An effective and rapid response of muscle contraction and relaxation is crucial for performing appropriate body gaits,including movements of the arms and legs.Any deformation in the muscles can disrupt gait stability,...An effective and rapid response of muscle contraction and relaxation is crucial for performing appropriate body gaits,including movements of the arms and legs.Any deformation in the muscles can disrupt gait stability,making muscle movement difficult.The arm,consisting of the radius,ulna,and humerus,can be modeled as mechanically jointed pendulums,with tensions from the arm muscles varying during contraction and relaxation.In a static state,the muscles maintain constant tension and length,even when external gravitational force is applied to the hand.This study presents a system in which a pair of jointed pendulums is driven by artificial muscles,represented by flexible ropes wound around the edge of an electronic motor's wheel.Muscle movement is simulated through the adjustment of the length of the flexible ropes attached to the motor.Switching between the clockwise and counterclockwise rotation of the motor modifies the length of the flexible ropes,thereby altering the intrinsic tensions to control arm movements.Electrical signals from a simple neural circuit are used to control the rotation of the electronic motor,enabling the regulation of muscle movement in the arm model by adjustable flexible ropes.The stability criterion for the electromechanical arm is derived,and the interactions among the neural circuit,electronic motor,and jointed pendulums are examined in detail.The results and proposed scheme can contribute to the design of controllable artificial arms,providing potential assistance to disabled arms by incorporating auxiliary artificial muscles.展开更多
The twisted and coiled polymer(TCP)artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power density.The relation between geometry,mechanics,and actuation performance for this kind of ...The twisted and coiled polymer(TCP)artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power density.The relation between geometry,mechanics,and actuation performance for this kind of muscle is crucial.In this study,we study the mechanics and actuation characteristics of TCP tube-based muscles driven by hydraulic pressure through experiment,theory,and finite element simulation.Accounting for the helical geometry and transverse isotropy of the TCP muscles,we develop a phenomenological model to predict the actuation performance of TCP tube-based muscles.The torsional and tensile actuation characteristics of the twisted and TCP tube-based muscle driven by hydraulic pressure are characterized.It is found that the cold drawing enhances the anisotropy of the polyvinyl chloride tube,resulting in an improved actuation performance of the twisted and TCP muscles.The torsional actuation in the twisted tube reaches the maximum at a critical bias angle for a given pressure,while the tensile actuation in TCP muscles increases with the coil diameter.The theoretical predictions and simulations are in good agreement with experimental results.This study is significant for guiding the design of TCP tube-based muscles and achieving their precise actuation control.展开更多
Force feedback dataglove is an important interface of human-machine interaction between manipulator and virtual assembly system, which is in charge of the bidirectional transmission of movement and force information b...Force feedback dataglove is an important interface of human-machine interaction between manipulator and virtual assembly system, which is in charge of the bidirectional transmission of movement and force information between computer and operator. The exoskeleton force feedback dataglove is designed taking the pneumatic artificial muscle as actuator, meanwhile, its structure and work principle are introduced, and the force control problem is analyzed and researched by experiment. The mathematic model of grasping rigid object for finger is established. Considering the friction of tendon-sheath system and finger deformation, the closed-loop force control for a single joint, a single finger and multi-fingers are studied respectively by the feedforward proportional-integral（PI） control method with variable arguments. On the premise of the force smoothness, the control error of the force exerted on the finger joint is in the range of ±0.25 N, which meets the requirement of force feedback. By experimental analysis, the reason of force fluctuation is that the finger joint has a small amplitude quiver, and the consistent change tendency of the force between proximal interphalangeal（PIP） joint and distal interphalangeal（DIP） joint results from their angle coupling relationship.展开更多
According to the deficiency of the present model of pneumatic artificialmuscles (PAM), a serial model is built up based on the PAM's essential working principle with theelastic theory, it is validated by the quasi...According to the deficiency of the present model of pneumatic artificialmuscles (PAM), a serial model is built up based on the PAM's essential working principle with theelastic theory, it is validated by the quasi-static and dynamic experiment results, which are gainedfrom two experiment systems. The experiment results and the simulation results illustrate that theserial model has made a great success compared with Chou's model, which can describe the forcecharacteristics of PAM more precisely. A compensation item considering the braid's elasticity andthe coulomb damp is attached to the serial model based on the analysis of the experiment results.The dynamic experiment proves that the viscous damp of the PAM could be ignored in order to simplifythe model of PAM. Finally, an improved serial model of PAM is obtained.展开更多
An exoskeleton force feedback dataglove is developed, which uses the pneumatic artificial muscles as actuators. On the basis of the simplified hand model, the motion equation is deduced according to the theory of Dena...An exoskeleton force feedback dataglove is developed, which uses the pneumatic artificial muscles as actuators. On the basis of the simplified hand model, the motion equation is deduced according to the theory of Denavit-Hartenberg. The model of the equivalent contact forces exerted by the object on the finger is proposed. By the principle of virtual work, the static equilibrium of finger is established. The force Jacobian matrix of finger is calculated, and then the joint torques of the finger when grasping objects are obtained. The theory and structure of the force feedback datagolve are introduced. Based on the theory of motion stabilization of four-bar linkage, the flexion angles of joints are measured. The torques on finger joints caused by the output forces of pneumatic artificial muscles are calculated. The output forces of pneumatic artificial muscle, whose values are controlled by its inner pressure, can be calculated by the joint torques of the finger when grasping objects. The arms of force, driving torques and the needed output forces of pneumatic muscle are calculated for each joint of the index finger. The criterion of output force of pneumatic muscle is given.展开更多
