scholarly journals Effect of Robot Dynamics on the Machining Forces in Robotic Milling

2017 ◽  
Vol 10 ◽  
pp. 486-496 ◽  
Author(s):  
Lejun Cen ◽  
Shreyes N. Melkote
Keyword(s):  
Robot Dynamics ◽  
Machining Forces ◽  
Robotic Milling

scholarly journals A Novel Finite Element Method Approach in the Modelling of Edge Trimming of CFRP Laminates

2021 ◽  
Vol 11 (11) ◽  
pp. 4743
Author(s):  
Fernando Cepero-Mejias ◽  
Nicolas Duboust ◽  
Vaibhav A. Phadnis ◽  
Kevin Kerrigan ◽  
Jose L. Curiel-Sosa
Keyword(s):  
Finite Element ◽  
Tool Wear ◽  
Cutting Tool ◽  
Machining Process ◽  
Machining Forces ◽  
General Terms ◽  
Numerical Predictions ◽  
Composite Damage ◽  
Edge Trimming ◽  
Optimal Cutting Parameters

Nowadays, the development of robust finite element models is vital to research cost-effectively the optimal cutting parameters of a composite machining process. However, various factors, such as the high computational cost or the complicated nature of the interaction between the workpiece and the cutting tool significantly hinder the modelling of these types of processes. For these reasons, the numerical study of common machining operations, especially in composite machining, is still minimal. This paper presents a novel approach comprising a mixed multidirectional composite damage mode with composite edge trimming operation. An ingenious finite element framework which infer the cutting edge tool wear assessing the incremental change of the machining forces is developed. This information is essential to replace tool inserts before the tool wear could cause severe damage in the machined parts. Two unidirectional carbon fibre specimens with fibre orientations of 45∘ and 90∘ manufactured by pre-preg layup and cured in an autoclave were tested. Excellent machining force predictions were obtained with errors below 10% from the experimental trials. A consistent 2D FE composite damage model previously performed in composite machining was implemented to mimic the material failure during the machining process. The simulation of the spring back effect was shown to notably increase the accuracy of the numerical predictions in comparison to similar investigations. Global cutting forces simulated were analysed together with the cutting tool tooth forces to extract interesting conclusions regarding the forces received by the spindle axis and the cutting tool tooth, respectively. In general terms, vertical and normal forces steadily increase with tool wear, while tangential to the cutting tool, tooth and horizontal machining forces do not undergo a notable variation.

scholarly journals The Study of Dynamic Modeling and Multivariable Feedback Control for Flexible Manipulators with Friction Effect and Terminal Load

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1522
Author(s):  
Fuli Zhang ◽  
Zhaohui Yuan
Keyword(s):  
Dynamic Model ◽  
Vibration Suppression ◽  
Control Method ◽  
Coupling Effect ◽  
Flexible Manipulator ◽  
Flexible Beam ◽  
Robot Dynamics ◽  
Joint Friction ◽  
Balance Principle ◽  
Multivariable Feedback

The flexible manipulato is widely used in the aerospace industry and various other special fields. Control accuracy is affected by the flexibility, joint friction, and terminal load. Therefore, this paper establishes a robot dynamics model under the coupling effect of flexibility, friction, and terminal load, and analyzes and studies its control. First of all, taking the structure of the central rigid body, the flexible beam, and load as the research object, the dynamic model of a flexible manipulator with terminal load is established by using the hypothesis mode and the Lagrange method. Based on the balance principle of the force and moment, the friction under the influence of flexibility and load is recalculated, and the dynamic model of the manipulator is further improved. Secondly, the coupled dynamic system is decomposed and the controller is designed by the multivariable feedback controller. Finally, using MATLAB as the simulation platform, the feasibility of dynamic simulation is verified through simulation comparison. The results show that the vibration amplitude can be reduced with the increase of friction coefficient. As the load increases, the vibration can increase further. The trajectory tracking and vibration suppression of the manipulator are effective under the control method of multi-feedback moment calculation. The research is of great significance to the control of flexible robots under the influence of multiple factors.

A Survey on Brachiation Robots: An Energy-Based Review

Robotica ◽  
2021 ◽  
pp. 1-13
Author(s):  
Sibyla Andreuchetti ◽  
Vinícius M. Oliveira ◽  
Toshio Fukuda
Keyword(s):  
Special Class ◽  
Control Strategies ◽  
Underactuated Systems ◽  
Decision Variable ◽  
Robot Dynamics ◽  
Technical Literature ◽  
Control Schemes

SUMMARY Many different control schemes have been proposed in the technical literature to control the special class of underactuated systems, the- so-called brachiation robots. However, most of these schemes are limited with regard to the method by which the robot executes the brachiation movement. Moreover, many of these control strategies do not take into account the energy of the system as a decision variable. To observe the behavior of the system’s, energy is very important for a better understanding of the robot dynamics while performing the motion. This paper discusses a variety of energy-based strategies to better understand how the system’s energy may influence the type of motion (under-swing or overhand) the robot should perform.

