Motion-control techniques of today and tomorrow: a review and discussion of the challenges of controlled motion

Abstract

Motion control technologies are in core of multiple mechatronic products and applications. Wherever an actuated motion takes place in machines and components, either position or force setting (correspondingly trajectory tracking), or even a combination of both, are demanded from the control system. In high-performance mechatronic systems including micro-and/or nano-scale motion (such as data storage devices, machine tools, manufacturing tools for electronics components, and industrial robots), the required specifications in motion performance, e.g., response/settling time and trajectory/settling accuracy, should be sufficiently achieved [1]. From an industrial perspective, the most common design objective for advanced motion control is to achieve a good tracking/following performance in the presence of disturbances and modeling issues -nominal plant and performance specifications [2]. While motion control, as an applied field of control theory, established itself already in nineties [3], [4], being also independently driven by the contemporary research in robotics [5], an incessant progress in the integrated mechatronic design and novel actuator technologies set new challenges for motion control technologies. Likewise, the today's requirements on material-and energy-saving push the mechatronic systems towards sensor and actuator reduction, hence feedback degradation and underactuation, equally as towards more lightweight and therefore flexible (to say soft) structures. These trends burden a robust and efficient motion control with some ineluctable theoretical and practical issues of different nature. Among those are the plant, specifications, and disturbance modeling, variable structure systems, identification and state estimation, control robustness and adaptivity, and others.In this article, we partially review the state-of-the-art and discuss some recent and potential challenges of the motion control techniques and related developments. Our goal is to highlight and bring to attention of the interested auditorium of IEEE Industrial Electronics Society (IES) the principal features and associated issues of the controlled motion in advanced mechatronic systems and applications. By doing it, we are referring to the works published not only in IES journals and conferences but, rather, associated with a broadly spread research community around the motion control topics and affiliated technologies. Starting with basic principles of the motion stiffness and ideal versus disturbed motion under control, we clarify the vibrational perturbations owing to the structures, and damping perturbations owing to the friction on contact interfaces. The motion stiffness is introduced in Section I and that for an ideal position and force control, following by the mechanical impedance control as a more general case. In Section II we put an ideal versus disturbed motion under control, with associated canonical form of the state-space system modeling. Vibrational and frictional perturbations, as often most pronounced in the controlled m...

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