Abstract. Among parallel robots, spherical robots occupy an important place.
Most applications of spherical manipulators can be found in orienting
devices, such as camera orienting and medical instrument alignment. A
spherical parallel robot is, in general, made up of the base platform and the moving platform. This mobile platform and base are connected by three equally spaced legs, each consisting of revolute joints only. The axes of all joints intersect at a common point, which is called the center of rotation. The motion of the moving platform is confined on the surface of a sphere centered at the rotation center. A spherical parallel robot provides 3 degrees of freedom of pure rotations. These robots have been the subject of many papers dealing with the structure, the problems of position and
velocity, workspace modeling, singularity analysis, and some problems with
the dynamic analysis. However, not all the important problems have been
solved. These concern the problem of accuracy. This paper presents
accuracy of the spherical parallel. In the considered spherical manipulator, each leg consists of five kinematic pairs. The kinematic accuracy is determined on the kinematic problem. The dynamic accuracy is estimated on the equation of motion. Examples of solving the problem of determining the positioning error of the output level are presented.