A new method was put forward to optimize the position of actuator/sensor of multi-body system with quick startup and brake. Dynamical equation was established for the system with intelligent structure of piezoelectric...A new method was put forward to optimize the position of actuator/sensor of multi-body system with quick startup and brake. Dynamical equation was established for the system with intelligent structure of piezoelectric actuators. According to the property of the modes varying with time, the performance index function was developed based on the optimal configuration principle of energy maximal dissipation, and the relevant optimal model was obtained. According to its characteristic, a float-encoding genetic algorithm, which is efficient, simple and excellent for solving the global-optimal solution of this problem, was adopted. Taking the plane manipulator as an example, the result of numerical calculation shows that, after the actuator/sensor position being optimized, the vibration amplitude of the multi-body system is reduced by 35% compared with that without optimization.展开更多
In order to monitor the basic mechanical properties and interior damage of concrete structures,the piezoelectric actuator/sensor based wave propagation method was investigated experimentally in the laboratory using a ...In order to monitor the basic mechanical properties and interior damage of concrete structures,the piezoelectric actuator/sensor based wave propagation method was investigated experimentally in the laboratory using a specifically designed test setup.The energy attenuation of stress waves was measured by the relative index between the output voltage of sensors and the excitation voltage at the actuator.Based on the experimental results of concrete cube and cylinder specimens,the effect of excitation frequencies,excitation amplitude,wave propagation paths and the curing age on the output signals of sensors are evaluated.The results show that the relative voltage attenuation coefficient RVAC is an effective indicator for measuring the attenuation of stress waves through the interior of concrete.展开更多
The piezothermoelectric actuator/sensor collocation for advanced intelligent structure is studied. The quasi-static equations of piezothermoelasticity are used to analyze the coupling effects between the displaceme...The piezothermoelectric actuator/sensor collocation for advanced intelligent structure is studied. The quasi-static equations of piezothermoelasticity are used to analyze the coupling effects between the displacement, temperature and electric fields of piezothermoelasticity continua and the governing equations for piezothermoelasticity continua are derived to discuss the effects of coupling factors on the control/sensing performance in intelligent structure. Based on those analyses, a finite element analysis model of distributed piezothertnoelectric continua is developed later. The thermal stress and deformation of a beam are calculated by FEA method so as to determine the optimal actuator/sensor placement. Based on the results of the optimal analysis procedure of actuator/sensor placement, some conclusions of actuator/sensor placement are obtained. Thus, the optimal actuator/sensor placement for piezothermoelectric intelligent structure can be found from the actuator/sensor placements available so that intelligent system will have the best controllability and observability.展开更多
In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and l...In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and lower constraints and the sensor in the feedback loop is subjected to network-induced unknown time-varying delay and noise.With this nonlinear control method,we first employ right coprime factorization based on isomorphism and operator theory to factorize the plant,so that bounded input bounded output(BIBO)stability can be guaranteed.Next,continuous-time generalized predictive control(CGPC)is utilized for the unstable operator of the right coprime factorized plant to guarantee inner stability and enables the closed-loop dynamics of the system with predictive characteristics.Meanwhile,a second-Do F(degrees of freedom)switched controller that satisfies a perturbed Bezout identity and a robustness condition is designed.By using the CGPC controller that possesses predictive behavior and the second-Do F switched stabilizer,the overall stability of the plant subjected to actuator limitations is guaranteed.To address sensor limitations that exist in networked plants in the form of delay and noise which often cause system performance degradation,we implement an identity operator definition in the feedback loop to compensate for these adverse effects.Further,a pre-operator is designed to ensure that the plant output tracks the reference input.Finally,the effectiveness of the proposed design scheme is demonstrated by simulations.展开更多
This research paper tackles the complexities of achieving global fuzzy consensus in leader-follower systems in robotic systems,focusing on robust control systems against an advanced signal attack that integrates senso...This research paper tackles the complexities of achieving global fuzzy consensus in leader-follower systems in robotic systems,focusing on robust control systems against an advanced signal attack that integrates sensor and actuator disturbances within the dynamics of follower robots.Each follower robot has unknown dynamics and control inputs,which expose it to the risks of both sensor and actuator attacks.The leader robot,described by a secondorder,time-varying nonlinear model,transmits its position,velocity,and acceleration information to follower robots through a wireless connection.To handle the complex setup and communication among robots in the network,we design a robust hybrid distributed adaptive control strategy combining the effect of sensor and actuator attack,which ensures asymptotic consensus,extending beyond conventional bounded consensus results.The proposed framework employs fuzzy logic systems(FLSs)as proactive controllers to estimate unknown nonlinear behaviors,while also effectively managing sensor and actuator attacks,ensuring stable consensus among all agents.To counter the impact of the combined signal attack on follower dynamics,a specialized robust control mechanism is designed,sustaining system stability and performance under adversarial conditions.The efficiency of this control strategy is demonstrated through simulations conducted across two different directed communication topologies,underscoring the protocol’s adaptability,resilience,and effectiveness in maintaining global consensus under complex attack scenarios.展开更多