In this paper, the practicality and feasibility of Active Force Control （AFC） integrated with Fuzzy Logic（AFCAFL） applied to a two link planar arm actuated by a pair of Pneumatic Artificial Muscle （PAM） is inves...In this paper, the practicality and feasibility of Active Force Control （AFC） integrated with Fuzzy Logic（AFCAFL） applied to a two link planar arm actuated by a pair of Pneumatic Artificial Muscle （PAM） is investigated. The study emphasizes on the application and control of PAM actuators which may be considered as the new generation of actuators comprising fluidic muscle that has high-tension force, high power to weight ratio and high strength in spite of its drawbacks in the form of high nonlinearity behaviour, high hysteresis and time varying parameters. Fuzzy Logic （FL） is used as a technique to estimate the best value of the inertia matrix of robot arm essential for the AFC mechanism that is complemented with a conventional Propor- tional-Integral-Derivative （PID） control at the outermost loop. A simulation study was first performed followed by an experi- mental investigation for validation. The experimental study was based on the independent joint tracking control and coordinated motion control of the arm in Cartesian or task space. In the former, the PAM actuated arm is commanded to track the prescribed trajectories due to harmonic excitations at the joints for a given frequency, whereas for the latter, two sets of trajectories with different loadings were considered. A practical rig utilizing a Hardware-In-The-Loop Simulation （HILS） configuration was developed and a number of experiments were carried out. The results of the experiment and the simulation works were in good agreement, which verified the effectiveness and robustness of the proposed AFCAFL scheme actuated by PAM.展开更多
A variable camber wing driven by pneumatic artificial muscles is developed in this paper. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed and the relations...A variable camber wing driven by pneumatic artificial muscles is developed in this paper. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed and the relationship between the static output force and the air pressure is investigated. Experimental results show that the static output force of pneumatic artificial muscle decreases nonlinearly with the increase of contraction ratio. Secondly, the model of variable camber wing driven by pneumatic artificial muscles is manufactured to validate the variable camber concept. Finally, wind tunnel tests are conducted in the low speed wind tunnel. It is found that the wing camber increases with the increase of air pressure. When the air pressure of PAMs is 0.4 MPa and 0.5 MPa, the tip displacement of the trailing-edge is 3 mm and 5 mm, respectively. The lift of aerofoil with flexible trailing-edge increases by 87% at AOA of 5°.展开更多
Dielectric elastomer actuators (DEAs) artificial muscle is a typical interdisciplinary research category, which has developed by leaps and bounds in the past 20 years, showing great application prospects in various fi...Dielectric elastomer actuators (DEAs) artificial muscle is a typical interdisciplinary research category, which has developed by leaps and bounds in the past 20 years, showing great application prospects in various fields. Upon external electrical stimulation, dielectric elastomers (DEs) display large deformation, high energy density and fast response, affording a promising material candidate for soft robotics. Herein, the working mechanisms, commonly used materials as well as the concepts for improving the performance of DEA materials are introduced. Various DEA driven soft robots, including soft grippers, bioinspired artificial arms, crawling/walking/underwater/flying/jumping soft robots and tunable lenses, are then described in detail. Finally, the main challenges of DEA driven soft robots are summarized, and some perspectives for promoting the practical application of DEAs are also proposed.展开更多
The pneumatic artificial muscles are widely used in the fields of medicalrobots, etc. Neural networks are applied to modeling and controlling of artificial muscle system. Asingle-joint artificial muscle test system is...The pneumatic artificial muscles are widely used in the fields of medicalrobots, etc. Neural networks are applied to modeling and controlling of artificial muscle system. Asingle-joint artificial muscle test system is designed. The recursive prediction error (RPE)algorithm which yields faster convergence than back propagation (BP) algorithm is applied to trainthe neural networks. The realization of RPE algorithm is given. The difference of modeling ofartificial muscles using neural networks with different input nodes and different hidden layer nodesis discussed. On this basis the nonlinear control scheme using neural networks for artificialmuscle system has been introduced. The experimental results show that the nonlinear control schemeyields faster response and higher control accuracy than the traditional linear control scheme.展开更多
The bionic legs are generally driven by motors which have the disadvantages of large size and heavy weight.In contrast,the bionic legs driven by pneumatic artificial muscles(PAMs)have the advantages of light weight,go...The bionic legs are generally driven by motors which have the disadvantages of large size and heavy weight.In contrast,the bionic legs driven by pneumatic artificial muscles(PAMs)have the advantages of light weight,good bionics and flexibility.A kind of bionic leg driven by PAMs is designed.The proportional-integral-derivative(PID)algorithm and radial basis function neural network(RBFNN)algorithm are combined to design RBFNN-PID controller,and a low-pass filter is added to the control system,which can effectively improve the jitter phenomenon of the joint during the experiment.It is verified by simulation that the RBFNN-PID algorithm is better than traditional PID algorithm,the response time of joint is improved from 0.15 s to 0.07 s,and the precision of joint position control is improved from 0.75°to 0.001°.The experimental results show that the amplitude of the change in error is reduced from 0.5°to 0.2°.It is verified by jumping experiment that the mechanism can realize jumping action under control,and can achieve the horizontal displacement of 500 mm and the vertical displacement of 250 mm.展开更多
For promising applications such as soft robotics,flexible haptic monitors,and active biomedical devices,it is important to develop ultralow voltage,highly-performant artificial muscles with high bending strains,rapid ...For promising applications such as soft robotics,flexible haptic monitors,and active biomedical devices,it is important to develop ultralow voltage,highly-performant artificial muscles with high bending strains,rapid response times,and superior actuation endurance.We report a novel highly performant and low-cost artificial muscle based on microfibrillated cellulose(MFC),ionic liquid(IL),and polyvinyl alcohol(PVA),The proposed MFC-IL-PVA actuator exhibits excellent electro-chemical performance and actuations characteristics with a high specific capacitance of 225 mF/cm2,a large bending strain of 0.51%,peak displacement up to 7.02 mm at 0.25 V ultra-low voltage,outstanding actuation flexural endurance(99.1%holding rate for 3 h),and a wide frequency band(0.1-5 Hz).These attributes stem mainly from its high specific surface area and porosity,tunable mechanical properties,and the strong ionic interactions of cations and anions with MFC and PVA in ionic liquids.Furthermore,bionic applications such as bionic flytraps,bionic butterflies with vibrating wings,and smart circuit switches have been successfully realized using this technology.These specific bionic applications demonstrate the versatility and potential of the MFC-IL-PVA actuator,highlighting its important role in the fields of bionic engineering,robotics,and smart materials.They open up new possibilities for innovative scientific research and technological applications.展开更多
