Development of a differential cable drive mechanism for acquiring tracking and pointing application

2014 ◽  
Vol 229 (17) ◽  
pp. 3191-3200 ◽  
Author(s):  
Yafei Lu ◽  
Hongbo Liao ◽  
Mo Hei ◽  
Hua Liu ◽  
Dapeng Fan
Keyword(s):  
Mechanical Design ◽  
Operating Conditions ◽  
Lagrange Equations ◽  
Differential Relation ◽  
Drive Mechanism ◽  
Kinetic Coupling ◽  
Cable Drive ◽  
Kinetic Principle ◽  
Decoupled Control ◽  
Structure Configuration

A brief overview of previously built acquiring tracking and pointing devices reveals a trend toward smaller, more agile systems. A differential cable drive mechanism is developed to realize large look angle, high precise and compact structures. The mechanical design, including structure configuration, transmission system, and feathers, is introduced. The kinetic principle is studied and the differential relation between the motors orientations and gimbals pointing positions is investigated. Dynamics of the differential cable drive mechanism is studied based on the Lagrange equations, and the dynamics coupling and kinetic coupling is analyzed. The differential cable drive mechanism is machined and assembled. Experimental setup is built, and the frequency response in different operating conditions is investigated and the transmission performance is tested. Studies and analysis in this paper could provide a basis for further decoupled control of the differential cable drive mechanism.

Proving the Labeled Interval Calculus for Inferences on Catalogs

1990 ◽  
Author(s):  
Walid Habib ◽  
Allen C. Ward
Keyword(s):  
Mechanical Design ◽  
Formal System ◽  
Constraint Propagation ◽  
Operating Conditions ◽  
Manufacturing Processes ◽  
Entire System ◽  
High Level Language ◽  
Design Problems ◽  
High Level ◽  
Interval Constraint

Abstract The “labeled interval calculus” is a formal system that performs quantitative inferences about sets of artifacts under sets of operating conditions. It refines and extends the idea of interval constraint propagation, and has been used as the basis of a program called a “mechanical design compiler,” which provides the user with a “high level language” in which design problems for systems to be built of cataloged components can be quickly and easily formulated. The compiler then selects optimal combinations of catalog numbers. Previous work has tested the calculus empirically, but only parts of the calculus have been proven mathematically. This paper presents a new version of the calculus and shows how to extend the earlier proofs to prove the entire system. It formalizes the effects of toleranced manufacturing processes through the concept of a “selectable subset” of the artifacts under consideration. It demonstrates the utility of distinguishing between statements which are true for all artifacts under consideration, and statements which are merely true for some artifact in each selectable subset.

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.

In Pursuit of a Design Mathematics: Generalizing the Labeled Interval Calculus

1991 ◽  
Author(s):  
Walid Habib ◽  
Allen C. Ward
Keyword(s):  
Mechanical Design ◽  
Operating Conditions ◽  
Algebraic Equations

Abstract The Labeled Interval Calculus (LIC) is a formalism for reasoning about sets of design possibilities. Examples include toleranced objects, abstract descriptions involving many possible instantiations, and varying operating conditions. It has been successful in a “mechanical design compiler”, which accepts schematics and specifications and returns catalog numbers for optimal implementations. The LIC at present operates on monotonic algebraic equations and intervals of real values, but it now appears possible to generalize it to address arbitrary types of mathematical sets and relationships. The resulting family of formalisms is expected to be useful in design by feature and other design programs.

Substantiation of amplitude-frequency characteristics and design parameters of vibration exciter in volume oscillation separator

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
I Palamarchuk ◽  
◽  
V Vasyliv ◽  
V Sarana ◽  
M Mushtruk ◽  
...  
Keyword(s):  
Translational Motion ◽  
Operating Conditions ◽  
Design Parameters ◽  
Vibration Velocity ◽  
Vibration Exciter ◽  
Lagrange Equations ◽  
Bulk Materials ◽  
Vibrating Screen ◽  
Working Bodies ◽  
Oscillating Motion

