Sensor system for an actuator, actuator and method for moving an actuator part

Abstract

The invention relates to a sensor system (1) for an actuator (50), in particular a lifting column; the invention further relates to a sensor system (1), to an actuator (50) having such a sensor system (1), to a mobile X-ray system (60) having such an actuator (50), and to a method for moving an actuator part (3) of an actuator (50), which is mounted so as to be movable relative to the actuator base (12, 13). The force sensor (2) is provided for detecting a total force (F1) acting on the actuator part (3). An acceleration sensor (4) is provided for detecting an acceleration (a) of the actuator component (3). According to the invention, the sensor system (1) has a processing device (5) which is designed to control a drive (6) of the actuator (50) for moving the actuator component (3) on the basis of the detected total force (Fl) and the detected acceleration (a).

Description

[0001] The present application is a divisional application of the application with the application number 202110235794.X, the application date March 3, 2021, and the title “Sensor system for an actuator, actuator and method for moving an actuator component”. TECHNICAL FIELD

[0002] The present application relates to a sensor system for an actuator, in particular a lifting column, an actuator having such a sensor system, a mobile X-ray system having such an actuator, and a method for moving an actuator component of an actuator, which is movably supported relative to an actuator base. BACKGROUND

[0003] Moving heavy loads generally requires a high expenditure of force by the user. In order to simplify such movements, it is known to use actuators which assist the movement by means of a counterweight or spring system. Such solutions, although reducing the effective load weight which is felt by the user, do not reduce the inertia which arises with the high mass of the load. In order to carry out rapid movements or to accelerate the load, a high expenditure of force is therefore always required.

[0004] This disadvantage can be eliminated by means of a motor-driven actuator. The user can here comfortably move the load by correspondingly operating the motor, for example in such a way that he operates a corresponding key or joystick. Disadvantageously in this case, however, is that the precision of the motor-controlled actuator movement is limited by the speed at which it is to be carried out. SUMMARY

[0005] It is an object of the present application to further improve the actuator assistance when moving a load, in particular to achieve a high precision in the positioning of the load even at high movement speeds.

[0006] The object is achieved by a sensor system for an actuator, in particular a lifting column, an actuator having such a sensor system, a mobile X-ray system having such an actuator, and a method for moving an actuator component of an actuator, which is movably supported relative to an actuator base, according to the independent claims.

[0007] The sensor system for an actuator, in particular a lifting column, according to the first aspect of the application has a force sensor and an acceleration sensor. The force sensor is provided to detect a total force acting on an actuator component which is movably supported relative to an actuator base. The acceleration sensor is provided to detect an acceleration of the actuator component. According to the application, the sensor system further has a processing device which is provided to control a drive device of the actuator for moving the actuator component on the basis of the detected total force and the detected acceleration.

[0008] An actuator part in the sense of the present application is in particular an actuator part which is movably supported relative to an actuator base, that is to say other actuator parts, or which is movable, in particular slidable, relative to an actuator base. Examples of such actuator parts are plungers or pistons which are for example translatable relative to an actuator base configured as a housing, in particular a gas cylinder, by means of an electric motor. Further examples are segments, for example slider-like segments, of a lifting column which are for example able to slide towards a columnar segment of the lifting column configured as an actuator base by means of an operating trolley group.

[0009] The actuator part is preferably provided for carrying a load, for example an X-ray head of an X-ray system.

[0010] A total force in the sense of the present application is in particular the sum of all forces acting on an actuator part during a movement of the actuator part relative to an actuator base. The total force is composed of for example a force applied to the actuator part by a user for the purpose of guiding, of (inertial) forces corresponding to the acceleration produced by this force and of the weight of the actuator part and / or of a load connected thereto in the case of a movement of the actuator part guided by the user. The weight can in particular vary over time in the case of a movement of the actuator part.

[0011] An aspect of the present application is based on the approach of correlating the force acting on a movably relative to a base of an actuator part of an actuator caused by an acceleration with a measured total force acting on the actuator part. The drive means, for example a motor, of the actuator for moving the actuator part can then be controlled on the basis of the measured acceleration and the measured total force.

