Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Stroke-induced hemiparetic gait is characteristically asymmetric and metabolically expensive. Weakness and impaired control of the paretic ankle contribute to reduced forward propulsion and ground clearance—walking subtasks critical for safe and efficient locomotion. Targeted gait interventions that improve paretic ankle function after stroke are therefore warranted. We have developed textile-based, soft wearable robots that transmit mechanical power generated by off-board or body-worn actuators to the paretic ankle using Bowden cables (soft exosuits) and have demonstrated the exosuits can overcome deficits in paretic limb forward propulsion and ground clearance, ultimately reducing the metabolic cost of hemiparetic walking. This study elucidates the biomechanical mechanisms underlying exosuit-induced reductions in metabolic power. We evaluated the relationships between exosuit-induced changes in the body center of mass (COM) power generated by each limb, individual joint powers, and metabolic power. Compared to walking with an exosuit unpowered, exosuit assistance produced more symmetrical COM power generation during the critical period of the step-to-step transition (22.4±6.4% more symmetric). Changes in individual limb COM power were related to changes in paretic (R2= 0.83, P= 0.004) and nonparetic (R2= 0.73, P= 0.014) ankle power. Interestingly, despite the exosuit providing direct assistance to only the paretic limb, changes in metabolic power were related to changes in nonparetic limb COM power (R2= 0.80, P= 0.007), not paretic limb COM power (P> 0.05). These findings provide a fundamental understanding of how individuals poststroke interact with an exosuit to reduce the metabolic cost of hemiparetic walking.Accepted manuscript2019-03-0

Development of automatic manipulators for plastic injection machines

The automotive industry is a competitive sector, always asking for improvements in productivity, efficiency and quality. This is the reason why the demand for automation of processes arises, resulting in relying less on manpower. Bowden cables are mechanical elements that allow the transmission of motion between two or more systems. They are most of the time not visible for the user. Some examples of applications inside the car are opening doors, windows, seat’s adjustment, among many others. At present, the production of Bowden cables is done by multiple working stations with multiple operators. This work is focused on the workstation where the end of the conduit is injected. At the moment, there are injection machines with a capacity of 8 conduits at the same time and one operator at every injection machine. These injection machines need a lot of space, spend a lot of energy and usually present persistent breakdown problems, needing maintenance. The future outlook of the company is, to have smaller injection machines with a capacity of 4 conduits at a time and one operator for 2 injection machines. These injection machines are easier in maintenance and also occupy less space, consuming less energy as well. The main goal for this project is to make it possible to have 1 operator at 2 injection machines. The possibility to fully automate was rejected as it is really hard to automate the feeding of the conduits in the injection machines due to low stiffness of the conduits, becoming hard to align them in the mould. The proposed solution to make this happens is to design a manipulator to take out the 4 conduits and the scrap out of the mould. The scrap and the conduits then need to be separated, scrap to a recycling box and the conduits to a production/supply chain box. The manipulator has been successfully designed, after a thorough comparison of a variety of possibilities. All the components that were needed for this concept have successfully been defined, calculated, selected and integrated into the design. After the designing process, a budget and payback calculation has been done, as well as a return of investment. Lastly, a maintenance manual and an assembly manual has been elaborated in order to ease the assembly of all the components. The results after implementing the designed solutions are a reduction in energy consumption of the injection peocess (79,8%) and an improvement in productivity (12,0%).A indústria automóvel é um setor competitivo, mas sempre ávido por melhorias de produtividade, eficiência e qualidade. É por esse motivo que surge a procura pela automação de processos, resultando na necessidade de menos recursos humanos. Os cabos de comando são elementos mecânicos que permitem a transmissão de movimento entre dois ou mais sistemas. Na maioria das vezes, eles não são visíveis para o utilizador. Alguns exemplos de aplicações dentro do carro são abrir portas, janelas, ajuste de assentos, entre muitos outros. Atualmente, a produção de cabos de comando é feita em várias estações de trabalho através de vários operadores. Este trabalho está focado na estação de trabalho onde a espiral é sujeita à injeção de terminais. Atualmente, existem máquinas de injeção com capacidade para 8 espirais ao mesmo tempo e um operador em cada máquina de injeção. Essas máquinas de injeção ocupam muito espaço e apresentam problemas constantes de manutenção. A perspectiva futura da empresa é ter máquinas de injeção com menor volume e capacidade para injetar em 4 espirais de cada vez e necessitando apenas de um operador para cada duas máquinas de injeção. Essas máquinas de injeção são mais fáceis de gerir em termos de manutenção e também ocupam menos espaço. O principal objetivo deste projeto é tornar possível um operador em duas máquinas de injeção. A possibilidade de automatizar completamente o processo foi rejeitada, pois é realmente difícil automatizar a alimentação das espirais nas máquinas de injeção. A razão por detrás disso é o alinhamento de alguns tipos de espiral. A solução proposta para fazer isso acontecer é projetar um manipulador para retirar as 4 espirais e os canais de alimentação/gitos do molde. A sucata e as espirais precisam ser separadas, sendo a sucata encaminhada para uma caixa para reciclagem e as espirais para uma caixa de produção/logística interna. Os resultados após a implementação das soluções projetadas são uma redução no consumo de energia do processo de injeção (79,8%) e uma melhoria na produtividade (12,0%)

