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1

Design and modeling of an exoskeleton torque sensor

Herbin P.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2017

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nr 51 (123)

89--94

EN

Controlling the upper limb with force feedback requires the continuous measurement of multiple values, so it is necessary to use a specific measuring system. The position of the joints and the torque produced by the drives are the basic feedbacks necessary for control. Measurement of the joint positions does not cause complications, while measurement of the driving torque is much more complex. This article describes the methods of implementing an exoskeleton drive system through a closed loop conduit system based on Bowden cables, and the integration of a torque sensor within the wheel of the exoskeleton. The integration of the sensor within a mechanical part of the construction of the exoskeleton is the main advantage of the developed sensor because it does not affect the dynamics of the exoskeleton. This article presents the process of designing, calibrating and validating the proposed link wheel torque sensor.

2

Modelowanie pasa biodrowego Systemu Pionizacji i Wspomagania Ruchu

Credo W., Jasińska-Choromańska D.

Pomiary Automatyka Kontrola

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2014

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R. 60, nr 4

212--215

PL

W artykule opisano problem projektowania pasa biodrowego stanowiącego element składowy robota ortotycznego. Pas ten pełni istotną funkcję w mechanicznej strukturze systemu. Dla mechanizmów robota jest on ostoją, czyli zespołem zapewniającym stałe, wzajemne położenie elementów łańcuchów kinematycznych obu kończyn. Z tego względu musi on spełniać wymagania dużej sztywności i określonej wytrzymałości. Pas biodrowy służy ponadto do połączenia systemu z tułowiem użytkownika. W tym przypadku ważne są zasady ergonomii takie jak możliwość łatwego ubierania systemu i wygoda jego użytkowania. Wiąże się to z potrzebą wprowadzenia niezbędnych podatności i nieciągłości mechanicznych, które utrudniają osiągnięcie wymaganych charakterystyk wytrzymało-ściowych. Pogodzenie tych sprzeczności jest rolą konstruktora. Przeprowadzone badania wytrzymałościowe, wykorzystujące metodę elementów skończonych pozwoliły na wybranie konstrukcji pasa biodrowego, który przy spełnieniu podstawowych wymagań, umożliwił ograniczenie masy elementu.

EN

The paper describes a problem related to design of a hip belt, which is a member of an orthotic robot. The belt plays an important role in the mechanical structure of the system. It is a bearing frame for mechanisms of the robot, i.e. it is a unit that ensures a constant mutual position of the members of kinematic chains of both limbs. Because of this fact, it must satisfy requirements pertaining to high rigidity and appropriate mechanical strength. Besides, the hip belt serves also a purpose of connecting the system with the user’s trunk. In this case, the principles related to ergonomics are of utmost importance: it must be easy for the user to put on the system and to use it in a comfortable way. This is connected with a necessity of introducing indispensable mechanical compliances and discontinuities, which makes it difficult to obtain the required strength characteristics. To reconcile these contradictions is a task of the design engineer, who is expected to strike a happy medium. Studies related to the strength, using the finite element method, that were carried out, allowed one to choose a design of the hip belt, which made it possible to reduce the mass of this element and to meet the basic requirements at the same time.

3

Selection of Drives for Orthotic Robot Based on Simulation Studies

Bagiński K., Wierciak J.

Machine Dynamics Research

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2012

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Vol. 36, No. 1

5-14

EN

Orthotic robots seem to be very sophisticated mechatronic devices as they are expected to reflect natural movements of human limbs. Drive systems in such robots are subjected to active, frictional and inertial loads varying significantly. This eliminates possibility of using traditional algorithms of designing drives. When selecting electric drives for robot designed for people with paraplegia a special method was developed and used. It employs computer simulation in two phases of design. First it is used to determine the actual demand for driving torque during the gait cycle. Then, each of the preselected motors is tested by means of simulation in order to verify, whether it meets the formulated functional and operational requirements. In the paper details of simulation software as well as exemplary results of tests are presented.

4

Making Use of Anthropometric Data while Designing Drive Units of an Orthotic Robot

Jasińska-Choromańska D., Credo W., Szykiedans K.

Machine Dynamics Research

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2012

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Vol. 36, No. 1

90-98

EN

The paper describes a project whose aim was elaboration and building of original physical models of drives to be applied in a System for Verticalization and Aiding the Motion (SVAM). The system is intended for individuals suffering from paresis of the lower limbs, what refers to the latest trends in the field of bionics (Pons, 2008; Zielińska, 2003). According to the proposed solution a disabled person moves about owing to application of a mechanical system attached to his lower limbs. The system replaces functions of the limbs by a forced motion, reconstructing in a large measure the natural movement of the lower limbs (Bagiński et al., 2011; Jasińska-Choromańska et al., 2010; Wierciak et al., 2011). The paper discusses the problems related to selection of drive units of the system.

