The paper presents a simplified mathematical model of the two-legs walking robot with four degrees of freedom. It presents a novel sensing and balancing method for the bipedal robot with minimum possible for the walk degrees of freedom. The proposed method involves the design of semi-rigid ankle to facilitate fast and accurate measurements of the sideway (sagittal) instability of the walking robot. The use of new hip-mass carrying strategy in forward direction and system of two counter masses for the sideway body balancing allows to decouple the forward walking algorithms from the robot stability issues. The system of two different masses helps to improve response time and efficiency of the balancing system. The developed control algorithms provide continuous stability of the robot while it walks in forward direction by actuating its four DC motors. The smooth legs trajectory planning is implemented to minimize the foot-ground impact and jerky motions at the joints. The efficiency of the proposed control algorithms are tested and verified by using MATLAB Simulink computer tools.