Hydraulic-electric systems are widely utilized in various applications.However,over time,these systems may encounter random faults such as loose cables,ambient environmental noise,or sensor aging,leading to inaccurate...Hydraulic-electric systems are widely utilized in various applications.However,over time,these systems may encounter random faults such as loose cables,ambient environmental noise,or sensor aging,leading to inaccurate sensor readings.These faults may result in system instability or compromise safety.In this paper,we propose a fault compensation control system to mitigate the effects of sensor faults and ensure system safety.Specifically,we utilize the pressure sensor within the system to implement the control process and evaluate performance based on the piston position.First,we develop a mathematical model to identify optimal parameters for the fault estimation model based on the Lyapunov stability principle.Next,we design an unknown input observer that estimates the state vector and detects pressure sensor faults using a linear matrix inequality optimization algorithm.The estimated pressure faults are incorporated into the fault compensation control system to counteract their effects via a fault residual coefficient.The discrepancy between the feedback state and the estimated state determines this coefficient.We assess the piston position’s performance through pressure control to evaluate the proposed model’s effectiveness.Finally,the system simulation results are analyzed to validate the efficiency of the proposed model.When a pressure sensor fault occurs,the proposed approach effectively minimizes position control errors,enhancing overall system stability.When a pressure sensor fault occurs,the proposed model compensates for the fault to mitigate the impact of pressure problem,thereby enhancing the position control quality of the EHA system.The fault compensation method ensures over 90%system performance,with its effectiveness becoming more evident under pressure sensor faults.展开更多
A rectangular finite element for laminated plate with bonded and/or embedded piezoelectric sensors and actuators is developed based on the variational principle and the first order shear deformation theory. The elemen...A rectangular finite element for laminated plate with bonded and/or embedded piezoelectric sensors and actuators is developed based on the variational principle and the first order shear deformation theory. The element has four-node, 20-degrees-of-freedom with one potential degree of freedom for each piezoelectric layer to represent the piezoelectric behavior. The higher order derivation of deflection is obtained by using the normal rotation expressions to take the effects of transverse shear deformation into considerations. The finite element can accurately simulate the deformation of both thin and moderately thick plates. A Fortran program is written and a number of benchmark tests are exercised to verify its effectiveness. Results are compared well with the existing data. The unbalanced composite with piezoelectric layers is then analyzed by using the model. Results show that the changes of the ratio between the thickness of positive angle layers and the negative angle layers have an effect on the deformation of the structure under the same electric loading.展开更多
An intelligent emergency service（ IES） system is designed for indoor environments based on a wireless sensor and actuator network（ WSAN） composed of a gateway, sensor nodes, and a multi-robot system（ MRS）. If th...An intelligent emergency service（ IES） system is designed for indoor environments based on a wireless sensor and actuator network（ WSAN） composed of a gateway, sensor nodes, and a multi-robot system（ MRS）. If the MRS receives accident alarm information, the group of robots will navigate to the accident sites and provide corresponding emergency services.According to the characteristics of the MRS, a distributed consensus formation protocol is designed, which can assure that the multiple robots arrive at the accident site in a specified formation. The prototype emergency service system was designed and implemented, and some relevant simulations and experiments were carried out. The results showthat the MRS can successfully provide emergency lighting and failure node replacement services when accidents happen. The effectiveness of the algorithm and the feasibility of the system are verified.展开更多
With the advance of smart material science,robotics is evolving from rigid robots to soft robots.Compared to rigid robots,soft robots can safely interact with the environment,easily navigate in unstructured fields,and...With the advance of smart material science,robotics is evolving from rigid robots to soft robots.Compared to rigid robots,soft robots can safely interact with the environment,easily navigate in unstructured fields,and be minimized to operate in narrow spaces,owning to the new actuation and sensing technologies developed by the smart materials.In the review,different actuation and sensing technologies based on different smart materials are analyzed and summarized.According to the driving or feedback signals,actuators are categorized into electrically responsive actuators,thermally responsive actuators,magnetically responsive actuators,and photoresponsive actuators;sensors are categorized into resistive sensors,capacitive sensors,magnetic sensors,and optical waveguide sensors.After introducing the principle and several robotic prototypes of some typical materials in each category of the actuators and sensors.The advantages and disadvantages of the actuators and sensors are compared based on the categories,and their potential applications in robotics are also presented.展开更多