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Symulacyjny model układów wykonawczych robota ortotycznego

Bagiński K., Wierciak J., Jasińska-Choromańska D

Pomiary Automatyka Kontrola

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2011

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R. 57, nr 6

583-586

PL

W Zakładzie Konstrukcji Urządzeń Precyzyjnych na Wydziale Mechatroniki Politechniki Warszawskiej trwają prace nad systemem do pionizacji i realizowania chodu osób z bezwładem kończyn dolnych. Projektowanie urządzenia jest wspomagane badaniami modelowymi. W artykule przedstawiono symulacyjny model elektromechanicznej części systemu opracowany w środowisku Matlab/SimMechanics. Model wykorzystano m.in. do wyznaczenia zapotrzebowania energetycznego układów wykonawczych i oceny błędów odwzorowania profili ruchu.

EN

In the Division of Design of Precision Devices at the Faculty of Mechatronics of Warsaw University of Technology works there are performed upon a system for verticalisation and substituting gait for people with paresis (Fig. 1). Works are supported with simulation software. Simulation model of the system actuators is described in the paper. The purpose of simulation was to estimate energy consumption of actuators and to assess quality of their movements. Main assumption for the model is that mechanisms activating user's legs are of a planar kind. Matlab-SimMechanics mathematical environment was used for modelling. Structure of the model is presented in Fig. 2. Parts of human body are sources of load for actuators as described by eq. (2) and (3). Their parameters are inserted into "body" blocs (Fig. 3), which represent stiff elements of mechanisms in the model. Mechanical contact between the device and a ground was modelled as reaction forces occurring in "foot" parts of the device when distance between them and the ground is less than the assumed value. The drives of actuators' employ DC motors equipped with reduction gearboxes (Fig. 4). Typical equations (4) - (9) were used for modelling DC motors and gears. Input signals are reference angular displacements of joints expressed in the form of functions approximating experimental data (Fig. 5). Simulation experiments revealed strong relation between length of gait cycle and energy consumption of actuators (Fig. 6). Reduction gear ratio also influences energy needs as well as quality of the device movements (Fig. 8). The model is being currently modified and enhanced in order to be used at the next stages of design process.

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Koncepcja systemu sterowania urządzenia do wspomagania chodu

Wierciak J., Jasińska-Choromańska D, Szykiedans K., Bartyś M.

Pomiary Automatyka Kontrola

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2011

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R. 57, nr 9

1016-1019

PL

Mechatronika, jako koncepcja budowy urządzeń jest obecna niemal we wszystkich działach techniki. Rozwój mikroprocesorowych układów przetwarzania danych, a także postęp w dziedzinie budowy układów wykonawczych i pomiarowych stwarzają możliwości realizowania przez urządzenia funkcji, które jeszcze do niedawna pozostawały jedynie w sferze marzeń. Postęp nie ominął również medycyny, a ściślej wyposażenia technicznego pracującego na rzecz osób chorych. Roboty ortotyczne, których szybki rozwój następuje w wielu ośrodkach naukowych na całym świecie, zastępują u ludzi utracone funkcje ruchowe. Autorzy pracują nad urządzeniem do pionizacji i wymuszania chodu osób z bezwładem nóg. W artykule przedstawiono koncepcję systemu sterowania opracowywanego urządzenia.

EN

Mechatronics seems to be nowadays the leading idea of design of machines and devices. Integration of mechanic devices with the powerful microelectronic technology forced synergy effects resulting in new applications also in medical domain. Here, wearable robots are most spectacular examples. They are person-oriented robots that may be defined as those worn by human operators, whether to support the function of a limb or to replace it completely. The authors focussed their attention on the development of an orthotic robot suited for people with paresis of lower limbs (Fig. 1). The role of the robot is to improve standard of life of handicapped people. However, for safety reasons, its usage needs additional assistance of third party persons. It leads to a conclusion, that control system of the device should be designed in such a way that movements of limbs are allowed only and only in cases when all safety conditions are fulfilled. Upon this statement, the device under design can be classified as a self optimising system. The general structure of such a system is shown in Fig. 2. This system consists of: knowledge base, multi- control subsystem, communication ports and inference machines. The block diagram of automatic control system is depicted in Fig. 3. The main purpose of knowledge base is to store and update reference data for decisions upon the device performance. This data contains records of values of selected signals, collecting information about the state of the device and a robot user, in order to detect non-safety behaviour. Tilt of the user's body and acceleration of its certain parts, as well as reaction forces between feet and crushes against ground can be considered as signals useful for decision making. A structure of the control system meeting the above considerations is presented in Fig. 4. A brief survey of data transmission protocols was carried out. A survey was focused on systems used for industrial applications taking into considerations its approved high immune against electromagnetic field transients and easiness of building redundant structures of communication networks and controllers. Finally, CAN standard was proposed as a communication protocol for the device broadly used in automotive industry (Fig. 5). In the conclusions future works are presented together with the risk analysis.