Safety system for detecting errors in medical tables

Abstract

System for detecting an error of a sensor in an operating table and / or an error when determining a load or a load centre of gravity, comprising: an operating table with an adjustable patient bearing surface for bearing a patient; a load sensor arrangement having a plurality of load sensors which output sensor values; a load determination unit which determines at least one of the following first variables on the basis of the sensor values: a load, a centre of gravity of the load, a velocity of the load centre of gravity and an acceleration of the load centre of gravity, wherein the load is a load acting on the load sensor arrangement or a load acting on the operating table or a total load of the operating table; a calculation unit which predicts or calculates at least one expected second variable; and an error detection unit which compares the sensor values or the at least one first variable with the at least one expected second variable and detects an error and / or a possible error if the discrepancy exceeds a predefined value.

Description

[0001]Safety system for detecting errors in medical tables This application claims priority from German patent application No. 10 2022 110 888.0, filed with the German Patent and Trademark Office on May 3, 2022. The disclosure of German patent application No. 102022110888.0 is hereby incorporated into the disclosure of the present application. Technical field The present disclosure relates to medical and surgical tables in which the table top and / or segments of the table top are movable. In particular, it concerns systems that can detect errors that can occur in medical tables. The errors can be, for example, errors in sensors integrated into the tables or errors that occur when determining a load or a load center of gravity.Background to the disclosure Operating tables are used to position a patient, for example during a surgical procedure. Currently, due to the flexibility in setting up the operating table, the number of accessories and the various patient positioning options offered by the operating table, nurses and doctors must consider many important aspects in order to use the operating table correctly. Some of these aspects are listed below: - The accessories used should be adapted to the patient's weight. - The configuration of the accessories should also be adapted to the patient's weight. - The patient support surface on which the patient lies should only be moved within permitted limits. - If a movement restriction applies, care should be taken not to exceed the permitted limits at any time.- When moving the operating table, care should be taken to ensure that the operating table does not collide with an external object, such as a C-arm. - Furthermore, when moving the operating table, care should be taken to ensure that the patient is properly secured and does not fall or slip off the operating table. Important information on the points listed above can be found in the operating table's instructions for use. If the user ignores the instructions for use or does not pay sufficient attention to collisions and the patient, the following dangerous events may occur: - Tipping over of the operating table: The patient may fall, which could result in permanent injury or even death. - Overloading of structural parts of the accessories and the operating table: This could cause structural parts to permanently bend or break, causing permanent injury or even death to the patient.- Overload of the motorized joints: Causes limited mobility, as the operating table cannot move. - Collision of the operating table with an external object: During movement, the operating table can collide and damage expensive equipment, e.g., C-arms. - Patient fall: If the patient is not adequately secured, the patient may begin to slip during table movements, which in the worst case can lead to the patient falling to the floor. Patient support surfaces on operating tables can have replaceable, detachably connectable segments. Often, some or all of the replaceable segments are movable. By using various interchangeable segments, a single operating table can be reconfigured in different ways for different patients and medical procedures. Furthermore, individual segments or the entire patient support surface can be adjusted in various ways.For example, individual segments or the entire patient support surface can be tilted or tilted, or shifted longitudinally or vertically. However, this means that the size, shape, dimensions, weight, and strength of individual operating tables vary at different times. To prevent tipping of the operating table or overloading of individual structural components or the entire operating table, it is important to know the position of the patient support surface and its segments, the load acting on the patient support surface or the entire operating table, and the center of gravity of this load.For this purpose, operating tables can be equipped with various sensors that measure, for example, the load acting on the operating table or determine the angle at which the patient support surface is tilted or canted, or the distance the patient support surface has been extended. Such sensors must be fail-safe; otherwise, patient safety cannot be guaranteed. If a sensor fails and provides bad information, the system should detect this. Furthermore, a user should be warned that certain systems are unreliable and the operating table is in a safety-critical state. Furthermore, certain functionalities of the operating table could be blocked, and movement of the operating table could be slowed down or stopped completely. One solution to the problem described is to use a second set of redundant sensors.If one of the sensors were to fail, this would be detected by the second, redundant sensor. However, redundant sensors are very cost-intensive and often cannot be used due to insufficient space in the operating tables. The document US 11058325 B2 discloses a patient support device with a patient support surface, a primary sensor, several secondary sensors, a primary controller, and a secondary controller. The primary sensor is a load sensor that measures forces exerted on a component of the patient support surface. The primary controller receives the force measurements from the primary sensor. The secondary sensors measure several secondary parameters that can influence the force measurements performed by the primary sensor.The secondary sensors may include a humidity sensor, a pressure sensor, a gyroscope, a magnetometer, an accelerometer, a velocity sensor, a temperature sensor, or an angle sensor. The secondary controller processes the outputs of the secondary sensors to detect whether the force applied to the component of the patient support device is outside a range of force values. US 11058325 B2 does not disclose an operating table system as disclosed here that determines a load acting on the load sensor assembly or the patient support surface, a center of gravity of the load, a velocity of the center of gravity of the load, or an acceleration of the center of gravity of the load as a first quantity and predicts or calculates another expected second quantity, detecting an error if the two quantities deviate too greatly from each other.Document US 7472439 B2 discloses a patient support system that can be used in hospitals. A diagnostic and control system can monitor or query the functionality or status of electronic elements, for example load sensors. The diagnostic and control system can monitor the current status of the operating parameters of these electronic elements and compare the collected data with a set of standard operating characteristics. In this way, possible errors can be detected if a particular electronic element does not operate within a desired and / or predetermined range. US 7472439 B2 does not disclose that an expected value is calculated from the operating parameters of the electronic elements, which is compared with the operating parameters. Document WO 2017003766 A1 describes a personnel support device.Load sensors are integrated into the device and are connected to a detection circuit. The detection circuit can be used to determine whether the load sensors are malfunctioning. Two load sensors can be provided, each coupled to an activation line. An activation voltage source applies a constant voltage to the two activation lines. In one embodiment, a controller monitors a total amount of electrical current flowing from the activation voltage source to the activation lines. The controller determines that one of the load sensors is in a fault state if the total amount of electrical current flowing from the activation voltage source to the activation lines is outside a predetermined range.WO 2017003766 A1 does not disclose that a further expected value is calculated from the load or the load center determined with the aid of load sensors, and that an error is detected if the calculated expected value deviates too greatly from the determined load or the load center. Summary of the Disclosure: It is an object of the present disclosure to provide a system that is advantageously configured to detect a faulty sensor in an operating table. Additionally or alternatively, the system should be configured to detect an error that may occur when determining a load or a load center of the operating table.According to a first aspect of the present disclosure, a system is provided which is designed to detect a malfunctioning sensor in an operating table and / or to detect an error in the determination of a load or a load center of gravity. The system can comprise an operating table with an adjustable patient support surface, a load sensor arrangement with a plurality of load sensors, a calculation unit, and an error detection unit. The patient support surface of the operating table serves to support a patient, for example, during a surgical procedure. The patient support surface can be modular and have a main support surface section which can be expanded by coupling various secondary support surface sections.For this purpose, the main support surface section and the secondary support surface sections can have mechanical connecting elements with which the main and secondary support surface sections can be detachably connected. Secondary support surface sections can be, for example, leg or head sections. Furthermore, secondary support surface sections can also be extension or intermediate sections that are inserted, for example, between the main support surface section and the head section. The load sensors can output sensor values ​​from which a load acting on the load sensor arrangement and, in addition, also a load acting on the patient support surface can be determined. The load acting on the load sensor arrangement can, in particular, include all external force variables, i.e., forces and moments, that act on the load sensor arrangement.The load sensors can, for example, be force sensors, in particular load cells, each of which measures a force acting on the respective sensor. The force sensors can each output an electrical signal, for example an electrical voltage, from which the respective measured force can be derived. Furthermore, it can also be provided that the force sensors each output the specific magnitude of the force measured by them, for example in digital form, as a sensor value. It is also conceivable for the load sensor arrangement to determine a resulting total force from the sensor values ​​of the individual load sensors, wherein the resulting total force results from the individual forces acting on the various force sensors.The load acting on the load sensor arrangement includes, for example, the load caused by the components of the operating table arranged above the load sensor arrangement, as well as the load caused by the patient placed on the operating table or other objects located on the operating table. Furthermore, a person can also cause a load on the operating table, for example by standing next to the operating table and supporting themselves on the operating table with a hand or another body part. In addition, external forces generated in other ways can create a load on the operating table. Such loads can also be measured by the load sensor arrangement. The load sensor arrangement can be arranged at different positions in the operating table. For example, the load sensor arrangement can be integrated into the column of the operating table.Furthermore, the load sensor arrangement can be arranged at or adjacent to interfaces formed by the column with the patient support surface or the base (or the base). Consequently, the load sensor arrangement can be arranged, for example, between the patient support surface and the column. Alternatively, the load sensor arrangement can be arranged, for example, between the column and the base. The load sensor arrangement can be integrated into the operating table in such a way that the entire load flows through or is transmitted through the load sensor arrangement. In particular, the load that is caused above the load sensor arrangement can flow through or be transmitted through the load sensor arrangement. The load determination unit can be coupled to the load sensor arrangement and receive the sensor values ​​output by the load sensors. Based on the sensor values, the load determination unit can determine at least a first variable, iedetermine exactly one or more first quantities. The first quantity can be a load, a center of gravity of the load, a speed of the center of gravity of the load, or an acceleration of the center of gravity