The Dynamics of a Gyroscope Supported by a Flexible Circular Plate

1982 ◽  
Vol 49 (3) ◽  
pp. 601-605 ◽  
Author(s):  
J. S. Burdess
Keyword(s):  
Angular Velocity ◽  
Circular Plate ◽  
Angular Displacement ◽  
Performance Characteristics ◽  
Free Motion ◽  
Rigid Rotor ◽  
Modes Of Operation ◽  
Constant Rate ◽  
Flexible Circular Plate

The dynamics of a rigid rotor supported on a flexible circular plate is investigated and it is shown that the arrangement is capable of operating as a tuned free rotor gyroscope. The performance characteristics of the gyroscope are evaluated and the analysis shows that the steady displacment of the rotor may be used to measure either the angular velocity or angular displacement of the supporting casing. For both modes of operation the free motion and the response to a constant rate and a vibratory input is determined.

scholarly journals Stakeholder-Driven Design Evolution of the Leveraged Freedom Chair Developing World Wheelchair

2012 ◽  
Author(s):  
Amos G. Winter ◽  
Mario A. Bollini ◽  
Benjamin M. Judge ◽  
Natasha K. Scolnik ◽  
Harrison F. O’Hanley ◽  
...  
Keyword(s):  
Developing Countries ◽  
Angular Velocity ◽  
East Africa ◽  
Survey Data ◽  
Angular Displacement ◽  
Low Cost ◽  
Center Of Gravity ◽  
Mechanical Advantage ◽  
Design Evolution ◽  
Propulsion Force

The Leveraged Freedom Chair (LFC) is a low-cost, all-terrain, variable mechanical advantage, lever-propelled wheelchair designed for use in developing countries. The user effectively changes gear by shifting his hands along the levers; grasping near the ends increases torque delivered to the drive-train, while grasping near the pivots enables a larger angular displacement with every stroke, which increases angular velocity in the drivetrain and makes the chair go faster. This paper chronicles the design evolution of the LFC through three user trials in East Africa, Guatemala, and India. Feedback from test subjects was used to refine the chair between trials, resulting in a device 9.1 kg (20 lbs) lighter, 8.9 cm (3.5 in) narrower, and with a center of gravity 12.7 cm (5 in) lower than the first iteration. Survey data substantiated increases in performance after successive iterations. Quantitative biomechanical performance data were also measured during the Guatemala and India trials, which showed the LFC to be 76 percent faster and 41 percent more efficient during a common daily commute and able to produce 51 percent higher peak propulsion force compared to conventional, pushrim-propelled wheelchairs.

Thermal stresses in a flexible circular plate of variable rigidity

1981 ◽  
Vol 17 (7) ◽  
pp. 669-672
Author(s):  
Ya. M. Grigorenko ◽  
N. N. Kryukov ◽  
T. G. Akhalaya
Keyword(s):  
Circular Plate ◽  
Thermal Stresses ◽  
Variable Rigidity ◽  
Flexible Circular Plate

Frequencies of a Flexible Circular Plate Attached to the Surface of a Light Elastic Half-Space

1959 ◽  
Vol 26 (1) ◽  
pp. 13-17
Author(s):  
G. N. Bycroft
Keyword(s):  
Free Vibration ◽  
Circular Plate ◽  
Half Space ◽  
Fundamental Frequency ◽  
Elastic Half Space ◽  
Flexible Circular Plate

Abstract The frequencies of free vibration of a thin, flexible, circular plate stuck to the surface of a massless elastic half-space are solved by an application of the Rayleigh-Ritz principle. The approximate fundamental frequency is considered in detail when the plate is clamped, free, or hinged at its periphery. The method of obtaining the higher frequencies, such as those involving nodal diameters, is indicated.

An inertial piezoelectric hybrid actuator with large angular velocity and high resolution

2019 ◽  
Vol 30 (14) ◽  
pp. 2099-2111 ◽  
Author(s):  
Huilu Bao ◽  
Jianming Wen ◽  
Kang Chen ◽  
Jijie Ma ◽  
Dan Lei ◽  
...  
Keyword(s):  
High Resolution ◽  
Angular Velocity ◽  
Natural Frequencies ◽  
Angular Displacement ◽  
High Accuracy ◽  
Laser Vibrometer ◽  
Type B ◽  
First Order ◽  
Offset Distance ◽  
Hybrid Actuator

