Effect of Actuation Schemes on Performance of Industrial Manipulators

摘要

This paper presents the effect of actuation schemes on manipulator Jacobin, kinematics isotropy, manipulability and Global condition index (GCI) of non redundant serial manipulators. An actuation scheme is the relocation of set of actuators at various joints of the manipulators in order to drive all the joints with appropriate transmission ratios using such as pulleys, gears and other mechanical linkages. These actuation schemes can be used to optimize the performance of serial manipulators in a six dimensional task space. The effect of transmission ratio on the manipulability, condition number, GCI and on the velocity ellipsoid is studied, which could be viewed as a position error amplification ratio. The transmission ratios and drive mechanisms are selected in order to obtain good kinematics characteristics. The effect of actuation schemes on manipulator performance is studied for the planar manipulators and also for the spatial manipulators, four axes SCARA and six axes STANFORD manipulators as an example. The performance optimization by changing the link lengths, link offset for each joint variable have done for these manipulators. The constraint on each joint variable is established. The choice of actuation scheme influence the size, shape and direction of the velocity ellipsoid in the manipulator task space, for that choice of actuation scheme can be used as a design variable to improve kinematics performance.