The following document shows in detail the process of design, construction and operation by applying a mechatronic system to an arm operated with pneumatic muscles. The arm has 3 degrees of freedom through which movements of flexion, extension, adduction and abduction are mainly generated, which will be described inside the document. The prototype designed implements a mechanical, electronic development and control interface.
International Journal of Mechanical Engineering and Technology (IJMET) Volume 10, Issue 12, December 2019, pp 367-379, Article ID: IJMET_10_12_039 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=12 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication PROTOTYPE OF A HUMAN UPPER LIMB DRIVEN BY PNEUMATIC MUSCLES Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez Universidad Militar Nueva Granada, Programa de Ingeniería Mecatrónica, Grupo de Investigación en Mecatrónica DAVINCI, Cr 11 No 101-80 Bogotá D.C, Colombia ABSTRACT The following document shows in detail the process of design, construction and operation by applying a mechatronic system to an arm operated with pneumatic muscles The arm has degrees of freedom through which movements of flexion, extension, adduction and abduction are mainly generated, which will be described inside the document The prototype designed implements a mechanical, electronic development and control interface Keywords: Pneumatic Muscle, Upper Limb assistive technology, Biomechatronics Design Cite this Article: Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez, Prototype of a Human Upper Limb Driven by Pneumatic Muscles International Journal of Mechanical Engineering and Technology 10(12), 2019, pp 367-379 http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=12 INTRODUCTION The number of people who lose an upper limb in Colombia every year due to causes such as illness, an accident or as a consequence of the armed conflict according to the Colombian Association of Physical Medicine and Rehabilitation is approximately 200 to 300 people per 100 thousand inhabitants, which is why there is a need to replace the missing members with biomechatronic elements that resemble real members, either to replace the loss or to replace dangerous tasks where it is necessary to apply a movement In Colombia, the use of robotic devices in health applications is limited due to the high costs and the lack of availability of modern technologies, as well as the need to search for mechanisms to solve problems such as those described above This work raises the possibility of generating a performance system for upper limb based on unconventional actuators, as is the case of pneumatic muscles, for this purpose a characterization of a McKiben type muscle is performed [10], the system is then simulated in an environment of Matlab and later emulate the movements of the shoulder and elbow in the upper limb on a physical device in order to validate the functionality of the system http://www.iaeme.com/IJMET/index.asp 367 editor@iaeme.com Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez THEORETICAL FRAMEWORK The system of locomotion of the human body is composed mainly of bones, muscles, joints and tendons, which, together, function as support and protection of the other organs of the body which allows the human being to interact with the environment that surrounds it Broadly speaking, the bones are responsible for maintaining the structure and protecting the other organs of the body, it is a resistant tissue, which allows movement, support and balance [8], the muscles are contractile tissues that generate displacements when contracting and / or relax and which are attached to the bones through the tendons Each part of the body is composed of mechanisms that provide the ability to move, such as the legs, feet, arms, hands, hips, head and shoulders The arm is a fundamental organ for the realization of daily activities that have to with physical strength, they also intervene in the functions of balance The muscles of the arms are among the most powerful in the human body These being the ones that are located from the hand to the shoulder blade passing through the humerus [7] The bones that make up the arm are the humerus, which articulates with the scapula (shoulder), the ulna and the radius (Forearm), Figure The basic movements that a human arm can perform are: Abduction, Adduction, Flexion, Extension and rotation To explain the types of movements it is necessary to define the planes in which each one executes since as we know, the human being can move in three dimensions, but generally each one of the movements that the arm has is executed in two