A Passive Compliant Wrist Design for Robot Manipulators

1998 ◽  
Author(s):  
Christopher D. Hoffman ◽  
A. H. Soni ◽  
David F. Thompson
Keyword(s):  
Manufacturing Systems ◽  
Assembly Line ◽  
Motion Simulation ◽  
End Effector ◽  
Dynamic Motion ◽  
Novel Approach ◽  
Robot Accuracy ◽  
Final Design ◽  
Initial Idea ◽  
Earthquake Protection

Abstract Robot assembly in manufacturing systems is still a work-intensive process. A main difficulty that arises when trying to automate an assembly task with a robot is the precision required to position and orient the parts. This difficulty arises in several sources of error, such as robot accuracy, the gripping and presentation precision of pieces, and part tolerance. High requirements for part insertion also present a greater possibility for jamming of parts and bottlenecking of the assembly line. Using a compliant device mounted between the end effector of the robot and the gripper mechanism may relieve this situation. In order to achieve the reality of cheaper automation solutions by using robots in high precision insertion tasks, a passive compliant gripper device would need to be used. A passive design would supply the user with a “bolt-on” device that did not require any extra controllers or interfacing between the compliant wrist and the robot main controller, as is the case with an active or hybrid design. Using the wrist in operation, the number of damaged parts and the number of crashes by the robot would be reduced. Other compliant devices that are currently offered by commercial companies are compared with the proposed design and debated. After a study of existing compliant devices, a novel approach is presented. Utilizing an earthquake protection device for buildings as an initial idea fountain, a new compliant wrist design is formulated. The Passive Compliant Wrist design, based on a building support system, is exhibited in detail. A comprehensive discussion of the wrist in operation is also presented. The final design has also been verified using the dynamic motion simulation program, Working Model, by Knowledge Revolution.

On-the-Fly Substrate Eccentricity Recognition for Robotized Manufacturing Systems

2005 ◽  
Vol 127 (1) ◽  
pp. 206-216 ◽  
Author(s):  
Martin Hosek ◽  
Jan Prochazka
Keyword(s):  
Optical Sensors ◽  
Semiconductor Manufacturing ◽  
Manufacturing Systems ◽  
Robotic Manipulator ◽  
End Effector ◽  
Transfer Path ◽  
The Difference ◽  
Manufacturing Applications ◽  
Actual Location

This paper describes a method for on-the-fly determination of eccentricity of a circular substrate, such as a silicon wafer in semiconductor manufacturing applications, carried by a robotic manipulator, where eccentricity refers to the difference between the actual location of the center of the substrate and its desired position on the end-effector of the robotic manipulator. The method utilizes a pair of external optical sensors located along the substrate transfer path. When moving a substrate along the transfer path, the robotic manipulator captures the positions and velocities of the end-effector at which the edges of the substrate are detected by the sensors. These data along with the expected radius of the substrate and the coordinates of the sensors are used to determine the eccentricity of the substrate. This information can be used by the robotic manipulator to compensate for eccentricity of the substrate when performing a place operation, resulting in the substrate being placed centered regardless of the amount and direction of the initial eccentricity. The method can also be employed to detect a defect, such as breakage, of a circular substrate and report an error condition which can abort or otherwise adjust operation of the robotic manipulator.

scholarly journals Modeling and Experimental Design for the On-Orbit Inertial Parameter Identification of Free-Flying Space Robots

2005 ◽  
Author(s):  
Roberto Lampariello ◽  
Gerhard Hirzinger
Keyword(s):  
Energy Consumption ◽  
Experimental Design ◽  
Parameter Identification ◽  
Suitable Model ◽  
Space Robots ◽  
Full System ◽  
End Effector ◽  
Dynamic Motion ◽  
Inertial Parameters ◽  
Flying Robot

A method is proposed for the identification of the inertial parameters of a free-flying robot directly in orbit, using accelerometers. This can serve to improve the path planning and tracking capabilities of the robot, as well as its efficiency in energy consumption. The method is applied to the identification of the base body and of the load on the end-effector, giving emphasis to the experimental design. The problem of the identification of the full system is also addressed in its theoretical aspects. The experience from the Getex Dynamic Motion experiments performed on the ETS-VII satellite have allowed to determine a most suitable model for the identification.