This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,na...This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,namely the Internal Torsion Spring Compliant Actuator(ICA)and the External Spring Compliant Actuator(ECA),and present a comparative analysis against the previously conceived Magnet Integrated Soft Actuator(MISA)through computational and experimental results.These actuators,employing a motor-tendon system,emulate biological muscle-like forms,enhancing artificial muscle technology.Then,applications of the proposed actuators in a robotic arm inspired by the human musculoskeletal system are presented.Experiments demonstrate satisfactory power in tasks like lifting dumbbells(peak power:36 W),playing table tennis(end-effector speed:3.2 m/s),and door opening,without compromising biomimetic aesthetics.Compared to other linear stiffness serial elastic actuators(SEAs),ECA and ICA exhibit high power-to-volume(361×10^(3)W/m^(3))and power-to-mass(111.6 W/kg)ratios respectively,endorsing the biomimetic design’s promise in robotic development.展开更多
Flying insects are capable of flapping their wings to provide the required power and control forces for flight.A coordinated organizational system including muscles,wings,and control architecture plays a significant r...Flying insects are capable of flapping their wings to provide the required power and control forces for flight.A coordinated organizational system including muscles,wings,and control architecture plays a significant role,which provides the sources of inspiration for designing flapping-wing vehicles.In recent years,due to the development of micro-and meso-scale manufacturing technologies,advances in components technologies have directly led to a progress of smaller Flapping-Wing Nano Air Vehicles(FWNAVs)around gram and sub-gram scales,and these air vehicles have gradually acquired insect-like locomotive strategies and capabilities.This paper will present a selective review of components technologies for ultra-lightweight flapping-wing nano air vehicles under 3 g,which covers the novel propulsion methods such as artificial muscles,flight control mechanisms,and the design paradigms of the insect-inspired wings,with a special focus on the development of the driving technologies based on artificial muscles and the progress of the biomimetic wings.The challenges involved in constructing such small flapping-wing air vehicles and recommendations for several possible future directions in terms of component technology enhancements and overall vehicle performance are also discussed in this paper.This review will provide the essential guidelines and the insights for designing a flapping-wing nano air vehicle with higher performance.展开更多
Thermo-responsive shape memory hydrogels generally achieve shape fixation at low temperatures,and shape recovery at high temperatures.However,these hydrogels usually suffer from poor mechanical properties.Herein,we pr...Thermo-responsive shape memory hydrogels generally achieve shape fixation at low temperatures,and shape recovery at high temperatures.However,these hydrogels usually suffer from poor mechanical properties.Herein,we present a unique poly(acrylic acid)/calcium acetate shape memory hydrogel with cold-induced shape recovery performances as ultrastrong artificial muscles.Since the acetate groups could form aggregate at high temperatures and thus induce the association of the hydrogel network,the hydrogel can be fixed into a temporary shape upon heating and recover to its original shape in a cold environment.Moreover,a programmable shape recovery process is realized by adjusting the shape fixing time.In addition,the unique shape memory process enables the application demonstration as bio-inspired artificial muscles with an ultrahigh work density of45.2 kJ m^(-3),higher than that of biological muscles(~8 kJ m^(-3)).展开更多
High-performance yarn artificial muscles are highly desirable as miniature actuators,sensors,energy harvesters,and soft robotics.However,achieving a yarn artificial muscle that covers all the properties of excellent a...High-performance yarn artificial muscles are highly desirable as miniature actuators,sensors,energy harvesters,and soft robotics.However,achieving a yarn artificial muscle that covers all the properties of excellent actuation performance,mechanical robustness,structural stability,and high scalability by a low-cost strategy is still a great challenge.Herein,a bio-inspired fasciated yarn structure is first reported for creating robust high-performance yarn artificial muscles.Unlike conventional strategies that leverage costly materials or complex processing,the developed yarn artificial muscles are constructed by hierarchically helical and sheath-core assembly design of cost-effective common fibers,such as viscose and polyester.The hierarchically helical sheath structure pushes the theoretical limit of the inserted twist in yarns and endows the yarn muscles with large stroke(5815°cm^(-1))and high work capacity(23.5 J kg^(-1)).Due to the rapid water transfer and efficient energy conversion of inter-sheath-core coupling,the as-prepared yarn muscles possess fast response,high rotation accelerated speed,and low recovery hysteresis.Moreover,the inactive core yarn serves as support for internal tethering and load-bearing,enabling these yarn muscles to maintain a self-stable structure,robust life cycle and mechanics.We show that the yarn muscle fabricated in this method is readily available and highly scalable for achieving high-dimensional actuation deformations,which considerably broadens the application scenarios of artificial muscles.展开更多
This paper presents a method for the length-pressure hysteresis modeling of pneumatic artificial muscles(PAMs)by using a modified generalized Prandtl-Ishlinskii(GPI)model.Different from the approaches for establishing...This paper presents a method for the length-pressure hysteresis modeling of pneumatic artificial muscles(PAMs)by using a modified generalized Prandtl-Ishlinskii(GPI)model.Different from the approaches for establishing the GPI models by replacing the linear envelope functions of operators with hyperbolic tangent and exponential envelop functions,the proposed model is derived by modifying the envelope functions of operators into arc tangent functions,which shows an improvement in the modeling accuracy.The effectiveness of the proposed model is verified by the experimental data of a PAM.Furthermore,its capacity in capturing the hysteresis relationship between length and pressure is testified by giving different input pressure signals.With regard to the computational efficiency,the influence of the number of operators on the modeling accuracy is discussed.Furthermore,the inversion of the GPI model is derived.Its capability of compensating the hysteresis nonlinearities is confirmed via the simulation and experimental study.展开更多