In this paper,the control problem of distributed parameter systems is investigated by using wireless sensor and actuator networks with the observer-based method.Firstly,a centralized observer which makes use of the me...In this paper,the control problem of distributed parameter systems is investigated by using wireless sensor and actuator networks with the observer-based method.Firstly,a centralized observer which makes use of the measurement information provided by the fixed sensors is designed to estimate the distributed parameter systems.The mobile agents,each of which is affixed with a controller and an actuator,can provide the observer-based control for the target systems.By using Lyapunov stability arguments,the stability for the estimation error system and distributed parameter control system is proved,meanwhile a guidance scheme for each mobile actuator is provided to improve the control performance.A numerical example is finally used to demonstrate the effectiveness and the advantages of the proposed approaches.展开更多
In this paper, an open-loop PD-type iterative learning control(ILC) scheme is first proposed for two kinds of distributed parameter systems(DPSs) which are described by parabolic partial differential equations using n...In this paper, an open-loop PD-type iterative learning control(ILC) scheme is first proposed for two kinds of distributed parameter systems(DPSs) which are described by parabolic partial differential equations using non-collocated sensors and actuators. Then, a closed-loop PD-type ILC algorithm is extended to a class of distributed parameter systems with a non-collocated single sensor and m actuators when the initial states of the system exist some errors. Under some given assumptions, the convergence conditions of output errors for the systems can be obtained. Finally, one numerical example for a distributed parameter system with a single sensor and two actuators is presented to illustrate the effectiveness of the proposed ILC schemes.展开更多
In vibration active control of composite structures, piezoelectricsensors/actuators are usually bonded to the surface of a host structure. Debonding of piezoelectricsensors/actuators can result in significant changes ...In vibration active control of composite structures, piezoelectricsensors/actuators are usually bonded to the surface of a host structure. Debonding of piezoelectricsensors/actuators can result in significant changes to the static and dynamic response. In thepresent paper, an novel Enhanced Assumed Strain(EAS) piezoelectric solid element formulation isdeveloped for vibration active control of laminated structures bonded with piezoelectric sensors andactuators. Unlike the conventional brick elements, the present formulation is very reliable, moreaccurate, and computationally efficient and can be used to model the response of shell structuresbesides thin plates. Delaminations are modeled by pairs of nodes with the same coordinates butdifferent node numbers, and numerical results demonstrate the performance of the element and theglobal and local effects of debonding sensors/actuators on the dynamics of the adaptive laminates.展开更多
The topic of vibration control with distributed actuators has been the subject of many researches. This paper is concerned with the vibration control of a cantilever beam equipped with piezoelectric ceramics as senso...The topic of vibration control with distributed actuators has been the subject of many researches. This paper is concerned with the vibration control of a cantilever beam equipped with piezoelectric ceramics as sensors and actuators. One piezoelectric ceramic is bonded to the structure and provides control input for the structure, while the other piezoelectric ceramic provides the feedback signal. An approach to identification and control is presented. Observation spillover is eliminated by prefiltering the sensor data. A procedure used to determine actuator and sensor location, is discussed based on the modes to be controlled. Finally, the experimental results are presented to verify the proposed method.展开更多
Component failures can cause multi-agent system(MAS)performance degradation and even disasters,which provokes the demand of the fault diagnosis method.A distributed sliding mode observer-based fault diagnosis method f...Component failures can cause multi-agent system(MAS)performance degradation and even disasters,which provokes the demand of the fault diagnosis method.A distributed sliding mode observer-based fault diagnosis method for MAS is developed in presence of actuator and sensor faults.Firstly,the actuator and sensor faults are extended to the system state,and the system is transformed into a descriptor system form.Then,a sliding mode-based distributed unknown input observer is proposed to estimate the extended state.Furthermore,adaptive laws are introduced to adjust the observer parameters.Finally,the effectiveness of the proposed method is demonstrated with numerical simulations.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
One of the main problems in controlling the shape of active structures （AS） is to determine the actuations that drive the structure from the current state to the target state. Model-based methods such as stochastic ...One of the main problems in controlling the shape of active structures （AS） is to determine the actuations that drive the structure from the current state to the target state. Model-based methods such as stochastic search require a known type of load and relatively long computational time, which limits the practical use of AS in civil engineering. Moreover, additive errors may be produced because of the discrepancy between analytic models and real structures. To overcome these limitations, this paper presents a compound system called WAS, which combines AS with a wireless sensor and actuator network （WSAN）. A bio-inspired control framework imitating the activity of the nervous systems of animals is proposed for WAS. A typical example is tested for verification. In the example, a triangular tensegrity prism that aims to maintain its original height is integrated with a WSAN that consists of a central controller, three actuators, and three sensors. The result demonstrates the feasibility of the proposed concept and control framework in cases of unknown loads that include different types, distributions, magnitudes, and directions. The proposed control framework can also act as a supplementary means to improve the efficiency and accuracy of control frameworks based on a common stochastic search.展开更多
