MOTION CONTROL FOR A MEDICAL FACILITY

Description

[0001] The invention relates to a motion control system for a medical system, specifically for a movable component of the medical system. The invention determines a positional distance between two position sensors of the component and derives a manual operating force from this positional distance.

[0002] Medical systems such as medical imaging systems, radiography, computed tomography, magnetic resonance imaging, ultrasound, or similar, or systems for medical treatment such as radiation therapy or intervention, often contain movable components that are moved during a medical workflow. For example, before image data is acquired using X-ray technology, the radiation source, the X-ray detector, and the patient or the body region to be examined must be positioned relative to one another. This can be done by moving the patient couch on which the patient is placed for the examination, the radiation source, and / or the detector individually. An adjustment movement can be carried out purely manually, i.e. by an operator, with motor support, or fully automatically or autonomously. Manual adjustment is particularly cost-effective because drives and guide devices can be eliminated.In addition, a manual adjustment movement offers a particularly natural and intuitive operating experience for the user.

[0003] However, with large and heavy components, manual adjustment force is no longer sufficient to move the component comfortably. It is particularly demanding to move the component from a stationary position. This applies, for example, when entire medical systems, such as a mobile C-arm system, need to be moved. This is especially true for a patient couch. Depending on the patient's weight, the total manually manageable mass, which is in the range of 100 kg - 200 kg, is easily exceeded.

[0004] High-quality and usually expensive guide systems can now reduce high operating forces.

[0005] Alternatively, control elements equipped with force sensors can be integrated into the movable component. A sensor signal corresponding to a detected operating force is used to control an active, motorized drive. This results in the loss of natural operating feel, as the main load for component movement is provided by the motorized drive. Furthermore, the control element, including the force sensor, is fixed in place. An adjustment movement can only be initiated by touching this control element.

[0006] The publication DE 10 2007 032 533 A1 describes a method and a corresponding device for preventing collisions between parts of a medical diagnostic and / or therapeutic device and external objects. The method involves evaluating data from a distance and / or proximity sensor to distinguish between actual collisions and intentional approaches of the device parts. Information about the device geometry, the sensor mounting location, and real-time position data is used. Calibration data can be used to determine expected sensor values ​​during movement and compare them with the current values. If a threshold is exceeded, the device's movements are restricted or stopped, or a warning signal is issued. The device itself comprises a movable component carrier, a system control unit, distance / proximity sensors, control means, and evaluation means.The evaluation devices analyze the sensor values ​​to determine whether the device is moving, and the control devices use this information to further control the component carrier. Various device designs are possible, including those with multi-axis articulated-arm robots. A sensor collision computer can be integrated into the component carrier control unit to enable rapid response to collision situations. A higher-level collision computer can be present if multiple device parts and sensors are involved. Storage devices can be used to store pre-calculated or measured data and improve the evaluation process.

[0007] In contrast, the object of the present invention is to provide alternative means that allow user-friendly, cost-effective, and flexible motion control for a medical system or one of its components. This object is achieved by a method and a corresponding system for controlling the movement of a component of a medical system, as well as a corresponding medical system, according to the independent claims. Preferred and / or alternative, advantageous embodiments are the subject of the dependent claims.

[0008] The inventive solution to the problem is described below with reference to the claimed method and with reference to the claimed devices. Features, advantages, or alternative embodiments mentioned here are also applicable to the other claimed subject matter, and vice versa. In other words, claims (directed, for example, to a method) can also be developed with features described or claimed in connection with one of the devices. The corresponding functional features of the method are implemented by corresponding modules or units.

[0009] In a first aspect, the present invention relates to a method for controlling a movement of a component of a medical system, wherein the component is movable and the movable component is designed as an elastic, reversibly deformable element, and wherein the elastic deformation of the component is caused by or substantially by a manually applied operating force of a user. The method comprises a plurality of steps. In a first step, a first position parameter is detected by means of a first position sensor arranged on the component. In a second step, a second position parameter is detected by means of a second position sensor arranged on the component.In a third step, a positional distance for the position sensors is determined based on the first and second position parameters by means of a control unit, wherein the positional distance is the distance between the two position sensors along a spatial axis. In a further step, a control signal for a drive unit of the component is generated based on the determined positional distance by means of the control unit.

[0010] Accordingly, a second aspect of the present invention is directed to a system for controlling a movement of a component of a medical device. In addition to the movable component, which is designed as an elastic, reversibly deformable element, and wherein the elastic deformation of the component is caused by or substantially by a manually applied operating force of a user, the system comprises a first position sensor arranged on the component, configured to detect a first position parameter, a second position sensor arranged on the component, configured to detect a second position parameter, and a control unit.This is configured to determine a position distance for the position sensors based on the first and the second position parameter, wherein the position distance is the distance between the two position sensors along a spatial axis, and to generate a control signal for a drive unit of the component based on the determined position distance.

