Ki Cheol Park

Analysis and control of redundant manipulator dynamics based on an extended operational space

In this paper a new concept, named the Extended Operational Space (EXOS), has been proposed for the effective analysis and the real-time control of the robot manipulators with kinematic redundancy. The EXOS consists of the operational space (OS) and the optimal null space (NS): the operational space is used to describe manipulator end-effector motion; whereas the optimal null space, described by the minimum number of NS vectors, is used to express the self motion.Based upon the EXOS formulation, the kinematics, statics, and dynamics of redundant manipulators have been analyzed, and control laws based on the dynamics have been proposed. The inclusion of only the minimum number of NS vectors has changed the resulting dynamic equations into a very compact form, yet comprehensive enough to describe: not only the dynamic behavior or the end effector, but also that of the self motion; and at the same time the interaction of these two motions. The comprehensiveness is highlighted by the demonstration of the dynamic couplings between OS dynamics and NS dynamics, which are quite elusive in other approaches.Using the proposed dynamic controls, one can optimize a performance measure while tracking a desired end-effector trajectory with a better computational efficiency than the conventional methods. The effectiveness of the proposed method has been demonstrated by simulations and experiments.

A new kind of singularity in redundant manipulation: semi algorithmic singularity

Reports the discovery of a new type of singularity that is as significant as other singularities like kinematic singularity, algorithmic singularity, and semi-singularity. This singularity, named semi algorithmic singularity (SAS), occurs when a redundant manipulator, faced with inequality constraints arising from kinematic limits such as joint angle limits and obstacles, proceeds to conduct optimization of a performance measure. Through mathematical analysis, we have proved its existence and proposed an analytic matrix function to identify its presence. In conjunction, we have exposed its relationship with the other singularities above. More specifically, SAS is similar to the algorithmic singularity in that it is an artificial singularity coming from an endeavor for performance optimization. They are different in that the former occurs in one direction in the C-space, whereas the latter occurs bidirectionally. Besides, we have also found an analogy in the real singularities that while the semi-singularity is unidirectional in the workspace, the kinematic singularity is bi-directional. Through a simulation for a three DOF planar manipulator we have visualized the existence of SAS and its relationship with the other singularities.

Ubiquitous robot S/W platform and its application: AnyRobot Studio and AnyKids Service

The standardized data may easily move within a network and connect to other systems without any time or geographical limitations. This concept is fundamental to the idea of the ubiquitous robot. But the definitions of the ubiquitous robot or networked robot appear in different forms all over the world. This paper discusses those definitions briefly including the approach of Samsung Electronics Co., Ltd (SEC). Here we present a ubiquitous robotic S/W platform, AnyRobot Studio which covers all the aspects of this ubiquitous robot system. Based on the concepts of RUPI, URC, and Web 2.0, AnyRobot Studio aims to standardize the platforms and protocols, and to strongly encourage the participation of users and contents providers (CPs). AnyKids Service is made to test the feasibility of the AnyRobot based on the AnyRobot Studio platform.

Ubiquitous robot S/W platform, AnyRobot Studio and its demonstration, AnyKids Service

The standardized data may easily move within a network and connect to other systems without any time or geographical limitations. This concept is fundamental to the idea of the ubiquitous robot. Here we present a ubiquitous robot S/W platform, AnyRobot Studio which covers all the aspects of this ubiquitous robot system. Based on the concepts of RUPI, URC, and Web 2.0, AnyRobot Studio aims to standardize the platforms and protocols, and to strongly encourage the participation of users and contents providers (CPs). AnyKids Service is made to test the feasibility of the AnyRobot based on the AnyRobot Studio platform.