|
|
Building and control of 5-axis milling machines
Anderle, Milan ; Knobloch, Josef (referee) ; Holub, Michal (advisor)
This bachelor’s thesis studies the building and control of the five-axis CNC machining centres. Modern methods of geometric accuracy measurements are described with possibilites of compensating for geomeric and volumetric errors. Measuring devices described in this thesis are laser interferometer XL-80 and ballbar QC20-W for measuring geometric accuracy of MCV 754 Quick machine. The aim of the thesis is to describe current trends in construction, design and controlling of five-axis milling machines.
|
|
|
Calcination model developement for ANSYS Fluent
Anderle, Milan ; Hájek, Jiří (referee) ; Vondál, Jiří (advisor)
The aim of the diploma thesis was creating a decarbonisation model of lime, implementation the model into CFD tool ANSYS Fluent and to test the decarbonisation model in a model of a real reactor. The required model was based on assumptions for a Shrinking Core Model (SCM). The main objective of this work was the non-catalytic conversion of substances and the search for the most used mathematical models for calcination. The CFD calculation, the sensitivity analysis and the Fluente parametric study were used. Data on the composition of gas flow, temperature, pressure and mass flow of limestone particles were selected for input variables. The particle model called Multiple Surface Reactions (MSR), which is a standard part of Fluent, was used at first. Subsequently, a UDF which was based on the SCM assumptions was written in the programming language C. The results of the CFD calculation were compared with the experimental values from the dissertation. It has been found that the MSR is sufficiently precise for calculation purposes but neglects the internal diffusion of CO2 through the CaO layer which forms behind the reaction front during calcination. It was found that it is possible to solve the flow with ongoing calcination without the need to know the parameters of the Arrhenian equation if the UDF is used. The created UDF incorporates the influence of intraparticular CO2 diffusion on the overall reaction rate.
|
|
|
COMPUTER SIMULATION STUDY OF THE STABILITY OF UNDERACTUATED BIPEDAL ROBOT MODELS (motivated by Griffin and Grizzle, 2017)
Polach, P. ; Anderle, Milan ; Zezula, Pavel ; Papáček, Štěpán
A key feature for bipedal walkers (robots and humans as well) is their stability or disturbance rejection defined as the ability to deal with unexpected disturbances. The paper by Griffin and Grizzle (2017) have significantly contributed to the shift from flat ground to slopes and steps when evaluating the walking efficiency of their robots. Similarly, in this contribution, based on the appropriate model of robot dynamics and control law, we examine the stability of walking-without-falling for different ground perturbations for a threelink compass gait walker. I.e., we perform the sensitivity analysis of the walking stability of underactuated bipedal walker with respect to certain disturbation using the alaska/MultibodyDynamics simulation tool.
|
|
|
On a class of biped underactuated robot models with upper body: Sensitivity analysis of the walking performance
Papáček, Štěpán ; Polach, P. ; Prokýšek, R. ; Anderle, Milan
Biped underactuated robots with an upper body (being a torso) form a subclass of legged robots. This study deals with the walking performance of such class of legged robot models and has been motivated by the need to implement of the previously developed sensor and control algorithms for the real-time movement of the laboratory walking robot, designed and built at the Department of Control Theory of the Institute of Information Theory and Automation (UTIA) of the Czech Academy of Sciences, see Fig. 1 (left). A detailed description of this underactuated walking-like mechanical system (called further UTIA Walking Robot – UWR) is provided in [2] and [5]. The simplest underactuated walking robot hypothetically able to walk is the so-called Compass gait biped walker, alternatively called the Acrobot, see Fig. 1 (right). For a review of underactuated mechanical systems, i.e. systems with fewer actuators than degrees of freedom, which encounter many applications in different fields (e.g., in robotics, in aeronautical and spatial systems, in marine and underwater systems, and in-flexible and mobile systems), see [3]. As follows, we examine the walking performance of parametrized models for different walking regimes and different values of model parameters. More specifically, the sensitivity analysis (i.e., parameter study) of the walking performance with respect to certain design variables (model parameters) is carried out using the software package alaska/MultibodyDynamics. The main attention is attracted to the role of the upper body mass m3 and position lc3, see Fig. 1 (right). Last but not least, having surveyed the mechanics of planar biped robots, our subsequent goal is the analysis of a 3D biped model where lateral balance is either controlled, suppressed or compensated.
|
|
|
Calcination model developement for ANSYS Fluent
Anderle, Milan ; Hájek, Jiří (referee) ; Vondál, Jiří (advisor)
The aim of the diploma thesis was creating a decarbonisation model of lime, implementation the model into CFD tool ANSYS Fluent and to test the decarbonisation model in a model of a real reactor. The required model was based on assumptions for a Shrinking Core Model (SCM). The main objective of this work was the non-catalytic conversion of substances and the search for the most used mathematical models for calcination. The CFD calculation, the sensitivity analysis and the Fluente parametric study were used. Data on the composition of gas flow, temperature, pressure and mass flow of limestone particles were selected for input variables. The particle model called Multiple Surface Reactions (MSR), which is a standard part of Fluent, was used at first. Subsequently, a UDF which was based on the SCM assumptions was written in the programming language C. The results of the CFD calculation were compared with the experimental values from the dissertation. It has been found that the MSR is sufficiently precise for calculation purposes but neglects the internal diffusion of CO2 through the CaO layer which forms behind the reaction front during calcination. It was found that it is possible to solve the flow with ongoing calcination without the need to know the parameters of the Arrhenian equation if the UDF is used. The created UDF incorporates the influence of intraparticular CO2 diffusion on the overall reaction rate.
|
|
|
Building and control of 5-axis milling machines
Anderle, Milan ; Knobloch, Josef (referee) ; Holub, Michal (advisor)
This bachelor’s thesis studies the building and control of the five-axis CNC machining centres. Modern methods of geometric accuracy measurements are described with possibilites of compensating for geomeric and volumetric errors. Measuring devices described in this thesis are laser interferometer XL-80 and ballbar QC20-W for measuring geometric accuracy of MCV 754 Quick machine. The aim of the thesis is to describe current trends in construction, design and controlling of five-axis milling machines.
|
|
|
Comparison of Nonlinear Observers for Underactuated Mechanical Systems
Anderle, Milan ; Čelikovský, Sergej
This paper provides the comparison of nonlinear observers for underactuated mechanical systems with aplication to Acrobot walking. Namely, it aims to compare a reduced observer for the Acrobot angular velocities based on the respective angles measurements with a observer for the Acrobot angular velocity and angle based on the other angular velocity and angle measurement and then to combine this observers with the earlier developed full state feedback controllers. For the Acrobot it is not possible to measure the angle between its stance leg and the surface directly because this angle is underactuated. One possibility of measuring this angle is using laser beam sensor and then computation the stance angle from that distance. Main disadvantage of this approach is the high price of the laser beam sensor. The other observer is based on angular velocity of stance leg measurement using the digital gyroscope.
|
guest ::
RSS feed.