In this paper,we consider eyes from the human binocular system,that simultaneously gaze on stationary point targets in space,while optimalal skipping from one target to the next,by rotaing their individual gaze drecto...In this paper,we consider eyes from the human binocular system,that simultaneously gaze on stationary point targets in space,while optimalal skipping from one target to the next,by rotaing their individual gaze drecton.The head is assume fixed on the torso and the rotaing gaze direction of the two eyes are assumed restricted to pass through a point in the visual space.It is further assumed that,individullly the rotations of the two eyes satisfy the well known Listing's law.We formulate and study acombined optimal gaze rotation for the two eyes,by constructing a single Riemanmian metric,on the asociaced parameter space.The goal is to optimally rotate so that the convergent gaze changes between two pre-specified target points in a finite time interval[0,1].The cost function we choose is the total energy,measured by the L2?norm,of the six extenal torques on the binocular system.The torque functions are synthesized by solving an associated*two-point boundary value problem.The paper demonstrates,via simulation,the shape of the optimal gaze trajectory of the focused point of the bin-ocular system.The Euclidean distance between the initial and the final point is compared to the arc:length of the optimal trajectory.The consumed energy.is computed for diferent eye movement chores and discussed in the paper.Via simulation we observe that certain eye movement maneuvers are energy fficicnt and demonstrate that the optimal external torque is a linear function in time.We also explore and conclude that spitting an arbitry opimal eye movement into optimal vergence and version components is not energy fficient although this is how the human oculomotor control seems to operate.Opimal gaze tajectories and opimal extermal torque functions reported in this paper is new.展开更多
Both safety and stability are primary performance criteria for multi-unmanned aerial vehicle(multi-UAV)systems in many coordination tasks.Existing approaches often consider safety and stability separately.It is necess...Both safety and stability are primary performance criteria for multi-unmanned aerial vehicle(multi-UAV)systems in many coordination tasks.Existing approaches often consider safety and stability separately.It is necessary and urgent to develop a safety-stability control strategy to merge these two performance criteria.In this paper,a unified approach is developed to consider safety and stability for multi-UAV formation control.The stability criterion is represented by a Lyapunov function and safety criterion is represented by a barrier function and then a relaxed converse control Lyapunov-barrier theorem is obtained.With the help of a relaxed converse control Lyapunov-barrier function(RCCLBF),a distributed safety-stability formation control strategy is proposed for the multi-UAV system.By transforming the solution of RCCLBF to a Lyapunovlike stabilization problem,we show that the proposed formation control strategy can drive the UAVs staying within a specified safe set.Simulation results are provided to validate the proposed safety-stability formation control strategy.展开更多
This paper presents a novel distributed multi-agent temporal-difference learning framework for value function approximation,which alows agents using all the neighbor information instead of the information from only on...This paper presents a novel distributed multi-agent temporal-difference learning framework for value function approximation,which alows agents using all the neighbor information instead of the information from only one neighbor.With full neighbor information,the proposed framework(1)has a faster convergence rate,and(2)is more robust compared to the state of-the art approaches.Then we propose a distributed multi-agent discounted temporal dfferene algorithm and a distributed muli-agent average cost temporal diference leaming algorithm based on th framework.Moreover,the two proposed algorthms'theoretical convergence proofs are provided.Numerical simulation resuts show that our proposed algorihms are superior to the gossip-based algorithm in convergence speed,robustness to noise and time-varying network topology.展开更多
Combining safety objectives with stability objectives is crucial for safety-critical systems.Existing studies generally unified these two objectives by constructing Lyapunov-type barrier functions.However,insufficient...Combining safety objectives with stability objectives is crucial for safety-critical systems.Existing studies generally unified these two objectives by constructing Lyapunov-type barrier functions.However,insufficient analysis of key set relationships within the system may render the proposed safety and stability conditions conservative,and these studies also did not provide how to use such conditions to design safety-stability control strategies.This paper proposed a feasible and constructive design to achieve stabilization of safety-critical systems by a relaxed converse Lyapunov-barrier approach.By analyzing the relationships between a series of sets associated with the safety-critical system,the stability and safety conditions can be appropriately relaxed.Then,with the help of relaxed converse control Lyapunov-barrier functions(RCCLBFs),a theoretical result was obtained for the stability of affine nonlinear systems with safety constraints.Subsequently,a constructive method was developed for a second-order strict-feedback system to transform the process of solving RCCLBFs into a Lyapunov-like stabilization problem.Finally,the proposed safety-stability control method is exerted on a robotic system and demonstrated by simulations.展开更多