[0011] A third aspect of the present invention relates to a medical system. In some embodiments, the medical system itself as a whole forms the movable component. The medical system further comprises a drive unit and a system according to the invention for controlling a movement of the component. In further embodiments of the invention, the drive unit can also be formed as a component of the movable component.

[0012] The medical system can be designed as a medical imaging system but also as a system for medical treatment or intervention. For example, the medical system is a radiography system in which digital X-ray images are increasingly generated using X-rays. However, it can also be a computed tomography system, a magnetic resonance imaging system, or the like. The medical system comprises one, preferably several, movable components. A movable component refers to a unit of the system that can be moved relative to other units of the system or to the system's surroundings. The movable component can be moved manually, with motor support via the drive unit, or fully motorized. In preferred embodiments of the invention, the movement refers to a translation along a spatial axis.However, a movable component can also be translationally adjustable along several spatial axes, so that the overall movement of the component results from the superposition of the individual translations.

[0013] The system according to the invention for controlling a movement is advantageously integrated into the medical system. Alternatively, at least individual units of the system, in particular the control unit or submodules thereof, can be arranged remotely or in a separate location. The system according to the invention can be configured to perform, in particular, the step of determining a positional distance and the step of generating a control signal, but also the entire method according to the invention, for a medical system.

[0014] In embodiments of the invention, a movable component can be designed as a stand, e.g., a grid wall unit or a ceiling mount, or as a patient couch or the couch board arranged on it. Grid wall units and ceiling mounts typically serve to mount and position imaging units such as an X-ray source and / or X-ray detector. The patient couch serves to accommodate, support, and position a patient.

[0015] A drive unit according to the invention is preferably designed as a linear drive. This preferably comprises an electric motor or a rotary servomotor that drives a shaft in rotation, the rotation of which is translated into a linear movement of the component via a corresponding gear. Alternative drive concepts are also conceivable and within the scope of the invention. In some embodiments, the drive unit also comprises an auxiliary drive designed to effect direction-dependent friction compensation.

[0016] The drive unit can be moved as part of the component during an adjustment movement or can be at least partially stationary relative to another unit of the medical system.

[0017] According to the invention, two different and independent position sensors are provided. Each position sensor is designed to detect position information corresponding to its spatial position and, based on the position information, to generate a further processable position parameter, which is transferred to a control unit of the system according to the invention. In this respect, detecting a position parameter also describes detecting by or transmitting the position parameter from a position sensor to the control unit.

[0018] In a preferred embodiment, the position parameters are to be understood as position specifications that are specified with reference to the same coordinate system, e.g., the plant coordinate system. This is typically a three-dimensional coordinate system.

[0019] In a particularly preferred embodiment, the position parameters are one-dimensional.

[0020] The invention assumes that the two position sensors are arranged or integrated on the component at a distance from each other, in particular along a spatial axis, and that the detected position parameters always differ.

[0021] Next, the control unit determines a position distance along a spatial axis. This means that it determines how far apart the two position sensors are from each other. The determined position distance comprises a magnitude of the distance, but its algebraic sign also contains information regarding the relative position of the position sensors to each other and thus also an indication of the direction of the manual operating force. The invention is further based on the assumption that the determined position distance is a variable that depends on a manual operating force applied to the movable component and acting along the spatial axis. In other words, the invention is based on the assumption that the determined position distance changes in the direction of the spatial axis with the operating force of a user. This procedure is based on the movable component being designed as an elastic, i.e. reversibly deformable element, wherein the elastic deformation of the component is achieved by or due to the manual operating force.is essentially caused by the manual operating force applied by the user.

[0022] Based on the position distance thus determined, the invention allows a conclusion to be drawn about the manual operating force acting on the component. Accordingly, in a further step, a control signal for the drive unit is generated based on the determined position distance. In preferred embodiments of the invention, generating the control signal includes assigning an adjustment force corresponding to the manual operating force to the position distance. In other embodiments, the position distance is used directly to generate a control signal corresponding to the associated adjustment force. This intermediate step is omitted in these embodiments.

[0023] In a preferred embodiment, the adjustment forces assigned to the positional distances are specific to the movable component. The invention thus advantageously takes into account the fact that each component can exhibit different elastic deformation behavior. The elastic deformation behavior depends, for example, on the basic shape, the materials used, and / or the size of the movable component. A compact, heavy component, for example, will exhibit greater rigidity than an elongated, thin, or light component.

[0024] The present invention advantageously replaces a force sensor for detecting a manual operating force with respect to its direction and / or magnitude. This eliminates the cost of the force sensor. Furthermore, the invention allows a manual operating force to be applied at any point on the movable component. This corresponds to a procedure also used for a purely manual adjustment movement. Since no force sensor needs to be implemented, the user can now apply the manual operating force at any point on the component and is not limited to the operating element comprising the force sensor.

