An Autonomous Docking Mechanism for Vertical Lift Unmanned Aircraft

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
John Papayanopoulos ◽  
Kevin Webb ◽  
Jonathan Rogers
Keyword(s):  
Measurement Errors ◽  
Closed Loop ◽  
Mechanical Design ◽  
Tracking System ◽  
Unmanned Aircraft ◽  
Wide Range ◽  
Air Vehicle ◽  
Docking Mechanism ◽  
Infrared Tracking ◽  
Autonomous Docking

Abstract Unmanned aerial vehicles are increasingly being tasked to connect to payload objects or docking stations for the purposes of package transport or recharging. However, autonomous docking creates challenges in that the air vehicle must precisely position itself with respect to the dock, oftentimes in the presence of uncertain winds and measurement errors. This paper describes an autonomous docking mechanism comprising a static ring and actuated legs, coupled with an infrared tracking device for closed-loop docking maneuvers. The dock’s unique mechanical design enables precise passive positioning such that the air vehicle slides into a precise location and orientation in the dock from a wide range of entry conditions. This leads to successful docking in the presence of winds and sensor measurement errors. A closed-loop infrared tracking system is also described in which the vehicle tracks an infrared beacon located on the dock during the descent to landing. A detailed analysis is presented describing the interaction dynamics between the aircraft and the dock, and system parameters are optimized through the use of trade studies and Monte Carlo analysis with a three degree-of-freedom simulation model. Experimental results are presented demonstrating successful docking maneuvers of an autonomous air vehicle in both indoor and outdoor environments. These repeatable docking experiments verify the robustness and practical utility of the dock design for a variety of emerging applications.

Autonomous Docking of Hybrid-Wheeled Modular Robots with an Integrated Active Genderless Docking Mechanism

2021 ◽  
pp. 1-36
Author(s):  
Shubhdildeep S. Sohal ◽  
Bijo Sebastian ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Visual Servoing ◽  
Mechanical Design ◽  
Low Cost ◽  
Image Plane ◽  
Robotic Systems ◽  
Modular Robots ◽  
Tracking Accuracy ◽  
Drive Mechanism ◽  
Docking Mechanism ◽  
Autonomous Docking

Abstract This paper presents a self-reconfigurable modular robot with an integrated 2-DOF active docking mechanism. Active docking in modular robotic systems has received a lot of interest recently as it allows small versatile robotic systems to coalesce and achieve the structural benefits of large systems. This feature enables reconfigurable modular robotic systems to bridge the gap between small agile systems and larger robotic systems. The proposed self-reconfigurable mobile robot design exhibits dual mobility using a tracked drive mechanism for longitudinal locomotion and a wheeled drive mechanism for lateral locomotion. The 2-DOF docking interface allows for efficient docking while tolerating misalignments. To aid autonomous docking, visual marker-based tracking is used to detect and re-position the source robot relative to the target robot. The tracked features are then used in Image-Based Visual Servoing to bring the robots close enough for the docking procedure. The hybrid-tracking algorithm allows eliminating external pixelated noise in the image plane resulting in higher tracking accuracy along with faster frame update on a low-cost onboard computational device. This paper presents the overall mechanical design and the integration details of the modular robotic module with the docking mechanism. An overview of the autonomous tracking and docking algorithm is presented along-with a proof-of-concept real world demonstration of the autonomous docking and self-reconfigurability. Experimental results to validate the robustness of the proposed tracking method, as well as the reliability of the autonomous docking procedure, are also presented.

A closed-loop wide-range tunable mechanical resonator for energy harvesting systems

2009 ◽  
Vol 19 (9) ◽  
pp. 094004 ◽  
Author(s):  
Christian Peters ◽  
Dominic Maurath ◽  
Wolfram Schock ◽  
Florian Mezger ◽  
Yiannos Manoli
Keyword(s):  
Energy Harvesting ◽  
Closed Loop ◽  
Mechanical Resonator ◽  
Wide Range ◽  
Harvesting Systems

Rubber Plastometer with Uniform Rate of Shear—Shearing-Cone Plastometer

1946 ◽  
Vol 19 (3) ◽  
pp. 822-831 ◽  
Author(s):  
G. H. Piper ◽  
J. R. Scott
Keyword(s):  
Plastic Flow ◽  
Mechanical Design ◽  
Plastic Material ◽  
Edge Zone ◽  
Uniform Rate ◽  
Wide Range

Abstract A new shearing-cone plastometer, suitable for investigating the plastic-flow relations of highly viscous materials over a wide range of stress, is described. A mushroom-shaped rotor, having upper and lower surfaces of conical type, is rotated in the plastic material contained in a cylindrical mould. With this type of shearing surface the rate of shear is uniform throughout the material, except for a small edge zone, thus overcoming some disadvantages of previous plastometers. The mechanical design is based on the Mooney shearing-disk plastometer except that provision is made for a wide range of speeds of rotation.

