Modeling and control of constrained flexible joint parallel manipulators

Download
2010
Oğan, Osman Can
The purpose of the thesis is to achieve a hybrid force and motion control method of parallel manipulators working in a constrained environment, in the presence of joint flexibility that occurs at the actuated joints. A flexible joint is modeled and the equations of motion of the parallel manipulator are derived by using the Lagrange formulation. The structural damping of the active joints, viscous friction at the passive joints and the rotor damping are also considered in the model. It is shown that in a flexible joint manipulator, the acceleration level inverse dynamic equations are singular because the control torques do not have instantaneous effect on the manipulator end-effector contact forces and accelerations due to the flexibility. Implicit numerical integration methods are utilized for solving the singular equations. As a case study, a two legged constrained planar parallel manipulator with three degrees of freedom is simulated to illustrate the performance of the method.

Suggestions

Singularity robust inverse dynamics of planar 2-RPR parallel manipulators
Ider, SK (SAGE Publications, 2004-07-01)
In planar parallel robots, limitations occur in the functional workspace because of interference of the legs with each other and because of drive singularities where the actuators lose control of the moving platform and the actuator forces grow without bounds. A 2-RPR (revolute, prismatic, revolute joints) planar parallel manipulator with two legs that minimizes the interference of the mechanical components is considered. Avoidance of the drive singularities is in general not desirable since it reduces the ...
Analysis of thin walled open section tapered beams using hybrid stress finite element method
Akman, Mehmet Nazım; Oral, Süha; Department of Mechanical Engineering (2008)
In this thesis, hybrid stress finite element is formulated for the analysis of the isotropic, thin walled, open section beams with variable cross sections. The beam element has two nodes each having seven degrees of freedom. Assumption of stress field is sufficient to determine the element stiffness matrix. Axial, flexural and torsional effects are taken into account in the analysis. The methodology can be applied both to the tapered and the uniform beams. Throughout this study, firstly element cross-sectio...
Transient dynamic response of viscoelastic cylinders enclosed in filament wound cylindrical composites
Şen, Özge; Turhan, Doğan; Department of Engineering Sciences (2005)
In this study, transient dynamic response of viscoelastic cylinders enclosed in filament wound cylindrical composites is investigated. Thermal effects, in addition to mechanical effects, are taken into consideration. A generalized thermoelasticity theory which incorporates the temperature rate among the constitutive variables and is referred to as temperature-rate dependent thermoelasticity theory is employed. This theory predicts finite heat propagation speeds. The body considered in this thesis consists o...
Analysis of single phase convective heat transfer in microchannels with variable thermal conductivity and variable viscosity
Gözükara, Arif Cem; Güvenç Yazıcıoğlu, Almıla; Department of Mechanical Engineering (2010)
In this study simultaneously developing single phase, laminar and incompressible flow in a micro gap between parallel plates is numerically analyzed by including the effect of variation in thermal conductivity and viscosity with temperature. Variable property solutions for continuity, momentum and energy equations are performed in a coupled manner, for air as a Newtonian fluid. In these analyses the rarefaction effect, which is important for the slip flow regime, is taken into account by imposing slip veloc...
Fully Coupled Smoothed Particle Hydrodynamics-Finite Element Method Approach for Fluid-Structure Interaction Problems With Large Deflections
Dincer, A. Ersin; Demir, Abdullah; Bozkuş, Zafer; Tijsseling, Arris S. (ASME International, 2019-08-01)
In this study, a combination of the smoothed particle hydrodynamics (SPH) and finite element method (FEM) solving the complex problem of interaction between fluid with free surface and an elastic structure is studied. A brief description of SPH and FEM is presented. Contact mechanics is used for the coupling between fluid and structure, which are simulated with SPH and FEM, respectively. In the proposed method, to couple meshfree and mesh-based methods, fluid and structure are solved together by a complete ...
Citation Formats
O. C. Oğan, “Modeling and control of constrained flexible joint parallel manipulators,” M.S. - Master of Science, Middle East Technical University, 2010.