KINEMATIC AND STATIC CHARACTERISTICS OF IN-PARALLEL ACTUATED MANIPULATORS AT SINGULAR POINTS AND IN THEIR NEIGHBORHOOD

In the process of mechanism design and trajectory planning of in-paral lel actuated manipulators, it is necessary to know the locations of al l singular points in the working space. We propose a new method for nu merically locating the singular points of in-parallel actuated manipul ators based on the pressure angle. A singular-point curve is defined a s a set of singular points. Kinematic and static characteristics at si ngular points are analyzed by pressure angles and instantaneous screw axes. Singular points of the Stewart Platform are investigated using t he proposed method. The neighborhood of singular points is determined from output error, isotropy of output force and driving force, and thu s the practical working space is defined.