Design of Sub-Centimetre Underactuated Compliant Grippers

Author(s):  
Eric Boudreault ◽  
Cle´ment M. Gosselin

This paper proposes a methodology for the design of a sub-centimetre underactuated compliant gripper. The gripper is optimized in order to maintain a proper force distribution on the phalanges and to avoid the deformation of soft objects. In order to keep the design simple and to limit the complexity of the control, each finger is based on a planar five-bar linkage. The five-bar mechanism is a well known and efficient underactuated mechanism. In this work, the revolute joints are replaced by flexible hinges in order to allow the miniaturization of the mechanism and make it easy to clean and sterilize. The behaviour of the prototypes built shows the effectiveness of the proposed method.

2013 ◽  
Vol 4 (1) ◽  
pp. 1-12
Author(s):  
G. Lámer

Abstract The paper is an overview of issues related to the space creation of a building, possibilities of developing frame structure and connections of force distribution in the construction. In plane the force distribution can be compression, bending and tension. In space “enclosing” a geometric solid means space creation. In space as it is to be expected, the force distribution must be compression, bending and tension in two different directions at the same time. This can be really variant but in the case of surface or surface-like constructions generated by translations (and/or rotations) on one hand, there are some other surfaces, which cannot be generated by translations (and/or rotations), on the other hand, the dimension of the inside “forces” is not two but three (independent components of a two-by-two tensor either in the case of compression tension, or in the case of bending). By this, force distribution is more complicated in space than in plane.


1986 ◽  
Vol 14 (3) ◽  
pp. 139-159 ◽  
Author(s):  
A. G. Veith

Abstract A system, called the “Driving Severity Monitor” (DSM), has been developed for characterizing tire force distribution as related to treadwear in either normal tire use or in tire fleet testing in a convoy. The system consists of an accelerometer for monitoring lateral accelerations, a wheel revolution counter, and a module for signal processing and read-out. The output of the DSM is reduced to a single index, the Driving Severity Number (DSN), which characterizes a vehicle journey. The DSN is equal to the sum of squares of lateral acceleration measured once per tire revolution during a trip, divided by the number of wheel revolutions. The DSN had a high degree of correlation (R ≧ 0.95) with treadwear in two wear programs when pavement abrasiveness was held constant. This supports the concept that the three basic treadwear components: tire force distribution, pavement abrasiveness, and ambient temperature, can be separated for better understanding of tire treadwear.


2020 ◽  
Vol 20 (2) ◽  
pp. 700-706 ◽  
Author(s):  
Xuguang Sun ◽  
Jun Zhou ◽  
Ning Xue ◽  
Keshi Zhang ◽  
Shuaikang Zheng ◽  
...  

2013 ◽  
Vol 146 (6) ◽  
pp. 1381-1386 ◽  
Author(s):  
Philipp Aigner ◽  
Farsad Eskandary ◽  
Thomas Schlöglhofer ◽  
Roman Gottardi ◽  
Klaus Aumayr ◽  
...  

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Eman M. Ibraheem ◽  
Hisham S. ElGabry

Abstract Background This study aimed to evaluate the effect of mandibular complete dentures relining using soft relining material on the distribution of various occlusal forces using T-Scan system. Fifty completely edentulous patients having their conventional complete dentures earlier fabricated and utilized were selected for this study. Patients were controlled diabetics, characterized by having their residual alveolar ridges moderately developed and lined with firm mucoperiosteum. Mandibular complete dentures were relined with soft denture liner and T-Scan device was used for occlusal force distribution measurement prior to denture relining and three months thereafter the relinning procedure. Results Comparison between occlusal forces percentages before and after denture relining revealed that occlusal forces percentages was significantly lower after denture relining in anterior area, significantly higher after denture relining in right posterior area, where it was insignificantly higher after relining in left posterior area. Conclusions Our findings revealed that the use of soft denture liner for mandibular complete denture relining significantly improved the occlusal load distribution. Clinical trial registration Trial registration NCT, NCT04701970. Registered 23/11/2020—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04701970


Biomechanics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 102-117
Author(s):  
Nasser Rezzoug ◽  
Vincent Hernandez ◽  
Philippe Gorce

A force capacity evaluation for a given posture may provide better understanding of human motor abilities for applications in sport sciences, rehabilitation and ergonomics. From data on posture and maximum isometric joint torques, the upper-limb force feasible set of the hand was predicted by four models called force ellipsoid, scaled force ellipsoid, force polytope and scaled force polytope, which were compared with a measured force polytope. The volume, shape and force prediction errors were assessed. The scaled ellipsoid underestimated the maximal mean force, and the scaled polytope overestimated it. The scaled force ellipsoid underestimated the volume of the measured force distribution, whereas that of the scaled polytope was not significantly different from the measured distribution but exhibited larger variability. All the models characterized well the elongated shape of the measured force distribution. The angles between the main axes of the modelled ellipsoids and polytopes and that of the measured polytope were compared. The values ranged from 7.3° to 14.3°. Over the entire surface of the force ellipsoid, 39.7% of the points had prediction errors less than 50 N; 33.6% had errors between 50 and 100 N; and 26.8% had errors greater than 100N. For the force polytope, the percentages were 56.2%, 28.3% and 15.4%, respectively.


Author(s):  
Yuan-Ting Lin ◽  
Chyuan-Yow Tseng ◽  
Jao-Hwa Kuang ◽  
Yeong-Maw Hwang

The combined brake system (CBS) is a mechanism that links the front and rear brakes for scooters. For two-wheeled scooters, a CBS with appropriate braking force distribution can reduce the risk of crashing accidents due to insufficient driving proficiency. The design of the braking force distribution for a CBS is challenging to the designer because it has to fulfill many requirements such as braking performance, ride comfort, reliability, and low costs. This paper proposes a systematic method to optimize the parameters of CBS. The evaluation indexes for the design are first discussed. The steps to determine the critical parameter to meet the indexes and a method to predict braking performance are developed. Finally, driving tests are carried out to verify the effectiveness of the proposed method. Experimental results showed that the deceleration of the tested scooter equipped with the designed CBS achieves an average mean fully developed deceleration (MFDD) of 5.246 m/s2, higher than the homologation requirement. Furthermore, the proposed method’s prediction of braking performance is in good agreement with the test results, with errors <1%.


Author(s):  
Tony Lin-Wei Chen ◽  
Wing-Kai Lam ◽  
Duo Wai-Chi Wong ◽  
Ming Zhang

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