Parametric Multibody Modeling of Anthropomorphic Robot to Predict Joint Compliance Influence on End Effector Positioning

2013 ◽  
Author(s):  
Stefano Baglioni ◽  
Filippo Cianetti ◽  
Claudio Braccesi ◽  
Luca Landi
Keyword(s):  
Operating Conditions ◽  
Industrial Robots ◽  
Numerical Code ◽  
Transmission Ratio ◽  
Harmonic Drive ◽  
Simulation Approach ◽  
End Effector ◽  
Joint Compliance ◽  
High Transmission ◽  
Modelling Procedure

Nowadays, in the field of robotic, one of the most important objectives is to reduce robot error positioning and improve its dynamic behaviour. One of the main source of error in end effector positioning is due to the joint compliance: robot joint components under operating conditions can be deformed as a function of their stiffness/damping properties. Generally, for industrial robots, harmonic drive gearings are used, their principal characteristics are high transmission ratio and law weight, on the other hand, to realize high transmission ratio, harmonic drive gearings work on inner gear elastic deformation, conferring to the robot joints an excessive compliance that, in some robot applications, cannot be neglected. In this research activity multibody modelling and simulation approach has been used to analyse joint compliance influence on robot position accuracy. The principal aim of this work was the formulation of a modelling procedure that starting from classical robots modelling approach (i.e. Denavit Hartenberg) defines an universal database and a parametric modelling procedure that allows the designer to use any multibody commercial codes to analyse anthropomorphic robots considering or not the compliance effect. All the procedure was developed and managed into a numerical code environment (Matlab/Simulink). An example of commercial anthropomorphic robot was considered by assuming its principal kinematic and dynamic characteristics. Parametric models of the robot have been developed in two different multibody modelling environments (Simmechanics, Adams/View). Moreover the models structure has been built in order to control the robot movements both in motion (open loop) or in force (closed loop). In this case they are interfaced with Simulink code in a so called co-simulation approach that allows to developed a generic control system and test it by using one or more models, less or more refined.

Finding Features of Positioning Error for Large Industrial Robots Based on Convolutional Neural Network

2021 ◽  
Author(s):  
Daiki Kato ◽  
Kenya Yoshitugu ◽  
Naoki Maeda ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Production Systems ◽  
Industrial Robot ◽  
Three Dimensional ◽  
Industrial Robots ◽  
Numerical Control ◽  
Robot Motion ◽  
Positioning Error ◽  
End Effector

Abstract Most industrial robots are taught using the teaching playback method; therefore, they are unsuitable for use in variable production systems. Although offline teaching methods have been developed, they have not been practiced because of the low accuracy of the position and posture of the end-effector. Therefore, many studies have attempted to calibrate the position and posture but have not reached a practical level, as such methods consider the joint angle when the robot is stationary rather than the features during robot motion. Currently, it is easy to obtain servo information under numerical control operations owing to the Internet of Things technologies. In this study, we propose a method for obtaining servo information during robot motion and converting it into images to find features using a convolutional neural network (CNN). Herein, a large industrial robot was used. The three-dimensional coordinates of the end-effector were obtained using a laser tracker. The positioning error of the robot was accurately learned by the CNN. We extracted the features of the points where the positioning error was extremely large. By extracting the features of the X-axis positioning error using the CNN, the joint 1 current is a feature. This indicates that the vibration current in joint 1 is a factor in the X-axis positioning error.

Development of an End-Effector for Mitigation of Collisions

2021 ◽  
Author(s):  
Domenico Tommasino ◽  
Matteo Bottin ◽  
Giulio Cipriani ◽  
Alberto Doria ◽  
Giulio Rosati
Keyword(s):  
Numerical Simulations ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Contact Forces ◽  
Design Parameters ◽  
End Effector ◽  
Linear Behavior ◽  
Stable Mechanism ◽  
Robot Tasks ◽  
The Impact

Abstract In robotics the risk of collisions is present both in industrial applications and in remote handling. If a collision occurs, the impact may damage both the robot and external equipment, which may result in successive imprecise robot tasks or line stops, reducing robot efficiency. As a result, appropriate collision avoidance algorithms should be used or, if it is not possible, the robot must be able to react to impacts reducing the contact forces. For this purpose, this paper focuses on the development of a special end-effector that can withstand impacts and is able to protect the robot from impulsive forces. The novel end-effector is based on a bi-stable mechanism that decouples the dynamics of the end-effector from the dynamics of the robot. The intrinsically non-linear behavior of the end-effector is investigated with the aid of numerical simulations. The effect of design parameters and the operating conditions are analyzed and the interaction between the functioning of the bi-stable mechanism and the control system is studied. In particular, the effect of the mechanism in different scenarios characterized by different robot velocities is shown. Results of numerical simulations assess the validity of the proposed end-effector, which can lead to large reductions in impact forces.

scholarly journals Automated Analysis of Meshing Performance of Harmonic Drive Gears Under Various Operating Conditions

