The subject of the article is a simulation of heat affected components of a device for deep drawing by extreme conditions in vacuum by high temperatures required for forming of crystallization containers made from thi...
The subject of the article is a simulation of heat affected components of a device for deep drawing by extreme conditions in vacuum by high temperatures required for forming of crystallization containers made from thin molybdenum sheets. The simulation is focused on the distribution of heat in particular components in relation with their shape. There are presented the design of working components and the boundary conditions of transient thermal simulations with the results.
This paper presents the new laboratory test rig of the vertical axis flexible shaft supported by two active magnetic bearings. Behind the motivation of establishing this setup is the control of vibration modes of the ...
This paper presents the new laboratory test rig of the vertical axis flexible shaft supported by two active magnetic bearings. Behind the motivation of establishing this setup is the control of vibration modes of the flexible rotor - shaft assembly, while the rotational speed varies and the unbalanced mass on the whirling disc is introduced to the system. The proposed model is aimed to simulate real operation conditions of the rotating machinery with an applied external load, with a variable structure caused by a change of material properties of the rotor - shaft assembly, or due to a fault of some elements coupled with the rotor.
In this work we aim to explore the concept of using the shift in the center of gravity, which in turn produces roll and pitch moments, to control the attitude of the quadrotor. We propose constructing a UAV with movin...
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ISBN:
(纸本)9781467383479
In this work we aim to explore the concept of using the shift in the center of gravity, which in turn produces roll and pitch moments, to control the attitude of the quadrotor. We propose constructing a UAV with moving masses within each rotor arm. In this paper we show the mathematical equations describing the dynamics of the proposed system, propose a classical PID based control approach and analyze and confirm its stability. Furthermore, we analyze the effectiveness of the proposed controller in a Gazebo based simulation environment. Finally, we build a laboratory testbed that emulates the dynamics of the system and test our proposed control strategy.
This paper presents a first step of our research on designing an effective and efficient GP-based method for symbolic regression. First, we propose three extensions of the standard Single Node GP, namely (1) a selecti...
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This paper describes the process of the development and improvement of the altitude and vertical velocity estimation algorithm. The previous method was developed by authors two years back. After a diagnosis of pressur...
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This paper describes the process of the development and improvement of the altitude and vertical velocity estimation algorithm. The previous method was developed by authors two years back. After a diagnosis of pressure temperature drift caused by the main IMU, the additional barometric sensor was introduced. Based on readings from this reference component, three main modifications were developed to the algorithm's structure. In addition, three experimental sequences are presented to compare the previous approach with new ones. Results showed that new methods achieve better performance and are free from pressure drift caused by sensor's heating. Decreasing frequency of altitude measurements in Kalman filter resulted in more robust estimates for pressure changes not related to the vertical movement in indoor and outdoor flights. With properly working estimation algorithm, there is a possibility to develop a controller to maintain desired altitude or vertical velocity.
In this paper we present our ongoing efforts to build a heavy lift multirotor platform capable of lifting over 50kg of payload. Such a system requires a paradigm shift in the design of the UAV. Therefore we propose us...
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ISBN:
(纸本)9781467393355
In this paper we present our ongoing efforts to build a heavy lift multirotor platform capable of lifting over 50kg of payload. Such a system requires a paradigm shift in the design of the UAV. Therefore we propose using miniature two stroke internal combustion engines to supply the necessary lift and endurance and combine them with a novel control concept based on the variations of the center of gravity (CoG) of the system. In this paper we present a detailed stability and sensitivity analysis of the proposed control scheme and discuss its underlining effect on the construction design parametrization. We present simulation results from a Gazebo based simulator that confirm the results of our mathematical analysis.
In this paper we present a study of a robotic system that consists of an unmanned aerial vehicle equipped with a pair of manipulator arms (MMUAV), and unmanned ground vehicles (UGVs). The envisioned application scenar...
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ISBN:
(纸本)9781467380270
In this paper we present a study of a robotic system that consists of an unmanned aerial vehicle equipped with a pair of manipulator arms (MMUAV), and unmanned ground vehicles (UGVs). The envisioned application scenario includes autonomous packet transportation, where MMUAV is used for picking/placing packets, while both MMUAV and UGV can be used for packet transportation, with different energy consumption profiles. We propose a reactive method for decentralized task planning and coordination of robots using hierarchical task decomposition based on TAEMS framework. Our approach takes into account low-level motion-planning aspects of the system as well as high-level mission specification, making this a multi-layered system. For low-level planning we use sampling-based planner combined with obstacle-free trajectory generation. Methods are verified in simulations and on an experimental testbed, using 3D robotics quadcopter and Pioneer 3DX mobile robots with the results showing stability and robustness of the presented methods.
In this paper, second-order systems in the presence of both uncertainties and disturbances are considered. It is revealed that super-twisting controllers based on high-order sliding mode observers cannot be implemente...
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In this paper, second-order systems in the presence of both uncertainties and disturbances are considered. It is revealed that super-twisting controllers based on high-order sliding mode observers cannot be implemented when uncertainties are taken into account. An output feedback control law adopting the twisting algorithm is designed such that a Lipschitz continuous as well as saturated control signal is introduced to the system. In order to illustrate the feasibility and effectiveness of the proposed approach, numerical simulations are employed.
In this study, the dynamics and control aspects of a spherical rolling robot's lateral motion are investigated. An approximate, simplified to a single plane, mathematical model is derived using Lagrange equations ...
In this study, the dynamics and control aspects of a spherical rolling robot's lateral motion are investigated. An approximate, simplified to a single plane, mathematical model is derived using Lagrange equations to check stability of the system. Utilizing the fusion of sensor data, a precise orientation measurement is achieved. Document focuses on a synthesis of a PID controller reducing sideway oscillations that occur in motion of a spherical robot with internal pendulum mechanism.
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