The study of NAO robot arm based on direct kinematics by using D-H method

Direct and inverse kinematics are commonly implemented to determine main parameters affecting humanoid robots behavior and specify the reliable method to control motion and preserve stability. This paper presents a direct kinematics method for humanoid NAO model. The approach is analytical based on classic methods like Denavit-Hartenberg convention which are employed to derive forward kinematics equations. Firstly, it analyses the upper limb topology of NAO model and establishes the kinematics models. Secondly, the homogeneous transformation matrix of upper limb joints of the robot is derived in this paper. Finally, the simulations are given by using the Robotic Toolbox from MATLAB software to test the derivation.