• International conference on construction engineering and project management
• /
• 2013.01a
• /
• pp.163-168
• /
• 2013

A construction workspace is considered as a critical factor to secure constructability and safety of a project. Specially, optimized size of each workspace helps to minimize any conflicts between workspaces, works and resources within a workspace in the construction site. However, since an existing method for making a decision workspace's size depends on generally experiences of managers and work conditions of activity, it is difficult to perform safe works considering feasible workspace size. The workspace size is changed according to the quantity of resources allocated into each activity as time progresses. Accordingly, it is desirable that optimized workspace size considering input size of resources is determined. To solve these issues, this study configures an optimized model for deciding standard size of workspaces by simple regression analysis and develops a visualized scenario model for simulating the optimized workspace shape in order to support BIM (Building Information Modeling) environment. For this, this study determines an optimized resource shape size considering maximum working radius of each resource and constructs its visual model. Subsequently, input size of resources for each activity is estimated considering safety execution area of resources and workspaces. Based on this, an optimized 3D workspace shape is generated as a VR simulation model of a BIM system based on the suggested methodologies. Moreover, operational feasibility of the developed system is evaluated through a case study for a bride project. Therefore, this study provides a visualized framework so that project managers can establish an efficient workspace planning in BIM environment. Besides, it is expected that constructability, productivity and safety of the project will be improved by minimizing conflicts between workspace and congestions between resources within a workspace in the construction phase.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.3
• /
• pp.322-328
• /
• 2011

This paper presents inverse kinematics and workspace analysis of a planar three degree-of-freedom (DOF) parallel manipulator. Furthermore, optimization problem of the manipulator is presented. The manipulator adopts PRR (Prismatic-Revolute-Revolute) mechanism and the prismatic actuators are fixed to the base. This leads to a reduction of the inertia of the moving links and hence enables it to move with high speed. The actuators are linear electric motors. First, the mechanism based on the geometry of the manipulator is introduced. Second, a workspace analysis is performed. Finally, design optimization is carried out to have large workspace. The proposed approach can be applied to the design optimization of various three DOF parallel manipulators in order to maximize their workspace. The performance of mechanism is improved and satisfies the requirements of workspace to align micro-components.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.6
• /
• pp.477-483
• /
• 2002

This paper deals with a workspace analysis of multi-legged walking robots in velocity domain(velocity workspace analysis). Noting that when robots are holding the same object in multiple cooperating robotic arm system the kinematic structure of the system is basically the same with that of a multi-legged walking robot standing on the ground, we invented a way ot applying the technique for multiple arm system to multi-legged walking robot. An important definition of reaction velocity is made and the bounds of velocities achievable by the moving body with multi-legs is derived from the given bounds on the capabilities of actuators of each legs through Jacobian matrix for given robot configuration. After some assumption of hard-foot-condition is adopted as a contact model between feet of robot and the ground, visualization process for the velocity workspace is proposed. Also, a series of application examples will be presented including continuous walking gaits as well as several different stationary posture of legged walking robots, which validate the usefulness of the proposed technique.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.1
• /
• pp.60-68
• /
• 1998

Parallel link manipulators have an ability of more precise positioning than serial open-loop manipulators. However. general parallel link manipulators have been restricted to the real applications since they have limited workspace due to interference among actuators. In this study, we suggest a closed-loop manipulator with 6 degrees-of-freedom and with enlarged workspace. It consists of two parts for minimizing the interference among actuators. One part is lower structure with planar 3 degrees-of-freedom and the other is upper one with spatial 3 degrees-of-freedom. Forward kinematics and inverse kinematics are solved, research about singularity points are carried out and workspace is evaluated. The comparison of workspace between Stewart platform, which is the typical parallel link manipulator, and the suggested manipulator shows that the workspace of the latter is wider than that of the former. Especially, simulation results also show that the suggested manipulator is more suitable when there needs rotation in the end-effector.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1655-1658
• /
• 2003

The application area of parallel mechanism is limited in spite of many advantages of that because the workspace of platform is a very small. Thus enlargement of workspace is important issue in design of parallel mechanism. In this paper a parallel mechanism design method is described using commercial simulation program. Firstly strokes of the assembled parallel mechanism's active joints are simulated from kinetic simulation mode to get required workspace, Secondly, dynamic parameters(velocity, acceleration, force, moment) are simulated for the gravity, friction and exit load. Finally, workspace of moving platform is displayed and workspace of area is simulated by motion analysis. The results of this paper will help engineer to design parallel mechanism with optimize workspace.

• The Journal of Korea Robotics Society
• /
• v.7 no.2
• /
• pp.101-112
• /
• 2012

It is well-known that when singularities are located within the workspace of the parallel mechanism (PM), the usefulness of its workspace is significantly deteriorated. To handle this problem, we suggest an optimal design method which leads to more useful and larger workspace of the PM by taking its singularity locations into consideration in design process. Kinematic models of three selected planar PMs, a 5R type PM, a 3-RPR type planar PM, and a 3-RRR type planar PM, are derived via screw theory and their singularity analyses are conducted. Then workspace optimal designs for those three PMs are conducted to verify that the suggested design method leads more useful and larger workspace in which deterioration by singularity is minimal.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.05a
• /
• pp.973-974
• /
• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.765-768
• /
• 1995

A double parallel manipulator has only two or three links in each parallel mechanism. this reduces link interferences so that we expect a large workspace. To prove this property, this paper analyzes the workspace of a double parallel manipulator and compare it with that of a Stewart Platform. the analysis is separately conducted in a positional and an orientational division. For each, we obtain the workspace accrding to the ranges of lengths of links and show the volume in a cartesian coordinate or the angular ranges in yaw and pitch motions.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.23 no.2
• /
• pp.158-165
• /
• 2013

This paper presents design and workspace analysis of a Korean home service robot. The robot is designed with specific needs of floor-task applications suitable for Korean life style. Shoulder and waist of the robot are adjusted by sliding mechanism to increase the workspace of the robot arms. Manipulators are designed and built and their workspaces are analyzed. Experimental studies of the robot for cleaning the floor are conducted.

• Journal of Mechanical Science and Technology
• /
• v.17 no.4
• /
• pp.528-537
• /
• 2003

This paper proposes a 3-PPR planar parallel manipulator, which consists of three active prismatic Joints, three passive prismatic joints, and three passive rotational joints. The analysis of the kinematics and the optimal design of the manipulator are also discussed. The proposed manipulator has the advantages of the closed type of direct kinematics and a void-free workspace with a convex type of borderline. For the kinematic analysis of the proposed manipulator, the direct kinematics, the inverse kinematics, and the inverse Jacobian of the manipulator are derived. After the rotational limits and the workspaces of the manipulator are investigated, the workspace of the manipulator is simulated. In addition, for the optimal design of the manipulator, the performance indices of the manipulator are investigated, and then an optimal design procedure Is carried out using Min-Max theory. Finally. one example using the optimal design is presented.