| A laser measuring platform(6-RUS parallel mechanism) is proposed in this paper. It might be the better candidates to realize laser measurement with high precision due to its advantages of large working range, high precision and low movement inertia.This paper describes the tructural characteristics and freedom analysis of the laser measuring platform. Position analysis is then carry out, which can obtain the inverse position. Based on a new algebraic elimination method for the forward kinematics analysis of the general 6-6 platform parallel mechanism, forward displacement analysis are presented. Furthermore, 3D-workspace can be drawn on the fundation of constraint condition and inverse position, which approximately shows the working range of terminal reference point.Influence coefficient theory is discussed, and kinematics analysis is then carry out.Velocity jacobian matrix that reflects transitive relation of velocity can be figured out with derivation method respecting laser measuring platform. Besides, the first-order effect coefficient matrixes and the second-order effect coefficient matrixes are derived on the basis of influence coefficient theory. By imposing velocity function and acceleration function, change curves of the angular velocity and angular acceleration are obtained relied on Matlab.Disassembled rod method that can get whole statics solution is used to analyze the force condition of the moving platform, static platform, active rods and follower rods.Force Jacobian matrix is established by vector method and principle of virtual work.Finally, the evaluation indexs of static performance are defined with force Jacobian matrix mentioned above. The experimental results have indicated that force Jacobian matrix can reveal the relationship between structural parameters and the evaluation indexs of static performance. Moreover, the parallel mechanism this paper proposed theoretically have better statics comprehensive performance. |
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