Abstract: This paper outlines the design and development of a 5 1/2 degree-of-freedom ro-botic arm in the Department of Mechanical and Marine Engineering of the HongKong Polytechnic.The design and construction of the arm itself,the associatedmicroprocessor-based control system and interfaces together with the writing ofassembly language software are described.A proportional-plus-integral controller wasadopted for the feedback control of thearm movement.Closed-loop controller set-tings of the first three axes obtained from the experimental tests are also given inthis paper.