of the load. The load can be a load acting on the load sensor arrangement, a load acting on the operating table, or a total load of the operating table. The load acting on the load sensor arrangement can also be referred to as the measured load. The measured load corresponds to the load generated by all people, objects, and forces on the operating table above the load sensors. The measured load corresponds to the load value measured by the load sensor arrangement. The load acting on the operating table can be referred to as the effective load and corresponds to the load caused by components not associated with the operating table, by people, and by external forces acting on the operating table.Components assigned to the operating table are components that are recognized by the operating table using a detection system, e.g., table surface sections or segments and / or other accessories. The influence of the components assigned to the operating table is not taken into account in the effective load. Only the other components of the operating table, i.e., the components not assigned to the operating table, contribute to the effective load. These can be, for example, accessories that are not recognized by the operating table or other objects placed on the operating table. Furthermore, the patient on the operating table contributes to the effective load. All external forces acting on the operating table, for example, forces exerted on the operating table by people and / or objects outside the operating table, also contribute to the effective load.The total load of the operating table is the load resulting from the measured load and from a load caused by components assigned to the operating table and located below the load sensor array. The total load therefore takes into account loads from components located below the load sensor array that cannot be measured by the load sensor array and therefore do not contribute to the measured load. The total load is therefore the load resulting from the entire operating table, the patient, the components assigned to the operating table, the components not assigned to the operating table, and other external forces.In summary, the at least one first variable determined by the load determination unit can be selected from the following variables: - the measuring load, the center of gravity of the measuring load, the speed of the center of gravity of the measuring load, and the acceleration of the center of gravity of the measuring load; - the effective load, the center of gravity of the effective load, the speed of the center of gravity of the effective load, and the acceleration of the center of gravity of the effective load; and - the total load, the center of gravity of the total load, the speed of the center of gravity of the total load, and the acceleration of the center of gravity of the total load. The calculation unit can calculate or predict at least one expected second variable. The at least one expected second variable can be an estimated and / or predicted variable and can be a time-dependent or time-independent expected value.For example, the at least one expected second variable can be calculated directly from the at least one first variable, or the at least one first variable can first be subjected to further processing and the at least one expected second variable can be calculated from the result of the further processing. It can be provided that the at least one expected second variable is calculated or predicted after the at least one first variable. However, the at least one expected second variable can also be calculated or predicted before the at least one first variable. The terms “first variable” and “second variable” only serve to distinguish between the two variables. This does not state which of the two variables is calculated, determined, or predicted first. In some embodiments, the calculation unit can only predict the at least one expected second variable and, in particular, cannot calculate it.In some embodiments, the calculation unit can only calculate the at least one expected second variable and in particular cannot predict it. The error detection unit can compare the value determined by the load sensor arrangement or the load determination unit and the expected value determined by the calculation unit. To do this, the error detection unit can compare the sensor values ​​or at least one first variable determined by the load determination unit with the at least one expected second variable. The at least one first variable included in this comparison can be the at least one first variable from which the at least one expected second variable was calculated. However, for example, at least one first variable determined by the load determination unit at a different, in particular later, time can also be used for the comparison with the at least one expected second variable.If the comparison shows that the deviation of the at least one expected second variable from the sensor values ​​or the at least one first variable exceeds a predetermined value, i.e. the difference between the at least one expected second variable and the sensor values ​​or the at least one first variable is greater than the predetermined value, the error detection unit can determine that an error and / or a possible error exists. The error can be a faulty sensor, i.e. a sensor that is not functioning correctly, or an error that occurs when determining the load or the load center of gravity. The error detection unit makes it possible to warn the user of the operating table when a safety-critical condition occurs in order to ensure patient safety. Furthermore, measures can be taken to avert or prevent the safety-critical condition.The system described here does not require a complete additional sensor set to detect an error, nor does it necessarily require an additional hardware unit. Both the calculation and the error detection unit can be implemented as software functions. However, it is also conceivable for the calculation and / or the error detection unit to be designed as hardware units. Furthermore, the calculation unit and / or the error detection unit can either be integrated into the operating table or located outside the operating table. One or both units can, for example, be integrated into a computing unit that is located outside the operating table and is connected to the operating table, for example, via radio or fixed cabling.According to a second aspect of the present disclosure, when the patient support surface is adjusted, the calculation unit can predict the load center of gravity changed by the adjustment as the at least one second variable. Furthermore, the load determination unit can determine the load center of gravity after the adjustment of the patient support surface based on the sensor values. The load center of gravity determined by the load determination unit after the adjustment of the patient support surface can be used by the error detection unit as the at least one first variable. The error detection unit can compare the center of gravity predicted by the calculation unit with the center of gravity determined by the load determination unit after the adjustment of the patient support surface.If the deviation of the center of gravity predicted by the calculation unit from the center of gravity determined by the load determination unit exceeds the specified value, the error detection unit can detect an error and / or a potential error. As explained above, the error can be a faulty sensor, i.e., a malfunctioning sensor, or an error that occurs during the determination of the load or the load center of gravity. The present embodiment requires that the patient support surface be adjusted; only then can an error be detected. The patient support surface can be adjusted, for example, by tilting or canting the patient support surface, or by moving it longitudinally or vertically.A trend of the patient support surface is also known as a Trendelenburg tilt, in which the patient is positioned so that the patient's head is at the bottom and the patient's pelvis is higher. With an anti-Trendelenburg tilt, the patient's head is higher while the pelvis is lower. Tilt means that the patient support surface is tilted to the side. With a longitudinal shift, the patient support surface is shifted along its main axis, while with a lateral shift, the patient support surface is shifted perpendicular to its main axis. The system can further comprise an optional state estimation unit which estimates an actual center of gravity of the load based on the center of gravity predicted by the calculation unit and the center of gravity determined by the load determination unit.In some embodiments, the inputs to the state estimation unit, i.e. the center of gravity predicted by the calculation unit and the center of gravity determined by the load determination unit, can be weighted. For example, the center of gravity predicted by the calculation unit and the center of gravity determined by the load determination unit can contribute equally, i.e. 50% each, to the actual load center of gravity estimated by the state estimation unit. Other ratios between the center of gravity predicted by the calculation unit and the center of gravity determined by the load determination unit can also be selected. For example, it can be provided that the estimated actual load center of gravity corresponds 100% to the center of gravity determined by the load determination unit. In this case, the prediction made by the calculation unit would have no influence on the estimated actual load center of gravity.The state estimation unit can be a pure software function, but it can also be implemented as a hardware unit. Furthermore, the state estimation unit can be integrated into the operating table or located outside the operating table and, for example, integrated into the computing unit described above. The state estimation unit can have a Kalman filter for estimating the actual load center of gravity. In particular, the Kalman filter can be an extended Kalman filter or an unscented Kalman filter. The calculation unit, the load determination unit, and the state estimation unit can work iteratively. The state estimation unit estimates the actual load center of gravity at time t, and the calculation unit predicts the load center of gravity at time t+1 based on the actual load center of gravity at time t estimated by the state estimation unit. Furthermore, the load determination unit determines the load center of gravity at time t+1.The state estimation unit then estimates the actual load center at time t+1 based on the load center predicted by the calculation unit at time t+1 and the load center determined by the load determination unit at time t+1. The iterative process can be continued in the same way by the calculation unit predicting the load center at time t+2 based on the actual load center estimated by the state estimation unit at time t+1, and the state estimation unit then estimating the actual load center at time t+2 based on the load center predicted by the calculation unit at time t+2 and the load center determined by the load determination unit at time t+2.The error detection unit can detect an error and / or a potential error if a number of iterations have been performed and the error detection unit has determined in at least N of the iterations that the center of gravity predicted by the calculation unit and the center of gravity determined by the load determination unit differ by more than the predetermined deviation. N can be a predetermined number. Alternatively, the error detection unit can detect an error and / or a potential error if the center of gravity predicted by the calculation unit and the center of gravity determined by the load determination unit exceed a predetermined deviation in at least one of the iterations.Consequently, in this embodiment, an error is detected as soon as the error detection unit first determines that the center of gravity predicted by the calculation unit and the center of gravity determined by the load determination unit differ by more than the predetermined deviation. A third aspect of the present disclosure provides a system that is identical or similar in many aspects to the system according to the second aspect. The difference between the two systems is that the system according to the third aspect uses the speed or acceleration of the load center of gravity instead of the position of the load center of gravity. When the patient support surface is adjusted, the calculation unit can predict the speed or acceleration of the load center of gravity as the at least one second variable.The load determination unit can determine at least the speed or acceleration of the load center of gravity after the adjustment of the patient support surface as the at least one first variable based on the sensor values. The error detection unit can compare the speed or acceleration of the load center of gravity predicted by the calculation unit with the speed or acceleration of the load center of gravity determined by the load determination unit and detect an error and / or a potential error if the deviation exceeds the predetermined value. According to a fourth aspect of the present disclosure, the load determination unit can determine the load and / or the center of gravity of the load based on the sensor values. The load and / or the center of gravity of the load determined by the load determination unit are the first variables. The calculation unit can calculate theoretical sensor values ​​that serve as the second variables.The theoretical sensor values ​​can, for