Low Frequency Vibration Consideration in Tool-Path Computation of Two-Link Serial Manipulator for Improved Accuracy

2014 ◽  
Author(s):  
Denis Juschanin ◽  
Fisseha M. Alemayehu ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Mode Coupling ◽  
Tool Path ◽  
Industrial Robot ◽  
Research Question ◽  
Low Frequency ◽  
Industrial Robots ◽  
Machining Process ◽  
Future Research ◽  
Low Frequency Vibration ◽  
Path Computation

Industrial robots are flexible and cost-efficient tools for a multitude of applications such as, polishing, grinding, deburring, and welding. However, their utilization in machining tasks is currently limited due to insufficient position accuracy. This study aims to answer the research question: ‘Does including low frequency vibrations (mode coupling chatter) in tool path computation improve accuracy?’ For this purpose, the current paper focuses on setting-up a robust and flexible simulation framework. The framework implements a predictive cutting force method into a multibody dynamic (MBD) model of an industrial robot. The framework is structured in an extendable fashion for future research tasks. Future work will include mode coupling chatter into the MBD model to help mitigate the effects of chatter in robotic machining process, which in turn will increase tool-path accuracy.

Study on Improving Accuracy in Robotic Milling of Aluminum Alloy

2018 ◽  
Author(s):  
Shaochun Sui ◽  
Kai Guo ◽  
Jie Sun ◽  
Yiran Zang
Keyword(s):  
Aluminum Alloy ◽  
Industrial Robot ◽  
Vibration Signal ◽  
Industrial Robots ◽  
Machining Process ◽  
Cnc Machine ◽  
Machined Surface ◽  
Improving Accuracy ◽  
High Level ◽  
Monolithic Components

Nowadays, the application of using industrial robots in manufacture is a diminutive due to its own low rigidity and low stiffness. This leads to high level of vibrations that limits the quality and the precision of the workpiece. So they are usually used for welding, grinding and paint shop. However, the potential of industrial robot applications in machining has be realized. The volume of monolithic components is large and there are many issues in machining process such as geometric tolerance and quality of machined surface. In such cases the traditional CNC machine is replaced by industrial robots, which will reduce the production cost, reduce labor and increase the efficiency. In this paper, the milling experiment of 7050-T7451 aeronautical aluminum alloy was carried out by using industrial robot KR210 R2700. In addition, the experiment was employed to study the influence of milling speed, feed-rate, cutting depth and cutting width on vibrations, surface roughness was also measured to evaluate the machining quality. Besides, the axis of angle was changed which led to the different industrial robot’s postures. The vibration signal of different postures was acquired, which was used to analysis the optimal workspace of industrial robot. The best process parameters were obtained, which will play a guiding significance on the actual production.

New Approaches in Tool Path Optimization of CNC Machining: A Review

2014 ◽  
Vol 663 ◽  
pp. 657-661 ◽  
Author(s):  
Khashayar Danesh Narooei ◽  
Rizauddin Ramli
Keyword(s):  
Tool Path ◽  
Research Direction ◽  
Cnc Machining ◽  
Numerical Control ◽  
Path Optimization ◽  
Machining Process ◽  
Future Research ◽  
Automotive Manufacturing ◽  
Tool Path Optimization ◽  
Automotive Part

Computer numerical control (CNC) machines have been widely used in automotive manufacturing industries especially of machining operation in automotive part such as engine body and cylinder. One of the key features that improve efficiency of CNC machining is through the optimization of tool path. Previous researcher to optimize tool path has premeditated several approaches. This paper aims to provide a critical review of those approaches that have been developed in tool path. The developed tool path approaches covered different types of machining process under various constraints condition. This paper focuses on tool path generation in CNC machining such as milling and cutting process. Based on our finding, this review paper collects information on tool path optimization and recommends future research direction.

