A difficult but important problem in optimal control theory is the design of an optimal feedback control, i.e., the design of an optimal control as function of the phase (state) coordinates [1,2]. This problem can be ...A difficult but important problem in optimal control theory is the design of an optimal feedback control, i.e., the design of an optimal control as function of the phase (state) coordinates [1,2]. This problem can be solved not often. We study here the autonomous nonlinear system of second order in general form. The constraints imposed on the control input can depend on the phase (state) coordinates of the system. The goal of the control is to maximize or minimize one phase coordinate of the considered system while other takes a prescribed in advance value. In the literature, optimal control problems for the systems of second order are most frequently associated with driving both phase coordinates to a prescribed in advance state. In this statement of the problem, the optimal control feedback can be designed only for special kind of systems. In our statement of the problem, an optimal control can be designed as function of the state coordinates for more general kind of the systems. The problem of maximization or minimization of the swing amplitude is considered explicitly as an example. Simulation results are presented.展开更多
Active capsule endoscopy is becoming a research hotspot in recent years. We design an active capsule robot (capsubot) with the vibrational mode. The internal force-static friction control strategy which is used in the...Active capsule endoscopy is becoming a research hotspot in recent years. We design an active capsule robot (capsubot) with the vibrational mode. The internal force-static friction control strategy which is used in the capsubot is effective in rigid environment but not in viscoelastic environment. A particular viscoelastic material whose parameters are confirmed is set to the viscoelastic environment. We suppose that it is a periodic damped oscillation system when the capsubot make a free vibration in the environment. We propose a new control strategy whose principle is similar to a swing in the environment. The simulation results show that the new strategy is effective.展开更多
针对四旋翼无人机吊挂系统的负载摆动抑制和轨迹跟踪问题,提出一种线性自抗扰控制器(Liner Active Disturbance Rejection Controller,LADRC)的轨迹跟踪控制方法。首先,考虑到四旋翼吊挂负载耦合飞行的未知外界扰动与模型的动态不确定性...针对四旋翼无人机吊挂系统的负载摆动抑制和轨迹跟踪问题,提出一种线性自抗扰控制器(Liner Active Disturbance Rejection Controller,LADRC)的轨迹跟踪控制方法。首先,考虑到四旋翼吊挂负载耦合飞行的未知外界扰动与模型的动态不确定性,为飞行器的姿态、位置设计线性自抗扰控制器,通过扩张状态观测器(Extended State Observer,ESO)观测负载摆动和环境干扰对机体的扰动,并对控制量进行相应补偿,来抑制外界和负载摆动给机体带来的干扰,保证无人机飞行过程中的稳定性。其次,针对四旋翼无人机吊挂系统在飞行过程中负载摆角过大的问题,设计加速度规划摆角抑制算法,通过摆角的实时反馈对四旋翼无人机的位置轨迹输入进行路径规划,实现飞行过程中负载摆动的抑制。最后,通过仿真结果证明该控制方法对飞行器的位置及姿态控制效果较好,同时验证了所提的轨迹规划方法能够有效抑制吊挂物的摆动,且对干扰的鲁棒性较强。展开更多
Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by ...Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by PAMs.A 3-DOF musculoskeletal bionic leg mechanism is presented,which is driven by PAMs for quadruped robots.PAM is used to simulate the compliance of biological muscle.The kinematics of the leg swing is derived,and the foot desired trajectory is planned as the sinusoidal functions.The swing experiments of the musculoskeletal leg mechanism are conducted to analyse the extension and flexion of joints.A proportional integral derivative(PID) algorithm is presented for controlling the flexion/extension of the joint.The trajectory tracking results of joints and the PAM gas pressure are obtained.Experimental results show that the developed leg mechanism exhibits good biological properties.展开更多
随着具备频率调节功能的风电机组大规模并网,其调频控制严重影响了电力系统暂态功角的稳定性。文章以送端区域接入风机且联络线中间节点发生三相短路故障的扩展两机系统为背景,研究了风机下垂控制对系统功角首摆稳定性的影响机理。首先...随着具备频率调节功能的风电机组大规模并网,其调频控制严重影响了电力系统暂态功角的稳定性。文章以送端区域接入风机且联络线中间节点发生三相短路故障的扩展两机系统为背景,研究了风机下垂控制对系统功角首摆稳定性的影响机理。首先,基于等面积定则建立了同步机转速差值与系统暂态能量的关系,并提出了包含风机出力、并网位置和系统惯量分布等影响因素的WDPAS(Wind Turbine Droop Control Affects Power Angle Stability)指标,用于分析风机下垂控制对同步机转速差值的影响;其次,以风机最大功率点跟踪控制时的系统状态为基准,研究了故障期间及故障清除后风机附加下垂控制时,系统暂态能量的动态变化情况;最后,通过系统功角首摆最大偏移量对系统功角首摆稳定性进行评估,并在DIgSILENT/PowerFactory仿真软件中搭建了扩展两机系统仿真模型,验证了该指标的合理性及结论的正确性。展开更多
文摘A difficult but important problem in optimal control theory is the design of an optimal feedback control, i.e., the design of an optimal control as function of the phase (state) coordinates [1,2]. This problem can be solved not often. We study here the autonomous nonlinear system of second order in general form. The constraints imposed on the control input can depend on the phase (state) coordinates of the system. The goal of the control is to maximize or minimize one phase coordinate of the considered system while other takes a prescribed in advance value. In the literature, optimal control problems for the systems of second order are most frequently associated with driving both phase coordinates to a prescribed in advance state. In this statement of the problem, the optimal control feedback can be designed only for special kind of systems. In our statement of the problem, an optimal control can be designed as function of the state coordinates for more general kind of the systems. The problem of maximization or minimization of the swing amplitude is considered explicitly as an example. Simulation results are presented.
