scholarly journals Output Error Methods for Robot Identification

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Mathieu Brunot ◽  
Alexandre Janot ◽  
Francisco Carrillo ◽  
Joono Cheong ◽  
Jean-Philippe Noël
Keyword(s):  
Degrees Of Freedom ◽  
Target Identification ◽  
Industrial Robot ◽  
Computational Time ◽  
Dynamic Identification ◽  
Inverse Dynamic ◽  
Six Degrees Of Freedom ◽  
Output Error ◽  
Modeling Errors ◽  
Regression Techniques

Abstract Industrial robot identification is usually based on the inverse dynamic identification model (IDIM) that comes from Newton's laws and has the advantage of being linear with respect to the parameters. Building the IDIM from the measurement signals allows the use of linear regression techniques like the least-squares (LS) or the instrumental variable (IV) for instance. Nonetheless, this involves a careful preprocessing to deal with sensor noise. An alternative in system identification is to consider an output error approach where the model's parameters are iteratively tuned in order to match the simulated model's output and the measured system's output. This paper proposes an extensive comparison of three different output error approaches in the context of robot identification. One of the main outcomes of this work is to show that choosing the input torque as target identification signal instead of the output position may lead to a gain in robustness versus modeling errors and noise and in computational time. Theoretical developments are illustrated on a six degrees-of-freedom rigid robot.

Application of non-linear H∞ control to the Tetrabot robot manipulator

1998 ◽  
Vol 212 (6) ◽  
pp. 459-465 ◽  
Author(s):  
I Postlethwaite ◽  
A Bartoszewicz
Keyword(s):  
Degrees Of Freedom ◽  
Robot Manipulator ◽  
Industrial Robot ◽  
External Disturbances ◽  
Six Degrees Of Freedom ◽  
Control Scheme ◽  
Non Linear ◽  
Modelling Uncertainties ◽  
Real Robot ◽  
Robotic Application

In this paper, an application of a non-linear H∞ control law for an industrial robot manipulator is presented. Control of the manipulator motion is formulated into a non-linear H∞ optimization problem, namely optimal tracking performance in the presence of modelling uncertainties and external disturbances. Analytical solutions for this problem are implemented on a real robot. The robot under consideration is the six-degrees-of-freedom GEC Tetrabot. Investigations are made into the selection of weights for the H∞ controller and it is shown how different selections of weights affect the Tetrabot performance. The authors believe this to be the first robotic application of nonlinear H∞ control. Comparisons of the proposed control strategy with conventional proportional-derivative and proportional-integral-derivative controllers show favourable performance of the Tetrabot under the new non-linear H∞ control scheme.

scholarly journals Crack Assessment of Wheel Hubs via an Ultrasonic Transducer and Industrial Robot

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4336 ◽  
Author(s):  
Hanming Zhang ◽  
Chunguang Xu ◽  
Dingguo Xiao
Keyword(s):  
Crack Growth ◽  
Ultrasonic Testing ◽  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Ultrasonic Transducer ◽  
Robot Assisted ◽  
Six Degrees Of Freedom ◽  
Crack Location ◽  
Critical Areas ◽  
Growth Assessment

Crack assessment when making fitness-for-service decisions requires a thorough examination of crack location and size in critical areas. An ultrasonic transducer is used for such assessments, but traditional methods cannot cope with complex rotators, such as wheel hubs. We present a model of robot-assisted crack growth assessment in wheel hubs. We integrate a six-degrees-of-freedom (DOF) industrial robot and a turntable to form a robot-assisted ultrasonic testing (UT) system that does not use traditional UT equipment. Ultrasonic beams are focused at certain depths appropriate for achieving maximum sensitivity. We quantitatively analysed wheel hubs with longitudinal and transverse series of pre-cracks, and concluded that our system autonomously detected cracks.

scholarly journals ABB IRB 120-30.6 Build Procedure in RoboDK

2021 ◽  
pp. 256-264
Author(s):  
Sudip Chakraborty ◽  
P. S. Aithal
Keyword(s):  
Design Methodology ◽  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Research Purpose ◽  
Six Degrees Of Freedom ◽  
Simulation Based ◽  
Software Download ◽  
Coordinate Assignment