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 68137-68154 ◽  
Author(s):  
Donghui Ma ◽  
Rui Wang ◽  
Pengfei Rao ◽  
Ruomin Sui ◽  
Shaoze Yan
Keyword(s):  
Automated Analysis ◽  
Operating Conditions ◽  
Harmonic Drive

scholarly journals Detachable Robotic Grippers for Human-Robot Collaboration

2021 ◽  
Vol 8 ◽  
Author(s):  
Zubair Iqbal ◽  
Maria Pozzi ◽  
Domenico Prattichizzo ◽  
Gionata Salvietti
Keyword(s):  
Degrees Of Freedom ◽  
Tactile Feedback ◽  
Industrial Robots ◽  
Physical Interaction ◽  
Robot Arm ◽  
Robotic Hands ◽  
End Effector ◽  
External Power ◽  
Self Powered ◽  
Automatic Tool

Collaborative robots promise to add flexibility to production cells thanks to the fact that they can work not only close to humans but also with humans. The possibility of a direct physical interaction between humans and robots allows to perform operations that were inconceivable with industrial robots. Collaborative soft grippers have been recently introduced to extend this possibility beyond the robot end-effector, making humans able to directly act on robotic hands. In this work, we propose to exploit collaborative grippers in a novel paradigm in which these devices can be easily attached and detached from the robot arm and used also independently from it. This is possible only with self-powered hands, that are still quite uncommon in the market. In the presented paradigm not only hands can be attached/detached to/from the robot end-effector as if they were simple tools, but they can also remain active and fully functional after detachment. This ensures all the advantages brought in by tool changers, that allow for quick and possibly automatic tool exchange at the robot end-effector, but also gives the possibility of using the hand capabilities and degrees of freedom without the need of an arm or of external power supplies. In this paper, the concept of detachable robotic grippers is introduced and demonstrated through two illustrative tasks conducted with a new tool changer designed for collaborative grippers. The novel tool changer embeds electromagnets that are used to add safety during attach/detach operations. The activation of the electromagnets is controlled through a wearable interface capable of providing tactile feedback. The usability of the system is confirmed by the evaluations of 12 users.

Robot end effector based on electrostatic adsorption for manipulating garment fabrics

2021 ◽  
pp. 004051752110418
Author(s):  
Wenqian Feng ◽  
Yanli Hu ◽  
Xin rong Li ◽  
Lidong Liu
Keyword(s):  
Adsorption Capacity ◽  
Structural Parameters ◽  
Garment Industry ◽  
Industrial Robots ◽  
Force Model ◽  
Adsorption Effect ◽  
Electrostatic Adsorption ◽  
End Effector ◽  
Application Range ◽  
Capacity Model

To improve the effectiveness of industrial robots in the textile and garment industry, it is necessary to expand the application range of electrostatic adsorption end effectors and solve the problem of automatically grasping and transferring fabrics during garment processing. Taking weft-knit fabric as an example, this paper begins by analyzing the factors that influence the electrostatic adsorption capacity, and then constructing an electrostatic adsorption capacity model based on the fabric characteristics. Next, the shape arrangement and structural parameters of the electrode plate are optimized by taking the electrostatic adsorption force model and maximizing the adsorption force per unit area. Finally, the adsorption effect of the electrostatic adsorption end effector is verified by simulation and experiment. The verification results show that the electrode with a comb-shaped arrangement and optimized structural parameters can adsorb clothing fabric well and meets the requirements of clothing automated production lines. This study provides a new method for solving the problem of automatically grasping and transferring fabrics and provides technical support for improving automation in the garment industry.

Neural network modeling of hysteresis for harmonic drive in industrial robots

2019 ◽  
Vol 27 (3) ◽  
pp. 694-701
Author(s):  
党选举 DANG Xuan-ju ◽  
王凯利 WANG Kai-li ◽  
姜 辉 JIANG Hui ◽  
伍锡如 WU Xi-ru ◽  
张向文 ZHANG Xiang-wen
Keyword(s):  
Neural Network ◽  
Network Modeling ◽  
Industrial Robots ◽  
Neural Network Modeling ◽  
Harmonic Drive

scholarly journals Rotation-joint stiffness modeling for industrial robots considering contacts

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401879306 ◽  
Author(s):  
Zhifeng Liu ◽  
Jingjing Xu ◽  
Qiang Cheng ◽  
Yongsheng Zhao ◽  
Yanhu Pei
Keyword(s):  
Fractal Theory ◽  
Joint Stiffness ◽  
Industrial Robots ◽  
Torsional Stiffness ◽  
Equivalent Stiffness ◽  
Force Analysis ◽  
Joint System ◽  
End Effector ◽  
Stiffness Modeling ◽  
High Speeds

