Dynamics of Robot Mechanisms
- PD and PID controllers in analogous position control; their effects on the positioning error and stability. Calculation of the stability borders in the presence of time-delay.
- Digital position control: 1 DoF model, control force and the equation of motion for PD control. Calculation of the stable parameter domain for the gains P and D. Possibilities for the reduction of the positioning error.
- Particular cases of stability loss at the different kinds of borders of the stable domain. Calculation of the vibration frequency. Optimal gain parameter values corresponding to the fastest error decay and the positioning error.
- Fundamental idea of force control, possible control strategies. Stability chart for the digital force control.
- The 2 DoF model and the nonlinear equation of motion of balancing. Stability investigation of the linearized model. The simplest principle for the calculation of the critical reaction time.
- Stability chart of the linear delayed model of balancing. Stability chart when digital PD control is introduced. Critical reaction time and sampling time. The digital effect of quantisation.
- Components of mechanisms, classification of joints and links. Concept and types of kinematic chains, the advantages of each type in the practice.
- Analysis of mechanisms: calculation of the DoF based on the number and type of joints and links. Reasons for the possible contradictions. Alternatives for the calculation of DoFs.
- Calculation of DoF based on the number of independent geometric constraints and the decomposition of mechanisms into groups.
- Basic design tasks with four-bar linkages: link goes through two and three prescribed pose; rocker motion in a given angle range; link goes through two prescribed extreme pose; quick-return mechanisms.
- Geometric description of planar serial manipulators, homogeneous transformations. Goal and execution of the inverse kinematic calculations.
- Equations of motion for planar serial manipulators. Concept of joint forces and joint torques.
- Comparison of the linear feedback control and the inverse dynamics control (concept of nonlinear feedback linearization). Tuning of the control gains in digital inverse dynamics control augmented by linear feedback.
Computational Fluid Dynamics
- Formulate the generic transport equation in integral form, explain the transport equation, and define the convective and conductive fluxes! What do we mean by the conservative property of the finite volume method?
- Describe the elements of a numerical mesh. In which points are the discrete field variables localized in FLUENT system? In which zones should the numerical mesh be refined? What quality requirements are relevant for CFD meshes and how does mesh quality affect the numerical errors? What is the advantage of streamlining the mesh?
- Describe the physical and mathematical meaning of the boundary conditions applicable in the FLUENT system. Which of these options can be applied to compressible and incompressible flows? What approaches are possible for distributing flow between multiple outlets?
- List the density models most commonly used in flow models. How can you estimate the optimum time step size for a compressible and an incompressible model? What do you need to know about modeling natural convection driven by density difference?
- Please define the velocity, time, and length scales of turbulence! Explain the major turbulence model categories! Describe the k-epsilon model equations. What requirements need to be fulfilled by the mesh when using different turbulence models?
- What thermal boundary conditions can be used for walls in a FLUENT system? What do we mean by optical depth? What kind of radiation heat transport models do you know?
- Describe some applications of porous-jump and porous-zone models! What is the advantage of using internal walls? Please give some application examples! Give examples of using user-defined volume sources.
- What approaches do you know for fluid machinery modeling?
- Describe the main sources of errors and uncertainties in CFD! What methods can be used for error estimation? Describe the Richardson extrapolation!
- Temperature dependence of material properties. Structural and thermal boundary conditions.
- Thermal stress in trusses and beams.
- The Duhamel-Neumann material law. Computation of thermal stresses in plane problems.
- Temperature distribution and thermal stresses in thick walled cylinder.
- Thermal stresses in rotating disk and in shrink fitted components.
- The finite element equation of steady-state heat transfer problem and the computation of its terms.
- Finite element computation of thermal stresses. The finite element equation of the structural analysis and the computation of its terms.
- Modelling of convective heat transfer and radiation with finite elements.
- MEMS devices. Thermomechanical modelling of MEMS devices.
- The workflow and the limitations of the 1-way thermo-mechanical coupling.
- Classification of modelling approaches in thermodynamics according to time and space dependence.
- Modes of heat transfer and the underlying phenomena.
- Thermal radiation: its origin and solutions of typical corresponding problems.
- Derivation of the heat conduction equation: the main principles and steps.
- Boundary conditions for the heat conduction equation and the phenomena behind.
- Dimensionless quantities and equations in heat conduction.
- Exact analytical solutions of the heat conduction equation and their importance.
- Approximate analytical solutions of the heat conduction equation and their importance.
- Numerical solutions of heat transfer problems.