Development and Implementation of Orthogonal Planes Images Method for Calibration of Tool Centre Point

2016 ◽  
pp. 105-115 ◽  
Author(s):  
Zaviša Gordić ◽  
Claudio Ongaro
Keyword(s):  
Tool Centre Point

EFFECT OF SERVO SYSTEMS ON THE CONTOURING ERRORS IN INDUSTRIAL ROBOTS

2012 ◽  
Vol 36 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Mohamed Slamani ◽  
Albert Nubiola ◽  
Ilian A. Bonev
Keyword(s):  
High Speed ◽  
Industrial Robot ◽  
Statistical Tests ◽  
Measurement Instrument ◽  
Servo System ◽  
Industrial Robots ◽  
Structural Vibration ◽  
Tool Centre Point ◽  
Prediction Capability ◽  
Radius Size

Two important aspects of the performance of a servo system, tracking errors and contour errors, significantly affect the accuracy of industrial robots under high-speed motion. Careful tuning of the control parameters in a servo system is essential, if the risk of severe structural vibration and a large contouring error is to be avoided. In this paper, we present an overview of a method to diagnose contouring errors caused by the servo control system of an ABB IRB 1600 industrial robot by measuring the robot’s motion accuracy in a Cartesian circular shape using a double ballbar (DBB) measurement instrument. Tests were carried out at different TCP (tool centre-point) speed and trajectory radii to investigate the main sources of errors that affect circular contouring accuracy. Results show that radius size errors and out-of-roundness are significant. A simple experimental model based on statistical tests was also developed to represent and predict the radius size error. The model was evaluated by comparing its prediction capability in several experiments. An excellent error prediction capability was observed.

Walk-through programming for robotic manipulators based on admittance control

Robotica ◽  
2013 ◽  
Vol 31 (7) ◽  
pp. 1143-1153 ◽  
Author(s):  
Luca Bascetta ◽  
Gianni Ferretti ◽  
Gianantonio Magnani ◽  
Paolo Rocco
Keyword(s):  
Robot Control ◽  
Industrial Robot ◽  
Robotic Manipulators ◽  
Programming System ◽  
Admittance Control ◽  
Safety Issues ◽  
Safety Strategies ◽  
Programming Techniques ◽  
Tool Centre Point ◽  
Safety Limit

SUMMARYThe present paper addresses the issues that should be covered in order to develop walk-through programming techniques (i.e. a manual guidance of the robot) in an industrial scenario. First, an exact formulation of the dynamics of the tool the human should feel when interacting with the robot is presented. Then, the paper discusses a way to implement such dynamics on an industrial robot equipped with an open robot control system and a wrist force/torque sensor, as well as the safety issues related to the walk-through programming. In particular, two strategies that make use of admittance control to constrain the robot motion are presented. One slows down the robot when the velocity of the tool centre point exceeds a specified safety limit, the other one limits the robot workspace by way of virtual safety surfaces. Experimental results on a COMAU Smart Six robot are presented, showing the performance of the walk-through programming system endowed with the two proposed safety strategies.

scholarly journals Cartesian space robot manipulator clamping movement in ROS simulation and experiment

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Longtao Mu ◽  
Yunfei Zhou ◽  
Tiebiao Zhao
Keyword(s):  
Motion Planning ◽  
Position Control ◽  
Robot Manipulator ◽  
Robotic Arm ◽  
Robot Motion ◽  
Robot Arm ◽  
Operation System ◽  
Model File ◽  
Simulation And Experiment ◽  
Tool Centre Point

Abstract This paper studies the robot arm sorting position control based on robot operation system (ROS), which works depending on the characteristics of the robot arm sorting operation using the top method, to automate the sorting operation and improve the work efficiency of workpiece sorting. Through the ROS MoveIt! module, the sorting pose and movement path of the robotic arm are planned, the inverse kinematics of the sorting robotic arm is solved, and the movement pose characteristics of the sorting robotic arm are analysed. The robot arm model was created using Solidworks software, and the URDF model file of the robot arm was exported through the sw2urdf plugin conversion tool, and the parameters were configured. Based on ROS for 6-degree-of-freedom (DOF) robot motion simulation, random extended tree (RRT) algorithm from open motion planning library (OMPL) is selected. The robot motion planning analysis and sorting manipulator drive UR5 manipulator. The results show that the sorting pose and motion trajectory of the robot arm are determined by controlling the sorting pose of the sorting robot arm, and the maximum radius value of the tool centre point (TCP) rotation of the robot arm and the position of the workpiece are obtained. This method can improve the success rate of industrial sorting robots in grabbing objects. This analysis is of great significance to the research of robots’ autonomous object grabbing.