[0025] In embodiments, the first and second position sensors are arranged on the component such that they have a maximum rest distance from each other along a spatial axis.

[0026] The rest distance describes the distance between both sensors when the component is stationary and no force acts on the component.

[0027] The further the two position sensors are spaced from each other, the more accurately the elastic deformation behavior of the component can be represented using the position distance. In other embodiments, however, an arrangement of the position sensors within the drive train is more suitable. For example, the first position sensor is installed directly in or on the drive, i.e., the drive unit, while the second position sensor is arranged in or on the output, advantageously at a rear part of the output. For example, the second position sensor is then arranged on the output shaft of the drive unit, i.e., in particular, behind a transmission of the drive unit.

[0028] Particularly advantageous are embodiments of the invention in which position sensors that are already installed in the medical system or the movable component are used to detect the position parameters, for example, the position sensors used to ensure first-fault-safe operation of the medical system. This eliminates the need for additional components and additional costs.

[0029] Accordingly, particularly advantageous embodiments of the invention provide for the first position sensor to be designed, for example, as a rotary encoder of the drive unit. The rotary encoder is an integral component of the drive unit and continuously detects the angular position of the motor to ensure correct motor function. Position information can thus be provided in the form of a position parameter based on the angular position and monitoring the motor revolutions.

[0030] The second position sensor, or in alternative embodiments of the invention, both position sensors, can be designed in any other manner known per se. For example, a position sensor can be designed as a laser sensor, inductive sensor, ultrasonic sensor, capacitive sensor, or the like.

[0031] The control unit is configured to determine a position distance based on the position parameters and to generate a control signal for controlling the movement of the component based on the position distance. The position distance is representative of a manual operating force applied to the component. Therefore, the control signal is suitable for controlling the component according to the manual operating force. The control unit comprises an interface for inputting or detecting the position parameters and for outputting the control signal to the drive unit. The interface can preferably be configured as an integral input and output interface.

[0032] In embodiments of the invention, the control unit can be configured as one or more central and / or decentralized computing modules. The computing modules can each have one or more processors. A processor can be configured as a central processing unit (CPU / GPU). The control unit can, in particular, comprise a motor controller of the drive unit. In further embodiments, the motor controller is configured as part of the drive unit. Furthermore, the control unit comprises an evaluation module or evaluation unit, which processes the position parameters and generates a control signal based on the determined position distance.

[0033] In preferred implementations, the control unit is implemented as part or module of a central processing unit of the medical system. In some implementations, the control unit can be configured as a submodule of the central processing unit, or vice versa. Alternatively, the control unit can be implemented as a local or cloud-based processing server. Furthermore, the control unit can comprise one or more virtual machines.

[0034] The interface of the control unit can generally be designed for data exchange between position sensors and the drive unit and the control unit and / or for data exchange between modules of the control unit. The interface can therefore be implemented in the form of one or more individual data interfaces, which may include a hardware and / or software interface, a data bus, e.g., a PCI bus, a USB interface, a FireWire interface, a ZigBee interface, or a Bluetooth interface.

[0035] In particular, the evaluation module and the motor controller are connected to each other via a data bus. The interface can further comprise an interface of a communications network, wherein the communications network can comprise a local area network (LAN), for example, an intranet or a wide area network (WAN). Accordingly, the one or more data interfaces can comprise a LAN interface or a wireless LAN interface (WLAN or Wi-Fi).

[0036] Particularly preferably, the control unit of the system is configured to evaluate position parameters for various spatial axes. Two position parameters are recorded for each of the various spatial axes, positional distances are determined, and control signals for movement control along the multiple spatial axes are generated. Accordingly, in embodiments of the system according to the invention, a pair of first and second position sensors can be provided for each spatial axis. At the same time, the control unit is configured to generate a positional distance for the positional sensor pairs of each spatial axis and a respective control signal for the drive unit of each spatial axis based on the respective positional distance.

[0037] Accordingly, in some embodiments the system comprises at least one drive unit per spatial axis.

[0038] It is particularly advantageous, as it saves components, to use multidimensional position sensors that can provide position parameters along multiple spatial axes. When arranging multidimensional position sensors, a compromise must be found so that the elastic deformation behavior can be represented across the position distances for all spatial axes measured.

[0039] In an advantageous embodiment, the method comprises assigning an adjusting force acting on the component to the determined position distance, wherein the control signal for the drive unit is generated based on the assigned adjusting force.

[0040] This can involve data exchange between the control unit and an internal or external storage unit, in which, for example, adjustment forces are assigned to various positional distances from the movable component in the form of a look-up table, particularly for the evaluation module or the evaluation unit. Alternatively or additionally, the evaluation module can perform an interpolation or extrapolation step based on existing data pairs to derive an associated adjustment force.

