Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among th...Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among the input axes,and coupled linear and angular motions of the end effector.This paper presents an inverse hysteresis-coupling hybrid model to account for such hysteresis and couplings.First,a specially designed kinematic chain is adopted to transfer the pose of the end effector into the linear motions at three prismatic joints.Second,an inverse hysteresis-coupling hybrid model is developed to linearize and decouple the system via a multilayer feedforward neural network.A fractional-order PID controller is also integrated to improve the motion accuracy of the overall system.Experimental results demonstrate that the proposed method can accurately control the motion of the end effector with improved accuracy and robustness.展开更多
Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper ...Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper proposes a phase-split power decoupling unbalanced compensation strategy based load balancing strategy for 3P4L based M-LVDC.Firstly,the topology and operation principle of the 3P4L-based M-LVDC system is introduced,and quasi-proportional resonant(QPR)based phase-split power current control for the 3P4L converter is proposed.Secondly,a load-balancing control strategy considering unbalanced compensation for 3P4L-based MLVDC is presented,in which the control diagrams for each 3P4L-based converter are detailed.The core idea of the proposed strategy is to comprehensively consider the imbalance compensation and load rate balancing between the two areas to calculate the split-phase power and current reference values of each 3P4L converter and achieve the static error-free tracking of the reference values through the QPR current inner-loop control.These reference values are then tracked with zero steady-state error using QPR current inner-loop control.Finally,the effectiveness of the proposed control strategy is verified through a 3P4L M-LVDC case study conducted on the PSCAD/EMTDC software.Theresults indicate that the proposed method not only can reduce the three-phase imbalance degrees from>20% to<0.5%,but also achieve excellent balanced load rates,with the load-rate difference smaller than 1.5%.展开更多
This study introduces a real-time data-driven battery management scheme designed to address uncertainties in load and generation forecasts,which are integral to an optimal energy storage control system.By expanding on...This study introduces a real-time data-driven battery management scheme designed to address uncertainties in load and generation forecasts,which are integral to an optimal energy storage control system.By expanding on an existing algorithm,this study resolves issues discovered during implementation and addresses previously overlooked concerns,resulting in significant enhancements in both performance and reliability.The refined real-time control scheme is integrated with a day-ahead optimization engine and forecast model,which is utilized for illustrative simulations to highlight its potential efficacy on a real site.Furthermore,a comprehensive comparison with the original formulation was conducted to cover all possible scenarios.This analysis validated the operational effectiveness of the scheme and provided a detailed evaluation of the improvements and expected behavior of the control system.Incorrect or improper adjustments to mitigate forecast uncertainties can result in suboptimal energy management,significant financial losses and penalties,and potential contract violations.The revised algorithm optimizes the operation of the battery system in real time and safeguards its state of health by limiting the charging/discharging cycles and enforcing adherence to contractual agreements.These advancements yield a reliable and efficient real-time correction algorithm for optimal site management,designed as an independent white box that can be integrated with any day-ahead optimization control system.展开更多
The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as diff...The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.展开更多
The prediction and compensation control of marine ship motion is crucial for ensuring the safety of offshore wind turbine loading and unloading operations.However,the accuracy of prediction and control is significantl...The prediction and compensation control of marine ship motion is crucial for ensuring the safety of offshore wind turbine loading and unloading operations.However,the accuracy of prediction and control is significantly affected by the hysteresis phenomenon in the wave compensation system.To address this issue,a ship heave motion prediction is proposed in this paper on the basis of the Gauss-DeepAR(AR stands for autoregressive recurrent)model and the Hilbert−Huang time-delay compensation control strategy.Initially,the zero upward traveling wave period of the level 4−6 sea state ship heave motion is analyzed,which serves as the input sliding window for the Gauss-DeepAR prediction model,and probability predictions at different wave direction angles are conducted.Next,considering the hysteresis characteristics of the ship heave motion compensation platform,the Hilbert−Huang transform is employed to analyze and calculate the hysteresis delay of the compensation platform.After the optimal control action value is subsequently calculated,simulations and hardware platform tests are conducted.The simulation results demonstrated that the Gauss-DeepAR model outperforms autoregressive integrated moving average model(ARIMA),support vector machine(SVM),and longshort-term memory(LSTM)in predicting non-independent identically distributed datasets at a 90°wave direction angle in the level 4−6 sea states.Furthermore,the model has good predictive performance and generalizability for non-independent and non-uniformly distributed datasets at a 180°wave direction angle.The hardware platform compensation test results revealed that the Hilbert–Huang method has an outstanding effect on determining the hysteretic delay and selecting the optimal control action value,and the compensation efficiency was higher than 90%in the level 4−6 sea states.展开更多
