous vibratory test before delivery. Vibration table is the equipment of generating vibration which could simulate the vibration environment, plays an important role in the vibration experiments. At present, the domestic research on multi-dimensional vibration mainly concentrates in large and heavy earthquake simulation platform, this kind of simulation platforms have strong bearing capacity and wide working frequency band, they mainly used for the experiment of the reliability for Large structural parts, but their cost is high and it is difficult to ensure accuracy, therefore their applications have certain limitation. In this paper, a 3-DOF parallel vibration table should be optimized the design and analyzed vibration, with the aim to design small electric vibration table, based on the parallel mechanism, and the result should be verified.Firstly, synthesize several branches of three translational agency contains closed-loop for the performance requirements for the work of the vibration table, and select 3-P(4S) structure as the ultimate embodiment of the vibration table. The kinematics and dynamics analysis of the mechanism, make its mapping matrix of the velocity and the acceleration and the dynamic equation gotten, and the result was simulated and verified by the application of Adams.Secondly, the evaluation index of the dynamics, stiffness, the sensitivity was established for evaluating the comprehensive performance of the mechanism, and take this as the basis of the objective function for mechanism’s global optimization. In addition, the genetic algorithm of the Matlab toolbox was applied for the mechanism’s optimization, considering the mechanism’s various properties, and the final optimized size should be gotten.Again, the mechanism’s vibration model was established, the natural frequency and vibration characteristic of the vibration table was analyzed, the calculation results was simulated and verified by the application of the Adams software; the impact of the mechanism position’s change for the natural frequency and the sensitivity of the structural parameter for natural frequency were analyzed. The vibration responses’ model with damping and without damping was established, and the calculation results were simulated and verified by using the Matlab’s simulink module and Adams software. In addition, the results for the time-domain of pulse excitation was taken discrete Fourier transformed, mechanism’s spectrum curve was gotten.Finally, applying the transient excitation method, the dynamic stiffness of the linear motor servo was determined, the greatest amount of deformation under the weight of each group were obtained by applying different weight loads, and obtained the motor’s dynamic stiffness by drawing curves. In addition, it determines natural frequency value under each mode to apply modal tests by knocking, the result should be verified compared with the previous theoretical analysis.