Task Planning of Assembly of Flexible Objects and Vision-Based Verification

Robotica ◽  
1998 ◽  
Vol 16 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Jun Miura ◽  
Katsushi Ikeuchi
Keyword(s):  
Manufacturing Systems ◽  
Action Planning ◽  
Assembly System ◽  
Automated Manufacturing ◽  
Laser Range Finder ◽  
Automated Manufacturing Systems ◽  
Laser Range ◽  
Novel Approach ◽  
Rubber Belt ◽  
Flexible Objects

The ability of manipulating flexible objects, such as rubber belts and paper sheets, is important in automated manufacturing systems. This paper describes a novel approach to vision-guided assembly of flexible objects. The operation dealt with in this paper is to assemble a rubber belt with fixed pulleys. By analyzing possible states of the belt based on the empirical knowledge of the belt, we can derive a method to have not only the action planning but also the visual verification planning. We have implemented a belt assembly system using the two manipulators and a laser range finder as the sensor, and succeeded in performing the belt-pulley assembly. The extension of our approach to other kinds of assembly of flexible objects is also discussed.

A Novel Perspective in the Design of Cable-Driven Systems

2008 ◽  
Author(s):  
Giulio Rosati ◽  
Damiano Zanotto
Keyword(s):  
Systems Design ◽  
The Novel ◽  
End Effector ◽  
New Approach ◽  
Driven Systems ◽  
Working Space ◽  
Novel Approach ◽  
Workspace Analysis ◽  
Workspace Optimization ◽  
Novel Design

This paper deals with a novel approach to the design of cable-driven systems. This kind of robots possesses several desirable features that distinguish them from common manipulators, such as: low-inertia, cost-effectiveness, safety, easy reconfiguration and transportability. One key-issue that arises from the unilateral actuation is the design for workspace optimization. Most previous researches on cable-driven systems design focused their attention on workspace analysis for existing devices. Conversely, we introduce a new approach for improving workspace by design, introducing movable pulley-blocks rather than increasing the number of cables. By properly moving the pulley-blocks, the end-effector can be always maintained in the best part of the working space, thus enhancing robot capabilities without the need for additional cables. Furthermore, the eventuality of cable interference is strongly reduced. In this paper, the novel design concept is applied to different planar point-mass cable-driven robots, with one or more translating pulley-blocks. The maximum feasible isotropic force, along with the power dissipation and the effective mass at the end-effector are employed to compare the performances of different configurations.

Assembly Line Balancing Type-2 Using Unequal Multiple Operators

2013 ◽  
Vol 816-817 ◽  
pp. 1169-1173
Author(s):  
Usman Attique ◽  
Abdul Ghafoor ◽  
Riaz Ahmed ◽  
Shahid Ikramullah
Keyword(s):  
Cycle Time ◽  
Assembly Line ◽  
Assembly Line Balancing ◽  
Computational Effort ◽  
Line Balancing ◽  
Heuristic Methods ◽  
Novel Approach ◽  
Assembly Line Balancing Problem

Various exact and heuristic methods have been proposed for assembly line balancing problem (ALBP) but unequal multiple operators have not been considered much. In this paper we present a novel approach of assembly line balancing Type-2 with unequal multiple operators by using an already developed code in Matlab (Tomlab modeling platform). The adopted approach can be applied at line balancing problems ranging from few to hundreds of work elements to achieve minimum cycle time with very less computational effort.