文摘Active capsule endoscopy is becoming a research hotspot in recent years. We design an active capsule robot (capsubot) with the vibrational mode. The internal force-static friction control strategy which is used in the capsubot is effective in rigid environment but not in viscoelastic environment. A particular viscoelastic material whose parameters are confirmed is set to the viscoelastic environment. We suppose that it is a periodic damped oscillation system when the capsubot make a free vibration in the environment. We propose a new control strategy whose principle is similar to a swing in the environment. The simulation results show that the new strategy is effective.
文摘针对四旋翼无人机吊挂系统的负载摆动抑制和轨迹跟踪问题,提出一种线性自抗扰控制器(Liner Active Disturbance Rejection Controller,LADRC)的轨迹跟踪控制方法。首先,考虑到四旋翼吊挂负载耦合飞行的未知外界扰动与模型的动态不确定性,为飞行器的姿态、位置设计线性自抗扰控制器,通过扩张状态观测器(Extended State Observer,ESO)观测负载摆动和环境干扰对机体的扰动,并对控制量进行相应补偿,来抑制外界和负载摆动给机体带来的干扰,保证无人机飞行过程中的稳定性。其次,针对四旋翼无人机吊挂系统在飞行过程中负载摆角过大的问题,设计加速度规划摆角抑制算法,通过摆角的实时反馈对四旋翼无人机的位置轨迹输入进行路径规划,实现飞行过程中负载摆动的抑制。最后,通过仿真结果证明该控制方法对飞行器的位置及姿态控制效果较好,同时验证了所提的轨迹规划方法能够有效抑制吊挂物的摆动,且对干扰的鲁棒性较强。
基金Supported by the National Natural Science Foundation of China(No.51375289)Shanghai Municipal National Natural Science Foundation of China(No.13ZR1415500)Innovation Fund of Shanghai Education Commission(No.13YZ020)
文摘Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by PAMs.A 3-DOF musculoskeletal bionic leg mechanism is presented,which is driven by PAMs for quadruped robots.PAM is used to simulate the compliance of biological muscle.The kinematics of the leg swing is derived,and the foot desired trajectory is planned as the sinusoidal functions.The swing experiments of the musculoskeletal leg mechanism are conducted to analyse the extension and flexion of joints.A proportional integral derivative(PID) algorithm is presented for controlling the flexion/extension of the joint.The trajectory tracking results of joints and the PAM gas pressure are obtained.Experimental results show that the developed leg mechanism exhibits good biological properties.
文摘随着具备频率调节功能的风电机组大规模并网,其调频控制严重影响了电力系统暂态功角的稳定性。文章以送端区域接入风机且联络线中间节点发生三相短路故障的扩展两机系统为背景,研究了风机下垂控制对系统功角首摆稳定性的影响机理。首先,基于等面积定则建立了同步机转速差值与系统暂态能量的关系,并提出了包含风机出力、并网位置和系统惯量分布等影响因素的WDPAS(Wind Turbine Droop Control Affects Power Angle Stability)指标,用于分析风机下垂控制对同步机转速差值的影响;其次,以风机最大功率点跟踪控制时的系统状态为基准,研究了故障期间及故障清除后风机附加下垂控制时,系统暂态能量的动态变化情况;最后,通过系统功角首摆最大偏移量对系统功角首摆稳定性进行评估,并在DIgSILENT/PowerFactory仿真软件中搭建了扩展两机系统仿真模型,验证了该指标的合理性及结论的正确性。
