Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F30/00—Computer-aided design [CAD]
  • G06F30/10—Geometric CAD
  • G06F30/17—Mechanical parametric or variational design
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F2111/00—Details relating to CAD techniques
  • G06F2111/06—Multi-objective optimisation, e.g. Pareto optimisation using simulated annealing [SA], ant colony algorithms or genetic algorithms [GA]

Definitions

• the present invention relates to a method and a device for determining a model of a technical system with the features according to the claims.
• Manipulated variable combinations are displayed in the form of a convex hull. Based on this now known variation space can then be made an adaptation of the experimental design used.
• Boundary points is again formed a convex hull. Starting from this convex hull, as described in a next step, a new determination of boundary points takes place, so that the convex hull, which in each step corresponds only to the respectively determined variation space, approaches the actual space of variation.
• the methods described rely on extensive upstream measurements of the
• Variationspacees advance. As a result of this upstream and extensive process step of stepwise measurement of the variation space, valuable time is needed. A further disadvantage is also that the quality of the resulting parameters of the model to be determined is reduced, since the position of the experimental points is optimized for the experimental space finding.
• This object is achieved in particular by means of a method for determining a model of a technical system, wherein by means of the model based on
• Input variables / input value combinations output variables of the technical system can be determined, with the following steps:
• Input variables / input variable combinations and measurement of output variables on the technical system wherein at least one input variable / input variable combination is determined which causes an output variable which lies on an output limit
• Input variables / input quantity combinations Limit points of the first convex hull are, whereby hyperplanes lie at the boundary points, wherein the hyperplanes include the set of the determined input variables / input value combinations,
• Input variables / input quantity combinations are within the input size limits, as well as within the first convex hull and / or outside the first convex hull, excluding input variables / input quantity combinations lying within at least one further convex hull, wherein each further convex hull is merely a boundary point of the first convex hull Shell and the intersections of the present at only one boundary point hyperplanes with the input size limits and optionally existing intersections of the input quantity limits are the boundary points of at least one other convex hull, where which corresponds to only one limit point of an input quantity / input quantity combination which causes an output quantity which lies on an output quantity limit,
• the determination of a test space / a convex casing takes place on the basis of previously performed measurements in individual steps or at any time.
• this convex hull is widened by the described strategy in such a way that a new convex region arises in which the planning of a test point takes place.
• test point is again the convex hull of all previously made measurements, this is extended with the described strategy, a new point planned and so on. Compared to the prior art, only a minimal initial design plan is measured, in any case eliminates the costly determination of system boundaries in an upstream process step.
• the convex hull is iteratively extended in an online process, so that points outside the convex hull are also planned.
• a new convex hull is calculated and expanded again.
• the end result of the expansion of the convex hull according to the invention is a non-measured region, but this indicates the maximum possible variation space at this time, provided that a convex variation space is assumed.
• the release of a further area which is to be used for the experimental design.
• the combination of determining the maximum possible convex envelope size (extension strategy) and the experimental design within this space on the basis of other criteria results in a synergy effect according to the invention. Ie. the coupling between finding the boundaries of the variation space and selecting suitable experimental points for modeling is resolved.
• the technical system has inputs and outputs.
• the technical system can be any engine, for example one
• Heat engine or an electric machine may be an internal combustion engine.
• the internal combustion engine can according to the Ottofact or the
• the internal combustion engine has a variable
• the internal combustion engine has both an adjustable
• Input variable combination of the technical system which is here an internal combustion engine, namely the (variable) timing of the intake valves and (variable) timing of the
• Residual gas in a combustion chamber of the engine influenced or changed or so results in a new input variable combination.
• the residual gas content may be a first output.
• input variable combination denotes a combination of two or more input variables
• the proportion of residual gas increases as a function of the separation of the intake and exhaust valves, ie the later the exhaust valves close and the earlier the intake valves open, the greater the overlap and thus the residual gas content.
• a further output variable can be considered, namely the smoothness of the internal combustion engine or the extent of the so-called cyclic fluctuations or the standard deviation of the indicated mean pressure of the internal combustion engine.
• the aim in the calibration or application of an internal combustion engine it is known to find optimum settings, in this case, the overlap and thus adjust the residual gas content so that the residual gas content is as high as possible and consequently z.
• the fuel consumption is as low as possible (fuel consumption may be a further output variable) and / or the internal combustion engine as low as possible releases nitrogen oxides (the nitrogen oxide concentration in the exhaust gas may be yet another output variable) and / or the internal combustion engine is not unacceptably many hydrocarbons (the hydrocarbon concentration in the exhaust gas can be yet another output variable),
• the smoothness of the internal combustion engine may not be deteriorated so that a predetermined limit is violated.