Recent Advances in Quasi-Zero-Stiffness Vibration Isolation Systems

2013 ◽  
Vol 397-400 ◽  
pp. 295-303 ◽  
Author(s):  
Fu Niu ◽  
Ling Shuai Meng ◽  
Wen Juan Wu ◽  
Jing Gong Sun ◽  
Wei Hua Su ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Future Research ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Significant Development ◽  
Recent Advances ◽  
Low Frequency Vibration ◽  
Future Research Directions ◽  
Isolation Systems

The quasi-zero-stiffness vibration isolation system has witnessed significant development due to the pressing demands for low frequency and ultra-low frequency vibration isolation. In this study, the isolation theory and the characteristic of the quasi-zero-stiffness vibration isolation system are illustrated. Based on its implementation mechanics, a comprehensive assessment of recent advances of the quasi-zero-stiffness vibration isolation system is presented. The future research directions are finally prospected.

Sea Motion Simulation, Very Low Frequency Vibration, and Motion Sickness

1976 ◽  
Vol 20 (20) ◽  
pp. 462-462
Author(s):  
Michael E. McCauley
Keyword(s):  
Motion Sickness ◽  
Degrees Of Freedom ◽  
Low Frequency ◽  
Vertical Motion ◽  
Basic Research ◽  
Future Research ◽  
Naval Research ◽  
Low Frequency Vibration ◽  
Office Of Naval Research ◽  
Linear Oscillation

The office of Naval Research/Human Factors Research (ONR/HFR) Motion Generator was designed with three degrees of freedom (heave, pitch, and roll) to simulate the motion of an air-sea craft in varying ocean conditions through Sea State 5. Recent upgrading of the device has provided the capability for simulating the motion of advanced design sea craft as well as certain aspects of vertical motion common to land, sea, and air vehicles. Since 1968, the simulator has been used for investigation of the following topics: (1) basic research to provide equations for the prediction of motion sickness incidence based on parameters of vertical linear oscillation, (2) crew performance during simulated motion of two types of proposed naval vessels, and (3) evaluation of the efficacy of antimotion sickness medications in alleviating the symptoms of motion sickness. This simulator provides the opportunity for future research on the effects of motion on physiological and psychological processes as well as task performance.

scholarly journals Development and Investigation of an Inexpensive Low Frequency Vibration Platform for Enhancing the Performance of Electrical Discharge Machining Process

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6192
Author(s):  
Abhimanyu Singh Mertiya ◽  
Aman Upadhyay ◽  
Kaustubh Nirwan ◽  
Pravin Pandit Harane ◽  
Ahmad Majdi Abdul-Rani ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Low Frequency ◽  
Machining Process ◽  
Machining Parameters ◽  
Peak Current ◽  
Low Frequency Vibration ◽  
Debris Removal ◽  
Vibration Assistance ◽  
Discharge Gap

Difficulty in debris removal and the transport of fresh dielectric into discharge gap hinders the process performance of electrical discharge machining (EDM) process. Therefore, in this work, an economical low frequency vibration platform was developed to improve the performance of EDM through vibration assistance. The developed vibratory platform functions on an eccentric weight principle and generates a low frequency vibration in the range of 0–100 Hz. The performance of EDM was evaluated in terms of the average surface roughness (Ra), material removal rate (MRR), and tool wear rate (TWR) whilst varying the input machining parameters viz. the pulse-on-time (Ton), peak current (Ip), vibration frequency (VF), and tool rotational speed (TRS). The peak current was found to be the most significant parameter and contributed by 78.16%, 65.86%, and 59.52% to the Ra, MRR, and TWR, respectively. The low frequency work piece vibration contributed to an enhanced surface finish owing to an improved flushing at the discharge gap and debris removal. However, VF range below 100 Hz was not found to be suitable for the satisfactory improvement of the MRR and reduction of the TWR in an electrical discharge drilling operation at selected machining conditions.

