Positive position feedback (PPF) control is widely used in active vibration control of flexible structures. To ensure quick vibration suppression, a large PPF scalar gain is often applied. However, PPF control with a large scalar gain causes initial overshoot, which is undesirable in many situations. In this paper, a fuzzy gain tuner is proposed to tune the gain in the positive position feedback control to reduce the initial overshoot while still maintaining quick vibration suppression. The fuzzy system is trained by a batch least squares algorithm based on desired input–output data so that the trained fuzzy system can behave like the training data. A 3.35 m long composite I-beam with piezoceramic patch sensors and actuators is used to demonstrate the fuzzy PPF control. For comparison purposes, three types of control methods are used in the experiment: a standard PPF control, a standard PPF control with traditional fuzzy gain tuning, and a PPF control with batch least squares fuzzy gain tuning. Experimental results clearly demonstrate that PPF control with batch least squares fuzzy gain tuning behaves much better than the other two control methods in terms of successfully reducing the initial overshoot and quickly suppressing vibration.