Method for a mobile medical device, computer program, control device and mobile medical device

Abstract

The invention relates to a method for a mobile medical device, a computer program, a control device and a mobile medical device wherein the mobile medical device comprises a differential drive unit for driving a first and a second wheel, the method comprises the following method steps:-determining a first wheel speed of the first wheel and a second wheel speed of the second wheel,-determining a first brake variable of the first wheel and a second brake variable of the second wheel, the brake variables describing the extent to which the respective wheel is decelerated, a smaller brake variable is determined for a wheel having a smaller wheel speed than for a wheel having a higher wheel speed,-applying the first brake variable and the second brake variable to decelerate the first and second wheels.

Description

TECHNICAL FIELD

[0001] The invention relates to the technical field of mobile medical devices, in particular to automatic deceleration of mobile medical devices with differential drive. The technology is applied to a plurality of mobile medical devices, which also include mobile C-arm, mobile head scanner, mobile imaging and / or therapy devices. BACKGROUND

[0002] Automatic deceleration of mobile medical devices with differential drive (in the following also referred to as vehicles) after release of an activation element (for example emergency brake) is a challenge, in particular when driving through a curve. Conventional approaches, in which both drive wheels are decelerated simultaneously and with the maximum allowed deceleration, lead to an unpleasant behavior of the vehicle. As soon as the first wheel stops, the vehicle rotates around this wheel, which is reinforced again by the freely rotating support wheels. This behavior is perceived by the user as uncomfortable and unsafe, in particular in heavy vehicles.

[0003] Mobile medical devices with differential drive usually comprise two driven wheels on an axle and one or two passive, freely rotating support wheels. The drive wheels are individually steered in order to steer the vehicle. The simplest algorithm for decelerating both wheels with the maximum deceleration proves to be insufficient in practice, since it leads to the described spin behavior (Eindrehverhalten).

[0004] The problem has not been solved by the medical vehicles so far, in which the wheels are decelerated with the maximum deceleration independently of each other, which also leads to the spin behavior. SUMMARY

[0005] It is the task of the invention to provide a method, computer program, control device and medical device, which controls the automatic deceleration such that the vehicle stops safely and comfortably even when driving through a curve. Here, the implementation costs of the control software should be kept to a minimum. The solution should minimize or completely avoid the spin behavior independently of the vehicle mass and improve the comfort and safety of the user.

[0006] The subject of the invention is a mobile medical device, a method for decelerating a mobile medical device, a computer program and a control device.

[0007] The method can form a computer-implemented method and / or a method implemented by a control device. The method is used for automatic deceleration of a mobile medical device. In particular, the method is configured to decelerate the mobile medical device when driving through a curve. The mobile medical device preferably comprises a mobile mechanism and at least two driven wheels. In particular, the medical device comprises at least one further wheel, which is preferably not driven. The medical device particularly comprises a functional section, wherein the functional section for example comprises a transmission unit, an imaging unit or a therapy unit. For example, the medical device comprises a C-arm, a vascular imaging device, an X-ray device and / or a head scanner. The mobile medical device particularly has a self-weight of more than 200 kg, in particular more than 500 kg and optionally more than 1000 kg. The method is particularly configured to automatically decelerate the mobile medical device after releasing an activation element, for example an emergency brake element. In other words, the method is preferably applied and / or initiated only when the activation element is released and / or not manipulated any more. In particular, the execution of the method is inhibited when the activation element is activated.

[0008] The mobile medical device has a differential drive unit. The differential drive unit is configured to drive and / or to manipulate a first and a second wheel of the medical device. The first and the second wheel are preferably comprised by and / or fixed on a chassis. In particular, the first and the second wheel are arranged on a common axle. The differential drive unit is configured to manipulate and / or to drive the first and the second wheel independently from each other. In other words, the differential drive unit can drive and / or run the first and the second wheel at different speeds. In particular, the method is configured and / or designed to decelerate the first and the second wheel, in particular the mobile medical device, by means of the differential drive unit. In other words, the differential drive unit can be used for deceleration in addition to active acceleration and / or movement of the medical device. The method is particularly configured to manipulate and / or to adjust the differential drive unit for deceleration. The method is particularly used to prevent a coasting behavior of the medical device in deceleration.

[0009] The medical device is particularly configured to realize a turning by driving and / or running the first and the second wheel at different speeds. In particular, the first and the second wheel are not actively turning wheels, which are pivotably configured, but a turning of the medical device can be realized by using different wheel speeds.

[0010] In a method step, which is also referred to as first determining step, a first wheel speed of the first wheel and a second wheel speed of the second wheel are determined. In particular, the first wheel speed and the second wheel speed are determined simultaneously and / or within a time interval of less than one second. The determination can comprise a measurement of the first and / or second wheel speed. Alternatively and / or additionally, the determination of the first and second wheel speed can comprise a calculation of the wheel speed based on geometric dimensions, wheel dimensions and / or measured variables. The determination can be performed, for example, by means of a first and a second sensor, wherein the first sensor determines the first wheel speed and the second sensor determines the second wheel speed. Alternatively, the first and second wheel speed can be determined by means of a position measurement, for example by means of a position measurement at different points in time and in the knowledge of the wheel dimensions.

