Journal of Mechanical Science and Technology 31 (9) (2017) 4459~4470 www.springerlink.com/content/1738-494x(Print)/1976-3824(Online) DOI 10.1007/s12206-017-0846-1 Studies on Stewart platform manipulator: A review † Mohd Furqan 1,* , Mohd Suhaib 1 and Nazeer Ahmad 2 1 Department of Mechanical Engineering, Jamia Millia Islamia University, New Delhi, India 2 Scientist/Engineer SE, ISRO Satellite Centre, Bangalore, India (Manuscript Received July 31, 2016; Revised December 13, 2016; Accepted May 6, 2017) ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Abstract This paper presents a compilation of previous studies on the Stewart platform, which is a class of six degree of freedom parallel ma- nipulators. The abstraction of a parallel manipulator is appropriated for the entire class of it. The paper focuses on the studies in the dif- ferent fields which are closely checked to determine the direction of research and identify the solved problem areas. A significant investi- gation has been presented to discuss the existing methods for the analysis of the Stewart platform manipulator due to their unique appli- cations. Studies on analysis and design of the Stewart platform manipulator using flexible joints are included. Modeling and analysis of parallel manipulators by Matlab SimMechanics environment are also highlighted. Keywords: Flexible joint; Parallel manipulator; Robot; Stewart platform ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 1. Introduction The Stewart platform is a six-legged parallel manipulator. The need of more accurate motion of mechanical structures has been increasing in recent years. Parallel manipulators have high stiffness and have gained popularity due to accurate posi- tioning capability. Their high level design produces superior load capacity and positioning precision over the serial ones. The potential applications of parallel manipulators include both terrestrial and space applications, including satellite an- tennas, telescope positioning systems and pointing devices [1]. The most important technology control and vibration isolation between the precision instrument and disturbance source have been applied to many space applications like space interfer- ometry, spacecraft laser communications and other precision spacecraft. The Stewart platform is a locating system that includes three major parts: top or moving plate, base or fixed plate, and six identical stretchable legs. The ends of all the legs are attached to the moving and fixed plates by spherical, universal or flexible joints. It is one of the most accepted par- allel manipulators known as the Stewart platform. This mechanism was first suggested by Gough in 1949 as a univer- sal tire-testing machine [2], which was re-discovered and pre- sented to academia in 1965 by Stewart as a flight simulator [3]. Gough was the first to realize the benefits of this mechanism and research in this area was carried out after Stewart’s Paper. Therefore, the platform is generally called a Stewart platform. Bhaskar and Mruthyunjaya [4] presented the literature avail- able on Stewart platform till 1998. A brief introduction is given in Sec. 1. The analysis and characterization of the singularities and approaches towards workspace analysis is described in Sec. 2. Determination of position, orientation of the platform and kinematics of the Stewart platform is reviewed in Sec. 3. For the dynamic analysis of the parallel manipulators various methods have been implemented, but the Newton-Euler and Lagrange meth- ods being the most popular ones and are discussed in Sec. 4. Control and vibration isolation strategy for the Stewart plat- form are summarized in Sec. 5. Finite element method is nec- essary for the detailed design of the Stewart platform system due to the complicated geometry of the Stewart platform and the necessity of modeling the joints stiffness precisely, which is described in Sec. 6. Matlab SimMechanics environment for block diagram modeling and simulation of Stewart platform is reviewed in Sec. 7. The literature on flexible joints and Stew- art platform with flexible joints is discussed in Sec. 8. Finally, in Sec. 9, the review is summarized and concluded with some future scope. 2. Singularities and workspace A parallel manipulator mechanism may attain or release one or more degree of freedom at a singular point. Many research- ers have studied singularities in terms of statics [5]. The paral- lel manipulators cannot resist external forces and torques in definite directions due to some constraints and these con- straints have to be determined. The architectures limit the * Corresponding author. Tel.: +91 9457194742 E-mail address: mfurqanamu2006@gmail.com † Recommended by Associate Editor Kyoungchul Kong © KSME & Springer 2017