[0012] Here, a force or at least one measure for this force which is for example actively applied to the actuator part by a user in the case of a guided movement of the movably part is preferably obtained from the acceleration or the (inertial) force corresponding thereto and the total force. The drive means can thus be controlled on the basis of the acceleration and the total force in such a way that the movement of the actuator part guided by the user is assisted. This enables the user to position even heavy loads connected to the actuator part precisely and quickly. The user is enabled to carry out an intuitive movement of such heavy loads. Here, in particular it is not necessary for the user to operate a dedicated control device, for example in the form of a hand grip or a hand rail, in order to cause a movement of the actuator part or to assist a movement of the actuator part guided thereby. The present application thus enables an assistance in the movement of a load without a control device.

[0013] For detecting the acceleration of the actuator component, an acceleration sensor, for example in the form of a microelectromechanical system (MEMS) on an integrated circuit (IC), is preferably provided, and for detecting the total force acting on the actuator component, a force sensor, for example in the form of a load cell, is provided. By means of a processing device, for example implemented by a printed circuit board (PCB) or an application-specific integrated circuit (ASIC) equipped with corresponding data detection and processing electronics, it is possible to determine, for example, the magnitude of the force applied to the actuator component and to generate corresponding control commands for controlling the drive device.

[0014] For example, the processing device can be configured to determine exactly the force applied to the X-ray head by the user in order to guide the movement of the X-ray head, in particular of the X-ray collimator, which is carried by the lifting column and is movably supported by means of the lifting column relative to the lower structure, for example a carriage, and to use this as a basis for controlling the electric drive of the lifting column. The user can accelerate the X-ray head to high speeds without great effort and still position it exactly by hand. Here, it is not necessary to provide a dedicated handle or contact point. Rather, the user can apply the force for the movement to the X-ray head at any point on the X-ray head, this force can be recorded by means of the force sensor and taken into account when controlling the drive.

[0015] The preferred embodiments of the application and the improvements thereof described below can be combined with one another and with the further described aspects of the application, as long as this is not explicitly excluded.

[0016] In a preferred embodiment, the processing device is configured to determine the magnitude of the force applied to the actuator component, in particular by the user in order to move the actuator component, preferably by the action of the user's hand, on the basis of the detected total force and the detected acceleration and to use this as a basis for controlling the drive device. The processing device can in particular be configured to cause the actuator component to track the action of the user's hand by means of the drive device on the basis of the determined magnitude, that is to say to issue instructions to the drive device which cause the actuator component to track the action of the hand. This makes it possible to reliably reduce the burden on the user when moving the actuator component or a load connected thereto.

[0017] In another preferred embodiment, the processing device is configured to control the drive device on the basis of stored calibration values. To this end, the sensor system, in particular the processing device, can have a memory in which the calibration values have been stored or can be stored. The stored calibration values as a basis allow the drive device to be controlled in dependence on the force applied to the actuator component by the user without knowledge of the mass of the actuator component or a load connected thereto.

[0018] In another preferred embodiment, the stored calibration value corresponds to the total force acting on the actuator part when the actuator part is at rest, that is to say when the actuator part is not in operation. The calibration value can in particular correspond to the weight of the actuator part and / or the weight of a load connected thereto. The influence of the weight of the actuator part on the total force detected when the actuator part is in motion can thus be determined and taken into account when controlling the drive device.

[0019] In another preferred embodiment, the force sensor is provided for detecting the total force acting on the actuator part when the actuator part is at rest in the calibration mode. Preferably, the sensor system can be operated in or brought into the calibration mode for this purpose. The processing device is preferably provided in this case for storing the total force detected when the actuator part is at rest as a calibration value. This enables precise detection of the weight of the actuator part or the weight of a load connected thereto.

[0020] Preferably, the sensor system or the actuator is provided in this case for signaling the calibration mode to the user. For example, the processing device can be provided for emitting a corresponding optical or acoustic signal in the calibration mode or for sending an instruction to emit the optical or acoustic signal. This makes it possible to ensure that the user does not exert a force on the actuator part during detection of the calibration value.

[0021] It is also conceivable as an alternative or in addition that the sensor system or the actuator is provided for locking the movement of the actuator part relative to the actuator base in the calibration mode. For example, the processing device can be provided for locking the actuator part in the calibration mode by means of a latching mechanism which is provided for facilitating positioning of the actuator part relative to the actuator base. This makes it possible to prevent the user from moving the actuator part unintentionally during calibration.

