scholarly journals An Integrated Compensation Method for the Force Disturbance of a Six-Axis Force Sensor in Complex Manufacturing Scenarios

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4706
Author(s):  
Lei Yao ◽  
Qingguang Gao ◽  
Dailin Zhang ◽  
Wanpeng Zhang ◽  
Youping Chen
Keyword(s):  
Least Squares Method ◽  
Zero Point ◽  
Force Sensor ◽  
Compensation Method ◽  
Contact Forces ◽  
Active Compliance ◽  
High Measurement ◽  
Deep Learning Network ◽  
Robust Compensation ◽  
Human Robot Collaboration

As one of the key components for active compliance control and human–robot collaboration, a six-axis force sensor is often used for a robot to obtain contact forces. However, a significant problem is the distortion between the contact forces and the data conveyed by the six-axis force sensor because of its zero drift, system error, and gravity of robot end-effector. To eliminate the above disturbances, an integrated compensation method is proposed, which uses a deep learning network and the least squares method to realize the zero-point prediction and tool load identification, respectively. After that, the proposed method can automatically complete compensation for the six-axis force sensor in complex manufacturing scenarios. Additionally, the experimental results demonstrate that the proposed method can provide effective and robust compensation for force disturbance and achieve high measurement accuracy.

scholarly journals Simulation Verification of the Contact Parameter Influence on the Forces’ Course of Cereal Grain Impact against a Stiff Surface

2021 ◽  
Vol 11 (2) ◽  
pp. 466
Author(s):  
Włodzimierz Kęska ◽  
Jacek Marcinkiewicz ◽  
Łukasz Gierz ◽  
Żaneta Staszak ◽  
Jarosław Selech ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Decisive Role ◽  
Force Sensor ◽  
Contact Forces ◽  
Correct Selection ◽  
Contact Parameter ◽  
Cereal Grain ◽  
Wide Range ◽  
The Impact ◽  
Selection Of

The continuous development of computer technology has made it applicable in many scientific fields, including research into a wide range of processes in agricultural machines. It allows the simulation of very complex physical phenomena, including grain motion. A recently discovered discrete element method (DEM) is used for this purpose. It involves direct integration of equations of grain system motion under the action of various forces, the most important of which are contact forces. The method’s accuracy depends mainly on precisely developed mathematical models of contacts. The creation of such models requires empirical validation, an experiment that investigates the course of contact forces at the moment of the impact of the grains. To achieve this, specialised test stations equipped with force and speed sensors were developed. The correct selection of testing equipment and interpretation of results play a decisive role in this type of research. This paper focuses on the evaluation of the force sensor dynamic properties’ influence on the measurement accuracy of the course of the plant grain impact forces against a stiff surface. The issue was examined using the computer simulation method. A proprietary computer software with the main calculation module and data input procedures, which presents results in a graphic form, was used for calculations. From the simulation, graphs of the contact force and force signal from the sensor were obtained. This helped to clearly indicate the essence of the correct selection of parameters used in the tests of sensors, which should be characterised by high resonance frequency.

Kontaktkräfte beim ungeführten Vibrationsgleitschleifen*/Contact forces in unguided vibratory finishing

2015 ◽  
Vol 105 (06) ◽  
pp. 377-383
Author(s):  
F. Klocke ◽  
R. Brocker ◽  
F. Vits ◽  
P. Mattfeld
Keyword(s):  
Measurement System ◽  
Electrical Power ◽  
Force Sensor ◽  
Contact Forces ◽  
Work Piece ◽  
Data Logging ◽  
Vibratory Finishing ◽  
Revolution Speed ◽  
Measurement Results ◽  
Finishing Processes

Beim Vibrationsgleitschleifen wird der Werkstoffabtrag maßgeblich durch die vorherrschenden Kontaktkräfte zwischen dem Werkstück und den Schleifkörpern bestimmt. Dieser Fachartikel stellt ein Messsystem vor, mit dem die messtechnische Erfassung der Kontaktkräfte beim ungeführten Vibrationsgleitschleifen möglich ist. Ein Alleinstellungsmerkmal ist dabei die vollständig kabellose Ausführung des Messsystems. Somit wurden die Messergebnisse nicht durch Kabel beeinflusst, die üblicherweise für die Energieversorgung und Datenübertragung notwendig sind. Mithilfe dieses Messsystems wurde der Einfluss folgender Prozesseingangsgrößen systematisch untersucht: Schleifkörpergröße, Unwuchtmotordrehzahl, Versatzwinkel der Unwuchtgewichte sowie die Masse des unteren und oberen Unwuchtgewichts auf die Kontaktkräfte.   In vibratory finishing the material removal is influenced by the contact forces between work piece and media. In this paper a measurement system is presented which is able to measure contact forces between work piece and media in unguided vibratory finishing. The unique feature of the measurement system is its completely wireless construction so that the measurement results are not influenced by wires of the force sensor system including the electrical power supply and the data logging. By means of this measurement system, contact forces can be measured in unguided vibratory finishing processes for the first time. Furthermore, the influence of media size and adjustment of the unbalance motor like revolution speed, phase angle and mass distribution between the upper and the lower eccentric weight on the contact forces was investigated.