文摘In this paper,we consider eyes from the human binocular system,that simultaneously gaze on stationary point targets in space,while optimalal skipping from one target to the next,by rotaing their individual gaze drecton.The head is assume fixed on the torso and the rotaing gaze direction of the two eyes are assumed restricted to pass through a point in the visual space.It is further assumed that,individullly the rotations of the two eyes satisfy the well known Listing's law.We formulate and study acombined optimal gaze rotation for the two eyes,by constructing a single Riemanmian metric,on the asociaced parameter space.The goal is to optimally rotate so that the convergent gaze changes between two pre-specified target points in a finite time interval[0,1].The cost function we choose is the total energy,measured by the L2?norm,of the six extenal torques on the binocular system.The torque functions are synthesized by solving an associated*two-point boundary value problem.The paper demonstrates,via simulation,the shape of the optimal gaze trajectory of the focused point of the bin-ocular system.The Euclidean distance between the initial and the final point is compared to the arc:length of the optimal trajectory.The consumed energy.is computed for diferent eye movement chores and discussed in the paper.Via simulation we observe that certain eye movement maneuvers are energy fficicnt and demonstrate that the optimal external torque is a linear function in time.We also explore and conclude that spitting an arbitry opimal eye movement into optimal vergence and version components is not energy fficient although this is how the human oculomotor control seems to operate.Opimal gaze tajectories and opimal extermal torque functions reported in this paper is new.
基金supported in part by the National Key Research and Development Program of China(No.2022YFE0133100)in part by the National Natural Science Foundation of China(No.62203089)in part by the Sichuan Science and Technology Program(Nos.24NSFSC1362,2020YFSY0012).
文摘Both safety and stability are primary performance criteria for multi-unmanned aerial vehicle(multi-UAV)systems in many coordination tasks.Existing approaches often consider safety and stability separately.It is necessary and urgent to develop a safety-stability control strategy to merge these two performance criteria.In this paper,a unified approach is developed to consider safety and stability for multi-UAV formation control.The stability criterion is represented by a Lyapunov function and safety criterion is represented by a barrier function and then a relaxed converse control Lyapunov-barrier theorem is obtained.With the help of a relaxed converse control Lyapunov-barrier function(RCCLBF),a distributed safety-stability formation control strategy is proposed for the multi-UAV system.By transforming the solution of RCCLBF to a Lyapunovlike stabilization problem,we show that the proposed formation control strategy can drive the UAVs staying within a specified safe set.Simulation results are provided to validate the proposed safety-stability formation control strategy.
基金the Sichuan Science and Technology Program(No.2020YFSY0012)the National Natural Science Foundation of China(Nos.61473061,61104104)the Program for New Century Excellent Talents in University(No.NCET-13-0091).
文摘This paper presents a novel distributed multi-agent temporal-difference learning framework for value function approximation,which alows agents using all the neighbor information instead of the information from only one neighbor.With full neighbor information,the proposed framework(1)has a faster convergence rate,and(2)is more robust compared to the state of-the art approaches.Then we propose a distributed multi-agent discounted temporal dfferene algorithm and a distributed muli-agent average cost temporal diference leaming algorithm based on th framework.Moreover,the two proposed algorthms'theoretical convergence proofs are provided.Numerical simulation resuts show that our proposed algorihms are superior to the gossip-based algorithm in convergence speed,robustness to noise and time-varying network topology.
基金supported by the National Key Research and Development Program of China under Grant No.2022YFE0133100by Sichuan Science and Technology Program under Grant No.2024NSFSC0528.
文摘Combining safety objectives with stability objectives is crucial for safety-critical systems.Existing studies generally unified these two objectives by constructing Lyapunov-type barrier functions.However,insufficient analysis of key set relationships within the system may render the proposed safety and stability conditions conservative,and these studies also did not provide how to use such conditions to design safety-stability control strategies.This paper proposed a feasible and constructive design to achieve stabilization of safety-critical systems by a relaxed converse Lyapunov-barrier approach.By analyzing the relationships between a series of sets associated with the safety-critical system,the stability and safety conditions can be appropriately relaxed.Then,with the help of relaxed converse control Lyapunov-barrier functions(RCCLBFs),a theoretical result was obtained for the stability of affine nonlinear systems with safety constraints.Subsequently,a constructive method was developed for a second-order strict-feedback system to transform the process of solving RCCLBFs into a Lyapunov-like stabilization problem.Finally,the proposed safety-stability control method is exerted on a robotic system and demonstrated by simulations.
