Design, development, and testing of a lightweight hybrid robotic knee prosthesis

2018 ◽  
Vol 37 (8) ◽  
pp. 953-976 ◽  
Author(s):  
Tommaso Lenzi ◽  
Marco Cempini ◽  
Levi Hargrove ◽  
Todd Kuiken
Keyword(s):  
Electric Motor ◽  
Knee Prosthesis ◽  
Gait Pattern ◽  
Design Development ◽  
Passive Mode ◽  
Active Mode ◽  
Actuation System ◽  
Hybrid Actuation ◽  
And Control ◽  
Stair Ambulation

We present a lightweight robotic knee prosthesis with a novel hybrid actuation system that enables passive and active operation modes. The proposed hybrid knee uses a spring-damper system in combination with an electric motor and transmission system, which can be engaged to provide a stair ambulation capability. In comparison to fully powered prostheses that power all ambulation activities, a hybrid knee prosthesis can achieve significant weight reduction by focusing the design of the actuator on a subset of activities without losing the ability to produce equivalent torque and mechanical power in the active mode. The hybrid knee prototype weighs 1.7 kg, including battery and control, and can provide up to 125 Nm of repetitive torque. Experiments with two transfemoral amputee subjects show that the proposed hybrid knee prosthesis can support walking on level ground in the passive mode, as well as stair ambulation with a reciprocal gait pattern in the active mode.

scholarly journals A Review of Microrobot’s System: Towards System Integration for Autonomous Actuation In Vivo

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1249
Author(s):  
Zhongyi Li ◽  
Chunyang Li ◽  
Lixin Dong ◽  
Jing Zhao
Keyword(s):  
Medical Imaging ◽  
System Integration ◽  
Working Environment ◽  
Delivery Methods ◽  
Actuation System ◽  
Imaging Algorithms ◽  
Hybrid Actuation ◽  
Actuation Systems ◽  
And Control

Microrobots have received great attention due to their great potential in the biomedical field, and there has been extraordinary progress on them in many respects, making it possible to use them in vivo clinically. However, the most important question is how to get microrobots to a given position accurately. Therefore, autonomous actuation technology based on medical imaging has become the solution receiving the most attention considering its low precision and efficiency of manual control. This paper investigates key components of microrobot’s autonomous actuation systems, including actuation systems, medical imaging systems, and control systems, hoping to help realize system integration of them. The hardware integration has two situations according to sharing the transmitting equipment or not, with the consideration of interference, efficiency, microrobot’s material and structure. Furthermore, system integration of hybrid actuation and multimodal imaging can improve the navigation effect of the microrobot. The software integration needs to consider the characteristics and deficiencies of the existing actuation algorithms, imaging algorithms, and the complex 3D working environment in vivo. Additionally, considering the moving distance in the human body, the autonomous actuation system combined with rapid delivery methods can deliver microrobots to specify position rapidly and precisely.

Design, Development, and Control of a Fabric-Based Soft Ankle Module to Mimic Human Ankle Stiffness

2019 ◽  
Author(s):  
Sunny Amatya ◽  
Amir Salimi Lafmejani ◽  
Souvik Poddar ◽  
Saivimal Sridar ◽  
Thomas Sugar ◽  
...  
Keyword(s):  
Design Development ◽  
Ankle Stiffness ◽  
Human Ankle ◽  
And Control

Development of Exoskeleton Suit for Rehabilitation

2013 ◽  
Vol 717 ◽  
pp. 592-597
Author(s):  
Surachai Panich
Keyword(s):  
Lower Limb ◽  
Pid Controller ◽  
Control Algorithm ◽  
Passive Mode ◽  
Active Mode

This paper introduced the rehabilitation for leg lower limp with exoskeleton suit. The rehabilitation is mainly classified in three modes, which are active, passive and active - assistive mode. In active mode, it provides appropriate resistance to the muscles to increase endurance and strength, because the patients must lift leg lower limp by their effort. In passive mode, patients cannot participate in process of rehabilitation and no effort is required, because patients leg lower limb will be driven by exoskeleton suit. In the last active-assistive mode is the combination of active and passive mode for patients, who has capability to move their joints but not reached the desired level. The control algorithm is designed to achieve rehabilitation modes by using classical PID controller.

An electric motor thermal management system for hybrid vehicles: modelling and control

2016 ◽  
Vol 2 (3) ◽  
pp. 207 ◽  
Author(s):  
Xinran ( ◽  
N.A. William) ◽  
N.A. Tao ◽  
Kan Zhou ◽  
John R. Wagner ◽  
...  
Keyword(s):  
Thermal Management ◽  
Electric Motor ◽  
Management System ◽  
Hybrid Vehicles ◽  
Thermal Management System ◽  
And Control

Optimisation of a Pump-Controlled Hydraulic System using Digital Displacement Pumps

2021 ◽  
Author(s):  
L. Viktor Larsson ◽  
Robert Lejonberg ◽  
Liselott Ericson
Keyword(s):  
Electric Motor ◽  
Energy Savings ◽  
High Energy ◽  
Motor Speed ◽  
Efficient Operation ◽  
Pump Speed ◽  
Hardware Configuration ◽  
Control Optimisation ◽  
And Control ◽  
Parasitic Components