Recently,researches on artificial muscles for imitating the functions of the natural muscles has attracted wide attention.The fiber-shape actuators,shape-memory materials or deforming devices,which are similar to huma...Recently,researches on artificial muscles for imitating the functions of the natural muscles has attracted wide attention.The fiber-shape actuators,shape-memory materials or deforming devices,which are similar to human muscle fiber bundles,have extensively studied and provided more possibilities for artificial muscles.Herein,we develop a thermal responsible fiber-shaped actuator based on the low-cost hollow polyethylene fiber.The sheath-core structured fibrous actuators and the stainless-steel conductive yarn winded pre-stretched polyethylene actuators are fabricated with the heating assisted pre-stretching procedure.The actuation mechanism of the thermal-responsive orientation change of molecular chains driving the actuation is discussed and demonstrated by 2D XRD patterns.These polyethylene-based fibrous actuators displayed three significant advantages including(i)color-turning and shape-changing bifunctional response,(ii)direct joule heating actuation and(iii)effective contraction(18%shrinkage of the pristine length)and lifting ability(the ratio of lifting weight to self-weight is up to 50).展开更多
Developing artificial muscles that can replace biological muscles to accomplish various tasks iswhat we have long been aiming for.Recent advances in flexible materials and 3D printing technology greatly promote the de...Developing artificial muscles that can replace biological muscles to accomplish various tasks iswhat we have long been aiming for.Recent advances in flexible materials and 3D printing technology greatly promote the development of artificial muscle technology.A variety of flexible material-based artificial muscles that are driven by different external stimuli,including pressure,voltage,light,magnetism,temperature,etc.,have been developed.Among these,fluid-driven artificial muscles(FAMs),which can convert the power of fluid(gas or liquid)into the force output and displacement of flexible materials,are the most widely used actuation methods for industrial robots,medical instruments,and human-assisted devices due to their simplicity,excellent safety,large actuation force,high energy efficiency,and low cost.Herein,the bio-design,manufacturing,sensing,control,and applications of FAMs are introduced,including conventional pneumatic/hydraulic artificial muscles and several innovative artificial muscles driven by functional fluids.What’s more,the challenges and future directions of FAMs are discussed.展开更多
Recently,researchers have concentrated on studying ionic polymer metal composite(IPMC)artificial muscle,which has numerous advantages including a relatively large strain under low input voltage,flexibility,high respon...Recently,researchers have concentrated on studying ionic polymer metal composite(IPMC)artificial muscle,which has numerous advantages including a relatively large strain under low input voltage,flexibility,high response,low noise,light weight,and high driving energy density.This paper reports recent developments in IPMC artificial muscle,including improvement methods,modeling,and applications.Different types of IPMCs are described,along with various methods for overcoming some shortcomings,including improvement of Nafion matrix membranes,surface preparation of Nafion membranes,the choice of high-performing electrodes,and new electro-active polymers for enhancing the properties of IPMCs.IPMC models are also reviewed,providing theoretical guidance for studying the performance and applications of IPMCs.Successful applications such as bio-inspired robots,opto-mechatronic systems,and medical engineering are discussed.展开更多
Today the developed yarn muscles or actuators still cannot satisfy the requirements of working in high-temperature environ-ments.Thermal resistivity is highly needed in aerospace and industrial protection applications...Today the developed yarn muscles or actuators still cannot satisfy the requirements of working in high-temperature environ-ments.Thermal resistivity is highly needed in aerospace and industrial protection applications.Herein,an artificial muscle with high-temperature tolerance is prepared using carbon nanotube(CNT)wrapped poly(p-phenylene benzobisoxazole)(PBO)composite yarns.A thermal twisting method was utilized to reorientate the stiff PBO molecular chains into a uniform and twist-stable coiled structure.The CNT/PBO composite yarn muscle generates reversible contractile strokes up to 18.9%under 5.4 MPa tension and outputs 1.3 kJ kg^(-1) energy density.In contrast to previous actuators,which are normally oper-ated at room temperatures,the CNT/PBO composite yarn muscles can work at ambient temperatures up to 300℃ with high contractile stroke and long-term stability.A bionic inchworm robot,a deployable structure,and smart textiles driven by the high-temperature-tolerant yarn muscles were demonstrated,showing the promise as a soft actuator towards high-temperature environment applications.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62361037,12072139)。
文摘An effective and rapid response of muscle contraction and relaxation is crucial for performing appropriate body gaits,including movements of the arms and legs.Any deformation in the muscles can disrupt gait stability,making muscle movement difficult.The arm,consisting of the radius,ulna,and humerus,can be modeled as mechanically jointed pendulums,with tensions from the arm muscles varying during contraction and relaxation.In a static state,the muscles maintain constant tension and length,even when external gravitational force is applied to the hand.This study presents a system in which a pair of jointed pendulums is driven by artificial muscles,represented by flexible ropes wound around the edge of an electronic motor's wheel.Muscle movement is simulated through the adjustment of the length of the flexible ropes attached to the motor.Switching between the clockwise and counterclockwise rotation of the motor modifies the length of the flexible ropes,thereby altering the intrinsic tensions to control arm movements.Electrical signals from a simple neural circuit are used to control the rotation of the electronic motor,enabling the regulation of muscle movement in the arm model by adjustable flexible ropes.The stability criterion for the electromechanical arm is derived,and the interactions among the neural circuit,electronic motor,and jointed pendulums are examined in detail.The results and proposed scheme can contribute to the design of controllable artificial arms,providing potential assistance to disabled arms by incorporating auxiliary artificial muscles.
