1,054 research outputs found
Trapeziometacarpal Joint: A Mechanical Explanation of Total Prosthesis Failures
Total prosthesis, which preserves strength and respects trapeziometacarpal (TMC) joint range of motion, is a surgical option considered for the TMC joint replacement. With the usual ball-and-socket design, patients obtain faster pain relief, stronger grip function, and shorter convalescence than with trapeziectomy. However, prostheses currently used have led to various early complications, especially in active and young patients. Revisions are most often due to the loosening of the trapezium cup and of the metacarpal stem and to the luxation of the first metacarpal bone. The short lifespan of these devices suggests the difficulty of designing a prosthesis that respects the complex anatomy and motions of the TMC joint. Early implant failure may reflect the fact that the current devices do not exactly replicate the true kinematics. The aim of this chapter will be to shed light mechanical explanations for TMC prosthesis failures in regard to the complex kinematics of the joint
Obstacle detection algorithm of low computational cost for Guanay II AUV
Obstacle detection is one of the most important
stages in the obstacle avoidance system. This work is focused
to explain the operation of a designed and implemented for
the overall detection of objects with low computational cost
strategy. This strategy of low computational cost is based on
performing a spatial segmentation of the information
obtained by the SONAR and determine the minimum
distance between the SONAR (AUV) and the obstacle.Postprint (published version
The predictive functional control and the management of constraints in GUANAY II autonomous underwater vehicle actuators
Autonomous underwater vehicle control has been a topic of research in the last decades. The challenges addressed vary depending on each research group's interests. In this paper, we focus on the predictive functional control (PFC), which is a control strategy that is easy to understand, install, tune, and optimize. PFC is being developed and applied in industrial applications, such as distillation, reactors, and furnaces. This paper presents the rst application of the PFC in autonomous underwater vehicles, as well as the simulation results of PFC, fuzzy, and gain scheduling controllers. Through simulations and navigation tests at sea, which successfully validate the performance of PFC strategy in motion control of autonomous underwater vehicles, PFC performance is compared with other control techniques such as fuzzy and gain scheduling control. The experimental tests presented here offer effective results concerning control objectives in high and intermediate levels of control. In high-level point, stabilization and path following scenarios are proven. In the intermediate levels, the results show that position and speed behaviors are improved using the PFC controller, which offers the smoothest behavior. The simulation depicting predictive functional control was the most effective regarding constraints management and control rate change in the Guanay II underwater vehicle actuator. The industry has not embraced the development of control theories for industrial systems because of the high investment in experts required to implement each technique successfully. However, this paper on the functional predictive control strategy evidences its easy implementation in several applications, making it a viable option for the industry given the short time needed to learn, implement, and operate, decreasing impact on the business and increasing immediacy.Peer ReviewedPostprint (author's final draft
To All Members of the Young Communist League
Political flyer discussing updates from the Young Communist International. Student Publications: The Campus Newspaper Collectio
April 12 Strike In Danger
Flyer for political rally on April 12, 1935. Student Publications: The Campus Newspaper Collectio
Boycott Robinson Meeting
Flyer calling for boycott of political rally on November 8, 1935.Student Publications: The Campus Newspaper Collectio
Design of obstacle detection and avoidance system for GUANAY II AUV
Postprint (published version
All Out to Jasper Oval at 12 Noon To-Day!
Flyer calling for boycott of political rally on November 8, 1935. Student Publications: The Campus Newspaper Collectio
Introductory notes for the Acta IMEKO Special Issue on the “19th Symposium on Measurement of Electrical Quantities” and the “17th Workshop on ADC/DAC Modelling and Testing”
Postprint (published version
Range-only benthic Rover localization off the central California coast
Nowadays, the use of autonomous vehicles for
ocean research has increased, since these vehicles have a better
cost/performance ratio than crewed vessels or oceanographic
ships. For example, autonomous surface vehicles can be used to
localize underwater targets. This paper describes a mission to find
a crawling robot - Benthic Rover - on the abyssal plain in the north
eastern Pacific, using single-beacon localization from onboard a
Wave Glider autonomous surface vehicle. While the Wave Glider
is moving around the surface in the target zone, it takes ranges
between the target and itself using acoustic modems. With these
ranges it can compute the target location, as a Long Baseline
(LBL) system. The benefit of this approach is the reduction of cost
and complexity relative to deployment of a traditional shipboard
LBL system. Additionally, this is a mobile system, and can cover
long distances, and can geolocate multiple targets over a large
area.Postprint (author's final draft
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