scholarly journals Effects of hybrid Al2O3–CuO nanofluids on surface roughness and machining forces during turning AISI 4340

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Shahin Haghnazari ◽  
Vahid Abedini
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Rotational Speed ◽  
Minimum Quantity Lubrication ◽  
Weight Percent ◽  
Cutting Fluid ◽  
Hybrid Nanofluid ◽  
Workpiece Material ◽  
Machining Forces ◽  
Aisi 4340

AbstractThis paper presents an effort to model the process parameters involved in turning of alloy steel AISI 4340 workpiece material with Al2O3 and CuO hybrid nanofluids using the minimum quantity lubrication (MQL) method. In this paper, the effect of mixing two nanoparticles (Al2O3 and CuO) with different weight percent in environmentally friendly water-based cutting fluid, the rotational speed, and the feed rate has been investigated on the surface roughness and the machining forces using the response surface method. The results of the experiments show that the hybrid nanofluid containing 0.75 CuO with 0.25 Al2O3 has the best output for the machining forces and the surface roughness. Also, in the best composition of the nanoparticles (0.75 CuO with 0.25 Al2O3), the lowest value of machining forces has been achieved at a feed rate of 0.08 mm per revolution and the rotational speed 1000 rpm as well as the lowest value of the surface roughness at a feed rate of 0.08 mm per revolution and the rotational speed 710 rpm.

Parallel Processing of Robot Dynamics Simulation Using Optimal Multiprocessor Scheduling Algorithms

1988 ◽  
Vol 19 (10) ◽  
pp. 45-54
Author(s):  
Hironori Kasahara ◽  
Masahiko Iwata ◽  
Seinosuke Narita ◽  
Hirofumi Fujii
Keyword(s):  
Parallel Processing ◽  
Scheduling Algorithms ◽  
Multiprocessor Scheduling ◽  
Dynamics Simulation ◽  
Robot Dynamics

scholarly journals Multiobjective Trajectory Optimization and Adaptive Backstepping Control for Rubber Unstacking Robot Based on RFWNN Method

2018 ◽  
Vol 2018 ◽  
pp. 1-19
Author(s):  
Le Liang ◽  
Yanjie Liu ◽  
Hao Xu
Keyword(s):  
Trajectory Optimization ◽  
Control Method ◽  
External Disturbance ◽  
Backstepping Control ◽  
Adaptive Robust Control ◽  
Robot Dynamics ◽  
Adaptive Backstepping ◽  
Recycling Process ◽  
Adaptive Backstepping Control ◽  
Modeling Uncertainties

Multiobjective trajectory optimization and adaptive backstepping control method based on recursive fuzzy wavelet neural network (RFWNN) are proposed to solve the problem of dynamic modeling uncertainties and strong external disturbance of the rubber unstacking robot during recycling process. First, according to the rubber viscoelastic properties, the Hunt-Crossley nonlinear model is used to construct the robot dynamics model. Then, combined with the dynamic model and the recycling process characteristics, the multiobjective trajectory optimization of the rubber unstacking robot is carried out for the operational efficiency, the running trajectory smoothness, and the energy consumption. Based on the trajectory optimization results, the adaptive backstepping control method based on RFWNN is adopted. The RFWNN method is applied in the main controller to cope with time-varying uncertainties of the robot dynamic system. Simultaneously, an adaptive robust control law is developed to eliminate inevitable approximation errors and unknown disturbances and relax the requirement for prior knowledge of the controlled system. Finally, the validity of the proposed control strategy is verified by experiment.

Ermitteln von Lagefehlern bei Einlippenbohrern/Determination of position errors in single-lip drills

2021 ◽  
Vol 111 (05) ◽  
pp. 355-361
Author(s):  
Maximilian Schweigart ◽  
Hans-Christian Möhring
Keyword(s):  
Measuring Method ◽  
Polar Coordinates ◽  
Machining Forces ◽  
Actual Position ◽  
Position Errors ◽  
Machine Spindle ◽  
Laser Profile

Dieser Beitrag stellt eine berührungslose Messmethode zur Feststellung von Lagefehlern bei Einlippenbohrern vor, die auf der Verwendung eines Laser-Profilsensors basiert. Durch die Messung von Verlagerungen an mehreren Positionen entlang des langsam rotierenden Werkzeugschafts kann die Lage des Werkzeugs in Polarkoordinaten abgebildet werden. Das System bietet die Möglichkeit sowohl herstellungsbedingte Fehler als auch durch Bearbeitungskräfte und -momente verursachte Formänderungen des Werkzeugs nach verschiedenen Schnittwegen feststellen zu können.   This article introduces a non-contact measuring method, based on the use of a laser profile sensor to determine position errors in single-lip drills. By measuring displacements at several positions along the tool shaft with the machine spindle rotating slowly, the actual position of the tool can be mapped in polar coordinates. The system thus offers the potential to identify manufacturing-related errors as well as changes in the shape of the tool caused by machining forces and torques after different cutting paths.

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