Aeropropulsion System Test Facility (ASTF) is required to accurately control the pressure and temperature of the airflow to test the performance of the aero-engine. However, the control accuracy of ASTF is significant...Aeropropulsion System Test Facility (ASTF) is required to accurately control the pressure and temperature of the airflow to test the performance of the aero-engine. However, the control accuracy of ASTF is significantly affected by the flow disturbance caused by aero-engine acceleration and deceleration. This would reduce the credibility of ASTF’s test results for the aero-engine. Therefore, first, this paper proposes a feedforward compensation-based L1 adaptive control method for ASTF to address this problem. The baseline controller is first designed based on ideal uncoupled closed-loop dynamics to achieve dynamic decoupling. Then, L1 adaptive control is adopted to deal with various uncertainties and ensure good control performance. To further enhance the anti-disturbance performance, a feedforward strategy based on disturbance prediction is designed in the L1 adaptive control framework to compensate for the unmatched flow disturbance, which cannot be measured directly. In addition, this strategy takes into account the effects of actuator dynamics. With this method, the feedforward term can be determined from the nominal model parameters despite uncertainties. Finally, to demonstrate the effectiveness of the proposed method, various comparative experiments are performed on a hardware-in-the-loop system of ASTF. The experimental results show that the proposed method possesses excellent tracking performance, anti-disturbance performance and robustness.展开更多
During the excavation and support process in deep soft rocks,complex conditions such as high stress and strong disturbance can be encountered.The complex conditions can cause failure of the support system.Aiming at st...During the excavation and support process in deep soft rocks,complex conditions such as high stress and strong disturbance can be encountered.The complex conditions can cause failure of the support system.Aiming at stability control in deep soft rocks,we proposed the excavation compensation theory.A new high strength and high toughness material was developed.The breaking load and elongation of the new material are 1.59 and 1.78 times that of common bolt materials.To overcome the problem that the CABLE element in FLAC^(3D) cannot simulate failure of support structures,the numerical model for the whole process of force-breaking-anchorage failure simulation(FBAS)for bolts(cables)was established.The numerical experiments on the excavation compensation control of deep soft rock were carried out.The excavation compensation control mechanism of high strength and high toughness material was clarified.Compared with the common support scheme,the highly prestressed support has a maximum increase of 90.24%in radial stress compensation rate and a maximum increase of 67.85%in deformation control rate.The results illustrate the rationality of the excavation compensation theory.The compensation design method of excavations in deep soft rocks was proposed and applied in a deep soft rock chamber.The monitoring indicated that the maximum surrounding rock deformation is 180 mm,reduced by 64%compared to the common support.The deformation of the chamber was controlled and the surrounding rock was stable.展开更多
Through analysis on the background to develop eco-tourism and necessity for ecological compensation,based on specific condition of Hukou County,in line with the situation to develop eco-tourism during ecological water...Through analysis on the background to develop eco-tourism and necessity for ecological compensation,based on specific condition of Hukou County,in line with the situation to develop eco-tourism during ecological water control project of Poyang Lake,residents' interest protection system and ecological benefit safeguard system for eco-tourism compensation were put forward.展开更多
A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range o...A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range of 80dB while using a single variable-gain stage. Temperature-compensation and decibel-linear gain characteristic are achieved by using a control circuit that provides a gain error lower than ±1.5dB over the full temperature and gain ranges. Realized in 0.25μm CMOS technology, a prototype of the proposed VGA provides a total gain range of 64.5dB with 55.6dB-linear range,a P-1dB varying from - 17.5 to 11.5dBm,and a 3dB-bandwith varying from 65 to 860MHz while dissipating 16.5mW from a 2.5V supply voltage.展开更多
Aim Aiming at the position tracking control for valve controlled motor electrohydraulic proportional servo systems mainly driving the static load torque, the tracking performance was studied in the presence of the v...Aim Aiming at the position tracking control for valve controlled motor electrohydraulic proportional servo systems mainly driving the static load torque, the tracking performance was studied in the presence of the variable gain and deadzone. Methods On the basis of conventional composite control with the deadzone compensation method, a comprehensive control approach with the deadzone and self adjusting feedforward compensation was proposed. Results Experimental results showed that the good tracking performance was achieved for the sinusoidal and constant velocity position tracking under a wide variations of load torque. Conclusion The position tracking accuracy for valve controlled motor electrohydraulic proportional servo systems has been solved by using the comprehensive control approach with the deadzone and self adjusting feedforward compensation.展开更多