[0022] In another preferred embodiment, the processing device is provided for normalizing the total force detected by means of the force sensor using the total force acting on the actuator part when the actuator part is at rest, that is to say when the actuator part is not in operation. The processing device is preferably provided in this case for normalizing the detected total force by means of the stored calibration value. This makes it possible to provide the total force acting on the actuator part at rest quickly and reliably.

[0023] Furthermore, the processing device is preferably provided in this case for deriving the force exerted on the actuator part or at least one dimension of the force from the total force thus normalized. The exerted force or the dimension of the force can accordingly also be derived without knowledge of the mass of the actuator part or the mass of a load connected thereto. This makes it possible, for example, to easily equip an actuator, in particular a lifting column, with a sensor system even after the event.

[0024] In another preferred embodiment, the processing device is configured to control the drive means on the basis of a quotient which is derived from the force which is applied to the effector component, in particular by the user, in order to move the effector component, and the total force which acts when the effector component is at rest. The processing device can be configured in particular to derive the quotient on the basis of the normalized total force, from the total force which is detected by the force sensor when the effector component is moved. This quotient can constitute a measure of the force which is applied to the effector component, for example by the user, in order to move the effector component, in particular by means of the movement of his hand. The drive means can thus quickly and precisely track the movement of the hand of the user.

[0025] In another preferred embodiment, the force sensor is configured as a load cell. Such a load cell can be configured particularly compactly and can thus be easily integrated in the effector, in particular at different locations.

[0026] In another preferred embodiment, the force sensor is configured to detect the total force by detecting the cable tension of a cable which carries the effector component. For this purpose, the force sensor can be connected on one side to the cable and on the opposite side to the effector component. A change in the cable tension from the rest state, for example from a calibration mode, reliably allows a measure of the force which is applied to the effector component by the user to be derived.

[0027] In other words, the processing device can be configured to monitor the deviation of the cable tension from the calibration value and to use the deviation of the cable tension from the calibration value, in particular together with the detected acceleration, as a basis for controlling the drive means. The detection of the cable tension can be realized in a particularly compact manner technically particularly easily.

[0028] In another preferred embodiment, the force sensor is configured to detect the total force by detecting the weight which is applied to a screw which carries the effector component. The force sensor can thus be protected particularly well within the effector, for example within a column element of a lifting column.

[0029] The effector according to the second aspect of the application, in particular a lifting column, has an effector base, an effector component which is movably supported relative to the effector base, a drive means for moving the effector component and a sensor system according to the first aspect of the application. The effector component is preferably configured as a slider which can be moved along a side of the effector base, for example. Furthermore, the effector component is preferably configured to carry a load, such as an X-ray head. The effector component can have fastening means for this purpose, such as threaded holes for threadably connecting a load, a latching mechanism for suspending a load and / or the like.

[0030] ​In a preferred embodiment, the acceleration sensor and the processing device are arranged on and / or in the actuator component. The actuator, in particular the actuator base, can thus be constructed particularly compactly. As an alternative or in addition, a force sensor is also arranged on and / or in the actuator component. This enables a direct and thus error-free detection of the total force acting on the actuator component.

[0031] In another preferred embodiment, the force sensor is arranged in a recess of the actuator component. The force sensor can in particular be accommodated in a recess formed by the side of the actuator component and the actuator base. The force sensor can thus be particularly reliably protected from external influences which can interfere with the detection of the total force.

[0032] The mobile X-ray system according to the third aspect of the application has a walkable lower structure, an actuator according to the second aspect of the application mounted on the walkable lower structure, and an X-ray head mounted on an actuator component movably supported relative to the actuator base.

[0033] In a method for moving an actuator component, in particular a lifting column, of an actuator, the actuator component being movably supported relative to an actuator base, (i) a total force acting on the actuator component and (ii) an acceleration of the actuator component are detected. According to the application, (iii) a drive of the actuator for moving the actuator component is controlled on the basis of the detected total force and the detected acceleration, in particular on the basis of a measure of the force exerted on the actuator component. Here, the measure of the force exerted on the actuator component can be derived on the basis of the detected total force and the detected acceleration.

