Method for determining control model parameters of a control model of an axial piston pump

Patent metadata

Field	Value
Publication number	US-12510069-B2
Application number	US-202218294448-A
Country	US
Kind code	B2
Filing date	Aug 8, 2022
Priority date	Aug 12, 2021
Publication date	Dec 30, 2025
Grant date	Dec 30, 2025

Abstract

A method is for ascertaining control model parameters of a control model of an axial piston pump. The method models at least one control variable of an adjustment unit of the axial piston pump as a function of operating variables. Operating points of the axial piston pump each are characterized by operating values of the operating variables. The method includes (i) providing initial control model parameters of the control model and an operating state set including a plurality of initial first operating points, (ii) providing initial safety model parameters of a safety model based on a safety set including a plurality of initial second operating points and associated safety values, and (iii) determining a further operating point which is not yet included in the operating state set. The further operating point is determined such that a variance of the control model is maximized.

First claim

The invention claimed is:

1 . A method for ascertaining control model parameters of a control model of an axial piston pump, the axial piston pump including a swash plate having an adjustable swivel angle for adjusting a pump delivery volume of the axial piston pump, wherein an adjustment unit of the axial piston pump imparts an adjusting force on the swash plate for adjusting the swivel angle, wherein the adjusting force is dependent on an actuating pressure in at least one actuating chamber of the axial piston pump, wherein the control model is configured to model at least one control variable of the adjustment unit as a function of operating variables, wherein operating points of the axial piston pump are characterized in each case by specific operating values of the operating variables, the method comprising:
providing initial control model parameters of the control model; providing an operating state set comprising a plurality of initial first operating points of the axial piston pump; providing initial safety model parameters of a safety model, the initial safety model parameters based on a safety set comprising a plurality of initial second operating points of the axial piston pump and a corresponding safety value for each of the initial second operating points, wherein the safety model is configured to model a safety variable as a function of the operating variables, wherein the safety variable indicates whether fault-free operation is possible or not possible at a respective operating point of the initial second operating points; executing the following steps once or several times:
determining a further operating point of the axial piston pump which is not yet included in the operating state set, wherein the further operating point is determined by:
maximizing a variance of the control model under a condition that a probability obtained by the safety model that the fault-free operation is not possible at the further operating point is less than or equal to a specified safety threshold;
updating the operating state set and the control model parameters of the control model based on the further operating point; and
updating the safety set and the safety model parameters of the safety model, based on the further operating point; and

operating the axial piston pump to deliver hydraulic fluid according to the updated operating state set, including the further operating point, so that the axial piston pump is configured for the fault-free operation.

2 . The method according to claim 1 , wherein the updating of the operating state set and the control model parameters comprises:
ascertaining or measuring a further at least one control variable of the adjustment unit so that the further operating point is reached by the axial piston pump; adding the further operating point and the ascertained or measured further at least one control variable to the operating state set to form a supplemented operating state set; and re-determining the control model parameters of the control model based on the supplemented operating state set.

3 . The method according to claim 2 , wherein updating the safety set and the safety model parameters of the safety model comprises:
determining a corresponding safety value for the further operating point; adding the further operating point and the determined corresponding safety value to the safety set to form a supplemented safety set; and re-determining the safety model parameters of the safety model based on the supplemented safety set.

4 . The method according to claim 1 , wherein the providing of the operating state set comprises:
determining the initial first operating points using a physical modeling of the axial piston pump, wherein in the physical modeling the initial first operating points are determined in such a way that the fault-free operation is possible; or providing the initial first operating points using standard operating points of the axial piston pump from which it is known in advance that the fault-free operation is possible.

5 . The method according to claim 4 , wherein the providing of the operating state set further comprises:
determining the operating values associated with the initial first operating points using the physical modeling of the axial piston pump or by operating the axial piston pump and adjusting the at least one control variables so that each respective initial first operating point is reached; and determining the control model parameters based on the determined initial first operating points and the determined associated operating values.

6 . The method according to claim 1 , wherein:
when providing the initial safety model parameters of the safety model, the initial second operating points comprise both safe operating points at which the fault-free operation is possible and unsafe operating points at which the fault-free operation is not possible, and the safe operating points at least partially comprise the initial first operating points.

7 . The method according to claim 1 , wherein a number of the initial first operating points and a number of the initial second operating points lie independently of one another in a range from 10 to 100 operating points.

8 . The method according to claim 1 , wherein the specified safety threshold is less than or equal to 5%.

9 . The method according to claim 1 , wherein:
the determining of the further operating point, the updating of the operating state set and the control model parameters, and the updating of the safety set and the safety model parameters are executed several times until an abort condition is fulfilled, and the abort condition comprises one or more of:
the variance of the control model being below a first predetermined threshold,
a change in the control model parameters when updating the control model parameters being below a second predetermined threshold,
a change in the safety model parameters when updating the safety model parameters being below a third predetermined threshold, and
a distance of the further operating point from a set of other operating points in the operating state set being below a fourth predetermined threshold.

10 . The method according to claim 1 , wherein the operating variables comprise one or more of a working pressure of the axial piston pump, a rotational speed of the axial piston pump, and the swivel angle of the swash plate.

11 . The method according to claim 1 , wherein the at least one control variable comprises at least one control current for at least one pressure control valve of the adjustment unit which is electromagnetically actuable.

12 . The method according to claim 1 , wherein:
the control model and/or the safety model are regression models, the operating variables are independent variables and the at least one control variable is at least one dependent variable, and wherein Gaussian process models are used as the regression models.

13 . A processor configured to execute a method according to claim 1 .

14 . A computer program that causes a processor to perform a method according to claim 1 when executed on the processor.

15 . A non-transitory machine-readable storage medium on which the computer program according to claim 14 is stored.

16 . The method according to claim 1 , wherein the specified safety threshold is 2%.

17 . The method according to claim 1 , wherein the specified safety threshold is 1%.

18 . The method according to claim 1 , wherein the specified safety threshold is 0.5%.

19 .

Assignees

• Bosch Gmbh Robert

Inventors

• Zimmer Christoph
• Trachte Adrian

Classifications

• F04B49/002

  Hydraulic systems to change the pump delivery · CPC title

• F04B49/10

  Other safety measures · CPC title

• F04B49/065 Primary

  and making use of computers · CPC title

• F04B1/324

  by changing the inclination of the swash plate · CPC title

• F04B1/295

  by changing the inclination of the swash plate · CPC title