As a kind of ionic artificial muscle material,Ionic Polymer-Metal Composites(IPMCs)have the advantages of a low drive current,light weight,and significant flexibility.IPMCs are widely used in the fields of biomedicine...As a kind of ionic artificial muscle material,Ionic Polymer-Metal Composites(IPMCs)have the advantages of a low drive current,light weight,and significant flexibility.IPMCs are widely used in the fields of biomedicine,soft robots,etc.However,the displacement and blocking force of the traditional sheet-type Nafion-IPMC need to be improved,and it has the limitation of unidirectional actuation.In this paper,a new type of short side chain Aquivion material is used as the polymer in the IPMC.The cylindrical IPMC is prepared by extrusion technology to improve its actuation performance and realize multi-degree-of-freedom motion.In comparison to the traditional Nafion-IPMC,the ion exchange capacity,specific capacitance,and conductivity of Aquivion-IPMC are improved by 28%,27%,and 32%,respectively,and the displacement and blocking force are improved by 57%and 25%,respectively.The cylindrical actuators can be deflected in eight directions.This indicates that Aquivion,as a polymer membrane for IPMC,holds significant application potential.By designing a cylindrical IPMC electrode distribution,the multi-degree-of-freedom deflection of IPMC can be realized.展开更多
The actuator and sensor placement problem for active vibration control of large cable net structures is investigated in this paper.Since the structures exhibit closely spaced modes in the range of low frequencies,the ...The actuator and sensor placement problem for active vibration control of large cable net structures is investigated in this paper.Since the structures exhibit closely spaced modes in the range of low frequencies,the number of modes to be considered is quite large after modal truncation,while only a limited number of actuators and sensors are to be placed.This makes it hard to determine the actuator and sensor locations with the existing placement methods in the literature such as the methods based on the controllability/observability grammian.To deal with this issue,an actuator and sensor placement method based on singular value decompositions(SVD)of the input and output matrices is proposed,which guarantees the modal controllability and observability of the system.The effectiveness of the SVD based method is verified through numerical simulations in which comparisons are conducted between randomly-chosen locations and the optimal ones obtained by a genetic algorithm.展开更多
To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical character...To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical characteristics of the actuator in the presence of various combinations of process parameters,combined with the orthogonal test method of"four factors and three levels".The bending and sensing characteristics of actuators of various sizes are methodically examined using a self-made bending polypyrrole actuator.The functional relationship between the bending displacement and the output voltage signal is established by studying the characteristics of the actuator sensor subjected to various degrees of bending.The experimental results reveal that the bending displacement of the actuator tip almost exhibits a linear variation as a function of length and width.When the voltage reaches 0.8 V,the bending speed of the actuator tends to be stable.Finally,the mechanical properties of the self-assembled polypyrrole actuator are verified by the design and fabrication of the microgripper.展开更多
Wireless sensor and actuator network is the key technology of service robot intelligent space. This paper is concerned with design and implementation of a ZigBee based wireless sensor and actuator network (hereinafter...Wireless sensor and actuator network is the key technology of service robot intelligent space. This paper is concerned with design and implementation of a ZigBee based wireless sensor and actuator network (hereinafter referred to as ZWSAN), which has been applied in our service robot intelligent space successfully. Firstly, a simplified ZigBee stack applied to ZWSAN is proposed and the primitives of the stack are illustrated after a short overview of ZigBee protocols. Then the implementation of hardware module and software stack is introduced in detail as well as several representative devices integrated into ZWSAN, including environmental sensors for environmental perception, home devices controllers for device control, embedded speech recognition module for speech control, IMU module for abnormal behaviors detection and laser robot control for service robot navigation. An application example is described to demonstrate how the devices in ZWSAN to provide service cooperatively. Finally, we conclude this paper and discuss the future directions.展开更多
基金Project(50390063) supported by the National Natural Science Foundation of China
文摘A new method was put forward to optimize the position of actuator/sensor of multi-body system with quick startup and brake. Dynamical equation was established for the system with intelligent structure of piezoelectric actuators. According to the property of the modes varying with time, the performance index function was developed based on the optimal configuration principle of energy maximal dissipation, and the relevant optimal model was obtained. According to its characteristic, a float-encoding genetic algorithm, which is efficient, simple and excellent for solving the global-optimal solution of this problem, was adopted. Taking the plane manipulator as an example, the result of numerical calculation shows that, after the actuator/sensor position being optimized, the vibration amplitude of the multi-body system is reduced by 35% compared with that without optimization.
