Machine tools’ feed dynamics are usually limited in order to reduce excitation of machine structure oscillations. Consequently, the potential increase in productivity provided by direct drives, e.g. linear motors, cannot be exploited. The novel approach of the Kinematically Coupled Force Compensation (KCFC) applies a redundant axis configuration combined with the principle of force compensation and thus achieves an increase in feed dynamics while drive reaction forces cancel out each other in the machine base. In this paper, the principle of KCFC is introduced briefly. Subsequently, the basics for the realisation of a highly dynamic KCFC motion system with planar motion are derived and discussed. In order to achieve highest acceleration (> 100 m/s2) and jerk (> 100000 m/s3), a mechatronic system with specially designed components for the mechanical, electrical and control system is required. Thus, the design approach presented in this paper applies lightweight slides, a decoupled guide frame and voice coil motors operated at high frequencies for the pulse width modulation and control loops.
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.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.