scholarly journals A Brief Review of Robotic Machining

2019 ◽  
Vol 71 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Alexandru Bârsan
Keyword(s):  
Cost Saving ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Future Research ◽  
Manufacturing Processes ◽  
Robotic Machining ◽  
Subtractive Manufacturing ◽  
Complex Automation

Abstract The approach of this paper was to analyze the technical borders of industrial robots and to provide an overview of current technology, technical constraints and the potential types of future research suggestion concerning robotic machining. These complex automation machines used in manufacturing processes are an emerging chapter of industrial engineering that contribute to automatically performing operation in subtractive manufacturing and sheet metal forming processes. Compared with CNC machines which have shape limitations and have the restricted working area, the industrial robot is a flexible, cost-saving alternative.

scholarly journals Linear System Identification and Vibration Control of End-Effector for Industrial Robots

2020 ◽  
Vol 10 (23) ◽  
pp. 8537
Author(s):  
Xiaobiao Shan ◽  
Henan Song ◽  
Chong Zhang ◽  
Guangyan Wang ◽  
Jizhuang Fan
Keyword(s):  
State Space ◽  
Vibration Suppression ◽  
State Space Model ◽  
Low Frequency ◽  
Industrial Robots ◽  
Linear Quadratic ◽  
Discrete State ◽  
End Effector ◽  
Low Frequency Vibration ◽  
Estimation Signal

This paper presents the discrete state space mathematical model of the end-effector in industrial robots and designs the linear-quadratic-Gaussian controller, called LQG controller for short, to solve the low frequency vibration problem. Though simplifying the end-effector as the cantilever beam, this paper uses the subspace identification method to determine the output dynamic response data and establishes the state space model. Experimentally comparing the influences of different input excitation signals, Chirp sequences from 0 Hz to 100 Hz are used as the final estimation signal and the excitation signal. The LQG controller is designed and simulated to achieve the low frequency vibration suppression of the structure. The results show that the suppression system can effectively suppress the fundamental natural frequency and lower vibration of end-effector. The vibration suppression percentage is 95%, and the vibration amplitude is successfully reduced from ±20 μm to ±1 μm. The present work provides an effective method to suppress the low frequency vibration of the end-effector for industrial robots.

A comparative evaluation of three industrial robots using three reference measuring techniques

2015 ◽  
Vol 42 (6) ◽  
pp. 572-585 ◽  
Author(s):  
Mohamed Slamani ◽  
Ahmed Joubair ◽  
Ilian A. Bonev
Keyword(s):  
Manufacturing Systems ◽  
Tool Path ◽  
Laser Interferometer ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Laser Tracker ◽  
Specific Test ◽  
Reference Measuring ◽  
Content Type ◽  
Robot Selection

Purpose – The purpose of this paper is to present a technique for assessing and comparing the static and dynamic performance of three different models of small six-axis industrial robots using a Renishaw XL80 laser interferometer system, a FARO ION laser tracker and a Renishaw QC20-W telescoping ballbar. Design/methodology/approach – Specific test methods are proposed in this work, and each robot has been measured in a similar area of its working envelope. The laser interferometer measurement instrument is used to assess the static positioning performance along three linear and orthogonal paths. The laser tracker is used to assess the contouring performance at different tool center point (TCP) speeds along a triangular tool path, whereas the telescoping ballbar is used to assess the dynamic positioning performance for circular paths at different TCP speeds and trajectory radii. Findings – It is found that the tested robots behave differently, and that the static accuracy of these non-calibrated robots varies between 0.5 and 2.3 mm. On the other hand, results show that these three robots can provide acceptable corner tracking at low TCP speeds. However, a significant overshoot at the corner is observed at high TCP speed for all the robots tested. It was also found that the smallest increment of Cartesian displacement (Cartesian resolution) that can be taken by the tested robots is approximately 50 μm. Practical implications – The technique used in this paper allows extremely accurate diagnosis of the robot performance, which makes it possible for the robot user to determine whether the robot is in good or bad condition. It can also help the decision-maker to select the most suitable industrial robot to achieve the desired task with minimum cost and specific application ability. Originality/value – This paper proposed a new method based on the performance verification approach for solving the robot selection problem for flexible manufacturing systems. Furthermore, despite their importance, bidirectional repeatability and Cartesian resolution are never specified by the manufacturers of industrial robots nor are they described in the ISO 9283:1998 guide, and they are rarely the object of performance assessments. In this work, specific tests are performed to check and quantify the bidirectional repeatability and the Cartesian resolution of each robot.

