scholarly journals Design, Construction and Validation of a Proof of Concept Flexible–Rigid Mechanism Emulating Human Leg Behavior

2021 ◽  
Vol 11 (19) ◽  
pp. 9351
Author(s):  
Erik Jung ◽  
Victoria Ly ◽  
Christopher Cheney ◽  
Nicholas Cessna ◽  
Mai Linh Ngo ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Limited Range ◽  
Assistive Device ◽  
Proof Of Concept ◽  
Simulation Environment ◽  
Revolute Joints ◽  
Kinematic Behavior ◽  
Physical Prototype ◽  
Human Joints ◽  
Design Construction

In most robotics simulations, human joints (e.g., hips and knees) are assumed to be revolute joints with limited range rotations. However, this approach neglects the internal flexibility of the joint, which could present a significant drawback in some applications. We propose a tensegrity-inspired robotic manipulator that can replicate the kinematic behavior of the human leg. The design of the hip and knee resembles the musculoskeletal connections within the human body. Our implementation represents muscles, tendons and ligament connections as cables, and bones as rods. This particular design manipulates muscles to replicate a human-like gait, which demonstrates its potential for use as an anatomically correct assistive device (prosthetic, exoskeleton, etc.). Using the [EJ]OpenSim 3.0 simulation environment, we estimated the kinematics and structural integrity of the proposed flexural joint design and determined the actuation strategies for our prototype. Kinematics for the prototype include the mechanical limitations and constraints derived from the simulations. We compared the simulation, physical prototype, and human leg behaviors for various ranges of motion and demonstrated the potential for using [EJ]OpenSim 3.0 as a flexible–rigid modeling and simulation environment.

Design and locomotion analysis of the tetrahedral mobile robot with only revolute joints (TMRR)

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhirui Wang ◽  
Yezhuo Li ◽  
Bo Su ◽  
Lei Jiang ◽  
Ziming Zhao ◽  
...  
Keyword(s):  
Mobile Robot ◽  
Main Body ◽  
Dynamics Analysis ◽  
Content Type ◽  
Displacement Error ◽  
Working Space ◽  
Revolute Joints ◽  
Physical Prototype ◽  
Moving Direction ◽  
Rolling Locomotion

Purpose The purpose of this paper is to introduce a tetrahedral mobile robot with only revolute joints (TMRR). By using rotation actuators, the mechanism of the robot gains favorable working space and eliminates the engineering difficulties caused by the multilevel extension compared with liner actuators. Furthermore, the rolling locomotion is improved to reduce displacement error based on dynamics analysis. Design/methodology/approach The main body of deforming mechanism with a tetrahedral exterior shape is composed of four vertexes and six RRR chains. The mobile robot can achieve the rolling locomotion and reach any position on the ground by orderly driving the rotation actuators. The global kinematics of the mobile modes are analyzed. Dynamics analysis of the robot falling process is carried out during the rolling locomotion, and the rolling locomotion is improved by reducing the collision impulse along with the moving direction. Findings Based on global kinematics analysis of TMRR, the robot can realize the continuous mobility based on rolling gait planning. The main cause of robot displacement error and the corresponding improvement locomotion are gained through dynamic analysis. The results of the theoretical analysis are verified by experiments on a physical prototype. Originality/value The work introduced in this paper is a novel exploration of applying the mechanism with only revolute joints to the field of tetrahedral rolling robots. It is also an attempt to use the improved rolling locomotion making this kind of mobile robot more practical. Meanwhile, the reasonable engineering structure of the robot provides feasibility for load carrying.

scholarly journals Design and Analysis of a Dynamic Loading System for a Morphing Winglet

2021 ◽  
Author(s):  
Raffi Buchkazanian
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Loading ◽  
Structural Integrity ◽  
Load Test ◽  
Proof Of Concept ◽  
Full Scale Test ◽  
Dynamic Load Test ◽  
Loading System ◽  
Scale Test ◽  
Loading Fixture

The following thesis paper investigates the possible methods to perform a dynamic load test on a morphing winglet. A morphing winglet design capable of deflecting in the cant direction was developed by a joint partnership between Ryerson University and Bombardier Aerospace. In order to validate the model and complete a proof of concept, a loading fixture was required to test the structural integrity of the winglet under a defined load. Upon completion of an enumeration study of planar four-bar linkages, a passive R-P-R-P mechanism was designed to apply a constant perpendicular load throughout the cant motion. A design of the half size loading fixture was developed, optimized and manufactured to integrate with an existing cant module. The dynamic loading model was validated by producing a positive correlation between the theoretical analysis and the experimental results, leading to a successful proof of concept for a full scale test.

