This paper works on improving stability and balance with three degrees of freedom dynamic balancing waist on the adult-sized humanoid robot, David II. In order to make this adult-sized humanoid robot better than its previous version, the waist joint is assigned 3-DOF which is used to adjust the trunk. In addition, this paper also presents how the sensors work with double-stage sensor fusion filter in embedded system as well. The feedback control system continuously renews the angular position of servo motors to promote and improve the walking ability to adapt environmental change and various terrains. The results are demonstrated in the humanoid league of RoboCup Japan Open 2013 and the HuroCup of FIRA.