A Deterministic Method of Application Region of Clamping Forces for Fixture Design

2011 ◽  
Vol 697-698 ◽  
pp. 345-348
Author(s):  
X.Y. Guo ◽  
Guo Hua Qin ◽  
Hai Chao Ye
Keyword(s):  
Screw Theory ◽  
Deterministic Algorithm ◽  
Fixture Design ◽  
Clamping Force ◽  
Discretization Method ◽  
Deterministic Method ◽  
Analysis Algorithm ◽  
Production Safety ◽  
Workpiece Stability

After being located, cutting force and torques will exert on a workpiece during the machining operation. In order to guarantee the location accuracy and production safety, the feasible clamping forces must be planned to stabilize the workpiece in the entire processing. Therefore, the workpiece stability is taken as a core to create a deterministic algorithm to the application region of clamping forces for the complex workpiece. Firstly, on the basis of the combination of the screw theory with the linear programming technology, an analysis algorithm is subjected to judge the workpiece stability. Secondly, according to the surface discretization method, a deterministic algorithm is further established to plan the application region of clamping force by analyzing the workpiece stability at all nodes in sequence. The proposed method can be utilized for the determination of the application region of clamping forces as well as the verification of the feasibility of the magnitudes of clamping forces.

Geometric and Kinetic Model Based Computer-Aided Fixture Design Verification

2003 ◽  
Vol 3 (3) ◽  
pp. 187-199 ◽  
Author(s):  
Y. Kang ◽  
Y. Rong ◽  
J. A. Yang
Keyword(s):  
Kinetic Model ◽  
Kinetic Models ◽  
Fixture Design ◽  
Clamping Force ◽  
Design Verification ◽  
Modular Fixtures ◽  
Computer Aided ◽  
Machining Operations ◽  
Tolerance Assignment

Computer-aided fixture design (CAFD) techniques have advanced to the point that fixture configurations can be generated automatically, for both modular fixtures and dedicated fixtures. Computer-aided fixture design verification (CAFDV) is a technique for verifying and improving existing fixture designs. This paper introduces a first comprehensive CAFDV framework which uses both geometric and kinetic models to verify locating completeness, locating accuracy, and fixturing stability. The models can be also used for locating tolerance assignment and the determination of minimum clamping force required in machining operations. The system is integrated with commercial CAD package and applied in industrial real-cases.

Convergence Study on Application of the Over-Deterministic Method for Determination of Near-Tip Fields in a Cracked Plate Loaded in Mixed-Mode

2012 ◽  
Vol 249-250 ◽  
pp. 76-81 ◽  
Author(s):  
Lucie Šestáková ◽  
Václav Veselý
Keyword(s):  
Mixed Mode ◽  
Brittle Materials ◽  
Higher Order ◽  
Displacement Fields ◽  
Deterministic Method ◽  
Crack Behavior ◽  
Stress And Displacement Fields ◽  
Higher Order Terms ◽  
Convergence Study

Multi-parameter description of crack behavior in quasi-brittle materials offers still enough space for investigations. Several studies have been carried out by the authors in this field [1-3]. One part of the publications by the authors (this work included) contain analyses of the accuracy, convergence and/or tuning of the over-deterministic method that enables determination of the coefficients of the higher-order terms in Williams expansion approximating the stress and displacement fields in a cracked body without any complicated FE formulations. These intermediate studies should bring together a list of recommendations how to use the ODM as effectively as possible and obtain reliable enough values of coefficients of the higher-order terms. Thus, the stress/displacement field can be determined precisely even in a larger distance from the crack tip, which is crucial for assessment of the fracture occurring in quasi-brittle materials.

Determination of contact points between workpiece and fixture elements as a tool for augmented reality in fixture design

2019 ◽  
Author(s):  
Vitalii Ivanov ◽  
Ivan Pavlenko ◽  
Oleksandr Liaposhchenko ◽  
Oleksandr Gusak ◽  
Vita Pavlenko
Keyword(s):  
Augmented Reality ◽  
Fixture Design ◽  
Contact Points

Iterative Fixture Layout and Clamping Force Optimization Using the Genetic Algorithm

2001 ◽  
Vol 124 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Krishnakumar Kulankara ◽  
Srinath Satyanarayana ◽  
Shreyes N. Melkote
Keyword(s):  
Genetic Algorithm ◽  
Nonlinear Programming ◽  
Primary Objective ◽  
Fixture Design ◽  
Clamping Force ◽  
Optimal Solutions ◽  
Fixture Layout ◽  
Force Optimization ◽  
Nonlinear Programming Methods ◽  
Objective Being

Fixture design is a critical step in machining. An important aspect of fixture design is the optimization of the fixture, the primary objective being the minimization of workpiece deflection by suitably varying the layout of fixture elements and the clamping forces. Previous methods for fixture design optimization have treated fixture layout and clamping force optimization independently and/or used nonlinear programming methods that yield sub-optimal solutions. This paper deals with application of the genetic algorithm (GA) for fixture layout and clamping force optimization for a compliant workpiece. An iterative algorithm that minimizes the workpiece elastic deformation for the entire cutting process by alternatively varying the fixture layout and clamping force is proposed. It is shown via an example of milling fixture design that this algorithm yields a design that is superior to the result obtained from either fixture layout or clamping force optimization alone.