Fire of steel and composite beam bridges

2019 ◽  
Author(s):  
Henryk Zobel ◽  
Wojciech Karwowski ◽  
Agnieszka Golubińska ◽  
Thakaa Al-Khafaji
Keyword(s):  
Fire Resistance ◽  
Composite Beam ◽  
Structural Integrity ◽  
Bridge Structure ◽  
Long Span ◽  
Long Span Bridge ◽  
Bridge Structures ◽  
Fire Scenarios ◽  
Design Construction ◽  
Cable Stayed Bridges

<p>The problem of bridge fires is growing. Because of a bad experience in Poland, it was decided to improve fire resistance of long span bridge structures, and of cable-stayed bridges in particular. Statistics shows that fire is a real threat to this kind of structure. They also confirm that the worst results of fire are for those with an orthotropic deck rather than with a concrete one. The basic problems to solve are how to predict fire resistance of a particular bridge and how to ensure safety and structural integrity of the bridge structure. Taking into account the fact that bridge standards do not include information relating to fire protection, and fire standards do not determine rules for design, construction and maintenance of such structures, there are no regulations for this problem. Fire scenarios are devoted to buildings, but the thermo-structural behavior of bridges is different.</p>

A User-Driven Design Framework for Coupled-Serial-Chain Mechanism Synthesis for Assisting Sit-to-Stand Motion

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Liuxian Zhu ◽  
Hao Lv ◽  
Li Li ◽  
Xiaofei Xu
Keyword(s):  
Rehabilitation Robot ◽  
Design Framework ◽  
Chain Mechanism ◽  
Mechanism Synthesis ◽  
Sit To Stand ◽  
Serial Chain ◽  
Assistive Robot ◽  
Physical Prototype ◽  
Natural Movement ◽  
Human Joints

Abstract This paper presents a novel coupled-serial-chain (CSC) mechanism based multifunctional rehabilitation robot to assist the patients with lower-limb disability in their sit-to-stand (STS) movement. The CSC mechanism is constructed by coupling the joint rotations of a multilink serial chain with gears and operates by following the natural movement of human joints and limbs during the STS motion. The goal is to design an ergonomic and lightweight assistive robot with CSC mechanism that helps minimize the patient's joint/muscle strength and requires the least number of external actuators. A user-driven design framework is proposed to synthesize the CSC mechanism with type and dimensions personalized to the hip trajectory of an individual user. An example CSC mechanism is generated and verified by virtual prototyping and simulation. A physical prototype of the mechanism is built, which will be tested on the human subject to evaluate its maneuverability and physical compatibility with the subject's STS movement.

Design of an Onboard Directional Anemometer for Bicycles

2020 ◽  
Author(s):  
Valentina Hurtado ◽  
Santiago Arango ◽  
Luis Muñoz ◽  
Omar López
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Velocity ◽  
Design Process ◽  
Design Methodology ◽  
Structural Integrity ◽  
Pitot Tube ◽  
Proof Of Concept ◽  
Large Influence ◽  
Main Component

Abstract Wind speed has large influence on the results of road tests applied to bicycles. For this reason, this paper presents the design process of an onboard anemometer dedicated to bicycle testing. The design provides an affordable way to quantify both magnitude and direction of the wind velocity relative to the bicycle, allowing recording on arbitrary wind conditions that could arise during a test. The design methodology was structured with two major phases. The first was centered on the proof-of-concept for the use of a multi-hole pitot tube as main component for the onboard anemometer. The second was focused on the design of the structure, considering both packaging and structural integrity. The prototype of anemometer was tested in a wind tunnel to verify its performance, and it was also tested under severe vibrations to verify its structural integrity. The results showed that this concept can be used as a part of the bicycle instrumentation for road tests.

Effects of substituting anthropometric joints with revolute joints in humanoid robots and robotic hands: a case study

Robotica ◽  
2013 ◽  
Vol 32 (4) ◽  
pp. 501-513 ◽  
Author(s):  
Mehdi Mousavi ◽  
Aurelio Somà ◽  
Francesco Pescarmona
Keyword(s):  
Human Body ◽  
Humanoid Robots ◽  
Rotational Axis ◽  
Robotic Hands ◽  
Revolute Joints ◽  
Kinematic Study ◽  
Fixed Axis ◽  
Human Joints ◽  
Multi Body

SUMMARYIn the human body there are many joints whose functions are very similar to revolute joints. To avoid the complexity of these joints, they are usually substituted by revolute joints in many humanoid robots. Revolute joints have purely rotational motion along their fixed axis, while real joints in the human body have Instantaneous Rotational Axis (IRA) due to their configuration. Substitution of this kind of human joints with revolute (hinge) joints in robots changes the kinematics of joints. Knowing the exact characteristics of the moving axis of rotation in human joints is a prerequisite for the kinematic study of a joint. Here the main geometrical difference between these kinds of joints in humans and their simplified (hinge-like) models in robots is described. Then, as a case study, the mechanism of the three joints of the index finger are compared with their hinge-like model using a multi-body code to understand when revolute joints can be substituted for anthropometric joints in hand exoskeletons and robotic hands. Furthermore, the position of IRA and its distance from the center of the condyle of the joint are presented. The concept and the results can be extended for other fingers and all similar joints, and can be used in humanoid robots, hand exoskeletons and robotic hands.