[0034] The description of preferred embodiments of the application so far contains a large number of features which are shown in various combinations in the individual dependent claims. However, the features can also be considered individually and combined in further suitable combinations. In particular, the features can be combined individually and in any suitable combination with the sensor system according to the first aspect of the application, the actuator according to the second aspect of the application, the X-ray system according to the third aspect of the application and the method according to the fourth aspect of the application.

[0035] The above-mentioned properties, features and advantages of the application and the way in which they are implemented are explained in detail in the following description of embodiments of the application with reference to the accompanying drawings. In the drawings, the same reference signs are always used for the same or corresponding elements of the application. The embodiments serve to illustrate the application and do not restrict the application to the combinations of features listed therein, nor to the functional features. Suitable features of the individual embodiments can also be considered individually and in combination with any of the claims. BRIEF DESCRIPTION OF DRAWINGS

[0036] At least some of the drawings are shown schematically in the drawings:

[0037] Figure 1A is an example of a sensor system for an actuator;

[0038] Figure 1B is a free body diagram shown with forces acting on the load;

[0039] Figure 2 is a sectional view of a first example of an actuator with a sensor system;

[0040] Figure 3 is a sectional view of a second example of an actuator with a sensor system;

[0041] Figure 4 is an example of a mobile X-ray system;

[0042] Figure 5 is an example of a method for moving an actuator component. DETAILED DESCRIPTION DETAILED DESCRIPTION

[0043] Figure 1A An example of a sensor system 1 for an actuator, in particular a lifting column, is shown. The sensor system 1 has a force sensor 2 which is provided for measuring a total force F l acting on an actuator component 3 of the actuator, which is movably supported relative to an actuator base, for example a (not shown) housing, of the actuator. The sensor system 1 also has an acceleration sensor 4 which is provided for detecting an acceleration a acting on the actuator component 3. A processing device 5 of the sensor system 1 is provided for controlling a drive device 6 of the actuator for moving the actuator component 3 on the basis of the detected total force F l and the detected acceleration a.

[0044] In the example shown, the drive device 6 is provided for rotating a nut 9 via a transmission mechanism 11. The nut 9 preferably has an internal thread which engages with an external thread 10a of a screw 10. A rotational movement of a shaft of the drive device 6 can thus be converted into a translational movement of the actuator component 3 by means of the nut 9 and the screw 10.

[0045] The force sensor 2, the acceleration sensor 4 and the drive device 6 are in signal or data connection with the processing device 5, as is shown schematically in Fig. 1. At least a part of the connection, in particular at least a part of the connection between the processing device 5 and the drive device 6, can also be configured here in a wireless manner, for example in order not to impede the movement of the actuator component 3 relative to the drive device 6.

[0046] In order to move the load 25 connected to the actuator part 3, for example via the fastening 7, for example in threaded connection with the threaded hole 7a of the fastening 7, the user can exert a force F on the load 25 and thus also on the actuator part 3 h . This force F exerted, for example, by the user's hand, can be detected by the force sensor 2 as a component of the total force F l . h .

[0047] For this purpose, Figure 1B the force acting on the load with the mass M is shown in the free-body diagram. The total force F l also includes the non-constant (inertial) force F l = M • a, which corresponds to the acceleration a caused by the force exerted on the load 25 or the actuator part 3. As shown in Figure 1A and Figure 1B , this force acts in opposition to the force F h exerted on the load 25. For the total force F l correspondingly results:

[0048] F l = M • a - F h .

[0049] The force F h exerted by the user on the load 25 or the actuator part 3 or at least one dimension of this force can thus be determined by means of the processing device 5 by measuring the acceleration a with the aid of the acceleration sensor 4. It is preferably irrelevant here whether the load 25 is already in motion, for example because the actuator as a whole is moved, for example when the actuator is mounted on a movable platform, such as a slide or a vehicle.

[0050] The dimension of the force F h can serve as a basis for controlling the drive 6. The movement of the load 25 caused by the user can thus be assisted by the drive 6.

