An attempt has been made to develop a non-contact actuator consisting of a piezoelectric vibrator and a permanent magnet. In a simple control system the actuator dissipates energy and works as a damper. The actuator can also work as a negative damper, by supplying energy to the system and making it unstable. The demonstration of a negatively damped unstable system makes this experiment interesting for students.
DasA. S.NighilM. C.DuttJ. K.IrretierH., ‘Vibration control and stability analysis of rotor–shaft system with electromagnetic exciters’, Mechanism and Machine Theory, 43(10) (2008), 1295–1316.