The main effects of the developed design for vibratory separator: the increased driving force in the process of bulk material separation in this work, achieved by providing the working cylindrical-conical container with vibrational motion; improving the conditions for the passage of product particles through openings, achieved by providing the sieve surface with volume oscillations; reduction of energy consumption and improvement of operating conditions for support nodes during the operation of the designed vibrating screen, achieved due to the installation of additional elastic elements between the separator body and bearing assemblies of the vertical drive shaft in vibration exciter. Providing the working bodies of the designed vibrating screen with volume oscillating motion allows increasing the performance and quality of the separation process of solid bulk materials. To determine the rational parameters for vibration screening process, the equations of motion of working bodies as a conical sieve surface were obtained using the method of the Lagrange equations of the second order. When applying solutions of the Cauchy problem for linear nonhomogeneous differential equations, the solution of the latter was obtained. The obtained dependences of oscillation amplitudes, vibration velocity and vibration acceleration, and the intensity of oscillating motion allowed us to perform a mathematical analysis for power and energy parameters of vibration drive in the developed separator. The inclined placement of the conical sieve surface allows for spatial gyration or circular translational motion, which makes it possible to realize the advantages of volumetric separation of bulk materials. The results of the conducted analytical study made it possible to substantiate the optimal inclination angle for working sieve surface. Based on our analysis, the design parameters of vibration exciter were substantiated and clarified, and the design of this technical system was demonstrated.

Mechanical Design and Testing of a 2.5 MW sCO2 Compressor Loop

2021 ◽  
Author(s):  
Stefan D. Cich ◽  
J. Jeffrey Moore ◽  
Chris Kulhanek ◽  
Meera Day Towler ◽  
Jason Mortzheim
Keyword(s):  
High Efficiency ◽  
Mechanical Design ◽  
Guide Vane ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Design Changes ◽  
Wide Range ◽  
Inlet Conditions ◽  
Design And Testing

Abstract An enabling technology for a successful deployment of the sCO2 close-loop recompression Brayton cycle is the development of a compressor that can maintain high efficiency for a wide range of inlet conditions due to large variation in properties of CO2 operating near its dome. One solution is to develop an internal actuated variable Inlet Guide Vane (IGV) system that can maintain high efficiency in the main and re-compressor with varying inlet temperature. A compressor for this system has recently been manufactured and tested at various operating conditions to determine its compression efficiency. This compressor was developed with funding from the US DOE Apollo program and industry partners. This paper will focus on the design and testing of the main compressor operating near the CO2 dome. It will look at design challenges that went into some of the decisions for rotor and case construction and how that can affect the mechanical and aerodynamic performance of the compressor. This paper will also go into results from testing at the various operating conditions and how the change in density of CO2 affected rotordynamics and overall performance of the machine. Results will be compared to expected performance and how design changes were implanted to properly counter challenges during testing.

Design, Test and Analysis of a High-Pressure-Ratio Transonic Fan

2003 ◽  
Author(s):  
W. John Calvert ◽  
Paul R. Emmerson ◽  
Jon M. Moore
Keyword(s):  
High Performance ◽  
Mechanical Design ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Pressure Transducers ◽  
Technology Acquisition ◽  
Laser Anemometry ◽  
High Pressure Ratio ◽  
Response Pressure ◽  
Stage Matching

Aircraft gas turbine engines require compression systems with high performance and low weight and cost. There is therefore a continuing drive to increase compressor stage pressure ratios, particularly for military fans. To meet this need, a technology acquisition programme has been carried out by QinetiQ and Rolls-Royce. Firstly, the stage matching issues for an advanced two-stage military fan were investigated, including the effects of employing variable inlet guide vanes. From this, the requirements for the first stage together with key operating conditions for the blading were defined. The blade profiles were then designed to satisfy the range of aerodynamic conditions using a quasi-3D calculation system. A satisfactory compromise between the aerodynamic and mechanical design requirements was reached in which a blisk construction was employed for the rotor, machined from a single piece of titanium. The new stage was manufactured and tested successfully, and it achieved its target flow, pressure ratio and efficiency on the first build. Detailed measurements of the internal flows using laser anemometry and high response pressure transducers were taken. Finally, these data have been analysed and used to calibrate current 3D multi-row CFD methods.

