Design, Mobility and Kinematic Analysis of a 4R1H Mechanism

The article presents design, mobility and kinematic analysis of a 1-DOF 4R1H mechanism. Here, R designates a revolute joint and H designates a helical joint. The considered mechanism is designed using two kinematic chains that correspond to planar and screw motions. As a result, all the links of the mechanism form a planar structure, while its output link moves along a spatial closed-loop helical-like trajectory with a curvilinear axis. Such a movement can be suitable for mixing operations. The paper applies screw theory to analyze mechanism mobility and prove that it has one degree-of-freedom. Kinematic analysis follows next and provides analytical relationships between the input coordinates and coordinates of the output link. Based on theoretical algorithms, the paper considers a numerical example for specific parameters of the mechanism. A computer-aided design simulation verifies the analytical results.