When electrifying working machines, energy-efficient operation is key to maximise the use of the limited capacity of on-board batteries. Previous research indicate high energy savings by means of component and system design. In contrast, this paper focuses on how to maximise energy efficiency by means of both design and control optimisation. Simulation-based optimisation and dynamic programming are used to find the optimal electric motor speed trajectory and component sizes for a scooptram machine equipped with pump control, enabled by digital displacement pumps with dynamic flow sharing. The results show that a hardware configuration and control strategy that enable low pump speed minimise drag losses from parasitic components, partly facilitated by the relatively high and operation point-independent efficiencies of the pumps and electric motor. 5–10% cycle energy reductions are indicated, where the higher figure was obtained for simultaneous design and control optimisation. For other, more hydraulic-intense applications, such as excavators, greater reductions could be expected.

scholarly journals Recycling Heat Losses of an Oil-Immersed Transformer: Feasibility Study

2021 ◽  
Vol 21 (1) ◽  
pp. 48-54
Keyword(s):  
High Efficiency ◽  
Power Transformer ◽  
Heat Losses ◽  
Power Transformers ◽  
Passive Mode ◽  
Active Mode ◽  
Short Circuits ◽  
Definition Of ◽  
The Relationship ◽  
Novel Design

The paper investigates the feasibility of adding a liquid heater to an oil-immersed transformer. It proves that design the high efficiency of power transformers, losses due to idling and short circuits are substantial and are scattered in the environment as heat. The paper proposes a novel design that implements a liquid (coolant) heater to enable the unit not only to convert electricity, but also to generate heat. In order to analyze the feasibility of such heat recycling, the authors have developed an equivalent thermal circuit and a mathematical model thereof. Said heater can operate in two modes. In the passive mode, the coolant it contains only absorbs the heat emitted (lost) by the power transformer. In the active mode, it also receives the heat emitted due to the passage of electric current through the pipes of the heater. The paper further introduces the definition of heater efficiency. Studies have shown that up to 50 % of transformer heat losses can be recycled by heating the coolant in the heater. The paper presents the relationship between utilized heat and transformer losses, as well as heater efficiency as a function of coolant flow rate. The heater efficiency exceeds 90 % in the active mode.

STUDY OF THE INFLUENCE OF RFID TAG BENDING ON BASIC CHARACTERISTICS

2021 ◽  
pp. 85-89
Author(s):  
С.М. Фёдоров ◽  
Е.А. Ищенко ◽  
Е.В. Папина ◽  
К.А. Бердников ◽  
Ю.Д. Савкина
Keyword(s):  
Flexible Substrate ◽  
Passive Mode ◽  
Rfid Tag ◽  
Active Mode ◽  
Effective Scattering Area ◽  
Frequency Peak ◽  
Detection Mode ◽  
Basic Characteristics ◽  
Electrodynamic Modeling ◽  
Passive Rfid

Рассматривается пассивная радиочастотная метка, которая находится на гибкой подложке, что приводит к появлению проблемы с изменением характеристик при изгибе метки. В процессе исследования производилось моделирование для трех ситуаций: плоской метки, изогнутой внутрь и наружу. Благодаря современным методам электродинамического моделирования возможно определить все основные характеристики RFID метки - в активном режиме: обратные потери, диаграмму направленности; в пассивном режиме: диаграмму обратного рассеяния, токи и напряжения в нагрузке. При моделировании были построены графики зависимости амплитуд токов и напряжений в нагрузке от частоты, пиковые значения эффективной площади рассеяния. Благодаря полученным данным можно определить наиболее оптимальные частоты для облучения RFID метки, чтобы обеспечить ее работу в активном режиме (высокие токи и напряжения в нагрузке), а также в режиме обнаружения - большие значения ЭПР. Приводятся графики и таблицы для сравнения исследуемых случаев, по которым видны изменения характеристик при изгибе метки, что делает невозможным применение системы в широких диапазонах частот, так как стоит учитывать ее возможные изгибы The article discusses a passive RFID tag that sits on a flexible substrate, which leads to a problem with changing characteristics when the tag is bent. In the course of the study, we carried out modeling for three situations: a flat tag, curved inward and outward. Thanks to modern methods of electrodynamic modeling, it is possible to determine all the main characteristics of an RFID tag - in the active mode: return loss, radiation pattern; in passive mode: diagram of backscatter, currents and voltages in the load. During the simulation, we plotted graphs of the dependence of the amplitudes of currents and voltages in the load on frequency, peak values of the effective scattering area. Thanks to the data obtained, it is possible to determine the most optimal frequencies for irradiation of an RFID tag in order to ensure its operation in an active mode (high currents and voltages in the load), as well as in the detection mode - large ESR values. The article provides graphs and tables for comparing the cases under study, which show changes in characteristics when the tag is bent, which makes it impossible to use the system in wide frequency ranges, since its possible bends should be taken into account

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