A Mathematical Approach to Automatic Configuration of Machining Fixtures: Analysis and Synthesis

1989 ◽  
Vol 111 (4) ◽  
pp. 299-306 ◽  
Author(s):  
Y-C. Chou ◽  
V. Chandru ◽  
M. M. Barash
Keyword(s):  
Screw Theory ◽  
Theory Analysis ◽  
Workpiece Surface ◽  
3 Dimensional ◽  
Prismatic Parts ◽  
Analysis And Synthesis ◽  
Engineering Mechanics ◽  
Machining Fixtures ◽  
Machining Operations

Drawing on screw theory and engineering mechanics, a mathematical theory for automatic configuration of machining fixtures for prismatic parts is developed. There are two parts in the theory: analysis and synthesis. The following functions of fixtures are analyzed: deterministic workpiece location, clamping stability, and total restraint. The synthesis of fixtures includes the determination of locating and clamping points on workpiece surface and the determination of clamping forces. The theory deals with the general case of 3-dimensional parts, polygon support (as opposed to three-point support), and multiple machining operations.

scholarly journals Vehicle Relocation Triggering Thresholds Determination in Electric Carsharing System under Stochastic Demand

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Wanjing Ma ◽  
Lei Wang ◽  
Lin Li
Keyword(s):  
Stochastic Method ◽  
Pareto Optimum ◽  
Deterministic Method ◽  
Stochastic Demands ◽  
State Transition Model ◽  
System States ◽  
Proper Values ◽  
Dual Objectives ◽  
Survey Comparison

Vehicle unbalance usually occurs in multistation electric carsharing systems. Threshold triggering method is one of the most practicable approaches for vehicle relocation, while determination of thresholds has not been sufficiently studied particularly for electric carsharing system. This paper presents an approach on determining the thresholds considering the stochastic demands and system states. Firstly, we establish a state transition model involving the stochastic variables to capture the dynamics of the number and battery status of vehicles as well as the traffic demands. Consequently, a dual-objective optimization model was developed to determine the proper values of thresholds. The solution algorithm employed the min–max robust optimization to tackle the uncertainty and the Pareto optimum to decide the solution under dual objectives. To test the distribution stochastic variables, we involve the orders data and the supplementary user survey. Comparison is conducted among three methods: the empirical rules, the deterministic method, and the stochastic method, where the results suggest that the stochastic method achieves better solutions on the dual objectives under stochastic demands.

Automatic inference on stable robotic assembly sequences based upon the evaluation of base assembly motion instability

Robotica ◽  
1993 ◽  
Vol 11 (4) ◽  
pp. 351-362 ◽  
Author(s):  
D.Y. Cho ◽  
C.K. Shinf ◽  
H.S. Chot
Keyword(s):  
Robotic Assembly ◽  
Fixture Design ◽  
Assembly Sequence ◽  
Inference Method ◽  
New Approach ◽  
Assembly Sequences ◽  
Crucial Information ◽  
Part Motion ◽  
Selection Of

SUMMARYThe consideration of part motion instability is crucial to the determination of assembly sequence since this affects the complexity of fixtures and dexterity of robots. This paper presents a new approach to the inference of robotic assembly sequences, taking into consideration the instability of base assembly motions. Based upon the evaluation of motion instability, the method generates stable assembly sequences by use of the precedence constraint inference method previously developed by the authors. An example assembly of a 10-part electrical relay is given to illustrate the concepts and procedure of the proposed scheme. The results show that the proposed method can be effectively utilized to generate stable assembly sequences, thus providing crucial information on the fixture design and selection of types of assembly robots.

scholarly journals Probabilistic-Deterministic Method of Rescaling Ship Manoeuvring Simulation Data Defining Parameters of Fairway Bends

2018 ◽  
Vol 1 (1) ◽  
pp. 127-133
Author(s):  
Stanisław Gucma ◽  
Rafał Gralak
Keyword(s):  
Accurate Determination ◽  
Scaling Up ◽  
Maximum Length ◽  
Deterministic Method ◽  
Simulation Data ◽  
Ship Manoeuvring

Abstract The article presents a method of scaling up existing simulation tests results from ships with parameters L1, B1 (length and breadth) determining a safe waterway bend width (d1) to specify a width (d2) safe for ships with other dimensions L2, B2. This method enables accurate determination of the safe fairway width (d) in case it has been planned to increase maximum length and width of vessels without carrying out relatively expensive simulation tests. The method was used in designing the parameters of the modernized Swinoujscie-Szczecin fairway.

A Direct Determination of the Instantaneous Kinematics of Fully Parallel Robot Manipulators

1985 ◽  
Vol 107 (2) ◽  
pp. 226-229 ◽  
Author(s):  
M. G. Mohamed ◽  
J. Duffy
Keyword(s):  
Screw Theory ◽  
Robot Manipulators ◽  
Direct Determination ◽  
Parallel Robot ◽  
End Effector ◽  
Actuated Joints ◽  
Parallel Type

Screw theory is applied to the study of the instantaneous kinematics of the end-effector platform of fully parallel robot type devices. The instantaneous motion of the end-effector is expressed directly in terms of the twists of the input-actuated joints and it is demonstrated that the twist representing the instantaneous motion of the end-effector platform is equal to the sum of its partial twists. A partial twist is defined as the twist representing the instantaneous motion of the end-effector when all but one of the input actuators are locked. The analysis presented forms a proper basis for the study of special configurations of parallel type devices.

Sign in / Sign up

Export Citation Format

Share Document