DE102019100584A1 - Method for determining a prosthetic foot model, computer readable storage medium and system - Google Patents

Abstract

Prosthetic feet are not automatically adaptable to the individual needs of individual patients. The invention therefore relates to methods for determining a prosthetic foot model (60) which indicates a prosthetic foot (85), comprising the following steps: a) Parameterizing a prosthetic foot model (10) which is a prosthetic foot indicates with at least one input parameter (61); b) calculating (64) at least one load case of the parameterized prosthetic foot model (63) to generate load case result data (31, 32); c) adjusting (70) at least one free parameter value (17, 19 , 20) of the parameterized prosthetic foot model (10) taking into account the load case result data (31, 32); d) determining an optimized prosthetic foot model (71) using the at least one adapted free parameter value (17, 19, 20).

Description

The invention relates to a method for determining a prosthetic foot model, a computer-readable storage medium and a system.

A prosthetic foot is out of the DE 20 2015 007 994 known. Prosthetic feet are exposed to extremely high loads. Previous prosthetic feet are therefore manufactured from plastics, fiber-reinforced materials and / or from metal alloys by injection molding or laminating. From the DE 10 2014 006 727 B3 prosthesis feet are known which are produced by means of additive manufacturing processes, for example 3D printing.

Several aspects are important for fulfilling the functional requirements of the prosthetic foot. The cushioning properties, which are most evident when heel strikes, are important for comfort when walking. The geometry of the sole is important for a harmonious rolling behavior while walking. Likewise, energy return, usually achieved by passive spring elements, is desired when the forefoot is detached from the ground. This ensures energy-efficient walking of the prosthesis wearer.

In general, an individual, patient-specific design of the entire prosthesis is important in order to adapt the functional elements to the needs of the patient. However, conventional prosthetic feet only allow individual changes to a limited extent. In most cases, the prosthetic foot itself is not changed, but the orthopedic technician chooses a foot from the variety of different prosthetic feet that most closely corresponds to the desired properties. In addition, prosthetic feet are usually available in different sizes. Some can still be adjusted by, for example, replacing or adjusting damping elements.

Modern additively manufactured prosthetic feet offer the possibility of individually adapting each individual prosthetic foot due to the tool-free production. This means that not only the foot size can be adjusted, but also the damping properties and rolling behavior to a particularly high degree.

In addition, prosthetic feet must meet target-group-specific requirements. There are prosthetic feet that have been specially developed for the sports sector. Another example are older people who are more often in a stance phase than young people. In this case, a stable prosthetic foot optimized for standing is desired.

Previous methods are based on the fact that a specialist designs the prosthetic feet according to the requirements of the target group or the patient. It depends on the experience and skill of the specialist.

It is therefore an object of the invention to enable the production of fully individualized prosthetic feet that are tailored to the individual needs of individual patients. It is a particular object of the invention to reduce the number of prosthetic feet that are actually to be produced. It is a further particular object of the invention to keep the necessary computing resources low.

This object is achieved by a method according to claim 1, by a computer-readable storage medium according to claim 13 and by a system according to claim 14.

1. a) Parametrieren eines Prothesenfußmodells, das einen Prothesenfuß angibt, mit mindestens einem Eingabeparameter;
2. b) Berechnen von mindestens einem Lastfall des parametrierten Prothesenfußmodells zur Erzeugung von Lastfallergebnisdaten;
3. c) Anpassen mindestens eines freien Parameterwertes des parametrierten Prothesenfußmodells unter Berücksichtigung der Lastfallergebnisdaten;
4. d) Bestimmen eines optimierten Prothesenfußmodells unter Verwendung des mindestens einen angepassten freien Parameterwertes.

In particular, the object is achieved by a method for determining a prosthetic foot model which specifies a prosthetic foot, comprising the following steps:

1. a) parameterizing a prosthetic foot model that specifies a prosthetic foot with at least one input parameter;
2. b) calculating at least one load case of the parameterized prosthetic foot model for generating load case result data;
3. c) adapting at least one free parameter value of the parameterized prosthetic foot model taking into account the load case result data;
4. d) determining an optimized prosthetic foot model using the at least one adapted free parameter value.