example, be calculated from one or more of the following parameters: the load, the coordinates of the load center of gravity, the sensor values, and / or one or more distances between the load sensors. The theoretical sensor values ​​are the sensor values ​​that the load sensors should output at the load and / or the determined load center of gravity determined by the load determination unit. The error detection unit can compare the sensor values ​​output by the load sensors with the theoretical sensor values ​​calculated by the calculation unit. If the deviation between the sensor values ​​output by the load sensors and the theoretical sensor values ​​calculated by the calculation unit exceeds the specified value, the error detection unit can detect an error and / or a potential error.The error can in particular be an error in at least one of the load sensors. The error detection unit is advantageously able to detect an error and / or a possible error even when the patient support surface is not adjusted, i.e. when the patient support surface is in a static state. In order to determine the load and the load center of gravity, a certain number of load sensors are required. If the load and the load center of gravity are only determined in one direction, for example the x-direction, two load sensors are required. If measurements are taken in two directions, the x- and y-directions, three load sensors are required for static determinacy. In one embodiment, the load sensor arrangement can have at least one more load sensor than is required for static determinacy.If two load sensors are sufficient for static determinacy, the load sensor arrangement can have at least three load sensors. If three load sensors are required for static determinacy, the load sensor arrangement can have at least four load sensors. The at least one additional load sensor allows for a certain degree of redundancy. Mathematically speaking, there are infinitely many combinations of the three or four forces measured by the load sensors that result in exactly the same load and the same load center. But according to the rules for solving statically equilibrated systems, there is only one correct combination of the three or four measured forces that results in a specific load and a specific load center. If one of the load sensors is damaged, it is statistically impossible for this load sensor to randomly assume the correct value that produces a balanced system.The system equilibrium can therefore be characterized by comparing the measured values ​​of the three or four load sensors with the theoretical values ​​that the load sensors should measure for the determined load center of gravity and the load. If the imbalance is above a certain threshold, at least one of the load sensors is not functioning properly. In some embodiments, the multiple load sensors can be arranged in a single common plane. In some embodiments, the load sensors can be arranged symmetrically. In one embodiment, the load sensors of the load sensor arrangement can be arranged parallel and mirror-imaged to one another. For example, the load sensor arrangement can have a total of four force sensors or load cells. This embodiment has the advantage of increased accuracy and reliability.Several or all of the load sensors of the load sensor array can be arranged mirror-symmetrically with respect to a first imaginary axis and mirror-symmetrically with respect to a second imaginary axis. The first and second axes can be aligned orthogonally to each other. For example, the first axis can run parallel to a main axis of the patient support surface, while the second axis can run perpendicular to this main axis but parallel to the patient support surface. The load sensor array can be arranged between the patient support surface and the operating table column. In some configurations, the load sensors are arranged in a grid pattern with a plurality of load sensors on each "side." In some embodiments, all load sensors are arranged in a common plane. For example, the load sensors can be arranged in a 2 x 2 grid.The load sensors can, for example, be arranged in a grid arrangement with 2 to 4 load sensors in each dimension. The mirror-symmetrically arranged load sensors can be aligned in the same direction. In particular, the mirror-symmetrically arranged load sensors can be aligned parallel to one another. The load sensors can each have a main axis, wherein the main axes are aligned parallel to one another. The load sensors of the load sensor arrangement can be identical in construction. In some embodiments, the load sensors have an elongated shape. For example, the load sensors can be rectangular bodies. According to a fifth aspect of the present disclosure, the error detection unit can detect a possible error in at least one of the load sensors if the load determined by the load determination unit is negative. If all load sensors are functioning correctly, the measured load and thus the measured weight should be positive.However, if the measured load is negative, the operating table either collides with an obstacle or the load sensors are malfunctioning. A negative force threshold can be used to determine whether the load sensors are functioning properly. According to a sixth aspect of the present disclosure, the fault detection unit can detect a fault and / or a potential fault of at least one of the load sensors if the load determined by the load determination unit exceeds a predetermined value and / or the load center of gravity determined by the load determination unit lies outside a predetermined space. The operating table is intended for operation under specific conditions. Therefore, unusual load values, e.g., a load value of 1000 kg, indicate that the load sensors are malfunctioning. The same applies to the determined load center of gravity.If the x-, y-, or z-component of the center of gravity is exceptionally high, e.g., an x-coordinate of the center of gravity has a value of 5.32 m, this is an indication that the load sensors are not functioning reliably. Threshold values ​​can be set in the error detection unit to check whether the measured load and the load center of gravity are plausible. According to a seventh aspect of the present disclosure, the error detection unit can detect an error and / or a potential error of one of the load sensors if the load sensor does not change its sensor value while the other load sensors change their sensor values, or if the load sensor changes its sensor value while the other load sensors do not change their sensor values. The load sensors generally detect even the smallest change in the load. In the vast majority of cases in which a load or center of gravity change occurs, e.g.,caused by a longitudinal movement of the patient, all load sensors change their values. If one of the load sensors does not change its value, this indicates that the load sensor is defective. The opposite also applies. If only one of the load sensors changes its value and the values ​​of all other load sensors remain unchanged, this is an indication that the one load sensor that changes its value is defective. According to an eighth aspect of the present disclosure, the error detection unit can detect an error and / or a potential error of one of the load sensors if the load F determined by the load determination unit. gemessen if the patient support surface is tilted and / or tilted, the following equation (1) does not follow: (1) where F Last is a load acting on the patient support surface, α is the angle of inclination and / or cant of the patient support surface and F dlis a tared load that includes all loads belonging to the operating table and located above the load sensors. The tilt and / or cant angle α is the angle defined by the weight force vectors F Last and the measured force F gemessen The force F gemessenruns perpendicular to the main surface of the patient support surface. Equation (1) is only valid if the force sensors are tilted or canted together with the patient support surface. If the force sensors are attached, for example, to the foot of the operating table, equation (1) does not apply. If the patient support surface is tilted in any direction, the measured weight appears lower to the load sensors because the gravity vector is no longer perpendicular to the load sensors. Consequently, the fault detection unit can detect a malfunction of the load sensors if the patient support surface is tilted in any direction and the load F determined by the load determination unit gemessendoes not correspond to equation (1). As already described above, adjusting the patient support surface may include one or more of the following operations: tilting the patient support surface, edging the patient support surface, longitudinally translating the patient support surface, vertically translating the patient support surface, and laterally translating the patient support surface. The error detection unit can detect not only a fault in the load sensors, but also faults and / or potential faults in other sensors used in the operating table.In some embodiments, the fault detection unit can detect a sensor fault in one or more of the following sensors: load sensors, sensors for detecting the inclination of the patient support surface, sensors for detecting the tilt of the patient support surface, sensors for detecting the longitudinal displacement of the patient support surface, sensors for detecting the lateral displacement of the patient support surface, and column stroke sensors. In not all systems, the fault detection unit can detect faults in the column stroke sensors that measure a vertical displacement of the patient support surface. In some systems, the column stroke sensors can be used to determine the tilt and / or tilt angles. An incorrect tilt and / or tilt angle could indicate that at least one of the column stroke sensors may be faulty.If the error detection unit detects an error, the error detection unit can generate an error signal indicating that the operating table is in a safety-critical state. Furthermore, an acoustic and / or visual warning signal can be generated. In addition, a warning signal in text form can be generated, which can be displayed to the user, for example, on a remote control of the operating table. Furthermore, the movement of the operating table can be restricted. For example, the extension and / or tilting and / or edging of the patient support surface and / or the movement of the operating table can be slowed down or stopped. Furthermore, at least one functionality of the operating table can be blocked. The measures taken can be reduced or canceled when the error detection unit determines that the operating table is in a safe state again.According to a ninth aspect of the present disclosure, a method is provided for detecting a sensor error in an operating table and / or an error in determining a load or a load center of gravity. The operating table comprises an adjustable patient support surface for supporting a patient and a load sensor arrangement with a plurality of load sensors that output sensor values. Based on the sensor values, at least one of the following first variables can be determined: a load, a center of gravity of the load, a velocity of the load center of gravity, and an acceleration of the load center of gravity. The load can be a load acting on the load sensor arrangement or a load acting on the operating table or a total load of the operating table. Based on the at least one first variable, at least one expected second variable can be calculated.The sensor values ​​or at least one first variable can be compared with the at least one expected second variable. If the deviation of the sensor values ​​or the at least one first variable from the at least one expected second variable exceeds a predetermined value, an error can be detected. The method according to the ninth aspect can have all the configurations described in the present disclosure in connection with the system according to the first to eighth aspects. The present disclosure also includes circuits and / or electronic instructions for controlling operating tables as well as remote controls, displays and user interfaces for use with operating tables. Brief Description of the Drawings Exemplary embodiments of the present disclosure are explained in more detail below with reference to the figures. Therein: Fig.1 shows a schematic side view of an operating table with a patient positioned on a patient support surface of the operating table; Fig. 2 shows a schematic representation of the system architecture of an operating table system according to the disclosure, with a load sensor arrangement, a load determination unit, a calculation unit, and an error detection unit; Fig. 3 shows a schematic representation of an operating table according to the disclosure, illustrating the measured load, the effective load, and the total load; Figs. 4A to 4C show schematic representations of various embodiments of an operating table according to the disclosure, with a load sensor arrangement in various positions; Figs. 5A to 5D show schematic representations of various embodiments of an operating table according to the disclosure, with force sensors arranged parallel and mirror-symmetrically; Figs. 6A and 6B show schematic representations illustrating the forces acting on the force sensors; Fig.7A and 7B are schematic representations illustrating the reduction of transverse forces due to the symmetrical arrangement of the force sensors; Fig. 8 is a schematic representation illustrating the determination of the gravitational vector with an inclined patient support