[0051] In order to be able to achieve assistance by the drive 6 independently of the mass M of the load 25 to be moved, the processing device 5 preferably takes into account a calibration value when controlling the drive 6, which calibration value is stored, for example, in a memory 8 of the sensor system 1, in particular of the processing device 5.

[0052] The calibration value preferably corresponds to the total force F l0 detected by the force sensor 2 in a calibration mode of the sensor system 1, in which the actuator part 3 is at rest, that is to say not in operation. Since no force F happlied to the load 25 or to the actuator part 3 and which is not an acceleration of the actuator part 3, so that the total force F l0 = M • a0corresponds to the weight force, wherein a0is the acceleration of gravity.

[0053] The processing device 5 is preferably provided to use the total force F l0 measured with the force sensor 2 l is normalized so that as a measure for the force F h applied in the movement of the actuator part 3 the quotient

[0054]

[0055] or

[0056]

[0057] In the case of the measurement of the acceleration a and the total force F l acting on the actuator part 3 the quotient can be calculated quickly, that is to say essentially in real time, using the calibration value F l0 stored in the memory 8 and the acceleration of gravity a0and thus used as a basis for the control of the drive 6 in order to achieve a tracking of the actuator part 3 or of the load 25 connected thereto.

[0058] Figure 2 A sectional view of an example of an actuator 50 with a sensor system 1 is shown. The sensor system 1 has a force sensor 2, an acceleration sensor 4 and a processing device 5. The actuator 50 is in this case configured as a lifting column, which has a first base part 12, a second base part 13 and an actuator part 3. Here, the second base part 13 is configured in a columnar manner and movably, in particular telescopically, supported relative to the likewise columnar configured first base part 12. The actuator part 3 is movably, in particular slidably, supported relative to the columnar configured second base part 13, in particular along a side face 14 of the second base part 13. The actuator 3 can for this purpose be configured as a slide, which moves between two guide rails 23, only one of which can be seen in Figure 2 . The guide rails 23 here extend in the longitudinal direction of the actuator 50, that is to say parallel to the longitudinal axis 22.

[0059] In order to move the parts of the actuator 50 relative to one another, a drive 6 in the form of a motor is provided. This drive 6 is arranged on a first cover plate 18 of the first base part 12, which delimits the upper end of the first base part 12.

[0060] The components of the sensor system 1 are integrated in the shown example in the implement part 3, that is to say are arranged on or in the implement part 3. The force sensor 2 is arranged here for detecting the total force acting on the implement part 3, while the acceleration sensor 4 is arranged for detecting the acceleration of the implement part 3. The processing device 5 can control the drive device 6 on the basis of the detected total force and the detected acceleration in such a way that the movement of the implement part 3 relative to the base parts 12, 13 by the user is assisted.

[0061] The implement part 3 can be connected to the first base part 12 via the block 15 for this purpose. The implement part 3 is carried here by the rope 16 of the block 15, which can be fastened on the externally lying end of the rope 16. The implement part 3 has a recess 20 in the shown example for fastening the rope 16, which can extend partly in the recess. The force sensor 2 is arranged, for example, on the inner end of the recess 20, in particular in connection with the rope 16. The force sensor 2 can therefore detect the total force acting on the implement part 3 by means of the detection of the rope tension of the rope 16.

[0062] The rope 16 is guided via a deflection roller 17 arranged on the second base part 13 and fastened with a base part-side end on the first base part 12, in particular on the first cover plate 18. The block 15 therefore also causes the implement part 3 to move relative to the second base part 13 when the second base part 13 moves relative to the first base part 12.

[0063] In order to move the second base part 13 relative to the first base part 12, the drive device 6 arranged on the first cover plate 18 is coupled, for example via a transmission mechanism, with the nut 9, which can in particular be fastened on the first base part 12 in the region of the first cover plate 18. The inner thread of the nut 9 is engaged here with the outer thread of the screw 10, so that a rotation of the nut 9 driven by the drive device 6 effects a translation of the screw 10. The screw 10 is fastened on the upper end of the second base part 13 facing away from the first base part 12, in particular from the first cover plate 18, in particular on the second cover plate 24 of the second base part 13, so that the second base part 13 is also moved relative to the first base part 12 when the screw 10 is translated. At the same time, a movement of the implement part 3 relative to the second base part 13 is also effected via the block 15.

