Method for controlling a casting process, control system for a casting process, apparatus and computer program

Abstract

The present invention relates to a method for temperature control of a casting process, in particular a die casting process, comprising: determining at least one output variable indicatively for at least one temperature of a mold, wherein the at least one output variable is detected during an open state of the mold by means of at least one thermal imaging camera; controlling at least one input variable indicatively for at least one input variable of the casting process as a function of the output variable such that a temperature difference of at least one temperature of the mold to a preset temperature profile is minimized, wherein the at least one output variable is estimated during a closed state of the mold by means of a state estimator based at least on the output variable detected during the open state of the mold.The invention also relates to a control system for a casting process, in particular for a die casting process, a device and a computer program.

Description

[0001] The invention relates to a method for controlling, in particular temperature controlling, a casting process, especially a die casting process. The present invention also relates to a control system for a casting process, especially a die casting process, comprising at least one control means for controlling at least one input variable indicatively for at least one input parameter of the casting process, particularly as a function of at least one output variable indicatively for at least one temperature of the casting process, in particular for the temperature of a mold, more preferably for a temperature trajectory of the casting process or the mold, such that a temperature difference, in particular a predicted temperature difference, between the temperature of the casting process and a preset temperature profile is minimized. The present invention further relates to a device and a computer program.

[0002] Methods for temperature control in casting processes are already known from the prior art. Essentially, a distinction is made between two conventional control options: feedforward control and simple feedback control.

[0003] In forward-directed control, at least one input variable, which is indicative of at least one input parameter of the casting process, is preset by a process engineer before the respective casting cycles.

[0004] However, in practice, it has been shown that forward-directed control can lead to significant temperature fluctuations between individual casting cycles, which can result in defects and / or casting errors in the production of individual castings.

[0005] In simple feedback control, the flow rate of a coolant is regulated based on at least one measuring device, particularly a thermocouple, located in the mold. If, for example, the temperature measured by the thermocouple exceeds a preset temperature limit, a coolant flow is activated. This flow continues until the temperature measured by the thermocouple falls below another preset temperature limit. Such a control strategy, also known as bang-bang control, is possible in many commercial die-casting machines. While this method utilizes information from the casting process, especially the temperature measured by a thermocouple, the response time is slow because it can only react to temperature fluctuations that have already occurred.It has been shown that significant temperature spikes can occur with such a control system, especially shortly after the mold is filled with the mold filling or the melt.

[0006] Furthermore, the use of thermocouples within the mold has proven disadvantageous with regard to thermocouple maintenance. Additionally, it is very time-consuming to constantly check whether the measured values ​​output by the thermocouples are correct, which can further limit the functionality of the feedback control system.

[0007] Based on this, the present invention aims to provide a method for temperature control of a casting process, in particular a die casting process, which enables reliable temperature control of the casting process while avoiding high maintenance costs. Furthermore, a control system for a casting process, a device, and a computer program comprising program instructions are to be provided, which enable reliable temperature control of the casting process while avoiding high maintenance costs.

[0008] According to a first aspect of the invention, the aforementioned problem is solved in a aforementioned method by the fact that the method comprises the following steps: Determining at least one output variable indicatively for at least one temperature of a mold, wherein the at least one output variable is detected during an open state of the mold using at least one thermal imaging camera, wherein the at least one output variable is estimated during a closed state of the mold using a state estimator based at least on the output variable detected during the open state of the mold, and controlling at least one input variable indicatively for at least one input variable of the casting process as a function of the output variable such that a temperature difference of at least one temperature of the mold to a preset temperature profile is minimized.

[0009] Therefore, a method can be provided that enables temperature control of a casting process in a structurally advantageous manner. By capturing at least one output variable using at least one thermal imaging camera, the complex installation of multiple thermocouples within the mold is no longer necessary.

[0010] Using at least one thermal imaging camera, it is advantageous to determine or specify, in particular, output variables that are indicative of the temperature at several positions on the mold, especially at several positions within the mold, at the same time. This can significantly reduce maintenance effort, as one thermal imaging camera can replace a large number of thermocouples and their functionality can also be checked much more easily.

[0011] Furthermore, extensive tests and simulations have surprisingly revealed that intermittent measurement of at least one output variable, specifically only when the mold is open, leads to sufficient temperature control of the casting process based on the preset temperature profile. In particular, estimating at least one output variable while the mold is closed—a state in which no thermal imaging data is available—ensures sufficient temperature control with respect to the preset temperature profile.

