Design, dynamic analysis and experimental evaluation of a hybrid parallel-serial polishing machine with decoupled motions

2021 ◽  
pp. 1-32
Author(s):  
Peng Xu ◽  
Benny C.F. Cheung ◽  
Bing Li ◽  
Chunjin Wang ◽  
Chenyang Zhao
Keyword(s):  
Degrees Of Freedom ◽  
Driving Forces ◽  
Virtual Work ◽  
Accuracy Assessment ◽  
Six Degrees Of Freedom ◽  
Simulation Based ◽  
Rtcp Function ◽  
Functional Extension ◽  
Polishing Tool ◽  
Laboratory Prototype

Abstract In this paper, a novel six degrees-of-freedom (DOF) hybrid kinematic machine (HKM) is designed, analyzed and evaluated for precision polishing. The design adopts a three DOF tripod-based parallel manipulator (PM) to locate the workpiece, a two DOF serial manipulator (SM) to orient the polishing tool and a functional extension limb to provide a redundant DOF for the workpiece with an axially symmetrical shape. Compared with the existing HKMs, the most distinctive feature is that the position and orientation adjustments of the tool with respect to the workpiece are decoupled during the synchronous machining, thus allowing the rotational tool center point (RTCP) function to be conveniently realized. For the developed HKM, the kinematics are studied systematically, including position, velocity, acceleration and workspace. The dynamic model of the PM is derived by employing the principle of virtual work. For a pre-defined trajectory, the required driving forces are obtained through dynamic simulation. Based on these analyses, a laboratory prototype of the HKM is designed and developed. Preliminary accuracy assessment of the HKM is implemented with a double ball-bar and a series of polishing experiments are conducted to show the capacity and feasibility of the developed HKM.

scholarly journals Geometric Non-Linear Approach to Stiffness State of Semi–Rigid Structures

2016 ◽  
Vol 6 (1) ◽  
pp. 63-70
Author(s):  
Moldovan Corina
Keyword(s):  
Degrees Of Freedom ◽  
Virtual Work ◽  
Steel Structures ◽  
Structural Level ◽  
Element Level ◽  
Present Contribution ◽  
Six Degrees Of Freedom ◽  
Non Linear ◽  
Linear Elements ◽  
Global Systems

Abstract Present contribution intends to emphasize the contribution of geometric non-linearity to the stiffness state of semi-rigid multi–storey steel structures. Though semi-rigidity of beam – column connections involves a nonlinearity at constitutive bending momentrelative rotation level, the geometric nonlinearity associated to deformed conFigure uration at element level is less referred to. The main objective of the study is to express the stiffness state of geometric non-linear elements semi-rigidly connected at its ends. Stiffness state is, in its term, expressed by element level stiffness matrix considering the six degrees of freedom of the planar element. Regarding the reference system, both local and global systems are employed allowing a simple and direct transition from element level vectorial relations to their structural level forms. The three fundamental vectorial relations (static equilibrium, kinematic compatibility, material constitutivity) emphasize that the principle of virtual work holds in the case of semi-rigidly connected skeletal structures as well.

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.

An Experiment for the Study of Free-Flying Supercavitating Projectiles

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Peter J. K. Cameron ◽  
Peter H. Rogers ◽  
John W. Doane ◽  
David H. Gifford
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Measurement Techniques ◽  
Theoretical Models ◽  
Dynamics Simulation ◽  
Small Scale ◽  
Successful Operation ◽  
Six Degrees Of Freedom ◽  
Impact Location ◽  
Simulation Based

Applications and research utilizing supercavitation for high-speed underwater flight has motivated study of the phenomenon. In this work, a small scale laboratory experiment for studying supercavitating projectiles has been designed, built, and tested. Similar existing experimental work has been documented in literature but using large, elaborate facilities, or has been presented with ambiguous conclusions from test results. The projectiles were 63.5 mm in length and traveled at speeds on the order of 145 m/s. Measurement techniques are discussed and used to record projectile speed, supercavity dimensions, and target impact location. Experimental observations are compared with a six degrees-of-freedom dynamics simulation based on theoretical models presented in literature for predicting supercavity shape and hydrodynamic forces on the supercavitating projectile during flight. Experimental observations are discussed qualitatively, along with quantitative statistics of the measurements made. Successful operation of the experiment has been demonstrated and verified by agreement with theoretical models.

