Workspace Evaluation of Stewart Platforms

1992 ◽  
Author(s):  
Oren Masory ◽  
Jian Wang
Keyword(s):  
Stewart Platform ◽  
Design Tool ◽  
Kinematic Constraints ◽  
Stewart Platforms ◽  
Selection Of

Abstract The workspace and the dexterity of a Stewart Platform are effected by the choice of its major dimensions, actuators’ stroke and the kinematic constraints of its joints. An investigation of the effects of these parameters on workspace volume of the platform is presented. The obtained results were normalized so that these can be used as a design tool for the selection of dimensions, joints and actuators.

Dynamics Decomposition for Stewart Platforms

1994 ◽  
Vol 116 (1) ◽  
pp. 67-69 ◽  
Author(s):  
Zhiming Ji
Keyword(s):  
Dynamic Analysis ◽  
Driving Forces ◽  
Stewart Platform ◽  
Inertia Effect ◽  
Moving Plate ◽  
Stewart Platforms

This paper shows that special features of the Stewart platform can lead to the decomposition of the moving plate and the legs in the dynamic analysis. Formulas for evaluating, separately, the driving forces needed for the movement of the legs are developed for studying the combined inertia effect of all the leg rotations in a Stewart platform. The proposed formulation is easy to implement for Stewart platforms with nonnegligible leg inertia.

Algorithmic Selection of Preferred Grasp Poses using Manipulability Ellipsoid Forms

2021 ◽  
pp. 1-24
Author(s):  
Rajesh Kumar ◽  
Sudipto Mukherjee
Keyword(s):  
Geodesic Distance ◽  
Object Surface ◽  
Kinematic Constraints ◽  
Rolling Contacts ◽  
Manipulability Measure ◽  
Robotic Grasp ◽  
Selection Of

Abstract An algorithm to search for a kinematically desired robotic grasp pose with rolling contacts is presented. A manipulability measure is defined to characterise the grasp for multi-fingered robotic handling. The methodology can be used to search for the goal grasp pose with a manipulability ellipsoid close to the desired one. The proposed algorithm is modified to perform rolling based relocation under kinematic constraints of the robotic fingertips. The search for the optimal grasp pose and the improvement of the grasp pose by relocation is based on the reduction of the geodesic distance between the current and the target manipulability matrices. The algorithm also derives paths of the fingertip on the object surface in order to achieve the goal pose. An algorithmic option for the process of searching for a suitable grasp configuration is hence achieved.

Experimental Investigations on the Contour Generation of a Reconfigurable Stewart Platform

2013 ◽  
pp. 291-301
Author(s):  
G. Satheesh Kumar ◽  
T. Nagarajan
Keyword(s):  
Error Analysis ◽  
Natural Frequency ◽  
Vibration Isolation ◽  
Stewart Platform ◽  
Design Tool ◽  
Experimental Investigations ◽  
Variable Geometry ◽  
Optimum Geometry ◽  
Complete Set

Reconfiguration of Stewart platform for varying tasks accentuates the importance for determination of optimum geometry catering to the specified task. The authors in their earlier work (Satheesh et al., 2008) have indicated the non availability of an efficient holistic methodology for determining the optimum geometry. Further, they have proposed a solution using the variable geometry approach through the formulation of dimensionless parameters in combination with generic parameters like configuration and joint vector. The methodology proposed provides an approach to develop a complete set of design tool for any new reconfigurable Stewart platform for two identified applications viz., contour generation and vibration isolation. This paper details the experimental investigations carried out to validate the analytical results obtained on a developed Stewart platform test rig and error analysis is performed for contour generation. The experimental natural frequency of the developed Stewart platform has also been obtained.

scholarly journals A Unified Method for Computing Position and Orientation Workspaces of General Stewart Platforms

2011 ◽  
Author(s):  
Oriol Bohigas ◽  
Llui´s Ros ◽  
Montserrat Manubens
Keyword(s):  
Complex Shape ◽  
Three Dimensional ◽  
Stewart Platform ◽  
Large Dimension ◽  
Connected Components ◽  
Cartesian Space ◽  
Position And Orientation ◽  
Stewart Platforms ◽  
Orientation Workspace ◽  
Unified Method

