The liquid cooling system(LCS)of fuel cells is challenged by significant time delays,model uncertainties,pump and fan coupling,and frequent disturbances,leading to overshoot and control oscillations that degrade tempe...The liquid cooling system(LCS)of fuel cells is challenged by significant time delays,model uncertainties,pump and fan coupling,and frequent disturbances,leading to overshoot and control oscillations that degrade temperature regulation performance.To address these challenges,we propose a composite control scheme combining fuzzy logic and a variable-gain generalized supertwisting algorithm(VG-GSTA).Firstly,a one-dimensional(1D)fuzzy logic controler(FLC)for the pump ensures stable coolant flow,while a two-dimensional(2D)FLC for the fan regulates the stack temperature near the reference value.The VG-GSTA is then introduced to eliminate steady-state errors,offering resistance to disturbances and minimizing control oscillations.The equilibrium optimizer is used to fine-tune VG-GSTA parameters.Co-simulation verifies the effectiveness of our method,demonstrating its advantages in terms of disturbance immunity,overshoot suppression,tracking accuracy and response speed.展开更多
Tethered Space Net Robot(TSNR)is considered to be a promising approach for space debris removal,and accordingly it is also an interesting control problem due to its time-varying disturbances caused by an elastic and f...Tethered Space Net Robot(TSNR)is considered to be a promising approach for space debris removal,and accordingly it is also an interesting control problem due to its time-varying disturbances caused by an elastic and flexible net and a main connected tether.In this situation,the control scheme should be robust enough,low-frequency,and finite-time convergent in presence of external disturbances.In this paper,a robust controller with an advanced adaptive scheme is proposed.To improve robustness,the disturbance is skillfully involved in the adaptive scheme.It is strictly proven that the closed-loop system can converge to the desired trajectory in finite time in both reaching and sliding processes.Based on the theoretical proof,adaptive gains and corresponding dynamic stability characteristics are further discussed.Finally,the efficiency of the proposed control scheme is numerically proven via a TSNR.The proposed control scheme utilizes small and continuous control forces to compensate for the disturbance efficiently and track the desired trajectory quickly.展开更多
In this paper,a robust torque speed estimator(RTSE)for linear parameter changing(LPC)system is proposed and designed for an encoderless five-phase permanent magnet assisted synchronous reluctance motor(5-phase PMa-Syn...In this paper,a robust torque speed estimator(RTSE)for linear parameter changing(LPC)system is proposed and designed for an encoderless five-phase permanent magnet assisted synchronous reluctance motor(5-phase PMa-SynRM).This estimator is utilized for estimating the rotor speed and the load torque as well as can solve the speed sensor fault problem,as the feedback speed information is obtained directly from the virtual sensor.In addition,this technique is able to enhance the 5-phase PMa-SynRM performance by estimating the load torque for the real time compensation.The stability analysis of the proposed estimator is performed via Schur complement along with Lyapunov analysis.Furthermore,for improving the 5-phase PMa-SynRM performance,five super-twisting sliding mode controllers(ST-SMCs)are employed with providing a robust response without the impacts of high chattering problem.A super-twisting sliding mode speed controller(ST-SMSC)is employed for controlling the PMa-SynRM rotor speed,and four super-twisting sliding mode current controllers(ST-SMCCs)are employed for controlling the 5-phase PMa-SynRM currents.The stability analysis and the experimental results indicate the effectiveness along with feasibility of the proposed RTSE and the ST-SMSC with ST-SMCCs approach for a 750-W 5-phase PMa-SynRM under load disturbance,parameters variations,single open-phase fault,and adjacent two-phase open circuit fault conditions.展开更多
Twisted two-dimensional(2D)layered materials have attracted significant attention due to their twist angle-related superconductivity and moiréexciton phenomena.In twisted layered materials,supertwisted spirals ex...Twisted two-dimensional(2D)layered materials have attracted significant attention due to their twist angle-related superconductivity and moiréexciton phenomena.In twisted layered materials,supertwisted spirals exhibit multiple layers of continuous twisted structures,which give rise to their unique optoelectronic properties.Previous studies have primarily focused on the influence of conical non-Euclidean surfaces on the growth of twisted spirals,revealing their dominant role in determining the twist angle.However,few studies have systematically analyzed the additional factors influencing the variation of twist angles during the growth of such structures.In this work,we demonstrated the synthesis of supertwisted WS_(2) spirals on the edges of WS_(2) nanoribbons with nanoparticles,where the twist angle deviates from the theoretical value due to the additional influence of the nanoribbons during growth.Beyond the dominant role of nanoparticles in determining the twist angle of the spirals,we found that larger step heights or contact areas of the nanoribbons lead to larger twist angles.Furthermore,photoluminescence(PL)and Raman spectroscopy revealed the unique optical properties of the twisted spirals.PL spectra exhibited thickness-dependent abnormal variation in luminescence intensity,attributed to the decoupling and recoupling of interlayer interactions,while Raman spectra demonstrated the thickness-dependent and twist angle-dependent variations in the dominant atomic vibrations of interlayer van der Waals(vdW)interactions.These findings not only provide new insights into the regulation of twist angles in twisted spiral structures,but also contribute to a deeper understanding of the optical characteristics of twisted 2D layered materials,paving the way for their potential applications in various fields.展开更多
基金Supported by the Major Science and Technology Project of Jilin Province(20220301010GX)the International Scientific and Technological Cooperation(20240402071GH).