[0012] The at least one output variable acquired by the at least one thermal imaging camera is, in particular, at least one measured value from the thermal imaging camera. For increased measurement accuracy, it is preferred that the at least one thermal imaging camera determines a plurality of output variables indicative of the temperature at different locations within the mold, and that the control of the at least one input variable and / or the estimation of the at least output variables is performed in the closed state of the mold based on the plurality of output variables.

[0013] The thermal imaging camera in question is, in particular, a detection device that enables the temperature of specific objects or areas of specific objects to be measured over a certain distance. Specifically, the thermal imaging camera is designed to receive infrared radiation. For example, the wavelength of the received infrared radiation can be in a wavelength range of approximately 3.5 µm to 15 µm.

[0014] Preferably, at least one input variable is controlled indicatively for at least one input parameter of the casting process. In particular, the at least one input variable is indicative of a coolant flow rate, wherein the coolant flows, for example, through channels arranged in the mold and thereby cools the mold. This enables reliable control of the mold temperature. For example, the at least one input variable can also be indicative of at least one heating rate of a heating element or heat source arranged in the mold. This allows for rapid adjustment of the mold temperature to a preset temperature profile.

[0015] For example, at least one input variable is indicative of at least one input quantity if it allows a conclusion to be drawn about the input quantity. In particular, at least one input variable can be measured values ​​and / or data indicative of at least one input quantity. For example, the input variable can be the input quantity itself or measured values ​​and / or data that represent the input quantity or from which the input quantity can be derived. For example, at least one input quantity can be the temperature of a coolant in Kelvin, in which case at least one input variable can also be the temperature of the coolant in Kelvin or other measured values ​​and / or data that represent the temperature of the coolant or from which the temperature of the coolant can be derived.The foregoing preferably also applies with regard to the at least one output variable, which is indicative of at least one mold temperature. In this respect, the at least one input variable refers specifically to the physical condition, for example, the temperature of the coolant in Kelvin, whereas the at least one input variable or the at least one output variable can also refer to measured values ​​and / or data that allow conclusions to be drawn about the at least one input variable or the at least one mold temperature, and / or that represent the at least one input variable or the at least one mold temperature. The input variables typically set are, for example, indicative of the flow rates of a coolant and / or the cooling times during a casting cycle.

[0016] Furthermore, it has proven particularly advantageous in practice if the control system regulates one, and especially another, input variable, wherein the other input variable is preferably indicative of at least one heating rate of a heating element or heat source arranged in the mold. This allows for rapid adjustment of the mold temperature to a preset temperature profile.

[0017] Using a state estimator, at least one output variable can be estimated if no measured output variable is available from the at least one thermal imaging camera, namely in particular when the mold is closed.

[0018] A state estimator is a component in control systems that estimates the internal state of a dynamic system, such as a casting process. For example, the state estimator determines at least one output variable during a closed state of the mold based on at least one recorded output variable from the past when the mold was open, as well as on at least one controlled input variable. The state estimator can use mathematical models and algorithms to calculate the best possible estimate of the at least one output variable during a closed state of the mold from the available data for the past output variables and the past or present input variables.

[0019] Another preferred embodiment is characterized in that the control of the at least one input variable is based on a model-based control algorithm, and that the model-based control algorithm is preferably designed as a state controller and / or as a model predictive controller.

[0020] For example, the model-based control algorithm can be based on a dynamic model of a temperature balance within the mold, where the dynamic model in particular requires an estimate and / or a value of the at least one output variable to control the at least one input variable.

[0021] A state controller can be, for example, a control system used to manage the state of a casting process using at least one input variable. For instance, the state controller works by estimating the current state of the system via at least one output variable. The estimated state can then be compared to a predetermined state, and the at least one input variable can be adjusted to change the estimated state towards the predetermined state.

[0022] A state controller typically uses, for example, feedback where the error between the current state and the specified target state is multiplied by a constant and used as a control signal. This constant, usually implemented as a matrix, particularly a feedback matrix, is often referred to as the controller gain and determines the strength of the control.

