Modeling Uncertainty for Planar Meso-Scale Manipulation and Assembly

2006 ◽  
Author(s):  
David J. Cappelleri ◽  
Jonathan Fink ◽  
Vijay Kumar
Keyword(s):  
Manufacturing Industry ◽  
Surface Friction ◽  
Open Loop ◽  
Robotic Assembly ◽  
Planar Surface ◽  
Single Probe ◽  
Grasping And Manipulation ◽  
Static Operation ◽  
Series Of Experiments ◽  
Meso Scale

While robotic assembly at the centimeter and meter length scale is well understood and is routine in the manufacturing industry, robotic grasping and manipulation for meso-scale assembly at the millimeter and sub-millimeter length scales are much more difficult. This paper explores an possible way to manipulate and assemble planar parts using a micro-manipulator with a single probe capable of pushing parts on a planar surface with visual feedback. Specifically, we describe a study of the uncertainty associated with planar surface friction with a goal of developing a model of manipulation primitives that can be used for assembly. We describe a series of experiments and data analysis algorithms that allow us to identify the main system parameters for quasi-static operation, including the friction coefficient and the force distribution, while characterizing the uncertainty associated with these parameters. This allows us to bound the range of motions resulting from the uncertainty, which is necessary to design robust open-loop meso-scale manipulation and assembly motion plans.

Torsional Stiffness Improvement of a Soft Pneumatic Finger Using Embedded Skeleton

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Amin Lotfiani ◽  
Huichan Zhao ◽  
Zhufeng Shao ◽  
Xili Yi
Keyword(s):  
Torsional Stiffness ◽  
Good Precision ◽  
Pneumatic Actuators ◽  
Finite Element Approach ◽  
Grasping And Manipulation ◽  
Element Approach ◽  
Series Of Experiments ◽  
Soft Actuators ◽  
Compact Design ◽  
Rigid Skeleton

Abstract Silicone-based pneumatic actuators are among the most widely used soft actuators in adaptable fingers. However, due to the soft nature of silicone, the performance of these fingers is highly affected by the low torsional stiffness, which may cause failure in grasping and manipulation. To address this problem, a compact design is proposed by embedding a rigid skeleton into a soft pneumatic finger. A finite element approach with an analysical model is used to evaluate the performance of the fingers both with and without the skeleton. Then, a series of experiments is performed to study the bending motion and rigidity of the fingers. The results reveal that the skeleton increases the torsional stiffness of the finger up to 300%. Furthermore, the consistency with the experimental data indicates the good precision of the proposed modeling method. Finally, a two-finger hand is designed to evaluate the performance of the reinforced finger in reality. The grasp experiments illustrate that the hybrid finger with the skeleton is highly adaptable and can successfully grasp and manipulate heavy objects. Thus, a potential approach is proposed to improve the torsional stiffness of silicone-based pneumatic fingers while maintaining adaptability.

scholarly journals Modeling and control of planar slippage in object manipulation using robotic soft fingers

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Amin Fakhari ◽  
Imin Kao ◽  
Mehdi Keshmiri
Keyword(s):  
Dynamic Modeling ◽  
Surface Friction ◽  
Object Manipulation ◽  
Limit Surface ◽  
Modeling And Control ◽  
Grasping And Manipulation ◽  
And Control ◽  
Planar Contact ◽  
Soft Finger ◽  
Friction Limit Surface

Abstract Slippage occurrence has an important roll in stable and robust object grasping and manipulation. However, in majority of prior research on soft finger manipulation, presence of the slippage between fingers and objects has been ignored. In this paper which is a continuation of our prior work, a revised and more general method for dynamic modeling of planar slippage is presented using the concept of friction limit surface. Friction limit surface is utilized to relate contact sliding motions to contact frictional force and moment in a planar contact. In this method, different states of planar contact are replaced with a second-order differential equation. As an example of the proposed method application, dynamic modeling and slippage analysis of object manipulation on a horizontal plane using a three-link soft finger is studied. Then, a controller is designed to reduce and remove the undesired slippage which occurs between the soft finger and object and simultaneously move the object on a predefined desired path. Numerical simulations reveal the acceptable performance of the proposed method and the designed controller.

scholarly journals Torsional Stiffness Improvement of a Soft Pneumatic Finger Using Embedded Skeleton

2021 ◽  
pp. 1-1
Author(s):  
Amin Lotfiani ◽  
Huichan Zhao ◽  
Zhufeng Shao ◽  
Xili Yi
Keyword(s):  
Torsional Stiffness ◽  
Good Precision ◽  
Pneumatic Actuators ◽  
Finite Element Approach ◽  
Grasping And Manipulation ◽  
Element Approach ◽  
Series Of Experiments ◽  
Soft Actuators ◽  
Compact Design ◽  
Rigid Skeleton

