ARNOLD TUSTIN was an electrical engineer and a pioneer in the theory of servo-mechanisms.
Born in 1899, Tustin joined the Parsons Company in 1914 as an apprentice and entered Armstrong College (later part of Newcastle University) in 1916. After service with the Royal Engineers he completed a degree course in science, followed by a master's degree, and joined Metropolitan-Vickers in 1922. He spent two years in Moscow in the early 1930s, advising on equipment sold by Metro-Vick to the Soviet Union. A book on the design of electric motors, written during his stay in Moscow, was translated into Russian.
During the Second World War, and following a period as assistant chief engineer with Metro-Vick, Tustin made a significant contribution to the efficiency of the armed forces by working on control engineering projects in relation to automatic gun-laying and gyroscopic stabilisation, particularly the application of servo-mechanisms to tanks and naval guns. His work in this area gave him a deep understanding of the significance of the principles of feedback, as the basis of all servo-mechanisms, which he expounded in a classic article in Scientific American, in 1952.
Tustin became Professor of Electrical Engineering, and Head of Department, at Birmingham University in 1948, was appointed Visiting Professor at the Massachusetts Institute of Technology, and occupied the chair of electrical engineering at Imperial College, London, from 1955 to 1964. During the 1950s he produced a wide range of papers on aspects of automatic control systems which contributed to the foundations of the growing science of systems engineering.
His interests were wide, ranging beyond engineering and embracing psychology, philosophy and economics; and he urged acceptance of the concept of engineers becoming involved in intellectual partnerships with other disciplines. To this end he published in 1953 The Mechanism of Economic Systems, a unique view of Keynesian economic theory using analogies based on feedback loops within control mechanisms. His breadth of vision was reflected in his chairing Imperial College's General Studies Committee and his participation in its Humanities programme. In 1968 he received the honorary degree of Doctor of Technology from Bradford University.
Arnold Tustin worked with vigour almost to the end of his life in spite of failing vision and hearing. During his final months he completed a text which set out his views on the interrelationships of psychology and evolution. To this task he brought the uncompromising intellectual honesty which had characterised his life's journey.
He is survived by his wife, Frances, an international authority on autism, whom he married in 1948. They constituted a happy, gifted partnership from which each derived strength and support.