[0023] A model predictive controller is based, in particular, on a so-called MPC model. In model predictive control, the aim is to achieve a preset temperature profile, which is a target temperature profile. This preset temperature profile could, for example, simply be a desired constant temperature. The goal of the control system is to keep the measured and / or predicted temperature of the casting process, especially the temperature of the mold, as close as possible to the target temperature profile during or between casting cycles. To this end, the current state of the process can be monitored, for example, at discrete time intervals, by acquiring and / or estimating at least one output variable. Furthermore, the state of the process for a specific future time interval can be estimated and / or controlled.Model predictive control is therefore based on an optimization problem, namely to optimize the output variable with respect to the preset temperature profile by controlling at least one input variable.

[0024] For example, the optimization problem might involve a cost function, the goal of which is to minimize this cost function. The mold filling can be considered as a measured disturbance variable, along with at least one input variable. Preferably, at least two input variables are considered, which are preferably indicative of the flow rate of a coolant and the heating rate of a heat source.

[0025] An example of a cost function that can be optimized using model predictive control could be based on the following formula: V K ≙ ∑ I = 1 n PH ‖ y ^ k + i | k − r k + i ‖ Q i 2 + ∑ i = 0 n CH − 1 ‖ Δ u ^ k + i | k ‖ R i 2 + ∑ i = 0 n CH − 1 ‖ u ^ k + i | k ‖ s i 2 .

[0026] The first sum term penalizes in this case. ∑ i = 1 n PH ‖ y ^ k + i | k − r k + i ‖ Q i 2 for example, the temperature difference between the output variable indicative of a predicted temperature or indicative of a predicted temperature trajectory and a preset temperature profile. house k + i | k | | can, for example, correspond to the predicted temperature or the predicted temperature trajectory. For example, | house k + i | k | | using the transfer function G(s) described below and the input variables û k+ i l k calculated. Furthermore, it is preferred that the term r k + i corresponds to the preset temperature profile.

[0027] The second sum term ∑ i = 0 n CH − 1 ‖ Δ u ^ k + i | k ‖ R i 2 For example, changes in input variables are penalized. This can particularly affect changes in the flow rate of a coolant or the heating rate of a heat source. Δ û k+i | k This can, for example, specify the change in at least one input variable between time k+1 and the previous time.

[0028] The third sum term ∑ i = 0 n CH − 1 ‖ Δ u ^ k + i | k ‖ S i 2 For example, it directly penalizes the input variables. This ensures, in particular, that the absolute amount of coolant flow or the absolute heating rate of a heat source is minimized.

[0029] The degrees of freedom of the model predictive control or the optimization problem are determined by the variables n PH , new as well as the weighting matrices Q, R and S.

[0030] For example, the variable n PH specifies how many future time intervals the calculation should be performed for. A time interval can, for example, be in a range between 0.5 s and 10 s.

[0031] The variable n CH, for example, indicates for how many time intervals in the future at least one input variable can be changed.

[0032] Preferably, the variables n PH and n CH can be adjusted with respect to the underlying optimization problem. For example, it is preferred that the variable n PH specifies at least the duration of a casting cycle, which can last, for example, between 1 min and 10 min.

[0033] The weighting matrices Q, R, and S specify, in particular, the weighting of the individual sum terms in the overall assessment. For example, the weighting matrices Q, R, and S can be unit matrices with the constants q, r, and s on the diagonal. Such a design has proven advantageous in model predictive control for reducing complexity while achieving satisfactory results.

[0034] Another preferred embodiment is characterized in that the state estimator further estimates the at least one output variable during a closed state of the mold as a function of the at least one input variable. This enables an estimation of the at least one output variable during the closed state, since further known and / or measured quantities that influence the casting process, in particular the temperature of the mold in an open state and which influence the at least one input variable, are taken into account for the state estimation.

[0035] Another preferred embodiment is characterized in that the state estimator includes a Kalman filter and / or is specifically designed as a Kalman filter, and that the state of the at least one output variable during a closed state of the mold is calculated or estimated using the Kalman filter, particularly at defined time intervals. This allows the state of the casting process to be reliably calculated or estimated. In particular, the state of the casting process is calculated based on the acquisition of the at least one input variable in the past and / or present and the at least one output variable in an open state of the mold in the past. Using the current state of the casting process, the various future temperature trajectories can be calculated within the framework of model predictive control, on the basis of which the at least one input variable can be controlled.

[0036] For example, other state estimators can also be used that employ known stochastic methods for state estimation. In particular, the state estimator can be designed as an SMC filter, especially a particle filter. An SMC filter is based on the idea of ​​estimating a current but unknown probability density on a state space and deriving statements about the most probable state from this. A sufficient state estimation for the state of at least one output variable in a closed state of the mold can also be achieved using such a state estimator.

