Design and implementation of position estimator algorithm on double flexural manipulator

Abstract

Traditional mechanical systems (e.g. rigid mechanisms which use links, gears, chains, etc.) have restricted resolution and repeatability due to certain properties like friction and backlash. A mechanism is a mechanical system which provides relative displacement between rigid links by using certain joints. Commonly available joints are rolling, sliding, pin, hinges, liquid joints etc. These types of joints exhibit nonlinear frictional behaviour due to which it becomes difficult to control micro and nano positioning in high precision mechanisms. To accomplish high degree of resolution and precision, disadvantages such as backlash, friction in the mechanism needs to be eliminated. These mechanical joints are substituted by flexible components like flexural beams and hinges that provide benefits such as smooth and frictionless displacement. A single DOF flexural stage is developed by using basic building elements like flexural hinges and beams so that they offer negligible resistance to motion in targeted direction and maximum resistance in orthogonal which is also known as parasitic error. Double Flexural Mechanism (DFM) is a beam type of building element that provides analytically zero parasitic error displacement with imperceptible rotation of displacement stage. This research article presents design and development of DFM, its mechatronic integration with dSPACE DS1104 R&D Controller and its experimental validation and system identification. Static and dynamic experimentation was performed and various performance characteristics like stiffness, natural frequency and damping factor are determined experimentally. Further, a novel position estimator algorithm is designed and implemented on the mechanism that eliminates the need of high cost sensor and yields as accuracy of 25 microns at a speed of 6.4 mm/s.