In order to investigate the joint torque-based Cartesian impedance control strategies and the influence of compensations for friction, an experimental study on the identification of friction parameters, friction compe...In order to investigate the joint torque-based Cartesian impedance control strategies and the influence of compensations for friction, an experimental study on the identification of friction parameters, friction compensation and the Cartesian impedance control are developed for the harmonic drive robot, by using the sensors available in the joint itself. Different from the conventional Cartesian impedance control schemes which are mostly based on the robot end force/torque information, five joint torque-based Cartesian impedance control schemes are considered, including the force-based schemes in Cartesian/joint space, the position-based schemes in Cartesian/joint space and the stiffness control. Four of them are verified by corresponding experiments with/without friction compensations. By comparison, it is found that the force-based impedance control strategy is more suitable than the position-based one for the robot based on joint torque feedback and the friction has even a positive effect on Cartesian impedance control stability.展开更多
A point to? point positioning control of systems with highly nonlinear frictions is studied. In view of variable frictions caused by the changes of load torque, an experimental comparison was made between the valve?...A point to? point positioning control of systems with highly nonlinear frictions is studied. In view of variable frictions caused by the changes of load torque, an experimental comparison was made between the valve? controlled hydraulic motor servo system with PID control and that with friction compensation control. Experimental results show that the gross steady errors are caused by frictions when the system is controlled by the conventional proportional control algorithm. Although the errors can be reduced by introducing the integral control, the limit cycle oscillation and the long setting time are caused. The positioning error for a constant load torque can be eliminated by using fixed friction compensation, but poor positioning accuracy is caused by the same fixed friction compensation when the load torques varies greatly. The dynamic friction compensation based on the error and change in error measurements can significantly improve the position precision in a broad range of the changes of load torque.展开更多
This paper studies a robust adaptive compensation Fault Tolerant Control(FTC)for the medium-scale Unmanned Autonomous Helicopter(UAH)in the presence of external disturbances,actuator faults and input saturation.To imp...This paper studies a robust adaptive compensation Fault Tolerant Control(FTC)for the medium-scale Unmanned Autonomous Helicopter(UAH)in the presence of external disturbances,actuator faults and input saturation.To improve the disturbance rejection capacity of the UAH system in actuator healthy case,an adaptive control method is adopted to cope with the external disturbances and a nominal controller is proposed to stabilize the system.Meanwhile,compensation control inputs are designed to reduce the negative effects derived from actuator faults and input saturation.Based on the backstepping control and inner-outer loop control technologies,a robust adaptive FTC scheme is developed to guarantee the tracking errors convergence.Under the presented FTC controller,the uniform ultimate boundedness of all closed-loop signals is ensured via Lyapunov stability analysis.Simulation results demonstrate the effectiveness of the proposed control algorithm.展开更多
Low-velocity tracking capability is a key performance of flight motion simulator （FMS）, which is mainly affected by the nonlinear friction force. Though many compensation schemes with ad hoc friction models have bee...Low-velocity tracking capability is a key performance of flight motion simulator （FMS）, which is mainly affected by the nonlinear friction force. Though many compensation schemes with ad hoc friction models have been proposed, this paper deals with low-velocity control without friction model, since it is easy to be implemented in practice. Firstly, a nonlinear model of the FMS middle frame, which is driven by a hydraulic rotary actuator, is built. Noting that in the low velocity region, the unmodeled friction force is mainly characterized by a changing-slowly part, thus a simple adaptive law can be employed to learn this changing-slowly part and compensate it. To guarantee the boundedness of adaptation process, a discontinuous projection is utilized and then a robust scheme is proposed. The controller achieves a prescribed output tracking transient performance and final tracking accuracy in general while obtaining asymptotic output tracking in the absence of modeling errors. In addition, a saturated projection adaptive scheme is proposed to improve the globally learning capability when the velocity becomes large, which might make the previous proposed projection-based adaptive law be unstable. Theoretical and extensive experimental results are obtained to verify the high-performance nature of the proposed adaptive robust control strategy.展开更多
The energy-saving electrohydraulic flow matching （EFM） system opens up an opportunity to minimize valve losses by fully opening the control valves, but the controllability is lost under overrunning load conditions. ...The energy-saving electrohydraulic flow matching （EFM） system opens up an opportunity to minimize valve losses by fully opening the control valves, but the controllability is lost under overrunning load conditions. To address this issue, this paper proposes a valve-based compensator to improve the controllability of the energy-saving EFM system. The valve-based compensator consists of a static compensator and a differential dynamic compensator based on load conditions. The energy effi- ciency, the stability performance, and the damping characteristic are analyzed under different control parameters. A parameter selection method is used to improve the efficiency, ensure the stability performance, and obtain good dynamic behavior. A test rig with a 2-t hydraulic excavator is built, and experimental tests are carried out to validate the proposed valve-based compensator. The experimental results indicate that the controllability of the EFM system is improved, and the characteristic of high energy efficiency is obtained by the proposed compensator.展开更多
Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit(HDU),and the contacting between the robot foot end and the ground is complex and variable,which increases the difficulty of force con...Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit(HDU),and the contacting between the robot foot end and the ground is complex and variable,which increases the difficulty of force control inevitably.In the recent years,although many scholars researched some control methods such as disturbance rejection control,parameter self-adaptive control,impedance control and so on,to improve the force control performance of HDU,the robustness of the force control still needs improving.Therefore,how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper.The force control system mathematic model of HDU is established by the mechanism modeling method,and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived,considering the dynamic characteristics of the load stiffness and the load damping under different environment structures.Then,simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform,which provides the foundation for the force control compensation experiment research.In addition,the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping,under which the force control compensation method is introduced,and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment.The research results indicate that if the load characteristics are known,the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation,i.e.,this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters,thereby,the online PID parameters tuning control method which is complex needs not be adopted.All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness.展开更多
The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n tim...The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n time state vector. An estimating algorithm, is developed from this to solve the problem of active control with time delay compensation. The estimating algorithm based on this high order single step β method (HSM) foundation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control with time delay compensation.展开更多
Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation f...Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.展开更多
In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite...In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite element simulation is an e ective method to predict the springback of complex shape parts, but its precision is sensitive to the simulation model, particularly material model and boundary conditions. In this paper, the simple iterative method is introduced to establish the iterative compensation algorithm, and the convergence criterion of iterative parameters is put forward. In addition, the new algorithm is applied to the V-free bending and stretch-bending processes, and the convergence of curvature and bending angle is proved theoretically and verified experimentally. At the same time,the iterative compensation experiments for plane bending show that, the new method can predict the next compensaantido tnh ev atlaureg ebta cseurdv oatnu trhe ew sitphri tnhgeb earcrko ro fo fe laecshs ttehsat,n s0 o. 5 th%a ta rteh eo btatraigneet db aefntedri n2 g-3 a nitgelrea tiwoitnhs.t Thhei se rrreosre aorf clhe sps rtohpaons e±s 0 a.1%new iterative compensation algorithm to predict springback in sheet metal forming process, where each compensation value depends only on the iteration parameter di erence before and after springback for the same forming process of same material.展开更多
There are two kinds of unbalance vibrations—force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings(AMB)system.And two unbalance compensation methods—close...There are two kinds of unbalance vibrations—force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings(AMB)system.And two unbalance compensation methods—closed-loop feedback and open loop feed-forward are presented to reduce the force vibration.The transfer function order of the control system directly influencing the system stability will be increased when the closed-loop method is adopted,which makes the real-time compensation not easily achieved.While the open loop method would not increase the primary transfer function order,it provides conditions for real-time compensation.But the real-time compensation signals are not easy to be obtained in the open loop method.To implement real-time force compensation,a new method is proposed to reduce the force vibration caused by the rotor unbalance on the basis of AMB active control.The method realizes real-time and on-line force auto-compensation based on H∞controller and one novel feed-forward compensation controller,which makes the rotor rotate around its inertia axis.The time-variable feed-forward compensatory signal is provided by a modified adaptive variable step-size least mean square(VSLMS)algorithm.And the relevant least mean square(LMS)algorithm parameters are used to solve the H∞controller weighting functions.The simulation of the new method to compensate some frequency-variable and sinusoidal signals is completed by MATLAB programming,and real-time compensation is implemented in the actual AMB experimental system.The simulation and experiment results show that the compensation scheme can improve the robust stability and the anti-interference ability of the whole AMB system by using H∞controller to achieve close-loop control,and then real-time force unbalance compensation is implemented.The proposed research provides a new control strategy containing real-time algorithm and H∞controller for the force compensation of AMB system.And the stability of the control system is finally improved.展开更多
基金supported in part by the Open Fund of State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment,Guangdong University of Technology(Grant No.JMDZ2021007)in part by the Guangdong International Cooperation Program of Science and Technology(Grant No.2022A0505050078).