Integrating Unmanned Aircraft Systems into State Department of Transportation Highway Bridge Inspection Procedures: Challenges, Implications, and Lessons Learned

2021 ◽  
pp. 036119812110444
Author(s):  
Michael Plotnikov ◽  
John Collura
Keyword(s):  
State Department ◽  
Lessons Learned ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Highway Bridge ◽  
Department Of Transportation ◽  
Bridge Inspection ◽  
Aircraft Systems ◽  
Wide Range ◽  
Bridge Inspections

Rapid proliferation of small, unmanned aircraft systems (UAS) promises to revolutionize traditional methods used to carry out civil engineering surveys and analyses and conduct physical infrastructure inspections. One of the most promising areas of implementation of innovative UAS technology includes the integration of UAS into current state Department of Transportation (DOT) bridge inspections. While regular bridge inspections are paramount for road user safety, many traditional inspection methods and procedures are cumbersome, expensive, and time consuming; present significant hazards to both the traveling public and the inspection personnel; and are disruptive to normal operations of the transportation facilities. The results of recent studies indicate that UAS can serve as a useful tool in many highway bridge inspection procedures, while significantly reducing costs and time and improving safety. The major factors that affect the success of integrating UAS into the bridge inspection process relate to selection of the proper types of UAS platforms and avionics, data collection sensors and processing software, as well as conduct of task-specific pilot training. The paper provides an examination of current standard bridge inspection procedures and protocols currently carried out by state DOTs; an evaluation of state DOT experiences with the integration of UAS technology into bridge inspections; and an assessment of the issues and challenges associated with this technology. It is expected that this paper will be of interest to a wide range of stakeholders representing state and federal governments, academia, and industry.

A comparison of traceable spatial angle autocollimator calibrations performed by PTB and VTT MIKES

Metrologia ◽  
2021 ◽  
Author(s):  
Ralf D Geckeler ◽  
Matthias Schumann ◽  
Andreas Just ◽  
Michael Krause ◽  
Antti Lassila ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Measurement Errors ◽  
Systematic Measurement ◽  
Motivating Factors ◽  
Optical Surface ◽  
Transfer Standard ◽  
Surface Normal ◽  
National Metrology Institutes ◽  
Wide Range ◽  
The Creation

Abstract Autocollimators are versatile devices for angle metrology used in a wide range of applications in engineering and manufacturing. A modern electronic autocollimator generally features two measuring axes and can thus fully determine the surface normal of an optical surface relative to it in space. Until recently, however, the calibration capabilities of the national metrology institutes were limited to plane angles. Although it was possible to calibrate both measuring axes independently of each other, it was not feasible to determine their crosstalk if angular deflections were present in both axes simultaneously. To expand autocollimator calibrations from plane angles to spatial angles, PTB and VTT MIKES have created dedicated calibration devices which are based on different measurement principles and accomplish the task of measurand traceability in different ways. Comparing calibrations of a transfer standard makes it possible to detect systematic measurement errors of the two devices and to evaluate the validity of their uncertainty budgets. The importance of measurand traceability via calibration for a broad spectrum of autocollimator applications is one of the motivating factors behind the creation of both devices and for this comparison of the calibration capabilities of the two national metrology institutes. The latter is the focus of the work presented here.

Closed-Loop Control of a Constrained, Resonant-Flapping Micro Air Vehicle

AIAA Journal ◽  
2014 ◽  
Vol 52 (8) ◽  
pp. 1616-1623 ◽  
Author(s):  
Garrison J. Lindholm ◽  
Richard G. Cobb
Keyword(s):  
Closed Loop ◽  
Micro Air Vehicle ◽  
Closed Loop Control ◽  
Loop Control ◽  
Air Vehicle

scholarly journals The Modelling, Simulation and FPGA-Based Implementation for Stepper Motor Wide Range Speed Closed-Loop Drive System Design

Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 56 ◽  
Author(s):  
Chiu-Keng Lai ◽  
Jhang-Shan Ciou ◽  
Chia-Che Tsai
Keyword(s):  
Embedded System ◽  
High Speed ◽  
Closed Loop ◽  
Open Loop ◽  
Drive System ◽  
Stepper Motor ◽  
Motor Drive ◽  
Digital Controllers ◽  
Loop Control ◽  
Wide Range

