A nonlinear six degrees of freedom dynamic model of planetary roller screw mechanism

2018 ◽  
Vol 119 ◽  
pp. 22-36 ◽  
Author(s):  
Xiaojun Fu ◽  
Geng Liu ◽  
Ruiting Tong ◽  
Shangjun Ma ◽  
Teik C. Lim
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Six Degrees Of Freedom ◽  
Roller Screw ◽  
Screw Mechanism

A Three-Dimensional Dynamic Model for Determining the Equilibrium Configurations of Buoyantly Unstable Icebergs

1990 ◽  
Vol 112 (3) ◽  
pp. 253-262
Author(s):  
R. G. Jessup ◽  
S. Venkatesh
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Static Potential ◽  
Initial State ◽  
Model Simulations ◽  
Six Degrees Of Freedom ◽  
Equilibrium Configurations ◽  
Variation Range

This paper describes a dynamic model developed for the purpose of determining the final equilibrium configurations of buoyantly unstable icebergs. The model places no restrictions on the size, shape, or dimensionality of the iceberg, or on the variation range of the configuration coordinates. Furthermore, it includes all six degrees of freedom and is based on a Lagrangian formulation of the dynamic equations of motion. It can be used to advantage in those situations in which the iceberg has a complicated potential function and can acquire enough momentum and kinetic energy in the initial phase of its motion to make its final configuration uncertain on the basis of a static potential analysis. The behavior of the model is examined through several model simulations. The sensitivity of the final equilibrium position to the initial orientation and shape of the iceberg is clearly evident in the model simulations. Model simulations also show that when an iceberg is released from a nonequilibrium initial state, the time taken for it to settle down varies from about 40 s for a growler to nearly 400 s for a large iceberg. While these absolute times may change with better parameterization of the forces, the relative variations with iceberg size are likely to be preserved.

Model-Based Verifying and Design of Autonomous Airship

2011 ◽  
Vol 66-68 ◽  
pp. 1748-1754
Author(s):  
Yu Liu ◽  
Yi Lin Wu
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Boundary Layer Theory ◽  
Wind Effect ◽  
Nonlinear Dynamic Model ◽  
Kirchhoff Equations ◽  
Six Degrees Of Freedom ◽  
Motion Characteristics ◽  
Linearized Model ◽  
Rotational Damping

Based on the Kirchhoff equations, Newton-Euler laws, boundary layer theory and mass definition, the six degrees of freedom dynamic model of airship complete with aerodynamic forces, wind effect is presented. Then, the nonlinear dynamic model is divided into three group equations by restricting airship motion in different planes respectively. The motion characteristics of airship, including stability, the effect of ballast position and rotational damping, are studied using linearized model. The results of simulation verify the correctness of the theoretical analysis and airship design.

scholarly journals Dynamic Model of Planetary Roller Screw Mechanism with Considering Torsional Degree of Freedom

2020 ◽  
Vol 306 ◽  
pp. 01003
Author(s):  
Linping Wu ◽  
Shangjun Ma ◽  
Qi Wan ◽  
Geng Liu
Keyword(s):  
Dynamic Model ◽  
Mechanical Design ◽  
Relative Displacement ◽  
Hertzian Contact ◽  
Torsional Stiffness ◽  
Roller Screw ◽  
Mode Characteristics ◽  
Screw Mechanism ◽  
The Relationship ◽  
Hertzian Contact Theory

To predict accurately the dynamics performance of planetary roller screw mechanism, it is necessary to establish its streamline and engineering-compliant dynamic model, which is the basis of mechanical design and precision control of the system. In this paper, the relative displacement between roller and ring gear along the line of action is deduced and the relationship between nature frequencies and the number of rollers is discussed. Considering the torsional stiffness of all components and the thread mesh stiffness based on the Hertzian contact theory, the purely torsional model for planetary roller screw mechanism is presented to reveal the natural frequencies and vibration mode characteristics of the system. The results show that the natural properties of undamped system in planetary roller screw mechanism are mainly reflected by two typical vibration modes: rotational mode and roller mode.

