Since the joint actuator of the space robot executes the control instructions frequently in the harsh space environment,it is prone to the partial loss of control effectiveness(PLCE)fault.An adaptive fault-tolerant co...Since the joint actuator of the space robot executes the control instructions frequently in the harsh space environment,it is prone to the partial loss of control effectiveness(PLCE)fault.An adaptive fault-tolerant control algorithm is designed for a space robot system with the uncertain parameters and the PLCE actuator faults.The mathematical model of the system is established based on the Lagrange method,and the PLCE actuator fault is described as an effectiveness factor.The lower bound of the effectiveness factors and the upper bound of the uncertain parameters are estimated by an adaptive strategy,and the estimated value is fed back to the control algorithm.Compared with the traditional fault-tolerant algorithms,the proposed algorithm does not need to predetermine the lower bound of the effectiveness factor,hence it is more in line with the actual engineering application.It is proved that the algorithm can guarantee the stability of the closed-loop system based on the Lyapunov function method.The numerical simulation results show that the proposed algorithm can not only compensate for the uncertain parameters,but also can tolerate the PLCE actuator faults effectively,which verifies the effectiveness and superiority of the control scheme.展开更多
本文基于地面测量布格异常和EIGEN-6C4(European Improved Gravity model of the Earth by New techniques version 6C4)重力资料,以USTClitho2.0(Unified Seismic Tomography models for continental China lithosphere version 2.0)...本文基于地面测量布格异常和EIGEN-6C4(European Improved Gravity model of the Earth by New techniques version 6C4)重力资料,以USTClitho2.0(Unified Seismic Tomography models for continental China lithosphere version 2.0)岩石圈结构模型为约束,利用顾及地壳密度横向变化的布格改正、小波多尺度分解、均衡改正、Moho面重力反演和岩石圈有效弹性厚度(T_(e))反演等方法,计算了郯庐断裂带中南段布格异常及其多尺度分解结果、深部均衡异常、Moho面深度、岩石圈有效弹性厚度及荷载比,结合地震活动性和地球物理资料,综合分析了该地区重力异常构造背景及其与地震活动性的关系.结果表明,沿郯庐断裂带的重力异常在嘉山以南段、嘉山-新沂段和新沂-安丘段呈显著差异性3段式分布,且与地震活动性分段特征高度统一.地震活动性强的嘉山以南段和新沂-安丘段具有浅部布格异常线性条带、深部布格异常高梯度带、Moho面陡变带或上隆带、地壳重力不均衡、低岩石圈有效弹性厚度和高荷载比特征,表明其深部结构破坏程度高,岩石圈力学强度低,且存在均衡调整作用,有利于应力及时释放,因而地震活动频繁;地震活动性弱的嘉山-新沂段浅部布格异常散乱,深部布格异常高值区和低值正均衡异常区穿过郯庐断裂带,Moho面变化平缓,岩石圈有效弹性厚度值高,荷载比低,对应扬子地块俯冲于华北断块区之下的遗留深部构造,其深部结构破坏程度较低,岩石圈力学强度大,且均衡调整作用不强,岩石圈不易发生破裂,因而地震频率很低.郯城8.5级地震位于横穿郯庐断裂带的深部构造北缘附近,是最易于积累应力的部位,深部构造和岩石圈有效弹性厚度剧烈变化导致应力分布不均匀以及较强的均衡调整作用可能是地震的触发因素.嘉山-新沂段具备有利于应力长期积累的深部构造条件,应持续关注其应力积累状态和强震风险.展开更多
基金supported by the National Natural Science Foundation of China(11372073,11072061)
文摘Since the joint actuator of the space robot executes the control instructions frequently in the harsh space environment,it is prone to the partial loss of control effectiveness(PLCE)fault.An adaptive fault-tolerant control algorithm is designed for a space robot system with the uncertain parameters and the PLCE actuator faults.The mathematical model of the system is established based on the Lagrange method,and the PLCE actuator fault is described as an effectiveness factor.The lower bound of the effectiveness factors and the upper bound of the uncertain parameters are estimated by an adaptive strategy,and the estimated value is fed back to the control algorithm.Compared with the traditional fault-tolerant algorithms,the proposed algorithm does not need to predetermine the lower bound of the effectiveness factor,hence it is more in line with the actual engineering application.It is proved that the algorithm can guarantee the stability of the closed-loop system based on the Lyapunov function method.The numerical simulation results show that the proposed algorithm can not only compensate for the uncertain parameters,but also can tolerate the PLCE actuator faults effectively,which verifies the effectiveness and superiority of the control scheme.
文摘本文基于地面测量布格异常和EIGEN-6C4(European Improved Gravity model of the Earth by New techniques version 6C4)重力资料,以USTClitho2.0(Unified Seismic Tomography models for continental China lithosphere version 2.0)岩石圈结构模型为约束,利用顾及地壳密度横向变化的布格改正、小波多尺度分解、均衡改正、Moho面重力反演和岩石圈有效弹性厚度(T_(e))反演等方法,计算了郯庐断裂带中南段布格异常及其多尺度分解结果、深部均衡异常、Moho面深度、岩石圈有效弹性厚度及荷载比,结合地震活动性和地球物理资料,综合分析了该地区重力异常构造背景及其与地震活动性的关系.结果表明,沿郯庐断裂带的重力异常在嘉山以南段、嘉山-新沂段和新沂-安丘段呈显著差异性3段式分布,且与地震活动性分段特征高度统一.地震活动性强的嘉山以南段和新沂-安丘段具有浅部布格异常线性条带、深部布格异常高梯度带、Moho面陡变带或上隆带、地壳重力不均衡、低岩石圈有效弹性厚度和高荷载比特征,表明其深部结构破坏程度高,岩石圈力学强度低,且存在均衡调整作用,有利于应力及时释放,因而地震活动频繁;地震活动性弱的嘉山-新沂段浅部布格异常散乱,深部布格异常高值区和低值正均衡异常区穿过郯庐断裂带,Moho面变化平缓,岩石圈有效弹性厚度值高,荷载比低,对应扬子地块俯冲于华北断块区之下的遗留深部构造,其深部结构破坏程度较低,岩石圈力学强度大,且均衡调整作用不强,岩石圈不易发生破裂,因而地震频率很低.郯城8.5级地震位于横穿郯庐断裂带的深部构造北缘附近,是最易于积累应力的部位,深部构造和岩石圈有效弹性厚度剧烈变化导致应力分布不均匀以及较强的均衡调整作用可能是地震的触发因素.嘉山-新沂段具备有利于应力长期积累的深部构造条件,应持续关注其应力积累状态和强震风险.