基金supported by the National Natural Science Foundation of China(Grant No.12272146)the Fundamental Research Funds for the Central Universities(Grant No.2024BRA009)the National Ten Thousand Talent Program for Young Top-notch Talents。
文摘The twisted and coiled polymer(TCP)artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power density.The relation between geometry,mechanics,and actuation performance for this kind of muscle is crucial.In this study,we study the mechanics and actuation characteristics of TCP tube-based muscles driven by hydraulic pressure through experiment,theory,and finite element simulation.Accounting for the helical geometry and transverse isotropy of the TCP muscles,we develop a phenomenological model to predict the actuation performance of TCP tube-based muscles.The torsional and tensile actuation characteristics of the twisted and TCP tube-based muscle driven by hydraulic pressure are characterized.It is found that the cold drawing enhances the anisotropy of the polyvinyl chloride tube,resulting in an improved actuation performance of the twisted and TCP muscles.The torsional actuation in the twisted tube reaches the maximum at a critical bias angle for a given pressure,while the tensile actuation in TCP muscles increases with the coil diameter.The theoretical predictions and simulations are in good agreement with experimental results.This study is significant for guiding the design of TCP tube-based muscles and achieving their precise actuation control.
基金supported by National Natural Science Foundation of China (Grant No. 50375034)Research Foundation for the Doctoral Program of Higher Education of China (Grant No. 200802881002)
文摘Force feedback dataglove is an important interface of human-machine interaction between manipulator and virtual assembly system, which is in charge of the bidirectional transmission of movement and force information between computer and operator. The exoskeleton force feedback dataglove is designed taking the pneumatic artificial muscle as actuator, meanwhile, its structure and work principle are introduced, and the force control problem is analyzed and researched by experiment. The mathematic model of grasping rigid object for finger is established. Considering the friction of tendon-sheath system and finger deformation, the closed-loop force control for a single joint, a single finger and multi-fingers are studied respectively by the feedforward proportional-integral（PI） control method with variable arguments. On the premise of the force smoothness, the control error of the force exerted on the finger joint is in the range of ±0.25 N, which meets the requirement of force feedback. By experimental analysis, the reason of force fluctuation is that the finger joint has a small amplitude quiver, and the consistent change tendency of the force between proximal interphalangeal（PIP） joint and distal interphalangeal（DIP） joint results from their angle coupling relationship.
文摘According to the deficiency of the present model of pneumatic artificialmuscles (PAM), a serial model is built up based on the PAM's essential working principle with theelastic theory, it is validated by the quasi-static and dynamic experiment results, which are gainedfrom two experiment systems. The experiment results and the simulation results illustrate that theserial model has made a great success compared with Chou's model, which can describe the forcecharacteristics of PAM more precisely. A compensation item considering the braid's elasticity andthe coulomb damp is attached to the serial model based on the analysis of the experiment results.The dynamic experiment proves that the viscous damp of the PAM could be ignored in order to simplifythe model of PAM. Finally, an improved serial model of PAM is obtained.
基金This project is supported by National Natural Science Foundation of China(No.50375034).
文摘An exoskeleton force feedback dataglove is developed, which uses the pneumatic artificial muscles as actuators. On the basis of the simplified hand model, the motion equation is deduced according to the theory of Denavit-Hartenberg. The model of the equivalent contact forces exerted by the object on the finger is proposed. By the principle of virtual work, the static equilibrium of finger is established. The force Jacobian matrix of finger is calculated, and then the joint torques of the finger when grasping objects are obtained. The theory and structure of the force feedback datagolve are introduced. Based on the theory of motion stabilization of four-bar linkage, the flexion angles of joints are measured. The torques on finger joints caused by the output forces of pneumatic artificial muscles are calculated. The output forces of pneumatic artificial muscle, whose values are controlled by its inner pressure, can be calculated by the joint torques of the finger when grasping objects. The arms of force, driving torques and the needed output forces of pneumatic muscle are calculated for each joint of the index finger. The criterion of output force of pneumatic muscle is given.