Purpose: Research on robotics needs a robot to experiment on it. The actual industrial robot is costly. So, the only resort is to use a Robot simulator. The RoboDK is one of the best robot simulators now. It has covered most of the popular industrial robots. Its interface is straightforward. Just open the software, download the robot as we need, and start experiments. Up to that, no issue was found anywhere. However, the problem begins when we want to build the simulated robot by own. Lots of complexity arises like coordinate assignment, rotation not aligned, length mismatch, robot not synced with DH parameter. We begin to find some documents for making the robots. A few bits of the document are present. That is why we research it. After doing that, we prepared this paper for the researcher who wants to develop the simulated robot independently. This paper can be referenced for them. To minimize the complexity of our research, we study an industrial robot, ABB IRB 120-30.6. It is a good and popular robot. It is six degrees of freedom robot. We will use the specification and STEP file from their respective website and build a simulated robot from the STEP file for our research purpose. Design/Methodology/Approach: We will create a simulated robot from ABB IRB 120-30.6 STEP file. To create a robot by own, we took the help of the IRB 120 robot model. To demonstrate as simple as possible, we start with that robot whose default design is already present. We match and tune the joint coordinate based on robot parameters through this experiment. Findings/results: Here, we see how to create a custom robot. Using the IRB 120 robot model, we will create a robot model step by step. Furthermore, it will move it around its axis. Originality/Value: Using this experiment, the new researcher can get valuable information to create their custom robot. Paper Type: Simulation-based Research.

Theory and Experiments on the Compliance Control of Redundant Robot Manipulators

1990 ◽  
Vol 112 (4) ◽  
pp. 653-660 ◽  
Author(s):  
H. Kazerooni ◽  
K. G. Bouklas ◽  
J. Guo
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Robot Manipulators ◽  
Industrial Robot ◽  
Redundant Robot ◽  
Control Approach ◽  
Six Degrees Of Freedom ◽  
The Stability ◽  
Control Methodology ◽  
Theory And Experiments

This work presents a control methodology for compliant motion in redundant robot manipulators. This control approach takes advantage of the redundancy in the robot’s degrees of freedom: while a maximum six degrees of freedom of the robot control the robot’s endpoint position, the remaining degrees of freedom impose an appropriate force on the environment. To verify the applicability of this control method, an active end-effector is mounted on an industrial robot to generate redundancy in the degrees of freedom. A set of experiments are described to demonstrate the use of this control method in constrained maneuvers. The stability of the robot and the environment is analyzed.

Design, testing and evaluation of an end-effector for self-relocation

Robotica ◽  
2015 ◽  
Vol 34 (12) ◽  
pp. 2689-2728 ◽  
Author(s):  
Feng Han ◽  
Kui Sun ◽  
Yu Liu ◽  
Hong Liu
Keyword(s):  
Degrees Of Freedom ◽  
Physical Simulation ◽  
Industrial Robot ◽  
Space Environment ◽  
Air Bearing ◽  
End Effector ◽  
Six Degrees Of Freedom ◽  
Soft Capture ◽  
End Effectors ◽  
Prototype Design

SUMMARYTwo identical end-effectors are indispensable for self-relocation of a space manipulator, which is an effective way of extending its servicing capability. The prototype design is intimately linked to the requirements. The significant features and functionality of the end-effector and its grapple fixture are described, including the key analysis efforts. The characteristics of the end-effector and their suitability for self-relocation and payload handling were confirmed by testing, which used two prototype end-effectors, a semi-physical simulation testbed system with two, six degrees of freedom (DOF) industrial robot arms, and an air-bearing testbed system with a seven DOF manipulator. The results demonstrate that the end-effector satisfies the requirements and it can work well in a simulated space environment. With the compliance motion of the manipulator, the end-effector can perform soft capture and the manipulator can securely self-relocate and handle the payload.

Design of the Hydraulic System for Carrying Manipulator with 6-DOF

2014 ◽  
Vol 989-994 ◽  
pp. 2802-2806
Author(s):  
Min Wang ◽  
Cai Dong Wang ◽  
Hui Zheng ◽  
Guo Feng Fan
Keyword(s):  
Mathematical Model ◽  
Hydraulic System ◽  
Degrees Of Freedom ◽  
Assembly Line ◽  
Industrial Robot ◽  
Structural Parameters ◽  
Hydraulic Cylinder ◽  
Six Degrees Of Freedom ◽  
Output Force ◽  
Working Principle

According to the requirements for wheel hub assembly line, the structure and hydraulic system of carrying manipulator with six degrees of freedom (DOF) is designed. The working principle of the hydraulic system is analyzed. To minimize the output force of the hydraulic cylinder, a mathematical model of hydraulic cylinder output force and structural parameters is established. And then the manipulator structure is optimized based on Matlab software. The key components of the hydraulic system are selected. This research provides reference for design of similar hydraulic system of industrial robot.

