Calibration and Validation of a Rigid Body Kinematic Model of Flexure Hinges

2010 ◽  
pp. 3-10
Author(s):  
R. J. Ellwood ◽  
D. Schütz ◽  
Annika Raatz ◽  
J. Hesselbach
Keyword(s):  
Rigid Body ◽  
Kinematic Model ◽  
Calibration And Validation ◽  
Flexure Hinges ◽  
Body Kinematic

A Methodology for the Kinematic and Unsteady Dynamics Analysis of Bat Flight

2014 ◽  
Author(s):  
Jeffrey Feaster ◽  
Alex Matta ◽  
Francine Battaglia ◽  
Andrew Kurdila ◽  
Rolf Müller ◽  
...  
Keyword(s):  
Rigid Body ◽  
Critical Points ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Dynamics Analysis ◽  
Post Process ◽  
Body Kinematic ◽  
Stereo Triangulation ◽  
The Many ◽  
Bat Wing

A methodology to capture and post-process bat flight 3-D Stereo Triangulation data to formulate an approximated rigid body kinematic model was investigated. Bat flight is unique in nature due to the bats inherent agility and many degrees of freedom when compared to other flying animals. This complexity makes capturing accurate aerodynamic data very difficult. Unlike insects, which utilize few degrees of freedom and a high flap frequency for sustained flight and maneuverability, the agility of bats comes in part from the many degrees of freedom present in the bat wing. In order to better understand the aerodynamics present in bat flight, bats Hipposideridae (Old World leaf-nosed bats) were examined. The trajectories of critical points along the bat wings were recorded using 3D stereo triangulation techniques to capture the complexities of the bat flight. Markers were placed at all the joint locations along the bat wing. The resulting trajectories were then translated into a periodic kinematic model for future computational use.

Dynamic Modeling and Response Analysis of a Planar Rigid-Body Mechanism With Clearance

2019 ◽  
Vol 14 (5) ◽  
Author(s):  
Chen Xiulong ◽  
Jiang Shuai ◽  
Deng Yu ◽  
Wang Qing
Keyword(s):  
Rigid Body ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Contact Force ◽  
Kinematic Model ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Prototype Model ◽  
Force Model ◽  
Normal Contact

In order to understand dynamic responses of planar rigid-body mechanism with clearance, the dynamic model of the mechanism with revolute clearance is proposed and the dynamic analysis is realized. First, the kinematic model of the revolute clearance is built; the amount of penetration depth and relative velocity between the elements of the revolute clearance joint is obtained. Second, Lankarani-Nikravesh (L-N) and the novel nonlinear contact force model are both used to describe the normal contact force of the revolute clearance, and the tangential contact force of the revolute clearance is built by modified Coulomb friction model. Third, the dynamic model of a two degrees-of-freedom (2DOFs) nine bars rigid-body mechanism with a revolute clearance is built by the Lagrange equation. The fourth-order Runge–Kutta method has been utilized to solve the dynamic model. And the effects of different driving speeds of cranks, different clearance values, and different friction coefficients on dynamic response are analyzed. Finally, in order to prove the validity of numerical calculation result, the virtual prototype model of 2DOFs nine bars mechanism with clearance is modeled and its dynamic responses are analyzed by adams software. This research could supply theoretical basis for dynamic modeling, dynamic behaviors analysis, and clearance compensation control of planar rigid-body mechanism with clearance.

Sensitivity of Sensor Locations in a Wearable IMU-based Human Activity Recognition System

2021 ◽  
Author(s):  
Mehdi Ejtehadi ◽  
Amin M. Nasrabadi ◽  
Saeed Behzadipour
Keyword(s):  
Activity Recognition ◽  
Human Activity ◽  
Human Subjects ◽  
Kinematic Model ◽  
Recognition System ◽  
Human Activity Recognition ◽  
The Body ◽  
Measurement Unit ◽  
Body Segments ◽  
Body Kinematic

