Positioning control of vibration systems such as flexible structures is one of the most fundamental technologies for mechanical structures. Different from feedforward control based methods, the use of LQ optimal regulator realizes the feedback control of vibrating parts of a controlled object. The author's previous paper proposed a control method switching from a simple feedforward access control technique to the LQ optimal regulator. That method does not require much computational load. However, its realization requires a Kalman filter based observer. This note investigates the use of the suboptimal control method such as the minimum norm method instead of the observer. The suboptimal controller based on a simple controlled object model generates responses similar to the LQ optimal regulator results. This improvement reduces the computational load further and realizes a very practical switching control method for many industrial applications. The effectiveness of this improvement is verified by numerical calculations and experiments.