Abstract Silicone-based pneumatic actuators are among the most widely used soft actuators in adaptable fingers. However, due to the soft nature of silicone, the performance of these fingers is highly affected by the low torsional stiffness, which may cause failure in grasping and manipulation. To address this problem, a compact design is proposed by embedding a rigid skeleton into a soft pneumatic finger. A finite element approach with an analytical model is used to evaluate the performance of the fingers both with and without the skeleton. Then, a series of experiments is performed to study the bending motion and rigidity of the fingers. The results reveal that the skeleton increases the torsional stiffness of the finger up to 300%. Furthermore, the consistency with the experimental data indicates the good precision of the proposed modeling method. Finally, a two-finger hand is designed to evaluate the performance of the reinforced finger in reality. The grasp experiments illustrate that the hybrid finger with the skeleton is highly adaptable and can successfully grasp and manipulate heavy objects. Thus, a potential approach is proposed to improve the torsional stiffness of silicone-based pneumatic fingers while maintaining adaptability.

Computational and Experimental Analysis of a Meso-Scale Heat Exchanger

1999 ◽  
Author(s):  
J. C. Sheu ◽  
M. G. Giridharan ◽  
S. H. Hong ◽  
R. Shekarriz ◽  
C. Call
Keyword(s):  
Heat Exchanger ◽  
Operating Conditions ◽  
Limiting Factors ◽  
Flow And Heat Transfer ◽  
Purification System ◽  
Successful Design ◽  
Flow Heat ◽  
Series Of Experiments ◽  
And Performance ◽  
Meso Scale

Abstract The main objective of this study is to develop an efficient meso-scale thermo-catalytic air purification system for battlefield applications. In this system, heated air is passed through a catalytic reactor to destroy toxic materials. The main constraints in designing this system are size, weight and fuel/power consumption. A successful design of this type of purification system depends to a large extent on the efficiency and performance of the heat exchanger. As a first step, a heat exchanger system that consists of several units of planar counter flow heat exchangers stacked on top of each other has been designed and fabricated. A CFD (Computational Fluid Dynamics) model has been used to understand the flow and heat transfer characteristics as well as to predict the effectiveness of the heat exchanger. A series of experiments have been performed to collect data to validate the CFD results. It will be shown that the data for temperature and effectiveness are in agreement with CFD predictions. Parametric simulations have also been performed to evaluate the heat exchanger performance as functions of geometric and operating conditions. The results indicate that axial conduction in the exchanger plate and the thermal boundary layer film resistance are the limiting factors in the heat exchanger performance.

scholarly journals Modeling and Compensation for Hysteresis Nonlinearity of a Piezoelectrically Actuated Fast Tool Servo Based on a Novel Linear Model

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Zhiwei Zhu ◽  
Xiaoqin Zhou ◽  
Jieqiong Lin ◽  
Qiang Liu
Keyword(s):  
Fractional Calculus ◽  
Linear Model ◽  
Fractional Order ◽  
Analytical Description ◽  
Open Loop ◽  
Fast Tool Servo ◽  
Compensation Strategy ◽  
Hysteresis Nonlinearity ◽  
Series Of Experiments ◽  
Compensation Approach

In order to describe and compensate for complex hysteresis nonlinearities of piezoelectrically actuated fast tool servo (FTS), a novel Linear Fractional order Differentiation Hysteresis (LFDH) model is proposed in this paper. By means of the proposed LFDH model which is established on the fractional calculus theory, an analytical description of hysteresis behaviors of the FTS is derived. Furthermore, the LFDH model-based inverse compensation strategy is proposed to suppress the hysteresis effects of the FTS. Finally, a series of experiments are conducted to verify the effectiveness of the LFDH model and the corresponding compensation approach. The results demonstrate that the proposed LFDH model is efficient for describing hysteresis behaviors and the inverse compensation strategy can significantly suppress the inherent hysteresis of the FTS in open-loop operations.

A model and strategy analysis of the peg-hole system in the search process associated with robotic assembly operations without chamfers

Robotica ◽  
1996 ◽  
Vol 14 (6) ◽  
pp. 647-658 ◽  
Author(s):  
Hong Qiao ◽  
Philip Moore ◽  
Jeff Knight
Keyword(s):  
High Precision ◽  
Manufacturing Process ◽  
High Speed ◽  
Manufacturing Industry ◽  
Robotic Assembly ◽  
Search Process ◽  
Strategy Analysis ◽  
Assembly Operation ◽  
Assembly Operations ◽  
Insertion Process

Robotic peg-hole insertion operations can play a very important role in manufacturing industry because it is a common requirement in the manufacturing process and, it requires high precision and high speed.In general, this operation can be divided into two processes: Search process to engage the peg and the hole and, insertion process.The search process is critical in the assembly operation. It can be defined as a process where the angular.and the translational errors between the peg and the hole are reduced until insertion can occur.

