Recent system developments for multi-actuator vibration control

This article discusses recent developments in multi-input multi-output (MIMO) vibration control systems and their applications to vibration testing. Highlights of some of the issues discussed are: 1) the proper control of singularities that exist in the system-under-test's frequency response matrix (FRM); 2) the benefits provided by a patented adaptive-control method; and 3) the advantages of characterizing the system-under-test with the simultaneous excitation from multiple actuators. These advanced methods provide the control-system user a better understanding of the system-under-test's dynamic characteristics and more realism during the test process. To illustrate this point, test results - those obtained during MIMO random, swept-sine and transient waveform control - will be presented. The test results will also be used to illustrate how the discussed advancements solve many of the MIMO-control problems associated with multi-actuator testing.