Semiparametric Regression Analysis on the AB Data with Zero-Point Drift

2014 ◽  
Vol 568-570 ◽  
pp. 227-232
Author(s):  
Yuan Tian ◽  
Jie Luo
Keyword(s):  
Least Squares Method ◽  
Simulation Analysis ◽  
Semiparametric Regression ◽  
Zero Point ◽  
Filter Method ◽  
Best Linear Unbiased Estimator ◽  
Penalized Least Squares ◽  
Semiparametric Regression Model ◽  
Semiparametric Method ◽  
Best Linear Unbiased

To deal with the AB data with zero-point drift, Swanson and Schlamminger have proposed a filter method to remove the drift of any desired polynomial order, and then give the best linear unbiased estimator of the observable, on the condition that the order of drift is known. Since this method directly removes the drift, one can not know the tendency of the systematic error. This paper proposes to construct a semiparametric regression model for the data, and then take the penalized least squares method to estimate the observable and the drift tendency simultaneously. Simulation analysis shows that the semiparametric method can reach the same accuracy of the filter method, and the estimation of the drift fits well with its actual value.

scholarly journals Development and Application of a Tandem Force Sensor

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6042
Author(s):  
Zhijian Zhang ◽  
Youping Chen ◽  
Dailin Zhang
Keyword(s):  
Contact Force ◽  
Mechanical Model ◽  
Traction Force ◽  
Force Sensor ◽  
Teaching Experiment ◽  
Contact Forces ◽  
Contact Tasks

In robot teaching for contact tasks, it is necessary to not only accurately perceive the traction force exerted by hands, but also to perceive the contact force at the robot end. This paper develops a tandem force sensor to detect traction and contact forces. As a component of the tandem force sensor, a cylindrical traction force sensor is developed to detect the traction force applied by hands. Its structure is designed to be suitable for humans to operate, and the mechanical model of its cylinder-shaped elastic structural body has been analyzed. After calibration, the cylindrical traction force sensor is proven to be able to detect forces/moments with small errors. Then, a tandem force sensor is developed based on the developed cylindrical traction force sensor and a wrist force sensor. The robot teaching experiment of drawer switches were made and the results confirm that the developed traction force sensor is simple to operate and the tandem force sensor can achieve the perception of the traction and contact forces.

A case study in human–robot collaboration in the disassembly of press-fitted components

2019 ◽  
Vol 234 (3) ◽  
pp. 654-664 ◽  
Author(s):  
Jun Huang ◽  
Duc Truong Pham ◽  
Yongjing Wang ◽  
Mo Qu ◽  
Chunqian Ji ◽  
...  
Keyword(s):  
End Of Life ◽  
Industrial Robot ◽  
New Method ◽  
Water Pump ◽  
Compliance Control ◽  
Critical Step ◽  
Active Compliance ◽  
Human Robot Collaboration ◽  
Collaborative Robot

Human–robot collaborative disassembly is an approach designed to mitigate the effects of uncertainties associated with the condition of end-of-life products returned for remanufacturing. This flexible semi-autonomous approach can also handle unpredictability in the frequency and numbers of such returns as well as variance in the remanufacturing process. This article focusses on disassembly, which is the first and arguably the most critical step in remanufacturing. The article presents a new method for disassembling press-fitted components using human–robot collaboration based on the active compliance provided by a collaborative robot. The article first introduces the concepts of human–robot collaborative disassembly and outlines the method of active compliance control. It then details a case study designed to demonstrate the proposed method. The study involved the disassembly of an automotive water pump by a collaborative industrial robot working with a human operator to take apart components that had been press-fitted together. The results show the feasibility of the proposed method.

Design and Analysis of a Multimodal Grasper Having Shape Conformity and Within-Hand Manipulation With Adjustable Contact Forces

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Nagamanikandan Govindan ◽  
Asokan Thondiyath
Keyword(s):  
Control Strategies ◽  
Low Cost ◽  
Active Surface ◽  
Force Sensor ◽  
Contact Forces ◽  
Geometrical Shape ◽  
Planning And Control ◽  
Control Scheme ◽  
And Control ◽  
Compact Mechanism

Abstract This paper presents the design, analysis, and testing of a novel multimodal grasper having the capabilities of shape conformation, within-hand manipulation, and a built-in compact mechanism to vary the forces at the contact surface. The proposed grasper has two important qualities: versatility and less complexity. The former refers to the ability to grasp a range of objects having different geometrical shape, size, and payload and perform in-hand manipulations such as rolling and sliding, and the latter refers to the uncomplicated design, and ease of planning and control strategies. Increasing the number of functions performed by the grasper to adapt to a variety of tasks in structured and unstructured environments without increasing the mechanical complexity is the main interest of this research. The proposed grasper consists of two hybrid jaws having a rigid inner structure encompassed by a flexible, active gripping surface. The flexibility of the active surface has been exploited to achieve shape conformation, and the same has been utilized with a compact mechanism, introduced in the jaws, to vary the contact forces while grasping and manipulating an object. Simple and scalable structure, compactness, low cost, and simple control scheme are the main features of the proposed design. Detailed kinematic and static analysis are presented to show the capability of the grasper to adjust and estimate the contact forces without using a force sensor. Experiments are conducted on the fabricated prototype to validate the different modes of operation and to evaluate the advantages of the proposed concept.