[0064] In order to be able to support the actuator 50 in the extended state, a weight compensation 19 is preferably provided, which can be configured for example as an air spring. The cylinder 19a of the air spring is connected here to the second base element 13, while the piston 19b of the air spring is connected to the first base element 12. By this means the weight of the load (not shown) connected to the actuator part 13, which also acts via the deflection roller 17 on the second base element 13, can be balanced. This makes it possible to achieve a weight compensation of the second base element 13 and the actuator part 3 or a load coupled thereto, so that for example a smaller drive 6 can be used.

[0065] With Figure 2 Instead of the example shown, the drive 6 can also be arranged on the floor 21 of the first base element 12, which defines the lower end of the first base element 12.

[0066] The nut 9 can be configured here as a sleeve and extends along the longitudinal direction of the actuator 50, that is to say substantially parallel to the longitudinal axis 22, through the entire first base element 12, in order to be able to interact with the screw 10 even in the case of a complete extension of the second base element 13. It goes without saying that it is also possible to interchange the arrangement of the nut 9 and the screw 10, so that the screw 10 is rotated by the drive 6 and the translation of the nut 9 is achieved. The principle of action is not changed thereby.

[0067] Also with Figure 2 Instead of the fastening of the inner end of the rope 16 on the first cover plate 18, it is also possible, instead of the example shown, to provide a further drive with which the actuator part 3 can be moved relative to the first base element 12 independently of the movement of the second base element 13 if necessary.

[0068] Figure 2 The further drive, which is not shown, can be provided for example for driving a rope drum on which the rope 16 can be wound or from which the rope 16 can be unwound. By corresponding control of the further drive it is thus possible to shorten or lengthen the rope 16 and thereby to displace the actuator part 3 along the side face 14.

[0069] Figure 3 A sectional view of a second example of an actuator 50 with a sensor system 1 is shown, in which a load 25 carried by the actuator part 3 is also shown schematically. Not only the actuator 50, but also the sensor system 1, are substantially arranged in the first base element 12. Figure 2The actuator or sensor system shown corresponds to this. Therefore, sensor system 1 also includes a force sensor 2 for detecting the total force acting on actuator component 3 and an acceleration sensor 4 for detecting the acceleration of actuator component 3. Processing device 5 is configured to control drive device 6 based on the detected total force and detected acceleration, thereby enabling the slider-shaped actuator component 3, guided by guide rail 23, to move along the side 14 of the second base member 13. The second base member 13 is also movably, and particularly telescopically, supported relative to the first base member 12.

[0070] As in Figure 2 As shown in the example, force sensor 2 is disposed on or in actuator component 3. However, in principle, it is also possible to dispose of force sensor 2 in other locations, as long as force sensor 2 can detect the total force acting on actuator component 3 there. If the weight balancer 19 is not provided, that is, if the components of the total force are not balanced, then force sensor 2 can be disposed, for example, on the upper end of the second base member 13 opposite to the first base member, particularly on the second endplate 24 of the second base member 13, which defines the upper end of the second base member 13. Force sensor 2 is preferably already connected or will be connected to the second base member 13 on one side and to the screw 10 on the opposite side, which converts the rotation of nut 9 driven by drive device 6 into translation and thereby realizes the movement of the second base member 13 relative to the first base member 12.

[0071] In this Figure 3 In the embodiment not shown, without the weight balancer 19, the force sensor 2 is thus protected within the second base 13 and can detect the total force acting on the actuator component 3 by detecting the gravity of the load 25 pressing on the screw 10. The load 25, for example, an X-ray head, is fastened to the actuator component 3. The gravity of the load 25 is transmitted here to the second base 13 via the guide roller 17 of the trolley block 15, where it can then be detected.

[0072] Figure 4 An example of a mobile X-ray system 60 is shown, which has an actuator 50 configured as a lifting column 50. The actuator has a base 12, an actuator component 3 movably supported relative to the base 12, a drive mechanism 6 for moving the actuator component 3, a sensor system 1 with a force sensor 2, an acceleration sensor 4, and a processing device 5. The X-ray system 60 has a walkable lower structure 61, which in this example is configured as a three- or four-wheeled slide. The X-ray system 60 also has an X-ray head 62 for generating X-rays. This X-ray head 62 is preferably mounted on the actuator component 3 by means of a linear actuator 63 and is therefore capable of being positioned, for example, relative to a patient.