A first core of the invention is that an optimized prosthetic foot model is determined taking into account individual input parameters. In particular, it is provided that the input parameters are designed as patent-specific input parameters. However, it is also possible for input parameters to be specified by standards, such as ISO standards. This makes it possible to meet the individual requirements of a single patient. For example, a patient can indicate that he desires a certain rolling behavior of the prosthetic foot. All of these requirements can be met with the specified procedure. Another core of the invention is that free parameters of the prosthetic foot model are adapted in such a way that an optimized prosthetic foot model is found as quickly as possible.

The steps of the method described above can be in any order or be carried out in exactly the order specified.

A prosthetic foot model in the context of this application can comprise, for example, a CAD model. In addition to CAD data, the prosthetic foot model can contain further information. For example, the prosthetic foot model can specify the changeable free parameters.

In one embodiment, the method can include minimizing a cost function that can indicate a deviation of the load case result data from reference load case result data, wherein the adjustment can be carried out taking the deviation into account.

Load case result data can, for example, indicate a force exerted on the prosthetic foot model at a specific position in a specific direction and with a specific force. For example, the load case result data may include at least one floor reaction force, i.e. specify a force that acts vertically away from a floor surface on the prosthetic foot. Load case result data can also indicate a variety of such applied forces. In particular, a complete rolling behavior of the parameterized prosthetic foot model can be specified by the generated load case result data and / or the reference load case result data. It is also possible for the load case result data to indicate an interpolation of discrete load case data. Load case result data can therefore include a discrete amount of data or a continuous description, e.g. a function, specify.

The reference load case data can be provided by an expert, a specification of the patient or relevant literature. With the described embodiment, the prosthetic foot model can be adapted such that the rolling behavior of the prosthetic foot model corresponds to the reference load case result data. The prosthetic foot model can thus be adapted to the patient's wishes.

In one embodiment, the generated load case result data and / or the reference load case result data can indicate a deformation of the parameterized prosthetic foot model and / or a position of a force application point, in particular a ground reaction force.

It is particularly advantageous if load case result data indicate a deformation of the parameterized prosthetic foot model. The deformation of a prosthetic foot is a crucial criterion for the comfort that a user of a prosthetic foot experiences when walking. It is therefore crucial for the comfort of the user that the deformation of the prosthetic foot is optimized. With the described method, it is possible to adapt the deformation of the prosthetic foot model in such a way that it corresponds to the wishes of a user.

It is also possible to adjust the position of force application points. In particular, different force application points are defined at any time during a rolling movement through the prosthetic foot. An at least two-dimensional ground reaction force vector and a force application point can be specified for each angle of attack. Like the deformation, the position of the force application point is an essential factor in the assessment of the comfort of a prosthetic foot by the user. Thus, the adaptation of the position of the force application point is a great advantage of the invention. The position of a force application point can indicate in a body-fixed coordinate system of the prosthetic foot model, at which point of the contact surface between the prosthetic foot model and the ground plane the force application vector is located. The force attack vector can specify a weighted center of gravity over all reaction forces between the prosthetic foot model and the floor level.

In further embodiments, it is additionally or alternatively possible to adapt an energy return, energy efficiency, joint forces, joint moments, joint angles, joint accelerations, lever arms and / or stiffness.

In one embodiment, the calculation of the at least one load case can include determining a multiplicity of force application points at different times and / or at different angles of attack, in particular during a rolling movement.

By calculating the at least one load case, it can be achieved with the described embodiment that the force application points are determined at a plurality of discrete times and / or angles of attack and are indicated by the load case result data. For example, a force application point can be determined at time intervals of less than 1 second, in particular less than 10 ms, preferably less than 1 ms, particularly preferably less than 0.1 ms. Furthermore, it is possible to determine a force application point and corresponding load case result data at intervals of less than or equal to 5 °, preferably less than or equal to 2 ° and particularly preferably less than or equal to 1 °, particularly preferably less than 0.5 °. Provision can be made to determine a total of at least 100, preferably 300, force application points.

