Active disturbance-rejection methods are effective in estimating and rejecting disturbances in both transient and steady-state responses.This paper presents a deep observation on and a comparison between two of those ...Active disturbance-rejection methods are effective in estimating and rejecting disturbances in both transient and steady-state responses.This paper presents a deep observation on and a comparison between two of those methods:the generalized extended-state observer(GESO)and the equivalent input disturbance(EID)from assumptions,system configurations,stability conditions,system design,disturbance-rejection performance,and extensibility.A time-domain index is introduced to assess the disturbance-rejection performance.A detailed observation of disturbance-suppression mechanisms reveals the superiority of the EID approach over the GESO method.A comparison between these two methods shows that assumptions on disturbances are more practical and the adjustment of disturbance-rejection performance is easier for the EID approach than for the GESO method.展开更多
In this paper,a new distributed consensus tracking protocol incorporating local disturbance rejection is devised for a multi-agent system with heterogeneous dynamic uncertainties and disturbances over a directed graph...In this paper,a new distributed consensus tracking protocol incorporating local disturbance rejection is devised for a multi-agent system with heterogeneous dynamic uncertainties and disturbances over a directed graph.It is of two-degree-of-freedom nature.Specifically,a robust distributed controller is designed for consensus tracking,while a local disturbance estimator is designed for each agent without requiring the input channel information of disturbances.The condition for asymptotic disturbance rejection is derived.Moreover,even when the disturbance model is not exactly known,the developed method also provides good disturbance-rejection performance.Then,a robust stabilization condition with less conservativeness is derived for the whole multi-agent system.Further,a design algorithm is given.Finally,comparisons with the conventional one-degree-of-freedombased distributed disturbance-rejection method for mismatched disturbances and the distributed extended-state observer for matched disturbances validate the developed method.展开更多
This paper addresses the problems of the robust stability and robust stabilization of a discrete-time system with polytopic uncertainties.A new and simple method is presented to directly decouple the Lyapunov matrix a...This paper addresses the problems of the robust stability and robust stabilization of a discrete-time system with polytopic uncertainties.A new and simple method is presented to directly decouple the Lyapunov matrix and the system dynamic matrix.Combining this method with the parameter-dependent Lyapunov function approach yields new criteria that include some existing ones as special cases.A numerical example illustrates the improvement over the existing ones.展开更多
This paper discusses H-infin it y state feedback control for a networked control system with time-varying delays.Based on the free-weighing matri x method,a delay-dependent stability criterion satisfying a prescribed ...This paper discusses H-infin it y state feedback control for a networked control system with time-varying delays.Based on the free-weighing matri x method,a delay-dependent stability criterion satisfying a prescribed H-infini ty norm bound is presented for an NCS with unknown,time-varying and bounded del ays.And then,the criterion is transformed into suffici ent conditions based on linear matrix inequalities f or H-infinity control.The conditions thus obtained a re also used to design an H-infinity state feed back controller.This design method is further extend ed to solve the design problem of robust H-infin ity state feedback control.A numerical example demo nstrates the validity of the method.展开更多
This paper examines the delay-dependent H-infinity control problem for discrete-time linear systems with time-varying state delays and norm-bounded uncertainties. A new inequality for the finite sum of quadratic terms...This paper examines the delay-dependent H-infinity control problem for discrete-time linear systems with time-varying state delays and norm-bounded uncertainties. A new inequality for the finite sum of quadratic terms is first established. Then, some new delay-dependent criteria are derived by employing the new inequality to guarantee the robust stability of a closed-loop system with a prescribed H-infinity norm bound for all admissible uncertainties and bounded time-vary delays. A numerical example demonstrates that the proposed method is an improvement over existing ones.展开更多
This paper proposes a novel standing assistance robot,which realizes voluntary movements of the patient within a safety motion range.In the previous studies,conventional assistive robots did not require patients to us...This paper proposes a novel standing assistance robot,which realizes voluntary movements of the patient within a safety motion range.In the previous studies,conventional assistive robots did not require patients to use their own physical strength to stand,which led to decreased strength in the elderly.Such general assistive robots helped patients by using a fixed motion reference pathway in spite of their original intention,and as a result,these robots failed to use the physical strength of the patients.Therefore,this study proposes a novel method for assisting the patient to stand up safely while using their physical abilities,by determining the range of movements that can be safely performed from the patient’s physical condition and allowing the patient to move freely within this range.The standing motion is a set of different movements:inclining the trunk forward,lifting the trunk,and extending the trunk.In this study,the range of movements in which the patient can safely stand in each movement is determined in terms of body stability and the muscle output that the patient can generate.Furthermore,this study proposes a robot control method that allows movements based on the patient’s free will if the patient’s posture is within the safety tolerance,and it corrects the movements when the patient’s posture is estimated to fall outside of it.The proposed idea is implemented in our new prototype,and its effectiveness is verified by experimental results with elderly subjects who live in the nursing care house.展开更多
