Study On Key Techniques Of Earthquake Simulator With 3-2-1 Structure Parallel Mechanism

The earthquake simulator is one of the most important test equipment in the research of the earthquake engineering. The earthquake simulator with parallel structure shows several advantages, such as, higher stiffness, better symmetry, higher velocity, better dynamics and compact structure. In this dissertation, a new redundant activate parallel mechanism with 3-2-1 structure applied in the earthquake simulator is presented and studied in many fields, such as structure, kinematics, statics, workspace, physical model of the solution space and so on.1. Drive the inverse position equation. Based on the differentiation to the inverse position equation, we get the analytic expression of the inverse jacobian matrix' J-1', the expression is the foundation of the research in many performance indexes.2. Based on the inverse position equation and the jacobian matrix, the solution of direct position is obtained through the numerical iteration method.3. The statics equation and the force/moment transmission matrix 'G' are obtained, then base on the principle of virtual work, the relationship between the two matrix 'G' and 'J' is obtained.4. The physical model of the solution space are established and that grounds the foundation for the optimum design.5. Detailed analysis in workspace is made by two means: numerical and analytic method. The conclusion is: The sectional view of reachable workspace reach its maximum area when z = 860, The sectional view of dexterous workspace reach its maximum area when z = 807.6. Based on the physical model of the solution space, analyze the relationship between the workspace and the parameters of the manipulator, the optimal value of the parameters is obtained.