This makes it possible to determine the overall rolling behavior of the prosthetic foot model. This enables a more precise adjustment of the prosthetic foot to the patient's wishes.

In one embodiment, the method can include calculating a deformation of the parameterized prosthetic foot model, in particular at different times of a rolling movement.

As already described with regard to the determination of force application points, a deformation of the parameterized prosthetic foot model can also be determined at discrete times of a rolling movement.

In one embodiment, the cost function can indicate a deviation of at least one specific deformation of the parameterized prosthetic foot model from an assigned reference deformation of the parameterized prosthetic foot model. A reference deformation can be assigned to a specific deformation taking into account the angle of attack and / or a time step.

The cost function to be minimized can be implemented in the described embodiment as the amount of the difference between the determined deformation and the reference deformation. The aim is to reduce this difference to a minimum. Thus, an easy-to-implement cost function is specified that can be optimized or minimized using known minimization methods.

In one embodiment, the cost function can indicate a deviation of at least one specific position from an assigned reference position of a force application point.

In addition to the deformation, the cost function can also determine the amount of the difference between at least one specific position of force application points and respectively assigned reference positions of force application points. The positions of the force application points can thus also be optimized in a simple manner.

In a further embodiment, the cost function can be specified by the product of the amounts of the deviation from a specific deformation and a reference deformation and a specific position and a reference position of at least one force application point.

• - Festlegen von mindestens einem Parameterbereich für mindestens einen Parameter eines Prothesenfußmodells, insbesondere für eine Federstärke und/oder eine Fußlänge;
• - Bestimmen einer Vielzahl von Kandidaten-Prothesenfußmodellen unter Verwendung eines Sampling-basierten Verfahrens und des mindestens einen Parameterbereichs, wobei die Vielzahl von Kandidaten-Prothesenfußmodellen das mindestens eine Prothesenfußmodell angibt.

In one embodiment, the method may further include:

• - Definition of at least one parameter range for at least one parameter of a prosthetic foot model, in particular for a spring strength and / or a foot length;
• Determining a plurality of candidate prosthetic foot models using a sampling-based method and the at least one parameter range, the plurality of candidate prosthetic foot models indicating the at least one prosthetic foot model.

To determine the prosthetic foot model, which is optimized, a large number of candidate prosthetic foot models can first be determined. This can be achieved in that the parameter space, which is specified by the different parameters of a prosthetic foot model, is sampled or sampled. Different candidate prosthetic foot models are thus generated in accordance with the sampling algorithm used.

The parameter space can be specified, for example, by the foot size, in particular the foot length and the foot width, the spring strength at different points in the prosthetic foot model, and the different distances between different parts of the prosthetic foot model.

Computing resources are thus saved with the described embodiment, since a particularly good prosthetic foot model is assumed, so that optimization can be carried out more quickly.

In one embodiment, the calculation of the at least one load case can be carried out using a finite element method.

Finite element processes have proven themselves in practice and can provide very precise information on the forces or deformations in workpieces. There are also common standard solutions for this, which make it possible to use the method efficiently.

In one embodiment, the calculation of the at least one load case can include determining an equivalent function which can specify a plurality of intermediate values of load case result data with different free parameter values, in particular intermediate values of deformation values and / or position values of force application points.

In one embodiment, the replacement function can be approximated, for example interpolated, using load case result data from at least one load case from at least two Candidate prosthetic foot models include, wherein the load case result data can be calculated in particular using different free parameter values.

In order to further shorten the necessary computing time, it is possible, using at least one load case, or the load case result data of this at least one load case, to determine an alternative function with which it is possible to approximate the load case result data of further candidate prosthetic foot models. For example, the substitute function can be determined by interpolation using the calculated load case data. If load case result data are now to be determined for a further candidate prosthetic foot model, the interpolation function, ie. H. the substitute function, another set of load case result data can be approximated.

In one embodiment, the replacement function can be determined taking into account at least 50 candidate prosthetic foot models, preferably at least 100 candidate prosthetic foot models.