dimensions, In addition to the elements that intervene in it and generate movement as they are the bones, muscles and joints [6] Figure Bone structure of the human arm The anatomical planes are spatial references that take as reference axes the Cartesian plane through which they allow to describe the position of the different organs and systems [9], [7] http://www.iaeme.com/IJMET/index.asp 368 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles Figure Planes of the human body Flexion: It is performed in three times, the first reaches 60º, and is given by the deltoid, the coracobrachial and pectoral muscle, the second reaches 120º and the trapeze intervenes and the third reaches 180º with the collaboration of the rachis This movement takes place around the transverse axis and describes the movement when the arm is raised forward On the shoulder, it is measured with the value of the angle that is created between the arm and the longitudinal axis in the Flexion-Extension plane [11] Extension: Reaches 50 degrees in a single time, the muscles involved in this movement are the round, the deltoid and the latissimus dorsi This movement is opposed to flexion, it also takes place on the transverse axis, if the arm is in flexion, it is the movement that returns it to the body again Abduction: As in the flexion, the 180º rotation is performed in three times, first at 60º where the deltoid and supraspinatus intervene, the second at 120º involves the trapezius and the third the spine Both Abduction and Adduction take place around the anteroposterior axis and happens when the arm moves away from the body Flexion and extension of the Flexion and extension of the Abduction and adduction of arm shoulder the shoulder Biceps contracted; Triceps Anterior deltoid, Pectoralis Deltoid, biceps, supraspinatus relaxed major, biceps and coracobrachialis muscle Figure Some muscle groups involved in arm movement http://www.iaeme.com/IJMET/index.asp 369 editor@iaeme.com Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez Adduction: Reaches 30º, the muscles intervene: broad dorsal, greater round, subscapular and pectoral It occurs when the arm approaches the body In the shoulder they are measured with the angle that is formed between the arm and the longitudinal axis Rotation: The shoulder externally rotates 80 degrees, the infraspinatus and greater round muscles intervene, and internally 30º intervene dorsal, round, subscapular and pectoral It takes place on the longitudinal axis of the member; it is the rotation of the member on its own axis The above can be seen in Figure 3 PNEUMATIC MUSCLE An actuator is defined as a mechanical device capable of generating a force to achieve a displacement, the force that causes the actuator Among the conventional ones you can find pneumatic, hydraulic and motor-electric types An alternative to emulate a biological muscle is the pneumatic muscle that has its origin by the physicist Joseph L McKibben in the decade of the 50's The emulation consists in injecting compressed air to the pneumatic muscle causing a contraction and a linear movement The linear movement can be transmitted by means of tendons that are connected to rigid elements to transmit a movement, in Figure (FESTO, 2019) a muscle with and without pressure is shown, the difference in length can be observed, these elements are composed of a tube of rubber covered by a layer of twisted fibers of helical form, closed to the ends, their characteristics are the dynamic behavior, the lightness, the reduced cost, great initial strength and versatility Figure Festo Pneumatic Muscle When pressurized air is introduced through the rubber tube, it is inflated, expanding transversely, which causes the mesh to generate tension in a direction tangential to the tube and orthogonal to the axis of rotation, which translates into a displacement and force axial The nominal length of the muscle is defined to be without pressure or load, this corresponds to the length of the rubber tube The muscle expands when subjected to a pulling force When pressure is applied shrinkage occurs decreasing its length DEVELOPMENT AND CHARACTERIZATION OF THE PNEUMATIC MUSCLE For the construction of a prototype, materials that meet the characteristics of elasticity, strength and displacement are taken into account in order to achieve a contraction from an established pressure [3] The materials used for the construction of the muscle are: Latex Hose, Braided Mesh, Mooring, Pressure Hose FESTO ¼ " Characterization: To perform this procedure, it should be noted that a muscle with the following dimensions was taken as reference: Length: 20.5 cm, diameter of the hose: