Spatial accuracy analysis of multi-axes fixed and floating base robot by comparing mechanisms

Abstract The end-effector position depends on various factors like joint angles, joint velocity, and base position. The performance features like positional accuracy, structural and mechanical errors mainly rely on the nature of input provided. Moreover, positional accuracy forms an important parameter for kinematic analysis of robot motion and performance evaluation. This article draws a comparison between fixed base and floating base robots, highlighting the distinct factors affecting their positional accuracy. For fixed base robots, positional accuracy is primarily influenced by mechanical issues such as joint clearance and drive backlash, whereas, free-floating base space robots experience these inaccuracies due to the movement of the floating base and the coupling effects between base and manipulator. To analyse these differences, six degrees of freedom manipulator is modelled using the Newton-Euler method for both fixed and floating bases, in order to evaluate the positional accuracy of the end-effector within the workspace. The robotic model is moving in the X-Y plane. This analysis is particularly significant for applications requiring precise operations, such as in industrial automation, space exploration, and medical robotics. The end-effector positional accuracy of the fixed manipulator is 3% higher than that of the floating base robot, with 0.02 m more dexterity.