Performance Indices for Collaborative Serial Robots With Optimally Adjusted Series Clutch Actuators

2010 ◽  
Author(s):  
Nicolas Lauzier ◽  
Cle´ment Gosselin
Keyword(s):  
Performance Indices ◽  
End Effector ◽  
Robot Architecture ◽  
Serial Robots ◽  
In Series ◽  
Tool Centre Point ◽  
The Relationship ◽  
Architecture Optimization ◽  
Joint Limit

Safety is the first priority when designing robots that are intended to physically interact with humans. New robotics standards state as a condition for collaboration that the robot should be designed so that it cannot exert forces larger than 150[N] at its tool centre point. An effective and reliable way of guaranteeing that this force cannot be exceeded is to place a torque limiter in series with each actuator, thus forming Series Clutch Actuators (SCAs). Since the relationship between the joint limit torques and the achievable end-effector forces is configuration dependent, it is preferable to use adjustable torque limiters. This paper presents a method to optimally control the limit torques of a serial manipulator equipped with adjustable series clutch actuators. It also introduces two performance indices to evaluate the quality of the relationship between the joint limit torques and the achievable end-effector forces. The first one is the ratio of the minimum and maximum force thresholds. Even if it has a strong physical meaning, it is not differentiable everywhere in the workspace and is thus difficult to use in an optimization process based on its gradient. A second index, smooth and expressed in a closed-form, is therefore introduced which is the determinant of the normalized Jacobian matrix post-multiplied by its transposed. Examples of redundant manipulator motion optimization and of collaborative robot architecture optimization using the second index are shown. Finally, the main limitations of the proposed methods and indices are discussed.

scholarly journals Simulative Study of Different Control Concepts of Cooling System for Machine Tools

2018 ◽  
Vol 220 ◽  
pp. 08002
Author(s):  
Linart Shabi ◽  
Juliane Weber ◽  
Jürgen Weber
Keyword(s):  
System Design ◽  
Machine Tools ◽  
Cooling System ◽  
Volume Flow ◽  
Power Losses ◽  
Cooling Systems ◽  
New Concepts ◽  
Temperature Development ◽  
The Individual ◽  
Tool Centre Point

Power losses in machine tools, e.g. during the standby, idle-, and manufacturing process, are converted into heat energy. This causes the machine frame and other machine components to heat up. As a result, the Tool Centre Point (TCP) of the machine tools is moved. The accuracy of the machine is thus reduced during manufacturing. The current cooling system design of machine tools is based on a centrally fixed pump supply that provides a constant cooling volume flow for cooling all the machine tool components. This does not correspond to the individual temperature development of the components, after all, the high temperature fluctuation arises and causes the thermo-elastic deformation of machine tools. The main objective of this paper is to highlight the deficit of the current concept of cooling systems and to present a simulative study on the different controls concepts of cooling systems for machine tools. The results depict that the new concepts under consideration have a large potential for better thermal behaviour and lower hydraulic performance compared to the current cooling system design. The simulation results show a stability of the components’ temperature profile as well as a decreased energy consumption of the cooling system.

scholarly journals Investigation of the negative influence of cooling lubricants on the deformation of the machine tool structure

2019 ◽  
Vol 95 ◽  
pp. 04006
Author(s):  
Christian Brecher ◽  
Filippos Tzanetos ◽  
Daniel Zontar
Keyword(s):  
Machine Tool ◽  
Thermal State ◽  
Negative Impact ◽  
Negative Influence ◽  
Work Piece ◽  
Ongoing Research ◽  
Thermally Induced ◽  
Machine Tool Structure ◽  
Tool Centre Point ◽  
The Impact

Cooling lubricants have a significant influence on the thermal state of a machine tool. The fluid absorbs the thermal energy of the cutting process and dissipates it to prevent wear of the tool and distortion of the work piece. However, the unpredictable flow of the cooling lubricant also transfers the energy to the machine tool structure and can thus have a negative impact on the produced work piece quality. While the thermal behaviour of machine tools under the influence of thermal environmental conditions is already the subject of ongoing research projects, the influence of cooling lubricants on the thermal state of the machine tool and thus the achievable manufacturing accuracy is still largely unexplored. This paper investigates the thermally induced deformations of the machine tool structure, as well as the impact on the Tool Centre Point (TCP).