Joint flexibility has a major impact on the motion accuracy of a robotic end effector, particularly at high speeds. This work proposes a technique of precisely modeling the torsional stiffness of the rotational joints for the industrial robots. This technique considers the contacts that exist in the joint system, which can have a significant effect on the overall joint stiffness. The torsional stiffness of the connections that commonly exist in the rotational joints, such as the belt connection, the connections using key, bolts, and pins, were modeled by combining the force analysis and the fractal theory. Through modeling the equivalent stiffness for the springs in serial and in parallel, the torsional stiffness of all joints for the ER3A-C60 robot were calculated and analyzed. The results show that the estimated stiffness based on the proposed technique is closer to the actual values than that based on the previous model without considering the contacts. The analysis is useful for controlling the dynamic characteristic of the industrial robots with the rotational joints while planning the trajectory for the end effector.

scholarly journals Modular fastening system and tool–holder working unit for incremental forming

2019 ◽  
Vol 299 ◽  
pp. 05005
Author(s):  
Melania Tera ◽  
Claudia–Emilia Gîrjob ◽  
Cristina–Maria Biriș ◽  
Mihai Crenganiș
Keyword(s):  
Machine Tools ◽  
Incremental Forming ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Cnc Milling ◽  
End Effector ◽  
Tool Holder ◽  
Cnc Milling Machine ◽  
Milling Machines ◽  
Sheet Metal Workpiece

Incremental forming can be usually unfolded either on CNC milling machine–tools or serial industrial robots. The approach proposed in this paper tackles the problem of designing a modular fastening system, which can be adapted for both above mentioned technological equipment. The fastening system of the sheet–metal workpiece is composed of a fixing plate and a retaining plate. The fixing and retaining plates will be made up of different individual elements, which can be easily repositioned to obtain different sizes of the part. Moreover, the fastening system has to be able to be positioned either horizontally (to be fitted on CNC milling machines) or vertically (to be fitted on industrial robots. The paper also presents the design of a tool–holder working unit which will be fitted on KUKA KR 210 industrial robot. The working unit will be mounted as end–effector of the robot and will bear the punch, driving it on the processing toolpaths.

scholarly journals Online pose correction of an industrial robot using an optical coordinate measure machine system

2018 ◽  
Vol 15 (4) ◽  
pp. 172988141878791 ◽  
Author(s):  
Sepehr Gharaaty ◽  
Tingting Shu ◽  
Ahmed Joubair ◽  
Wen Fang Xie ◽  
Ilian A Bonev
Keyword(s):  
Root Mean Square ◽  
Spot Welding ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Mean Square ◽  
End Effector ◽  
Proportional Integral ◽  
Accuracy Requirement ◽  
Robot Controller ◽  
Correction Scheme

In this article, a dynamic pose correction scheme is proposed to enhance the pose accuracy of industrial robots. The dynamic pose correction scheme uses the dynamic pose measurements as feedback to accurately guide the robot end-effector to the desired pose. The pose is measured online with an optical coordinate measure machine, that is, C-Track 780 from Creaform. A root mean square method is proposed to filter the noise from the pose measurements. The dynamic pose correction scheme adopts proportional-integral-derivaitve controller and generates commands to the FANUC robot controller. The developed dynamic pose correction scheme has been tested on two industrial robots, FANUC LR Mate 200iC and FANUC M20iA. The experimental results on both robots demonstrate that the robots can reach the desired pose with an accuracy of ±0.050 mm for position and ±0.050° for orientation. As a result, the developed pose correction can make the industrial robots meet higher accuracy requirement in the applications such as riveting, drilling, and spot welding.

Steady State Performance Simulation of Natural Gas Pipeline Driven by Compressor Stations

2016 ◽  
Author(s):  
S. M. Suleiman ◽  
Y. G. Li
Keyword(s):  
Steady State ◽  
Natural Gas ◽  
Flow Rate ◽  
Operating Conditions ◽  
Simulation Approach ◽  
Gas Pipelines ◽  
Performance Simulation ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
Pumping Stations

Natural gas pipeline plays an important role in transporting natural gas over a long distance. Its performance and operating behavior are affected by many factors, such as ambient conditions, natural gas flow rate, operation and control of compressor pumping stations, etc. Better understanding of the performance and behavior of an integrated pipeline-compressor system used for gas transmission will be beneficial to both design and operation of natural gas pipelines. This paper introduces a novel steady-state thermodynamic performance simulation approach for natural gas pipelines based on fundamental thermodynamics with the inclusion of the coupling between a pipeline and compressor pumping stations. A pipeline resistance model, a compressor performance model characterized by an empirical compressor map and a pipeline control schedule for the operation of an integrated pipeline-compressor system are included in the simulation approach. The novel approach presented in this paper allows the analysis of the thermodynamic coupling between compressors and pipes and the off-design performance analysis of the integrated pipeline-compressor system. The introduced simulation approach has been applied to the performance simulation of a typical model pipeline driven by multiple centrifugal compressor pumping stations. It is assumed in the pipeline control schedule that the total pressure at the inlet of compressor stations is kept constant when pipeline operating condition changes. Such pipeline operating conditions include varying ambient temperature and varying natural gas volumetric flow rate. The performance behavior of the pipeline corresponding to the change of operating conditions has been successfully simulated. The introduced pipeline performance simulation approach is generic and can be applied to different pipeline-compressor systems.

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