Abstract Background: The advent of Inertial measurement unit (IMU) sensors has significantly extended the application domain of Human Activity Recognition (HAR) systems to healthcare, tele-rehabilitation & daily life monitoring. IMU’s are categorized as body-worn sensors and therefore their output signals and the HAR performance naturally depends on their exact location on the body segments. Objectives: This research aims to introduce a methodology to investigate the effects of misplacing the sensors on the performance of the HAR systems. Methods: The properly placed sensors and their misplaced variations were modeled on a human body kinematic model. The model was then actuated using measured motions from human subjects. The model was then used to run a sensitivity analysis. Results: The results indicated that the transverse misplacement of the sensors on the left arm and right thigh and the rotation of the left thigh sensor significantly decrease the rate of activity recognition. It was also shown that the longitudinal displacements of the sensors (along the body segments) have minor impacts on the HAR performance. A Monte Carlo simulation indicated that if the sensitive sensors are mounted with extra care, the performance can be maintained at a higher than 95% level.Conclusions: Accurate mounting of the IMU’s on the body impacts the performance of the HAR. Particularly, the transverse position and rotation of the IMU’s are more sensitive. The users of such systems need to be informed about the more sensitive sensors and directions to maintain an acceptable performance for the HAR.

scholarly journals Kinematics of Serial Manipulators

2020 ◽  
Author(s):  
Ivan Virgala ◽  
Michal Kelemen ◽  
Erik Prada
Keyword(s):  
Rigid Body ◽  
Numerical Solutions ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Body Motion ◽  
Robot Kinematics ◽  
Kinematic Modeling ◽  
Open Chain ◽  
Serial Manipulators ◽  
Serial Robot

This book chapter deals with kinematic modeling of serial robot manipulators (open-chain multibody systems) with focus on forward as well as inverse kinematic model. At first, the chapter describes basic important definitions in the area of manipulators kinematics. Subsequently, the rigid body motion is presented and basic mathematical apparatus is introduced. Based on rigid body conventions, the forward kinematic model is established including one of the most used approaches in robot kinematics, namely the Denavit-Hartenberg convention. The last section of the chapter analyzes inverse kinematic modeling including analytical, geometrical, and numerical solutions. The chapter offers several examples of serial manipulators with its mathematical solution.

Kinematic Model of Planetary Roller Screw Mechanism With Run-Out and Position Errors

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Xiaojun Fu ◽  
Geng Liu ◽  
Shangjun Ma ◽  
Ruiting Tong ◽  
Teik C. Lim
Keyword(s):  
Rigid Body ◽  
Body Movement ◽  
Kinematic Model ◽  
Rotation Period ◽  
Fundamental Property ◽  
Transmission Error ◽  
Position Errors ◽  
Proposed Model ◽  
Roller Screw ◽  
Screw Mechanism

A kinematic model of the planetary roller screw mechanism (PRSM) is proposed, which accounts for the run-out errors of the screw, roller, nut, ring gear, and carrier, and the position errors of the nut and the pinhole in the carrier. The roller floating region, which contains all the possible positions of the roller inside the pinhole, is obtained by analyzing the axial clearances between mating thread surfaces and the radial clearance between the roller and carrier. The proposed model is based on the constraint that the set of roller floating region is not empty. Then, the additional rigid-body movement on the nut is derived and the path of motion transfer from the screw to the nut is obtained. According to the fundamental property of rigid-body kinematics, the axial velocity of the nut is derived and the transmission error of the PRSM is calculated. The proposed model is verified by comparing the calculated transmission error with experimental one. The results show that the transmission error of the PRSM with run-out and position errors is cyclic with a period corresponding to the rotation period of the screw and the magnitude of the transmission error can be much larger than the lead error of the screw. Besides, due to the run-out and position errors, the roller can move radially or transversally inside the pinhole of the carrier when the elements in the PRSM are regarded as rigid bodies.

THE DYNAMICS OF THE FOREST CRANE DURING THE LOAD CARRYING

2013 ◽  
Vol 13 (07) ◽  
pp. 1340013 ◽  
Author(s):  
BOGDAN POSIADALA ◽  
PAWEL WARYS ◽  
DAWID CEKUS ◽  
MATEUSZ TOMALA
Keyword(s):  
Rigid Body ◽  
Kinematic Model ◽  
Calculation Model ◽  
Calculation Algorithm ◽  
Dynamic Interactions ◽  
Runge Kutta Method ◽  
Load Carrying ◽  
Machine Elements ◽  
Numerical Program ◽  
Basic Motion

In this paper, the theoretical and calculation model of the forest crane and the lifted load is presented. The model enables the simulation of the motion of the load carried by a forest crane while taking into account the elastic deformations of the boom. The lifted load has been modeled as a 3D rigid body. The application of such a load model enables the simplification and enhancement of the calculation algorithm. The equations describing the coupled motion of the system load and machine elements are presented. The kinematic model enables the analysis of the basic motion of the load as a response of the system to operational control of the forest crane. In order to determine the motion parameters it was assumed that all system elements are rigid. The lifted load is also treated as a rigid body and its motion is the result of the movement of the load suspension point and the dynamic interactions generated during the motion of the system. The presented sample results from the numerical calculations were obtained from the Matlab system. The initial problem has been solved by the Runge–Kutta method. The numerical program has been developed on the basis of the presented model which allows analyzing the motion of load arising from crane operating mechanisms.

