The trajectory tracking control problem for underactuated unmanned surface vehicles(USV) was addressed, and the control system took account of the uncertain influences induced by model perturbation, external disturban...The trajectory tracking control problem for underactuated unmanned surface vehicles(USV) was addressed, and the control system took account of the uncertain influences induced by model perturbation, external disturbance, etc. By introducing the reference, trajectory was generated by a virtual USV, and the error equation of trajectory tracking for USV was obtained, which transformed the tracking problem of underactuated USV into the stabilization problem of the trajectory tracking error equation. A backstepping adaptive sliding mode controller was proposed based on backstepping technology and method of dynamic slide model control. By means of theoretical analysis, it is proved that the proposed controller ensures that the solutions of closed loop system have the ultimate boundedness property. Simulation results are presented to illustrate the effectiveness of the proposed controller.展开更多
In order to solve the problem of trajectory tracking for a class of novel serial-parallel hybrid humanoid arm（HHA）, which has parameters uncertainty, frictions, disturbance, abrasion and pulse forces derived from mo...In order to solve the problem of trajectory tracking for a class of novel serial-parallel hybrid humanoid arm（HHA）, which has parameters uncertainty, frictions, disturbance, abrasion and pulse forces derived from motors, a multistep dynamics modeling strategy is proposed and a robust controller based on neural network（NN）-adaptive algorithm is designed. At the first step of dynamics modeling, the dynamics model of the reduced HHA is established by Lagrange method. At the second step of dynamics modeling, the parameter uncertain part resulting mainly from the idealization of the HHA is learned by adaptive algorithm. In the trajectory tracking controller, the radial basis function（RBF） NN, whose optimal weights are learned online by adaptive algorithm, is used to learn the upper limit function of the total uncertainties including frictions, disturbances, abrasion and pulse forces. To a great extent, the conservatism of this robust trajectory tracking controller is reduced, and by this controller the HHA can impersonate mostly human actions. The proof and simulation results testify the validity of the adaptive strategy for parameter learning and the neural network-adaptive strategy for the trajectory tracking control.展开更多
An inverse dynamic model is deve1oped through further deduction from the dynamic model of a flexible arm based upon the lagrangian formula,and a dynamic non-linear tracking control scheme,which combines an inverse dyn...An inverse dynamic model is deve1oped through further deduction from the dynamic model of a flexible arm based upon the lagrangian formula,and a dynamic non-linear tracking control scheme,which combines an inverse dynamic method with PD control and non-linear compensator,is proposed for flexible arms.Simulation reaults show this non-linear control scheme can put the flexible arm system under effective control and realize accurate trajectory tracking.展开更多
This paper presents a two-wheeled differential spherical mobile robot in view of the problems that the motion of spherical robot is difficult to control and the sensor is limited by the spherical shell.The robot is si...This paper presents a two-wheeled differential spherical mobile robot in view of the problems that the motion of spherical robot is difficult to control and the sensor is limited by the spherical shell.The robot is simple in structure,flexible in motion and easy to control.The kinematics and dynamics model of spherical mobile robot is established according to the structure of spherical mobile robot.On the basis of the adaptive neural sliding mode control,the trajectory tracking controller of the system is designed.During the simulation of the s-trajectory and circular trajectory tracking control of the spherical mobile robot,it is concluded that the spherical mobile robot is flexible in motion and easy to control.In addition,the simulation results show that the adaptive neural sliding mode control can effectively track the trajectory of the spherical robot.The adaptive control eliminates the influence of unknown parameters and disturbances,and avoids the jitter of left and right wheels during the torque output.展开更多
In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let ...In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let the stability of the internal dynamics depend on that of redefined output, thus we only need to consider the new external dynamics rather than internal dynamics in the process of designing control law. To overcome the explosion of complexity problem in traditional backstepping design, the dynamic surface control(DSC) method is firstly used to deal with the problem of tracking control for the nonlinear non-minimum phase systems. The proposed outputfeedback DSC controller not only forces the system output to asymptotically track the desired trajectory, but also drives the unstable internal dynamics to follow its corresponding bounded and causal ideal internal dynamics, which is solved via stable system center method. Simulation results illustrate the validity of the proposed output-feedback DSC controller.展开更多
In this article,we study the trajectory planning and tracking control of a bionic underwater robot under multiple dynamic obstacles.We first introduce the design of the bionic leopard cabinet underwater robot develope...In this article,we study the trajectory planning and tracking control of a bionic underwater robot under multiple dynamic obstacles.We first introduce the design of the bionic leopard cabinet underwater robot developed in our lab.Then,we model the trajectory planning problem of the bionic underwater robot by combining its dynamics and physical constraints.Furthermore,we conduct global trajectory planning for bionic underwater robots based on the temporal-spatial Bezier curves.In addition,based on the improved proximal policy optimization,local dynamic obstacle avoidance trajectory replanning is carried out.In addition,we design the fuzzy proportional-integral-derivative controller for tracking control of the planned trajectory.Finally,the effectiveness of the real-time trajectory planning and tracking control method is verified by comparative simulation in dynamic environment and semiphysical simulation of UWSim.Among them,the real-time trajectory planning method has advantages in trajectory length,trajectory smoothness,and planning time.The error of trajectory tracking control method is controlled around 0.2 m.展开更多
