An active control scheme is used for vibration suppression of a flexible multi-body dynamics model of a solar cell manipulator. The solar cell manipulator has large rotational or translational operation. The fork has a relatively small deformation on its tip. The floating frame of reference frame method (FFRF) is used to represent the flexible body. The result is compared to a commercial flexible multi-body dynamics analysis program to verify the developed program. While the manipulator is operating, the flexible fork shows vibration due to its high flexibility. The vibration influences the productivity, as it takes a few seconds for the tip to converge and a very small space is allowed for the fork to put the solar cell glass on a cassette. A state-space equation of the flexible fork model is derived and the control force equation is defined using gains. The control force is applied to the numerical model in order to suppress vibration of manipulator fork.