cm A pressure variation from bar to 4.5 bar is carried out Figure shows the muscle with load and no load in real assembly http://www.iaeme.com/IJMET/index.asp 370 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles Actuator characterization without whit charge charge P d d [Bar] [cm] [cm] 20,5 20,5 0,5 20,4 20,4 20 20,3 1,5 19,9 20,1 19,5 19,8 2,5 19,2 19,3 18,6 18,7 3,5 18,1 18,3 17,9 17,7 4,5 17,3 17,4 21 20.5 20 19.5 19 18.5 18 17.5 17 0.5 1.5 2.5 3.5 4.5 Figure Variation of the length of the artificial muscle with variation of pressure With the data obtained in Table 1, it is interpolated to determine the equation that defines the behavior of the unloaded muscle: (1) The equation that describes the behavior of the muscle with load is: (2) When performing the characterization of the pneumatic muscle with a certain load, it can be determined that the displacement is evidently reduced, the applied force depends on the displacement of the muscle when introducing pressure, in Figure the behavior of the loaded muscle is observed Figure Pneumatic Muscle Finally, the behavior of the muscle in terms of the force that it exerts is presented in Figure http://www.iaeme.com/IJMET/index.asp 371 editor@iaeme.com Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez P [Bar] 0,5 1,5 2,5 3,5 4,5 F [N] 1,4 2,8 5,6 9,8 16,8 25,5 30,8 39,2 43,4 45 40 35 30 25 20 15 10 0 Figure Variation of force versus variation of pressure ANTHROPOMORPHIC ARM For the realization of the CAD model of the arm, the bone structure of the arm is taken into account, since this is going to be the support of the muscles, as it is handled in the real environment It was exported to SolidWorks to work the arm with Simmechanics and to control the rotation angles of each of the joints from Matlab® Figure 8: CAD design in SolidWorks 5.1 Muscular behavior Analysis by Opensim Opensim is an open source software that allows to build and analyze models of the skeletal muscle system of the human being, in addition to the dynamic simulations of movements, it has a graphical user interface where the work that is being performed is visualized It is implemented in a large number of applications such as biomechanical research, medical device design, orthopedics, rehabilitation, ergonomic analysis, robotic research and education mainly Having the point of reference as the thorax, we proceed to define the movements that will make the shoulder and arm, taking into account the degrees of freedom that a human arm is able to rotate and / or move http://www.iaeme.com/IJMET/index.asp 372 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles For the forward-backward movement (adduction) of the shoulder, degrees of freedom are taken from -90 ° to 130 °, shoulder elevation (flexion) is handled from ° to 180 ° (shoulder movement from top to bottom) in orientation perpendicular to the axis of the torx, rotation of the shoulder is between -90 ° to 20 ° In the case of the arm, a range of ° to 130 ° is used for bending Next in Figures 9, Figure 10 and Figure 11 is shown as from the software and the movements made by the shoulder and elbow, it can be determined how the muscles are coupled to the bone structure, this in order to perform an adequate emulation Figure Shoulder Flex Movement Figure 10 Shoulder Adduction movement Figure 11 Elbow flexion movement 5.2 Bend Elbow Movement Shown in Figure 12 of the behavior of the muscles involved in the movement of flexion, such as biceps and triceps, for the taking of the curves was determined the position of the arm at 130 ° which is the maximum angle of flexion http://www.iaeme.com/IJMET/index.asp 373 editor@iaeme.com Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez It can be observed that, in the movement of the flexed arm, the triceps muscle lengthens approximately mm, while the biceps contracts mm Figure 12 Graph OpenSim Flexion 5.3 Shoulder Flexion It is known all the muscles mentioned above, it should be noted that it depends on the position where the arm is, if it is in flexion or extension, its muscle groups are extended or contracted Figure 13 Figure 13 Graphical Shoulder Flexion in OpenSIm 5.4 Shoulder Adduction Figure 14 Graphical Shoulder Adduction in OpenSim http://www.iaeme.com/IJMET/index.asp 374 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles 5.5 Interface Development in Matlab® In order to implement the CAD model developed in MATLAB, it is necessary to use Simmechanics, the SolidWorks model is exported in XML format, then after having installed the necessary complements, it opens in Matlab which converts it to SLX (Simulink) format Under the block diagrams that are generated, the