[0037] A further preferred embodiment is characterized in that the model-based control algorithm is based on a data set, wherein the data set particularly comprises measured values ​​from the at least one thermal imaging camera for the at least one output variable during an open state of the mold, and that a correlation between the at least one input variable and the at least one output variable, determined based on the data set, is used by the control algorithm to control the at least one input variable. Preferably, the data set comprises several input variables, in particular at least two different input variables.Alternatively and / or additionally, the control algorithm can also be based on a heuristic model. Optionally, correlations and / or interactions between the input variables can also be determined using the model-based control algorithm. By calculating the correlation and / or interactions of the input variables and / or the correlation with the output variable, the effect of a change in one variable on another can be reliably calculated.

[0038] For example, the aforementioned control algorithm can include a grey-box model. Alternatively, the control algorithm can also be purely data-based or based on principles known from the prior art, which are subsequently parameterized by data.

[0039] A grey-box model can be represented, for example, by the following formula: Y out s = ∑ k = 1 n G i s U in , i s .

[0040] Yout is preferably the output variable, which is indicative of at least one temperature of the casting process. Din, i preferably denote the various input variables, where a total of n different input variables are possible. For example, the various input variables can be in the Laplace domain. The function G;(s) is preferably a transfer function, which can be represented in particular by the following formula for the individual input variables: G i s = K i 1 + T i s 2 .

[0041] K is preferably specified as a gain factor of the respective input variable, where T i can in particular be a time constant.

[0042] It has been shown that the illustrated grey-box model provides an advantageous model for calculating the correlation between the at least one input variable and the at least one output variable.

[0043] A further preferred embodiment is characterized in that the data set includes historical data, in particular data from previously carried out casting trials and / or data from series production, wherein the data set is preferably extended by data recorded during the execution of the casting process, in particular by measured values ​​from the at least one thermal imaging camera for the at least one output variable during an open state of the mold, and / or wherein the control algorithm is parameterized by means of estimated values, wherein the control algorithm is preferably validated and / or extended during the execution of the casting process by recorded data, in particular by measured values ​​from the at least one thermal imaging camera for the at least one output variable during an open state of the mold.This allows the use of a data set that makes it possible to consider the correlation between at least one input variable, at least one output variable, and, for example, disturbance variables.

[0044] Another preferred embodiment is characterized in that the control algorithm considers at least one input variable and one output variable, as well as their correlation to each other. This allows the control algorithm to reliably calculate various possible temperature trajectories and control the at least one input variable in such a way as to minimize a temperature difference, particularly a predicted one, between the temperature of the casting process and a preset temperature profile. Furthermore, it is preferred that, in the case of multiple input variables, the model predictive control also considers the correlation between the multiple input variables.

[0045] Another preferred embodiment is characterized in that the control algorithm and / or the state estimator includes the opening state of the mold, the filling level of the mold, and / or a measurement inaccuracy of the at least one thermal imaging camera as a further input and / or disturbance variable, and that the control algorithm and / or the state estimator considers the correlation of the further input and / or the disturbance variable to the at least one input variable and / or the at least one output variable. This enables reliable control of the at least one input variable and / or the at least one input quantity, since the opening state of the mold, the behavior of the mold filling or deviations in the mold filling can also be included in the control as a measured disturbance variable and / or a measurement inaccuracy of the at least one thermal imaging camera.When dealing with mold filling as a disturbance variable, the timing of the mold filling, the composition of the mold filling, the quantity of the mold filling and / or the temperature of the mold filling can be particularly problematic.

[0046] Another preferred embodiment is characterized in that the at least one input variable is a coolant flow rate, a coolant temperature, a casting cycle duration, a mold filling quantity, a mold filling composition, a mold filling temperature, a mold filling time, a heat source temperature, and / or a heat source heating rate. This allows an input variable to be controlled indicatively for one of the aforementioned input variables such that the temperature difference between the casting process temperature and a preset temperature profile is minimized. It is preferred that each input variable is indicative of a specific input variable. Preferably, several of the aforementioned input variables can also occur multiple times, for example, if multiple cooling circuits for coolants are present during the casting process.

[0047] Particularly preferred is the at least one input variable that is indicative of the flow rate of a coolant. This allows the flow rate of a coolant to be controlled based on model predictive control in such a way as to minimize the aforementioned temperature difference.