scholarly journals Coffee Fun: Gamified Tool Based on the SUM Agile Development Methodology For Video Games

2021 ◽  
Vol 20 (38) ◽  
pp. 159-169
Author(s):  
Manuel Esteban Jaramillo Reinel ◽  
Andrés Felipe Mera Tróchez ◽  
Katerine Márceles Villalba ◽  
Gabriel Elías Chanchí
Keyword(s):  
Video Games ◽  
Video Game ◽  
Serious Games ◽  
Agile Development ◽  
Educational Context ◽  
Simulation Environment ◽  
Development Methodology ◽  
Coffee Beans ◽  
Original Type ◽  
Design Construction

In recent years, serious games have been applied in different contexts of application, highlighting their contribution in the educational context. This original type article presents the design, construction and evaluation of the Coffee Fun video game. Coffee Fun is a video serious game aimed at children aged 8 to 12 years old; the game has as a theme the growing of coffee beans in a simulation environment in which each player helps the growth of this plant by a few tools provided at each level of the game; in the game, different scenarios related to coffee growing environments are presented for each of its stages in a series of levels that the player must overcome to complete the game through a process of learning and entertainment.

A Parallel 5 DOF Positioner for Semi-Spherical Workspaces

2004 ◽  
Author(s):  
Benjamin Maurin ◽  
Bernard Bayle ◽  
Jacques Gangloff ◽  
Michel de Mathelin ◽  
Olivier Piccin
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Medical Applications ◽  
Robotic Device ◽  
X Ray ◽  
Revolute Joints ◽  
X Ray Imaging ◽  
Physical Prototype ◽  
Moving Platform ◽  
Functional Point

In this paper, a new five-degree-of-freedom parallel manipulator is described and modeled. This structure has been specially designed for medical applications that require in the same time mobility, compactness and accuracy around a functional point. The purpose of this robotic device is to help practitioners to perform accurate needle insertions while preserving them from harmful intra-operative X-ray imaging devices. The system is built from revolute joints, among which only five joints are actuated to convey the required five degrees of freedom to its moving platform. A numerical simulation of the workspace and a physical prototype are presented.

scholarly journals A Review on Compliant Joint Mechanisms for Lower Limb Exoskeletons

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Miguel A. Gálvez-Zúñiga ◽  
Alejandro Aceves-López
Keyword(s):  
Human Body ◽  
Lower Limb ◽  
Mathematical Description ◽  
Rapid Development ◽  
Revolute Joints ◽  
Close Interaction ◽  
Compliant Joint ◽  
Internal Forces ◽  
Human Joints

Lower limb exoskeletons are experiencing a rapid development that may suggest a prompt introduction to the market. These devices have an inherent close interaction with the human body; therefore, it is necessary to ensure user’s safety and comfort. The first exoskeletal designs used to represent the human joints as simple revolute joints. This approximation introduces an axial misalignment issue, which generates uncontrollable internal forces. A mathematical description of the said misalignments is provided to better understand the concept and its consequences. This review will only focus on mechanisms aiming to comply with its user.

scholarly journals Periodic dynamic induction control of wind farms: proving the potential in simulations and wind tunnel experiments

2020 ◽  
Vol 5 (1) ◽  
pp. 245-257 ◽  
Author(s):  
Joeri Alexis Frederik ◽  
Robin Weber ◽  
Stefano Cacciola ◽  
Filippo Campagnolo ◽  
Alessandro Croce ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Farm ◽  
Traditional Approach ◽  
Wind Farms ◽  
Simulation Studies ◽  
Proof Of Concept ◽  
Simulation Environment ◽  
Wind Tunnel Experiments ◽  
Alternative Approach ◽  
First Time

Abstract. As wind turbines in a wind farm interact with each other, a control problem arises that has been extensively studied in the literature: how can we optimize the power production of a wind farm as a whole? A traditional approach to this problem is called induction control, in which the power capture of an upstream turbine is lowered for the benefit of downstream machines. In recent simulation studies, an alternative approach, where the induction factor is varied over time, has shown promising results. In this paper, the potential of this dynamic induction control (DIC) approach is further investigated. Only periodic variations, where the input is a sinusoid, are studied. A proof of concept for this periodic DIC approach will be given by the execution of scaled wind tunnel experiments, showing for the first time that this approach can yield power gains in real-world wind farms. Furthermore, the effects on the damage equivalent loads (DEL) of the turbine are evaluated in a simulation environment. These indicate that the increase in DEL on the excited turbine is limited.

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