Parallel Kinematics-Based Mechanism and Its Industrial Application in CNC Machine Tool Development

Abstract

Parallel Kinematics Manipulator (PKM) is a closed-loop mechanism having certain inherent advantages over serial ones in terms of accuracy, stiffness, acceleration speed, and increased workload. PKM with six DOF is typically referred to as hexapod. It is also known as the Stewart–Gough platform. In PKM, all the links are connected to the ground and the moving platform at the same time. A Stewart platform is a six-degree-of-freedom parallel manipulator robot with six prismatic joints that are used to define the position and orientation of the moving platform. The base plate and end effector are connected by using serial chains (called limbs or legs). PKM has various industrial applications such as flight simulation systems, manufacturing, medical applications, and precision laser cutting. This work presents the development of a PKM-based computer numerical control (CNC) machine tool and its useful applications for the small-scale industry, research laboratories, or tool rooms. The CNC machine tool structures are generally based on a Serial Kinematic Manipulator (SKM). However, SKM has some limitations like low stiffness, low strength-to-weight ratio, and large workspace and requires comparatively bulky structures. Therefore, a novel concept is being developed to employ parallel kinematics for the development of CNC-based machine tools. This paper presents the design and development of an algorithm to compute the three-dimensional workspace of the PKM-based CNC configuration Monte Carlo method. A MATLAB-based computer program has been written to compute the space volumes using inverse kinematic analysis. The developed algorithm and the computed volumes will be helpful to design and fabricate the proposed low-cost and simple CNC machine configuration.