To address the nonlinearities and external disturbances in unstructured and complex agricultural environments,this paper investigates an autonomous trajectory tracking control method for agricultural ground vehicles.F...To address the nonlinearities and external disturbances in unstructured and complex agricultural environments,this paper investigates an autonomous trajectory tracking control method for agricultural ground vehicles.Firstly,this paper presents the design and implementation of a lightweight,modular two-wheeled differential drive vehicle equipped with two drive wheels and two caster wheels.The vehicle comprises drive wheel modules,passive wheel modules,battery modules,a vehicle frame,a sensor system,and a control system.Secondly,a novel robust trajectory tracking method was proposed,utilizing an improved pure pursuit algorithm.Additionally,an Online Particle Swarm Optimization Continuously Tuned PID(OPSO-CTPID)controller was introduced to dynamically search for optimal control gains for the PID controller.Simulation results demonstrate the superiority of the improved pure pursuit algorithm and the OPSO-CTPID control strategy.To validate the performance,the vehicle was integrated with a seeding and fertilizing machine to realize autonomous wheat seeding in an agricultural environment.Experimental outcomes reveal that the vehicle of this study completed a seeding operation exceeding 1 km in distance.The proposed method can robustly and smoothly track the desired trajectory with an accuracy of less than 10 cm for the root mean square error(RMSE)of the curve and straight lines,given a suitable set of parameters,meeting the requirements of agricultural applications.The findings of this study hold significant reference value for subsequent research on trajectory tracking algorithms for ground-based agricultural robots.展开更多
Small bodies have the characteristics of noncooperative,irregular gravity,and complex terrain on the surface,which cause difficulties in successful landing for conventional landers.In this paper,a multinode flexible l...Small bodies have the characteristics of noncooperative,irregular gravity,and complex terrain on the surface,which cause difficulties in successful landing for conventional landers.In this paper,a multinode flexible lander is put forward to address the problem.The dynamics of this new lander are constructed based on the port-Hamilton framework.The trajectory-tracking formation controller for the lander is designed in a passive way.The proposed dynamics and controller are further validated through numerical simulations.This research presents a fresh concept that holds inspiration for future design involving small-body landers.展开更多
This article presents a general formulation for the mathematical modeling of a specific class of aerial robots known as hexacopters.The mentioned robotic system,which consists of six arms with motors attached to each ...This article presents a general formulation for the mathematical modeling of a specific class of aerial robots known as hexacopters.The mentioned robotic system,which consists of six arms with motors attached to each end,possesses a unique feature:it uses the minimum actuator required to reach a specific position in space with a defined orientation.To achieve this,it is vital to install the motors with an appropriate arrangement positioned at the end of each arm to ensure the robot’s controllability.On the other hand,two virtual arms with zero lengths were used to describe the robot’s orientation with regard to the inertial coordinate system in a tangible manner.One of the innovations carried out in this article is the standardization of the derivation of the motion equations of this robotic system procedure.For this purpose,first,the platform of the hexacopter is separated into several substructures.Following the previous step,the dynamic equations of each of these infrastructures are extracted in explicit form accordingly.Finally,the symbolic equations are merged,and as a result,the dynamic behavior of this aerial robot is formulated.The focus of this research is mainly on hexacopters.However,the presented method is generic enough to cover all aerial robots of this kind(with any number of arms and any relative arrangement between the members).Lastly,to show the robot’s ability to reach a specific position in space with the desired orientation,the results of tracking a relatively complex trajectory by utilizing this robotic system are presented.展开更多
基金Project(51409061)supported by the National Natural Science Foundation of ChinaProject(2013M540271)supported by China Postdoctoral Science Foundation+1 种基金Project(LBH-Z13055)Supported by Heilongjiang Postdoctoral Financial Assistance,ChinaProject(HEUCFD1403)supported by Basic Research Foundation of Central Universities,China
文摘The trajectory tracking control problem for underactuated unmanned surface vehicles(USV) was addressed, and the control system took account of the uncertain influences induced by model perturbation, external disturbance, etc. By introducing the reference, trajectory was generated by a virtual USV, and the error equation of trajectory tracking for USV was obtained, which transformed the tracking problem of underactuated USV into the stabilization problem of the trajectory tracking error equation. A backstepping adaptive sliding mode controller was proposed based on backstepping technology and method of dynamic slide model control. By means of theoretical analysis, it is proved that the proposed controller ensures that the solutions of closed loop system have the ultimate boundedness property. Simulation results are presented to illustrate the effectiveness of the proposed controller.