Motion Simulation of a Hybrid Parallel Robot for Ankle Rehabilitation

2014 ◽  
Author(s):  
Hamid Rakhodaei ◽  
Mozafar Saadat ◽  
Alireza Rastegarpanah
Keyword(s):  
Parallel Robot ◽  
Hybrid Structure ◽  
Inverse Kinematic ◽  
Motion Simulation ◽  
Stroke Patients ◽  
End Effector ◽  
Ankle Rehabilitation ◽  
Motion Paths ◽  
Experimental Values ◽  
Forward Kinematic

This paper addresses the path planning of a hybrid parallel robot for ankle rehabilitation. The robot contains 3-DOF parallel mechanism that is attached on top of the 6-DOF hexapod. The 6-UPU-3-UPR parallel robot is developed to simulate ankle motions for the rehabilitation of post-stroke patients with an affected ankle. The inverse kinematic of hybrid parallel robot is developed in order to track the end-effector’s position through Matlab software. The calculated stroke size of each actuator is imported to apply the forward kinematic for determining the position of end-effector. The experimental and simulation values of the hexapod are compared with those of the hybrid structure through a number of exercise motion paths. The results reveal that, in general, the simulation values follow well the experimental values, although with different degrees of variation for each of the structures considered.

Assembly Configuration Synthesis Method for Discretely-Actuated Manipulators

2006 ◽  
Author(s):  
Deanne C. Kemeny ◽  
Raymond J. Cipra
Keyword(s):  
Synthesis Method ◽  
Specific Element ◽  
End Effector ◽  
Novel Approach ◽  
Serial Chain ◽  
Synthesis Strategy ◽  
Planar Grid ◽  
Three Stages ◽  
Configuration Synthesis ◽  
Unique Application

Discretely-actuated manipulators are defined in this paper as serial planar chains of many links where the actuation of one link with respect to the previous link occurs in one of three discrete positions. Because of the limited end-effector workspace, a link may be manually connected to the previous link in one of four 90° orientations to assist in generating a workspace corresponding to specific applications. Given an application workspace, the assembly configuration synthesis strategy presented here is a novel approach to determine the nominal configuration (all actuators in their 0° position) of the serial chain. The solved configuration will cover an application grid area using its discrete actuation with no change in nominal configuration. The unique application workspace, defined as a planar grid area, requires the end effector to be positioned somewhere within each specific element of the grid. The synthesis strategy is made up of three stages with each stage having tests that increase in computation and difficulty that a potential configuration must pass or be eliminated. Critical to the tests is the ability to quickly model and approximate the end-effector workspace of a configuration and a new method for this approximation is described.

Scheduling Flexible Manufacturing Systems with Petri Nets Based on the Cell Enumeration Method

2011 ◽  
Vol 346 ◽  
pp. 412-418
Author(s):  
Shen Shen Gu
Keyword(s):  
Petri Net ◽  
Flexible Manufacturing ◽  
Flexible Manufacturing Systems ◽  
Manufacturing Systems ◽  
Fundamental Equation ◽  
Reachability Analysis ◽  
Integer Solution ◽  
Vector Solution ◽  
Novel Approach ◽  
Cell Enumeration

In the field of modern manufacturing, flexible manufacturing systems (FMS) is very important because it can scheduleand optimize multipurpose machines to produce multiple types of products. When applying the FMS technology, Petri Net is used to model the machines, parts and the whole manufacturing progress. The core concern of FMS is to make sure that the manufacturing system can transfer from the original state to the final state, which is called reachabilty. Therefore, reachability analysis is one of the most important problems of FMS. When Petri Net is acyclic, the reachability analysis can be performed by finding a integer solution to a set of linear equation, named fundamental equation, which is known to be NP-complete. In this paper, a novel approach for finding the integer solution is applied by adopting a revised version of the cell enumeration method for an arrangement of hyperplanes in discrete geometry to identify firing count vector solution(s) to the fundamental equation on a bounded integer set with a complexity bound of O((nu)n¡m),where n is the number of nodes, m is the number of arcs and u is the upper bound of the number of firings for all individual arcs.

Sign in / Sign up

Export Citation Format

Share Document