surface; Fig. 9 is a schematic representation of an operating table system according to the disclosure with an iterative operating method for detecting an error; Figs. 10A and 10B are schematic representations of an operating table according to the disclosure illustrating the movement of the load center of gravity when the patient support surface is inclined; Fig. 11 is a schematic representation of an iterative method for detecting an error using a Kalman filter; Fig. 12 is a schematic representation of the system model of the Kalman filter; Fig. 13 is schematic representations of a tilt rotation and a tilt rotation; Fig.14 shows a schematic representation of an operating table system according to the disclosure with a method for detecting an error using the system imbalance; Fig. 15 shows a schematic representation of the functioning of the operating table system from Fig. 14; and Figs. 16a and 16b show schematic representations of various simulated system imbalances. Detailed Description of the Figures In the following description, exemplary embodiments of the present disclosure are described with reference to the drawings. The drawings are not necessarily to scale, but are intended merely to schematically illustrate the respective features. It should be noted that the features and components described below can each be combined with one another, regardless of whether they have been described in connection with a single embodiment.The combination of features in the respective embodiments serves merely to illustrate the basic structure and mode of operation of the claimed device. In the figures, identical or similar elements are provided with identical reference numerals where appropriate. Fig. 1 schematically shows a mobile operating table 10 which can be used to support a patient 12 during a surgical procedure and to transport the patient. The mobile operating table 10 comprises, from bottom to top, a base 14 for placing the operating table 10 on a surface, a vertically arranged operating table column 16 surrounding the base 14, and a patient support surface 18 fastened to an upper end of the operating table column 16. The patient support surface 18 can be firmly connected to the operating table column 16 or, alternatively, can be detachably fastened to the operating table column 16.The patient support surface 18 is modular and serves to support the patient 12. The patient support surface 18 comprises a main support surface section 20 connected to the operating table column 16, which can be expanded as required by coupling various secondary support surface sections. In Fig. 1, a leg section 22, a shoulder section 24, and a head section 26 are coupled to the main support surface section 10 as secondary support surface sections. The patient support surface 18 of the operating table 10 can be adjusted to a suitable height and can be tilted or canted depending on the type of surgical procedure to be performed. The operating table column 16 is height-adjustable and has an internal mechanism for adjusting the height of the patient support surface 18 of the operating table 10. The mechanism is arranged in a housing 28, which protects the components from contamination.The base 14 has two sections 30, 32 of different lengths. Section 30 is a short section that is assigned to a foot end of the leg section 22, i.e. the end of the patient support surface 18 on which the feet of the patient 12 to be treated rest. Section 32 is a long section that is assigned to the head section 26 of the patient support surface 18. Furthermore, the base 14 can have wheels or rollers with which the operating table 10 can be moved on the floor. Alternatively, the base 14 can be firmly anchored to the floor. For better illustration, a Cartesian coordinate system XYZ is shown in Fig. 1. The X-axis and the Y-axis are the horizontal axes, the Z-axis is the vertical axis. The X-axis extends along the adjacent storage surface sections 22, 24, 26. Fig. 2 schematically shows the system architecture of an operating table system 100 according to the disclosure.The operating table system 100 is a system according to the first aspect of the present disclosure and can be operated using a method according to the ninth aspect. In addition to an operating table 10 as shown in Fig. 1, the operating table system 100 includes a load sensor arrangement 102, a load determination unit 104, a safety unit 106, a monitoring and calibration unit 108, a data memory 110, and other components 112 of the operating table system 100. Furthermore, the safety unit 106 includes a tipping prevention unit 114 and an overload protection unit 116. The monitoring and calibration unit 108 includes a calculation unit 117 and an error detection unit 118. The load sensor arrangement 102 includes a plurality of load sensors and is designed to measure at least one variable from which a load acting on the load sensor arrangement 102 can be determined.In the present case, the load sensors are force sensors, each measuring a force acting on the respective sensor. The sensor or force values ​​measured by the individual force sensors are output by the load sensor arrangement 102 as a signal 120 in digital form. Furthermore, the load sensor arrangement 102 contains electronic components required to operate the force sensors. The load determination unit 104 receives the signal 120 with the measured sensor or force values ​​and determines at least one first variable therefrom, wherein the first variables can be the following: a load, a center of gravity of the load, a speed of the center of gravity of the load, and / or an acceleration of the center of gravity of the load. The load determination unit 104 can determine a measured load, an effective load, and / or a total load as the load.In order to adequately process and analyze the supplied force values, the load determination unit 104 requires some data on the geometry and the masses or weights of the operating table 10 and the accessories. This data is stored in the data memory 110 and is made available to the load determination unit 104 by means of a signal 122. In particular, information on the masses and centers of gravity of the individual components of the operating table 10 and the accessories can be extracted from this data. The data memory 110 can be expanded via a connectivity module of the operating table 10. The load determination unit 104 generates a signal 124 as an output signal, which contains information about the at least one first variable, i.e., the determined loads and / or load centers of gravity, as well as, if applicable, speeds and / or accelerations of the load centers of gravity.Furthermore, the signal 124 contains the sensor values ​​output by the load sensors. This information is transmitted to both the safety unit 106 and the monitoring and calibration unit 108. In the safety unit 106, all available data is analyzed, including the loads, centers of gravity, and position data of the operating table 10 and the accessories detected by the operating table 10. The safety unit 106 decides whether the operating table 10 is safe or whether it is in a dangerous situation. The safety unit 106 generates a safety signal 126 that indicates whether the operating table 10 is in a safety-critical state. Depending on the severity of the detected situation, the algorithm reacts accordingly. For example, the operating table 10 can only issue a warning or stop movement.The warnings can be issued via an acoustic or visual signal by the operating table 10 or in text form via the remote control. The measures can vary from slowing the movement speed to stopping the movement to blocking certain functionalities and can last until a state is reached in which the operating table 10 is safe again. It can be provided that the safety functions can be deactivated by the user at any time and that movement of the operating table 10 can be continued at their own risk. The anti-tip unit 114 and the overload protection unit 116 are subunits of the safety unit 106. The anti-tip unit 114 generates a tipping safety signal 128 based on the total load and / or the center of gravity of the total load, which indicates whether there is a risk of the operating table 10 tipping over.The overload protection unit 116 generates an overload protection signal 130 based on the active load and / or the center of gravity of the active load, which indicates whether there is an overload risk for the operating table 10 and / or at least one component of the operating table 10. Alternatively, the overload protection unit 116 can use the measured load or the total load and / or the center of gravity of one of these loads to generate the overload protection signal 130. Both the anti-tip signal 128 and the overload protection signal 130 are safety signals of the safety unit 106. If the base 14 does not have wheels or casters and is instead firmly connected to the floor, the anti-tip unit 114 can be deactivated or not implemented in the safety unit 106. Since the system 100 is intended to reliably detect critical situations, the system 100 also has a monitoring and calibration unit 108.This software module checks the plausibility of the measured values ​​and detects whether the system is operating incorrectly or whether calibration or taring of the system 100 is necessary. The monitoring and calibration unit 108 generates corresponding output signals 132, 134, which are transmitted to the load determination unit 104 or the components 112 of the operating table 10. The calculation unit 117 integrated into the monitoring and calibration unit 108 receives the signal 124 from the load determination unit 104, which contains information about the at least one first variable, i.e., the determined loads and / or load centers and, if applicable, speeds and / or accelerations of the load centers. The calculation unit 117 calculates at least one expected second variable based on the at least one first variable.The error detection unit 118 compares the values ​​determined by the load sensor arrangement 102 or the load determination unit 104 and the expected second variable determined by the calculation unit 117. The error detection unit 118 compares the sensor values ​​output by the load sensors or the at least one first variable with the at least one expected second variable. If the deviation of the at least one expected second variable from the sensor values ​​or the at least one first variable exceeds a predetermined value, the error detection unit 117 determines that an error is present. The error can, for example, be a faulty sensor or an error that occurs when determining the load or the load center of gravity. The error detection unit 118 generates an error signal 138, which is transmitted to the safety unit 106.The detected errors and the error signal 138 can be interpreted as possible errors or contain a possible error. In some embodiments, it can be provided that further investigations are necessary until it can be determined that an error actually exists. If the error detection unit 118 has detected an error and / or a possible error, the safety unit 106 is informed of this by means of the error signal 138. The safety unit 106 can then take the necessary measures. As described above, for example, a warning can be issued or the movement of the operating table 10 can be slowed down or stopped. The components 112 of the operating table 10 continuously generate position data, data for setting individual components, and information about the accessories detected by the operating table 10. This data is made available to the system 100 with a signal 136.Fig. 3 schematically illustrates the various loads that the load determination unit 104 can determine based on the data received from the load sensor unit 102. In Fig. 3, the measured load, the effective load, and the total load are designated by reference numerals 140, 142, and 144, respectively. For each of these loads, the load determination unit 104 can determine the position of the associated load center of gravity as well as the speed and / or acceleration of the load center of gravity. The measured load is the load acting on the load sensor arrangement 102. The measured load corresponds to the load generated by all persons, objects, and forces on the operating table 10 above the load sensors. The measured load corresponds to the load value measured by the load sensor arrangement 102.The effective load corresponds to the load caused by components not assigned to the operating table 10, as well as people and external forces, and acting on the operating table 10. The influence of the components assigned to the operating table 10 and recognized accessories is not taken into account in the effective load. Only the remaining components of the operating table 10 contribute to the effective load, i.e., the components not assigned to the operating table 10. These can be, for example, accessories that are not recognized by the operating table 10. Furthermore, the patient on the operating table 10 contributes to the effective load. All external forces acting on the operating table 10, which are exerted on the operating table 10, for example, by people and / or objects outside the operating table 10, also contribute to the effective load.The effective load is essentially the measurement load without the influence of known objects such as tabletop parts, detected accessories, etc. The total load is the load resulting from the measurement load and from a load caused by components assigned to the operating table 10 and located below the load sensor arrangement 102. The total load therefore takes into account loads from components