[0048] Preferably, at least two input variables are controlled indicatively for two input parameters of the casting process. In practice, using two input variables has proven preferable with regard to control accuracy, where one input variable is preferably indicative of the coolant flow rate and the other preferably indicative of the heating rate of a heat source. This allows for adjustment of both the coolant flow rate and the heating rate of the heat source based on model predictive control.

[0049] Another possible embodiment is characterized in that at least one further output variable is indicative of at least one further temperature of the casting process by means of a thermocouple, in particular by means of a thermocouple arranged at least partially within the mold, and that the at least one input variable is controlled as a function of the at least one output variable and the at least one further output variable. This allows the at least one further output variable to be used for control, in particular for control during a closed state of the mold, thereby further improving the accuracy of the control.

[0050] Furthermore, it is possible for the state estimator to estimate at least one output variable, particularly during a closed state of the mold, as a function of at least one other output variable. This can further improve the accuracy of the state estimator.

[0051] Furthermore, the state estimator can also estimate at least one output variable during an open state of the mold as a function of at least one other output variable. This is because the advantages of both measuring instruments can be combined by using at least one thermal imaging camera and at least one thermocouple in parallel. For example, a thermal imaging camera typically provides a more accurate temperature reading, whereas a thermocouple is usually more robust and reliable. Moreover, it may not always be possible to measure the temperature at the desired location. Therefore, combining the two measuring instruments can further improve the results of the state estimator.

[0052] According to a second aspect of the present invention, the aforementioned problem is solved in a control system for a casting process by the fact that the control system further comprises at least one thermal imaging camera for detecting the at least one output variable during an open state of the mold, and that the at least one control means estimates the at least one output variable during a closed state of the mold by means of at least one state estimator based at least on the output variable detected during the open state of the mold.

[0053] A control system can be, for example, a device for evaluating data, controlling other devices, and / or outputting signals. The control system can, for example, be part of a casting device, a casting fixture, and / or a casting plant.

[0054] The control system can comprise hardware and / or software components. For example, the control system can include at least one memory containing program instructions of a computer program and at least one processor configured to execute program instructions from that memory. Accordingly, control devices that include at least one processor and at least one memory containing program instructions, wherein the memory and the program instructions are configured, together with the processor, to control the at least one input variable, are also considered disclosed. The control of the at least one input variable is achieved, for example, via a control connection.

[0055] According to a preferred embodiment, the control system regulates, as at least one input variable, a coolant flow rate, a coolant temperature, a casting cycle duration, a mold fill quantity, a mold fill composition, a mold fill temperature, a mold fill time, a heat source temperature, and / or a heat source heating rate. The control system can also regulate at least two or more of the aforementioned input variables.

[0056] Preferably, the control system is designed to carry out a previously described procedure.

[0057] According to a third aspect of the present invention, the aforementioned problem is solved by a device comprising at least one processor and at least one memory containing program code, in that the memory and the program code are configured to cause the device to execute and / or control at least the aforementioned method. It is possible to either control all steps of the method, or execute all steps of the method, or control one or more steps and execute one or more steps.

[0058] In an exemplary embodiment, the device according to the third exemplary aspect of the present invention comprises at least a control system according to the second aspect of the present invention and a casting system suitable for carrying out a method according to the first aspect of the present invention.

[0059] The aforementioned problem is also solved according to a fourth aspect of the present invention by a computer program comprising program instructions that cause a processor to execute and / or control the aforementioned method when the computer program is running on the processor. For the purposes of this specification, a processor shall include, but is not limited to, control units, microprocessors, microcontrol units such as microcontrollers, digital signal processors (DSPs), application-specific integrated circuits (ASICs), or field-programmable gate arrays (FPGAs). It is possible to control all steps of the method, execute all steps of the method, or control and execute one or more steps.The computer program can be distributed, for example, via a network such as the internet, a telephone or mobile network, and / or a local area network. The computer program can be at least partially software and / or firmware of a processor. It can also be at least partially implemented as hardware. The computer program can be stored, for example, on a computer-readable storage medium, such as a magnetic, electrical, electromagnetic, optical, and / or other type of storage medium. The storage medium can be, for example, part of the processor, such as the processor's (non-volatile or volatile) program memory or a portion thereof. The storage medium can be, for example, physical, i.e., tangible, and / or non-transient.

[0060] The embodiments and exemplary configurations of all aspects of the present invention described above, which initially stand on their own, are also to be understood as being disclosed in all combinations with one another.