The workspace of a Stewart platform is a complex six-dimensional volume embedded in the Cartesian space defined by six pose parameters. Because of its large dimension and complex shape, such workspace is difficult to compute and represent, so that comprehension on its structure is being gained by studying its three-dimensional slices. While successful methods have been given to determine the constant-orientation slice, the computation and appropriate visualization of the constant-position slice (also known as the orientation workspace) has proved to be a challenging task. This paper presents a unified method for computing both of such slices, and any other ones defined by fixing three pose parameters, on general Stewart platforms involving mechanical limits on the active and passive joints. Additional advantages over previous methods include the ability to determine all connected components of the workspace, and any motion barriers present in its interior.

scholarly journals Simulation of UAV Systems

10.14311/754 ◽  
2005 ◽  
Vol 45 (4) ◽  
Author(s):  
P. Kaňovský ◽  
L. Smrcek ◽  
C. Goodchild
Keyword(s):  
Dynamical System ◽  
Unmanned Aerial Vehicle ◽  
Low Cost ◽  
Design Tool ◽  
Inertial System ◽  
Principal Function ◽  
Low Weight ◽  
High Bandwidth ◽  
Aerial Vehicle ◽  
Selection Of

The study described in this paper deals with the issue of a design tool for the autopilot of an Unmanned Aerial Vehicle (UAV) and the selection of the airdata and inertial system sensors. This project was processed in cooperation with VTUL a PVO o.z. [1]. The feature that distinguishes the autopilot requirements of a UAV (Figs. 1, 7, 8) from the flight systems of conventional manned aircraft is the paradox of controlling a high bandwidth dynamical system using sensors that are in harmony with the low cost low weight objectives that UAV designs are often expected to achieve. The principal function of the autopilot is flight stability, which establishes the UAV as a stable airborne platform that can operate at a precisely defined height. The main sensor for providing this height information is a barometric altimeter. The solution to the UAV autopilot design was realised with simulations using the facilities of Matlab® and in particular Simulink®[2]. 

Research on Inverse Kinematic Design of a Certain Hydraulic Stewart Platform

2011 ◽  
Vol 58-60 ◽  
pp. 2442-2445
Author(s):  
Zhi Yong Qu ◽  
Zheng Mao Ye
Keyword(s):  
Machine Tools ◽  
Stewart Platform ◽  
Inverse Kinematic ◽  
Design And Optimization ◽  
Kinematic Design ◽  
Structural Rigidity ◽  
The Future ◽  
Stewart Platforms ◽  
Kinematic Loop ◽  
Motion Dynamics

Stewart platforms have recently attracted attention as simulator and machine tools because of their conceptual potentials in high motion dynamics and accuracy combined with high structural rigidity due to their closed kinematic loop. This paper, composed of inverse kinematic design and optimization, attempts to ground the foundation on dynamics design and choice in the future.

scholarly journals Creation of a Framework of Design Tool Characteristics to Support Evaluation and Selection of Visualisation Tools

2019 ◽  
Vol 1 (1) ◽  
pp. 1115-1124 ◽  
Author(s):  
Wenwen Zhang ◽  
Charlie Ranscombe ◽  
David Radcliffe ◽  
Simon Jackson
Keyword(s):  
Design Process ◽  
Design Tool ◽  
Design Tools ◽  
Tool Development ◽  
Design Practice ◽  
Use Of Resources ◽  
Comprehensive Framework ◽  
Support Evaluation ◽  
Selection Of

AbstractIn Industrial Design, new design visualisation tools are emerging offering significant benefits to the designers. However, studies show alongside some benefits, new tools can also inhibit designers' creativity or cause time inefficiency if used in the wrong context. Thus, understanding which tools to use and when during the design process is increasingly necessary to ensure the best use of resources in design practice. Existing research on understanding the performance of design tools and the resulting frameworks for comparing tools are either specific to certain tools or highly generalised making evaluation across different design tools challenging. As such, this paper reports the creation of a more comprehensive framework of design tool characteristics to facilitate a better understanding of design tools and their uses. Demonstration of application of the framework is also given in the form of a case study on the use of Digital Sketching and its comparable tools with four practising designers. In conclusion, we show how the Design Tool Characteristics (DTCs) framework is an effective way to understand design tools, with further implications for design tool development.

