If the rigidity of a mechanism is stiff enough, the position synchronous error of the two cylinders driving one degree-of-freedom （DOF） of the mechanism may be less than the resolution of position sensors. To handle...If the rigidity of a mechanism is stiff enough, the position synchronous error of the two cylinders driving one degree-of-freedom （DOF） of the mechanism may be less than the resolution of position sensors. To handle this synchronization problem this paper proposes a force/position switching scheme, which partitions the two cylinders into a master cylinder and a slave cylinder. The master cylinder is always position tracking controlled by a second-order sliding mode controller and the slave cylinder is integrated with a force tracking controller which is a first order sliding mode controller. When the position tracking error is less than a given value, the slave cylinder switches to be force controlled. Two synchronization control methods are presented based on the switching scheme： the master - master ＋ force/position switching control and the master - slave ＋ force/position switching control. Simulations show that the formance compared with two given proposed synchronization control position-based control methods. methods can get a better per-展开更多
In this paper, taking two degrees of freedom on the armature–flapper assembly into account, a seventh-order model is deduced and proposed for the dynamic response of a two-stage electro-hydraulic servo valve from non...In this paper, taking two degrees of freedom on the armature–flapper assembly into account, a seventh-order model is deduced and proposed for the dynamic response of a two-stage electro-hydraulic servo valve from nonlinear equations. These deductions are based on fundamental laws of electromagnetism, fluid, and general mechanics. The coefficients of the proposed seventhorder model are derived in terms of servo valve physical parameters and fluid properties explicitly.For validating the results of the proposed model, an AMESim simulation model based on physical laws and the existing low-order models validated by other researchers through experiments are used to compare with the seventh-order model. The results show that the seventh-order model can reflect the physical behavior of the servo valve more explicitly than the existing low-order models and it could provide guidance more easily for a linear control design approach and sensitivity analysis than the AMESim simulation model.展开更多
基金Supported by the Major State Basic Research Development Program of China(No.2006CB5406)Important National Science&Technology Specific Projects(No.2009ZX04002-061,2009ZX04004-102)
文摘If the rigidity of a mechanism is stiff enough, the position synchronous error of the two cylinders driving one degree-of-freedom （DOF） of the mechanism may be less than the resolution of position sensors. To handle this synchronization problem this paper proposes a force/position switching scheme, which partitions the two cylinders into a master cylinder and a slave cylinder. The master cylinder is always position tracking controlled by a second-order sliding mode controller and the slave cylinder is integrated with a force tracking controller which is a first order sliding mode controller. When the position tracking error is less than a given value, the slave cylinder switches to be force controlled. Two synchronization control methods are presented based on the switching scheme： the master - master ＋ force/position switching control and the master - slave ＋ force/position switching control. Simulations show that the formance compared with two given proposed synchronization control position-based control methods. methods can get a better per-
基金the National Natural Science Foundation of China (No. 50975055) for financial support
文摘In this paper, taking two degrees of freedom on the armature–flapper assembly into account, a seventh-order model is deduced and proposed for the dynamic response of a two-stage electro-hydraulic servo valve from nonlinear equations. These deductions are based on fundamental laws of electromagnetism, fluid, and general mechanics. The coefficients of the proposed seventhorder model are derived in terms of servo valve physical parameters and fluid properties explicitly.For validating the results of the proposed model, an AMESim simulation model based on physical laws and the existing low-order models validated by other researchers through experiments are used to compare with the seventh-order model. The results show that the seventh-order model can reflect the physical behavior of the servo valve more explicitly than the existing low-order models and it could provide guidance more easily for a linear control design approach and sensitivity analysis than the AMESim simulation model.