[0041] The memory unit can now include an additional look-up table that establishes a relationship between the adjustment force and corresponding control information, based on which the control signal is derived. The control information is available, for example, as a torque, speed, or position specification for the drive unit corresponding to the adjustment force.

[0042] In other embodiments, the storage unit can, for example, use a look-up table to establish a direct connection between the determined position distance and corresponding control information.

[0043] Particularly advantageously, generating the control signal for the drive unit includes determining a torque specification for the drive unit based on the amount of the assigned adjustment force for motor power assistance. Compared to other control information, a torque specification offers the user the advantage of an authentic operating experience. In other words, the value of the torque specification depends on the amount of the positional distance. In further embodiments, the control information can also be in the form of a position and / or speed specification for the drive unit. This can, for example, be determined by the type of component or the type of drive unit.

[0044] Preferably, the determined position distance also includes directional information related to the manual operating force. In this respect, the invention enables not only a torque specification, but also a specification of the direction of movement for the drive unit according to the direction of the manual operating force by means of a control signal. Preferably, in addition to the torque specification, the direction of rotation for the drive unit can also be generated as control information.

[0045] In order to reliably determine the manual operating force based on the position distance, the position sensors must simultaneously detect their position parameters and transmit them to the control unit. Accordingly, embodiments of the invention provide for the detection of the first and second position parameters simultaneously. "Simultaneously," within the meaning of the invention, should be understood as "with the smallest possible time offset."

[0046] For this purpose, both position sensors are preferably connected to the motor controller and read via it. According to the invention, the motor controller is configured such that it transmits the first and second position parameters in one and the same data packet, also called a telegram, via the data bus to the evaluation module of the control unit for further processing. This prevents a time offset from the transmission of multiple data packets consecutively via the data bus.

[0047] In certain situations, a manual operating force may be applied to the component while it is already moving, for example, to initiate a change in direction or an acceleration of movement, wherein the current movement is attributable to a motor force input. Accordingly, in a preferred implementation, the method according to the invention comprises detecting an acceleration parameter of the drive unit simultaneously with detecting the first and second position parameters. Furthermore, the motor force input of the drive unit is determined based on the acceleration parameter, thus correcting the adjustment force.

[0048] In a preferred embodiment, the adjustment force is corrected by subtracting the determined motor force input.

[0049] This approach is based on the assumption that the portion of the adjustment force, i.e. the corrected adjustment force, which is not applied by the drive unit, is solely due to the manual operating force of the user.

[0050] To calculate the motor force input, the acceleration parameter, a variable that can be used to determine a value for the current acceleration of the drive unit, is used to measure the effective acceleration and multiply it by the moving mass of the component. The component mass can be provided to the control unit or evaluation module as a fixed mass parameter, for example, by the storage unit described above.

[0051] The described procedure allows the adjustment force to be better adapted to the actual manual operating force. In this version, the control signal is generated based on the corrected adjustment force.

[0052] In some embodiments, the system according to the invention also includes an acceleration sensor, which is preferably integrated into the drive unit or interacts with it. The acceleration sensor can be designed, for example, as a conventional MEMS sensor, a strain gauge, or a piezoelectric acceleration sensor.

[0053] Advantageously, the acceleration parameter is also recorded simultaneously with the first and second position sensor and transmitted via the motor controller with the same data packet to the evaluation module of the control unit in order to ensure simultaneity.

[0054] Alternative designs, in which the positional distance is directly converted into a control signal corresponding to the associated adjustment force, can also derive a motor-induced position difference based on the motor force input determined as described above and thus correct the positional distance (also by subtraction). The control signal for the drive unit is then generated based on the corrected positional distance.

[0055] As mentioned at the beginning, the position parameters include information regarding the effective direction of the manual operating force, so that based on the determined position distance, the manual operating force can be determined not only in terms of its magnitude but also in terms of its direction (forward or backward along the spatial axis). Essentially, the effective direction is defined by the sign of the determined position distance. In situations in which the magnitude of the adjusting force cannot be reliably determined, generating the control signal for the drive unit can at least include generating a torque specification for the drive unit, in particular the auxiliary drive, for direction-dependent friction compensation based on the sign of the position distance.The drive unit is therefore controlled in such a way that it exerts a motor drive force on the component in the appropriate direction, sufficient to overcome the mass-related static friction. For this purpose, the evaluation module or unit can again access the component's stored mass parameter. Alternatively, the required torque specific to the component's mass can also be stored directly in the memory unit.

[0056] In alternative embodiments, depending on the design of the drive unit, a direction-dependent position or speed specification for the drive unit can also be generated.

[0057] In order to continuously monitor the medical system and check for manual force input, in particularly preferred implementations the method according to the invention is repeated and particularly preferably carried out at time intervals of, for example, 5 ms or 10 ms. Other time intervals are also possible and within the meaning of the invention. The selected time interval can in particular depend on the movable component and, for example, its typical movement behavior. In other words, position and, if applicable, acceleration parameters are regularly retrieved from the corresponding sensors and evaluated by a control unit. In this way, changes in the manual operating force (in terms of magnitude and / or direction) can be registered essentially without any time delay, and adjustments can be made to the motorized movement control or movement regulation.

