Investigation of Local and Modal Based Active Vibration Control Strategies on the Example of an Elastic System

Abstract

Nowadays, feed axes are often equipped with multiple parallel-acting actuators in order to increase the dynamics of the machine tool. Also, additional actuators for active damping are widely used. Normally, the drives or actuators are controlled independently without consideration for the impact on each other. In contrast, by using the modal space control, the system can be decoupled and the modal control loops can be adjusted independently. This control approach is particularly suitable for motion systems, such as machine tools, which have more drives or actuators than degrees of freedom of movement. This paper deals with the pre-investigation of the modal-based vibration control for machine tools with additional actuators. The object of investigation is an elastic system with a movable saddle. The modal-based control is compared with a local control approach. The results obtained experimentally on the test rig are presented. The modal control is superior since, with the modal approach, each control loop corresponds to a specific vibration mode, and the control law for this loop is designed to provide the desired performance of the control system at the corresponding resonance frequency. The parameterisation of the control loops is simplified by modal control, since the modes can be controlled independently.

Generalized mathematical formulation for active vibration control of rotating machines with voltage‐driven electrodynamic actuators between machine feet and steel frame foundation

“…A typical excitation frequency of rotating machines is the rotor frequency (e.g., excitation by mechanical unbalance). In this case the excitation angular frequency 𝜔 e has to be replaced by the rotor angular frequency Ω in Equations (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37).…”

“…Sato et al analyzed in [23] the robustness of a model-free controller based on a virtual structure, where this virtual structure was positioned between a proof mass electrodynamic actuator and a controlled object. Peukert et al investigated in [24] local and modal-based active vibration control strategies in the example of an elastic system, using proof mass electrodynamic actuators for an elastic system with a movable saddle. Pérez-Aracil et al investigated in [25] passive and active vibration isolation under isolator-structure interaction for vertical excitations.…”

“…In many cases, critical speeds, occurring in the operation speed range and leading to resonance problems [2–6], are the cause, induced by a large operating speed range in conjunction with an elastic steel frame foundation. A solution could be, to implement active vibration control, which is used in many different applications [7–29]. To use active vibration control for rotating machines is not new.…”

“…Peukert et al. investigated in [24] local and modal‐based active vibration control strategies in the example of an elastic system, using proof mass electrodynamic actuators for an elastic system with a movable saddle. Pérez‐Aracil et al.…”

Modal synthesis of precision control systems

“…The principle of modal control, due to the most complete reflection of the cybernetic essence of state feedback, is widely used to control lightly damped, structurally unstable and nonstationary objects [1][2][3][4][5][6][7][8][9][10].…”