• a limit value GW relating to the smooth running of the internal combustion engine, which must not be violated, see FIG. 1.
• This profile of a limit value GW is initially unknown. The aim is to determine a model with which it is possible, based on input variables, here on the basis of the variable timing of the
• Input size space / input size range to optimize or align accordingly.
• variable timing of the intake valves - is determined by a latest possible intake valve timing or latest possible opening of the intake valves (left vertical line in FIG 1) is limited and by an earliest possible timing of the intake valves or an earliest possible opening the
• Inlet valves (right vertical line in Figure 1) is limited.
• Two input size limits further result from the fact that the range of adjustability of the second input variable - here the variable timing of the exhaust valves - by an earliest possible timing of the exhaust valves or the earliest possible closing of the exhaust valves (lower horizontal line in Figure 1) is limited and by a latest possible control time of the exhaust valves or a latest possible closing of the exhaust valves (upper horizontal line in Figure 1) is limited.
• output limits are specified, ie in particular minimum and / or maximum values which may not be exceeded or fallen short of as a result of a setting / variation of the input variables. These may be so-called hard or soft limits, see above in the cited prior art. Following the described embodiment, there is a
• Output limit in particular in that due to the variation of the timing of the intake and exhaust valves of the limit GW regarding the smoothness must not be violated. Also conceivable here again (alternatively or additionally) is the specification of the limits GW (as output variable limits) with regard to the fuel consumption and / or the nitrogen oxide. Hydrocarbon concentration in the exhaust gas.
• a determination of input variables takes place within the previously specified input quantity limits, that is to say a determination of the valve timing
• Input variables / input variable combinations are preferably carried out by means of a
• Input quantity limits namely four combinations of timing of the intake valves and timing of the exhaust valves, highlighted in Figure 1 by circular rings. In other words, four different overlaps are given.
• the determination of these input variables within the input quantity limits as well as the output variables caused thereby or caused by the technical system takes place by setting these four combinations of intake valve timing and exhaust valve timing on the internal combustion engine (especially in conjunction with FIG a suitable test equipment / test bench and known measurement technology) and by measuring the output variables.
• the smoothness, the fuel consumption or the concentration of nitrogen oxides / hydrocarbons in the exhaust gas can be such an output variable.
• At least one input quantity / input quantity combination is determined which causes an output quantity which lies on a (previously defined) output size limit.
• a (previously defined) output size limit As described, only smoothness can be a possible starting point in this respect is looked at.
• G1, G3 two input variables or two combinations of intake valve timing and timing of the exhaust valves are determined (G1, G3), each causing an output that the smoothness corresponds to the limit GW, ie the respective output is on an output quantity limit or on the course of the limit value GW shown in FIG.
• Input size limits and the determination of the associated outputs by setting inputs and measuring outputs on the technical system not only / not exclusively that the determination of at least one input that causes an output that is on an output limit, directly by setting
• Input variables and measurement of output quantities takes place on the technical system, ie that the technical system or the internal combustion engine actually has to be brought to a limit range in order to determine the input variable which causes an output variable which lies on an output limit. Rather, this determination can also be made indirectly. This can be done according to the invention, that although an adjustment of input variables and measurement of output variables on the technical system / the internal combustion engine takes place, but not immediately at least one output variable is sought / measured on a
• Input variables / input variable combinations the determination of a variation space and that the determination of a first convex hull.
• a convex set - here the set of detected inputs - by hyperplanes that lie on the edge of the convex set. Ie. some or all of the identified
• Input variables / input variable combinations can be boundary points of a convex hull.
• a convex hull is known to be the smallest convex polygon covering the set of all points (here, input sizes / input size combinations).
• Input variables / input variable combinations determined, then all are determined Input variables / input quantity combinations Limit points of the first convex hull. To limit the convex amount of four shown in FIG.
• Input variables / input quantity combinations are used hyperplanes, d. H.
• four hyperplanes lie on the four boundary points (G1 - G4) of the convex set.
• the first hyperplane H1 abuts the boundary point G1 and the boundary point G2.
• the second hyperplane H2 is located at the boundary point G1 and at the boundary point G3.
• Limit points of the first convex hull are, to which hyperplanes abut, so that the
• Hyperplanes include the convex set of detected inputs.
