Contraction Of Artificial Muscle Research Articles

Deformable airfoil using hybrid of mixed integration electrolysis and fluids chemical reaction (HEFR) artificial muscle technique

In this research, by inspiration of natural myosin motion in artificial muscle contraction, a new method for changing the thickness of an airfoil has been proposed by hybrid of mixed integration electrolysis module and chemical reaction (HEFR) of sodium bicarbonate (NaHCO3 (s)) and acetic acid (CH3COOH (l)). The mentioned method has the ability to create pressure in the fluid in a short time and fast transfer without delay due to the integration of the method in the fluid transfer tube to soft sealed skin. With soft sealed skin swelling and movement of solid skeletal structure, the force is transmitted to the desired mechanism. First, for a single of soft skin and solid structure, remarkable displacement over time in the various loading condition (by the inflation tester) has been investigated. It is shown that the proposed mechanism is capable of moving 246 g during 3 s with total mechanism weight of 10 g. In the following, the mechanism is developed into a symmetrical rhombus (set of soft skin-solid structure) with the ability to contract and expand to provide variable airfoil thickness. The proposed mechanism has the ability to move in the horizontal and vertical axis (expansion and contraction) in lower than 5 s by applying the HEFR technique. Such a mechanism is mounted on a symmetrical airfoil and has the ability to change the airfoil thickness with the appropriate response time. The proposed mechanism can be used in various industrial applications such as robotics.

Design of Hybrid Phase Sliding Mode Control Scheme for Lower Extremity Exoskeleton

Aiming at a pneumatic artificial muscle (PAM) lower extremity exoskeleton, a control mechanism based on hybrid phase sliding mode control (SMC) is proposed. First of all, the human gait cycle is mainly divided into the swing phase and stance phase, and the lower extremity exoskeleton phase models are established by the Euler–Lagrange method, respectively. Secondly, the lower limb exoskeleton is inevitably affected in the diverse working environment, and the exoskeleton model has nonlinear and strong coupling characteristics, which both increase the control difficulty. In this situations, a robust sliding mode control method is designed based on an Extended State Observer (ESO). Thirdly, the pneumatic muscle takes time to contract and relax, and then the joint input torque cannot jump when the gait phase changes, hence, the smoothing switching of the assistive control scheme is introduced to solve it. The smoothing switching time is detected by a phase detector, and the phase detector is designed by the plantar pressure information. Finally the comparative simulation shows that this control strategy has the advantages of fast time, high control precision and no jump during control torque switching. Pneumatic artificial muscle contraction rate curve shows that the pneumatic muscles’ motion range meets the control requirement of the exoskeleton.

Nuevas tecnologías en neurorrehabilitación aplicadas al tratamiento del paciente con lesión medular

The use of new technologies in neurorehabilitation in patient with spinal cord injuryHuge changes in the treatment protocols for spinal cord injury patients are taking place thanks to the incorporation of new technologies in neurorehabilitation. Rehabilitation robotic allows high intensity treatments (many repetitions and task-oriented) in motivating environment and providing objective information on patient execution. Both upper and lower extremities may be rehabilitated. Patient in a wheelchair can wander thanks to portable exoskeletons. Brain electrical signals are recorded by electroencephalogram (EEG) or implanted electrodes enabling communication functions, environmental control and the functioning of wheelchair or neuroprosthesis. Functional electrical stimulation is the application of electrical current to muscular tissue resulting in artificial muscle contraction. The most used exoskeleton robots are those with hand opening and closing mechanism and with assisted walking device. Virtual reality creates an interface for the human-computer interaction enabling immersion in virtual environments. All those technologies are motivational tools facilitating treatment adherence.

Design studies on cellular structures with pneumatic artificial muscle inclusions for modulus variation

This article presents a variable modulus cellular structure based on a hexagonal unit cell with pneumatic artificial muscle inclusions. The cell is pin-jointed, loaded in the horizontal direction, with three pneumatic artificial muscles (one vertical pneumatic artificial muscle and two horizontal pneumatic artificial muscles) oriented in an “H” configuration between the vertices of the cell. A method for calculation of the hexagonal cell modulus is introduced, as is an expression for the balance of tensile forces between the horizontal and vertical pneumatic artificial muscles. Simulation is then compared to experimental measurement of the unit cell modulus in the horizontal direction over a pressure range of 682 kPa, and an increase in cell modulus of 200% is demonstrated experimentally. A design study considering parametric variation in cell angle, vertical to inclined wall length ratio, and pneumatic artificial muscle contraction ratios shows that changes in modulus of over 1000% are possible when the pneumatic artificial muscles are pressurized to 1992 kPa. This concept provides a way to create a structural unit cell whose in-plane modulus can be tuned based on the orientation of pneumatic artificial muscles within the cell and the pressure supplied to the individual muscles.

