Underwater cleaning robots face significant challenges from external disturbances, including waves, currents, surface contact forces, and reaction forces from cleaning equipment. These disturbances compromise trajecto...Underwater cleaning robots face significant challenges from external disturbances, including waves, currents, surface contact forces, and reaction forces from cleaning equipment. These disturbances compromise trajectory-tracking accuracy and destabilize attachment force control, consequently diminishing cleaning performance. This paper presents a hybrid force/position control method to achieve simultaneous proper force and precise position control of underwater robots under disturbances. Following dynamics modeling and disturbance analysis, the study develops a pose controller utilizing active disturbance rejection control(ADRC) and a force controller employing an adaptive impedance method. An extended state observer(ESO) with gain fuzzy regulation observes and compensates for disturbances, ensuring precise trajectory tracking and stable adhesion force control. The disturbance estimate additionally facilitates online adjustment of the impedance controller's desired force to maintain appropriate adhesion force. Simulation and experimental results validate that the proposed method substantially improves disturbance resistance and motion capabilities, enabling underwater cleaning operations with suitable contact force and high trajectory accuracy.展开更多
Serving the Stewart mechanism as a wheel-legged structure,the most outstanding superiority of the proposed wheel-legged hybrid robot(WLHR)is the active vibration isolation function during rolling on rugged terrain.How...Serving the Stewart mechanism as a wheel-legged structure,the most outstanding superiority of the proposed wheel-legged hybrid robot(WLHR)is the active vibration isolation function during rolling on rugged terrain.However,it is difficult to obtain its precise dynamic model,because of the nonlinearity and uncertainty of the heavy robot.This paper presents a dynamic control framework with a decentralized structure for single wheel-leg,position tracking based on model predictive control(MPC)and adaptive impedance module from inside to outside.Through the Newton-Euler dynamic model of the Stewart mechanism,the controller first creates a predictive model by combining Newton-Raphson iteration of forward kinematic and inverse kinematic calculation of Stewart.The actuating force naturally enables each strut to stretch and retract,thereby realizing six degrees-of-freedom(6-DOFs)position-tracking for Stewart wheel-leg.The adaptive impedance control in the outermost loop adjusts environmental impedance parameters by current position and force feedback of wheel-leg along Z-axis.This adjustment allows the robot to adequately control the desired support force tracking,isolating the robot body from vibration that is generated from unknown terrain.The availability of the proposed control methodology on a physical prototype is demonstrated by tracking a Bezier curve and active vibration isolation while the robot is rolling on decelerate strips.By comparing the proportional and integral(PI)and constant impedance controllers,better performance of the proposed algorithm was operated and evaluated through displacement and force sensors internally-installed in each cylinder,as well as an inertial measurement unit(IMU)mounted on the robot body.The proposed algorithm structure significantly enhances the control accuracy and vibration isolation capacity of parallel wheel-legged robot.展开更多
Precise control of the contact force is crucial in the application of non-wearable defecation smart care(DSC)robot.A deformable shield equipped with a pressure sensing function is designed,with a bending angle that ca...Precise control of the contact force is crucial in the application of non-wearable defecation smart care(DSC)robot.A deformable shield equipped with a pressure sensing function is designed,with a bending angle that can be adjusted according to pressure feedback,thus enabling it to adapt to various body shapes.To improve the force tracking accuracy and prevent obvious force overshoot in the initial contact stage,a contact force control strategy based on fuzzy adaptive variable impedance is proposed.The proposed contact force control strategy achieves an average root-mean-square error of 0.024 and an average overshoot of 1.74%.Experimental results demonstrate that the designed deformable shield can fit the human body well,while the proposed control strategy enhances the contact force management and realizes the precise control of human-robot contact force.展开更多
This paper studies a mirror-assisted rehabilitation training method based on a dual-arm robot,which aims to provide an effective rehabilitation training program for patients with upper limb dysfunction due to stroke o...This paper studies a mirror-assisted rehabilitation training method based on a dual-arm robot,which aims to provide an effective rehabilitation training program for patients with upper limb dysfunction due to stroke or other causes.During the mirror training task scenario,the subjects are visually guided to perform the mirror movement of both arms,and the dual-arm robot is used to facilitate the mirror-assisted rehabilitation from the healthy side to the affected side.Adaptive imped-ance control and force field channel design ensure the stability and safety of the rehabilitation process.In the rehabilitation training,appropriate assistance forces are provided within the channel to correct trajectory deviations,ensuring that the subjects'movement path aligns with the predetermined trajectory.Outside the channel,the superposition of stiffness and correction force fields prevents the subjects from deviating from the predetermined trajectory,thus avoiding injuries.In addition,the adaptive impedance control is capable of dynamically adjusting the impedance parameters according to the real-time state of the subjects,providing a personalized rehabilitation training program.This method significantly enhances both the safety and effectiveness of the rehabilitation training.The experimental results showed that the subjects'motion flexibility and safety were significantly improved during the mirror-assisted rehabilitation training.This study offers a new approach for the future development of rehabilitation robotics with broad application potential.展开更多