rotations and movements linked to the GUIDE interface are worked and manipulated, Figure 15 Figure 15 Model Simmechanics MATLAB For the development of the interface, three sliders were implemented that vary the angle of the three rotations; Elbow flexion, and rotation up-down and left-right of the shoulder The interface shows the value of the elongation of each muscle implemented for the movements, in addition to the state in which it is, for example, if the arm is decreasing the angle means that it is in extension while if it increases it is in flexion, and finally, according to the equations, the necessary pressure is determined so that the muscle is able to move to the desired angle For example, for the calculation of movement of the biceps and triceps muscle, Eq (1) was used, where the behavior of the muscle was determined when the angle of rotation was changed, then Eq (2) was used to establish the muscle behavior with load to elongation changes, and thus determine the pressure required to achieve the desired movement http://www.iaeme.com/IJMET/index.asp 375 editor@iaeme.com Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez Figure 16 Graphical Interface Matlab The Biceps and Triceps muscles are analyzed at the 90 ° angle For the movement of Flexion and Extension of the Elbow Figure 17 Elongation-pressure chart In the case of Triceps at 90 ° the muscle is elongated approximately 0.175 cm, as the elongation increases, the pressure increases because the muscle is contracting Figure 18 Simulation angle variation For the other muscle groups we proceed in the same way http://www.iaeme.com/IJMET/index.asp 376 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles CONSTRUCTION AND COMPARISON OF THE MODEL PHYSICAL IN FRONT OF THE SIMULATION OF THE ARM ANTHROPOMORPHIC For the construction of the anthropomorphic arm it was established before it had the measurements of the body of a person of 1.60 m in height, therefore, its dimensions are: The humerus, the radio cube, and trunk height In the OpenSim model the torx was established as earth and the movements were defined around its axis, in this case also the thoracic region works as the base of the system The physical model has a head, Toraxica region, and both arms, but only in one of them is the muscular system implemented as a check The design of the pneumatic muscles went through several stages of improvement, since, when handled with air, it is very prone to leakage Finally, the final model has the muscle groups mentioned in the document, one muscle makes up the triceps, another the biceps, another the muscle group pectoral, the dorsal, the Latissimuss and the trapeze, each one was implemented one by one to characterize the movement expressed 5.1 Flexion and Extension of the Elbow It shows the prototype designed to check the movements of the arm by implementing pneumatic muscles, as for this first movement, the arm does not reach the level of 130 ° flexion because it is necessary to develop more muscles complementary to the system, the arm reaches a maximum flexion of 90 °, as far as the extension of the same the movement is immediate Figure 22: Flexion Extension Prototype The movements of flexion (Left), the state of the normal arm (center) and the extension to the back (Right) are minimized, the flexion angle is approximately 20 ° maximum due to the design of the prototype, with which it was sought simulate a muscle group such as pectoral, which is a large muscle in size, in two muscle strips, things that influenced the handling of the positions of the same Figure 23: Flexion Shoulder Extension Prototype http://www.iaeme.com/IJMET/index.asp 377 editor@iaeme.com Laura A Beltrán, Oscar F Avilés S, Mauricio Mauledoux, Oswaldo Rivera, Robinson Jiménez 5.2 Adduction and Abduction of the Shoulder The manner in which adduction is followed in a reduced manner is shown and then abduction of the shoulder, the elevation angle was 30 °, emphasizing the aforementioned problem regarding the structure Figure 24: Shoulder Adduction Prototype CONCLUSIONS The development of a homemade pneumatic muscle as an actuator is a very viable solution if one looks for strength and economy, its construction is elementary for its correct functioning, since it is necessary to take into account the minor losses of pressure for the muscle to be able to more route, at the time of its characterization should be taken into account the values of length, cross-sectional area, pressure and load that will be handled, making tests with maximum force, and minimum necessary for the muscle to contract When implemented as a muscle group that simulates the movements of the human arm, is