In one embodiment, the method can furthermore control a production system using the optimized prosthetic foot model, which can be designed to manufacture a prosthetic foot.

It is therefore possible that the optimized prosthetic foot model is used directly to produce a prosthetic foot. For example, the production system can be designed as an additive production system, for example as a 3D printer. It is thus possible to provide a patient with an individually adapted and optimized prosthetic foot very quickly.

The object is also achieved in particular by a computer-readable storage medium which contains instructions which cause at least one processor to implement a method as described above if the instructions are executed by the at least one processor.

There are similar or identical advantages as have already been described in connection with the method.

• - mindestens eine Rechnereinheit mit mindestens einer Recheneinheit und einer Speichereinheit, insbesondere ein vorstehend beschriebenes Speichermedium;
• - eine Fertigungsanlage, wobei die Fertigungsanlage dazu ausgebildet ist, einen Prothesenfuß unter Verwendung eines Prothesenfußmodells, insbesondere eines optimierten Prothesenfußmodells, das nach dem vorstehend beschriebenen Verfahren bestimmt ist, zu fertigen.

The task is also solved in particular by a system comprising:

• - At least one computing unit with at least one computing unit and a storage unit, in particular a storage medium described above;
• a production system, the production system being designed to manufacture a prosthetic foot using a prosthetic foot model, in particular an optimized prosthetic foot model, which is determined according to the method described above.

There are similar or identical advantages as have already been described in connection with the method.

In one embodiment, it is further conceivable that the computer unit and the production system are communicatively connected to one another via the Internet. It is therefore not necessary for the computer unit and the production system to be arranged at the same location.

Further embodiments result from the subclaims.

• 1: eine schematische Darstellung eines Prothesenfußmodells 10;
• 2: eine schematische Darstellung von zwei Lastfällen;
• 3: eine schematische Darstellung, die den Kraftverlauf bei einem Abrollen eines Prothesenfußmodells 10 zeigt;
• 4: eine schematische Darstellung des Lösungsraums hinsichtlich von zwei Parametern des Prothesenfußmodells;
• 5: eine schematische Darstellung von bestimmten Kraftangriffspunkten und Deformationen des Prothesenfußmodells;
• 6: eine schematische Darstellung der Differenz der bestimmten Deformationswerte mit Referenzdeformationswerten;
• 7: ein Flussdiagramm, das das Verfahren erläutert; und
• 8: eine schematische Darstellung eines Systems mit einer Rechnereinheit und einer Fertigungsanlage.

The invention is explained in more detail below on the basis of exemplary embodiments. Show:

• 1 : a schematic representation of a prosthetic foot model 10th ;
• 2nd : a schematic representation of two load cases;
• 3rd : a schematic representation showing the force curve when rolling a prosthetic foot model 10th shows;
• 4th : a schematic representation of the solution space with regard to two parameters of the prosthetic foot model;
• 5 : a schematic representation of certain force application points and deformations of the prosthetic foot model;
• 6 : a schematic representation of the difference between the determined deformation values with reference deformation values;
• 7 : a flowchart explaining the method; and
• 8th : A schematic representation of a system with a computer unit and a manufacturing plant.

In the following, the same reference numerals are used for the same or equivalent parts.

1 shows a schematic representation of a prosthetic foot model 10th that via an adapter 11 can be connected to other components.

The basic body 13 is above a heel spring element 16 arranged that the heel of the prosthetic foot model 10th forms. The spring properties of the heel spring element 16 become decisive with a second spring element thickness 19th certainly. In addition, the behavior of the prosthetic foot model 10th when stepping on the heel by the first spring element thickness 17th certainly.

The prosthetic foot model 10th still has above the body 13 via an upper spring element 14 that of the main body 13 in the front area by a spring gap 15 is objected to. The spring gap 15 thus further defines the spring behavior of the prosthetic foot model 10th .

In the front area of the prosthetic foot model 10th is a front spring element 18th arranged, which in the embodiment shown has a longitudinal gap, so that the front spring element 18th is carried out in two parts. The spring properties of the two-part front spring element 18th is partly due to a third spring element thickness 20 specified.

