scholarly journals Development and validation of a dynamic model for a two-stage speed-reducer

2021 ◽  
Vol 347 ◽  
pp. 00030
Author(s):  
Nicholas J. Tutt ◽  
Martin P. Venter ◽  
Daniel N.J. Els
Keyword(s):  
Dynamic Model ◽  
Degree Of Freedom ◽  
Mesh Stiffness ◽  
Two Stage ◽  
Speed Reducer ◽  
Six Degree Of Freedom ◽  
Development And Validation

This paper presents the development and validation of a six degree of freedom (DOF) dynamic model of a two-stage parallel shaft gearbox, without flaws, which is able to determine the reaction of gearbox components to varying torque inputs and loads. The model utilises flexible shafts and gears rather than using a rigid assumption, to further understand the effect of varying mesh stiffness. The paper replicates the results presented by Diehl and Tang, and improves the number of frequencies that can be analysed. The gear meshing frequencies were expected to dominate the result, however due to the use of a sinusoidal approximation of the varying tooth mesh frequency, the presented model shows the additional gear generated frequencies are present and analysable in the data.

Force-based delay compensation for hardware-in-the-loop simulation divergence of 6-DOF space contact

2017 ◽  
Vol 233 (1) ◽  
pp. 151-165
Author(s):  
Qian Wang ◽  
Chenkun Qi ◽  
Feng Gao ◽  
Xianchao Zhao ◽  
Anye Ren ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Dynamic Models ◽  
Contact Process ◽  
Three Dimensional ◽  
Compensation Method ◽  
Degree Of Freedom ◽  
Hardware In The Loop ◽  
Delay Compensation ◽  
Measurement Delay ◽  
Six Degree Of Freedom

The contact process of a space docking device needs verification before launching. The verification cannot only rely on the software simulation since the contact dynamic models are not accurate enough yet, especially when the geometric shape of the device is complex. Hardware-in-the-loop simulation is a choice to perform the ground test, where the contact dynamic model is replaced by a real device and the real contact occurs. However, the Hardware-in-the-loop simulation suffers from energy increase and instability since time delay is unavoidable. The existing delay compensation methods are mainly focused on a uniaxial or three-dimensional contact. In this paper, a force-based delay compensation method is proposed for the hardware-in-the-loop simulation of a six degree-of-freedom space contact. A six degree-of-freedom dynamic model of the spacecraft motion is derived, and a six degree-of-freedom delay compensation method is proposed. The delay is divided into track delay and measurement delay, which are compensated individually. Experiment results show that the proposed delay compensation method is effective for the six degree-of-freedom space contact.

scholarly journals Six-Degree of Freedom Mathematical Dynamic Model of a Light-Sport Aircraft

2020 ◽  
Vol 886 ◽  
pp. 012011
Author(s):  
Sinchai Chinvorarat ◽  
Boonchai Watjatrakul ◽  
Pongsak Nimdum ◽  
Teerawat Sangpet ◽  
Tosaporn Soontornpasatch ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Degree Of Freedom ◽  
Six Degree Of Freedom

Study on Six-degree of Freedom Mathematical Dynamic Model of a Light Sport Aircraft

2021 ◽  
pp. 37-48
Author(s):  
Sinchai Chinvorarat ◽  
Boonchai Watjatrakul ◽  
Pongsak Nimdum ◽  
Teerawat Sangpet ◽  
Tosaporn Soontornpasatch ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Degree Of Freedom ◽  
Six Degree Of Freedom

Effects of Aerodynamics on Line Sail During Parachute Deployment

2021 ◽  
Author(s):  
Mingzhang Tang ◽  
Liwu Wang ◽  
Yu Liu ◽  
Sijun Zhang
Keyword(s):  
Rigid Body ◽  
Dynamic Model ◽  
Space Vehicle ◽  
Degree Of Freedom ◽  
Recovery System ◽  
On Line ◽  
Parachute System ◽  
Six Degree Of Freedom ◽  
Three Degree Of Freedom ◽  
Mass Spring

Abstract This paper presents a dynamic model to numerically simulate the parachute deployment for space vehicle recovery system. In the proposed dynamic model, the deployment bag and the space vehicle are treated as a six-degree-of-freedom rigid body with mass varied and a regular six-degree-of-freedom rigid body, respectively. The parachute system is considered as the mass spring damper model, in which the canopy, suspension lines, risers and bridles are discretized into some three-degree-of-freedom segments with their centralized mass on the end points. During the deployment a notable phenomenon can be observed and so-called line sail. The line sail generally occurs during a deployment in which the relative wind is not parallel to the deployment direction. The line sail has been known to cause or contribute to the following problems: increased deployment times, changes in snatch load, asymmetrical deployment, friction damage, and unpredictable canopy inflation. To understand its mechanisms, the effects of aerodynamics such as angle of flight path, deployment bag ejection velocity, Mach number, air density and wind velocity are numerically investigated.

Dynamic Modeling of a Six Degree-of-Freedom Flight Simulator Motion Base

2015 ◽  
Vol 10 (5) ◽  
Author(s):  
Mauricio Becerra-Vargas ◽  
Eduardo Morgado Belo
Keyword(s):  
Closed Form ◽  
Dynamic Model ◽  
Kinematic Model ◽  
Closed Form Solution ◽  
Stewart Platform ◽  
Degree Of Freedom ◽  
Dynamic Equations ◽  
Flight Simulator ◽  
Simulator Motion ◽  
Six Degree Of Freedom

This paper presents a closed-form solution for the direct dynamic model of a flight simulator motion base. The motion base consists of a six degree-of-freedom (6DOF) Stewart platform robotic manipulator driven by electromechanical actuators. The dynamic model is derived using the Newton–Euler method. Our derivation is closed to that of Dasgupta and Mruthyunjaya (1998, “Closed Form Dynamic Equations of the General Stewart Platform Through the Newton–Euler Approach,” Mech. Mach. Theory, 33(7), pp. 993–1012), however, we give some insights into the structure and properties of those equations, i.e., a kinematic model of the universal joint, inclusion of electromechanical actuator dynamics and the full dynamic equations in matrix form in terms of Euler angles and platform position vector. These expressions are interesting for control, simulation, and design of flight simulators motion bases. Development of a inverse dynamic control law by using coefficients matrices of dynamic equation and real aircraft trajectories are implemented and simulation results are also presented.

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