Tomizuka’s research covers control theory and its applications to various mechanical systems. A balance between theory and laboratory work is emphasized. The trend in mechanical system design is to replace mechanical complexity with electronics and computers (real time controllers) in order to gain high performance, reliability and flexibility. A number of control methodologies relevant to mechanical systems are under investigation in his research group: they include optimal control, preview control, adaptive control, and nonlinear robust control. Since these control methodologies are implemented on computers, the discrete time (digital) aspect is emphasized in the development of theory. Actual mechanical systems currently under study include direct drive robot arms, a machining center, x-y motion control tables, computer disk file systems and automotive vehicles.