[0073] The force sensor 2 is arranged to detect the total force acting on the X-ray head 62 connected to the effector part 3, for example when the user guides the X-ray head 62 by hand for positioning. The acceleration sensor 4 is arranged to detect the acceleration of the X-ray head 62, for example in such a movement. The processing device 5 is arranged to control the drive means 6 for moving the effector part 3 and thus also the X-ray head 62 relative to the base 12, more precisely on the basis of the detected total force and the detected acceleration. The movement of the X-ray head 62 guided by the user can thus be assisted by the drive means 6. This significantly reduces the force expenditure of the user required for the movement and still allows an intuitive and fast positioning of the X-ray head 62 despite its great weight.

[0074] Figure 5 An example of a method 100 for moving an effector part of an effector relative to a base of the effector is shown.

[0075] In a method step S1, the sensor system is operated in a calibration mode. Here, the total force acting on the effector part is detected when the effector part is at rest, that is to say during a standstill of the effector part or when it is not moved. For this purpose, a force sensor is preferably provided, which can for example be arranged in such a way that it also indirectly supports or carries the effector part if necessary. In the calibration mode, the force sensor thus detects the weight of the effector part or of a load fastened thereto essentially without movement of the effector part.

[0076] Within the scope of the method step S1, the total force detected with the force sensor when the effector part is at rest is preferably stored as a calibration value in a memory. The calibration mode can then be ended.

[0077] In a further method step S2, the total force acting on the effector part is detected when the sensor system is no longer in the calibration mode, that is to say for example when the user moves the effector part. This total force can then consist of a plurality of forces, for example the weight of the effector, the (inertial) force caused by the acceleration and the force exerted on the effector part by the user for the movement. In contrast to the calibration mode, the total force detected by the force sensor when the effector part is moved changes accordingly.

[0078] In a further method step S3, the acceleration of the effector part is detected, which is for example caused by the user by moving the effector part. For this purpose, an acceleration sensor can be provided.

[0079] In another method step S4, a measure for the force applied to the actuator part by the user is determined, more precisely based on the detected total force and the detected acceleration. The detected total force can be normalized here using the stored calibration value. The detected acceleration is preferably also normalized using a normalization value, in particular the gravitational acceleration. The normalization value can also be stored in the memory, that is to say together with the calibration value.

[0080] Preferably, a quotient is determined from the force applied to the actuator part and the calibration value as the measure for the force applied to the actuator part.

[0081] In another method step S5, the drive device is controlled based on the determined measure for the force applied to the actuator part, the drive device being provided for moving the actuator part relative to the base part. The actuator part can thus reliably and precisely track the movement performed by the user.