文摘In this paper, the practicality and feasibility of Active Force Control （AFC） integrated with Fuzzy Logic（AFCAFL） applied to a two link planar arm actuated by a pair of Pneumatic Artificial Muscle （PAM） is investigated. The study emphasizes on the application and control of PAM actuators which may be considered as the new generation of actuators comprising fluidic muscle that has high-tension force, high power to weight ratio and high strength in spite of its drawbacks in the form of high nonlinearity behaviour, high hysteresis and time varying parameters. Fuzzy Logic （FL） is used as a technique to estimate the best value of the inertia matrix of robot arm essential for the AFC mechanism that is complemented with a conventional Propor- tional-Integral-Derivative （PID） control at the outermost loop. A simulation study was first performed followed by an experi- mental investigation for validation. The experimental study was based on the independent joint tracking control and coordinated motion control of the arm in Cartesian or task space. In the former, the PAM actuated arm is commanded to track the prescribed trajectories due to harmonic excitations at the joints for a given frequency, whereas for the latter, two sets of trajectories with different loadings were considered. A practical rig utilizing a Hardware-In-The-Loop Simulation （HILS） configuration was developed and a number of experiments were carried out. The results of the experiment and the simulation works were in good agreement, which verified the effectiveness and robustness of the proposed AFCAFL scheme actuated by PAM.
基金Sponsored by the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20102302120032)the Open Foundation of Key Laboratory of Advanced Composites in Special Environmentsthe Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(Grant No.HIT.NSRIF.2012028)
文摘A variable camber wing driven by pneumatic artificial muscles is developed in this paper. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed and the relationship between the static output force and the air pressure is investigated. Experimental results show that the static output force of pneumatic artificial muscle decreases nonlinearly with the increase of contraction ratio. Secondly, the model of variable camber wing driven by pneumatic artificial muscles is manufactured to validate the variable camber concept. Finally, wind tunnel tests are conducted in the low speed wind tunnel. It is found that the wing camber increases with the increase of air pressure. When the air pressure of PAMs is 0.4 MPa and 0.5 MPa, the tip displacement of the trailing-edge is 3 mm and 5 mm, respectively. The lift of aerofoil with flexible trailing-edge increases by 87% at AOA of 5°.
基金support from the National Natural Science Foundation of China(Grant No.51525301)the Talent Cultivation of State Key Laboratory of Organic-Inorganic Composites(No.OIC-D2021002).
文摘Dielectric elastomer actuators (DEAs) artificial muscle is a typical interdisciplinary research category, which has developed by leaps and bounds in the past 20 years, showing great application prospects in various fields. Upon external electrical stimulation, dielectric elastomers (DEs) display large deformation, high energy density and fast response, affording a promising material candidate for soft robotics. Herein, the working mechanisms, commonly used materials as well as the concepts for improving the performance of DEA materials are introduced. Various DEA driven soft robots, including soft grippers, bioinspired artificial arms, crawling/walking/underwater/flying/jumping soft robots and tunable lenses, are then described in detail. Finally, the main challenges of DEA driven soft robots are summarized, and some perspectives for promoting the practical application of DEAs are also proposed.
基金This project is supported by Foundation of Public Laboratory on Robotics of Chinese Academy of Sciences.
文摘The pneumatic artificial muscles are widely used in the fields of medicalrobots, etc. Neural networks are applied to modeling and controlling of artificial muscle system. Asingle-joint artificial muscle test system is designed. The recursive prediction error (RPE)algorithm which yields faster convergence than back propagation (BP) algorithm is applied to trainthe neural networks. The realization of RPE algorithm is given. The difference of modeling ofartificial muscles using neural networks with different input nodes and different hidden layer nodesis discussed. On this basis the nonlinear control scheme using neural networks for artificialmuscle system has been introduced. The experimental results show that the nonlinear control schemeyields faster response and higher control accuracy than the traditional linear control scheme.
基金Supported by the National Natural Science Foundation of China(No.51775323).
文摘The bionic legs are generally driven by motors which have the disadvantages of large size and heavy weight.In contrast,the bionic legs driven by pneumatic artificial muscles(PAMs)have the advantages of light weight,good bionics and flexibility.A kind of bionic leg driven by PAMs is designed.The proportional-integral-derivative(PID)algorithm and radial basis function neural network(RBFNN)algorithm are combined to design RBFNN-PID controller,and a low-pass filter is added to the control system,which can effectively improve the jitter phenomenon of the joint during the experiment.It is verified by simulation that the RBFNN-PID algorithm is better than traditional PID algorithm,the response time of joint is improved from 0.15 s to 0.07 s,and the precision of joint position control is improved from 0.75°to 0.001°.The experimental results show that the amplitude of the change in error is reduced from 0.5°to 0.2°.It is verified by jumping experiment that the mechanism can realize jumping action under control,and can achieve the horizontal displacement of 500 mm and the vertical displacement of 250 mm.
基金supported by National Natural Science Foundation of China(51525504,51905487,12102393)Bellwethers Research and Development Plan of Zhejiang Province of China(Grant No.2023C01045)+2 种基金Fundamental Research Funds of Zhejiang Sci-Tech University(24242115-Y)Natural Science Foundation of Zhejiang Province(LY21E050023)Zhejiang Provincial General Scientific Research Projects Fund of China under Grant Y202353093.