The first, the second and / or the third spring element thickness 17th , 19th , 20 form free parameters for individualizing the prosthetic foot model 10th are customizable.

The 2nd shows a schematic representation of two exemplary load cases of the prosthetic foot model 10th at different times during a rolling process. A force acts in the first load case F1 orthogonal from a floor level B on the heel area of the prosthetic foot model 10th . It comes through the force F1 to a deformation of the prosthetic foot model 10th . An angle α gives the angle of attack of the prosthetic foot model 10th with respect to a reference plane R on.

With regard to the first load case, the deformation of the prosthetic foot model can 10th at a first point in time or for a first angle of attack α be determined. In addition, the position of a force application point can be used for the first load case 21 on the prosthetic foot model 10th be determined.

2nd also shows a second load case in which a force F2 orthogonal to the plane B affects the forefoot area. Here too there is a deformation of the prosthetic foot model 10th . The angle of attack of the prosthetic foot model 10th regarding the reference plane R is through the angle β specified.

The force application point or its position can therefore also be used for the second load case 22 can be specified.

In particular, the ground reaction force acting in the respective force application point can be specified.

The 3rd shows a schematic representation of a complete force curve during a rolling process of the prosthetic foot model 10th . The force curve shown here 30th the forces acting on the force application points (y-axis) and the assigned angles of attack α , β (x-axis).

In the course of force 30th are the load case result data 31 , 32 for the load cases of 2nd drawn. The force curve 30th is a complete description of the rolling behavior of the prosthetic foot model 10th across all angles of attack at which the prosthetic foot model 10th Has contact with the ground.

To the prosthetic foot model 10th Adapting the force curve to patient-specific requirements 30th adapted to a reference force curve. You can do this with free parameters of the prosthetic foot model 10th how the spring strength on the heel (second spring element thickness 19th ) or the spring strength in the toe area (third spring element thickness 20 ) be adjusted.

The 4th is a schematic representation of the solution space of an adaptation. The shows 4th a plot of results 40 that the result space 41 represents one axis 42 body weight, an axis 43 the heel thickness and an axis 44 indicates the heel deformation. Body weight is a patient-specific parameter, heel thickness is an adjustable free parameter, and heel deformation represents load case results data.

From a starting prosthetic foot configuration 45 is the optimization curve via an optimization process 47 determines the optimized prosthetic foot configuration after a series of iterations 46 indicates. So it applies in the solution space 41 to find a preferably global minimum.

The cost function to be minimized is indicated in the exemplary embodiment shown by: $$\begin{array}{l}F=(bestimmteDefOrmatiOndeserstenLastfalls31\\ -Referen\mathrm{e.g.}defOrmatiOnfürLastfall31)\\ \ast (bestimmteDefOrmatiOndes\mathrm{e.g.}weitenLastfalls32\\ -Referen\mathrm{e.g.}defOrmatiOndes\mathrm{e.g.}weitenLastfalls32)\end{array}$$

The optimum can be determined by executing a large number of finite element simulations iteratively, with at least one of the free parameters being adapted after each execution of the finite element simulation.

The 5 and 6 show an embodiment in which a deformation curve, which is determined via a rolling process, is adapted to a predetermined deformation curve. This is done in the 5 a course of force 30th specified, where a variety of load cases 51 is shown with circles. Any angle α , β so becomes a force F1 , F2 assigned to the prosthetic foot model 10th works. A deformation point can also be used for each angle on the X axis 53 be determined by a deformation D of the prosthetic foot model 10th indicates at a certain angle. This is with the graph 52 illustrated.

In addition to a deformation D can additionally or alternatively a position P of force application points 21 which are indicated by the rolling curve 54 is shown. The axes P and Z indicate a rigid coordinate system of the prosthetic foot model. The axis Z is the longitudinal axis of the foot and the axis P is concentric with the adapter 11 extending axis.

