Asymmetric Velocity Profile with Fixed Motion Time for Motion Control

2012 ◽  
Vol 6 (1) ◽  
pp. 593-598
Author(s):  
Teng Li ◽  
Yanjie Liu ◽  
Lining Sun
Keyword(s):  
Velocity Profile ◽  
Motion Control ◽  
Motion Time

Variable-Geometry Motion Control of an Aircraft Door

1999 ◽  
Vol 121 (2) ◽  
pp. 195-199
Author(s):  
L. Beiner
Keyword(s):  
Velocity Profile ◽  
Boundary Value Problem ◽  
Constrained Optimization ◽  
Motion Control ◽  
Initial Position ◽  
Variable Geometry ◽  
Final Position ◽  
Point Boundary ◽  
Lower Edge ◽  
Bevel Gears

The paper deals with the motion control of an aircraft door hinged at its lower edge. The door opens under the influence of weight, restrained by cross-mounted air springs and dampers. The goal is to mechanically control the motion so as to bring the door in a specified time from rest at a specified initial position to rest at a specified final position, while minimizing the peak force in the dampers. It is shown that such a velocity profile requires to engage the dampers at an optimized position and simultaneously start to modulate the spring moment so that it equals the weight moment at the final position. A variable-geometry solution is proposed consisting of a mechanical feedback in which the door rotation drives an elongation of the spring levers via bevel gears and screw leads. The associated double two point boundary value problem is solved by casting it into a constrained optimization form, yielding the required damper engagement position, the amount of spring lever extension and the damper lever length. The approach is illustrated by a design example.

Optimal Point-to-Point Motion Control of Robots With Redundant Degrees of Freedom

1986 ◽  
Vol 108 (2) ◽  
pp. 120-126 ◽  
Author(s):  
R. G. Fenton ◽  
B. Benhabib ◽  
A. A. Goldenberg
Keyword(s):  
Motion Control ◽  
Degrees Of Freedom ◽  
Generalized Inverse ◽  
Optimization Procedure ◽  
Merit Function ◽  
Robot Arm ◽  
Optimal Point ◽  
Motion Time ◽  
Point Motion ◽  
Point To Point

Control of a kinematically redundant robot arm requires an optimization procedure to determine the motion of the end effector. The criterion for optimization can be minimum motion time, minimum joint displacement increments or a combined merit function specified according to the requirements of the user. Three different methods may be used to perform the computations and obtain the joint coordinate increments for the point-to-point motion control of the robot. The methods are the “direct,” the “pseudoinverse” and the “generalized inverse” methods. These methods are described in detail in this paper, and results obtained with the three methods are compared on the basis of performing simulated tasks. It is concluded that the generalized inverse method is the most suitable, general method for point-to-point control of robots with more than six degrees-of-freedom.

scholarly journals Trolley Motion Control Based on S-shaped Velocity Profile for Quay Crane Cargo Oscillation Comparison

2017 ◽  
Vol 9 (3) ◽  
pp. 283-288
Author(s):  
Tomas Eglynas ◽  
Marijonas Bogdevičius ◽  
Arūnas Andziulis ◽  
Mindaugas Jusis
Keyword(s):  
Velocity Profile ◽  
Motion Control ◽  
Velocity Profiles ◽  
Minimum Time ◽  
Scaled Model ◽  
Crane Control ◽  
Quay Cranes ◽  
Profiling Techniques

Quay cranes are used to move containers from ship to store in minimum time so that the load reaches its destination without payload oscillation. During the operations, containers are suspended by cables and it’s free to swing by motion. This paper investigates the two different velocity profiling techniques used for quay crane control and cargo stabilization. A laboratory scaled model of a crane is used to experimentally research, where the trolley acceleration is used as input, for suppressing the container sway. The residual cargo oscillation problems using different velocity profiles are discussed.

Investigation of the influence of the flow structure on the accuracy of flow measurement before a hydrometric structure in an open channel

2020 ◽  
pp. 41-44
Author(s):  
Anatoly Kusher
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Water Flow ◽  
Flow Measurement ◽  
Water Discharge ◽  
Critical Depth ◽  
Flow Measurements ◽  
Study Results ◽  
Flow Velocity Profile ◽  
Upstream Flow

The reliability of water flow measurement in irrigational canals depends on the measurement method and design features of the flow-measuring structure and the upstream flow velocity profile. The flow velocity profile is a function of the channel geometry and wall roughness. The article presents the study results of the influence of the upstream flow velocity profile on the discharge measurement accuracy. For this, the physical and numerical modeling of two structures was carried out: a critical depth flume and a hydrometric overfall in a rectangular channel. According to the data of numerical simulation of the critical depth flume with a uniform and parabolic (1/7) velocity profile in the upstream channel, the values of water discharge differ very little from the experimental values in the laboratory model with a similar geometry (δ < 2 %). In contrast to the critical depth flume, a change in the velocity profile only due to an increase in the height of the bottom roughness by 3 mm causes a decrease of the overfall discharge coefficient by 4…5 %. According to the results of the numerical and physical modeling, it was found that an increase of backwater by hydrometric structure reduces the influence of the upstream flow velocity profile and increases the reliability of water flow measurements.

Science Regained [1962]

2018 ◽  
Author(s):  
Pierre Aubenque
Keyword(s):  
Human Activity ◽  
Human Cognition ◽  
Human Thought ◽  
Motion Time ◽  
First Philosophy

Pierre Aubenque’s “Science Regained” (1962; translated by Clayton Shoppa) was originally published as the concluding chapter of Le Problème de l’Être chez Aristote, one of the most important and original books on Aristotle’s Metaphysics. In this essay, Aubenque contends that the impasses which beset the project of first philosophy paradoxically become its greatest accomplishments. Although science stabilizes motion and thereby introduces necessity into human cognition, human thought always occurs amidst an inescapable movement of change and contingency. Aristotle’s ontology, as a discourse that strives to achieve being in its unity, succeeds by means of the failure of the structure of its own approach: the search of philosophy – dialectic – becomes the philosophy of the search. Aubenque traces this same structure of scission, mediation, and recovery across Aristotelian discussions of theology, motion, time, imitation, and human activity.

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