Synthesis and Experimental Validation of Dynamic Parts-Orienting Devices

1992 ◽  
Author(s):  
Inhwan Han ◽  
B. J. Gilmore ◽  
M. M. Ogot
Keyword(s):  
High Speed ◽  
Experimental Validation ◽  
Cost Effective ◽  
Design Tool ◽  
Kinematic Constraints ◽  
Dynamic Synthesis ◽  
Orientation Systems ◽  
Part Orientation ◽  
Impact With Friction ◽  
Synthesis Approach

Abstract Part orientation is an important aspect of factory automation. The parts-orienters presented by this paper are flexible to handle a variety of parts, passive (cost effective) and high-speed (i.e., include significant inertial effects). This paper presents a dynamic synthesis approach of gravity fed parts-orienters. In general, previous works were constrained by their quasi-static analyses. This research demonstrates the synthesis for dynamic parts-orienters based on the mechanics of the system using a simulation package as a design tool. The dynamic effects considered by this work include friction, inertial forces, impact with friction and contact/no-contact (changing kinematic constraints). The passive part orientation systems, which are developed by dynamic system synthesis in the presence of friction and impact, succeed in aligning a part into a specified orientation and through experiment are shown to be valid. This paper presents and experimentally validates a synthesis approach for dynamic mechanical systems with changing kinematic constraints. The experimental validation uses high speed video.

A VISUALIZATION AND DESIGN TOOL (AVID) FOR DATA MINING WITH THE SELF-ORGANIZING FEATURE MAP

2000 ◽  
Vol 09 (03) ◽  
pp. 369-375
Author(s):  
SUSAN E. GEORGE
Keyword(s):  
Neural Network ◽  
Data Mining ◽  
Software Tool ◽  
Design Tool ◽  
The Self ◽  
Training Data ◽  
Feature Map ◽  
Network Training ◽  
Som Network ◽  
Selection Of

This paper presents a software tool called AVID (A VIsualization and Design) which is particularly useful for data mining with an artificial neural network known as the self-organising feature map (SOM). AVID supports network training in both the i) selection of network inputs and ii) visualisation of the trained SOM. Both these features are novel aids to SOM network training and are particularly important when consideration is given to using the SOM for data mining. Once trained the SOM produces a 2-dimensional topological ordering of the input training data and it is particularly useful for representing the relationships within multi-dimensional data. The main classes within the data can be identified from the output map. AVID is an important software tool which enables data mining with the SOM by the selection of network inputs and the subsequent visualisation of the classes within these input vectors.

Experimental Investigations on the Contour Generation of a Reconfigurable Stewart Platform

2011 ◽  
Vol 1 (4) ◽  
pp. 87-99
Author(s):  
G. Satheesh Kumar ◽  
T. Nagarajan
Keyword(s):  
Error Analysis ◽  
Vibration Isolation ◽  
Stewart Platform ◽  
Design Tool ◽  
Experimental Investigations ◽  
Variable Geometry ◽  
Test Rig ◽  
Optimum Geometry ◽  
Complete Set

Reconfiguration of Stewart platform for varying tasks accentuates the importance for determination of optimum geometry catering to the specified task. The authors in their earlier work (Satheesh et al., 2008) have indicated the non availability of an efficient holistic methodology for determining the optimum geometry. Further, they have proposed a solution using the variable geometry approach through the formulation of dimensionless parameters in combination with generic parameters like configuration and joint vector. The methodology proposed provides an approach to develop a complete set of design tool for any new reconfigurable Stewart platform for two identified applications viz., contour generation and vibration isolation. This paper details the experimental investigations carried out to validate the analytical results obtained on a developed Stewart platform test rig and error analysis is performed for contour generation. The experimental natural frequency of the developed Stewart platform has also been obtained.

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