Multiple-Mode Dynamic Model for Piezoelectric Micro-Robot Walking

2016 ◽  
Author(s):  
Jinhong Qu ◽  
Kenn R. Oldham
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Beam Theory ◽  
Body Motion ◽  
Six Degrees Of Freedom ◽  
Robot Locomotion ◽  
Multiple Mode ◽  
Micro Robot ◽  
Actuation Scheme ◽  
Robot Body

A multiple-mode dynamic model is developed for a piezoelectrically-actuated micro-robot with multiple legs. The motion of the micro robot results from dual direction motion of piezoelectric actuators in the legs, while the complexity of micro robot locomotion is increased by impact dynamics. The dynamic model is developed to describe and predict the micro robot motion, in the presence of asymmetrical behavior due to non-ideal fabrication and variable properties of the underlying terrain. The dynamic model considers each robot leg as a continuous structure moving in two directions derived from beam theory with specific boundary condition. Robot body motion is modeled in six degrees of freedom using a rigid body approximation. Individual modes of the resulting multimode robot are treated as second order linear systems. The dynamic model is tested with a meso-scale robot prototype having a similar actuation scheme as micro-robots. In accounting for the interaction between robot and ground, the dynamic model with first two modes of each leg shows good match with experimental results for the mesoscale prototype, in terms of both magnitude and the trends of robot locomotion with respect to actuation conditions.

scholarly journals Lagrange-method-based dynamic analysis of multi-stage planetary roller screw mechanism

2021 ◽  
Vol 12 (1) ◽  
pp. 471-478
Author(s):  
Xin Li ◽  
Geng Liu ◽  
Xiaojun Fu ◽  
Shangjun Ma
Keyword(s):  
Degrees Of Freedom ◽  
Rotational Velocity ◽  
Axial Component ◽  
Lagrange Method ◽  
Rigid Body Dynamic ◽  
Multi Stage ◽  
Roller Screw ◽  
Screw Mechanism ◽  
Body Dynamic ◽  
Transient And Steady State

Abstract. A rigid-body dynamic model of multi-stage planetary roller screw mechanism (multi-stage PRSM) is proposed in this paper. The structure of multi-stage PRSM is introduced and the motion analysis is presented. The total kinetic energy of the mechanism is calculated. The rotation of the screws and carriers is chosen as generalized degrees of freedom. The generalized forces and motion equations of multi-stage PRSM are derived using the Lagrange method. The transient and steady-state behaviours of multi-stage PRSM are simulated, followed by an analysis of the influence of friction coefficients and thread pitches on the motion and forces acting on the multi-stage PRSM. Taking a two-stage PRSM as an example, the simulation results show that the friction coefficient between screw #1 and screw #2 has a slight effect on efficiency and rotational velocity ratios of carriers to screws. When the sum of the pitches of screws is a constant, the axial component of contact force between screw #1 and roller #1 decreases with the increase in the pitch of screw #1.

Bond graph-based dynamic model of planetary roller screw mechanism with consideration of axial clearance and friction

2017 ◽  
Vol 232 (16) ◽  
pp. 2899-2911
Author(s):  
Shangjun Ma ◽  
Tao Zhang ◽  
Geng Liu ◽  
Jipeng He
Keyword(s):  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Graph Model ◽  
Bond Graph ◽  
Graph Models ◽  
Axial Acceleration ◽  
Roller Screw ◽  
Angular Velocities ◽  
Screw Mechanism ◽  
Axial Clearance

To reveal the dynamic characteristics of planetary roller screw mechanism, a dynamic model of planetary roller screw mechanism is developed in this study, which is based on the bond graph theory that accounts for friction, axial clearance, and screw stiffness. First, the bond graph models of friction, axial clearance, and load distribution are presented. Then, a bond graph model of the entire planetary roller screw mechanism for the dynamic analysis is established using the 20-sim software package, and the dynamic equations are solved using the Runge–Kutta–Fehlberg algorithm. Finally, the axial speed, axial acceleration, and contact force of the components are derived under different axial loads and with different axial clearances. Furthermore, the dynamic friction characteristics at different angular velocities of the screw and the dynamic stiffnesses for different axial clearances are also obtained. The results can provide a theoretical basis for planetary roller screw mechanism design with consideration of dynamic characteristics.