scholarly journals Frame loads accuracy assessment of semianalytical multibody dynamic simulation methods of a recreational vehicle

2020 ◽  
Vol 50 (2) ◽  
pp. 189-209
Author(s):  
Nicolas Joubert ◽  
Maxime Boisvert ◽  
Carl Blanchette ◽  
Yves St-Amant ◽  
Alain Desrochers ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Accuracy Assessment ◽  
Field Testing ◽  
Center Of Gravity ◽  
Dynamic Simulations ◽  
Six Degrees Of Freedom ◽  
Multibody Dynamic ◽  
Vehicle Loads ◽  
Vehicle Trajectory

Abstract The design of a vehicle frame is largely dependent on the loads applied on the suspension and heavy parts mounting points. These loads can either be estimated through full analytical multibody dynamic simulations, or from semi-analytical simulations in which tire and road sub-models are not included and external vehicle loads, recorded during field testing, are used as inputs to the wheel hubs. Several semi-analytical methods exist, with various modeling architectures, yet, it is unclear how one method over another improves frame loads prediction accuracy. This study shows that a semi-analytical method that constrains the vehicle frame center of gravity movement along a recorded trajectory, using a control algorithm, leads to an accuracy within 1% for predicting frame loads, when compared to reference loads from a full analytical model. The control algorithm computes six degrees of freedom forces and moments applied at the vehicle center of gravity to closely follow the recorded vehicle trajectory. It is also shown that modeling the flexibility of the suspension arms and controlling wheel hub angular velocity both contribute in improving frame loads accuracy, while an acquisition frequency of 200 Hz appears to be sufficient to capture load dynamics for several maneuvers. Knowledge of these loads helps engineers perform appropriate dimensioning of vehicle structural components therefore ensuring their reliability under various driving conditions.

A Method of Saddle Trajectory Simulation Based on ADAMS

2014 ◽  
Vol 687-691 ◽  
pp. 645-648
Author(s):  
Qiang Fu ◽  
Wen Ming Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Complex Space ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Robot Simulation ◽  
Six Degrees Of Freedom ◽  
Trajectory Simulation ◽  
Simulation Based ◽  
Adams Software ◽  
Saddle Shape

Six degrees of freedom in this paper, by using the ADAMS software to realize the industrial robots can make any saddle trajectory simulation, and trajectory parameters, and it is easy to control the generated trajectory of the saddle shape, size and spatial position,which will improve the efficiency of the industrial robot simulation. The method of complex space curve simulation is generic, and can test the coordinate axis displacement, so the executing agency for the actual factory to avoid movement interference has a certain significance.

Revisiting the inverse dynamics of the Gough–Stewart platform manipulator with special emphasis on universal–prismatic–spherical leg and internal singularity

2012 ◽  
Vol 226 (10) ◽  
pp. 2422-2439 ◽  
Author(s):  
Mohamed Afroun ◽  
Antoine Dequidt ◽  
Laurent Vermeiren
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Inverse Dynamics ◽  
Driving Forces ◽  
Stewart Platform ◽  
Inverse Dynamic ◽  
Computational Burden ◽  
Six Degrees Of Freedom ◽  
Leg Kinematics

This article discusses the dynamic modeling for control of Gough–Stewart platform manipulator with special emphasis on universal–prismatic–spherical leg kinematics. Inverse dynamic model of these six degrees of freedom parallel manipulator robots is reviewed, while complete dynamics with true kinematics of universal–prismatic–spherical legs is compared with several models found in the literature. Most existing models have not taken into account some of the legs kinematical effects, namely the legs angular velocity around their axes and the internal singularities due to passive joints; some other used a simplified parameterization to describe the leg kinematics. Furthermore, some kinetic assumption can be used to reduce the computational burden. This article shows the effect of all these simplifications on the driving forces by simulating the different dynamic models for a commercial manipulator and for different sets of geometric and dynamic parameters of manipulator.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

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