scholarly journals Elastic Stability of Cosserat Rods and Parallel Continuum Robots

2017 ◽  
Vol 33 (3) ◽  
pp. 718-733 ◽  
Author(s):  
John Till ◽  
D. Caleb Rucker
Keyword(s):  
Elastic Stability ◽  
Continuum Robots ◽  
Cosserat Rods

Stiffness Control of Parallel Continuum Robots

2018 ◽  
Author(s):  
Vincent Aloi ◽  
Caroline Black ◽  
Caleb Rucker
Keyword(s):  
Position Control ◽  
Target Position ◽  
Human Robot Interaction ◽  
Force Measurements ◽  
Modeling Framework ◽  
Continuum Robots ◽  
Integral Control ◽  
Control Approach ◽  
Cosserat Rods ◽  
Stiffness Control

Parallel continuum robots can provide compact, compliant manipulation of tools in robotic surgery and larger-scale human robot interaction. In this paper we address stiffness control of parallel continuum robots using a general nonlinear kinetostatic modeling framework based on Cosserat rods. We use a model formulation that estimates the applied end-effector force and pose using actuator force measurements. An integral control approach then modifies the commanded target position based on the desired stiffness behavior and the estimated force and position. We then use low-level position control of the actuators to achieve the modified target position. Experimental results show that after calibration of a single model parameter, the proposed approach achieves accurate stiffness control in various directions and poses.

Non-Classical Problems in the Theory of Elastic Stability

2001 ◽  
Author(s):  
Isaac Elishakoff ◽  
Yiwei Li ◽  
James H. Starnes, Jr
Keyword(s):  
Elastic Stability

Neural Network Grasping Controller for Continuum Robots

2006 ◽  
Author(s):  
D. Braganza ◽  
D. M. Dawson ◽  
I. D. Walker ◽  
N. Nath
Keyword(s):  
Neural Network ◽  
Continuum Robots

Elastic stability of high dose neutron irradiated spinel

1995 ◽  
Author(s):  
Z Li ◽  
S K Chan ◽  
F A Garner
Keyword(s):  
Elastic Stability ◽  
High Dose

scholarly journals The elastic stability of an annular plate

1924 ◽  
Vol 106 (737) ◽  
pp. 268-284 ◽  
Keyword(s):  
Annular Plate ◽  
Practical Interest ◽  
Middle Surface ◽  
Elastic Stability ◽  
Thin Plates ◽  
Thin Shells ◽  
Stability Equation ◽  
Inner Radius ◽  
Plane Plate ◽  
The Stability

1. Introduction and Summary. —This paper deals with the elastic stability of a circular annular plate under uniform shearing forces applied at its edges. Investigations of the stability of plane plates are altogether simpler than those necessary in the case of curved plates or shells. In the first place, as shown by Mr. R. V. Southwell, two of the three equations of stability relate to a mode of instability that is not of practical interest, and are entirely independent of the third equation which gives the ordinary mode of instability resulting in the familiar bending of the middle surface of the plate. Consequently with a plane plate there is only one equation of stability to be solved, as contrasted with the case of a shell where the three equations are dependent, and must all be solved. In the second place the theory of thin shells can be used with confidence in a plane plate problem, though a more laborious procedure is necessary to deal adequately with a shell. The only stability equation required for the annular plate is therefore deduced without trouble from the theory of thin shells, and its solution presents no difficulty in the case of uniform shearing forces. A numerical discussion is given of the stability of the plate under such forces, the “favourite type of distortion” and the stess that will produce it being obtained for plates with clamped edges in wich the ratio of the outer to the inner radius exceeds 3·2. To some extent to results have been checked by experiment, in which part of the work the viter is indebted to Prof. G. I. Taylor for his valuable help and advice. Distrtion of the type predicted by the theory took place in the two thin plates of rober different ratio of radii, which were used. The disposition of the loci of points which undergo maximum normal displace nt gives some idea of the appearance of the plate after distortion has taken pce. The points have been calculated for a plate in which the ratio of radii 4·18, and the loci are shown on a diagram, which may be compared with a potograph of a distorted plate in which this ratio is 4·3. The ratio of normal dplacements of points of the plate can be seen from contours drawn on the ne diagram. (See pp. 280, 281.)

Parallel Continuum Robots: Modeling, Analysis, and Actuation-Based Force Sensing

2018 ◽  
Vol 34 (1) ◽  
pp. 29-47 ◽  
Author(s):  
Caroline B. Black ◽  
John Till ◽  
D. Caleb Rucker
Keyword(s):  
Force Sensing ◽  
Continuum Robots ◽  
Modeling Analysis
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