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Optimum Balancing of the Four-Bar Linkage Using Fully Cartesian Coordinates

2019 , Acevedo, Mario , Orvañanos-Guerrero, María T. , Velázquez, Ramiro , Haro-Sandoval, Eduardo

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Gradient Descent-Based Optimization Method of a Four-Bar Mechanism Using Fully Cartesian Coordinates

2019 , Orvañanos-Guerrero, María T. , Sánchez-Gómez, Claudia , Mariano Rivera , Acevedo, Mario , Velázquez, Ramiro

Machine vibrations often occur due to dynamic unbalance inducing wear, fatigue, and noise that limit the potential of many machines. Dynamic balancing is a main concern in mechanism and machine theory as it allows designers to limit the transmission of vibrations to the frames and base of machines. This work introduces a novel method for representing a four-bar mechanism with the use of Fully Cartesian coordinates and a simple definition of the shaking force (ShF) and the shaking moment (ShM) equations. A simplified version of Projected Gradient Descent is used to minimize the ShF and ShM functions with the aim of balancing the system. The multi-objective optimization problem was solved using a linear combination of the objectives. A comprehensive analysis of the partial derivatives, volumes, and relations between area and thickness of the counterweights is used to define whether the allowed optimization boundaries should be changed in case the mechanical conditions of the mechanism permit it. A comparison between Pareto fronts is used to determine the impact that each counterweight has on the mechanism’s balancing. In this way, it is possible to determine which counterweights can be eliminated according to the importance of the static balance (ShF), dynamic balance (ShM), or both. The results of this methodology when using three counterweights reduces the ShF and ShM by 99.70% and 28.69%, respectively when importance is given to the static balancing and by 83.99% and 8.47%, respectively, when importance is focused on dynamic balancing. Even when further reducing the number of counterweights, the ShF and ShM can be decreased satisfactorily.

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Heidegger and the simile of the cave. The assumptions of its interpretation

2020 , Domínguez-Soberanes, Julieta , Sánchez-Gómez, Claudia , Orvañanos-Guerrero, María T.

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Force Balancing of the 2RRR Planar Parallel Manipulator via Center of Mass Acceleration Control Using Fully Cartesian Coordinates

2020 , Acevedo, Mario , Orvañanos-Guerrero, María T.

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SPICE compact model of controlling electrons of spin qubits using FinFET

2023 , Elias A. Pérez-Rodríguez , Orvañanos-Guerrero, María T. , Tetsufumi Tanamoto

Abstract Semiconductor qubits have garnered attention in the field of device physics. Owing to the limited coherence of electrons and holes, smaller and more compact qubits are desirable. This requirement is aligned with the miniaturization of conventional transistors. In this study, we consider a compact spin qubit based on the FinFET (Fin Field-Effect Transistor) by using the SPICE (Simulation Program with Integrated Circuit Emphasis) simulator. The qubits are represented by the quantum dots (QDs) between the Fin structure. In order to setup the qubit, we have to control the number of electrons through the FinFET. Here, we consider the circuit model of our system by treating the transport properties of the QD and the FinFET as single-electron phenomena. We provide the SPICE simulation results and show the single-electron current as the functions of the FinFET parameters such as the channel length and width including the operation temperature.

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A forgotten and unforgettable story. Carranza, Constitution and Catholic Church in Mexico (1914-1919)

2022 , Velázquez, Ramiro , Acevedo, Mario , Sánchez-Gómez, Claudia , Orvañanos-Guerrero, María T.

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An Alternative Method for Shaking Force Balancing of the 3RRR PPM through Acceleration Control of the Center of Mass

2020 , Acevedo, Mario , Orvañanos-Guerrero, María T. , Velázquez, Ramiro , Vigen Arakelian

The problem of shaking force balancing of robotic manipulators, which allows the elimination or substantial reduction of the variable force transmitted to the fixed frame, has been traditionally solved by optimal mass redistribution of the moving links. The resulting configurations have been achieved by adding counterweights, by adding auxiliary structures or, by modifying the form of the links from the early design phase. This leads to an increase in the mass of the elements of the mechanism, which in turn leads to an increment of the torque transmitted to the base (the shaking moment) and of the driving torque. Thus, a balancing method that avoids the increment in mass is very desirable. In this article, the reduction of the shaking force of robotic manipulators is proposed by the optimal trajectory planning of the common center of mass of the system, which is carried out by “bang-bang” profile. This allows a considerable reduction in shaking forces without requiring counterweights, additional structures, or changes in form. The method, already presented in the literature, is resumed in this case using a direct and easy to automate modeling technique based on fully Cartesian coordinates. This permits to express the common center of mass, the shaking force, and the shaking moment of the manipulator as simple analytic expressions. The suggested modeling procedure and balancing technique are illustrated through the balancing of the 3RRR planar parallel manipulator (PPM). Results from computer simulations are reported.

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Design and Characterization of a Miniature Bio-Inspired Mobile Robot

2021 , Velázquez, Ramiro , Claudia L. Garzon-Castro , Acevedo, Mario , Orvañanos-Guerrero, María T. , Amir A. Ghavifekr

This paper presents the design, implementation, and characterization of a miniature crab-like walking robot. The first prototype developed is a four-legged servomotor actuated machine that exhibits compact dimensions, low mass, and is capable of overcoming obstacles and moving on irregular terrain and confined spaces. Its bio-inspired design ensures the compliance of its locomotion mechanism even in the presence of external disturbances. The mechanical design, the implementation of the prototype, and its electronic control approach are first discussed. Next, a kinematic analysis characterizing its motion is presented. The aim of this device is to serve as an educational supporting platform for understanding robot kinematics and legged locomotion.

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Efficient Balancing Optimization of a Simplified Slider-Crank Mechanism

2020 , Orvañanos-Guerrero, María T. , Acevedo, Mario , Nicola Ivan Giannoccaro , Paolo Visconti , Sánchez-Gómez, Claudia , Velázquez, Ramiro

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Analysis of Meat Color Change using Computer Vision

2020 , Gustavo Meza , Sánchez-Gómez, Claudia , Orvañanos-Guerrero, María T. , Domínguez-Soberanes, Julieta