not very accurate in terms of position requirements, it is due to the way the muscles were coupled, its coupling was made with a thread called Hactan, which is Rigid enough, in the first measurement the coupling was made with Nylon, but since the muscle generates an approximate force of 10 N it was able to yield With the thread, the movement was generated, but it was quite brusque and not very exact Another aspect that stands out in terms of accuracy is mentioned above, the lack of muscles to achieve a more stable and similar movement A prototype of an anthropomorphic robot with three degrees of freedom and rotating articulations was designed and built in order to show in a general way the application of pneumatic muscles for this purpose In addition to this, an analysis and simulation tool was developed that allows to verify the mathematical foundations with the real application The analysis developed by OpenSim, was necessary to define the behavior of each muscle with the respective movements, in addition to the muscle groups required for each of the movements that were allowed in the arm, push-ups, extensions, abductions and adductions The development of the simulation under the MATLAB Software has the necessary indications to understand how arm movement develops, which are the antagonistic muscles and the pressures necessary to achieve, under ideal conditions, the control of angular position, in addition to a visual feedback to identify the position to which the arm leads with the variation of the angles According to the analysis of art states, the developed anthropomorphic arm has lightness, strength and economy to those developed previously, it is clearly necessary to make the model more stable, it is a first prototype of an excellent option to work as a prosthesis or as a manipulator distant http://www.iaeme.com/IJMET/index.asp 378 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles Finally, it is important to highlight the differences between the pneumatic muscle and the real one, the main ones are the speed of movement, the elongation of each one, and in my opinion one of the most important, the coupling to the bone system ACKNOWLEDGEMENTS This work was financially supported by the Vice presidency for Research of Universidad Militar Nueva Granada, through the project ING-2657 REFERENCES [1] Boblan, Ivo & Bannasch, Rudolf & Schulz, Andreas & Schwenk, Hartmut (2006) A Human-Like Robot Torso ZAR5 with Fluidic Muscles: Toward a Common Platform for Embodied AI 4850 347-357 10.1007/978-3-540-77296-5_31 [2] Daniel.D.T, Cox.J, The Dymanic Model of a three degree of Freedom Parallel Robotic Shoulder module,Texas, 1999 [3] FESTO, Músculo neumático DMSP, (2019)» [On https://www.festo.com/net/SupportPortal/Files/12361/PSI_501_2_es.pdf [4] Gonzalez D, Mecanismos de transmisión y actuadores utilizados en prótesis de mano, Memorias del XV Congreso Internacional anual de la SOSIM, O Sonora, México, 2009 [5] Imani N, El músculo neumático,» 2002 Universitat de Barcelona, Materials, Barcelona,Espa [6] LELOIR, Fundamentos de Biomecánica Articular, línea].http://imedleloir.com.ar/documentos/Biomecanica_articular.pdf [7] Juquilpan A, Antropometría y Ergonomía, México, 2010 ECI (Escuela Colombiana de Ingeniería), Laboratorio de Antropometría, Bogotá D.C [8] National University of Singapore - NSU, “Robotic Muscles lift 80 times own material weight, p.1, 2013 [On line]: https://www.sciencedaily.com/releases/2013/09/130903091034.htm [9] Nigel Palastanga, Derek Field, Roger Soames, “Anatomía y movimiento humano Estructura y funcionamiento”, Editorial Paidotribo, 26/04/2007 - 606 páginas [10] Schulte H F, "The characteristics of the McKibben Artificial Muscle", The Application of External Power in Prosthetics and Orthotics, pp 94–115, National Academy of Sciences– National Research Council, Publication 874, Lake Arrowhead, 1961 [11] Tosi R, Análisis de movimiento de la flexión del antebrazo sobre el brazo desde la perspectiva Anátomo Funcional, PubliCE, Volumen 0, 1998 http://www.iaeme.com/IJMET/index.asp 379 Line] editor@iaeme.com [En ... muscle with load and no load in real assembly http://www.iaeme.com/IJMET/index.asp 370 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles Actuator characterization without... account the degrees of freedom that a human arm is able to rotate and / or move http://www.iaeme.com/IJMET/index.asp 372 editor@iaeme.com Prototype of a Human Upper Limb Driven by Pneumatic Muscles. .. own axis The above can be seen in Figure 3 PNEUMATIC MUSCLE An actuator is defined as a mechanical device capable of generating a force to achieve a displacement, the force that causes the actuator