基金supported by National Basic Research and Development Program of China (973 Program, Grant No. 2006CB705402)
文摘In order to solve the problem of trajectory tracking for a class of novel serial-parallel hybrid humanoid arm（HHA）, which has parameters uncertainty, frictions, disturbance, abrasion and pulse forces derived from motors, a multistep dynamics modeling strategy is proposed and a robust controller based on neural network（NN）-adaptive algorithm is designed. At the first step of dynamics modeling, the dynamics model of the reduced HHA is established by Lagrange method. At the second step of dynamics modeling, the parameter uncertain part resulting mainly from the idealization of the HHA is learned by adaptive algorithm. In the trajectory tracking controller, the radial basis function（RBF） NN, whose optimal weights are learned online by adaptive algorithm, is used to learn the upper limit function of the total uncertainties including frictions, disturbances, abrasion and pulse forces. To a great extent, the conservatism of this robust trajectory tracking controller is reduced, and by this controller the HHA can impersonate mostly human actions. The proof and simulation results testify the validity of the adaptive strategy for parameter learning and the neural network-adaptive strategy for the trajectory tracking control.
文摘An inverse dynamic model is deve1oped through further deduction from the dynamic model of a flexible arm based upon the lagrangian formula,and a dynamic non-linear tracking control scheme,which combines an inverse dynamic method with PD control and non-linear compensator,is proposed for flexible arms.Simulation reaults show this non-linear control scheme can put the flexible arm system under effective control and realize accurate trajectory tracking.
基金Foundation items:National Science and Technology Major Project(No.2011ZX05021-001)China Postdoctoral Science Foundation(No.2019M663865)。
文摘This paper presents a two-wheeled differential spherical mobile robot in view of the problems that the motion of spherical robot is difficult to control and the sensor is limited by the spherical shell.The robot is simple in structure,flexible in motion and easy to control.The kinematics and dynamics model of spherical mobile robot is established according to the structure of spherical mobile robot.On the basis of the adaptive neural sliding mode control,the trajectory tracking controller of the system is designed.During the simulation of the s-trajectory and circular trajectory tracking control of the spherical mobile robot,it is concluded that the spherical mobile robot is flexible in motion and easy to control.In addition,the simulation results show that the adaptive neural sliding mode control can effectively track the trajectory of the spherical robot.The adaptive control eliminates the influence of unknown parameters and disturbances,and avoids the jitter of left and right wheels during the torque output.
基金supported by National Natural Science Foundation of China(61403013)the Aero-Science Foundation of China(2015ZA51009)
文摘In this paper, an output-feedback tracking controller is proposed for a class of nonlinear non-minimum phase systems.To keep the unstable internal dynamics bounded, the method of output redefinition is applied to let the stability of the internal dynamics depend on that of redefined output, thus we only need to consider the new external dynamics rather than internal dynamics in the process of designing control law. To overcome the explosion of complexity problem in traditional backstepping design, the dynamic surface control(DSC) method is firstly used to deal with the problem of tracking control for the nonlinear non-minimum phase systems. The proposed outputfeedback DSC controller not only forces the system output to asymptotically track the desired trajectory, but also drives the unstable internal dynamics to follow its corresponding bounded and causal ideal internal dynamics, which is solved via stable system center method. Simulation results illustrate the validity of the proposed output-feedback DSC controller.
基金supported in part by the STI 2030-Major Projects under Grant 2021ZD0114504in part by the National Natural Science Foundation of China under Grants 62276253 and 62203435in part by the Beijing Nova Program under Grants Z211100002121152 and 20230484457.