The 6 shows the deformation curve 52 compared to a reference deformation curve 55 . The reference deformation curve corresponds to the patient's wishes with regard to the behavior of the prosthetic foot model 10th . As from the 6 can be seen, for example, with regard to the amount of deformation at the deformation point 53 and the deformation at the reference deformation point 56 a difference. The aim of the optimization is therefore to minimize this difference. Thus, the function is the difference in the deformation curve 52 and the reference deformation curve 55 indicates the cost function to be minimized.

In addition to adapting a deformation curve 52 an adjustment of a position curve to a reference position curve can also be carried out analogously to a reference deformation curve.

The 7 shows a flow diagram illustrating the method for determining an optimized prosthetic foot model 10th or for the production of a prosthetic foot explained in detail. First, in a receive step 62 Input parameters 61 receive. For example, the patient's weight or size can be used as an input parameter 61 be received. In addition, a prosthetic foot model 10th receive.

In addition, in the receiving step 62 the prosthetic foot model 10th with the input parameters 61 and parameterized with free parameter values. So there will be a variety of candidate prosthetic foot models 63 generated for in the calculation step 64 at least one load case is calculated and corresponding load case result data 31 , 32 are generated, the rolling behavior of the parameterized prosthetic foot models 63 when the forces work F1 , F2 specify. In this embodiment, it is further assumed that the load case result data 31 , 32 in this embodiment also the deformation of the prosthetic foot model 10th specify.

In the comparison step 66 becomes the deformation behavior, which is determined by the load case result data 31 , 32 is specified with a reference deformation curve 55 compared and there will be a deviation 67 certainly. The candidate prosthetic foot model becomes the prosthetic foot model 10th selected which has the least deviation. In the test step 68 it is checked whether the deviation 67 for the prosthetic foot model 10th is within a tolerance interval, ie it is checked whether the parameterized prosthetic foot model 10th meets the patient's requirements.

It is determined that the deviation 67 is too large, the minimization step 69 determines how the free parameters, for example the first, the second or the third spring element thickness 17th , 19th , 20 must be adjusted to the deviation 67 to reduce.

In the adjustment step 70 becomes the prosthetic foot model 10th using the adjusted free parameters 17th , 19th , 20 parameterized again so that a parameterized prosthetic foot model 63 ' is obtained. Then it is checked again whether the parameterized prosthetic foot model has now been received 63 ' meets the patient's requirements.

Is in the test step 68 found that the parameterized prosthetic foot model 63 or 63 ' The optimized prosthetic foot model is sufficient for the patient's requirements 71 found. This can be done in the manufacturing step 72 used to make a prosthetic foot. For example, an additive manufacturing system can be used to fit a prosthetic foot according to the optimized prosthetic foot model 51 to manufacture.

The 8th shows a schematic representation of a system 80 which is a computing device 81 and an additive manufacturing facility 84 includes. The computing device 81 comprises a computing device 82 and a storage device 83 . The computing device 82 is designed to be an optimized prosthetic foot model 71 to generate according to the method described above and to control the additive manufacturing system such that a prosthetic foot 85 according to the optimal prosthetic foot model 71 will be produced.

In the additive manufacturing plant 84 it is a 3D printer in the present exemplary embodiment.

At this point it should be pointed out that all the parts described above are seen on their own and in every combination, especially in the Details shown in the drawings are claimed as essential to the invention. Modifications to this are familiar to the person skilled in the art.

Reference list

10th

Prosthetic foot model

11

adapter

13

Basic body

14

upper spring element

15

Spring gap

16

Heel spring element

17th

first spring element thickness

18th

front spring element

19th

second spring element thickness

20

third spring element thickness

21

Force application point in the heel area

22

Force application point in the forefoot area

30th

Roll curve

31

first load case result data

32

second load case result data

40

Score plot

41

Result space

42

Axis that indicates body weight

43

Axis that indicates the heel thickness

44

Axis that indicates heel deformation

45

Start prosthetic foot configuration

46

Optimized prosthetic foot configuration

47

Optimization curve

51

Load case

52

Deformation curve

53

Deformation point

54

Roll curve

55

Reference deformation curve

56

Reference deformation point

60

Flow chart for a method for determining a prosthetic foot model

61

Input parameters

62

Receiving step

63, 63 '

parameterized prosthetic foot model

64

Calculation step

66

Comparison step

67

deviation

68

Test step

69

Minimization step

70

Adjustment step

71

optimized prosthetic foot model

72

Manufacturing step

80

system

81

Computing device

82

Computing device

83

Storage device

84

Manufacturing facility

85

Prosthetic foot

F1

first force

F2

second force

X

Angle in degrees

Y

Force in Newtons

Z.