In this paper, we present a design method based on the concept of equivalent input disturbance (EID) to reject disturbances for a linear time-invariant system. A generalized state observer (GSO) is used to estimate an...In this paper, we present a design method based on the concept of equivalent input disturbance (EID) to reject disturbances for a linear time-invariant system. A generalized state observer (GSO) is used to estimate an EID of the external disturbances, and the pole-assignment algorithm is employed to select the matrices of the GSO. Simulation and experimental results of a rotational speed control system demonstrate the validity of our method.展开更多
The Karvonen formula, which is widely used to estimate exercise intensity, contains maximum heart rate, H Rmax, as a variable. This study employed pedaling experiments to assess which of the proposed formulas for calc...The Karvonen formula, which is widely used to estimate exercise intensity, contains maximum heart rate, H Rmax, as a variable. This study employed pedaling experiments to assess which of the proposed formulas for calculating H Rmaxwas the most suitable for use with the Karvonen formula. First, two kinds of experiments involving an ergometer were performed: an all-in-one-day experiment that tested eight pedaling loads in one day, and a one-load-per-day experiment that tested one load per day for eight days.A comparison of the data on 7 subjects showed that the all-in-one-day type of experiment was better for assessing H Rmaxformulas,at least for the load levels tested in our experiments. A statistical analysis of the experimental data on 47 subjects showed two of the H Rmaxformulas to be suitable for use in the Karvonen formula to estimate exercise intensity for males in their 20 s. In addition, the physical characteristics of a person having the greatest impact on exercise intensity were determined.展开更多
Brain hypothermia treatment(BHT) is an active therapy for severe brain injury. It makes the temperature of the brain track a given temperature input curve so as to reduce the risk of tissue damage. BHT requires a brai...Brain hypothermia treatment(BHT) is an active therapy for severe brain injury. It makes the temperature of the brain track a given temperature input curve so as to reduce the risk of tissue damage. BHT requires a brain-temperature control system because of environmental disturbances and changes in the human body. The thermal models of the human body devised so far are usually of a very high order and are not suitable for controlling brain temperature. This paper presents a method of finding a reducedorder thermal model of the human body for use in BHT. It combines minimal realization and balanced realization. Unlike other methods,this method yields a reduced-order model that is based on system theory and that takes the frequency characteristics of human thermal sensation into account. It features high precision in the frequency band for BHT and is suitable for the control of brain temperature.展开更多
基金This work was supported in part by the JSPS(Japan Society for the Promotion of Science)KAKENHI(20H04566,22H03998)the National Natural Science Foundation of China(61873348)+1 种基金the Natural Science Foundation of Hubei Province,China(2020CFA031)Wuhan Applied Foundational Frontier Project(2020010601012175).
文摘Active disturbance-rejection methods are effective in estimating and rejecting disturbances in both transient and steady-state responses.This paper presents a deep observation on and a comparison between two of those methods:the generalized extended-state observer(GESO)and the equivalent input disturbance(EID)from assumptions,system configurations,stability conditions,system design,disturbance-rejection performance,and extensibility.A time-domain index is introduced to assess the disturbance-rejection performance.A detailed observation of disturbance-suppression mechanisms reveals the superiority of the EID approach over the GESO method.A comparison between these two methods shows that assumptions on disturbances are more practical and the adjustment of disturbance-rejection performance is easier for the EID approach than for the GESO method.
基金supported by the National Natural Science Foundation of China(62003010,61873006,61673053)the Beijing Postdoctoral Research Foundation(Q6041001202001)+1 种基金the Postdoctoral Research Foundation of Chaoyang District(Q1041001202101)the National Key Research and Development Project(2018YFC1602704,2018YFB1702704)。
文摘In this paper,a new distributed consensus tracking protocol incorporating local disturbance rejection is devised for a multi-agent system with heterogeneous dynamic uncertainties and disturbances over a directed graph.It is of two-degree-of-freedom nature.Specifically,a robust distributed controller is designed for consensus tracking,while a local disturbance estimator is designed for each agent without requiring the input channel information of disturbances.The condition for asymptotic disturbance rejection is derived.Moreover,even when the disturbance model is not exactly known,the developed method also provides good disturbance-rejection performance.Then,a robust stabilization condition with less conservativeness is derived for the whole multi-agent system.Further,a design algorithm is given.Finally,comparisons with the conventional one-degree-of-freedombased distributed disturbance-rejection method for mismatched disturbances and the distributed extended-state observer for matched disturbances validate the developed method.
基金This work was supported in part by the Doctor Subject Foundation of China (No. 20050533015)the National Science Foundation of China(No. 60425310,60574014).
文摘This paper addresses the problems of the robust stability and robust stabilization of a discrete-time system with polytopic uncertainties.A new and simple method is presented to directly decouple the Lyapunov matrix and the system dynamic matrix.Combining this method with the parameter-dependent Lyapunov function approach yields new criteria that include some existing ones as special cases.A numerical example illustrates the improvement over the existing ones.