scholarly journals Kinematically Coupled Force Compensation—Experimental Results and Advanced Design for the 1D-Implementation

2019 ◽  
Vol 3 (1) ◽  
pp. 24
Author(s):  
Steffen Ihlenfeldt ◽  
Jens Müller ◽  
Marcel Merx ◽  
Christoph Peukert
Keyword(s):  
Experimental Investigations ◽  
Future Research ◽  
The Novel ◽  
Test Bed ◽  
Novel Approach ◽  
Reaction Forces ◽  
Tool Centre Point ◽  
And Control ◽  
Machine Structure ◽  
Force Compensation

Typically, the feed dynamics of machine tools are limited to reduce excitations of machine structure oscillations. Consequently, the potential increase in productivity provided by electrical direct drives cannot be exploited. The novel approach of the Kinematically Coupled Force Compensation (KCFC) combines the principles of redundant axes and force compensation to achieve an increase in the machine’s feed dynamics. Because the drive reaction forces are directly applied to the machine frame, they cancel out each other perfectly if the relative motion at the Tool Centre Point (TCP) is split according to the mass ratio of the slides. In this paper, the principle of KCFC is introduced briefly and possible improvements in the design of machine structures and control are presented. The results of experimental investigations obtained by means of a 1D-KCFC Test Bed illustrate the effectiveness of the principle. Moreover, a further increase of the compensation quality can be achieved by decoupling the force flow from the machine frame, by means of elastic elements. Finally, an outlook on future research with reference to the 1D-implementation as well as possible applications of the KCFC in highly productive processes is given.

Structural Nonlinearity of Robotic Machining Systems

2020 ◽  
Author(s):  
Yaser Mohammadi ◽  
Keivan Ahmadi
Keyword(s):  
Dynamic Response ◽  
Industrial Robots ◽  
Mode Analysis ◽  
Cnc Machine Tools ◽  
Modal Parameters ◽  
Cnc Machine ◽  
Workpiece Material ◽  
Robotic Machining ◽  
Machining Vibrations ◽  
Tool Centre Point

Abstract Excessive and unstable vibrations that are caused by the machining forces are among the most critical problems that limit the use of industrial robots instead of CNC machine tools. Reduction and control of robot’s vibrations during machining require accurate models of the robot’s vibration response to the dynamic forces exerted at the Tool Centre Point (TCP) where the cutting tool interacts with the workpiece material. The existing models of vibrations in robotic machining have been formed by assuming the linearity of the dynamic response at the TCP. In this paper, the accuracy of this assumption is investigated experimentally, and the results show that the dynamic response at the TCP is strongly nonlinear. An experimental procedure is presented to identify the nonlinearities by employing the first-order Frequency Response Functions (FRFs) measured using various input force excitations. Nonlinear Complex Mode Analysis is then used to extract the modal parameters of the system when its dynamics is linearized around a harmonic response with a constant amplitude. The extracted modal parameters strongly depend on the amplitude of the applied force and the resulting vibrations. This study highlights the need for considering the nonlinearities of the structural dynamics of industrial robots in modelling machining vibrations.

Analytical Modelling of Temperature Distribution Using Potential Theory by Reference to Broaching of Nickel-Based Alloys

2013 ◽  
Vol 769 ◽  
pp. 139-146 ◽  
Author(s):  
Sascha Gierlings ◽  
Matthias Brockmann
Keyword(s):  
Metal Cutting ◽  
Temperature Fields ◽  
Aviation Industry ◽  
Work Piece ◽  
Machined Surface ◽  
Tool Wear Mechanisms ◽  
Critical Components ◽  
Aero Engines ◽  
Tool Centre Point ◽  
Cutting Processes

Knowledge of temperature fields and heat flow evolving during metal cutting processes is of significant importance for ensuring and predicting the product`s quality. Furthermore, this knowledge enables an improved usage of resources, such as machine tools and tool deployment. The strength of the heat sources as a result of the process and the distribution of the temperature in the material directly influence the tool wear mechanisms, wear rate, thermo-elastic deflection of the tool centre point and the amount of heat flowing into the newly generated work piece surface. Especially the latter effect is of crucial importance when it comes to safety critical components as they are employed in aero-engines. In aviation industry, the surface integrity is used as a complex quality measure summarising several aspects at the machined surface and sub-surface out of which many issues are predominantly thermal issues (e.g. temperature driven hardening of the work piece material, re-cast and white etching layers as well as residual stress profiles).

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