Learning Task Strategies in Robotic Assembly Systems

Robotica ◽  
1992 ◽  
Vol 10 (5) ◽  
pp. 409-418 ◽  
Author(s):  
D. S. Ahn ◽  
H. S. Cho ◽  
K. Ide ◽  
F. Miyazaki ◽  
S. Arimoto
Keyword(s):  
Learning Algorithm ◽  
Functional Limitations ◽  
Practical Method ◽  
Learning Task ◽  
Robotic Assembly ◽  
Task Execution ◽  
Force Signal ◽  
Imperfect Knowledge ◽  
Series Of Experiments ◽  
Task Strategies

SUMMARYThis paper presents a practical method for generating task strategies applicable to chamferless and high-precision assembly. The difficulties in devising reliable assembly strategies result from various forms of uncertainty such as imperfect knowledge on the parts being assembled and functional limitations of the assembly devices.In order to cope with these problems, the robot is provided with the capability of learning the corrective motion in response to the force signal through iterative task execution. The strategy is realized by adopting a learning algorithm and is represented in a binary tree-type database. To verify the effectiveness of the proposed algorithm, a series of experiments are carried out under simulated real production conditions. The experimental results show that sensory signal-to-robot action mapping can be acquired effectively and, consequently, the assembly task can be performed successfully.

scholarly journals Use of Ultra Wide Band Real-Time Location System on Construction Jobsites: Feasibility Study and Deployment Alternatives

2020 ◽  
Vol 17 (7) ◽  
pp. 2219
Author(s):  
Waleed Umer ◽  
Mohsin K. Siddiqui
Keyword(s):  
Real Time ◽  
Manufacturing Industry ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Small Scale ◽  
Construction Sites ◽  
Average Accuracy ◽  
Series Of Experiments ◽  
The Impact ◽  
Level Of Effort

Ultra wide band (UWB)-based real-time location systems (RTLSs) have been widely adopted in the manufacturing industry for tracking tools, materials, and ensuring safety. Researchers in the construction domain have investigated similar uses for UWB-based RTLSs on construction jobsites. However, most of these investigations comprised small-scale experiments using average accuracy only to demonstrate use cases for the technology. Furthermore, they did not consider alternative deployment scenarios for practically feasible deployment of the technology. To overcome these limitations, a series of experiments were performed to study the feasibility of a commercially available RTLS on the construction jobsites. The focus of the work was on feasibility in terms of accuracy analysis of the system for a large experimental site, the level of effort requirements for deployment, and the impact of deployment alternatives on the accuracy of the system. The results found that average accuracy was found to be a misleading indicator of the perceived system performance (i.e., 95th percentile values were considerably higher than average values). Moreover, accuracy is significantly affected by the deployment alternatives. Collectively, the results arising from the study could help construction/safety managers in decision making related to the deployment of UWB-based RTLSs for their construction sites.

scholarly journals V. Similarity of motion in relation to the surface friction of fluids

1914 ◽  
Vol 214 (509-522) ◽  
pp. 199-224 ◽  
Keyword(s):  
General Relation ◽  
Surface Friction ◽  
The Body ◽  
Thin Plates ◽  
Flat Plates ◽  
Series Of Experiments ◽  
The Subject ◽  
Different Dimensions ◽  
Laws Of Motion ◽  
A Current

The laws of the surface friction of fluids have formed the subject of many important investigations during the last 100 years, among which may be mentioned the work of Poiseuille, Darcy and Osborne Reynolds on the friction of water flowing in pipes, that of William Froude on the resistance of thin plates towed in water, and the corresponding experiments of Zahm on flat plates in a current of air. Researches in this field have also been carried out by Brix, Stockalper, Mallock, Coker, Gebers, Brightmore, Grindley and Gibson, and others. As a result, the effect on the resistance, of the dimensions of the body over whose surface the fluid moves, and of the velocity of flow, are tolerably well known for the particular fluid and character of motion observed. In the case of the surface friction of water in pipes, the researches of Osborne Reynolds have demonstrated the existence of similar motions in pipes of different dimensions, hut, as far as the authors are aware, no systematic series of experiments appears to have been made for the purpose of establishing a general relation which would be applicable to all fluids and conditions of flow, although the existence of such relationships for different aspects of the problem were predicted as a consequence of the laws of motion by Stokes in 1850, by Helmholtz in 1873, by Osborne Reynolds in 1882, by Lord Rayleigh in 1899 and 1909, and as has been pointed out by Sir George Greenhill, were foreshadowed by Newton in Proposition 32, Book II., of the ‘Principia.’

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