The human arm manipulator, mechanism, kinematics, and dynamics
Mechanical robot manipulators so far developed are mainly single-arm systems. When applications of robot manipulators to the human arms for handicapped people or a human-resembled-double-arm robot is considered, there is no proper type of manipulator developed yet. Moreover, when tasks assigned to robot manipulators are in a critical working condition or the nature of tasks is not known, a multi-arm system is considered to be better in mechanical structure. Thus, a new mechanical manipulator system, that resembles human arms, was proposed and named the Human Arm Manipulator. The basic mechanism of robot manipulators was studied, and the Stanford Manipulator and the Elbo Manipulator were introduced to compare with the Human Arm Manipulator. To drive kinematics and the solutions of variables for HAM, 4 x 4 homogeneous transformation matrices were used. And during the procedure of driving kinematics, conventional spatial description using Denavit-Hartenberg presentation was modified, and definitions of parameters were changed to make them consistent. By doing this, the modified Denavit-Hartenberg presentation becomes more systematic and expanded, but does not conflict with the original one. For the manipulator dynamics, various research papers were studied, and basic approaches, that is, the Lagrange-Euler approach and the Newton-Euler approach, were introduced. For dynamics of the Human Arm Manipulator, Newton-Euler formulation was applied. To reduce computing time for dynamic equations, 3 x 3 rotation transformation matrices and position vectors were used. The relations between 4 x 4 homogeneous matrices and 3 x 3 rotation and column position matrices were studied, and 3 x 3 rotation and column position matrices were driven from a general 4 x 4 homogeneous matrix. The differences of results between the Denavit-Hartenberg spatial description and a modified one were shown, but the results of modified presentation contain those of Denavit-Hartenberg without conflict. The rotation and position matrices, constants, and parameters that were required for the computation of Newton-Euler formulation for the Human Arm Manipulator were introduced.