Secure Observer-based Motion Control based on Controller Encryption
Kaoru Teranishi, Masahiro Kusaka, Naoki Shimada, Jun Ueda, Kiminao Kogiso · 2019
Disturbance observer-based motion control, one of effective schemes for force control and uncertainty compensation has been widely used in industrial systems such as manipulators and servo systems. Despite its effectiveness reported in the literature, security measures applicable to industrial equipment and motion control systems have not yet been established in comparison to those to information equipment. A lack of cybersecurity measures may result in critical incidents in the future. This study proposes a method to enhance the cybersecurity of an integral-type servo controller with a full-order state observer, or disturbance observer, for an industrial motion control system based on controller encryption. Feasibility of the controller encryption method was confirmed through position servo control experiments with a feed drive testbed. Influences on computational latency for real-time control were examined by varying the size of the key used for encryption. Performance degradation of the proposed encrypted control systems was millimeter order, and thus the controller encryption method can be applied as a security measure in motion control systems.