Minimum Torque Placement of a Kinematic Structure

2001 ◽  
Author(s):  
Wei Yu ◽  
Jingzhou Yang ◽  
Karim Abdel-Malek
Keyword(s):  
Design Process ◽  
Infinite Number ◽  
Significant Contribution ◽  
Optimization Methods ◽  
Working Environment ◽  
Kinematic Structure ◽  
Ergonomic Design ◽  
Number Of Solutions ◽  
The Given ◽  
Minimum Torque

Abstract A general formulation for calculating where a kinematic structure must be positioned (and oriented) is presented. This study is applicable to both humans; to place a human in a working environment while minimizing stress on extremity joints, or for robot manipulators. In recent years, there has been focused interest on ergonomics and ergonomic design with emphasis on the disposition of a worker while performing tasks at prolonged periods of time and where repetitive motions are exerted. To a great extent, the effect of stress on a joint is major factor leading to potential injuries. We believe there is a unique opportunity for the mechanical engineering community to make a significant contribution to this field. Furthermore, because the ergonomic design process encompasses many parameters, it is evident that it must be formulated using optimization methods where the best possible solution is calculated from an infinite number of solutions. This study presents a rigorous formulation for placement of a worker based on minimizing the torque (as a cost function) induced at a joint, whereby satisfying constraints imposed by the given task. The reverse of this problem is the calculation of the coordinates of a number of target points in the reachable space of a fixed kinematic structure, which is also addressed. Both problems are mathematically formulated and numerically solved. Examples are illustrated.

Optimization Methods for Calculating Design Imprecision

1995 ◽  
Author(s):  
William S. Law ◽  
Erik K. Antonsson
Keyword(s):  
Fuzzy Sets ◽  
Design Process ◽  
Optimization Methods ◽  
Experiment Design ◽  
Design Evaluation ◽  
Preliminary Design ◽  
New Methods ◽  
Evaluation Functions ◽  
Incomplete Design ◽  
Alternative Designs

Abstract The preliminary design process is characterized by imprecision: the vagueness of an incomplete design description. The Method of Imprecision uses the mathematics of fuzzy sets to explicitly represent and manipulate imprecise preliminary design information, enabling the designer to explore the space of alternative designs in the context of the designer and customer’s preferences among alternatives. This paper introduces new methods to perform Method of Imprecision calculations for general non-monotonic design evaluation functions that address the practical necessity to minimize the number of function evaluations. These methods utilize optimization and experiment design.

Free-surface flows with two stagnation points

1996 ◽  
Vol 324 ◽  
pp. 393-406 ◽  
Author(s):  
J.-M. Vanden-Broeck ◽  
F. Dias
Keyword(s):  
Free Surface ◽  
Infinite Number ◽  
Wave Breaking ◽  
Free Surface Flows ◽  
Number Of Solutions ◽  
Surface Flows ◽  
Stagnation Points ◽  
Surface Profiles ◽  
Countably Infinite

Symmetric suction flows are computed. The flows are free-surface flows with two stagnation points. The configuration is related to the modelling of wave breaking at the bow of a ship. It is shown that there is a countably infinite number of solutions and that the free-surface profiles are characterized by waves.

SUSTAINABILITY ASSESSMENT METHODOLOGY IN PRODUCT DESIGN: A REVIEW AND DIRECTIONS FOR FUTURE RESEARCH

2016 ◽  
Vol 79 (1) ◽  
Author(s):  
Mohd Fahrul Hassan ◽  
Muhamad Zameri Mat Saman ◽  
Salwa Mahmood ◽  
Nik Hisyamudin Muhd Nor ◽  
Mohd Nasrull Abdol Rahman
Keyword(s):  
Product Design ◽  
Design Process ◽  
Sustainability Assessment ◽  
Integrated Design ◽  
Working Environment ◽  
Future Research ◽  
Sustainable Product Design ◽  
Great Opportunity ◽  
Product Design Process ◽  
Sustainable Product

To achieve sustainable product design, it is crucial to use sustainability assessment during the product design process. In this paper, numerous sustainability assessment methodologies in product design are reviewed. A comprehensive assessment of sustainability has been reported to present better performance for improving product sustainability. This review focused on the consideration of sustainability elements by previous researchers that have proposed integrated design tools, commercial software tools and combination both methods in supporting the methodologies. Based on this review, it can be concluded that the inclusion of sustainability performance among the assessment criteria in the design process activities is suggested as a critical point of concern which presents a challenge and is a great opportunity to develop useful guidelines or directions for industries or any product-based project so that the proposed approach will be accepted for implementation in the working environment.

scholarly journals Ergonomic design with the use of augmented reality techniques

Mechanik ◽  
2018 ◽  
Vol 91 (1) ◽  
pp. 82-84
Author(s):  
Marcin Januszka ◽  
Wojciech Krysta
Keyword(s):  
Augmented Reality ◽  
Design Process ◽  
Flat Surface ◽  
Real Space ◽  
Ergonomic Design ◽  
Work Spaces ◽  
Innovative System

The paper presents an innovative system for aiding ergonomic design of work spaces. Aiding is realised with the use of augmented reality techniques which allow to move the design process from a flat surface of a computer’s monitor to a real space around the designer.