Owing to the benefits of programmable and parallel processing of field programmable gate arrays (FPGAs), they have been widely used for the realization of digital controllers and motor drive systems. Furthermore, they can be used to integrate several functions as an embedded system. In this paper, based on Matrix Laboratory (Matlab)/Simulink and the FPGA chip, we design and implement a stepper motor drive. Generally, motion control systems driven by a stepper motor can be in open-loop or closed-loop form, and pulse generators are used to generate a series of pulse commands, according to the desired acceleration/run/deceleration, in order to the drive system to rotate the motor. In this paper, the speed and position are designed in closed-loop control, and a vector control strategy is applied to the obtained rotor angle to regulate the phase current of the stepper motor to achieve the performance of operating it in low, medium, and high speed situations. The results of simulations and practical experiments based on the FPGA implemented control system are given to show the performances for wide range speed control.

scholarly journals Reviewing Wind Measurement Approaches for Fixed-Wing Unmanned Aircraft

Atmosphere ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 422 ◽  
Author(s):  
Alexander Rautenberg ◽  
Martin Graf ◽  
Norman Wildmann ◽  
Andreas Platis ◽  
Jens Bange
Keyword(s):  
Wind Speed ◽  
Unmanned Aircraft ◽  
Flow Sensor ◽  
Navigation Satellite ◽  
Wind Vector ◽  
Data Set ◽  
Vector Measurement ◽  
Wide Range ◽  
Global Navigation ◽  
Global Navigation Satellite

One of the biggest challenges in probing the atmospheric boundary layer with small unmanned aerial vehicles is the turbulent 3D wind vector measurement. Several approaches have been developed to estimate the wind vector without using multi-hole flow probes. This study compares commonly used wind speed and direction estimation algorithms with the direct 3D wind vector measurement using multi-hole probes. This was done using the data of a fully equipped system and by applying several algorithms to the same data set. To cover as many aspects as possible, a wide range of meteorological conditions and common flight patterns were considered in this comparison. The results from the five-hole probe measurements were compared to the pitot tube algorithm, which only requires a pitot-static tube and a standard inertial navigation system measuring aircraft attitude (Euler angles), while the position is measured with global navigation satellite systems. Even less complex is the so-called no-flow-sensor algorithm, which only requires a global navigation satellite system to estimate wind speed and wind direction. These algorithms require temporal averaging. Two averaging periods were applied in order to see the influence and show the limitations of each algorithm. For a window of 4 min, both simplifications work well, especially with the pitot-static tube measurement. When reducing the averaging period to 1 min and thereby increasing the temporal resolution, it becomes evident that only circular flight patterns with full racetracks inside the averaging window are applicable for the no-flow-sensor algorithm and that the additional flow information from the pitot-static tube improves precision significantly.

scholarly journals DQ-Frame Admittance Estimation of Three-Phase Converters with a Wide Range of Operating Points

2021 ◽  
Author(s):  
Hong Gong ◽  
xiongfei wang ◽  
Dongsheng Yang
Keyword(s):  
Error Estimation ◽  
Closed Loop ◽  
Estimation Method ◽  
Experimental Results ◽  
Multidimensional Interpolation ◽  
Three Phase ◽  
Wide Range ◽  
Linearized Model ◽  
Operating Points ◽  
Error Estimation Method

The <i>dq</i>-frame admittance of closed-loop controlled three-phase converters is a linearized model that is dependent on the operating points of the system. Yet, it is impractical to measure the converter admittance at all operating points. This paper, thus, proposes an approach to estimating the <i>dq</i>-frame admittance of three-phase converters at a wide range of operating points. The method applies multidimensional interpolation to a given set of admittance data, which is measured from the pre-defined operating points. The accuracy of interpolation is then evaluated by using the posterior error estimation method. The number of pre-defined operating points is next adjusted to find a good compromise between the accuracy and efficiency of the approach. Simulations and experimental results verify the effectiveness of the approach.<div><br></div>

scholarly journals Development of an Advanced Solar Tracking Energy System

2021 ◽  
pp. 77-82
Author(s):  
Samuel Davies ◽  
Sivagunalan Sivanathan ◽  
Ewen Constant ◽  
Kary Thanapalan
Keyword(s):  
Control System ◽  
System Performance ◽  
Mechanical Design ◽  
System Development ◽  
Tracking System ◽  
Energy System ◽  
Design And Implementation ◽  
Solar Tracking ◽  
Advanced Control ◽  
Stability Issues

AbstractThis paper describes the design of an advanced solar tracking system development that can be deployed for a range of applications. The work focused on the design and implementation of an advanced solar tracking system that follow the trajectory of the sun’s path to maximise the power capacity generated by the solar panel. The design concept focussed on reliability, cost effectiveness, and scalability. System performance is of course a key issue and is at the heart of influencing the hardware, software and mechanical design. The result ensured a better system performance achieved. Stability issues were also addressed, in relation to optimisation and reliability. The paper details the physical tracker device developed as a prototype, as well as the proposed advanced control system for optimising the tracking.

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