Directing to the strong position coupling problem of electro-hydraulic load simulator (EHLS), this article presents an adaptive nonlinear optimal compensation control strategy based on two estimated nonlinear paramete...Directing to the strong position coupling problem of electro-hydraulic load simulator (EHLS), this article presents an adaptive nonlinear optimal compensation control strategy based on two estimated nonlinear parameters, viz. the flow gain coefficient of servo valve and total factors of flow-pressure coefficient. Taking trace error of torque control system to zero as control object, this article designs the adaptive nonlinear optimal compensation control strategy, which regards torque control output of closed-loop controller converging to zero as the control target, to optimize torque tracking performance. Electro-hydraulic load simulator is a typical case of the torque system which is strongly coupled with a hydraulic positioning system. This article firstly builds and analyzes the mathematical models of hydraulic torque and positioning system, then designs an adaptive nonlinear optimal compensation controller, proves the validity of parameters estimation, and shows the comparison data among three control structures with various typical operating conditions, including proportion-integral-derivative (PID) controller only, the velocity synchronizing controller plus P1D controller and the proposed adaptive nonlinear optimal compensation controller plus PID controller. Experimental results show that systems' nonlinear parameters are estimated exactly using the proposed method, and the trace accuracy of the torque system is greatly enhanced by adaptive nonlinear optimal compensation control, and the torque servo system capability against sudden disturbance can be greatly improved.展开更多
目的评估成年患者经外周置入中心静脉导管(peripherally inserted central catheter,PICC)的最佳长度和身高的相关性以及PICC尖端位置异常的发生率。方法回顾性分析2008-2011年200例20岁以上行PICC置管的患者,按照身高分为3组:A组150～1...目的评估成年患者经外周置入中心静脉导管(peripherally inserted central catheter,PICC)的最佳长度和身高的相关性以及PICC尖端位置异常的发生率。方法回顾性分析2008-2011年200例20岁以上行PICC置管的患者,按照身高分为3组:A组150～160cm;B组161～170cm;C组171～180cm。根据后前位X线胸片比较3组患者左右臂PICC导管的插入长度及尖端位置。结果 3组间左、右两侧PICC置管长度差异均有统计学意义(P<0.01),各组内左、右两侧的插入长度差异也有统计学意义(P<0.05)。3组患者导管最佳位置的比例差异无统计学意义(P>0.05),左右臂导管最佳位置及位点异常的比例差异无统计学意义(P>0.05),但右臂导管走行异常的发生率高于左臂(P<0.05)。结论在PICC置管时,应根据患者身高及左右侧选择适宜的置管长度,当选择右臂置管时应注意防止导管走行异位。展开更多
基金National Natural Science Foundation of China (50825502)
文摘Directing to the strong position coupling problem of electro-hydraulic load simulator (EHLS), this article presents an adaptive nonlinear optimal compensation control strategy based on two estimated nonlinear parameters, viz. the flow gain coefficient of servo valve and total factors of flow-pressure coefficient. Taking trace error of torque control system to zero as control object, this article designs the adaptive nonlinear optimal compensation control strategy, which regards torque control output of closed-loop controller converging to zero as the control target, to optimize torque tracking performance. Electro-hydraulic load simulator is a typical case of the torque system which is strongly coupled with a hydraulic positioning system. This article firstly builds and analyzes the mathematical models of hydraulic torque and positioning system, then designs an adaptive nonlinear optimal compensation controller, proves the validity of parameters estimation, and shows the comparison data among three control structures with various typical operating conditions, including proportion-integral-derivative (PID) controller only, the velocity synchronizing controller plus P1D controller and the proposed adaptive nonlinear optimal compensation controller plus PID controller. Experimental results show that systems' nonlinear parameters are estimated exactly using the proposed method, and the trace accuracy of the torque system is greatly enhanced by adaptive nonlinear optimal compensation control, and the torque servo system capability against sudden disturbance can be greatly improved.
文摘目的评估成年患者经外周置入中心静脉导管(peripherally inserted central catheter,PICC)的最佳长度和身高的相关性以及PICC尖端位置异常的发生率。方法回顾性分析2008-2011年200例20岁以上行PICC置管的患者,按照身高分为3组:A组150～160cm;B组161～170cm;C组171～180cm。根据后前位X线胸片比较3组患者左右臂PICC导管的插入长度及尖端位置。结果 3组间左、右两侧PICC置管长度差异均有统计学意义(P<0.01),各组内左、右两侧的插入长度差异也有统计学意义(P<0.05)。3组患者导管最佳位置的比例差异无统计学意义(P>0.05),左右臂导管最佳位置及位点异常的比例差异无统计学意义(P>0.05),但右臂导管走行异常的发生率高于左臂(P<0.05)。结论在PICC置管时,应根据患者身高及左右侧选择适宜的置管长度,当选择右臂置管时应注意防止导管走行异位。