文摘Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among the input axes,and coupled linear and angular motions of the end effector.This paper presents an inverse hysteresis-coupling hybrid model to account for such hysteresis and couplings.First,a specially designed kinematic chain is adopted to transfer the pose of the end effector into the linear motions at three prismatic joints.Second,an inverse hysteresis-coupling hybrid model is developed to linearize and decouple the system via a multilayer feedforward neural network.A fractional-order PID controller is also integrated to improve the motion accuracy of the overall system.Experimental results demonstrate that the proposed method can accurately control the motion of the end effector with improved accuracy and robustness.
基金supported by the key technology project of China Southern Power Grid Corporation(GZKJXM20220041)partly by theNational Key Research and Development Plan(2022YFE0205300).
文摘Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper proposes a phase-split power decoupling unbalanced compensation strategy based load balancing strategy for 3P4L based M-LVDC.Firstly,the topology and operation principle of the 3P4L-based M-LVDC system is introduced,and quasi-proportional resonant(QPR)based phase-split power current control for the 3P4L converter is proposed.Secondly,a load-balancing control strategy considering unbalanced compensation for 3P4L-based MLVDC is presented,in which the control diagrams for each 3P4L-based converter are detailed.The core idea of the proposed strategy is to comprehensively consider the imbalance compensation and load rate balancing between the two areas to calculate the split-phase power and current reference values of each 3P4L converter and achieve the static error-free tracking of the reference values through the QPR current inner-loop control.These reference values are then tracked with zero steady-state error using QPR current inner-loop control.Finally,the effectiveness of the proposed control strategy is verified through a 3P4L M-LVDC case study conducted on the PSCAD/EMTDC software.Theresults indicate that the proposed method not only can reduce the three-phase imbalance degrees from>20% to<0.5%,but also achieve excellent balanced load rates,with the load-rate difference smaller than 1.5%.
基金supported by the Israeli Ministry of Infrastructure,Energy and Water Resources.
文摘This study introduces a real-time data-driven battery management scheme designed to address uncertainties in load and generation forecasts,which are integral to an optimal energy storage control system.By expanding on an existing algorithm,this study resolves issues discovered during implementation and addresses previously overlooked concerns,resulting in significant enhancements in both performance and reliability.The refined real-time control scheme is integrated with a day-ahead optimization engine and forecast model,which is utilized for illustrative simulations to highlight its potential efficacy on a real site.Furthermore,a comprehensive comparison with the original formulation was conducted to cover all possible scenarios.This analysis validated the operational effectiveness of the scheme and provided a detailed evaluation of the improvements and expected behavior of the control system.Incorrect or improper adjustments to mitigate forecast uncertainties can result in suboptimal energy management,significant financial losses and penalties,and potential contract violations.The revised algorithm optimizes the operation of the battery system in real time and safeguards its state of health by limiting the charging/discharging cycles and enforcing adherence to contractual agreements.These advancements yield a reliable and efficient real-time correction algorithm for optimal site management,designed as an independent white box that can be integrated with any day-ahead optimization control system.
基金This work described herein was supported by the Program of China Scholarship Council(202206430008)the National Natural Science Foundation of China(NSFC)(52074300 and 52304111)+1 种基金the Yueqi Young Scholars Project of China University of Mining and Technology Beijing(2602021RC84)the Guizhou province science and technology planning project([2020]3007 and[2020]2Y019).
文摘The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.
基金supported by the National Natural Science Foundation of China(Grant No.52105466).
文摘The prediction and compensation control of marine ship motion is crucial for ensuring the safety of offshore wind turbine loading and unloading operations.However,the accuracy of prediction and control is significantly affected by the hysteresis phenomenon in the wave compensation system.To address this issue,a ship heave motion prediction is proposed in this paper on the basis of the Gauss-DeepAR(AR stands for autoregressive recurrent)model and the Hilbert−Huang time-delay compensation control strategy.Initially,the zero upward traveling wave period of the level 4−6 sea state ship heave motion is analyzed,which serves as the input sliding window for the Gauss-DeepAR prediction model,and probability predictions at different wave direction angles are conducted.Next,considering the hysteresis characteristics of the ship heave motion compensation platform,the Hilbert−Huang transform is employed to analyze and calculate the hysteresis delay of the compensation platform.After the optimal control action value is subsequently calculated,simulations and hardware platform tests are conducted.The simulation results demonstrated that the Gauss-DeepAR model outperforms autoregressive integrated moving average model(ARIMA),support vector machine(SVM),and longshort-term memory(LSTM)in predicting non-independent identically distributed datasets at a 90°wave direction angle in the level 4−6 sea states.Furthermore,the model has good predictive performance and generalizability for non-independent and non-uniformly distributed datasets at a 180°wave direction angle.The hardware platform compensation test results revealed that the Hilbert–Huang method has an outstanding effect on determining the hysteretic delay and selecting the optimal control action value,and the compensation efficiency was higher than 90%in the level 4−6 sea states.
