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Ravn, Peter

doi:10.1023/a:1009759826529

Cited by 177 publications

(9 citation statements)

References 20 publications

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“…Material deformation and damping during motion are routinely ignored as well as clearance and lubrication effects [5,7]. Over the last few decades, some authors have studied planar and spatial mechanical systems with clearance joints [8][9][10]. Haines [11] derived equations of motion that describe the contributions at an idealized revolute joint with clearance but with no lubrication present.…”

Section: Introductionmentioning

confidence: 99%

Lubricated revolute joints in rigid multibody systems

et al. 2008

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The main purpose of this work is to present a general methodology for modeling lubricated revolute joints in constrained rigid multibody systems. In the dynamic analysis of journal-bearings, the hydrodynamic forces, which include both squeeze and wedge effects, generated by the lubricant fluid, oppose the journal motion. The hydrodynamic forces are obtained by integrating the pressure distribution evaluated with the aid of Reynolds' equation, written for the dynamic regime. The hydrodynamic forces built up by the lubricant fluid are evaluated from the system state variables and included into the equations of motion of the multibody system. Numerical examples are presented in order to demonstrate the use of the methodologies and procedures described in this work.

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Section: Introductionmentioning

confidence: 99%

Lubricated revolute joints in rigid multibody systems

et al. 2008

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“…If this element is linear, the approach is known as the Kelvin-Voigt model. When the relation is nonlinear, the model is generally based on the Hertz contact law [29] and [44]. In the case of an unlubricated joint, the Hertzian contact force model is an appropriate choice [44].…”

Section: Fig 1 Contact Forces At the Collision Planementioning

confidence: 99%

“…When the relation is nonlinear, the model is generally based on the Hertz contact law [29] and [44]. In the case of an unlubricated joint, the Hertzian contact force model is an appropriate choice [44]. While the original Hertzian model does not include any energy dissipation, an extension by Lankarani and Nikravesh includes energy loss due to internal damping.…”

Section: Fig 1 Contact Forces At the Collision Planementioning

confidence: 99%

Effects of Joint Clearance on the Motion Accuracy of Robotic Manipulators

2018

SV-JME

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Accuracy is one of the key features that improves the quality of robotic manipulators for many industrial and medical applications. Even with an accurate design and manufacturing process, clearance problems in joints cannot be eliminated in articulated systems. This leads to a loss of accuracy in robotic manipulation. In this study, the effects of joint clearance in a robotic system are investigated. The need for the trajectory of end effector is considered to analyse the motion sensitivity. The kinematics and dynamics of a six-DOF robot with joint clearance are evaluated relative to a robot without joint clearance. Different scenarios for clearance values and working periods are performed to fulfil the required motion task. A neural model is also used to predict the trajectory deviations during the working process. The results show that clearance has a significant role in the motion sensitivity of robotic manipulations. Trajectory errors can also be determined by using a dynamic neural predictor with suitable input variables.

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“…Rossoni et al [3] gave the guideline for the design of the deployment mechanism for the ST5 mission, but they still focused on small deployment speed. Wallrapp and Wiedemann [4] studied the deployment of a flexible solar array using modal techniques, but they limited their investigation to the case of small speed. Contribution related to high speed deployment mechanism applied to the deployment of safety structures can be found in Refs.…”

Section: Introductionmentioning

confidence: 99%

“…In 1998, Ravn [8] proposed a study on local dry contact between planar rigid bodies, in which a set of contact forces is computed according to Hertz model. In 2004, Flores et al [9] proposed a 2D revolute clearance joint model with friction and lubrication.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a High-Speed Deployment Slider–Crank Mechanism: A Design Charts Approach

Mariti

Mucino

Pennestrı̀

et al. 2014

Journal of Mechanical Design

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Mechanical and aerospace applications often require that mechanisms deploy in a quick stable and reliable way. The objective of this study is to implement a general optimization procedure to perform a first stage conceptual design of HSD mechanisms, focusing on both kinematics and dynamics. In particular, the authors will focus on the development of design charts. In the very first part of the work, a parametric lumped-mass system will be modeled in order to reduce the number of parameters for the synthesis phase. A correlation will be established between geometry, inertia and initial position to guarantee the maximum value of acceleration during deployment of the deployable arm by means of the principle of virtual work. In the second part of this work, the influence of important factors such as friction and joint clearance on the overall dynamics of the system will be investigated. Finally, a coupled dynamic and structural analysis of the helical spring, that actuates the mechanism, will be carried out in order to achieve optimal performance. The developed charts will also take into account the space limitation requirement, that are often needed for both aerospace and mechanical applications. A final example will summarize all the points covered by this research effort. Results will be validated using the commercial software ABAQUS.

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Untitled

Cited by 177 publications

References 20 publications

Lubricated revolute joints in rigid multibody systems

Lubricated revolute joints in rigid multibody systems

Effects of Joint Clearance on the Motion Accuracy of Robotic Manipulators

Optimization of a High-Speed Deployment Slider–Crank Mechanism: A Design Charts Approach

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