This article proposes an inertial piezoelectric actuator with hybrid design of asymmetrically clamping structures and a bias unit for the achievement of large angular velocity and high resolution. To investigate the influence of asymmetrical clamp and bias unit on the driving performance, two types of actuators were fabricated and tested. Combined effects from asymmetrical clamp and bias unit contribute to type A, while their subtractive effect is applied to type B. Using a scanning laser vibrometer, experiments were conducted to analyze the characteristics of the angular displacement and corresponding velocity. It is indicated that the measured first-order natural frequencies for above two types are 13.828 and 14.141 Hz, which agrees well with the simulation results of 16.666 and 17.379 Hz, respectively. Besides, compared with the actuators with simple asymmetrical clamping structure or bias unit, this hybrid actuator can obtain an angular velocity 6.87 rad/s at 80 V and 16 Hz and a resolution of 2.80 μrad under a square signal of 20 V and 1 Hz and an offset distance of −22 mm. As a result, the proposed actuators can achieve large angular velocity and high resolution, which is potentially applicable to quick positioning with high accuracy.

Angular velocity and time derivative of angular displacement

1986 ◽  
Vol 54 (11) ◽  
pp. 1029-1031
Author(s):  
J. Schuster ◽  
R. H. Good
Keyword(s):  
Angular Velocity ◽  
Angular Displacement ◽  
Time Derivative

Head Kinematics in Mini-Sled Tests of Foam Padding: Relevance of Linear Responses From Free Motion Headform (FMH) Testing to Head Angular Responses

2003 ◽  
Vol 125 (4) ◽  
pp. 523-532 ◽  
Author(s):  
J. Ivarsson ◽  
D. C. Viano ◽  
P. Lo¨vsund ◽  
Y. Parnaik
Keyword(s):  
Angular Velocity ◽  
Brain Injuries ◽  
Motor Vehicle ◽  
Sagittal Plane ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Free Motion ◽  
Constant Thickness ◽  
Head Impacts ◽  
Hybrid Iii

The revised Federal Motor Vehicle Safety Standard (FMVSS) No. 201 specifies that the safety performance of vehicle upper interiors is determined from the resultant linear acceleration response of a free motion headform (FMH) impacting the interior at 6.7 m/s. This study addresses whether linear output data from the FMH test can be used to select an upper interior padding that decreases the likelihood of rotationally induced brain injuries. Using an experimental setup consisting of a Hybrid III head-neck structure mounted on a mini-sled platform, sagittal plane linear and angular head accelerations were measured in frontal head impacts into foam samples of various stiffness and density with a constant thickness (51 mm) at low (∼5.0 m/s), intermediate (∼7.0 m/s), and high (∼9.6 m/s) impact speeds. Provided that the foam samples did not bottom out, recorded peak values of angular acceleration and change in angular velocity increased approximately linearly with increasing peak resultant linear acceleration and value of the Head Injury Criterion HIC36. The results indicate that the padding that produces the lowest possible peak angular acceleration and peak change in angular velocity without causing high peak forces is the one that produces the lowest possible HIC36 without bottoming out in the FMH test.

scholarly journals Analysing the Kinematic Characteristics of Bennett Mechanisms and Its Networks for Usage in Forming Deployable Structures

Mechanika ◽  
2019 ◽  
Vol 25 (4) ◽  
pp. 269-275
Author(s):  
Tony punnoose Valayil ◽  
Selladurai Velappan ◽  
Prakash Lakshmana Pandian
Keyword(s):  
Angular Velocity ◽  
Angular Displacement ◽  
Twist Angle ◽  
Angular Acceleration ◽  
Singularity Analysis ◽  
Equal Length ◽  
Simulation Environment ◽  
Deployable Structures ◽  
Saddle Surface ◽  
Saddle Shape

Two types of bennett mechanism are      encountered in most of the related literatures. This research aims at finding the best type of bennett mechanism out of the two and then using it for suitable application. One type of bennett mechanism is known as equilateral bennett mechanism, which has all the four kinematic links of equal lengths. Next type is a bennett mechanism having their opposite links of equal length. Using the two types of bennett mechanism, two different networks are created. Their working range, minimum foldability and maximum foldability of the networks were identified using MATLAB-SimMechanics toolbox. Thus, the network having better foldability was identified, so that it can be used for making foldable tent application, which is a deployable structure. The results from the analysis prove that equilateral bennett mechanism had better foldability than its counterpart. Then on analyzing the shapes of the networks, it was found that the networks had a saddle shape. The obtained saddle surface provided certain results like, when the twist angles of the bennett links were varied, saddle surfaces with more steepness are obtained. The influence of twist angle on angular displacement, angular velocity, and angular acceleration of the mechanism were also analyzed. Singularity analysis of these networks was done in Matlab-SimMechanics simulation environment. Coupler curves for both types of bennett mechanism were plotted to identify the trajectory of the output links

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