US 12,305,673 B1
Methods for fault diagnosis of pressure sensor of electro-hydraulic system with explicit controller and implicit controller in parallel
Gang Li, Nanchang (CN); Diancheng Chen, Nanchang (CN); Ruqi Ding, Nanchang (CN); Min Cheng, Chongqing (CN); Liqiu Liao, Nanchang (CN); Zhanchao He, Nanchang (CN); Guoliang Hu, Nanchang (CN); Qianjie Liu, Nanchang (CN); and Liping Zeng, Nanchang (CN)
Assigned to EAST CHINA JIAOTONG UNIVERSITY, Nanchang (CN); and CHONGQING UNIVERSITY, Chongqing (CN)
Filed by EAST CHINA JIAOTONG UNIVERSITY, Jiangxi (CN); and CHONGQING UNIVERSITY, Chongqing (CN)
Filed on Oct. 12, 2024, as Appl. No. 18/914,117.
Claims priority of application No. 202311469581.9 (CN), filed on Nov. 7, 2023.
Int. Cl. F15B 19/00 (2006.01); F15B 13/08 (2006.01)
CPC F15B 19/005 (2013.01) [F15B 13/086 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method for fault diagnosis of a pressure sensor of an electro-hydraulic system with an explicit controller and an implicit controller in parallel implemented by a processor, comprising:
receiving parameter information of the electro-hydraulic system, the parameter information including a first chamber pressure of a hydraulic actuator and a second chamber pressure of the hydraulic actuator;
obtaining, based on the first chamber pressure, an opening signal of an independent metering valve 1 controlled by the explicit controller; and obtaining, based on an online estimate value of the first chamber pressure, an opening signal of the independent metering valve 1 controlled by the implicit controller;
obtaining, based on the second chamber pressure, an opening signal of an independent metering valve 2 controlled by the explicit controller using a pressure control loop; and obtaining, based on a reference velocity of the hydraulic actuator, an opening signal of the independent metering valve 2 controlled by the implicit controller using a flow control loop;
determining a first residual of the independent metering valve 1 by performing subtraction on the opening signal of the independent metering valve 1 calculated by both the implicit controller and the explicit controller at the same time. and determining a second residual of the independent metering valve 2 by performing subtraction on the opening signal of the independent metering valve 2 calculated by both the implicit controller and the explicit controller at the same time;
identifying whether the independent metering valve 1 and the independent metering valve 2 are faulty by comparing the first residual and the second residual respectively with preset thresholds corresponding to the first residual and the second residual, wherein
the obtaining an online estimate value of the first chamber pressure by estimating in the initial state, based on the pressure of two chambers of a hydraulic actuator which different weights are assigned, the first chamber pressure includes:
designing a tracking controller GTr of the first chamber pressure:

OG Complex Work Unit Math
where s denotes a transfer function after a Laplace transform of a first differential link, Kp denotes a proportional adjustment coefficient, Ki denotes an integral adjustment coefficient, and ωn and ξ denote a closed-loop intrinsic frequency and damping of the tracking controller; and
determining the online estimate value according to a following equation:

OG Complex Work Unit Math
wherein

OG Complex Work Unit Math
denotes the online estimate value, p1 denotes the first chamber pressure, p2 denotes the second chamber pressure, p2,ref denotes a preset target reference pressure, and GPI denotes a proportional integral controller,

OG Complex Work Unit Math
as a weight coefficient responding directly to changes in p1, and

OG Complex Work Unit Math
as a weight coefficient responding directly to changes in (p2,ref−p2);
the obtaining, based on the first chamber pressure, an opening signal of an independent metering valve 1 controlled by the explicit controller includes:
adopting the flow control loop for the independent metering valve 1 controlled by the explicit controller and determining the opening signal of the independent metering valve 1 controlled by the explicit controller according to a following equation:
u1=u−1(vref·A1,ps−p1),
where u1 denotes the opening signal, vref denotes the reference velocity of the hydraulic actuator, A1 denotes an area of a rodless chamber of the hydraulic actuator, ps denotes a pressure of the electro-hydraulic system, p1 denotes the first chamber pressure, u−1 (qref,Δp1) denotes a valve opening calibrated in advance using a reference flow and a differential pressure, qref denotes a product of the reference velocity vref and the area A1 of the rodless chamber, and Δp1 denotes a difference between the pressure ps of the electro-hydraulic system and the first chamber pressure p1;
the obtaining, based on the online estimate value of the first chamber pressure, an opening signal of the independent metering valve 1 controlled by the implicit controller includes:
adopting the flow control loop for the independent metering valve 1 controlled by the implicit controller and determining the opening signal u1′ of the independent metering valve 1 controlled by the implicit controller according to a following equation:
u1′=u−1(vref·A1,ps−p1),
where p1 denotes the online estimate value of the first chamber pressure, u−1 (qref,Δp1′) denotes a valve opening calibrated in advance using a reference flow and a differential pressure, and Δp1′ denotes a difference between the pressure ps of the electro-hydraulic system and the online estimate value p1;
the obtaining, based on the second chamber pressure, an opening signal of an independent metering valve 2 controlled by the explicit controller using a pressure control loop includes:
adopting the pressure control loop for the independent metering valve 2 controlled by the explicit controller and determining the opening signal of the independent metering valve 2 controlled by the explicit controller according to a following equation:

OG Complex Work Unit Math
where u2 denotes the opening signal, p2 denotes the second chamber pressure, p2,ref denotes the preset target reference pressure, t denotes an integration starting time, and ti denotes an integration termination time; and
the obtaining, based on a reference velocity of the hydraulic actuator, an opening signal of the independent metering valve 2 controlled by the implicit controller using a flow control loop includes:
adopting the flow control loop for the independent metering valve 2 controlled by the implicit controller and determining the opening signal u2′ of the independent metering valve 2 controlled by the implicit controller according to a following equation:
u2′=u−1(vref·A2,p2−pr),
where A2 denotes an area of a rod chamber of the hydraulic actuator, pr denotes a return oil pressure, u−1 (qref′,Δp2) denotes a valve opening calibrated in advance using a reference flow and a differential pressure, qref′ denotes a product of the reference velocity vref and the area A2 of the rod chamber, and Δp2 denotes a difference between the second chamber pressure p2 and the return oil pressure pr;
determining a flow adjustment amount based on a relationship between the first residual and the preset threshold corresponding to the first residual and a relationship between the second residual and the preset threshold corresponding to the second residual, including:
in response to a determination that the first residual exceeds the preset threshold corresponding to the first residual and the second residual exceeds the preset threshold corresponding to the second residual,
updating, based on a second preset rule, the flow adjustment amount,
generating, based on an updated flow adjustment amount, at least one of a power source adjustment instruction and an opening adjustment instruction; and
adjusting, based on the power source adjustment instruction, a power source flow by adjusting a working volume of a piston within a power source;
adjusting, based on the opening adjustment instruction, a degree of valve spool opening, by the explicit controller.