In this paper,we present a novel data-driven design method for the human-robot interaction(HRI)system,where a given task is achieved by cooperation between the human and the robot.The presented HRI controller design i...In this paper,we present a novel data-driven design method for the human-robot interaction(HRI)system,where a given task is achieved by cooperation between the human and the robot.The presented HRI controller design is a two-level control design approach consisting of a task-oriented performance optimization design and a plant-oriented impedance controller design.The task-oriented design minimizes the human effort and guarantees the perfect task tracking in the outer-loop,while the plant-oriented achieves the desired impedance from the human to the robot manipulator end-effector in the inner-loop.Data-driven reinforcement learning techniques are used for performance optimization in the outer-loop to assign the optimal impedance parameters.In the inner-loop,a velocity-free filter is designed to avoid the requirement of end-effector velocity measurement.On this basis,an adaptive controller is designed to achieve the desired impedance of the robot manipulator in the task space.The simulation and experiment of a robot manipulator are conducted to verify the efficacy of the presented HRI design framework.展开更多
The effects of nonlinear loads on voltage quality represent an emerging concern for islanded microgrids.Existing research works have mainly focused on harmonic power sharing among multiple inverters,which ignores the ...The effects of nonlinear loads on voltage quality represent an emerging concern for islanded microgrids.Existing research works have mainly focused on harmonic power sharing among multiple inverters,which ignores the diversity of different inverters to mitigate harmonics from nonlinear loads.As a result,the voltage quality of microgrids cannot be effectively improved.To address this issue,this study proposes an adaptive harmonic virtual impedance(HVI)control for improving voltage quality of microgrids.Based on the premise that no inverter is overloaded,the main objective of the proposed control is to maximize harmonic power absorption by shaping the lowest output impedances of inverters.To achieve this,the proposed control is utilized to adjust the HVI of each inverter based on its operation conditions.In addition,the evaluation based on Monte Carlo harmonic power flow is designed to assess the performance of the proposed control in practice.Finally,comparative studies and control-in-the-loop experiments are conducted.展开更多
基金financially supported by the Huzhou Science and Technology Plan Project (Grant No.2023GZ25)the Pioneer Leading Goose+X Science and Technology Program of Zhejiang Province,China (Grant No.2025C02018)the Zhejiang Provincial High-Level Talent Special Support Program-Leading Talents in Technological Innovation (Grant No.2023R5217)。
文摘Underwater cleaning robots face significant challenges from external disturbances, including waves, currents, surface contact forces, and reaction forces from cleaning equipment. These disturbances compromise trajectory-tracking accuracy and destabilize attachment force control, consequently diminishing cleaning performance. This paper presents a hybrid force/position control method to achieve simultaneous proper force and precise position control of underwater robots under disturbances. Following dynamics modeling and disturbance analysis, the study develops a pose controller utilizing active disturbance rejection control(ADRC) and a force controller employing an adaptive impedance method. An extended state observer(ESO) with gain fuzzy regulation observes and compensates for disturbances, ensuring precise trajectory tracking and stable adhesion force control. The disturbance estimate additionally facilitates online adjustment of the impedance controller's desired force to maintain appropriate adhesion force. Simulation and experimental results validate that the proposed method substantially improves disturbance resistance and motion capabilities, enabling underwater cleaning operations with suitable contact force and high trajectory accuracy.
基金Supported by National Natural Science Foundation of China(Grant No.61773060).
文摘Serving the Stewart mechanism as a wheel-legged structure,the most outstanding superiority of the proposed wheel-legged hybrid robot(WLHR)is the active vibration isolation function during rolling on rugged terrain.However,it is difficult to obtain its precise dynamic model,because of the nonlinearity and uncertainty of the heavy robot.This paper presents a dynamic control framework with a decentralized structure for single wheel-leg,position tracking based on model predictive control(MPC)and adaptive impedance module from inside to outside.Through the Newton-Euler dynamic model of the Stewart mechanism,the controller first creates a predictive model by combining Newton-Raphson iteration of forward kinematic and inverse kinematic calculation of Stewart.The actuating force naturally enables each strut to stretch and retract,thereby realizing six degrees-of-freedom(6-DOFs)position-tracking for Stewart wheel-leg.The adaptive impedance control in the outermost loop adjusts environmental impedance parameters by current position and force feedback of wheel-leg along Z-axis.This adjustment allows the robot to adequately control the desired support force tracking,isolating the robot body from vibration that is generated from unknown terrain.The availability of the proposed control methodology on a physical prototype is demonstrated by tracking a Bezier curve and active vibration isolation while the robot is rolling on decelerate strips.By comparing the proportional and integral(PI)and constant impedance controllers,better performance of the proposed algorithm was operated and evaluated through displacement and force sensors internally-installed in each cylinder,as well as an inertial measurement unit(IMU)mounted on the robot body.The proposed algorithm structure significantly enhances the control accuracy and vibration isolation capacity of parallel wheel-legged robot.