[0011] In a further method step, which is also referred to as second determining step, a first brake variable of the first wheel and a second brake variable of the second wheel are determined and / or determined. The determination of the brake variables can comprise a calculation and / or a measurement. In particular, the determination and / or calculation of the first and second brake variable comprises a determination from the first and / or second wheel speed. The first and second brake variable form a respective related degree of deceleration of the wheel. The first and / or second brake variable can comprise and / or form, for example, an acceleration, a brake torque and / or a brake force. In particular, the first and / or second brake variable is configured for application by means of the differential drive unit. Alternatively and / or additionally, the first and / or second brake variable is configured and / or designed for application by means of a brake device. In particular, the first brake variable is determined on the basis of the first and second wheel speed. It is furthermore preferred to provide that the second brake variable is determined on the basis of the first and second wheel speed. It is provided here that a smaller brake variable is determined and / or determined for a wheel having a smaller wheel speed and a larger brake variable is determined for a wheel having a larger wheel speed. For example, the first wheel has a larger wheel speed, so that the first wheel speed is larger than the second wheel speed, so that the first brake variable to be determined is larger than the second brake variable.

[0012] In a further method step, the brake variables are used to decelerate the first and second wheel, in particular to decelerate the mobile medical device. For example, the first and second brake variable are forwarded and / or provided to the differential drive unit and / or to the brake unit for application. Subsequently, the differential drive unit and / or the brake unit apply the first and second brake variable. By applying the first and second brake variable, the first and second wheel are decelerated. In particular, the first and second brake variable are determined and / or the application is configured such that the first and second wheel are stopped simultaneously. The application of the first and second brake variable provides in particular that they are applied simultaneously.

[0013] It is particularly provided that, prior to determining the first and second brake variables, it is checked whether the first wheel speed is not equal to the second wheel speed. If it is determined that the first and second wheel speeds are not identical and / or a deceleration should take place, the method steps for determining the first and second brake variables and / or their application are carried out. If it is determined that the first wheel speed corresponds to the second wheel speed, it is preferably provided that, instead of two different brake variables being calculated, a common identical brake variable, in particular the maximum permissible brake variable, is applied. This is based on the idea that, when the speeds are identical, no cornering is taking place and a subsequent idling behavior of the medical device and / or of the non-driven wheels is not to be expected, so that the additional calculation steps and / or determination steps of the first and second brake variables do not have to be carried out. Instead of and / or in addition to checking whether the first wheel speed is not equal to the second wheel speed, the medical device, in particular the mobile mechanism, can comprise a curve sensor, for example a tilt sensor and / or a gyroscope, wherein, based on the measurement, it is determined whether a cornering is taking place. It can be provided here that, when a cornering is determined, the determination of the first and second brake variables is applied, in contrast, when it is determined that no cornering is taking place, two separate brake variables are not calculated and / or determined, but a uniform, in particular maximum permissible, brake variable is applied to the first and second wheels.

[0014] In an alternative design of the application it is provided that, when determining the brake variable of the wheel having the higher wheel speed, the maximum brake variable is applied and / or set. In other words, it can be provided here that no calculation is carried out from the first and second wheel speeds, but the maximum brake variable set and / or previously determined is applied. The maximum brake variable is in particular a variable specific to the mobile medical device, specific to the mobile mechanism and / or specific to the environment, for example for use in a hospital. In particular, the maximum brake variable can comprise and / or form a maximum permissible acceleration, a maximum permissible brake force and / or a maximum permissible brake torque. The maximum permissible acceleration, brake force and / or brake torque is calculated and / or set, for example on the basis that no danger to users, patients and / or objects and persons in the surroundings is to be expected. In particular, the maximum permissible acceleration, brake force and / or brake torque can be specific to the differential drive unit and / or brake unit, for example on the basis of its technical possibilities and limits. In other words, this design provides that the wheel having the higher wheel speed is decelerated with the maximum permissible brake variable and the slower wheel is decelerated with the brake variable to be calculated and / or determined, wherein the brake variable is determined on the basis of the first and / or second wheel speed, in particular on the basis of the maximum brake variable.