[0082] List of reference signs

[0083] 1 sensor system

[0084] 2 force sensor

[0085] 3 actuator part

[0086] 4 acceleration sensor

[0087] 5 processing device

[0088] 6 drive device

[0089] 7 fastening mechanism

[0090] 7a threaded hole

[0091] 8 memory

[0092] 9 nut

[0093] 10 screw

[0094] 10a external thread

[0095] 11 transmission mechanism

[0096] 12 first base part

[0097] 13 second base part

[0098] 14 side face

[0099] 15 trolley block

[0100] 16 rope

[0101] 17 deflection roller

[0102] 18 first cover plate

[0103] 19 weight balancing member

[0104] 19a cylinder

[0105] 19b piston

[0106] 20 gap

[0107] 21 base plate

[0108] 22 longitudinal axis

[0109] 23 guide rail

[0110] 24 second cover plate

[0111] 25 load

[0112] 50 actuator

[0113] 60 X-ray system

[0114] 61 lower structure

[0115] 62 X-ray head

[0116] 63 linear actuator

[0117] 100 method

[0118] S1 to S5 method steps

[0119] F l total force

[0120] a acceleration

[0121] F h applied force

[0122] M mass

Claims

1. Sensor system (1) for an actuator (50), in particular a lifting column, having a force sensor (2) and an acceleration sensor (4), the force sensor being arranged to detect a total force (F l ), which acts on an actuator part (3) which is movably supported relative to an actuator base (12, 13), the acceleration sensor being arranged to detect an acceleration (a) of the actuator part (3).​ characterized in that a processing device (5) which is arranged to control a motor drive (6) of the effector (50) for moving the effector part (3) on the basis of the detected total force (F l ) and the detected acceleration (a) in order to assist the movement of the effector part (3) guided by the user, wherein the processing device (5) is arranged for this purpose to derive a measure of the force (F h ) applied by the user to the effector part (3) for moving the effector part (3) on the basis of the detected total force (F l ) and the detected acceleration (a) and to use this as a basis for controlling the drive (6) and to issue instructions to the drive (6) for the effector part (3) to track the movement of the hand of the user.

2. The sensor system (1) as claimed in claim 1, characterized in that: The processing device (5) is designed to assist the movement of the effector part (3) guided by the user without a control device.

3. The sensor system (1) as claimed in claim 1, characterized in that: The processing device (5) is designed to assist the movement of the effector part (3) guided by the user without a control device in the form of a handle or handrail.

4. The sensor system (1) according to any one of the preceding claims, characterized in that: The force sensor (2) is arranged to detect the force (F l ) exerted by the user on a load carried by the effector member (3) for movement, independently of the point on the load at which the force (F l ) is exerted.

5. The sensor system (1) according to any one of the preceding claims, characterized in that: The processing device (5) is designed to control the drive (6) on the basis of stored calibration values.

6. The sensor system (1) as claimed in claim 5, characterized in that: The stored calibration value corresponds to the total force (F l0 ) acting on the actuator member (3) when the actuator member (3) is at rest.

7. A sensor system (1) as claimed in any one of claims 5 or 6, characterized in that: The force sensor (2) is arranged for detecting (S1) in a calibration mode a total force (F l0 ) acting on the actuator member (3) when the actuator member (3) is at rest.

8. The sensor system (1) according to any one of the preceding claims, characterized in that: The processing device (5) is arranged for normalizing the total force (F l0 ) acting on the actuator member (3) when the actuator member (3) is at rest with the total force (F l ) detected by means of the force sensor (2).

9. The sensor system (1) according to any one of the preceding claims, characterized in that: The force sensor (2) is arranged to detect the total force (F l ) by detecting a cable tension of a cable (16) carrying the actuator component (3).

10. The sensor system (1) according to any one of the preceding claims, characterized in that: The force sensor (2) is arranged to detect the total force (F l ) by detecting the weight exerted on a screw (10) carrying the actuator member (3).

11. Effector (50), in particular lifting column, having an effector base (12, 13), an effector part (3) movably supported relative to the effector base (12, 13), a drive (6) for moving the effector part (3), and a sensor system (1) according to one of the preceding claims.

12. The effector (50) of claim 11, characterized by: The acceleration sensor (4) and the processing device (5) are arranged on and / or in the effector part (3).

13. An actuator (50) as claimed in either one of claims 11 or 12, characterized in that: The force sensor (2) is arranged in a recess (20) of the effector part (3).

14. Mobile X-ray system (60) having a walkable lower structure (61), an effector (50) according to one of claims 11 to 13 mounted on the walkable lower structure (61), and an X-ray head (62) mounted on the effector part (3) movably supported relative to the effector base (12, 13).

15. Method (100) for moving an actuator part (3), in particular of a lifting column, of an actuator (50), which is movably supported relative to an actuator base (12, 13), wherein detecting (S2) the total force (F l ) acting on the actuator member (3) and detecting (S3) the acceleration (a) of the actuator member (3), characterized in that based on the detected total force (F l ) and the detected acceleration (a), in order to assist the movement of the actuator part (3) guided by the user, wherein the processing device (5) is provided for this purpose to determine a measure of the force (F h ) applied by the user to the actuator part (3) for moving the actuator part (3) on the basis of the detected total force (F l ) and the detected acceleration (a) and to use this as a basis for controlling the drive (6), and to issue an instruction to the drive (6) to the effect that the actuator part (3) is to follow the movement of the hand of the user.

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