located below the load sensor arrangement 102 that cannot be measured by the load sensor arrangement 102 and therefore do not contribute to the measurement load. The total load is therefore the load resulting from the entire operating table 10, the patient, the components assigned to the operating table 10, the components not assigned to the operating table 10, and other external forces. Figs. 4A to 4C schematically show the operating table 10 according to the disclosure in various embodiments.In the operating table 10, the load sensor arrangement 102 with the plurality of load sensors is arranged between at least two parts of the operating table 10. The at least two parts can, in particular, be essentially immobile relative to one another. In this embodiment, the at least two parts essentially do not move relative to one another, i.e., they remain essentially in the same position relative to one another when the operating table 10, in particular the patient support surface 18, is adjusted during operation, e.g., when tilting and / or edging and / or extending the patient support surface 18. This applies both to the distance between the at least two parts and to the angle(s) that the at least two parts form with one another. The load sensor arrangement 102 is preferably integrated into the operating table 10 such that the entire load above the load sensors flows or is transmitted through the load sensor arrangement 102.The load sensor arrangement 102 can be arranged at different positions in the operating table 10. In the embodiment shown in Fig. 4A, the load sensor arrangement 102 is arranged between the base 14 and the operating table column 16, while in Fig. 4B the load sensor arrangement 102 is integrated into the operating table column 16. In Fig. 4C, the load sensor arrangement 102 is located adjacent to the interface between the patient support surface 18 and the operating table column 16. Fig. 5A shows the operating table 10 with a load sensor arrangement 102 arranged between the patient support surface 18 and the operating table column 16. The load sensor arrangement 102 contains four identical force sensors 1a, 1b, 2a and 2b, which are arranged parallel and mirror-symmetrically to one another. Two different variants for the placement of the force sensors 1a, 1b, 2a, 2b are illustrated in Fig. 5B and 5C. Fig.5B and 5C each show a plan view of the load sensor arrangement 102 along a line AA, which is shown in Fig. 5A. In some embodiments, the load sensor arrangement 102 can contain at least three or at least four force sensors. For the alignment of the force sensors 1a, 1b, 2a, 2c, a first axis 210 and a second axis 212 are predetermined, which are perpendicular to one another. The first axis 210 extends parallel to a main axis of the patient support surface 18, while the second axis 212 runs perpendicular to this main axis, but parallel to the patient support surface 18. The force sensors 1a, 1b, 2a, 2c each have a main axis, which in Fig. 5B is aligned parallel to the first axis 210. In Fig. 5C, the main axes of the force sensors 1a, 1b, 2a, 2b are aligned parallel to the second axis 212. Furthermore, the force sensors 1a, 1b, 2a, 2b are arranged in pairs mirror-symmetrically to the axes 210, 212.The pairs (1a, 1b), (1a, 2a), (1b, 2b) and (2a, 2b) each form a mirror-symmetric force sensor pair. In some embodiments, the force sensors 1a, 1b, 2a, 2b are arranged in a 2 x 2 grid as shown. In some embodiments, the grid arrangement has at least two force sensors 1a, 1b, 2a, 2b on each side. In some embodiments, the force sensors 1a, 1b, 2a, 2b all lie in a single common plane that is intersected by both the first axis 210 and the second axis 212. The force sensors can also be arranged within the sensor arrangement 102 differently than in Fig. 5B and 5C. Several exemplary alternative arrangements of the force sensors in the sensor arrangement 102 are shown in Fig. 5D. Using the example of the sensor arrangement 102 shown in Fig.5B or 5C, the measured load can be calculated by adding all forces measured by the sensors 1a, 1b, 2a, 2b.The corresponding center of gravity can be calculated using the torque balance equation below and the forces shown in Figs. 6A and 6B. Fig. 6A shows a cross-sectional view along the x-axis, and Fig. 6B shows a cross-sectional view along the y-axis. The torque balance equation can be applied in both directions, allowing the x- and y-components of the center of gravity to be determined: (2) (3) (4). In equations (2) to (4), FLa is the weight force generated by the patient. The forces F1a, F1b, F2a, and F2b are the forces measured by sensors 1a, 1b, 2a, and 2b, respectively. The parameters a and b are the distances between the sensors in the x and y directions, respectively. X CG and Y CGare the x- and y-coordinates of the center of gravity of the load caused by the patient. The effective load and the total load, as well as their corresponding center of gravity values, can be calculated by adding or subtracting the corresponding components of the operating table 10 and their center of gravity values, which are stored in the data memory 110. The arrangement of the sensors 1a, 1b, 2a, 2b suggested in Figs. 5B and 5C makes the system robust against transverse forces F r Due to the symmetrical arrangement, transverse forces F rcanceled, as shown in Figs. 7A and 7B. The cancellation of the transverse forces also allows the described system to reliably measure forces and center of gravity when the patient support surface 18 is in an inclined position. Fig. 8 shows how the gravitational vector FLast can be split into two components. One component is located lateral to the force sensors and is canceled due to the effects explained above. The second component F gemessenruns perpendicular to the force sensors or to the main surface of the patient support surface 18 and is reliably measured. Knowing the angle of inclination α of the patient support surface 18, the actual load above the sensors and their center of gravity can be calculated. Fig. 9 schematically shows an operating table system 200 according to the disclosure, which is largely similar to the operating table system 100 schematically shown in Fig. 2. Elements of the operating table system 200 that are identical or similar to elements of the operating table system 100 are provided with identical reference numerals. The operating table system 200 is a system according to the second aspect of the present disclosure. In addition to the operating table 10, the operating table system 200 comprises a load sensor arrangement 102 with a plurality of load sensors, a load determination unit 104, a calculation unit 117, an error detection unit 118, and a state estimation unit 119.The state estimation unit 119, together with the calculation unit 117 and the error detection unit 118, can be integrated into the monitoring and calibration unit 108. Before describing the individual components and the functionality of the operating table system 200, the physical and mathematical considerations underlying the operating table system 200 will first be explained. When the patient or the workload of the operating table 10 is moved while the patient support surface 18 is tilted or tilted, the center of gravity of the workload moves along a predictable circular trajectory. When the patient support surface is moved longitudinally, the workload moves along a linear trajectory. Therefore, it is possible to make an estimate of the entire trajectory of the workload when adjusting or moving the patient support surface.This consideration helps to use the position sensors of the operating table 10 to check the load center of gravity determined by the load sensors (and vice versa). If a sensor has an error, the trajectory determined for the workload will not behave as expected. The expected trajectory can be calculated using the kinematics of the operating table 10 and physical relationships known from classical mechanics. This principle is illustrated using Figs. 10A and 10B. Fig. 10A shows the operating table 10 with the patient support surface 18 in a horizontal position. The patient's center of gravity is shown in Fig. 10A and identified by the reference symbol COG. The patient support surface 18 is now tilted, causing the patient's center of gravity to move along a circular trajectory. The patient's center of gravity after adjustment of the patient support surface 18 is shown in Fig.10B through COG. danach The focus COG danach can be determined using the sensor values ​​of the load sensors. Furthermore, the patient's center of gravity, which is reached due to an inclination of the patient support surface 18, can be predicted, forecast, precalculated, or estimated. The predicted center of gravity is shown in Fig. 10B as COG. vorhergesagt If the deviation of the center of gravity COG danach from the predicted center of gravity COG vorhergesagtis too large, it can be concluded that an error has occurred. The detected error may be caused by a defective sensor. The defective sensor may, for example, be a load sensor, a sensor for detecting the inclination of the patient support surface, a sensor for detecting the tilt of the patient support surface, a sensor for detecting the longitudinal displacement of the patient support surface, or a sensor for detecting the lateral displacement of the patient support surface. However, the error may also have occurred during the determination of the load or the load center of gravity. The mathematical steps used by the operating table system 200 to detect an error are explained below. The input values ​​are the load center of gravity, iea point with x, y, and z coordinates in meters, as well as the position of the joints for the inclination and tilt of the patient support surface 18 in degrees, and the longitudinal displacement of the patient support surface 18 in meters. The speed of the load center of gravity, which is determined by a longitudinal and / or la-. teral displacement of the patient support surface 18 can be determined by deriving the longitudinal displacement and the lateral displacement be determined according to time: The speed of the load center of gravity, which is determined by tilting and / or canting the patient support surface 18 can be determined by the rotational speed: where are the rotational speeds of the load center of gravity during the inclination or tilting of the patient support surface 18. is the distance between the measured load center of gravity and the rotation axis of the tilting / tilting joints. The total speed of the load center of gravity is composed of the speeds together and can be determined with the following sum: The above equations allow to predict the estimated load center of gravity iteratively. If the velocity of the center of gravity X CG is known, the estimated position X CG+ of the center of gravity after a short period of time T. In order to detect an error, the operating table system 200 uses an iterative method, which is illustrated in Fig. 11. In this case, a current actual load center of gravity at time t. As explained below, the load center of the load calculated by the state estimation unit 119 in the previous The calculation unit 117 predicts the actual load center based on the actual load center at time t the load center at time t+1 before. At time t+1, sensor values ​​from the load sensors are recorded and the load determination unit 104 uses the sensor values ​​to determine the load center of gravity at time t+1. The state estimation unit 119 then carries out Then, it performs a correction step using a Kalman filter. The state estimation unit 119 estimates the load center predicted by the calculation unit 117 at time t+1 and the load center of gravity determined by the load determination unit 104 at time t+1 the actual load center at time t+1. The Kalman filter therefore uses the values . The use of both information sources – prediction and measurement – ​​leads to a more reliable state estimate. Subsequently, another iteration cycle is performed, in which the actual load center at time t+1. The calculation unit 117 predicts, based on the actual load center at time t+1 the load center of gravity at time t+2. In addition, the load determination unit 104 determines the load center of gravity based on the sensor values ​​of the load sensors recorded at time t+2. at time t+2. Using the Kalman filter, the state estimation unit 119 estimates the load center predicted by the calculation unit 117 at time t+2 and the load center of gravity determined by the load determination unit 104 at time t+2 the actual load center of gravity at time t+2. The procedure is continued accordingly. In the monitoring algorithm described above, the Kalman filter is used to iteratively determine the position estimate of the load center of gravity in a similar manner. If a measurement of the current position deviates too significantly from the prediction over a certain period of time, there may be an error in the sensors or in the determination of the load or the load center of gravity, because the center of gravity is not behaving plausibly. The error detection unit 118 can, in each iteration cycle, change the load center of gravity predicted by the calculation unit 117. with the load center determined by the load determination unit 104. If the deviation If the distance between the two load centers is too large and, for example, exceeds a specified value or distance, the error detection unit 118 can detect an error and / or a potential error. Since the load can reversibly deform the operating table in some positions, the tolerances for detecting an error should be large enough to