Design, construction and testing of an 3-axis joint system

El trabajo de fin de master ha consistido en el diseño y montaje de un prototipo de maquina con 3 grados de rotacion que será usado en un robot que se encarge del mantenimiento automatico de jardines verticales.Para desarrollar este prototipo se ha creado una lista con los requerimientos generales del sistema y,de acuerdo con estos requerimientos, se han seleccionado una combinación de articulaciones y motores que permitan moverse al sistema de la forma deseada.Para finalizar se ha diseñado y producido una base para colocar todos los elementos del sistema y se ha testeado las carácteristicas del prototipo.<br /

Investigations on the oxidation of Zn-coated steel cables

The automotive component industry has been constantly being studying to improve its performance. Bowden cables are present in opening doors, moving windows and others. In braided cables formed by galvanized wires with Zn steel exposed to the usual environmental conditions, the generation of ZnO appears, a phenomenon known as "white corrosion". The investigation consisted of mitigating the causes of the ZnO formation. Scanning electron microscopy (SEM) and Electron Probe Micro-Analyzer (EPMA) technology, allowed to detect that the generation of ZnO was induced by the presence of nucleating elements of ZnO on the surface of the steel cable before galvanizing with Zn. The S, Cl and O became visible in the interface between coating and substrate. This allowed concluding, under the coating, there were harmful products capable of triggering the ZnO nucleation reaction. So, the storage and cleaning of the steel wire before galvanizing is essential to prevent the ZnO formation.The Authors would like to thank to Mr. Rui Rocha from CEMUP due to is proactive collaboration in seeking the best images through SEM equipment. The strong cooperation of FicoCables company is also deeply acknowledge. Moreover, the support of CETRIB (Prof. Jorge Seabra) is also strongly appreciatedinfo:eu-repo/semantics/publishedVersio

Design and Control of the McKibben Artificial Muscles Actuated Humanoid Manipulator

The McKibben Pneumatic Artificial Muscles (PAMs) are expected to endow the advanced robots with the ability of coexisting and cooperating with humans. However, the application of PAMs is still severely hindered by some critical issues. Focusing on the bionic design issue, this chapter in detail presents the design of a 7-degree-of-freedom (DOF) human-arm-like manipulator. It takes the antagonized PAMs and Bowden cables to mimic the muscle-tendon-ligament structure of human arm by elaborately configuring the DOFs and flexibly deploying the routing of Bowden cables; as a result, the DOFs of the analog shoulder, elbow, and wrist of the robotic arm intersect at a point respectively and the motion of these DOFs is independent from each other for convenience of human-like motion. The model imprecision caused by the strong nonlinearity is universally acknowledged as a main drawback of the PAM systems. Focusing on this issue, this chapter views the model imprecision as an internal disturbance, and presents an approach that observe these disturbances with extended-state-observer (ESO) and compensate them with full-order-sliding-mode-controller (fSMC), via experiments validated the human-like motion performance with expected robustness and tracking accuracy. Finally, some variants of PAMs for remedying the drawbacks of the PAM systems are discussed

SonoProbe

The current ultrasound probes used in hospitals today use the same design produced in the mid 90s. Ultrasound probes consist of a transducer at the end of a handle. To perform an exam, an ultrasound technician (sonographers) must manipulate the probe at the wrist. To produce a clear image, the technician must apply pressure against the patient at different angles. Due to the extensive rotational movement and pressure the wrist takes when scanning a patient with an ultrasound probe, there is a high rate of carpal tunnel and other wrist injuries in sonographers. This new ultrasound probe will take the rotational movement out of the technicians wrist and isolate the rotational movement to the probe. This rotational movement is achieved by a swiveling transducer head. The majority of the construction was conducted using the machine shop as well as the Senior Project Lab in Hogue Hall at Central Washington University. The probe must withstand up to 40 pounds of vertical force from the grip to the head of the probe. The head must also perform the full range of movement in less than 2 seconds. Different sized pulley wheels and programed speeds are tested to achieve these operation standards

Studying the ZnO formation in coated steel wire ropes for the automotive industry

30th International Conference on Flexible Automation and Intelligent Manufacturing (FAIM2021) 15-18 June 2021, Athens, GreeceBowden cables are abundantly applied in the automotive assembly lines leading to drive various devices, such as opening trunk or the fuel tank cap, triggering the handbrake, opening the doors, etc. The cable used in automotive metallic harness is commonly constituted of braided wire galvanized steel, which has been studied to resist the weather aggressions typically imposed by the conditions under which usually work. However, to allow this operating in a steady state way, the braided wire must have the appropriate quality. This work study the reasons of the formation of relatively abundant quantities of zinc oxide (ZnO) in metallic cables used in the automotive industry, a few weeks after their manufacture. It was concluded that there were serious shortcomings of cable cleaning between the wire forming operations and galvanizing, with deposition of ZnO enhancing elements in the interface, which would prove to be crucial to nucleation and development of ZnO on the surface. Thus, the main contribution of this work is to identify and describe the elements able to generate ZnO in coated steel wires, avoiding this phenomenon in the industry.info:eu-repo/semantics/publishedVersio