• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.9
• /
• pp.971-977
• /
• 2012

Redundant actuated parallel kinematic machines (PKMs) have been widely researched to increase stiffness of PKMs. This paper presents theoretical analyses on the stiffness of non-redundant and redundant actuated PKM. Stiffness of each mechanism is defined by summation of actuator and structural stiffness; the actuator stiffness is determined from displacements of actuators, and the structural stiffness is determined from deformations of links by external forces. Calculated actuator and structural stiffness of non-redundant PKM show same distribution in entire workspace. On the contrary, the actuator and the structural stiffness of a redundant PKM has very different distribution in the workspace; so, we conclude the structural stiffness of redundant PKM should be considered to design the redundant PKM. The results can be used to design and analyze non-redundant and redundant PKMs.

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.26-30
• /
• 1986

This survey paper presents a review of control methods for redundant robot manipulators. Use of redundant degree of freedoms by local and global optimization techniques are described in terms of the Jacobian matrix equation for the redundant robot manipulators. Relevant problems for further use of redundant robot manipulators are then discussed.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.730-733
• /
• 1996

This paper presents the kinematic and dynamic analysis of parallel manipulators with redundant limbs, obtained by putting additional limbs to an existing parallel manipulator. We develop the kinematic and dynamic models of a parallel, manipulator with redundant limbs. The redundancy in parallelism due to the increased number of limbs and the redundancy in actuation due to the increased number of active joints are considered in the modeling. Based on the derived models, we define the kinematic and dynamic manipulabilities of a parallel manipulator with redundant limbs. The effect of the redundant limbs on the performance of parallel manipulators is analyzed in terms of kinematic and dynamic manipulabilities.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.371-374
• /
• 1996

This paper presents the kinematic and dynamic analysis of parallel manipulators with redundant joints, obtained by putting additional active joints to an existing parallel manipulator. We develop the kinematic and dynamic models of a parallel manipulator with redundant joints. The redundancy in serial chain, due to the increased number of joints per limb, is considered in the modeling. Based oh the derived models, we define the kinematic and dynamic manipulabilities of a parallel manipulator with redundant joints. The effect of the redundant joints on the performance of parallel manipulators is analyzed in terms of kinematic and dynamic manipulabilities.

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.2
• /
• pp.181-189
• /
• 2000

This paper presents the optimal redundant actuation of parallel manipulators for complicated robotic applications such as cutting grinding drilling and digging that require a high degree of operational stiffness as well as the balance between force applicability and dexterity. First by taking into account the distribution(number and location) of active joints the statics and the operational stiffness of a redundant parallel manipulator are formulated and the effects of actuation redundancy are analyzed, Second for given task requirements including joint torque limit task force maximum allowable disturbance and maximum allowable deflection the task execution conditions of a redundant parallel manipulator are derived and the efficient testing formulas are provided. Third to achieve high operational stiffness while maintaining moderate dexterity the redundant actuation of a parallel manipulator is optimized which determines the optimal distribution of active joints and the optimal internal joint torque, Finally the simulation results for the optimal redundant actuation of a planar parallel manipulator are given.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.127-130
• /
• 1989

The redundant manipulator extends the application fields of classical nonredundant manipulators. In this paper, we propose Premultiplier Model that describes the static behavior of redundant manipulator. This model provides insight and intuition about algebra and physics related to redundant manipulators. Active operational space stiffness control of redundant manipulators is proved to be always unstable and we propose a technique, based on our methodology, to make stiffness control stable.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10c
• /
• pp.496-498
• /
• 2000

현재 이동 컴퓨팅 연구 중에서 이동 호스트의 결함을 효율적으로 대처하는 결함 허용 기법에 관한 연구가 미미한 실정이다. 이동 호스트의 결함 복구 기법인 Lazy 기법은 비용 면에서는 효율적이지만 이동 호스트의 체크포인트를 소유하고 있는 기지국의 결함 발생시 이동 호스트가 결함으로부터 복구될 수 없다는 단점을 가지고 있다. Redundant Lazy 기법은 연결 리스트를 중복화 함으로서 Lazy 기법의 문제점을 해결한 기법이다. 그러나 Redundant Lazy 기법도 체크포인트를 가지고 있는 기지국의 결함이 발생하면 이동 호스트가 복구될 수 없는 경우가 발생한다. 본 논문에서는 이중 셀룰라 네트워크에 Redundant Lazy 기법을 적용하여 이러한 문제를 해결할 수 있는 성능 개선 방안을 논의한다.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.52 no.5
• /
• pp.97-108
• /
• 2010

The objective of this study is to develop evaluation indices which can be applied to analyze rational rehabilitation-policy directions of redundant farmlands. To achieve this objective, the main tasks of this research are 1) categorizing the redundant farmlands rehabilitation types 2) developing the evaluation indices of redundant farmlands rehabilitation 3) determining the weights of each index. The redundant farmlands rehabilitation types were classified into agricultural rehabilitation type, non-agricultural rehabilitation type and hybrid type which are called by agricultural income model, rural environment improvement model and hybrid model as development project name, respectively. The 5 parts and 21 indices for evaluation of redundant farmlands rehabilitation directions were extracted by case studies and experts brainstorming. The weights of each index were determined by Analytic Hierarchy Process (AHP). The developed evaluation indices were applied to study areas located on Yanghwa district of Gongju-city and Aewol district of Jeju-city. From the results of this study, it was ascertained that the evaluation indices developed in this study would help the decision-makers in the planning process of redundant farmlands rehabilitation directions.

• International Journal of Reliability and Applications
• /
• v.9 no.2
• /
• pp.141-152
• /
• 2008

This paper presents equations, which can be used to evaluate the failure frequency and the failure rate of a two identical component parallel redundant system in which each component can operate in its wear out period, and the failure rate of each component is exponential power distribution. The optimum maintenance interval for a two identical component parallel redundant system can be obtained using these equations. The proposed approach is presented and illustrated using several numerical examples. The optimum maintenance interval for each component in a two identical parallel redundant system will depend on factors such as: failure rate, repair and maintenance times of each component in the parallel redundant systems.

• Proceedings of the KIEE Conference
• /
• 2005.05a
• /
• pp.148-151
• /
• 2005

This paper proposes a high speed interface using redundant multi-valued logic for high speed communication ICs. This circuit is composed of encoding circuit that serial binary data are received and converted into parallel redundant multi-valued data, and decoding circuit that convert redundant multi-valued data to parallel binary data. Because of the multi-valued data conversion, this circuit makes it possible to achieve higher operating speeds than that of a conventional binary logic. Using this logic, a 1:4 demultiplexer (DEMUX, serial-parallel converter) IC was designed using a 0.35${\mu}m$ standard CMOS Process. Proposed demultiplexer is achieved an operating speed of 3Gb/s with a supply voltage of 3.3V and with power consumption of 48mW. Designed circuit is limited by maximum operating frequency of process. Therefore, this circuit is to achieve CMOS communication ICs with an operating speed greater than 3Gb/s in submicron process of high of operating frequency.