Performance Criteria to Evaluate a Kinematically Redundant Robotic Cell for Machining Tasks

2012 ◽  
Vol 162 ◽  
pp. 413-422 ◽  
Author(s):  
Kévin Subrin ◽  
Laurent Sabourin ◽  
Grigore Gogu ◽  
Youcef Mezouar
Keyword(s):  
High Speed ◽  
Dynamic Capabilities ◽  
Industrial Robot ◽  
Kinematic Model ◽  
Geometrical Model ◽  
Industrial Robots ◽  
Machining Process ◽  
Performance Criteria ◽  
Robotic Cell ◽  
Speed Accuracy

Machine tools and robots have both evolved fundamentally and we can now question the abilities of new industrial robots concerning accurate task realization under high constraints. Requirements in terms of kinematic and dynamic capabilities in High Speed Machining (HSM) are increasingly demanding. To face the challenge of performance improvement, parallel and hybrid robotic architectures have emerged and a new generation of industrial serial robots with the ability to perform machining tasks has been designed. In this paper, we propose to evaluate the performance criteria of an industrial robot included in a kinematically redundant robotic cell dedicated to a machining task. Firstly, we present the constraints of the machining process (speed, accuracy etc.). We then detail the direct geometrical model and the kinematic model of a robot with closed chain in the arm and we propose a procedure for managing kinematic redundancy whilst integrating various criteria. Finally, we present the evolution of the criteria for a given trajectory in order to define the best location for a rotary table and to analyze the manipulators stiffness.

Effects of tool intermittent vibration on helical internal hole processing in electrochemical machining

2018 ◽  
Vol 233 (12) ◽  
pp. 4102-4111 ◽  
Author(s):  
Minghuan Wang ◽  
Yaobin Zhang ◽  
Xufeng Xu ◽  
Guoda Chen ◽  
Adam T Clare ◽  
...  
Keyword(s):  
Vibration Amplitude ◽  
Flow Direction ◽  
Fluid Velocity ◽  
Electrochemical Machining ◽  
Low Frequency ◽  
Experimental Tests ◽  
Groove Depth ◽  
Machining Process ◽  
Low Frequency Vibration ◽  
Interelectrode Gap

Ribbed holes can serve to increase the efficiency of the heat exchangers and improve the performance of industrial equipment. Increasing demand for small ribbed holes is a key driver in manufacturing technology research. Electrochemical machining has been shown to be a promising method for this. In this paper, an intermittent low-frequency vibration tool is used to demonstrate significant improvement to the geometry of internal ribbed holes. The process stability, material removal rates, and uniformity of features along the flow direction are improved. Firstly, a 3D model of the flow field within the interelectrode gap was developed to calculate and governing flow regime in the interelectrode gap. The simulation demonstrated that the fluid velocity fluctuates periodically and this enhances electrolyte flushing in the interelectrode gap during the machining process. Then, experimental tests for the manufacture of spiral ribs on small holes (Ø1.5 mm and 20–40 mm depth) are also demonstrated with accompanying variation of the tool vibration amplitude and frequency, respectively. Results show that groove depth was most greatly influenced by the vibration amplitude and that better uniformity could be obtained at higher vibration frequencies. The groove depth increased by 15% over nonvibrating control tests with enhanced uniformity.

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