[0058] Further embodiments of the method according to the invention provide that the determination of the position distance comprises subtracting a predefined offset specific to the movable component of the medical system, representing a non-elastic deformability of the component, if the sign of the position distance changes between two method runs.

[0059] This approach is based on the realization that the movable component is deformed not only elastically but also inelastically when a (manual) force is applied. This inelastic deformation can be due, for example, to component tolerances, bearing play between two interlocking components of the component or the like, in particular to tolerances of the drive unit, so that when force is applied, components of the component can move relative to one another. This inelastic deformation, for example in the form of a change in the length of the component or a change in the position of one of the position sensors in the spatial axis under consideration, always occurs when the direction of movement of the component is changed, i.e. the sign of the position distance changes. It is not due to the manual operating force itself. The non-elastic deformation, in turn, is specific to the structure orthe individual components of the movable components and can be determined experimentally in advance and stored as a fixed length parameter for the evaluation module.

[0060] In this embodiment, the method therefore advantageously includes a step of comparing the sign of the position distance between two process runs. Furthermore, the method in this embodiment also includes monitoring the direction of movement of the drive unit. Sign comparison and monitoring of the direction of movement are preferably carried out for each of the process runs, i.e., continuously. If the sign changes, half of the length parameter is preferably added to or subtracted from one of the position parameters or the position distance when determining the position distance, taking the direction of movement into account. This also allows the actual manual operating force applied to be more accurately represented by the determined position distance.

[0061] The invention further relates to a computer program with program code for carrying out the method according to the invention for controlling a movement of a component of a medical system when the computer program is executed on a computer.

[0062] The invention further relates to a computer-readable data carrier with program code of a computer program for implementing the inventive method for controlling a movement of a component of a medical system when the computer program is executed on a computer. Advantageously, in particular, the determination of the positional distance or the generation of the control signal based on the positional distance can be carried out on a computer, for example, a processing unit of the medical system.

[0063] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings. This description does not limit the invention to these exemplary embodiments. In different figures, identical components are provided with identical reference numerals. The figures are generally not to scale. They show: FIG 1 shows a schematic flow diagram of a method according to the invention in one embodiment, FIG 2 shows a detailed view of a medical system comprising a control system according to the invention in one embodiment, and FIG 3 shows a diagram illustrating a time course of the position distance in connection with the determined adjusting force, a motor acceleration and a movement speed of the component in one embodiment of the invention.

[0064] Figure 1 shows a schematic flow diagram of a method according to the invention in one embodiment. The method serves to control a movement, in particular an adjustment movement, of a component 30 of a medical system 10.

[0065] In a first step, a first position parameter POS1 is detected S11 by means of a first position sensor PS1 arranged on the component 30.

[0066] In a second step, a second position parameter POS2 is detected S12 by means of a second position sensor PS2 arranged on the component.

[0067] Both position parameters POS1 and POS2 are such that their values ​​can be used to determine a position and / or a position relative to a reference coordinate system, preferably the coordinate system of the medical device 10. In the simplest case, the position parameters POS1 and POS2 directly indicate the position of the corresponding position sensor PS1, PS2.

[0068] A further step S21 is directed to determining a positional distance POSA for the position sensors PS1, PS2 based on the first and second position parameters POS1, POS2 by means of a control unit SE. Both position sensors PS1, PS2 are characterized in that they are arranged on the movable component 30, but each at different positions (at least with respect to a spatial axis). The invention assumes that the positional distance POSA between the two position sensors PS1 and PS2 is a variable dependent on a manual operating force acting on the component. In other words, the invention assumes that the movable component is elastically deformable and that the change in the positional distance POSA is based on this elastic deformability.

[0069] Based on the determined position distance POSA, the invention establishes a relationship between the determined position distance POSA and the acting manual operating force in the further course of the method.

[0070] Accordingly, in a further method step S30, a control signal SIG is generated for a drive unit AE of component 30 based on the determined positional distance POSA. This means that a control signal for controlling the movement of component 30 is generated, which corresponds to the manual force applied based on the determined positional distance.

[0071] In some embodiments, step S21 may include, in addition to determining the positional distance POSA, also assigning an adjusting force VK acting on the component to the determined positional distance POSA. The control signal SIG for the drive unit AE is then generated based on the assigned adjusting force VK. In this case, the control unit SE explicitly determines a value for the adjusting force VK, which is used as the basis for generating the control signal SIG in the further course of the method. For this purpose, the control unit SE accesses, for example, an internal memory where specific values ​​for the adjusting force VK are stored for various positional distance values ​​for the movable component 30.Alternatively, the control unit SE can also calculate a value for the adjustment force VK itself using a retrievable calculation rule according to a likewise component-specific, functional relationship between the position distance POSA and the adjustment force VK.