文摘For promising applications such as soft robotics,flexible haptic monitors,and active biomedical devices,it is important to develop ultralow voltage,highly-performant artificial muscles with high bending strains,rapid response times,and superior actuation endurance.We report a novel highly performant and low-cost artificial muscle based on microfibrillated cellulose(MFC),ionic liquid(IL),and polyvinyl alcohol(PVA),The proposed MFC-IL-PVA actuator exhibits excellent electro-chemical performance and actuations characteristics with a high specific capacitance of 225 mF/cm2,a large bending strain of 0.51%,peak displacement up to 7.02 mm at 0.25 V ultra-low voltage,outstanding actuation flexural endurance(99.1%holding rate for 3 h),and a wide frequency band(0.1-5 Hz).These attributes stem mainly from its high specific surface area and porosity,tunable mechanical properties,and the strong ionic interactions of cations and anions with MFC and PVA in ionic liquids.Furthermore,bionic applications such as bionic flytraps,bionic butterflies with vibrating wings,and smart circuit switches have been successfully realized using this technology.These specific bionic applications demonstrate the versatility and potential of the MFC-IL-PVA actuator,highlighting its important role in the fields of bionic engineering,robotics,and smart materials.They open up new possibilities for innovative scientific research and technological applications.
基金research project funded by the National Natural Science Foundation of China(NSFC)under Grant 91948302 and Grant 52021003Research England fund at NERIC.
文摘This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,namely the Internal Torsion Spring Compliant Actuator(ICA)and the External Spring Compliant Actuator(ECA),and present a comparative analysis against the previously conceived Magnet Integrated Soft Actuator(MISA)through computational and experimental results.These actuators,employing a motor-tendon system,emulate biological muscle-like forms,enhancing artificial muscle technology.Then,applications of the proposed actuators in a robotic arm inspired by the human musculoskeletal system are presented.Experiments demonstrate satisfactory power in tasks like lifting dumbbells(peak power:36 W),playing table tennis(end-effector speed:3.2 m/s),and door opening,without compromising biomimetic aesthetics.Compared to other linear stiffness serial elastic actuators(SEAs),ECA and ICA exhibit high power-to-volume(361×10^(3)W/m^(3))and power-to-mass(111.6 W/kg)ratios respectively,endorsing the biomimetic design’s promise in robotic development.
基金supported by the National Natural Science Foundation of China(Nos.52175277,51905431).
文摘Flying insects are capable of flapping their wings to provide the required power and control forces for flight.A coordinated organizational system including muscles,wings,and control architecture plays a significant role,which provides the sources of inspiration for designing flapping-wing vehicles.In recent years,due to the development of micro-and meso-scale manufacturing technologies,advances in components technologies have directly led to a progress of smaller Flapping-Wing Nano Air Vehicles(FWNAVs)around gram and sub-gram scales,and these air vehicles have gradually acquired insect-like locomotive strategies and capabilities.This paper will present a selective review of components technologies for ultra-lightweight flapping-wing nano air vehicles under 3 g,which covers the novel propulsion methods such as artificial muscles,flight control mechanisms,and the design paradigms of the insect-inspired wings,with a special focus on the development of the driving technologies based on artificial muscles and the progress of the biomimetic wings.The challenges involved in constructing such small flapping-wing air vehicles and recommendations for several possible future directions in terms of component technology enhancements and overall vehicle performance are also discussed in this paper.This review will provide the essential guidelines and the insights for designing a flapping-wing nano air vehicle with higher performance.
基金supported by the National Natural Science Foundation of China(51873223 and 22075154)the Natural Science Foundation of Zhejiang Province(LY19B040001)。
文摘Thermo-responsive shape memory hydrogels generally achieve shape fixation at low temperatures,and shape recovery at high temperatures.However,these hydrogels usually suffer from poor mechanical properties.Herein,we present a unique poly(acrylic acid)/calcium acetate shape memory hydrogel with cold-induced shape recovery performances as ultrastrong artificial muscles.Since the acetate groups could form aggregate at high temperatures and thus induce the association of the hydrogel network,the hydrogel can be fixed into a temporary shape upon heating and recover to its original shape in a cold environment.Moreover,a programmable shape recovery process is realized by adjusting the shape fixing time.In addition,the unique shape memory process enables the application demonstration as bio-inspired artificial muscles with an ultrahigh work density of45.2 kJ m^(-3),higher than that of biological muscles(~8 kJ m^(-3)).
基金National Natural Science Foundation of China(NSFC,Grant No.12272149,11802104)partly supported by the National Key Research and Development Program(Grant No.2017YFB0309200).
文摘High-performance yarn artificial muscles are highly desirable as miniature actuators,sensors,energy harvesters,and soft robotics.However,achieving a yarn artificial muscle that covers all the properties of excellent actuation performance,mechanical robustness,structural stability,and high scalability by a low-cost strategy is still a great challenge.Herein,a bio-inspired fasciated yarn structure is first reported for creating robust high-performance yarn artificial muscles.Unlike conventional strategies that leverage costly materials or complex processing,the developed yarn artificial muscles are constructed by hierarchically helical and sheath-core assembly design of cost-effective common fibers,such as viscose and polyester.The hierarchically helical sheath structure pushes the theoretical limit of the inserted twist in yarns and endows the yarn muscles with large stroke(5815°cm^(-1))and high work capacity(23.5 J kg^(-1)).Due to the rapid water transfer and efficient energy conversion of inter-sheath-core coupling,the as-prepared yarn muscles possess fast response,high rotation accelerated speed,and low recovery hysteresis.Moreover,the inactive core yarn serves as support for internal tethering and load-bearing,enabling these yarn muscles to maintain a self-stable structure,robust life cycle and mechanics.We show that the yarn muscle fabricated in this method is readily available and highly scalable for achieving high-dimensional actuation deformations,which considerably broadens the application scenarios of artificial muscles.
基金supported by the National Key Technologies Research&Development Program of China(Grant No.2018YFB2101000)the National Natural Science Foundation of China(Grant No.51622508).
