This work presents the kinematic modeling and motion planning algorithm for an omni-directional mobile robot with kinematic redundancy. This robot consists of three wheel mechanisms each of which has one redundant joint as compared to the operational degrees. Initially, the kinematic modeling of this robot is conducted. Next, using such a kinematic redundancy of each chain, several motion planning algorithms are suggested. A localization algorithm of the mobile robot based on odometry is presented and specifically, two-leveled obstacle avoidance scheme, which simultaneously considers both large and small obstacles, is presented. The usefulness of the proposed algorithms is verified through simulation.

In previous studies on 4-DOF parallel mechanisms with four sub-chains, only symmetric arrangement of those four chains connected to the top plate was considered. Such symmetric shape sometimes falls into a sort of architetural singularity. This work demonstrates that an asymmetric placement of the four chains on the top platform is desired to minimize the effect of such architectural singularity. A new 4-DOF parallel mechanism exhibiting 4-DOF motion (3-DOF translational motion and one rotational motion) is examined as an exemplary device. This device consists of a base plate, an upper plate, and four hybrid subchains connecting those two plates together. The position analysis and kinematic modeling for this mechanism are performed, and an optimal design with respect to the workspace size and the kinematic isotropic characteristic is conducted. A set of offset angles on the top platform is found, which significantly minimizes the architectural singularity problem within the valid workspace of the mechanism. Then, through the analysis of the workspace and kinematic isotropic property for the optimized mechanism, its high potential for real applications is confirmed. Finally, the mechanism was developed to verify the motion capability.

Less degree-of-freedom robots are useful for special applications. Specifically, practical application of 4-DOF parallel mechanism has been rare, though synthesis on this type has been conducted quite a few. Recently, we proposed a revolute joint-based 3T1R 4-DOF parallel mechanism having Schonflies motions whose output rotational motion is a roll motion. This work proposes another type of a new 3T1R 4-DOF parallel mechanism having Schonflies motions whose rotational motion is a pitch motion. The position analysis and kinematic modeling for the mechanism are performed, and its workspace size and kinematic characteristic with respect to the kinematic isotropic characteristic are examined. To support high potential of the mechanism for real applications, three different versions are suggested and each motion capability is verified through its simulator. Finally, a prototype is developed to verity its actual motion capability.