基金supported by the“Shuimu Tsinghua Scholar”Project,China(No.2024SM223)the National Science and Technology Major Project,China(No.Y2022-V-0002-0028).
文摘Aeropropulsion System Test Facility (ASTF) is required to accurately control the pressure and temperature of the airflow to test the performance of the aero-engine. However, the control accuracy of ASTF is significantly affected by the flow disturbance caused by aero-engine acceleration and deceleration. This would reduce the credibility of ASTF’s test results for the aero-engine. Therefore, first, this paper proposes a feedforward compensation-based L1 adaptive control method for ASTF to address this problem. The baseline controller is first designed based on ideal uncoupled closed-loop dynamics to achieve dynamic decoupling. Then, L1 adaptive control is adopted to deal with various uncertainties and ensure good control performance. To further enhance the anti-disturbance performance, a feedforward strategy based on disturbance prediction is designed in the L1 adaptive control framework to compensate for the unmatched flow disturbance, which cannot be measured directly. In addition, this strategy takes into account the effects of actuator dynamics. With this method, the feedforward term can be determined from the nominal model parameters despite uncertainties. Finally, to demonstrate the effectiveness of the proposed method, various comparative experiments are performed on a hardware-in-the-loop system of ASTF. The experimental results show that the proposed method possesses excellent tracking performance, anti-disturbance performance and robustness.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3805700)the National Natural Science Foundation of China(Grant No.42277174)the Fundamental Research Funds for the Central Universities,China(Grant No.2024JCCXSB01).
文摘During the excavation and support process in deep soft rocks,complex conditions such as high stress and strong disturbance can be encountered.The complex conditions can cause failure of the support system.Aiming at stability control in deep soft rocks,we proposed the excavation compensation theory.A new high strength and high toughness material was developed.The breaking load and elongation of the new material are 1.59 and 1.78 times that of common bolt materials.To overcome the problem that the CABLE element in FLAC^(3D) cannot simulate failure of support structures,the numerical model for the whole process of force-breaking-anchorage failure simulation(FBAS)for bolts(cables)was established.The numerical experiments on the excavation compensation control of deep soft rock were carried out.The excavation compensation control mechanism of high strength and high toughness material was clarified.Compared with the common support scheme,the highly prestressed support has a maximum increase of 90.24%in radial stress compensation rate and a maximum increase of 67.85%in deformation control rate.The results illustrate the rationality of the excavation compensation theory.The compensation design method of excavations in deep soft rocks was proposed and applied in a deep soft rock chamber.The monitoring indicated that the maximum surrounding rock deformation is 180 mm,reduced by 64%compared to the common support.The deformation of the chamber was controlled and the surrounding rock was stable.
基金Supported by Key Bid Program of Poyang Lake Ecological Economy Research Center of Jiangxi Province(09KJ01)~~
文摘Through analysis on the background to develop eco-tourism and necessity for ecological compensation,based on specific condition of Hukou County,in line with the situation to develop eco-tourism during ecological water control project of Poyang Lake,residents' interest protection system and ecological benefit safeguard system for eco-tourism compensation were put forward.
文摘A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range of 80dB while using a single variable-gain stage. Temperature-compensation and decibel-linear gain characteristic are achieved by using a control circuit that provides a gain error lower than ±1.5dB over the full temperature and gain ranges. Realized in 0.25μm CMOS technology, a prototype of the proposed VGA provides a total gain range of 64.5dB with 55.6dB-linear range,a P-1dB varying from - 17.5 to 11.5dBm,and a 3dB-bandwith varying from 65 to 860MHz while dissipating 16.5mW from a 2.5V supply voltage.
文摘Aim Aiming at the position tracking control for valve controlled motor electrohydraulic proportional servo systems mainly driving the static load torque, the tracking performance was studied in the presence of the variable gain and deadzone. Methods On the basis of conventional composite control with the deadzone compensation method, a comprehensive control approach with the deadzone and self adjusting feedforward compensation was proposed. Results Experimental results showed that the good tracking performance was achieved for the sinusoidal and constant velocity position tracking under a wide variations of load torque. Conclusion The position tracking accuracy for valve controlled motor electrohydraulic proportional servo systems has been solved by using the comprehensive control approach with the deadzone and self adjusting feedforward compensation.