avoid false positive results. Therefore, a tolerance range should be defined that distinguishes between a true error, such as a sensor error, and sensor noise or inaccuracies in the system model.The Kalman filter can be simplified according to the third aspect of the present disclosure by comparing the velocity or acceleration of the load center of gravity calculated from the kinematics of the operating table 10 with the velocity or acceleration of the load center of gravity derived from the center of gravity measurement, instead of estimating the position of the load center of gravity. If the velocities or accelerations differ too greatly, an error occurs. To illustrate the operation of the Kalman filter, an example algorithm that can be executed by the Kalman filter is given below. For the sake of simplicity, it is assumed that the tilt and tilt rotation axes have the same origin. The distance between the rotation axis of tilt and tilt and the measured center of gravity (X. CG ) is given as distance (radius of the circular path). The speed v CGof the center of gravity can be determined as follows: (8) where: (9) For the Kalman filter, a linear, time-invariant system model is assumed, as shown in Fig. 12. The Kalman filter is described by the following equations: Prediction: (10) Filtering: (11) Reinforcement: (12) can be considered as a unit or identity matrix be accepted. : System state after applying the new observation / measurement New observation / measurement at time k : Kalman gain matrix for projecting the residuals onto the correction of the system state : Transition matrix for passing the system state to the next time point : Covariance matrix of the errors of x k : Process noise to introduce uncertainties due to modeling errors or changing boundaries : Observation matrix for projecting the system states onto the observation / measurement Covariance of measurement noise A 3DOF Kalman filter with a constant velocity can be assumed as follows. This specific filter is based on a linear system with a constant velocity: (13) The process noise matrix is ​​based on white noise: (14) The output matrix H is preconfigured as an identity matrix. Therefore, the filter expects the entire state vector as measurements (x, y, z, vx, vy, vz). If the center of gravity's position, rather than its velocity, is considered, the algorithm can be simplified as shown below. It assumes the following: - tilt as the only source of rotation around the y-axis, - tilt as the only source of rotation around the x-axis, and - longitudinal displacement only contributes to the linear velocity in the x-direction. The calculation of the center of gravity's velocity can be simplified as follows: (15) r tilt and r trendmust be differentiated because they do not have the same rotation axis source, as shown in Fig. 13. Fig. 14 schematically shows an operating table system 300 according to the disclosure, which is largely similar to the operating table system 100 schematically shown in Fig. 2. Elements of the operating table system 300 that are identical or similar to elements of the operating table system 100 are provided with identical reference numerals. The operating table system 300 is a system according to the fourth aspect of the present disclosure. The operating table system 300 comprises, in addition to the operating table 10, a load sensor arrangement 102 with a plurality of load sensors, a load determination unit 104, a calculation unit 117 and an error detection unit 118. The functionality of the operating table system 300 is illustrated in Fig. 15.The load sensor arrangement 102 of the operating table system 300 has four load sensors 1a, 1b, 2a, 2b arranged at the corners of a virtual rectangle 150, shown in Fig. 15. The rectangle 150 has side lengths a and b. The load sensors 1a and 2a, as well as the load sensors 1b and 2b, are each spaced a apart. The load sensors 1a and 1b, as well as the load sensors 2a and 2b, are each spaced b apart. The load sensors 1a, 1b, 2a, 2b measure the force acting on them and output sensor values ​​F. 1a_m , F 1b_m , F 2a_m or F 2b_m which represent the forces acting on the load sensors 1a, 1b, 2a, 2b. The load determination unit 104 determines the force F based on the sensor values. 1a_m , F 1b_m , F 2a_m , F 2b_m the load F ga and the load center with the coordinates X a and Y ain the plane of the rectangle 150. The calculation unit 117 uses the values ​​determined by the load determination unit 104, ie the load F ga and the coordinates X a and Y a of the load center, and calculates theoretical sensor values ​​F based on these values 1a_t , F 1b_t , F 2a_t , F 2b_t . The theoretical sensor values ​​F 1a_t , F 1b_t , F 2a_t , F 2b_t are those sensor values ​​which the load sensors 1a, 1b, 2a, 2b at the load F determined by the load determination unit 104 ga and the load center with the coordinates X a and Y a The error detection unit 118 compares the sensor values ​​F output by the load sensors 1a, 1b, 2a, 2b 1a_m , F 1b_m , F 2a_m , F 2b_m with the theoretical sensor values ​​F calculated by the calculation unit 117 1a_t , F 1b_t , F 2a_t , F 2b_tFor example, the error detection unit 118 can determine the difference F for each of the load sensors 1a, 1b, 2a, 2b i_t – F i_m (with i = 1a, 1b, 2a, 2b). The difference F i_t – F i_m indicates the system imbalance. For example, if one or more of the differences F i_t – F i_m exceed a predetermined value, the error detection unit 118 detects an error and / or a potential error. In some embodiments, the difference F i_t – F i_m be equal in magnitude for all load sensors 1a, 1b, 2a, 2b. In particular, it is sufficient to calculate the difference F i_t – F i_m for only one of the load sensors 1a, 1b, 2a, 2b, since this can already identify a possible fault. An example is the simulated system imbalance F 1a_t – F 1a_min Fig. 16a and 16b for sensor 1a plotted against time. The patient support surface 18 is in a flat position. Curve 160 in Fig. 16a and curve 170 in Fig. 16b indicate the system imbalance of sensor 1a when the operating table system 300 is functioning properly. All other curves show the system imbalance. F1a_t – F 1a_mof the sensor 1a in the case of an artificially induced error in the sensor 1a. In Fig. 16a, the curves 161, 162, 163, 164 show the system imbalance for an artificially induced error of -1000 N, -400 N, 400 N, and 1000 N, respectively. In Fig. 16b, the curves 171, 172, 173, 174 show the system imbalance for a factor of 1.4, 1.2, 0.8, and 0.6, respectively. The respective factor indicates the error factor by which the actual value is multiplied and erroneously displayed by the load sensor 1a. The following is an example of how the load F determined by the load determination unit 104 ga_m and the load center with the coordinates X a_m and Y a_m the theoretical sensor values ​​F 1a_t , F 1b_t , F 2a_t , F 2b_t be calculated, which the load sensors 1a, 1b, 2a, 2b at the load F ga_m and the load center with the coordinates X a_m and Y a_m should spend. For the load Fga_m and the coordinates X a_m and Y a_m of the load center, the relationships described above in equations (2) to (4) apply: (16) (17) (18) The theoretical sensor values ​​F1a_t, F1b_t, F2a_t, F2b_t are calculated from the coordinates Xa_m and Ya_m of the load center and the sensor values ​​F1a_m, F1b_m, F2a_m, F2b_m as follows: (19) (20) (21) (22) The difference between the theoretical sensor values ​​F 1a_t , F 1b_t , F 2a_t , F 2b_t and the respective measured sensor value F 1a_m , F 1b_m , F 2a_m , F 2b_m is identical for all load sensors 1a, 1b, 2a, 2b. This difference Δ can be determined, for example, for load sensor 1a as follows: (23) If the difference Δ is greater than a specified threshold, e.g., 300 N, an error is detected, meaning there is a system imbalance. If the difference Δ is smaller than the threshold, the system is functioning correctly. The following are example values ​​for a system imbalance. For this purpose, load sensor 1a was subjected to an error of 500 N. Measured sensor values: F 1a_m = 3178 NF 2a_m = −1853 NF 1b_m = 3099 NF 2b_m = −2238 N Calculated load and calculated load center: F ga_m = 223 kg X a_m = −58 cm Y a_m = 3 cm Calculated theoretical sensor values: F 1a_t = 3670 NF 2a_t = −2344 NF 1b_t = 2607 NF 2b_t = −1747 N Calculated difference Δ: ∆(F 1a ) = 491 N ∆(F 2a ) = −491 N ∆ ( F 1b ) = −491 N ∆ ( F 2b )= 491 N Since the difference Δ is greater than a specified threshold value of, for example, 300 N, a system imbalance exists, ie, the system is not operating properly. For comparison, exemplary values ​​for a fault-free system are given below. In contrast to the faulty system above, the sensor value F 1a_m no error of 500 N is added. The remaining sensor values ​​F 1b_m , F 2a_m , F 2b_m correspond to the above sensor values. Measured sensor values: F 1a_m = 2678 NF 2a_m = −1853 NF 1b_m = 3099 NF 2b_m = −2238 N Calculated load and calculated load center: F ga_m = 172 kg X a_m = −71 cm Y a_m = 0 cm Calculated theoretical sensor values: F 1a_t = 2830 NF 2a_t = −2005 NF 1b_t = 2947 NF 2b_t = −2086 N Calculated difference Δ: ∆ ( F 1a ) = 152 N ∆(F 2a) = −152 N ∆(F 1b ) = −152 N ∆ ( F 2b )= 152 N The difference Δ is smaller in magnitude than the threshold value of 300 N. Accordingly, the system operates error-free. Exemplary embodiments and variants in accordance with the present disclosure are described in the following list of points and options: Point 1: System (100, 200, 300) for detecting a sensor error in an operating table (10) and / or an error in determining a load or a load center of gravity, comprising: an operating table (10) with an adjustable patient support surface (18) for supporting a patient; a load sensor arrangement (102) with a plurality of load sensors (1a, 1b, 2a, 2b) that output sensor values; a load determination unit (104) that determines at least one of the following first variables based on the sensor values: a load, a center of gravity of the load, a speed of the load center of gravity, and an acceleration of the load center of gravity,wherein the load is a load acting on the load sensor arrangement (102) or a load acting on the operating table (10), or a total load of the operating table (10); a calculation unit (117) that predicts or calculates at least one expected second variable; and an error detection unit (118) that compares the sensor values ​​or the at least first variable with the at least one expected second variable and, if the deviation exceeds a predetermined value, detects an error and / or a possible error. Item 2: System (100, 200) according to item 1, wherein, when the patient support surface (18) is adjusted, the calculation unit (117) predicts the load center of gravity changed by the adjustment as the at least one second variable; the load determination unit (104) uses the sensor values ​​to determine at least the load center of gravity after the adjustment of the patient support surface (18) as the at least one first variable.and the error detection unit (118) compares the load center of gravity predicted by the calculation unit (117) with the load center of gravity determined by the load determination unit (104) and, if the deviation exceeds the predetermined value, detects an error and / or a potential error. Item 3: The system (100, 200) according to item 2, further comprising a state estimation unit (119) which estimates an actual load center of gravity based on the load center of gravity predicted by the calculation unit (117) and the load center of gravity determined by the load determination unit (104), wherein the state estimation unit (119) estimates the actual load center of gravity in particular based on a weighted value of the load center of gravity predicted by the calculation unit (117) and a weighted value of the load center of gravity determined by the load determination unit (104). Point 4: System (100, 200) according to point 3,wherein the state estimation unit (119) has a Kalman filter for estimating the actual load center of gravity. Item 5: System (100, 200) according to item 1, wherein the calculation unit (117), the load determination unit (104), and a state estimation unit (119) operate iteratively, in that the calculation unit (117) predicts the load center of gravity at time t+1 as the at least one second variable based on an actual load center of gravity at time t estimated by the state estimation unit (119), the load determination unit (104) determines the load center of gravity at time t+1 as the at least one first variable, and the state estimation unit (119) subsequently estimates the actual load center of gravity at time t+1 based on the load center of gravity at time t+1 predicted by the calculation unit (117) and the load center of gravity at time t+1 determined by the load determination unit (104). Point 6: System (100, 200) according to point 5,wherein the error detection unit (119) detects an error and / or a potential error if the load center predicted by the calculation unit (117) and the load center determined by the load determination unit (104) each exceed a predetermined deviation in at least a predetermined number of iterations. Item 7: The system (100, 200) according to item 5, wherein the error detection unit (119) detects an error and / or a potential error if the load center predicted by the calculation unit (117) and the load center determined by the load determination unit (104) each exceed a predetermined deviation in at least one of the iterations. Item 8: System (100, 200) according to item 1, wherein the calculation unit (117), when the patient support surface (18) is adjusted, predicts the speed or acceleration of the load