Investigations of a compliant manipulator implementing micro-scale 2D displacements

Abstract

The paper summarises the results of investigations of a 2D compliant manipulator implementing two independent orthogonal linear displacements. The device is comprised of a steel element with monolithic design, its motion induced by two independent screw-drive actuators. Underpinning the monolithic system design is the classical planar lever mechanism model. Macro-scale motions of the drives are reduced by two variators (variable displacement transmission units) effecting seamless control of displacement limitation via the settings of two additional independent screw-drive actuators. The resultant of thus reduced independent displacements is obtained at one vertex of the square platform where an end-effector or gripper may be mounted. A transformation matrix is formulated containing kinematic and coupling ratios. FEM calculations were performed to estimate the stress levels in flexure hinges in the neighbourhood of the motion stages. The manipulator workspace where elastic stresses will arise in flexure hinges has been determined. Tests conducted with the use of a microscope have validated the predicted motion properties of the monolithic system.