基金Funded by the National Natural Science Foundation of China (No.50708065)the National High-tech R&D Program(863 Program )(No.2007-AA-11-Z-113)the Key Projects in the Science and Technology Pillar Program of Tianjin(No.11ZCKFSF00300)
文摘In order to monitor the basic mechanical properties and interior damage of concrete structures,the piezoelectric actuator/sensor based wave propagation method was investigated experimentally in the laboratory using a specifically designed test setup.The energy attenuation of stress waves was measured by the relative index between the output voltage of sensors and the excitation voltage at the actuator.Based on the experimental results of concrete cube and cylinder specimens,the effect of excitation frequencies,excitation amplitude,wave propagation paths and the curing age on the output signals of sensors are evaluated.The results show that the relative voltage attenuation coefficient RVAC is an effective indicator for measuring the attenuation of stress waves through the interior of concrete.
基金The project is supported by National Natural Science Foundation of China (59805018)
文摘The piezothermoelectric actuator/sensor collocation for advanced intelligent structure is studied. The quasi-static equations of piezothermoelasticity are used to analyze the coupling effects between the displacement, temperature and electric fields of piezothermoelasticity continua and the governing equations for piezothermoelasticity continua are derived to discuss the effects of coupling factors on the control/sensing performance in intelligent structure. Based on those analyses, a finite element analysis model of distributed piezothertnoelectric continua is developed later. The thermal stress and deformation of a beam are calculated by FEA method so as to determine the optimal actuator/sensor placement. Based on the results of the optimal analysis procedure of actuator/sensor placement, some conclusions of actuator/sensor placement are obtained. Thus, the optimal actuator/sensor placement for piezothermoelectric intelligent structure can be found from the actuator/sensor placements available so that intelligent system will have the best controllability and observability.
文摘In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and lower constraints and the sensor in the feedback loop is subjected to network-induced unknown time-varying delay and noise.With this nonlinear control method,we first employ right coprime factorization based on isomorphism and operator theory to factorize the plant,so that bounded input bounded output(BIBO)stability can be guaranteed.Next,continuous-time generalized predictive control(CGPC)is utilized for the unstable operator of the right coprime factorized plant to guarantee inner stability and enables the closed-loop dynamics of the system with predictive characteristics.Meanwhile,a second-Do F(degrees of freedom)switched controller that satisfies a perturbed Bezout identity and a robustness condition is designed.By using the CGPC controller that possesses predictive behavior and the second-Do F switched stabilizer,the overall stability of the plant subjected to actuator limitations is guaranteed.To address sensor limitations that exist in networked plants in the form of delay and noise which often cause system performance degradation,we implement an identity operator definition in the feedback loop to compensate for these adverse effects.Further,a pre-operator is designed to ensure that the plant output tracks the reference input.Finally,the effectiveness of the proposed design scheme is demonstrated by simulations.