[0072] Both variants for generating the control signal SIG based on the position distance POSA or the adjustment force VK are equivalent. The control signal SIG is designed as a control signal for the drive unit AE. It is designed to effect or trigger motorized motion assistance and / or friction compensation.

[0073] Accordingly, the control signal SIG for the drive unit SE is preferably generated in step S30 by determining a torque specification for the drive unit AE based on the magnitude of the assigned adjusting force VK and / or the determined positional distance POSA for motor power assistance. In contrast, friction compensation can already be performed based on directional information, i.e., the sign, of the positional distance POSA or the adjusting force VK using an auxiliary drive of the drive unit AE. This is particularly advantageous for situations in which the adjusting force VK cannot be precisely determined. In such situations, the drive unit AE can still be used.

[0074] In order to determine the position distance POSA or the adjustment force VK as precisely as possible, steps S11 and S12 for detecting the first and second position parameters POS1, POS2 are preferably performed simultaneously. The smaller the time offset between detecting the two position parameters POS1, POS2, the more accurately the determined position distance POSA represents the currently acting manual operating force. Simultaneity is ensured in embodiments of the invention by retrieving or transmitting the position parameters POS1, POS2, for example, via the motor controller 23 of the drive unit AE, or by transmitting them within the same data packet.

[0075] In an optional step S13 of the method according to the invention, in addition to the position parameters POS1, POS2, an acceleration parameter BES of the drive unit AE is also recorded. The acceleration parameter BES provides information about whether and with what acceleration the movable component 30 is moving. The acceleration parameter BES thus indicates the state of movement of the movable component 30. The acceleration parameter BES is preferably recorded using an acceleration sensor BS arranged on the drive unit AE of the component 30. The acceleration parameter BES thus indicates a portion of the movement of the component 30 attributable to the drive unit AE. Step S13 is also advantageously carried out simultaneously with the recording of the first and second position sensors POS1, POS2.

[0076] Furthermore, in a further optional step S22, a motor force input MOTK of the drive unit AE is determined based on the acceleration parameter BES. For this purpose, the motor force is determined based on the moving mass of component 30, which is known to the system according to the invention, e.g., is stored in memory and can be retrieved, and the acting acceleration. In order to precisely determine the currently acting manual operating force, the motor force input MOTK is used in a likewise optional step S23 to correct the adjusting force VK. The correction is performed by subtracting the motor force input MOTK from the adjusting force VK. During the subtraction, the magnitudes and signs of the calculated forces are taken into account.

[0077] In a further optional step S24, a predefined offset O specific to the movable component 30 of the medical device 10, representing a non-elastic deformability of the component 30, is subtracted when the sign of the position distance PO-SA changes between two process runs. This optional step further improves the determination of the currently applied manual operating force, because the offset allows the invention to further consider non-elastic deformation components of the component 30, which can also be caused by the manual operating force. The offset is available, for example, in a memory unit and can be retrieved as a predefined and experimentally determinable offset value specific to each component. The non-elastic deformation always occurs or can always be observed when the movable component changes its direction of movement.If the movement continues in the same direction, the deformation remains. Therefore, the offset O is always taken into account when determining the adjustment force VK if a change in sign for the position distance POSA was detected in a test loop within step S21. If no change in sign occurs between two process loops, step S24 is not executed. In a preferred embodiment, the offset can be configured as a value representing a change in length of component 30 in a considered spatial axis.

[0078] In a further step S40, the generated control signal SIG is transmitted to the drive unit AE, in particular, for example, via a motor controller 23 of the drive unit AE for execution.

[0079] For continuous motion control, the method according to the invention is repeatedly executed at a time interval Δt. This means that the positions of the position sensors PS1, PS2, the motor acceleration exerted by the drive unit AE, and / or the like are monitored over a period of time, e.g., over the entire operating life of the medical system, and evaluated for motion control. In a preferred embodiment, the position parameters are recorded at a time interval of 3 ms to 15 ms; more preferably, the position parameters POS1, POS2 are recorded at a time interval of 5 ms to 10 ms. These time intervals have been shown in tests to create a particularly intuitive and immediate operating experience for the user.

[0080] Figure 3In this context, a diagram depicts the temporal progression of the positional distance POSA in relation to the continuously determined adjustment force VK. The observation period extends over approximately 5 s. A motor acceleration or the resulting motor force input MOTK, as well as a component-specific offset when reversing the direction of movement, were taken into account. The movement speed of component 30 is also plotted in the diagram. It can be seen that the adjustment force VK follows the progression of the (average) positional distance POSA with a slight offset.