基金The National Natural Science Foundation of China(No.60675045)the National High Technology Research and Development Program of China (863Program) (No.2006AA04Z255)
文摘In order to investigate the joint torque-based Cartesian impedance control strategies and the influence of compensations for friction, an experimental study on the identification of friction parameters, friction compensation and the Cartesian impedance control are developed for the harmonic drive robot, by using the sensors available in the joint itself. Different from the conventional Cartesian impedance control schemes which are mostly based on the robot end force/torque information, five joint torque-based Cartesian impedance control schemes are considered, including the force-based schemes in Cartesian/joint space, the position-based schemes in Cartesian/joint space and the stiffness control. Four of them are verified by corresponding experiments with/without friction compensations. By comparison, it is found that the force-based impedance control strategy is more suitable than the position-based one for the robot based on joint torque feedback and the friction has even a positive effect on Cartesian impedance control stability.
文摘A point to? point positioning control of systems with highly nonlinear frictions is studied. In view of variable frictions caused by the changes of load torque, an experimental comparison was made between the valve? controlled hydraulic motor servo system with PID control and that with friction compensation control. Experimental results show that the gross steady errors are caused by frictions when the system is controlled by the conventional proportional control algorithm. Although the errors can be reduced by introducing the integral control, the limit cycle oscillation and the long setting time are caused. The positioning error for a constant load torque can be eliminated by using fixed friction compensation, but poor positioning accuracy is caused by the same fixed friction compensation when the load torques varies greatly. The dynamic friction compensation based on the error and change in error measurements can significantly improve the position precision in a broad range of the changes of load torque.
基金supported in part by the National Natural Science Foundation of China(Nos.61825302,61573184)in part by the Jiangsu Natural Science Foundation of China(No.BK20171417)in part by the Aeronautical Science Foundation of China(No.20165752049)
文摘This paper studies a robust adaptive compensation Fault Tolerant Control(FTC)for the medium-scale Unmanned Autonomous Helicopter(UAH)in the presence of external disturbances,actuator faults and input saturation.To improve the disturbance rejection capacity of the UAH system in actuator healthy case,an adaptive control method is adopted to cope with the external disturbances and a nominal controller is proposed to stabilize the system.Meanwhile,compensation control inputs are designed to reduce the negative effects derived from actuator faults and input saturation.Based on the backstepping control and inner-outer loop control technologies,a robust adaptive FTC scheme is developed to guarantee the tracking errors convergence.Under the presented FTC controller,the uniform ultimate boundedness of all closed-loop signals is ensured via Lyapunov stability analysis.Simulation results demonstrate the effectiveness of the proposed control algorithm.
文摘Low-velocity tracking capability is a key performance of flight motion simulator （FMS）, which is mainly affected by the nonlinear friction force. Though many compensation schemes with ad hoc friction models have been proposed, this paper deals with low-velocity control without friction model, since it is easy to be implemented in practice. Firstly, a nonlinear model of the FMS middle frame, which is driven by a hydraulic rotary actuator, is built. Noting that in the low velocity region, the unmodeled friction force is mainly characterized by a changing-slowly part, thus a simple adaptive law can be employed to learn this changing-slowly part and compensate it. To guarantee the boundedness of adaptation process, a discontinuous projection is utilized and then a robust scheme is proposed. The controller achieves a prescribed output tracking transient performance and final tracking accuracy in general while obtaining asymptotic output tracking in the absence of modeling errors. In addition, a saturated projection adaptive scheme is proposed to improve the globally learning capability when the velocity becomes large, which might make the previous proposed projection-based adaptive law be unstable. Theoretical and extensive experimental results are obtained to verify the high-performance nature of the proposed adaptive robust control strategy.
基金Project supported by the National Natural Science Foundation of China （No. 51375431）, the Open Fund of the State Key Laboratory of Fluid Power and Mechatronic Systems （No. GZKF-201503）, and the Research Fund of the State Key Laboratory of Mechanical Transmission （No. SKLMT-ZZKT-2015Z10）, China
文摘The energy-saving electrohydraulic flow matching （EFM） system opens up an opportunity to minimize valve losses by fully opening the control valves, but the controllability is lost under overrunning load conditions. To address this issue, this paper proposes a valve-based compensator to improve the controllability of the energy-saving EFM system. The valve-based compensator consists of a static compensator and a differential dynamic compensator based on load conditions. The energy effi- ciency, the stability performance, and the damping characteristic are analyzed under different control parameters. A parameter selection method is used to improve the efficiency, ensure the stability performance, and obtain good dynamic behavior. A test rig with a 2-t hydraulic excavator is built, and experimental tests are carried out to validate the proposed valve-based compensator. The experimental results indicate that the controllability of the EFM system is improved, and the characteristic of high energy efficiency is obtained by the proposed compensator.