Longitudinal axis of the foot

D

deformation

P

axis

B

Ground level

R

Reference plane

α, β

Angle of attack

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 202015007994 [0002]
• DE 102014006727 B3 [0002]

Claims (14)

A method of determining a prosthetic foot model (60) indicating a prosthetic foot (85), comprising the following steps: a) parameterizing a prosthetic foot model (10), which indicates a prosthetic foot, with at least one input parameter (61); b) calculating (64) at least one load case of the parameterized prosthetic foot model (63) to generate load case result data (31, 32); c) adapting (70) at least one free parameter value (17, 19, 20) of the parameterized prosthetic foot model (10) taking into account the load case result data (31, 32); d) determining an optimized prosthetic foot model (71) using the at least one adapted free parameter value (17, 19, 20). Procedure according to Claim 1 , characterized by minimizing (69) a cost function which indicates a deviation (67) of the load case result data (31, 32) from reference load case result data (52), the adaptation (70) being carried out taking into account the deviation (67). Method according to one of the preceding claims, characterized in that the load case result data (31, 32) and / or the reference load case result data (52) a deformation (D, 53) of the parameterized prosthetic foot model (63) and / or a position of a force application point, in particular a ground reaction force Specify (51). Method according to one of the preceding claims, characterized in that the calculation (64) of the at least one load case (31, 32) comprises determining a plurality of force application points (51) at different times and / or at different angles of attack, in particular during a rolling movement. Method according to one of the preceding claims, characterized by calculating a deformation (D, 53) of the parameterized prosthetic foot model (63), in particular at different times of a rolling movement. Method according to one of the preceding claims, in particular according to Claim 3 characterized in that the cost function indicates a deviation (67) of a specific deformation (53) of the parameterized prosthetic foot model (63) from a reference deformation (56) of the parameterized prosthetic foot model (63). Method according to one of the preceding claims, in particular according to Claim 3 , characterized in that the cost function indicates a deviation (67) of at least one specific position from a reference position of the force application point (51). Method according to one of the preceding claims, characterized by - defining at least one parameter range for at least one parameter of a prosthetic foot model, in particular for a spring thickness and / or a foot length; - Determining a plurality of candidate prosthetic foot models using a sampling-based method and the at least one parameter range, the plurality of candidate prosthetic foot models indicating the at least one prosthetic foot model (10). Method according to one of the preceding claims, characterized in that the calculation (64) of the at least one load case (31, 32) is carried out using a finite element method. Method according to one of the preceding claims, characterized in that the calculation (64) of the at least one load case (31, 32) comprises determining an equivalent function which specifies a plurality of intermediate values of load case result data with different free parameter values (17, 19, 20) , in particular intermediate values of deformation values and / or position values of force application points. Method according to one of the preceding claims, in particular according to Claim 10 , characterized in that the determination of the substitute function comprises approximating, for example interpolating, using load case result data from at least one load case from at least two candidate prosthetic foot models, the load case result data being calculated in particular using different free parameter values. Method according to one of the preceding claims, characterized by actuation (72) of a production system (84) using the optimized prosthetic foot model (71), which is designed to manufacture a prosthetic foot (85). A computer readable storage medium (83) containing instructions that cause at least one processor (82) to implement a method according to any one of the preceding claims when the instructions are executed by the at least one processor (82). System (80), comprising: - at least one computing unit (81) with at least one computing device (82) and a storage unit (83), in particular a storage medium (83) Claim 13 ; - a production system (84), which is designed to a prosthesis foot (85) using a prosthetic foot model (71), in particular an optimized prosthetic foot model (71), which according to a method according to one of the Claims 1 to 12th is destined to manufacture.

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