Aiming at the problem that the traditional biped robot model lacks the feet mass and the torso， a flexible biped robot model considering the influence of swing leg dynamics and torso was proposed， and its walking control and stability were studied. Firstly， the dynamics model of the system was established and the dynamics equation was deduced by the Euler-Lagrange method. At the same time， based on the Spring-Loaded Inverted Pendulum （SLIP） model， by adding rigid torso， foot mass， and adopting telescopic legs of variable length， the influence of the torso and the dynamics of swing legs on the gait of the robot was fully considered. Then， the feedback linearization controller based on variable length legs was designed to track the target trajectory and regulate the attitudes of the swing legs and the torso. Finally， the Newton-Raphson iteration method and Poincaré map were adopted to analyze the fixed point and orbital stability conditions of the robot. Simulation analysis was carried out based on theoretical analysis. Simulation results show that the proposed controller can realize the robot’s periodic walking and has good robustness to the external interference. And the moduli of all eigenvalues of the Jacobian matrix are less than 1， forming a stable limit cycle， which proves that the system has orbital stability.

Aiming at the problem of 3D trajectory estimation for mobile service robots in unknown environments, this thesis proposed a novel framework for using Kinect sensor to estimate the motion trajectory of mobile robots in real time. RGB-D information of successive frames in the environment was captured by a Kinect: firstly, the feature points of Speeded Up Robust Feature (SURF) of the target frame and reference frame were extracted and matched; secondly, initial 6 Degree Of Freedom (DOF) pose estimation was computed by a novel solution for the classical Perspective-3-Point (P3P) problem and an improved Random Sample Consensus (RANSAC) algorithm combining with depth information; lastly, the pose estimation was refined by minimizing the reprojection error of inliers of initial value via a nonlinear least-squares solver, and then the motion trajectory of the robot was gained. The experimental results show that the error of the odometry is reduced to 3.1% by the proposed approach in real time. It can provide important prior information for simultaneous localization and mapping of robots.

To solve the long handover latency of mobile network in NEtwork MObility (NEMO) Basic Support (NBS)，this paper proposed a scheme for NEMO within PMIPv6. Then an improved handover procedure for this scheme was suggested. The proposed scheme, which decreased the number of handover messages transmitted on wireless link and in advance set up the tunnel to forward packets, achieved fast handover of mobile network. Compared with NBS’s handover procedure, the analytical results show that the standard handover procedure and fast handover procedure of the proposed scheme decrease handover latency by 56.55% and 58.63% respectively.