文摘This research paper tackles the complexities of achieving global fuzzy consensus in leader-follower systems in robotic systems,focusing on robust control systems against an advanced signal attack that integrates sensor and actuator disturbances within the dynamics of follower robots.Each follower robot has unknown dynamics and control inputs,which expose it to the risks of both sensor and actuator attacks.The leader robot,described by a secondorder,time-varying nonlinear model,transmits its position,velocity,and acceleration information to follower robots through a wireless connection.To handle the complex setup and communication among robots in the network,we design a robust hybrid distributed adaptive control strategy combining the effect of sensor and actuator attack,which ensures asymptotic consensus,extending beyond conventional bounded consensus results.The proposed framework employs fuzzy logic systems(FLSs)as proactive controllers to estimate unknown nonlinear behaviors,while also effectively managing sensor and actuator attacks,ensuring stable consensus among all agents.To counter the impact of the combined signal attack on follower dynamics,a specialized robust control mechanism is designed,sustaining system stability and performance under adversarial conditions.The efficiency of this control strategy is demonstrated through simulations conducted across two different directed communication topologies,underscoring the protocol’s adaptability,resilience,and effectiveness in maintaining global consensus under complex attack scenarios.
基金supported by Nguyen Tat Thanh University,Ho Chi Minh City,Vietnam,provided with the facilities required to carry out this work.
文摘Hydraulic-electric systems are widely utilized in various applications.However,over time,these systems may encounter random faults such as loose cables,ambient environmental noise,or sensor aging,leading to inaccurate sensor readings.These faults may result in system instability or compromise safety.In this paper,we propose a fault compensation control system to mitigate the effects of sensor faults and ensure system safety.Specifically,we utilize the pressure sensor within the system to implement the control process and evaluate performance based on the piston position.First,we develop a mathematical model to identify optimal parameters for the fault estimation model based on the Lyapunov stability principle.Next,we design an unknown input observer that estimates the state vector and detects pressure sensor faults using a linear matrix inequality optimization algorithm.The estimated pressure faults are incorporated into the fault compensation control system to counteract their effects via a fault residual coefficient.The discrepancy between the feedback state and the estimated state determines this coefficient.We assess the piston position’s performance through pressure control to evaluate the proposed model’s effectiveness.Finally,the system simulation results are analyzed to validate the efficiency of the proposed model.When a pressure sensor fault occurs,the proposed approach effectively minimizes position control errors,enhancing overall system stability.When a pressure sensor fault occurs,the proposed model compensates for the fault to mitigate the impact of pressure problem,thereby enhancing the position control quality of the EHA system.The fault compensation method ensures over 90%system performance,with its effectiveness becoming more evident under pressure sensor faults.
文摘A rectangular finite element for laminated plate with bonded and/or embedded piezoelectric sensors and actuators is developed based on the variational principle and the first order shear deformation theory. The element has four-node, 20-degrees-of-freedom with one potential degree of freedom for each piezoelectric layer to represent the piezoelectric behavior. The higher order derivation of deflection is obtained by using the normal rotation expressions to take the effects of transverse shear deformation into considerations. The finite element can accurately simulate the deformation of both thin and moderately thick plates. A Fortran program is written and a number of benchmark tests are exercised to verify its effectiveness. Results are compared well with the existing data. The unbalanced composite with piezoelectric layers is then analyzed by using the model. Results show that the changes of the ratio between the thickness of positive angle layers and the negative angle layers have an effect on the deformation of the structure under the same electric loading.
基金The National Natural Science Foundation of China(No.61375076)the Research&Innovation Program for Graduate Student in Universities of Jiangsu Province(No.KYLX_0108)+1 种基金the Scientific Research Foundation of Graduate School of Southeast University(No.YBJJ1423)Jiangsu Planned Projects for Postdoctoral Research Funds(No.1302064B)
文摘An intelligent emergency service（ IES） system is designed for indoor environments based on a wireless sensor and actuator network（ WSAN） composed of a gateway, sensor nodes, and a multi-robot system（ MRS）. If the MRS receives accident alarm information, the group of robots will navigate to the accident sites and provide corresponding emergency services.According to the characteristics of the MRS, a distributed consensus formation protocol is designed, which can assure that the multiple robots arrive at the accident site in a specified formation. The prototype emergency service system was designed and implemented, and some relevant simulations and experiments were carried out. The results showthat the MRS can successfully provide emergency lighting and failure node replacement services when accidents happen. The effectiveness of the algorithm and the feasibility of the system are verified.
基金Supported by National Key Research and Development Program of China(Grant No.2019YFB 1309800)National Natural Science Foundation of China(Grant Nos.62173197,91848206)Beijing Science&Technology Project(Grant No.Z191100008019008).
