Dual Arm Robot(II)

Analytical Inverse Kinematics Solution for Modularized Dual-Arm Robot With offset at shoulder and wrist

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Generally, an industrial manipulator such as PUMA560 is equipped with 6 degrees of freedom(DoF), it is just enough to reach a position and orientation in 3-D space. However, to achieve dexterous movement like the upper limb of human, different with normal industrial manipulators, such manipulators equipped with 7-DoF kinematic structure is desirable. With the redundant joint, such manipulators may accomplish tasks such as obstacle-avoidance and singularity avoidance while reaching target position at the same time. These tasks are all about manipulator kinematics. However, when one wants to utilize advantages of redundant manipulators, one encounters problem of solving inverse kinematic problem of such manipulators. There is two ways to solve manipulator kinematic problem, one is numerical method and the other is analytical method. Traditionally, it used numerical method to deal with kinematics problem is a traditional way. However, solving Jacobian matrix is rather tedious, not to mention solving its inverse. Also, the relation between joint space and Cartesian space of an arm is not linear, obtaining joint values by numerical method is not satisfactory.

Since that, we develop an analytical inverse kinematic solution for modularized 7-DoF redundant manipulators with offsets at shoulder and wrist and derive analytical inverse kinematic solutions based on different joints as redundnt for it. The manipulator shown in Figure 1 is one of the dual arm robot developed by our laboratory, which is a modularized 7-DoF manipulator with offsets at shoulder and wrist.