基金supported by grants from the National Key R and D Program of China(2022YFB4703300).
文摘Precise control of the contact force is crucial in the application of non-wearable defecation smart care(DSC)robot.A deformable shield equipped with a pressure sensing function is designed,with a bending angle that can be adjusted according to pressure feedback,thus enabling it to adapt to various body shapes.To improve the force tracking accuracy and prevent obvious force overshoot in the initial contact stage,a contact force control strategy based on fuzzy adaptive variable impedance is proposed.The proposed contact force control strategy achieves an average root-mean-square error of 0.024 and an average overshoot of 1.74%.Experimental results demonstrate that the designed deformable shield can fit the human body well,while the proposed control strategy enhances the contact force management and realizes the precise control of human-robot contact force.
基金supported by the Shanghai Municipal Economic and Information Commission(Project No.240404).
文摘This paper studies a mirror-assisted rehabilitation training method based on a dual-arm robot,which aims to provide an effective rehabilitation training program for patients with upper limb dysfunction due to stroke or other causes.During the mirror training task scenario,the subjects are visually guided to perform the mirror movement of both arms,and the dual-arm robot is used to facilitate the mirror-assisted rehabilitation from the healthy side to the affected side.Adaptive imped-ance control and force field channel design ensure the stability and safety of the rehabilitation process.In the rehabilitation training,appropriate assistance forces are provided within the channel to correct trajectory deviations,ensuring that the subjects'movement path aligns with the predetermined trajectory.Outside the channel,the superposition of stiffness and correction force fields prevents the subjects from deviating from the predetermined trajectory,thus avoiding injuries.In addition,the adaptive impedance control is capable of dynamically adjusting the impedance parameters according to the real-time state of the subjects,providing a personalized rehabilitation training program.This method significantly enhances both the safety and effectiveness of the rehabilitation training.The experimental results showed that the subjects'motion flexibility and safety were significantly improved during the mirror-assisted rehabilitation training.This study offers a new approach for the future development of rehabilitation robotics with broad application potential.
基金This work was supported in part by the National Natural Science Foundation of China(61903028)the Youth Innovation Promotion Association,Chinese Academy of Sciences(2020137)+1 种基金the Lifelong Learning Machines Program from DARPA/Microsystems Technology Officethe Army Research Laboratory(W911NF-18-2-0260).
文摘In this paper,we present a novel data-driven design method for the human-robot interaction(HRI)system,where a given task is achieved by cooperation between the human and the robot.The presented HRI controller design is a two-level control design approach consisting of a task-oriented performance optimization design and a plant-oriented impedance controller design.The task-oriented design minimizes the human effort and guarantees the perfect task tracking in the outer-loop,while the plant-oriented achieves the desired impedance from the human to the robot manipulator end-effector in the inner-loop.Data-driven reinforcement learning techniques are used for performance optimization in the outer-loop to assign the optimal impedance parameters.In the inner-loop,a velocity-free filter is designed to avoid the requirement of end-effector velocity measurement.On this basis,an adaptive controller is designed to achieve the desired impedance of the robot manipulator in the task space.The simulation and experiment of a robot manipulator are conducted to verify the efficacy of the presented HRI design framework.
基金supported by the Science and Technology Project of State Grid Corporation of China(No.5400-202219417A-2-0-ZN)。
文摘The effects of nonlinear loads on voltage quality represent an emerging concern for islanded microgrids.Existing research works have mainly focused on harmonic power sharing among multiple inverters,which ignores the diversity of different inverters to mitigate harmonics from nonlinear loads.As a result,the voltage quality of microgrids cannot be effectively improved.To address this issue,this study proposes an adaptive harmonic virtual impedance(HVI)control for improving voltage quality of microgrids.Based on the premise that no inverter is overloaded,the main objective of the proposed control is to maximize harmonic power absorption by shaping the lowest output impedances of inverters.To achieve this,the proposed control is utilized to adjust the HVI of each inverter based on its operation conditions.In addition,the evaluation based on Monte Carlo harmonic power flow is designed to assess the performance of the proposed control in practice.Finally,comparative studies and control-in-the-loop experiments are conducted.
