Mechanism with two degrees of freedom on the base of closed kinematics chain for reproduction with required precision of wide class of planar curves

摘要

The increase of precision of the gripper positioning is one of the main problem of manipulator devices designing. The mechanism based on the closed chains permit to increase the precision of positioning. But in this case the most rigid requirements to dimensions precision of kinematics chain elements are presented. In this report the problem of reproduction of wide class of planar curves in servicing zone with adequate accuracy is discussed. One of the possible decisions is utilization of the coupler point of four hinge closed kinematics chain with variable length of crank. The following tasks are viewed. 1. The conditions of existence and constraints of reproduction of planar curves class are assigned and conditions of positioning of the coupler point are defined. 2. The mechanism dimensions and limits of crank change dimensions for given class are determined. 3. The laws for one of the possible control curves are found. 4. For fixed conditions of positioning the allowable deviations (tolerance) of mechanism dimensions and accuracy of control actions reproduction are determined.