[0061] Further advantageous exemplary embodiments of the aspects of the invention can be found in the following detailed description of some exemplary embodiments of the present invention, particularly in conjunction with the figure. However, the figure accompanying the application is intended only for illustrative purposes and not to determine the scope of protection of the invention. The accompanying drawing merely reflects the general concept of the present invention by way of example. In particular, features included in the figure should by no means be understood as a necessary component of the present invention.

[0062] The invention will now be explained using exemplary embodiments with reference to the drawing. The drawing shows Fig. 1 shows exemplary temperature profiles based on different temperature control systems and different measurements of at least one output variable.

[0063] Fig. 1 shows different temperature profiles based on different temperature control regulations and different measurements of at least one output variable, as well as a preset temperature profile 2.

[0064] In addition to the preset temperature profile 2, two temperature profiles 4 and 6 are specified, based on a model predictive controller. Temperature profile 4 uses a continuous measurement of at least one thermocouple located in the mold to measure the output variable indicatively for at least one mold temperature. Temperature profile 6 uses a discontinuous measurement of the output variable in an open mold state using a thermal imaging camera. For temperature profile 6, the at least one output variable is estimated indicatively for at least one mold temperature in a closed mold state using a state estimator, since in such a case no information from the at least one thermal imaging camera is available indicatively for at least one mold temperature.

[0065] The grey shaded areas 8 of the graph correspond in particular to the time periods in which the mold is in an open state and therefore an output variable indicative of a temperature of the mold by means of which at least one thermal imaging camera can be recorded.

[0066] In contrast, the white areas 10 are those areas in which the mold is closed and therefore no output variables indicative of a mold temperature are provided by at least one thermal imaging camera and at least one output variable is therefore calculated by a state estimator during this period.

[0067] Furthermore, two additional temperature profiles 12 and 14 based on a simple PI controller are shown. Temperature profile 12 is based on a continuous measurement of at least one thermocouple located in the mold to measure the output variable. Temperature profile 14 is based on a discontinuous measurement of at least one output variable, indicative of at least one mold temperature in an open state, using at least one thermal imaging camera. In temperature profile 14, the PI controller is only active when the mold is open; when the mold is closed, a preset flow profile is used.

[0068] The square root of the mean square error - which is a commonly used parameter for evaluating the respective regulation. For the preset temperature profile 2, the temperature profiles shown during the period are 12.3°C for temperature profile 4, 14.3°C for temperature profile 6, 14.7°C for temperature profile 12, and 18.9°C for temperature profile 14.

[0069] Although it is apparent that relying on information from at least one thermal imaging camera leads to a certain deterioration in control performance, the control performance is still satisfactory even when using at least one thermal imaging camera and is therefore preferable, since using at least one thermal imaging camera avoids the need for costly installation and maintenance of multiple thermocouples.

[0070] Furthermore, it is evident that the model predictive controller leads to significantly more accurate control than a simple PI controller, since the model predictive controller can, even with a closed mold, use a state estimator to estimate at least one output variable indicatively for the mold temperature. This estimated output variable can then be used to control at least one input variable and thus the mold temperature. A simple PI controller, in such a case, can only switch to purely forward-directed control.

[0071] As an input variable indicative of an input quantity, in the following Fig. 1 The regulations shown indicate that an input variable is controlled indicatively for a flow rate of a coolant.

[0072] The exemplary embodiments of the present invention described in this specification are to be understood as being disclosed in all combinations with one another. In particular, the description of a feature included in an embodiment – ​​unless explicitly stated otherwise – is not to be understood as meaning that the feature is indispensable or essential for the function of the embodiment.

[0073] Terms used in the claims, such as "comprise," "have," "include," "contain," and the like, do not exclude further elements or steps. The phrase "at least partially" covers both "partially" and "completely." The phrase "and / or" is to be understood as disclosing both the alternative and the combination; thus, "A and / or B" means "(A) or (B) or (A and B)." A plurality of units, persons, or the like, in the context of this specification, means multiple units, persons, or the like. The use of the indefinite article does not preclude a plurality. A single device or means can perform the functions of several units or devices mentioned in the claims. Reference numerals specified in the claims are not to be considered as limitations on the means and steps employed.