Design and Experimental Study of a 6-DOF Material Testing Machine

2013 ◽  
Vol 419 ◽  
pp. 533-542
Author(s):  
Dan Wang ◽  
Rui Fan ◽  
Jiang Zhen Guo ◽  
Wu Yi Chen ◽  
Yong Sheng Sun
Keyword(s):  
Degrees Of Freedom ◽  
Controller Design ◽  
Testing Machine ◽  
Tensile Tests ◽  
Material Testing ◽  
Multiaxial Loading ◽  
Inverse Dynamic ◽  
Six Degrees Of Freedom ◽  
Loading Tests ◽  
Material Testing Machine

A six degrees-of-freedom (DOF) parallel material testing machine (PMTM), which is based on Stewart Platform, is first proposed in this paper. Several essential issues including prototyping, compliant axis determination and controller design are investigated with specific methods or technologies. The compliant axis, along which the proposed machine has a better performance, is determined by the eigenscrew decomposition method. The proposed force controller incorporates the simplified inverse dynamic model output as a model-based portion of the controller and its validity is verified by means of simulations. Evaluation tests are performed to examine the practicability of the proposed controller and to determine the loading accuracy of the PMTM. Tensile tests and preliminary multiaxial loading tests are performed to verify the performance of the proposed PMTM. The experimental results illustrate that the proposed PMTM is capable of performing multiaxial loading tests of materials and thus a suitable candidate for multiaxial material testing machine.

scholarly journals Modelling an Industrial Robot and Its Impact on Productivity

Mathematics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 769
Author(s):  
Carlos Llopis-Albert ◽  
Francisco Rubio ◽  
Francisco Valero
Keyword(s):  
Degrees Of Freedom ◽  
Sliding Mode ◽  
Industrial Robot ◽  
System Stability ◽  
Optimal Time ◽  
Tracking Accuracy ◽  
Six Degrees Of Freedom ◽  
Trade Offs ◽  
Fuzzy Sliding Mode ◽  
Pareto Fronts

This research aims to design an efficient algorithm leading to an improvement of productivity by posing a multi-objective optimization, in which both the time consumed to carry out scheduled tasks and the associated costs of the autonomous industrial system are minimized. The algorithm proposed models the kinematics and dynamics of the industrial robot, provides collision-free trajectories, allows to constrain the energy consumed and meets the physical characteristics of the robot (i.e., restriction on torque, jerks and power in all driving motors). Additionally, the trajectory tracking accuracy is improved using an adaptive fuzzy sliding mode control (AFSMC), which allows compensating for parametric uncertainties, bounded external disturbances and constraint uncertainties. Therefore, the system stability and robustness are enhanced; thus, overcoming some of the limitations of the traditional proportional-integral-derivative (PID) controllers. The trade-offs among the economic issues related to the assembly line and the optimal time trajectory of the desired motion are analyzed using Pareto fronts. The technique is tested in different examples for a six-degrees-of-freedom (DOF) robot system. Results have proved how the use of this methodology enhances the performance and reliability of assembly lines.

scholarly journals A Method to Minimize the Effort for Damper–Blade Matching Demonstrated on Two Blade Sizes

2021 ◽  
Vol 11 (11) ◽  
pp. 5171
Author(s):  
Chiara Gastaldi ◽  
Muzio M. Gola
Keyword(s):  
Degrees Of Freedom ◽  
Turbine Blades ◽  
Contact Forces ◽  
Computational Time ◽  
Linear Solution ◽  
Six Degrees Of Freedom ◽  
Nonlinear Finite Elements ◽  
Bending Stresses ◽  
Order Of Magnitude ◽  
Detailed Application

A method called PCR (Platform Centered Reduction) is designed to more effectively perform complex iterative and nonlinear calculations required for the dynamic response of turbine blades damped by dry friction contacts between rigid dampers and airfoil-to-neck platform. The key feature of PCR is to represent all nonlinear forces on the blade platform by means of only six degrees of freedom at a point located within the platform volume, regardless of the number of damper–platform contact elements. Despite reducing the effort and computational time by more than one order of magnitude, the method proves to be fully accurate by a check against the corresponding nonlinear Finite Elements (FE) calculation. It is also shown that the limit exciting force, indicating the upper capability to dampen vibrations, can be calculated with a simple linear modal analysis. In order to search for the best blade–damper match, the preferred graph represents relevant bending stresses on the airfoil against excitation forces. A detailed application of the method concerns two significantly different blade sizes, by varying parameters such as neck length and damper centrifugal force. Finally, it is emphasized that a final check by a complete FE analysis is still possible as a purely linear solution fed by sets of contact forces previously determined through the PCR at any desired frequency and excitation.

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