[0081] Figure 2shows a detailed view of a medical system 10 comprising a control system according to the invention in one embodiment. The medical system comprises a movable or movable component 30. In a preferred embodiment, the medical system 10 is designed as a medical imaging system, i.e., it serves to generate medical image data of a patient. Particularly preferably, the medical system 10 is a medical X-ray imaging system that includes an X-ray source and an X-ray detector (not shown). Specifically, the medical system is a radiography system with which conventional X-ray transmission images are generated.In these embodiments, the movable component 30 of the medical system 10 is preferably designed as a floor-mounted or ceiling-suspended stand for supporting an imaging unit such as the X-ray source or the X-ray detector.

[0082] However, the medical system can also be designed differently, for example, as a system for treatment or intervention. In other embodiments of the medical system 10, the movable component 30 can preferably be designed as a patient table, which is designed for supporting or positioning the patient.

[0083] The medical system further comprises a drive unit AE and a system according to the invention for controlling a movement of the component 30.

[0084] The drive unit AE is presently configured as part of component 30. In embodiments of the invention, the drive unit AE is at least partially moved along with the movement of the components. The drive unit AE comprises, as a drive element, an electric motor M configured as a servomotor, which, when operated via a gearing G comprising at least one gear engaging a rack, causes a rotational movement of its drive shaft to translate into a translational movement of the component. In embodiments, the drive unit AE can further comprise an auxiliary drive (not shown), which is used for direction-dependent friction compensation.

[0085] The system for controlling a movement of the component 30 is designed to carry out the steps S11 to S40 of the method according to the invention, in particular also the optional steps, as described with reference to Figure 1described above. The system for controlling a movement of the component 30 comprises a first position sensor PS1 arranged on the component 30. This is configured to detect a first position parameter POS1. It further comprises a second position sensor PS2 arranged on the component, which is configured to detect a second position parameter POS2.

[0086] The first position sensor PS1 is designed here as a position or rotary encoder PS1 of the electric motor M and is therefore installed as standard in medical systems. The second position sensor PS2 is designed here as a position sensor, which is mounted on the output end of the rack.

[0087] In principle, the accuracy in determining the position distance POSA or the adjustment force VK can be increased if the two position sensors have the greatest possible, i.e., maximum, rest distance from each other, i.e., if they are mounted on component 30 as far apart as possible along the considered spatial axis. In this way, the elastic deformation behavior of component 30 can be optimally mapped via the position distance.

[0088] The system also includes an acceleration sensor BS, which is also installed directly on the motor M of the drive unit AE and records an acceleration parameter BES of the motor M.

[0089] The motion control system further comprises a control unit SE. This control unit is configured to determine the position distance POSA for the position sensors PS1, PS2 based on the first and second position parameters POS1, POS2, and to generate a control signal SIG for the drive unit AE, in particular the motor M, based on the determined position distance POSA.

[0090] For this purpose, the control unit SE may comprise an evaluation unit 21. This is designed to carry out all calculation, determination, and ascertainment steps of the method according to the invention in the sense of S21, S22, S23, S24, and S30.

[0091] The control unit SE further comprises a data interface for bidirectional communication between various units of the medical system 10 and the control unit SE.

[0092] The evaluation unit 21 is configured to exchange data via interface 22 for receiving position and acceleration parameters POS1, POS2, BES and for outputting control signals SIG. In particular, the interface 22 can establish a data connection between the evaluation unit and the motor controller 23 of the drive unit AE. According to the invention, the motor controller 23 serves as a central communication or monitoring unit for the drive unit and ensures, for example, a substantially simultaneous transmission of the position parameters POS1, POS2 per process run.

[0093] In addition, the motor controller 23 can also be used to transmit the acceleration parameter BES to the evaluation unit 21 at the same time.

[0094] Not shown here, but within the meaning of the invention, the component 30 of the medical device 10 can be designed to be moved not only along one, but along multiple spatial axes. In this sense, the system for movement control can comprise a pair of first and second position sensors for each spatial axis, wherein the control unit SE is then configured to generate a position distance for the position sensor pairs of each spatial axis and a respective control signal for the drive unit of each spatial axis based on the respective position distance. In other words, the control unit is designed to carry out the method according to the invention with respect to multiple spatial axes, in particular simultaneously or with temporal overlap. The interface 22 is accordingly designed to provide a data exchange between the evaluation unit 21 and a motor controller 23 of the drive units AE provided for the multiple spatial axes / directions of movement.

[0095] The advantages of the invention are briefly summarized below: The invention enables the magnitude and direction of a manual operating force to be recorded without requiring a force sensor in the medical system. The costs for the force sensor can be eliminated. Furthermore, the present invention allows the manual operating force to be applied anywhere in the movable component, thereby increasing the flexibility and intuitiveness of operating the medical system. Operation is no longer limited to the area of ​​the component in which the force sensor is mounted, e.g., an operating handle or lever.