A Proposed Method to Group the Solutions From Dimensional Synthesis: Planar Triads for Six Precision Position

1992 ◽  
Author(s):  
Xiancheng Lu ◽  
Chuen-Sen Lin
Keyword(s):  
Infinite Number ◽  
Numerical Solutions ◽  
Angular Displacement ◽  
Dimensional Synthesis ◽  
Number Of Solutions ◽  
Jacobian Matrices ◽  
Design Task ◽  
Numerical Examples ◽  
Computer Automation ◽  
Constraint Sets

Abstract In this paper, a method has been proposed to group into six sets the infinite number of solutions from dimensional synthesis of planar triads for six precision positions. The proposed method reveals the relationships between the different configurations of the compatibility linkage and the sets of numerical solutions from dimensional synthesis. By checking the determinant signs and the contunities of values of the sub-Jacobian matrices and their derivatives with respect to the independent angular displacement for all constraint sets in the compatibility linkage, it enables the computer to identify and group the synthesized solutions. Numerical examples have been given to verify the applicability of this method. Six sets of the partial triad Burmester curves have been plotted based on grouped solutions. Suitable solutions can be easily found from the partial triad Burmester curves and utilized for the prescribed design task. This method provides a useful tool to group the dimensional synthesis solutions and enhances the computer automation in the design of linkage mechanisms.

A Decomposition Method for Concurrent Design of Mixed Discrete/Continuous Systems

1993 ◽  
Author(s):  
Jeffrey M. Ford ◽  
Christina L. Bloebaum
Keyword(s):  
Design Process ◽  
Decomposition Method ◽  
Organizational Design ◽  
Method Development ◽  
Minimum Weight ◽  
Optimization Methods ◽  
Continuous Systems ◽  
Computationally Efficient ◽  
Subspace Optimization ◽  
Design Variables

Abstract Interest in Concurrent Engineering (CE) has increased as industry looks for more efficient means of product design. Design optimization methods that facilitate the CE approach are an important aspect of current research. Among the methods that have been proposed is the Concurrent Subspace Optimization (CSSO) method, which allows the optimization problem to be decomposed into coupled subproblems. These subproblems may correspond to the different disciplines involved in the design process or to participating organizational design or manufacturing groups. The decomposition allows each discipline to apply their own optimization criteria to the problem. While this method may not be as computationally efficient as other methods, it allows the design process to conform to the departmental divisions that already exist in industry. The method development to date has focused on continuous systems only. However, problems that can not be modeled as continuous systems, such as those involving the placement of active controllers in CSI applications, would benefit from a method that allows the use of discrete parameters. The paper presents a decomposition method (based on CSSO) for the optimal design of mixed discrete/continuous systems. The method is applied to the design of a composite plate for minimum weight, with design variables contributed from sizing variables (continuous) and material combinations (discrete).

Direct Optimization of Multi-Degree-of-Freedom Mechanisms for Near Time Optimal Motions Along Specified Paths

1991 ◽  
Author(s):  
Satish Sundar ◽  
Zvi Shiller
Keyword(s):  
Design Method ◽  
Close Correlation ◽  
Optimization Methods ◽  
Degree Of Freedom ◽  
Design Parameters ◽  
Direct Optimization ◽  
Fitting Procedure ◽  
Time Optimal ◽  
Approximate Cost ◽  
The Given

Abstract A design method for selecting system parameters of multi-degree-of-freedom mechanisms for near minimum time motions along specified paths is presented. The time optimization problem is approximated by a simple curve fitting procedure that fits, what we call, the acceleration lines to the given path. The approximate cost function is explicit in the design parameters, facilitating the formulation of the design problem as a constrained optimization. Examples for optimizing the dimensions of a five-bar planar mechanism demonstrate close correlation between the approximate and the exact solutions and better computational efficiency than the previous unconstrained optimization methods.

scholarly journals Spectrum of a Differential Operator with Periodic Generalized Potential

2007 ◽  
Vol 2007 ◽  
pp. 1-8
Author(s):  
Mehmet Sahin ◽  
Manaf Dzh. Manafov
Keyword(s):  
Differential Operator ◽  
Infinite Number ◽  
Periodic Potential ◽  
Generalized Functions ◽  
Order Differential Operator ◽  
Nonzero Constant ◽  
Classic Case ◽  
First Order ◽  
Generalized Potential ◽  
The Given

We study some spectral problems for a second-order differential operator with periodic potential. Notice that the given potential is a sum of zero- and first-order generalized functions. It is shown that the spectrum of the investigated operator consists of infinite number of gaps whose length limit unlike the classic case tends to nonzero constant in some place and to infinity in other place.

scholarly journals Solar.q_1: A new solar-tracking mechanism based on four-bar linkages

2016 ◽  
Vol 231 (15) ◽  
pp. 2855-2867 ◽  
Author(s):  
Giuseppe Quaglia ◽  
Simone Luca Maurino
Keyword(s):  
Energy Consumption ◽  
Design Process ◽  
Control Strategy ◽  
Parallel Mechanism ◽  
Polar Axis ◽  
The Sun ◽  
Kinematic Structure ◽  
Photovoltaic Panels ◽  
Early Stages ◽  
Solar Tracking

This paper describes the early stages of the design process of a 2-DOF parallel mechanism, based on the use of four-bar linkages and intended to move photovoltaic panels in order to perform sun tracking. Primary importance is given to the search for a way to compensate sun–earth’s relative motions with two decoupled rotations of the panel. This leads to devise a kinematic structure characterized by a particular arrangement of the revolute axes. At the same time, the structure itself is designed in order to be slender. Subsequently, the fact that during a day the earth’s revolution around the sun has negligible effects on the apparent trajectory of the sun, if compared to the rotation around the polar axis, leads to choose a control strategy which, also thanks to the said arrangement of axes, employs only 1-DOF for most of the daytime. The tracker which employs this strategy has, theoretically, an energy consumption similar to that of 1-DOF solar trackers but a precision similar to that of 2-DOF ones.

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