文摘In this article,we study the trajectory planning and tracking control of a bionic underwater robot under multiple dynamic obstacles.We first introduce the design of the bionic leopard cabinet underwater robot developed in our lab.Then,we model the trajectory planning problem of the bionic underwater robot by combining its dynamics and physical constraints.Furthermore,we conduct global trajectory planning for bionic underwater robots based on the temporal-spatial Bezier curves.In addition,based on the improved proximal policy optimization,local dynamic obstacle avoidance trajectory replanning is carried out.In addition,we design the fuzzy proportional-integral-derivative controller for tracking control of the planned trajectory.Finally,the effectiveness of the real-time trajectory planning and tracking control method is verified by comparative simulation in dynamic environment and semiphysical simulation of UWSim.Among them,the real-time trajectory planning method has advantages in trajectory length,trajectory smoothness,and planning time.The error of trajectory tracking control method is controlled around 0.2 m.
基金Jiangsu Provincial Key Research and Development Program(Grant No.BE2017301)Jiangsu Provincial Key Research and Development Program(Grant No.BE2022363)+2 种基金Project of Jiangsu Modern Agricultural Machinery Equipment&Technology Demonstration and Promotion(Grant No.NJ2022-03)National Natural Science Fund of China(Grant No.61473155)Six Talent Peaks Project in Jiangsu Province of China(Grant No.GDZB-039).
文摘To address the nonlinearities and external disturbances in unstructured and complex agricultural environments,this paper investigates an autonomous trajectory tracking control method for agricultural ground vehicles.Firstly,this paper presents the design and implementation of a lightweight,modular two-wheeled differential drive vehicle equipped with two drive wheels and two caster wheels.The vehicle comprises drive wheel modules,passive wheel modules,battery modules,a vehicle frame,a sensor system,and a control system.Secondly,a novel robust trajectory tracking method was proposed,utilizing an improved pure pursuit algorithm.Additionally,an Online Particle Swarm Optimization Continuously Tuned PID(OPSO-CTPID)controller was introduced to dynamically search for optimal control gains for the PID controller.Simulation results demonstrate the superiority of the improved pure pursuit algorithm and the OPSO-CTPID control strategy.To validate the performance,the vehicle was integrated with a seeding and fertilizing machine to realize autonomous wheat seeding in an agricultural environment.Experimental outcomes reveal that the vehicle of this study completed a seeding operation exceeding 1 km in distance.The proposed method can robustly and smoothly track the desired trajectory with an accuracy of less than 10 cm for the root mean square error(RMSE)of the curve and straight lines,given a suitable set of parameters,meeting the requirements of agricultural applications.The findings of this study hold significant reference value for subsequent research on trajectory tracking algorithms for ground-based agricultural robots.
基金supported by the National Key R&D Program(grant number 2019YFA0706500)the National Natural Science Foundation of China(grant number 62273118)National defense basic research projects(grant numbers JCKY2021603B030,JCKY2020903B002).
文摘Small bodies have the characteristics of noncooperative,irregular gravity,and complex terrain on the surface,which cause difficulties in successful landing for conventional landers.In this paper,a multinode flexible lander is put forward to address the problem.The dynamics of this new lander are constructed based on the port-Hamilton framework.The trajectory-tracking formation controller for the lander is designed in a passive way.The proposed dynamics and controller are further validated through numerical simulations.This research presents a fresh concept that holds inspiration for future design involving small-body landers.
文摘This article presents a general formulation for the mathematical modeling of a specific class of aerial robots known as hexacopters.The mentioned robotic system,which consists of six arms with motors attached to each end,possesses a unique feature:it uses the minimum actuator required to reach a specific position in space with a defined orientation.To achieve this,it is vital to install the motors with an appropriate arrangement positioned at the end of each arm to ensure the robot’s controllability.On the other hand,two virtual arms with zero lengths were used to describe the robot’s orientation with regard to the inertial coordinate system in a tangible manner.One of the innovations carried out in this article is the standardization of the derivation of the motion equations of this robotic system procedure.For this purpose,first,the platform of the hexacopter is separated into several substructures.Following the previous step,the dynamic equations of each of these infrastructures are extracted in explicit form accordingly.Finally,the symbolic equations are merged,and as a result,the dynamic behavior of this aerial robot is formulated.The focus of this research is mainly on hexacopters.However,the presented method is generic enough to cover all aerial robots of this kind(with any number of arms and any relative arrangement between the members).Lastly,to show the robot’s ability to reach a specific position in space with the desired orientation,the results of tracking a relatively complex trajectory by utilizing this robotic system are presented.