Automated Robotic Deburring of Parts Using Compliance Control

1991 ◽  
Vol 113 (1) ◽  
pp. 60-66 ◽  
Author(s):  
M. G. Her ◽  
H. Kazerooni
Keyword(s):  
Cutting Forces ◽  
Control Method ◽  
Metal Removal ◽  
Roller Bearing ◽  
Force Sensor ◽  
Normal Direction ◽  
Contact Forces ◽  
Normal Vector ◽  
Two Dimensional ◽  
Removal Process

This work presents a method for robotic deburring of two-dimensional planar parts with unknown geometry. Robotic deburring requires “compliancy” and “stiffness” in the robot in the directions tangent and normal to the part, respectively. Compliancy in the tangential direction allows robotic accommodation of tangential cutting forces, while stiffness in the normal direction impedes a robotic response to normal cutting forces. But, to track the part contour, the robot requires compliancy in the normal direction. These conflicting requirements are addressed in this article as two problems: control of the metal removal process and tracking of the part contour. In general, these two problems are coupled; however, here they are separated into a hardware problem and a control problem. A tracking mechanism has been designed and built which incorporates a roller bearing mounted on a force sensor at the robot endpoint. This force sensor is located directly below the cutter and measures the contact forces which are the input to the tracking controller. These contact forces are used not only to calculate the normal vector to the part surface, but also to generate compliancy in the robot. However, the deburring algorithm uses another set of forces (cutting forces generated by the cutter) to produce a stable metal removal process. This deburring control method guarantees compliancy and stiffness in the robot in response to the tangential and normal cutting forces, respectively. Experimental results are given to show the effectiveness of this method for deburring of two-dimensional parts with unknown geometry.

Vision-based calibration/compensation technique for automatic stiffener bonder

2016 ◽  
Vol 231 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Su Ye ◽  
Yutang Ye ◽  
Yu Xie ◽  
Ying Luo ◽  
Chunlei Du
Keyword(s):  
Error Compensation ◽  
Least Squares Method ◽  
Error Model ◽  
Compensation Method ◽  
Calibration Error ◽  
Model Parameters ◽  
Coordinate Systems ◽  
Printed Circuit ◽  
Pick And Place ◽  
Flexible Printed Circuit

This study developed a novel error compensation method aimed at eliminating placement error caused by hand–eye calibration and pick-and-place tool motions in automatic stiffener bonder for flexible printed circuit. Using the transformation of homogeneous coordinates to develop an error model of the system describing the coupling of errors among various coordinate systems, the least squares method is used to calculate the unknown model parameters. The experiment results demonstrate that this error compensation method reduced placement error by an order of magnitude. The mounting precision throughout the entire work area was ±0.046 mm at 3sigma, and for flexible printed circuit products with a specification limit of 0.1 mm, the process capability index of the automatic stiffener bonder in this study was 2.19. This represents that the system is capable of fully satisfying the precision requirements of flexible printed circuit stiffener bonding. The proposed system employing a vibrating feeder bowl and machine vision–aided target positioning is applicable to a variety of stiffeners, which enhances production flexibility. The proposed error model considers the complex coupling effect of the errors among multiple coordinate systems in hand–eye calibration, without the need of detecting and calculating the calibration error item by item, and takes into account the errors produced by the rotation and downward pressing motions of the pick-and-place tool.

Contact Forces in Unguided Vibratory Finishing

2015 ◽  
Author(s):  
Richard Brocker ◽  
Frederik Vits ◽  
Patrick Mattfeld ◽  
Fritz Klocke
Keyword(s):  
Measurement System ◽  
Removal Rate ◽  
Electrical Power ◽  
Force Sensor ◽  
Contact Forces ◽  
Work Piece ◽  
Data Logging ◽  
Vibratory Finishing ◽  
Revolution Speed ◽  
Finishing Processes

In vibratory finishing the material removal rate is influenced by the contact forces between work piece and media. In this paper a measurement system is presented which is capable of measuring the contact forces between work piece and media in unguided vibratory finishing. The unique feature of the measurement system is its completely wireless construction. The measurement results are not influenced by wires of the force sensor system including the electrical power supply and the data logging. By means of this measurement system, contact forces can be measured in unguided vibratory finishing processes for the first time. Furthermore, the influence of media size and adjustment of the unbalance motor like revolution speed, phase angle and mass distribution between the upper and the lower eccentric weight was investigated.

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