An　analytical　investigation　is　presented　into　active　residual　vibration　control　of　flexible　redundant　manipulators.　The　smart　links　are　fabricated　from　the　flexible　links　to　which　piezoelectric　actuators　and　strain　gage　sensors　are　attached.　The　state-space　expression　of　the　stochastic　dynamic　system　is　developed　firstly.　With　resort　to　the　minimum　principle,　a　LQG　state　feedback　controller　is　obtained.　In　addition,　a　continuous　Kalman　filter　is　designed　based　on　the　optimal　estimation　theory.　Finally,　a　planar　3R　flexible　redundant　manipulator　is　utilized　as　an　illustration　example.　Simulation　results　prove　the　validity　and　efficiency　of　this　active　vibration　control　strategy.