文摘With the advance of smart material science,robotics is evolving from rigid robots to soft robots.Compared to rigid robots,soft robots can safely interact with the environment,easily navigate in unstructured fields,and be minimized to operate in narrow spaces,owning to the new actuation and sensing technologies developed by the smart materials.In the review,different actuation and sensing technologies based on different smart materials are analyzed and summarized.According to the driving or feedback signals,actuators are categorized into electrically responsive actuators,thermally responsive actuators,magnetically responsive actuators,and photoresponsive actuators;sensors are categorized into resistive sensors,capacitive sensors,magnetic sensors,and optical waveguide sensors.After introducing the principle and several robotic prototypes of some typical materials in each category of the actuators and sensors.The advantages and disadvantages of the actuators and sensors are compared based on the categories,and their potential applications in robotics are also presented.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61174021 and 61473136)the 111 Project of China(Grant No.B12018)
文摘In this paper,the control problem of distributed parameter systems is investigated by using wireless sensor and actuator networks with the observer-based method.Firstly,a centralized observer which makes use of the measurement information provided by the fixed sensors is designed to estimate the distributed parameter systems.The mobile agents,each of which is affixed with a controller and an actuator,can provide the observer-based control for the target systems.By using Lyapunov stability arguments,the stability for the estimation error system and distributed parameter control system is proved,meanwhile a guidance scheme for each mobile actuator is provided to improve the control performance.A numerical example is finally used to demonstrate the effectiveness and the advantages of the proposed approaches.
基金supported by National Natural Science Foundation of China(61807016)Postgraduate Research and Practice Innovation Program of Jiangsu Province(KYCX18-1859)。
文摘In this paper, an open-loop PD-type iterative learning control(ILC) scheme is first proposed for two kinds of distributed parameter systems(DPSs) which are described by parabolic partial differential equations using non-collocated sensors and actuators. Then, a closed-loop PD-type ILC algorithm is extended to a class of distributed parameter systems with a non-collocated single sensor and m actuators when the initial states of the system exist some errors. Under some given assumptions, the convergence conditions of output errors for the systems can be obtained. Finally, one numerical example for a distributed parameter system with a single sensor and two actuators is presented to illustrate the effectiveness of the proposed ILC schemes.
文摘In vibration active control of composite structures, piezoelectricsensors/actuators are usually bonded to the surface of a host structure. Debonding of piezoelectricsensors/actuators can result in significant changes to the static and dynamic response. In thepresent paper, an novel Enhanced Assumed Strain(EAS) piezoelectric solid element formulation isdeveloped for vibration active control of laminated structures bonded with piezoelectric sensors andactuators. Unlike the conventional brick elements, the present formulation is very reliable, moreaccurate, and computationally efficient and can be used to model the response of shell structuresbesides thin plates. Delaminations are modeled by pairs of nodes with the same coordinates butdifferent node numbers, and numerical results demonstrate the performance of the element and theglobal and local effects of debonding sensors/actuators on the dynamics of the adaptive laminates.
文摘The topic of vibration control with distributed actuators has been the subject of many researches. This paper is concerned with the vibration control of a cantilever beam equipped with piezoelectric ceramics as sensors and actuators. One piezoelectric ceramic is bonded to the structure and provides control input for the structure, while the other piezoelectric ceramic provides the feedback signal. An approach to identification and control is presented. Observation spillover is eliminated by prefiltering the sensor data. A procedure used to determine actuator and sensor location, is discussed based on the modes to be controlled. Finally, the experimental results are presented to verify the proposed method.
基金supported by the National Natural Science Foundation of China(62020106003,62003162)111 project(B20007)+1 种基金the Natural Science Foundation of Jiangsu Province of China(BK20200416)the China Postdoctoral Science Foundation(2020TQ0151,2020M681590).
文摘Component failures can cause multi-agent system(MAS)performance degradation and even disasters,which provokes the demand of the fault diagnosis method.A distributed sliding mode observer-based fault diagnosis method for MAS is developed in presence of actuator and sensor faults.Firstly,the actuator and sensor faults are extended to the system state,and the system is transformed into a descriptor system form.Then,a sliding mode-based distributed unknown input observer is proposed to estimate the extended state.Furthermore,adaptive laws are introduced to adjust the observer parameters.Finally,the effectiveness of the proposed method is demonstrated with numerical simulations.
