Modelling and control of rigid-flexible multibody systems is studied in this paper. As a specified application, a space robotic system with flexible appendages during a cooperative object manipulation task is consider...
Modelling and control of rigid-flexible multibody systems is studied in this paper. As a specified application, a space robotic system with flexible appendages during a cooperative object manipulation task is considered. This robotic system necessitates delicate force exertion by several end-effectors to move an object along a desired path. During such maneuvers, flexible appendages like solar panels may get stimulated and vibrate. This vibrating motion will cause some oscillatory disturbing forces on the spacecraft, which in turn produces error in the motion of the end-effectors of the cooperative manipulating arms. In addition, vibration control of these flexible members to protect them from fracture is another challenging problem in an object manipulation task for the stated systems. Therefore, the multiple impedance control algorithm is extended to perform an object manipulation task by such complicated rigid-flexible multibody systems. This extension in the control algorithm considers the modification term which compensates the disturbing forces due to vibrating motion of flexible appendages. Finally, a space free-flying robotic system which contains two 2-DOF planar cooperative manipulators, appended with two highly flexible solar panels, is simulated. Obtained results reveal the merits of the developed model-based controller which will be discussed.
This paper presents the identification process of the electric propulsion system for Unmanned Aerial Vehicles. Prepared identification test rig was described in details. It allows to control the electric motor with a ...
This paper presents the identification process of the electric propulsion system for Unmanned Aerial Vehicles. Prepared identification test rig was described in details. It allows to control the electric motor with a propeller and to measure the parameters like thrust force, torque, current and supply voltage, that were used during identification. The worked out and presented identification test helps to check and verify the electric propulsion properties and to develop more accurate simulation models of UAVs.
The paper presents a simple method for obstacle detection and avoidance. The system can be applied for unmanned multirotors and is based on laser scanner detections. What is more, the proposed system supports the pilo...
The paper presents a simple method for obstacle detection and avoidance. The system can be applied for unmanned multirotors and is based on laser scanner detections. What is more, the proposed system supports the pilot during the manual flights. The proposed simple obstacle detection and avoidance algorithm was described in details. The main aim of the work was the in-flight test. The results were presented in the UAV trajectories plot and PWM control signal time plots. Obtained results validate the effectiveness of the proposed collision avoidance method. The described approach helps to ensure collision free conditions for UAV operators.
The paper describes and reviews the research prosecuted on the Mechanical faculty of the Białystok University of Technology on the topic of the autonomous multirotor landing with the computer vision systems. In the fi...
The paper describes and reviews the research prosecuted on the Mechanical faculty of the Białystok University of Technology on the topic of the autonomous multirotor landing with the computer vision systems. In the first section of the article the topic essentials and the motivation for research are described. The following paragraphs are focused over the topic of construction issues and experimental studies over the designed system. The research part is divided into the two sections concentrated respectively over the vision algorithms comparison and the in-flight performance. The results are described in the context of the further advancements and research.
This paper presents the application of a new method for controlling the formation flight of Unmanned Aerial Vehicles. Proposed algorithm is based on the leader follower configuration and uses the potential field to de...
This paper presents the application of a new method for controlling the formation flight of Unmanned Aerial Vehicles. Proposed algorithm is based on the leader follower configuration and uses the potential field to determinate desired heading for the follower UAV. Synthesis of the vector field control algorithm is closely described and presented in details. Proposed control system was carefully checked and verified during Hardware in The Loop (HIL) tests. During the HIL flights the longitudinal and lateral positions of the UAVs (Leader and Follower), orientation angles (pitch, roll, yaw), angular velocities (pitch rate, roll rate, yaw rate) and many other flight parameters were stored and logged. Obtained results validate the effectiveness of the potential field based formation flight control method.
This article presents an object tracking algorithm based on information retrieved from the vision system. The proposed was implemented and tested on an unmanned quadrotor. The proposed vision-based object tracking alg...
This article presents an object tracking algorithm based on information retrieved from the vision system. The proposed was implemented and tested on an unmanned quadrotor. The proposed vision-based object tracking algorithm was presented in details. The main aim of this work was the experimental tests of proposed visual servoing method. During the tests the algorithm has been verified under various conditions that assess its quality.
Recently, intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) has also been demonstrated as an imaging tool for applications in neurological and neurovascular diseases. However, the use of single-shot...
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Recently, intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) has also been demonstrated as an imaging tool for applications in neurological and neurovascular diseases. However, the use of single-shot diffusion-weighted echo-planar imaging for IVIM DWI acquisition leads to suboptimal data quality: for instance, geometric distortion and deteriorated image quality at high spatial resolution. Although the recently commercialized multi-shot acquisition methods, such as multiplexed sensitivity encoding (MUSE), can attain high-resolution and high-quality DWI with signal-to-noise ratio (SNR) performance superior to that of the conventional parallel imaging method, the prolonged scan time associated with multi-shot acquisition is impractical for routine IVIM DWI. This study proposes an acquisition and reconstruction framework based on parametric-POCSMUSE to accelerate the four-shot IVIM DWI with 70% reduction of total scan time (13 min 8 s versus 4 min 8 s). First, the four-shot IVIM DWI scan with 17 b values was accelerated by acquiring only one segment per b value except for b values of 0 and 600 s/mm2. Second, an IVIM-estimation scheme was integrated into the parametric-POCSMUSE to enable joint reconstruction of multi-b images from under-sampled four-shot IVIM DWI data. In vivo experiments on both healthy subjects and patients show that the proposed framework successfully produced multi-b DW images with significantly higher SNRs and lower reconstruction errors than did the conventional acceleration method based on parallel imaging. In addition, the IVIM quantitative maps estimated from the data produced by the proposed framework showed quality comparable to that of fully sampled MUSE-reconstructed images, suggesting that the proposed framework can enable highly accelerated multi-shot IVIM DWI without sacrificing data quality. In summary, the proposed framework can make multi-shot IVIM DWI feasible in a routine MRI examination, with reasonable scan time a
Global warming concerns, along with international agreements and regulations, reflect a broader effort to change the public's high energy demand in recent years. Smart public lighting systems are gaining popularit...
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Global warming concerns, along with international agreements and regulations, reflect a broader effort to change the public's high energy demand in recent years. Smart public lighting systems are gaining popularity due to their energy-saving capabilities, reduction in carbon dioxide emissions, and improved public comfort. However, transitioning to smart public lighting requires careful planning and multiple stages. This is not only to accommodate public behavior, revise scenarios, and test citizen acceptance but also due to the necessary infrastructure investments. Smart public lighting incorporates new technologies, often with a breakeven point that takes several years to reach. To promote the widespread adoption of smart public lighting, it is essential to produce relatively expensive components in large quantities and explore cost-effective solutions. This research focuses on investigating a cost-effective photoelectric sensor for smart public purposes. The primary originality of this study lies in identifying a cost-effective photoelectric sensor that can replace technically equivalent but more expensive sensor solutions for indoor and outdoor lighting control purposes.
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