Direct kinematics of parallel manipulators usually is a complicated problem which in general does not have a close form solution. It is well known that parallel manipulators admit generally several direct kinematic solutions for a given set of input joint values. Direct kinematic computation is an essential part in control and simulation. Bezout’s elimination method is a way to obtain all solutions. Using this method direct kinematics solutions will be obtained as roots of a polynomial. However, obtaining the one desired solution has been a challenging problem. It is shown that workspace of a parallel manipulator could be categorized to special regions named basic regions. Each region contains one of the polynomial’s solutions. Using workspace categorization, a method is proposed to determine the desired solution from the polynomial set solutions. The study is illustrated all along the paper with a 3-RRR planar parallel manipulator. Finally some future works are suggested where workspace categorization may be combined with available methods in solving direct kinematics.

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