The design and manufacture of a low cost, six axis, industrial robot

Abstract

The aim of the work presented in this thesis is to investigate the feasibility of producing a low cost, 6 axis, Industrial Robot. The formulation of a design specification based on market trends is shown, and used as a starting point for formal design analysis. A robot conceptual design based on two, series coupled, triangular link mechanisms was devised, following a detailed analysis of various kinematic mechanisms. The purpose of the mechanisms analysis was to find a low cost, inherently stiff, means of driving the robot main axes; in particular, the shoulder and elbow joints. By adopting the novel concept of a hand and wrist mechanism, a "true 3 axes" wrist was devised. A unique feature of this is that the roll, pitch and yaw axes form an orthogonal set with the origin at the wrist point. Although emphasis is placed on the robot mechanical design, a Servo amplifier system, suitable for driving all 6 axes of the robot is presented, and recommendations for a position control system are given. Finally, costs relating to the robot mechanical system, Servo amplifier system and Position control system were investigated. The variation in cost with robot volume is shown for each of the 3 systems. This indicates that a manufacturing cost of E9000 per robot can be achieved providing at least 150 robots are produced. The following papers have been published by the author in connection with this work: (i) The Development and Design of a Low Cost Assembly Robot, Proceedings of the 7th B.R.A. Annual Conference, May 1984. pp 171-182. (ii) Overview of Robotic Manufacture Worldwide, Seminar "Exploiting robot in arc welding fabrication", The Welding Institute, Cambridge, Nov. 1984. pp 1-7