Introduction

The potential use of robots has expanded manifolds. Since the first modern industrial robot in 1960’s, robots are finding applications in various manufacturing sectors, warehouse management, telesurgery, rehabilitative task, hazardous environment, manoeuvring, and surveillance in an unknown environment. The International Federation of Robotics defines an industrial robot as “automatically controlled, reprogrammable, multipurpose manipulators programmable in three or more axes”. Typical industrial robots are large and bulky automated machines. They are also inexpensive compared to those without any integrated or embedded sensors, like a joint torque sensor that enables the robot to be sensitive to external forces which makes it safer to use. Industrial robots have good repeatability but poor accuracy, and are position controlled brute machines that apply full force to reach the commanded pose, i.e., position and orientation. It results in several challenges during an manipulation and assembly task and it becomes more challenging during a precision based assembly where the mating objects have lesser clearance in comparison to robot positioning accuracy.