文摘This paper presents a method for the length-pressure hysteresis modeling of pneumatic artificial muscles(PAMs)by using a modified generalized Prandtl-Ishlinskii(GPI)model.Different from the approaches for establishing the GPI models by replacing the linear envelope functions of operators with hyperbolic tangent and exponential envelop functions,the proposed model is derived by modifying the envelope functions of operators into arc tangent functions,which shows an improvement in the modeling accuracy.The effectiveness of the proposed model is verified by the experimental data of a PAM.Furthermore,its capacity in capturing the hysteresis relationship between length and pressure is testified by giving different input pressure signals.With regard to the computational efficiency,the influence of the number of operators on the modeling accuracy is discussed.Furthermore,the inversion of the GPI model is derived.Its capability of compensating the hysteresis nonlinearities is confirmed via the simulation and experimental study.
基金We gratefully acknowledge the financial support by the Manned Spaceflight Advanced Research Funds(17620504)the Fundamental Research Funds for the Central Universities(16D310606,17D310606,106-06-0019058).
文摘Recently,researches on artificial muscles for imitating the functions of the natural muscles has attracted wide attention.The fiber-shape actuators,shape-memory materials or deforming devices,which are similar to human muscle fiber bundles,have extensively studied and provided more possibilities for artificial muscles.Herein,we develop a thermal responsible fiber-shaped actuator based on the low-cost hollow polyethylene fiber.The sheath-core structured fibrous actuators and the stainless-steel conductive yarn winded pre-stretched polyethylene actuators are fabricated with the heating assisted pre-stretching procedure.The actuation mechanism of the thermal-responsive orientation change of molecular chains driving the actuation is discussed and demonstrated by 2D XRD patterns.These polyethylene-based fibrous actuators displayed three significant advantages including(i)color-turning and shape-changing bifunctional response,(ii)direct joule heating actuation and(iii)effective contraction(18%shrinkage of the pristine length)and lifting ability(the ratio of lifting weight to self-weight is up to 50).
基金This work was supported by National Key R&D Program of China(2018YFB2000903)NationalNatural Science Foundation of China under Grant Numbers 51875507 and 51890885,Open Fund of Key Laboratory of Electronic Equipment Structure Design in Xidian University(EESD1905)applied by Author Yangqiao Lin,which support the research,the Fundamental Research Funds for the Central Universities,and Director’s Fund of State Key Laboratory of Fluid Power and Mechatronic Systems.
文摘Developing artificial muscles that can replace biological muscles to accomplish various tasks iswhat we have long been aiming for.Recent advances in flexible materials and 3D printing technology greatly promote the development of artificial muscle technology.A variety of flexible material-based artificial muscles that are driven by different external stimuli,including pressure,voltage,light,magnetism,temperature,etc.,have been developed.Among these,fluid-driven artificial muscles(FAMs),which can convert the power of fluid(gas or liquid)into the force output and displacement of flexible materials,are the most widely used actuation methods for industrial robots,medical instruments,and human-assisted devices due to their simplicity,excellent safety,large actuation force,high energy efficiency,and low cost.Herein,the bio-design,manufacturing,sensing,control,and applications of FAMs are introduced,including conventional pneumatic/hydraulic artificial muscles and several innovative artificial muscles driven by functional fluids.What’s more,the challenges and future directions of FAMs are discussed.
基金financial supportfrom the National Natural Science Foundation of China(Grant Nos.51605220,U1637101)the Jiangsu Province NaturalScience Foundation(GrantNo.BK20160793)。
文摘Recently,researchers have concentrated on studying ionic polymer metal composite(IPMC)artificial muscle,which has numerous advantages including a relatively large strain under low input voltage,flexibility,high response,low noise,light weight,and high driving energy density.This paper reports recent developments in IPMC artificial muscle,including improvement methods,modeling,and applications.Different types of IPMCs are described,along with various methods for overcoming some shortcomings,including improvement of Nafion matrix membranes,surface preparation of Nafion membranes,the choice of high-performing electrodes,and new electro-active polymers for enhancing the properties of IPMCs.IPMC models are also reviewed,providing theoretical guidance for studying the performance and applications of IPMCs.Successful applications such as bio-inspired robots,opto-mechatronic systems,and medical engineering are discussed.
基金The authors acknowledge the financial support obtained from the National Key Research and Development Program of China(2020YFB1312902)the National Natural Science Foundation of China(21975281)The authors are also grateful for the technical support for Nano-X from Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(SINANO).
文摘Today the developed yarn muscles or actuators still cannot satisfy the requirements of working in high-temperature environ-ments.Thermal resistivity is highly needed in aerospace and industrial protection applications.Herein,an artificial muscle with high-temperature tolerance is prepared using carbon nanotube(CNT)wrapped poly(p-phenylene benzobisoxazole)(PBO)composite yarns.A thermal twisting method was utilized to reorientate the stiff PBO molecular chains into a uniform and twist-stable coiled structure.The CNT/PBO composite yarn muscle generates reversible contractile strokes up to 18.9%under 5.4 MPa tension and outputs 1.3 kJ kg^(-1) energy density.In contrast to previous actuators,which are normally oper-ated at room temperatures,the CNT/PBO composite yarn muscles can work at ambient temperatures up to 300℃ with high contractile stroke and long-term stability.A bionic inchworm robot,a deployable structure,and smart textiles driven by the high-temperature-tolerant yarn muscles were demonstrated,showing the promise as a soft actuator towards high-temperature environment applications.