center of gravity as the at least one second value,the load determination unit (104) uses the sensor values ​​to determine at least the speed or acceleration of the load center of gravity after the adjustment of the patient support surface (18) as the at least one first variable, and the error detection unit (118) compares the speed or acceleration of the load center of gravity predicted by the calculation unit (117) with the speed or acceleration of the load center of gravity determined by the load determination unit (104) and, if the deviation exceeds the predetermined value, detects an error and / or a potential error. Item 9: System (100, 200) according to item 8, further comprising a state estimation unit (119),which estimates an actual speed or acceleration of the load center of gravity based on the speed or acceleration of the load center of gravity predicted by the calculation unit (117) and the speed or acceleration of the load center of gravity determined by the load determination unit (104). Item 10: System (100, 200) according to item 9, wherein the state estimation unit (119) has a Kalman filter for estimating the actual speed or acceleration of the load center of gravity. Item 11: System (100, 200) according to item 1, wherein the calculation unit (117), the load determination unit (104), and a state estimation unit (119) operate iteratively, in that the calculation unit (117) predicts the speed or acceleration of the load center of gravity at time t+1 as the at least one second variable based on an actual speed or acceleration of the load center of gravity at time t estimated by the state estimation unit (119).the load determination unit (104) determines the speed or acceleration of the load center at time t+1 as the at least one first variable, and the state estimation unit (119) subsequently estimates the actual speed or acceleration of the load center at time t+1 based on the speed or acceleration of the load center at time t+1 predicted by the calculation unit (117) and the speed or acceleration of the load center at time t+1 determined by the load determination unit (104). Item 12: System (100, 200) according to item 11, wherein the error detection unit (118) detects an error and / or a potential error,if the speed or acceleration of the load center of gravity predicted by the calculation unit (117) and the speed or acceleration of the load center of gravity determined by the load determination unit (104) each exceed a predetermined deviation in at least a predetermined number of iterations. Item 13: System (100, 200) according to item 11, wherein the error detection unit detects an error and / or a potential error if the speed or acceleration of the load center of gravity predicted by the calculation unit (117) and the speed or acceleration of the load center of gravity determined by the load determination unit (104) exceed a predetermined deviation in at least one of the iterations. Item 14: System (100, 300) according to item 1, wherein the load determination unit (104) determines the load and / or the load center of gravity as the first variables based on the sensor values,the calculation unit (117) calculates theoretical sensor values ​​as the second quantities, wherein the theoretical sensor values ​​are those sensor values ​​that the load sensors (1a, 1b, 2a, 2b) should output at the load and / or load center determined by the load determination unit (104), and the error detection unit (118) compares the sensor values ​​output by the load sensors (1a, 1b, 2a, 2b) with the theoretical sensor values ​​calculated by the calculation unit (117) and, if the deviation exceeds the predetermined value, detects an error and / or a potential error. Item 15: The system (100, 300) according to item 14, wherein the error detection unit (118) is capable of detecting an error and / or a potential error when the patient support surface (18) is not adjusted. Point 16: System (100, 300) according to one of the previous points,wherein the load sensor arrangement (102) comprises at least three load sensors or at least four load sensors (1a, 1b, 2a, 2b). Item 17: System (100, 300) according to one of the preceding items, wherein the plurality of load sensors (1a, 1b, 2a, 2b) are arranged in a single common plane. Item 18: System (100, 300) according to one of the preceding items, wherein several of the load sensors (1a, 1b, 2a, 2b) are arranged mirror-symmetrically with respect to a first axis (210) and mirror-symmetrically with respect to a second axis (212), and wherein the first and second axes (210, 212) are aligned orthogonally to one another. Item 19: System (100) according to one of the preceding items, wherein the error detection unit (118) detects a possible error in at least one of the load sensors (1a, 1b, 2a, 2b) if the load determined by the load determination unit (104) is negative. Item 20: System (100) according to one of the preceding items,wherein the error detection unit (118) detects an error and / or a possible error of at least one of the load sensors (1a, 1b, 2a, 2b) if the load determined by the load determination unit (104) exceeds a predetermined value and / or the load center of gravity determined by the load determination unit (104) lies outside a predetermined space. Item 21: System (100) according to one of the preceding items, wherein the error detection unit (118) detects an error and / or a possible error of one of the load sensors (1a, 1b, 2a, 2b) if the load sensor does not change its sensor value while the other load sensors change their sensor values, or if the load sensor changes its sensor value while the other load sensors do not change their sensor values. Item 22: System (100) according to one of the preceding items, wherein the error detection unit (118) detects an error and / or a possible error of one of the load sensors (1a, 1b, 2a,2b) detects if the load F determined by the load determination unit (104), gemessen in the case of an inclination and / or tilting of the patient support surface (18), the following equation does not follow: F gemessen = F Last ∙ cos α − (1 − cos α) ∙ F dl , where F Last is a load acting on the patient support surface (18), α is the angle of inclination and / or canting of the patient support surface (18) and F dla tared load comprising all loads belonging to the operating table (10) and located above the load sensors (1a, 1b, 2a, 2b). Item 23: System (100) according to any one of the preceding items, wherein adjusting the patient support surface (18) comprises one or more of the following operations: tilting the patient support surface (18), edging the patient support surface (18), longitudinally displacing the patient support surface (18), vertically displacing the patient support surface (18), and laterally displacing the patient support surface (18). Item 24: System (100) according to one of the preceding items, wherein a sensor error is an error of one or more of the following sensors: load sensors (1a, 1b, 2a, 2b), sensors for detecting the inclination of the patient support surface (18), sensors for detecting the tilt of the patient support surface (18), sensors for detecting the longitudinal displacement of the patient support surface (18),Sensors for detecting the lateral displacement of the patient support surface (18) and column stroke sensors. Item 25: System (100) according to one of the preceding items, wherein the error detection unit (118), upon detection of an error and / or a potential error, generates an error signal such that it indicates a safety-critical state of the operating table (10), an acoustic and / or visual warning signal and / or a warning signal in text form is generated, and / or a movement of the operating table (10) is slowed down or stopped, and / or at least one functionality of the operating table (10) is blocked. Item 26: System (100) according to one of the preceding items, wherein the calculation unit (117) predicts the at least one expected second variable. Item 27: Method for detecting a sensor error in an operating table (10) and / or an error in determining a load or a load center of gravity,wherein the operating table (10) has an adjustable patient support surface (18) for supporting a patient and a load sensor arrangement (102) with a plurality of load sensors (1a, 1b, 2a, 2b) that output sensor values; based on the sensor values, at least one of the following first variables is determined: a load, a center of gravity of the load, a speed of the center of gravity of the load, and an acceleration of the center of gravity of the load, wherein the load is a load acting on the load sensor arrangement (102) or a load acting on the operating table (10) or a total load of the operating table (10); at least one expected second variable is predicted or calculated; and the sensor values ​​or the at least one first variable are compared with the at least one expected second variable, and if the deviation exceeds a predetermined value, an error is detected. Item 28: Method according to item 27, wherein when the patient support surface (18) is adjusted,the load center of gravity changed by the adjustment is predicted as the at least one second variable, based on the sensor values, at least the load center of gravity after the adjustment of the patient support surface (18) is determined as the at least one first variable, and the predicted load center of gravity is compared with the determined load center of gravity, and if the deviation exceeds the predetermined value, an error is detected. Item 29: Method according to item 27, wherein the load and / or the load center of gravity are determined as the first variables based on the sensor values, theoretical sensor values ​​are calculated as the second variables, wherein the theoretical sensor values ​​are those sensor values ​​which the load sensors (1a, 1b, 2a, 2b) should output for the determined load and / or the determined load center of gravity, and which are determined by the load sensors (1a, 1b, 2a,2b) are compared with the theoretical sensor values ​​calculated by the calculation unit (117), and if the deviation exceeds the predetermined value, an error is detected. Item 30: System (100) for detecting an error in a sensor in an operating table (10), comprising: an operating table (10) with an adjustable patient support surface (18) for supporting a patient; a load sensor arrangement (102) with a plurality of load sensors (1a, 1b, 2a, 2b) that output sensor values; a load determination unit (104) that determines at least one load based on the sensor values, wherein the load is a load acting on the load sensor arrangement (102), a load acting on the operating table (10), or a total load of the operating table (10); and an error detection unit (118) which detects a possible error of at least one of the load sensors (1a, 1b, 2a, 2b),if the load determined by the load determination unit (104) is negative. Item 31: System (100) for detecting a sensor error in an operating table (10), comprising: an operating table (10) with an adjustable patient support surface (18) for supporting a patient; a load sensor arrangement (102) with a plurality of load sensors (1a, 1b, 2a, 2b) that output sensor values; a load determination unit (104) that determines at least one load and / or a center of gravity of the load based on the sensor values, wherein the load is a load acting on the load sensor arrangement (102) or a load acting on the operating table (10) or a total load of the operating table (10); and an error detection unit (118) that detects an error and / or a possible error of at least one of the load sensors (1a, 1b, 2a, 2b).if the load determined by the load determination unit (104) exceeds a predetermined value and / or the load center of gravity determined by the load determination unit (104) lies outside a predetermined space. Item 32: System (100) for detecting a sensor error in an operating table (10), comprising: an operating table (10) with a patient support surface (18), in particular adjustable, for supporting a patient; a load sensor arrangement (102) with a plurality of load sensors (1a, 1b, 2a, 2b) that output sensor values; and an error detection unit (118) that detects an error and / or a possible error of one of the load sensors (1a, 1b, 2a, 2b) if the load sensor does not change its sensor value while the other load sensors change their sensor values, or if the load sensor changes its sensor value,while the remaining load sensors do not change their sensor values. Item 33: A system (100) for detecting a sensor error in an operating table (10), comprising: an operating table (10) with an adjustable patient support surface (18) for supporting a patient; a load sensor arrangement (102) with a plurality of load sensors (1a, 1b, 2a, 2b) that output sensor values; a load determination unit (104) that determines at least one load based on the sensor values, wherein the load is a load acting on the load sensor arrangement (102) or a load acting on the operating table (10) or a total load of the operating table (10); and an error detection unit (118) that detects an error and / or a possible error of one of the load sensors (1a, 1b, 2a, 2b) if the load F determined by the load determination unit (104) gemessen if the patient support surface (18) is tilted and / or tilted, the following equation does not follow: F gemessen = F g∙ cos α − (1 − cos α) ∙ F dl , where F g is a load acting on the patient support surface (18), α is the angle of inclination and / or cant of the patient support surface (18) and F dl is a tared load comprising all loads belonging to the operating table (10) and located above the load sensors (1a, 1b, 2a, 2b).

