Precision Apparatus With Non-rigid, Imprecise Structure, And Method For Operating Same

Abstract

An apparatus which allows one to maintain precision placement of a manipulator which undergoes repeated controlled motions or trajectories is provided. The structure of the apparatus is compliant such that the manipulator may be displaced by forces applied to the mechanical structure. This compliance is due to a lack of precision in the fabrication of the component parts of the machine, and to a lack of rigidity due to a lightweight design. This displacement is of a greater magnitude than the precision positioning tolerance of the apparatus. Consequently, the manipulator may then be displaced outside of the positioning tolerance due to applied forces. However, it is a characteristic of the present invention, that despite the compliance of the mechanical structure of the apparatus, the positioning tolerance will be maintained. The controlled motion is accomplished by the generation of control signals by computer software running on a computer control system. The control software enables the system to run at much greater speeds while not exciting unwanted movement or vibration in the compliant mechanical structure.