• an extension of the first convex hull takes place by input variables which lie outside the currently present first convex hull. Ie. it is explicitly determined outside the first convex hull of the set of input variables previously determined as described above, other input variables. For this purpose, a setting of other input variables and measurement of
• the envelope which is likewise convex here, it can also be a concave envelope
• the boundary point G1 the boundary point G2 and the intersection S2 (FIG. which results from the input size limit and the second hyperplane H2 intersecting)
• Input size limit (here the right vertical line, which represents the maximum advance of the intake camshaft) by the hyperplanes H1 and H2 and the other
• Input size limit is included. Another boundary point of this likewise convex hull is the intersection point E1 of the input size limits with each other. Input variables can also be determined in the space / region or within the convex hull whose boundary points are the intersection E2 of the input quantity limits, the boundary point G2 and the boundary point G4.
• Input variables can also be determined in the space / region or within the convex hull whose / their boundary points the intersection E3 of the input size limits, the boundary point G4, the intersection S3 (resulting from the fact that the input size limit and the second hyperplane H2 cut) and are the boundary point G3.
• Input variables can also be determined in the space / region or within the convex hull whose boundary points the intersection point S4 (which results from the fact that the input size boundary and a hyperplane intersect), the intersection S1 (which results from that the input size limit and the first hyperplane H1 intersect), the
• the two areas / spaces / convex hulls not hatched in FIG. 1 whose boundary points S1, S2 and G1 as well as S3, S4 and G3 are excluded from the further determination of input quantities and measurement of output quantities on the technical system, although these further Input variables are within the input quantity limits or outside the first convex hull (which is bounded by the boundary points G1-G4), as in the previously described cases.
• Input size / input size combination that causes an output that is on an output size limit.
• the two boundary points G1 and G3 according to FIG. 1 are not part of the one convex hull, which includes input variables to be excluded in the further course, but exclusively only the boundary point G1.
• Another boundary point of the one convex hull (in FIG.
• the second convex hull (in FIG. 1 on the left, not hatched), which comprises input variables to be excluded (in the further step of the method), is also formed.
• these further convex hulls continue to have boundary points that are intersections of input size limits with each other.
• the point of intersection S1 moves to the left, ie to the left of the point of intersection E4 of the input quantity limits, so that the above-described convex envelope having the input variables to be excluded not only three but also includes four boundary points, namely in addition to the intersection E4 of the input quantity boundaries with each other.
• input variables and associated output variables were determined, wherein the input quantities are part / elements of the quantity which according to the invention has been expanded within the input size limits, that is to say with the exclusion of defined input variables a training of the parameters of the model of the technical system is carried out on the basis of these (determined) input variables and output variables, as is generally known.
• the inventive method for determining a model of a technical system is performed stepwise, d. H. the first convex hull is iteratively extended.
• At least one input variable / input variable combination is again determined which causes an output variable which lies on an output limit.
• the determination of an expanded convex hull is then performed on the basis of the now determined input variables / input quantity combinations, again some or all now determined input quantities / input quantity combinations being boundary points of the extended convex hull and in turn abutting the boundary points hyperplanes and the hyperplanes the set the now determined
• Input size limits lie, as well as within the extended convex hull and / or outside the widened convex hull, to the exclusion of
• Input variables / input quantity combinations which lie within at least one further convex hull, wherein each further convex hull is merely a boundary point of the extended convex hull and the intersections of the hyperplanes adjoining this only one boundary point with the input size limits and optionally existing intersection points of the
• Input size limits are boundary points of the at least one further convex hull, wherein the only one boundary point of the extended convex hull corresponds to an input quantity / input quantity combination determined in the previous step, which causes an output quantity which lies on an output size limit.
• a device for determining a model of a technical system is furthermore provided. This is characterized in that a computer designed for carrying out the method according to the invention has a CPU and a
• the computer with a CPU is a computer that is part of a well known one
• Test bench automation is or is associated with it. This test stand automation or the automation system is in turn connected to the considered technical system.
• the test bed automation is also designed so that not only the setting of
• test bench automation can thus be a

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• Theoretical Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Pure & Applied Mathematics (AREA)
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• General Engineering & Computer Science (AREA)
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• Combined Controls Of Internal Combustion Engines (AREA)
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• 2016
  • 2016-04-15 DE DE102016106976.0A patent/DE102016106976B4/de active Active
• 2017
  • 2017-04-11 WO PCT/DE2017/100294 patent/WO2017178015A1/de active Application Filing
  • 2017-04-11 JP JP2018554002A patent/JP6873154B2/ja active Active

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