Claims

1. A method for temperature control of a casting process, in particular a permanent mold casting process, comprising: - determining at least one output variable indicative of at least one temperature of a casting mold, - wherein the at least one output variable is detected by means of at least one thermal imaging camera while the casting mold is open, - wherein the at least one output variable is estimated by means of a state estimator during a closed state of the casting mold based at least on the output variable detected while the casting mold is open, and - controlling at least one input variable indicative of at least one input variable of the casting process as a function of the output variable such that a temperature difference between at least one temperature of the casting mold and a preset temperature profile is minimized.

2. Method according to claim 1, characterized by - thatthe control of at least one input variable is based on a model-based control algorithm, and - that the model-based control algorithm is preferably designed as a state controller and / or as a model predictive controller.

3. Method according to claim 1 or 2, characterized by - that the state estimator further estimates the at least one output variable during a closed state of the mold as a function of the at least one input variable.

4. Method according to one of claims 1 to 3, characterized by - that the state estimator comprises a Kalman filter and / or is designed in particular as a Kalman filter, and - that the state of the at least one output variable is calculated during a closed state of the casting mold by means of the Kalman filter, in particular in defined time intervals.

5. Method according to one of claims 1 to 4, characterized by - thatthe model-based control algorithm is based on a data set, wherein the data set comprises in particular measured values of the at least one thermal imaging camera for the at least one output variable during an open state of the casting mold, and - that by means of the control algorithm, a correlation determined based on the data set between the at least one input variable and the at least one output variable is used to control the at least one input variable.

6. Method according to claim 5, characterized by - that the data set comprises historical data, in particular data from previously conducted casting tests and / or data from series production, wherein the data set is preferably extended by data acquired during the execution of the casting process, in particular by measured values of the at least one thermal imaging camera for the at least one output variable during an open state of the casting mold, and / or - thatthe control algorithm is parameterized by means of estimated values, wherein the control algorithm is preferably validated and / or expanded during the execution of the casting process by recorded data, in particular by measured values of the at least one thermal imaging camera for the at least one output variable during an open state of the casting mold.

7. Method according to one of claims 1 to 6, characterized by - that the control algorithm takes into account at least one input variable and one output variable as well as their correlation with each other.

8. Method according to claim 7, characterized by - that the control algorithm, in particular the state estimator, further includes an opening state of the casting mold, a filling of the casting mold and / or a measurement inaccuracy of the at least one thermal imaging camera as a further input and / or disturbance variable, and - thatthe control algorithm takes into account the correlation of the further input and / or the disturbance variable to the at least one input variable and / or the at least one output variable.

9. Method according to one of claims 1 to 8, characterized by - that the at least one input variable is a flow rate of a coolant, a temperature of a coolant, a duration of a casting cycle, an amount of a casting mold fill, a composition of a casting mold fill, a temperature of a casting mold fill, a time of a casting mold fill, a temperature of a heating source and / or a heating rate of a heating source.

10. Method according to one of claims 1 to 9, characterized by - that at least one further output variable indicative of at least one further temperature of the casting process is detected by means of a thermocouple, in particular by means of a thermocouple arranged at least partially within the casting mold, and - thatthe at least one input variable is controlled as a function of the at least one output variable and the at least one further output variable.

11. Control system for a casting process, in particular for a permanent mold casting process, comprising: - at least one control means for regulating at least one input variable indicative of at least one input variable of the casting process as a function of at least one output variable indicative of at least one temperature of the casting process, in particular for a temperature of a casting mold, such that a temperature difference between the temperature of the casting process and a preset temperature profile is minimized, characterized by - that the control system further comprises at least one thermal imaging camera for detecting the at least one output variable during an open state of the mold, and - thatthe at least one control means estimates the at least one output variable during a closed state of the mold by means of a state estimator based at least on the output variable detected during the open state of the mold.

12. Control system according to claim 11, characterized by - that the control system regulates as at least one input variable a flow rate of a coolant, a temperature of a coolant, a duration of a casting cycle, an amount of a casting mold fill, a composition of a casting mold fill, a temperature of a casting mold fill, a time of a casting mold fill, a temperature of a heating source and / or a heating rate of a heating source.

13. Control system according to claim 11 or 12, characterized by - that the control system is designed to carry out a method according to one of claims 1 to 10.

14. A device comprising at least one processor and at least one memory containing program code, wherein the memory and the program code are configured to cause a device with the at least one processor to execute and / or control at least the method according to one of claims 1 to 10.

15. A computer program comprising program instructions that cause a processor to execute and / or control the method according to one of claims 1 to 10 when the computer program is running on the processor.

Images