[0096] In embodiments of the invention, the first position parameter is detected using a sensor system that is installed as standard in the drive unit, e.g., the position or rotary encoder of an electric motor. Since a medical system must typically be designed to be first-fault safe and therefore includes, in addition to the actual control path, a protection path for automatically controlling and monitoring the control path, the second position parameter can also be detected using redundant protection path sensors that are installed as standard. This advantageously minimizes additional costs for implementing the motion control system according to the invention.

[0097] Implementing a small auxiliary drive that only compensates for friction to support a largely manual adjustment of the component saves costs compared to servo drives that completely handle the adjustment movement. If the evaluation unit outputs a control signal including a torque specification for the drive unit's motor, i.e., if the motion control system is operated in torque mode, a synthetic operating feeling for the user can be avoided, as would occur, for example, with position or speed control.

[0098] Where not explicitly stated, but appropriate and in accordance with the spirit of the invention, individual embodiments, individual aspects, or features thereof may be combined or interchanged without departing from the scope of the present invention. Advantages of the invention described with reference to one embodiment also apply to other embodiments without explicit mention, where transferable.

Claims

1. Method for controlling a motion of a component (30) of a medical installation (10), wherein the component can be moved and the moveable component (30) is designed as a resilient, reversibly deformable element, wherein the resilient deformation of the component (30) is brought about or is substantially brought about by a manual application of operating force by a user, comprising the steps: - capture (S11) of a first position parameter (POS1) by means of a first position sensor (PS1) arranged on the component, - capture (S12) of a second position parameter (POS2) by means of a second position sensor (PS2) arranged on the component, - determination of a position spacing (POSA) for the position sensors on the basis of the first and the second position parameter by means of a control unit (SE), wherein the position spacing (POSA) is the spacing between the two position sensors (PS1, PS2) along a spatial axis, - generation of a control signal (SIG) for a drive unit (AE) of the component on the basis of the determined position spacing.

2. Method according to claim 1, further comprising - assignment of an adjusting force (VK) acting on the component to the determined position spacing, wherein the generation of the control signal for the drive unit takes place on the basis of the assigned adjusting force.

3. Method according to claim 2, wherein the generation of the control signal for the drive unit comprises ascertaining a torque specification for the drive unit on the basis of the absolute value of the assigned adjusting force for motorised power assistance.

4. Method according to one of claims 1 to 3, wherein the capture of the first and the second position parameter takes place simultaneously.

5. Method according to one of the preceding claims, further comprising: - capture (S13) of an acceleration parameter (BES) of the drive unit simultaneously with the capture of the first and the second position parameter by means of an acceleration sensor (BS), and - determination (S22) of a motorised input of force (MOTK) of the drive unit on the basis of the acceleration parameter, - correction (S23) of the adjusting force on the basis of the motorised input of force.

6. Method according to claim 5, wherein the adjusting force is corrected by subtraction of the motorised input of force.

7. Method according to claim 1, wherein the generation of the control signal for the drive unit comprises generating, on the basis of the sign of the position spacing, a torque specification for the drive unit for direction-dependent friction compensation.

8. Method according to one of the preceding claims, wherein the method is carried out repeatedly with a time interval (Δt).

9. Method according to claim 8, wherein the determination of the position spacing further comprises subtracting a previously defined offset (O) specific to the movable component of the medical installation and representing a non-elastic deformability of the component if the sign of the position spacing changes between two passes of the method.

10. System for controlling a motion of a component (30) of a medical installation (10), comprising: - a moveable component (30) which is designed as a resilient, reversibly deformable element, wherein the resilient deformation of the component (30) is brought about or is substantially brought about by a manual application of operating force by a user, - a first position sensor (PS1) arranged on the component, designed for the capture of a first position parameter (POS1), - a second position sensor (PS2) arranged on the component, designed for the capture of a second position parameter (POS2), - a control unit (SE), designed o for the determination of a position spacing (POSA) for the position sensors on the basis of the first and the second position parameter, wherein the position spacing (POSA) is the spacing between the two position sensors (PS1, PS2) along a spatial axis, and o for the generation of a control signal (SIG) for a drive unit (AE) of the component on the basis of the determined position spacing.

11. System according to claim 10, wherein the first and the second position sensor are arranged on the component such that they have a maximum spacing at rest to one another along a spatial axis.

12. System according to claim 10 or 11, comprising a pair consisting of a first and second position sensor for each spatial axis, wherein the control unit is designed to generate a position spacing for the position sensor pairs of each spatial axis and a respective control signal for the drive unit of each spatial axis on the basis of the respective position spacing.

13. System according to one of claims 10 to 12, wherein in each case the first position sensor is designed as a rotary encoder of the drive unit.

14. Medical installation (10) comprising a drive unit (AE) and a system for controlling a motion of a component according to one of claims 10 to 13.

15. Medical installation according to claim 14, wherein the movable component is designed as a stand to support an imaging unit or as a patient table.