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Workspace Variation of a Hexapod Machine Tool



J Conti, C Clinton, Li Zhang, Albert J. Wavering


A method is presented to evaluate the workspace variation of a Stewart platform based machine tool. Three sets of constraints, covering strut lengths, platform and base spherical joint angles, and strut collisions, are formulated using inverse kinematics. Recognizing the need to vary the platform orientation during machining, an algorithm to efficiently calculate the workspace is developed. Computer implementation provides a powerful tool to study the dynamic variation of the workspace as the spindle platform changes orientation. A case study is presented on the workspace variation of a prototype hexapod machine tool as a function of platform orientation. The results demonstrate the shift in size and location of the workspace as the platform orientation changes. The workspace analysis tools presented can be used to maximize the versatility of Stewart platform based machines and avoid violation of workspace constraint conditions.
NIST Interagency/Internal Report (NISTIR) - 6135
Report Number


Hexapod, forward kinematics, hexapod, inverse kinematics, Stewart Platform, workspace


Conti, J. , Clinton, C. , Zhang, L. and Wavering, A. (1998), Workspace Variation of a Hexapod Machine Tool, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 12, 2024)


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Created February 28, 1998, Updated October 12, 2021