基金Supported by National Key Basic Research Program of China(973 Program,Grant No.2014CB046405)State Key Laboratory of Fluid Power and Mechatronic Systems(Zhejiang University)Open Fund Project(Grant No.GZKF-201502)Hebei Military and Civilian Industry Development Funds Projects of China(Grant No.2015B060)
文摘Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit(HDU),and the contacting between the robot foot end and the ground is complex and variable,which increases the difficulty of force control inevitably.In the recent years,although many scholars researched some control methods such as disturbance rejection control,parameter self-adaptive control,impedance control and so on,to improve the force control performance of HDU,the robustness of the force control still needs improving.Therefore,how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper.The force control system mathematic model of HDU is established by the mechanism modeling method,and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived,considering the dynamic characteristics of the load stiffness and the load damping under different environment structures.Then,simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform,which provides the foundation for the force control compensation experiment research.In addition,the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping,under which the force control compensation method is introduced,and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment.The research results indicate that if the load characteristics are known,the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation,i.e.,this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters,thereby,the online PID parameters tuning control method which is complex needs not be adopted.All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness.
文摘The optimal instantaneous high order single step algorithm for active control is first discussed and then, the n+1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of n time state vector. An estimating algorithm, is developed from this to solve the problem of active control with time delay compensation. The estimating algorithm based on this high order single step β method (HSM) foundation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control with time delay compensation.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.N120407007)
文摘Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.
基金Supported by Hebei Provincial Natural Science Foundation of in China(Grant Nos.E2015203244,E2016203266)Program for the Youth Top-notch Talents of Hebei Province
文摘In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite element simulation is an e ective method to predict the springback of complex shape parts, but its precision is sensitive to the simulation model, particularly material model and boundary conditions. In this paper, the simple iterative method is introduced to establish the iterative compensation algorithm, and the convergence criterion of iterative parameters is put forward. In addition, the new algorithm is applied to the V-free bending and stretch-bending processes, and the convergence of curvature and bending angle is proved theoretically and verified experimentally. At the same time,the iterative compensation experiments for plane bending show that, the new method can predict the next compensaantido tnh ev atlaureg ebta cseurdv oatnu trhe ew sitphri tnhgeb earcrko ro fo fe laecshs ttehsat,n s0 o. 5 th%a ta rteh eo btatraigneet db aefntedri n2 g-3 a nitgelrea tiwoitnhs.t Thhei se rrreosre aorf clhe sps rtohpaons e±s 0 a.1%new iterative compensation algorithm to predict springback in sheet metal forming process, where each compensation value depends only on the iteration parameter di erence before and after springback for the same forming process of same material.
基金supported by National Natural Science Foundation of China(Grant No.50437010)National Hi-tech Research and Development Program of China(863Program,Grant No.2006AA05Z205)Project of Six Talented Peak of Jiangsu Province,China(Grant No.07-D-013)
文摘There are two kinds of unbalance vibrations—force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings(AMB)system.And two unbalance compensation methods—closed-loop feedback and open loop feed-forward are presented to reduce the force vibration.The transfer function order of the control system directly influencing the system stability will be increased when the closed-loop method is adopted,which makes the real-time compensation not easily achieved.While the open loop method would not increase the primary transfer function order,it provides conditions for real-time compensation.But the real-time compensation signals are not easy to be obtained in the open loop method.To implement real-time force compensation,a new method is proposed to reduce the force vibration caused by the rotor unbalance on the basis of AMB active control.The method realizes real-time and on-line force auto-compensation based on H∞controller and one novel feed-forward compensation controller,which makes the rotor rotate around its inertia axis.The time-variable feed-forward compensatory signal is provided by a modified adaptive variable step-size least mean square(VSLMS)algorithm.And the relevant least mean square(LMS)algorithm parameters are used to solve the H∞controller weighting functions.The simulation of the new method to compensate some frequency-variable and sinusoidal signals is completed by MATLAB programming,and real-time compensation is implemented in the actual AMB experimental system.The simulation and experiment results show that the compensation scheme can improve the robust stability and the anti-interference ability of the whole AMB system by using H∞controller to achieve close-loop control,and then real-time force unbalance compensation is implemented.The proposed research provides a new control strategy containing real-time algorithm and H∞controller for the force compensation of AMB system.And the stability of the control system is finally improved.