文摘The liquid cooling system(LCS)of fuel cells is challenged by significant time delays,model uncertainties,pump and fan coupling,and frequent disturbances,leading to overshoot and control oscillations that degrade temperature regulation performance.To address these challenges,we propose a composite control scheme combining fuzzy logic and a variable-gain generalized supertwisting algorithm(VG-GSTA).Firstly,a one-dimensional(1D)fuzzy logic controler(FLC)for the pump ensures stable coolant flow,while a two-dimensional(2D)FLC for the fan regulates the stack temperature near the reference value.The VG-GSTA is then introduced to eliminate steady-state errors,offering resistance to disturbances and minimizing control oscillations.The equilibrium optimizer is used to fine-tune VG-GSTA parameters.Co-simulation verifies the effectiveness of our method,demonstrating its advantages in terms of disturbance immunity,overshoot suppression,tracking accuracy and response speed.
基金supported by the National Natural Science Foundation of China(Nos.62222313 and 62173275)。
文摘Tethered Space Net Robot(TSNR)is considered to be a promising approach for space debris removal,and accordingly it is also an interesting control problem due to its time-varying disturbances caused by an elastic and flexible net and a main connected tether.In this situation,the control scheme should be robust enough,low-frequency,and finite-time convergent in presence of external disturbances.In this paper,a robust controller with an advanced adaptive scheme is proposed.To improve robustness,the disturbance is skillfully involved in the adaptive scheme.It is strictly proven that the closed-loop system can converge to the desired trajectory in finite time in both reaching and sliding processes.Based on the theoretical proof,adaptive gains and corresponding dynamic stability characteristics are further discussed.Finally,the efficiency of the proposed control scheme is numerically proven via a TSNR.The proposed control scheme utilizes small and continuous control forces to compensate for the disturbance efficiently and track the desired trajectory quickly.
文摘In this paper,a robust torque speed estimator(RTSE)for linear parameter changing(LPC)system is proposed and designed for an encoderless five-phase permanent magnet assisted synchronous reluctance motor(5-phase PMa-SynRM).This estimator is utilized for estimating the rotor speed and the load torque as well as can solve the speed sensor fault problem,as the feedback speed information is obtained directly from the virtual sensor.In addition,this technique is able to enhance the 5-phase PMa-SynRM performance by estimating the load torque for the real time compensation.The stability analysis of the proposed estimator is performed via Schur complement along with Lyapunov analysis.Furthermore,for improving the 5-phase PMa-SynRM performance,five super-twisting sliding mode controllers(ST-SMCs)are employed with providing a robust response without the impacts of high chattering problem.A super-twisting sliding mode speed controller(ST-SMSC)is employed for controlling the PMa-SynRM rotor speed,and four super-twisting sliding mode current controllers(ST-SMCCs)are employed for controlling the 5-phase PMa-SynRM currents.The stability analysis and the experimental results indicate the effectiveness along with feasibility of the proposed RTSE and the ST-SMSC with ST-SMCCs approach for a 750-W 5-phase PMa-SynRM under load disturbance,parameters variations,single open-phase fault,and adjacent two-phase open circuit fault conditions.
基金the National Natural Science Foundation of China(No.52273252).
文摘Twisted two-dimensional(2D)layered materials have attracted significant attention due to their twist angle-related superconductivity and moiréexciton phenomena.In twisted layered materials,supertwisted spirals exhibit multiple layers of continuous twisted structures,which give rise to their unique optoelectronic properties.Previous studies have primarily focused on the influence of conical non-Euclidean surfaces on the growth of twisted spirals,revealing their dominant role in determining the twist angle.However,few studies have systematically analyzed the additional factors influencing the variation of twist angles during the growth of such structures.In this work,we demonstrated the synthesis of supertwisted WS_(2) spirals on the edges of WS_(2) nanoribbons with nanoparticles,where the twist angle deviates from the theoretical value due to the additional influence of the nanoribbons during growth.Beyond the dominant role of nanoparticles in determining the twist angle of the spirals,we found that larger step heights or contact areas of the nanoribbons lead to larger twist angles.Furthermore,photoluminescence(PL)and Raman spectroscopy revealed the unique optical properties of the twisted spirals.PL spectra exhibited thickness-dependent abnormal variation in luminescence intensity,attributed to the decoupling and recoupling of interlayer interactions,while Raman spectra demonstrated the thickness-dependent and twist angle-dependent variations in the dominant atomic vibrations of interlayer van der Waals(vdW)interactions.These findings not only provide new insights into the regulation of twist angles in twisted spiral structures,but also contribute to a deeper understanding of the optical characteristics of twisted 2D layered materials,paving the way for their potential applications in various fields.