Coupled-Field Analysis of the Compliant Slider Mechanism with Rectangle Flexure Hinges Based on ANSYS

2011 ◽  
Vol 189-193 ◽  
pp. 1897-1900
Author(s):  
Lei Duan ◽  
Li Fang Qiu ◽  
Hai Shan Weng ◽  
Zhi Yong Xie
Keyword(s):  
Finite Element ◽  
Rigid Body ◽  
Element Model ◽  
Field Analysis ◽  
Flexure Hinges ◽  
Body Model ◽  
Coupled Field ◽  
Rigid Body Model ◽  
Relationship Of ◽  
The Relationship

The compliant slider mechanism with rectangle flexure hinges was designed, and its pseudo-rigid-body model was built. The theoretical value of the relationship between force and displacement was given after analysis; the electrostatic-structural-coupled field finite element model of this mechanism was also built and analyzed by ANSYS, and the simulation value of the relationship between voltage and displacement was obtained; According to the relationship of voltage and force, the theoretical value was compared with the simulation value. The result indicates that the model is valid and the analysis is correct.

Kinematic Model of Dynamic Drilling Process

2004 ◽  
Author(s):  
Jochem C. Roukema ◽  
Yusuf Altintas
Keyword(s):  
Mathematical Model ◽  
Rigid Body ◽  
Kinematic Model ◽  
Chip Thickness ◽  
Body Motion ◽  
Depth Of Cut ◽  
Force Model ◽  
Drilling Process ◽  
Structural Vibrations ◽  
Radial Depth

A mathematical model of the torsional-axial chatter vibrations in drilling is presented. The model considers the exact kinematics of both rigid body, and coupled torsional and axial vibrations of the drill. The drill is modeled as a pretwisted beam that exhibits axial deflections due to torque and thrust loading. A mechanistic cutting force model is used to model the cutting torque and thrust as a function of feedrate, speed, radial depth of cut, and drill geometry. The drill rotates and feeds axially into the workpiece while the structural vibrations are excited by the cutting torque and thrust force. The exact location of the drill edge is predicted using the model, and the generated surface is digitized at discrete time intervals. The distribution of chip thickness, which is affected by both rigid body motion and structural vibrations, is evaluated by subtracting the presently generated surface from the previous one. The model considers nonlinearities in cutting coefficients, tool jumping out of cut and overlapping of multiple regeneration waves. The dynamic chip thickness obtained from the true kinematics model allows simultaneous prediction of force, torque, power and dimensional form errors left on the surface. The time domain simulation model allows prediction of stability lobes. The paper provides details of the mathematical model, supported by experimental results of both stable and unstable cuts.

Hybrid Approach to Modeling a Flexible Parallel Robot for Vibration Damping

2007 ◽  
Author(s):  
Jens Kroneis ◽  
Steven Liu
Keyword(s):  
Dynamic Models ◽  
Kinematic Model ◽  
Hybrid Approach ◽  
Measurement Data ◽  
Parallel Robot ◽  
Vibration Damping ◽  
Parallel Robots ◽  
Body Kinematic ◽  
Verification Process ◽  
Standard Frame

In this paper a new method for derivation and verification of rigid and flexible body kinematic and dynamic models of complex parallel robots including crank mechanisms is presented. The rigid body kinematic model is based on standard frame transformations and involves holonomic constraints. Lagrange’s equations of the first type are used for the dynamic modeling of the rigid structure. Using Euler-Bernoulli beams and assumed modes method, a new concept for deriving flexible kinematics and dynamics is developed considering configuration-dependent end masses, called effective payloads. Furthermore a vibration analysis is accomplished and a vibration damping strategy for the parallel robot based on input shaping is described. Through the whole verification process MSC.ADAMS models and measurement data of the demonstrator SpiderMill are used.

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