Tensile Characterization of Narrow Gap Bimetallic Weld Ferritic-Austenitic Steel With a New Measurement System for Tensile Testing

2016 ◽  
Author(s):  
O. Ancelet ◽  
S. Chapuliot
Keyword(s):  
Measurement System ◽  
Tensile Testing ◽  
Mechanical Design ◽  
Postweld Heat Treatment ◽  
Operating Conditions ◽  
Curvature Radius ◽  
Local Behavior ◽  
Stainless Steel 316L ◽  
Minimum Diameter ◽  
Examination Methods

Ferritic steel 2 ¼ Cr is a candidate material for future pressure component in nuclear fields. In order to validate this choice, it is necessary, firstly to verify that it is able to withstand the planned environmental and operating conditions, and secondly to check if it is covered by the existing design codes, concerning its procurement, fabrication, welding, examination methods and mechanical design rules. A large R&D program on 2 ¼ Cr steel has been undertaken at CEA and Areva in order to characterize the behavior of this material and of its welded junctions. In this frame, a new measurement system for tensile testing was developed in the LISN laboratory of the CEA (French atomic commission), in order to characterize the local behavior of the material during a whole tensile testing. Indeed, with the conventional measurement system (typically an extensometer), the local behavior of the material can only be determinate during the stable step of the testing. So, usually the behavior of the material during the necking step of the step is unknown. This new measurement is based on the use of some laser micrometers which allow measuring the minimum diameter of the specimen and the curvature radius during the necking phase with a great precision. Thanks to the Bridgman formula, we can evaluate the local behavior of the material until the failure of the specimen. This new system was used to characterize the tensile propriety of a bimetallic welded junction of 2 ¼ Cr steel and austenitic stainless steel 316L(N) realized with inconel filler metal. These works lead to propose a tensile curve for each materials of the welded junction at room temperature and the effect of postweld heat treatment.

Study on Working Performances and Factor Combinations of ASU

2013 ◽  
Vol 455 ◽  
pp. 286-291
Author(s):  
Chang Jun Zhou ◽  
Wei Wang ◽  
Yang Ge ◽  
Yue Ma
Keyword(s):  
Angular Velocity ◽  
Orthogonal Experiment ◽  
Work Conditions ◽  
Operating Conditions ◽  
Lagrange Equations ◽  
Work System ◽  
Shock Resistance

Focus on the performances of ASU, this paper utilized Lagrange equations to build the modeling of ASU and comprehensively analyze the work performances including shock resistance, synchronization and stability by use of orthogonal experiment methods under nine different operating conditions of coupling horizontal, rolling and pitching movements. From simulations of the work system in the velocity of 5~15(m/s), rolling angular velocity of 0~12 (rad/s), pitching angular velocity of 0~6 (rad/s), the results can be obtained under combined 3-factor and 3-level work conditions: the optimized combination is the speed in range of 10~15 (m/s), rolling angular velocity of 4~8 (deg/s) and pitching angular velocity of 4~6 (deg/s) and whole work performances fulfill the designed requirements.

Plasto-Elastohydrodynamic Lubrication in Point Contacts for Surfaces With Three-Dimensional Sinusoidal Waviness and Real Machined Roughness

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Tao He ◽  
Ning Ren ◽  
Dong Zhu ◽  
Jiaxu Wang
Keyword(s):  
Plastic Deformation ◽  
Rough Surface ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Operating Conditions ◽  
Von Mises Stress ◽  
Asperity Contacts ◽  
Lubrication Characteristics ◽  
Von Mises

Efficiency and durability are among the top concerns in mechanical design to minimize environmental impact and conserve natural resources while fulfilling performance requirements. Today mechanical systems are more compact, lightweight, and transmit more power than ever before, which imposes great challenges to designers. Under the circumstances, some simplified analyses may no longer be satisfactory, and in-depth studies on mixed lubrication characteristics, taking into account the effects of 3D surface roughness and possible plastic deformation, are certainly needed. In this paper, the recently developed plasto-elastohydrodynamic lubrication (PEHL) model is employed, and numerous cases with both sinusoidal waviness and real machined roughness are analyzed. It is observed that plastic deformation may occur due to localized high pressure peaks caused by the rough surface asperity contacts, even though the external load is still considerably below the critical load determined at the onset of plastic deformation in the corresponding smooth surface contact. It is also found, based on a series of cases analyzed, that the roughness height, wavelength, material hardening property, and operating conditions may all have significant influences on the PEHL performance, subsurface von Mises stress field, residual stresses, and plastic strains. Generally, the presence of plastic deformation may significantly reduce some of the pressure spikes and peak values of subsurface stresses and make the load support more evenly distributed among all the rough surface asperities in contact.

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