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Project supported by the National Key Technology R&D Program of China(No.2012BAJ07B03)the National Natural Science Foundation of China(Nos.51178415 and 51578491)
文摘One of the main problems in controlling the shape of active structures （AS） is to determine the actuations that drive the structure from the current state to the target state. Model-based methods such as stochastic search require a known type of load and relatively long computational time, which limits the practical use of AS in civil engineering. Moreover, additive errors may be produced because of the discrepancy between analytic models and real structures. To overcome these limitations, this paper presents a compound system called WAS, which combines AS with a wireless sensor and actuator network （WSAN）. A bio-inspired control framework imitating the activity of the nervous systems of animals is proposed for WAS. A typical example is tested for verification. In the example, a triangular tensegrity prism that aims to maintain its original height is integrated with a WSAN that consists of a central controller, three actuators, and three sensors. The result demonstrates the feasibility of the proposed concept and control framework in cases of unknown loads that include different types, distributions, magnitudes, and directions. The proposed control framework can also act as a supplementary means to improve the efficiency and accuracy of control frameworks based on a common stochastic search.
基金financial support from the National Natural Science Foundation of China(Grant No.U1637101)The Research Fund of State Key Laboratory of Mechanics and Control for Aerospace Structures(1005-ZAG23011).
文摘As a kind of ionic artificial muscle material,Ionic Polymer-Metal Composites(IPMCs)have the advantages of a low drive current,light weight,and significant flexibility.IPMCs are widely used in the fields of biomedicine,soft robots,etc.However,the displacement and blocking force of the traditional sheet-type Nafion-IPMC need to be improved,and it has the limitation of unidirectional actuation.In this paper,a new type of short side chain Aquivion material is used as the polymer in the IPMC.The cylindrical IPMC is prepared by extrusion technology to improve its actuation performance and realize multi-degree-of-freedom motion.In comparison to the traditional Nafion-IPMC,the ion exchange capacity,specific capacitance,and conductivity of Aquivion-IPMC are improved by 28%,27%,and 32%,respectively,and the displacement and blocking force are improved by 57%and 25%,respectively.The cylindrical actuators can be deflected in eight directions.This indicates that Aquivion,as a polymer membrane for IPMC,holds significant application potential.By designing a cylindrical IPMC electrode distribution,the multi-degree-of-freedom deflection of IPMC can be realized.
基金National Natural Science Foundation of China(11290153)。
文摘The actuator and sensor placement problem for active vibration control of large cable net structures is investigated in this paper.Since the structures exhibit closely spaced modes in the range of low frequencies,the number of modes to be considered is quite large after modal truncation,while only a limited number of actuators and sensors are to be placed.This makes it hard to determine the actuator and sensor locations with the existing placement methods in the literature such as the methods based on the controllability/observability grammian.To deal with this issue,an actuator and sensor placement method based on singular value decompositions(SVD)of the input and output matrices is proposed,which guarantees the modal controllability and observability of the system.The effectiveness of the SVD based method is verified through numerical simulations in which comparisons are conducted between randomly-chosen locations and the optimal ones obtained by a genetic algorithm.
基金Funded by the National Natural Science Foundation of Hunan Province,Chinal(No.2021JJ60012)。
文摘To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical characteristics of the actuator in the presence of various combinations of process parameters,combined with the orthogonal test method of"four factors and three levels".The bending and sensing characteristics of actuators of various sizes are methodically examined using a self-made bending polypyrrole actuator.The functional relationship between the bending displacement and the output voltage signal is established by studying the characteristics of the actuator sensor subjected to various degrees of bending.The experimental results reveal that the bending displacement of the actuator tip almost exhibits a linear variation as a function of length and width.When the voltage reaches 0.8 V,the bending speed of the actuator tends to be stable.Finally,the mechanical properties of the self-assembled polypyrrole actuator are verified by the design and fabrication of the microgripper.
文摘Wireless sensor and actuator network is the key technology of service robot intelligent space. This paper is concerned with design and implementation of a ZigBee based wireless sensor and actuator network (hereinafter referred to as ZWSAN), which has been applied in our service robot intelligent space successfully. Firstly, a simplified ZigBee stack applied to ZWSAN is proposed and the primitives of the stack are illustrated after a short overview of ZigBee protocols. Then the implementation of hardware module and software stack is introduced in detail as well as several representative devices integrated into ZWSAN, including environmental sensors for environmental perception, home devices controllers for device control, embedded speech recognition module for speech control, IMU module for abnormal behaviors detection and laser robot control for service robot navigation. An application example is described to demonstrate how the devices in ZWSAN to provide service cooperatively. Finally, we conclude this paper and discuss the future directions.
