In this paper, an acceleration sensor is utilized to calculate the absolute acceleration and velocity of the end-effector of a redundant 3-link planar manipulator. Generally speaking, the measurement of the acceleration sensor includes high-frequency noise and initial bias error, so a linear Kalman filter is applied to estimate exact acceleration information of the manipulator. In addition, joint-space disturbance observer (DOB) and work-space disturbance observer (WOB) are utilized to compensate the disturbance in joint-space and work-space respectively. The reliable estimated acceleration information from acceleration sensor is used in WOB under assumption that the absolute acceleration information makes WOB more effective to estimate disturbances in work-space in some cases. To evaluate the accuracy of the tip-position control using the estimated values of the acceleration information, some kinds of simulations and experiments are conducted in this research.