文摘This paper discusses H-infin it y state feedback control for a networked control system with time-varying delays.Based on the free-weighing matri x method,a delay-dependent stability criterion satisfying a prescribed H-infini ty norm bound is presented for an NCS with unknown,time-varying and bounded del ays.And then,the criterion is transformed into suffici ent conditions based on linear matrix inequalities f or H-infinity control.The conditions thus obtained a re also used to design an H-infinity state feed back controller.This design method is further extend ed to solve the design problem of robust H-infin ity state feedback control.A numerical example demo nstrates the validity of the method.
基金This work was partially supported by the National Science Foundation of China (No. 60425310, 60574014), the Doctor Subject Foundation of China(No. 20050533015) and the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of the Ministryof Education, P. R. China (TRAPOYT).
文摘This paper examines the delay-dependent H-infinity control problem for discrete-time linear systems with time-varying state delays and norm-bounded uncertainties. A new inequality for the finite sum of quadratic terms is first established. Then, some new delay-dependent criteria are derived by employing the new inequality to guarantee the robust stability of a closed-loop system with a prescribed H-infinity norm bound for all admissible uncertainties and bounded time-vary delays. A numerical example demonstrates that the proposed method is an improvement over existing ones.
基金This work is supported in part by a Grant-in-Aid for Scientific Research B(20H04566),B(22H03998)and C(16K01580)the Japan Society for the Promotion of Science,the Matching Planner Program(VP29117940231)Japan Science and Technology Agency,JST,and Individual Special Research Subsidy from Kwansei Gakuin University.
文摘This paper proposes a novel standing assistance robot,which realizes voluntary movements of the patient within a safety motion range.In the previous studies,conventional assistive robots did not require patients to use their own physical strength to stand,which led to decreased strength in the elderly.Such general assistive robots helped patients by using a fixed motion reference pathway in spite of their original intention,and as a result,these robots failed to use the physical strength of the patients.Therefore,this study proposes a novel method for assisting the patient to stand up safely while using their physical abilities,by determining the range of movements that can be safely performed from the patient’s physical condition and allowing the patient to move freely within this range.The standing motion is a set of different movements:inclining the trunk forward,lifting the trunk,and extending the trunk.In this study,the range of movements in which the patient can safely stand in each movement is determined in terms of body stability and the muscle output that the patient can generate.Furthermore,this study proposes a robot control method that allows movements based on the patient’s free will if the patient’s posture is within the safety tolerance,and it corrects the movements when the patient’s posture is estimated to fall outside of it.The proposed idea is implemented in our new prototype,and its effectiveness is verified by experimental results with elderly subjects who live in the nursing care house.
基金supported by the National Natural Science Foundation of China (Nos. 61210011, 60974045, 61125301)
文摘In this paper, we present a design method based on the concept of equivalent input disturbance (EID) to reject disturbances for a linear time-invariant system. A generalized state observer (GSO) is used to estimate an EID of the external disturbances, and the pole-assignment algorithm is employed to select the matrices of the GSO. Simulation and experimental results of a rotational speed control system demonstrate the validity of our method.
基金supported by Health Science Center Foundation,Japan
文摘The Karvonen formula, which is widely used to estimate exercise intensity, contains maximum heart rate, H Rmax, as a variable. This study employed pedaling experiments to assess which of the proposed formulas for calculating H Rmaxwas the most suitable for use with the Karvonen formula. First, two kinds of experiments involving an ergometer were performed: an all-in-one-day experiment that tested eight pedaling loads in one day, and a one-load-per-day experiment that tested one load per day for eight days.A comparison of the data on 7 subjects showed that the all-in-one-day type of experiment was better for assessing H Rmaxformulas,at least for the load levels tested in our experiments. A statistical analysis of the experimental data on 47 subjects showed two of the H Rmaxformulas to be suitable for use in the Karvonen formula to estimate exercise intensity for males in their 20 s. In addition, the physical characteristics of a person having the greatest impact on exercise intensity were determined.
基金supported by the JSPS KAKENHI(No.26350673)National Natural Science Foundation of China(Nos.61473313 and 61210011)Hubei Provincial Natural Science Foundation of China(No.2015CFA010)
文摘Brain hypothermia treatment(BHT) is an active therapy for severe brain injury. It makes the temperature of the brain track a given temperature input curve so as to reduce the risk of tissue damage. BHT requires a brain-temperature control system because of environmental disturbances and changes in the human body. The thermal models of the human body devised so far are usually of a very high order and are not suitable for controlling brain temperature. This paper presents a method of finding a reducedorder thermal model of the human body for use in BHT. It combines minimal realization and balanced realization. Unlike other methods,this method yields a reduced-order model that is based on system theory and that takes the frequency characteristics of human thermal sensation into account. It features high precision in the frequency band for BHT and is suitable for the control of brain temperature.