Healing-on-demand composites based on polymer artificial muscle

In this study, a new polymer artificial muscle based healing-on-demand composite was prepared and characterized. The composite consists of polymer artificial muscle made of commercial fishing line, thermoset host, and thermoplastic particle. Three-point bending damage to the beam sample can be healed even at a constrained boundary condition upon local heating, undergoing a close-then-heal procedure. The fractured beams were heated locally by a heat gun for 10 min. The healing efficiency was investigated at both free boundary condition and fixed boundary condition. The fast contraction of artificial muscle brings the fractured surfaces in spatial proximity; simultaneously, the melting thermoplastic agent fills the crack via capillary action and bonds the two fracture surfaces. With 60% prestrain of the reinforcing polymer artificial muscles (8% volume fraction), over 60% of healing efficiency was achieved at free boundary condition and 54% at fixed boundary condition after repeated damage-healing events. Due to its low cost, high healing efficiency, good compatibility, and excellent flexibility, we envision that the polymer artificial muscle will be a new device in designing next generation healing-on-demand polymer composite.

Robust and Accurate Closed-Loop Control of McKibben Artificial Muscle Contraction with a Linear Single Integral Action

We analyze the possibility of taking advantage of artificial muscle’s own stiffness and damping, and substituting it for a classic proportional-integral-derivative controller (PID) controller an I controller. The advantages are that there would only be one parameter to tune and no need for a dynamic model. A stability analysis is proposed from a simple phenomenological artificial muscle model. Step and sinus-wave tracking responses performed with pneumatic McKibben muscles are reported showing the practical efficiency of the method to combine accuracy and load robustness. In the particular case of the McKibben artificial muscle technology, we suggest that the dynamic performances in stability and load robustness would result from the textile nature of its braided sleeve and its internal friction which do not obey Coulomb’s third law, as verified by preliminary reported original friction experiments. Comparisons are reported between three kinds of braided sleeves made of rayon yarns, plastic, and thin metal wires, whose similar closed-loop dynamic performances are highlighted. It is also experimentally shown that a sleeve braided with thin metal wires can give high accuracy performance, in step as in tracking response. This would be due to a low static friction coefficient combined with a kinetic friction exponentially increasing with speed in accordance with hydrodynamic lubrication theory applied to textile physics.

2A1-D10 力学平衡モデルを使用したラバーレス人工筋肉駆動1リンクマニピュレータの角度制御(アクチュエータの機構と制御(1))

We are developing the Rubberless artificial muscle to improve problems by the deterioration of the rubber tube of the rubber artificial muscle. The Rubberless artificial muscle can be driven by low pressure than rubber artificial muscle. However, Rubberless artificial muscle's contraction characteristic is highly nonlinear and it has large hysteresis characteristics. Hence, it is difficult to control the artificial muscle manipulator. This paper describes about mechanical equilibrium model of Rubberless artificial muscle and angle control of Rubberless artificial muscle manipulator. As a result, the delay with the targeted value occurred, but an almost good result was provided. Therefore, I confirmed possibility of the application to mechatronics of Rubberless artificial muscle.

The Effect of Electrical Stimulation of the Calf Muscle and Compression Stocking on Venous Blood Flow Velocity

Neuromuscular electrical stimulation (NMES) refers to the application of current pulses, through surface or implanted electrodes to trigger generation of a neural action potential train to produce artificial muscle contraction in the associated muscle. In surface NMES pre-gelled electrodes are placed on the skin surface over the motor point of the muscle of interest, and is a completely non-invasive technique. Graduated compression stockings (GCS) and bandaging facilitate venous return initiated by a physiological calf-muscle contraction. We hypothesised that an NMES-elicited artificial calf muscle contraction would augment venous return from the lower limbs and that the use of NMES in conjunction with a GCS would result in increased augmentation. The aims of this study were: