Experiments were carried out to investigate the positioning capability of a flexible arm. A shaft encoder was used as the sensor of the hub angle, while a laser beam was used to measure the slope of the deflection of the flexible robot arm. The control torque based on the output feedback control law was then applied to the motor through the driver circuits to control the arm. The experimental results show that the performance of the arm is satisfactory. Also, it is shown that the position controller is robust to parameter variations.>