scholarly journals Dynamic Model of Platform Manipulator with Six Degrees of Freedom

2015 ◽  
Vol 15 (05) ◽  
Author(s):  
Anton Lapikov ◽  
Vasily Paschenko ◽  
Pavel Seredin ◽  
Artem Artemev
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Six Degrees Of Freedom

Dynamic Modeling for Bi-Modal, Rotary Wing, Rolling-Flying Vehicles

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Stefan Atay ◽  
Gregory Buckner ◽  
Matthew Bryant
Keyword(s):  
Dynamic Model ◽  
Empirical Data ◽  
Degrees Of Freedom ◽  
Rigorous Analysis ◽  
Complex Dynamic ◽  
Six Degrees Of Freedom ◽  
Motion Data ◽  
Variational Mechanics ◽  
Rotary Wing ◽  
Dynamic Phenomena

Abstract This paper presents a rigorous analysis of a promising bi-modal multirotor vehicle that can roll and fly. This class of vehicle provides energetic and locomotive advantages over traditional unimodal vehicles. Despite superficial similarities to traditional multirotor vehicles, the dynamics of the vehicle analyzed herein differ substantially. This paper is the first to offer a complete and rigorous derivation, simulation, and validation of the vehicle's terrestrial rolling dynamics. Variational mechanics is used to develop a six degrees-of-freedom dynamic model of the vehicle subject to kinematic rolling constraints and various nonconservative forces. The resulting dynamic system is determined to be differentially flat and the flat outputs of the vehicle are derived. A functional hardware embodiment of the vehicle is constructed, from which empirical motion data are obtained via odometry and inertial sensing. A numerical simulation of the dynamic model is executed, which accurately predicts complex dynamic phenomena observed in the empirical data, such as gravitational and gyroscopic nonlinearities; the comparison of simulation results to empirical data validates the dynamic model.

A New Dynamic Model of High-Speed Railway Vehicle Moving on Curved Tracks

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Sen-Yung Lee ◽  
Yung-Chang Cheng
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Six Degrees Of Freedom ◽  
Car Body ◽  
Yaw Angle

A new dynamic model of railway vehicle moving on curved tracks is proposed. In the new model, the motion of the car body is considered and the motion of the truck frame is not restricted by a virtual boundary. Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of an eight degrees of freedom car system—considering the lateral displacement and the yaw angle of each wheelset, the truck frame, and the half car body—moving on curved tracks are derived completely. To illustrate the accuracy of the analysis, the limiting cases are examined. It is shown that the influence of the gyroscopic moment of the wheelsets on the critical hunting speed is negligible. In addition, the influences of the suspension parameters, including those losing in the six degrees of freedom system, on the critical hunting speeds evaluated via the linear and the nonlinear creep models are studied and compared.

Complete dynamic modelling of a moving base 6-dof parallel manipulator

Robotica ◽  
2009 ◽  
Vol 28 (5) ◽  
pp. 781-793 ◽  
Author(s):  
António M. Lopes
Keyword(s):  
Dynamic Model ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Dynamic Modelling ◽  
Six Degrees Of Freedom ◽  
Moving Base ◽  
Generalized Momentum ◽  
In Series ◽  
Robotic Application ◽  
Base Platform

SUMMARYIn this paper a new approach based on the generalized momentum is used to obtain the dynamic model of a six degrees-of-freedom (dof) parallel manipulator. First, the system dynamic equations are obtained supposing the manipulator base platform is fixed. Afterwards, the dynamic model is extended to the case of a moving base platform. This could be important in a macro/micro robotic application, where a small manipulator is attached in series to a big manipulator. Simulation results of a macro/micro robotic system are presented and the contribution of the base platform motion to the total actuating forces is shown.

Sign in / Sign up

Export Citation Format

Share Document