Claims

Claims 1. System (100, 200, 300) for detecting a fault in a sensor in an operating table (10) and / or a fault in determining a load or a load center of gravity, comprising: an operating table (10) with an adjustable patient support surface (18) for positioning a patient; a load sensor arrangement (102) with multiple load sensors (1a, 1b, 2a, 2b) that output sensor values; a load determination unit (104) that determines at least one of the following first quantities based on the sensor values: a load, a center of gravity of the load, a velocity of the center of gravity of the load, and an acceleration of the center of gravity of the load, wherein the load is a load acting on the load sensor arrangement (102), a load acting on the operating table (10), or a total load of the operating table (10); a calculation unit (117) that predicts or calculates at least one expected second quantity;and an error detection unit (118) which compares the sensor values ​​or the at least one first quantity with the at least one expected second quantity and, if the deviation exceeds a predetermined value, detects an error and / or a potential error.

2. System (100, 200) according to claim 1, wherein the computation unit (117), when the patient support surface (18) is adjusted, predicts the load center of gravity changed by the adjustment as the at least one second quantity, the load determination unit (104) determines at least the load center of gravity after the adjustment of the patient support surface (18) as the at least one first quantity based on the sensor values, and; The fault detection unit (118) compares the load center of gravity predicted by the computation unit (117) with the load center of gravity determined by the load determination unit (104) and, if the deviation exceeds the predetermined value, detects a fault and / or a potential fault.

3. System (100, 200) according to claim 2, further comprising a state estimation unit (119) which estimates an actual load center of gravity based on the load center of gravity predicted by the computation unit (117) and the load center of gravity determined by the load determination unit (104), wherein the state estimation unit (119) estimates the actual load center of gravity in particular based on a weighted value of the load center of gravity predicted by the computation unit (117) and based on a weighted value of the load center of gravity determined by the load determination unit (104). 4.System (100, 200) according to claim 3, wherein the state estimation unit (119) comprises a Kalman filter for estimating the actual load center of gravity.

5. System (100, 200) according to claim 1, wherein the computation unit (117), the load determination unit (104) and a state estimation unit (119) operate iteratively, in that the computation unit (117) predicts the load center of gravity at time t+1 as the at least one second quantity based on an actual load center of gravity at time t estimated by the state estimation unit (119), the load determination unit (104) determines the load center of gravity at time t+1 as the at least one first quantity, and the state estimation unit (119) subsequently estimates the actual load center of gravity at time t+1 based on the load center of gravity at time t+1 predicted by the computation unit (117) and the load center of gravity at time t+1 determined by the load determination unit (104). 6.System (100, 200) according to claim 5, wherein the fault detection unit (119) detects a fault and / or a potential fault when the calculated value is exceeded.

7. System (100, 200) according to claim 5, wherein the fault detection unit (119) detects a fault and / or a potential fault if the load center of gravity predicted by the calculation unit (117) and the load center of gravity determined by the load determination unit (104) exceed a predetermined deviation in at least one of the iterations. 8.System (100, 200) according to claim 1, wherein the computation unit (117), when the patient support surface (18) is adjusted, predicts the speed or acceleration of the load center of gravity as at least one second quantity, the load determination unit (104), based on the sensor values, determines at least the speed or acceleration of the load center of gravity after the adjustment of the patient support surface (18) as at least one first quantity, and the fault detection unit (118) compares the speed or acceleration of the load center of gravity predicted by the computation unit (117) with the speed or acceleration of the load center of gravity determined by the load determination unit (104) and, if the deviation exceeds the specified value, detects a fault and / or a potential fault. 9.System (100, 200) according to claim 8, further comprising a state estimation unit (119) which estimates an actual speed or acceleration of the load center of gravity based on the speed or acceleration of the load center of gravity predicted by the computation unit (117) and the speed or acceleration of the load center of gravity determined by the load determination unit (104).

10. System (100, 200) according to claim 9, wherein the state estimation unit (119) comprises a Kalman filter for estimating the actual velocity or acceleration of the load's center of gravity.

11. System (100, 200) according to claim 1, wherein the computation unit (117), the load determination unit (104), and a state estimation unit (119) operate iteratively, such that the computation unit (117), based on an actual velocity or acceleration of the load's center of gravity estimated by the state estimation unit (119) at time t, predicts the velocity or acceleration of the load's center of gravity at time t+1 as the at least one second quantity.The load determination unit (104) determines the velocity or acceleration of the load center of gravity at time t+1 as the at least one first quantity, and the state estimation unit (119) subsequently estimates the actual velocity or acceleration of the load center of gravity at time t+1 based on the velocity or acceleration of the load center of gravity predicted by the computation unit (117) at time t+1 and the velocity or acceleration of the load center of gravity determined by the load determination unit (104) at time t+1.

12. System (100, 200) according to claim 11, wherein the fault detection unit (118) detects a fault and / or a potential fault,if the speed or acceleration of the load center of gravity predicted by the calculation unit (117) and the speed or acceleration of the load center of gravity determined by the load determination unit (104) each exceed a predetermined deviation in at least a predetermined number of iterations.

13. System (100, 200) according to claim 11, wherein the fault detection unit detects a fault and / or a potential fault if the speed or acceleration of the load center of gravity predicted by the calculation unit (117) The center of gravity and the speed or acceleration of the center of gravity determined by the load determination unit (104) exceed a predetermined deviation in at least one of the iterations. 14.System (100, 300) according to claim 1, wherein the load determination unit (104) determines the load and / or the load center of gravity as the first quantities based on the sensor values, the calculation unit (117) calculates theoretical sensor values ​​as the second quantities, wherein the theoretical sensor values ​​are those sensor values ​​which the load sensors (1a, 1b, 2a, 2b) should output at the load and / or load center of gravity determined by the load determination unit (104), and the fault detection unit (118) compares the sensor values ​​output by the load sensors (1a, 1b, 2a, 2b) with the theoretical sensor values ​​calculated by the calculation unit (117) and, if the deviation exceeds the specified value, detects a fault and / or a potential fault. 15.System (100, 300) according to claim 14, wherein the fault detection unit (118) is able to detect a fault and / or a potential fault when the patient support surface (18) is not adjusted.

16. System (100, 300) according to any one of the preceding claims, wherein the load sensor arrangement (102) comprises at least three load sensors or at least four load sensors (1a, 1b, 2a, 2b).

17. System (100, 300) according to any one of the preceding claims, wherein the multiple load sensors (1a, 1b, 2a, 2b) are arranged in a single common plane.

18. System (100, 300) according to any one of the preceding claims, wherein multiple load sensors (1a, 1b, 2a, 2b) are arranged symmetrically with respect to a first axis. (210) and are arranged symmetrically with respect to a second axis (212), wherein the first and the second axis (210, 212) are orthogonally aligned to each other.

19. System (100) according to one of the preceding claims, wherein the fault detection unit (118) detects a possible fault of at least one of the load sensors (1a, 1b, 2a, 2b) if the load determined by the load determination unit (104) is negative.

20. System (100) according to any of the preceding claims, wherein the fault detection unit (118) detects a fault and / or a potential fault of at least one of the load sensors (1a, 1b, 2a, 2b) if the load determined by the load determination unit (104) exceeds a predetermined value and / or the load center of gravity determined by the load determination unit (104) lies outside a predetermined space. 21.System (100) according to any one of the preceding claims, wherein the fault detection unit (118) detects a fault and / or a potential fault of one of the load sensors (1a, 1b, 2a, 2b) if the load sensor does not change its sensor value while the other load sensors change their sensor values, or if the load sensor changes its sensor value while the other load sensors do not change their sensor values.

22. System (100) according to any one of the preceding claims, wherein the fault detection unit (118) detects a fault and / or a potential fault of one of the load sensors (1a, 1b, 2a, 2b) if the load F determined by the load determination unit (104) gemessen In the case of an inclination and / or tilting of the patient support surface (18), the following equation does not apply: F gemessen = F Last ∙ cos α − (1 − cos α) ∙ F dl , where F Lasta load acting on the patient support surface (18), α is the inclination and / or tilt angle of the patient support surface (18) and F dla tared load comprising all loads belonging to the operating table (10) and located above the load sensors (1a, 1b, 2a, 2b).

23. System (100) according to any one of the preceding claims, wherein adjusting the patient support surface (18) comprises one or more of the following operations: tilting the patient support surface (18), adjusting the edges of the patient support surface (18), longitudinally displacing the patient support surface (18), vertically displacing the patient support surface (18), and laterally displacing the patient support surface (18). 24.System (100) according to any one of the preceding claims, wherein a sensor fault is a fault of one or more of the following sensors: load sensors (1a, 1b, 2a, 2b), sensors for detecting the inclination of the patient support surface (18), sensors for detecting the tilting of the patient support surface (18), sensors for detecting the longitudinal displacement of the patient support surface (18), sensors for detecting the lateral displacement of the patient support surface (18), and column stroke sensors. 25.System (100) according to any one of the preceding claims, wherein the fault detection unit (118), upon detection of a fault and / or a potential fault, generates a fault signal such that it indicates a safety-critical state of the operating table (10), generates an acoustic and / or visual warning signal and / or a warning signal in text form, and / or slows down or stops the movement of the operating table (10), and / or blocks at least one functionality of the operating table (10).

26. System (100) according to any one of the preceding claims, wherein the computation unit (117) predicts the at least one expected second quantity.

27. Method for detecting a fault in a sensor in an operating table (10) and / or a fault in determining a load or a load center of gravity, wherein the operating table (10) has an adjustable patient support surface (18) for positioning a patient and a load sensor arrangement (102) with multiple load sensors (1a, 1b, 2a, 2b) that output sensor values; based on the sensor values, at least one of the following first quantities is determined: a load, a center of gravity of the load, a velocity of the center of gravity of the load, and an acceleration of the center of gravity of the load, wherein the load is a load acting on the load sensor arrangement (102), a load acting on the operating table (10), or a total load of the operating table (10); at least one expected second quantity is predicted or calculated;and the sensor values ​​or at least one first quantity is compared with at least one expected second quantity and, if the deviation exceeds a predetermined value, an error and / or a potential error is detected.

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