[0015] It is particularly preferred that the braking parameters of the further wheels are determined and / or calculated on the basis of the maximum braking parameter and the first and / or second wheel speed. It is provided in particular that the braking duration is determined on the basis of the maximum braking parameter and the greater wheel speed of the two wheel speeds. The braking duration describes in particular the duration required to decelerate the faster wheel with the maximum braking parameter. The braking parameter of the wheel with the lower wheel speed is determined in particular on the basis of the specific braking duration of the wheel with the higher wheel speed and the wheel speed of the wheel with the lower wheel speed. In particular, the braking parameter of the wheel with the lower speed is determined such that the same braking duration is required to decelerate the wheel with the lower wheel speed as for the wheel with the higher wheel speed. In other words, the determination of the first and second braking parameters is carried out such that the slower wheel comes to a standstill at the same time as the faster wheel when the maximum braking parameter is applied to the faster wheel.

[0016] It is provided in particular that the determination of the two braking parameters of the first and second wheel is carried out such that the first and second wheel are uniformly decelerated by the application of the braking parameters to be determined. In other words, the determination of the braking parameters is carried out under the condition that the deceleration time of the first wheel is equal to the deceleration time of the second wheel. By this condition it can be ensured that both wheels reach a standstill at the same point in time and that no coasting behavior of the medical device and / or one or more non-driven wheels occurs. The design of the application provides that, when determining the first and second braking parameters, the first and second braking parameters are determined such that, by the application of the first and second braking parameters, the wheel speed difference between the first and second wheel is uniformly reduced, in particular uniformly over the deceleration phase and / or the braking duration of the first and second wheel. It can be provided for example that the difference between the first wheel speed and the second wheel speed is reduced linearly. It is provided in particular that, by the application of the first and second braking parameters, the ratio of the first and second wheel speed remains constant. In particular, the application of the first and second braking parameters results in a linear reduction of the first and second wheel rotational speed.

[0017] It is particularly preferred that, prior to determining the first and second braking parameters, it is checked whether the first wheel and the second wheel have the same rotational direction. For example, it is checked whether the first and second wheel have a positive or negative wheel speed. Here, the design provides that, if it is determined that the two wheels have different rotational directions, the steps for determining the first and second braking parameters are not applied and / or carried out. For example, in the case of a determination of different rotational directions, a special braking program can be initiated, an error message can be output and / or the application of the braking parameters can be suppressed. Alternatively and / or additionally, as a condition for carrying out the method steps for determining the first and second braking parameters, it can be provided that the condition that the first wheel and the second wheel have the same rotational direction is set.

[0018] It is particularly preferred that it is determined in a predetermined step whether an activation element of the mobile medical device is manipulated. The activation element can comprise and / or form an emergency brake circuit and / or an emergency brake element, for example. The activation element is provided for being manipulated and / or activated by a user. For example, the activation element has to be activated and / or pressed in order to be able to activate and / or use the differential drive. If the activation element is not activated, it is particularly provided that the mobile medical device is decelerated, in particular as quickly as possible. It is preferably provided here that, as a condition for determining the first and second brake variables, it is checked and required that the activation element is not activated and / or manipulated. In other words, it can be provided that the determination step for determining the first and second brake variables is inhibited and / or deactivated in the case of an activated activation element. In other words, it can be provided that the steps for determining the first and second brake variables are only executed when the activation element is no longer manipulated.

[0019] A further subject matter of the application is a computer program, in particular a computer program product. The computer program and / or the computer program product are configured and / or designed for being executed on a computer, a computer device and / or a control device. The computer program product and / or the computer program in particular comprises program code. When the computer program, the computer program product and / or the program code are executed, the method is executed and / or supported in a computer-implemented manner as described above.

[0020] A further subject matter of the application is a control device, in particular for a mobile medical device. The control device is configured for executing, implementing and / or supporting the computer program, the computer program product and / or the method as described above. A further subject matter is a mobile medical device, wherein the mobile medical device comprises and / or implements the control device, the control device and / or the method described above. BRIEF DESCRIPTION OF DRAWINGS

[0021] It is in particular provided that features can be transferred between the different categories, in particular that method features can form device features and device features can form method features. Further advantages, effects and design solutions can be gathered from the attached drawings and their description. Herein:

[0022] Figure 1 An embodiment of a mobile medical device is shown;

[0023] Figure 2 A fragmentary view of a mobile medical device comprising a control device is shown;

[0024] Figure 3 A schematic method flow for decelerating a mobile medical device is shown;

[0025] Figure 4 A change of the wheel speed over time when decelerating a mobile medical device is shown. DETAILED DESCRIPTION

[0026] Figure 1 A mobile medical device 1 is shown, which is configured as a mobile head scanner or mobile C-arm, for example. Here, the actual imaging unit, for example a C-arm, can be supported on a mobile structure. The mobile medical device 1 can be controlled by a user 2, in particular mobile and / or steerable. To this end, the mobile medical device 1 comprises an operating device 3, which comprises and / or forms, in particular, activation elements. For example, the operating device 3 can comprise a force sensor, which is preferably used as an emergency brake. Furthermore, the operating device 3 can comprise at least one input means, for example a joystick, a button or a steering wheel, with which the user 2 can control and / or steer the movement, drive and / or travel of the mobile medical device 1.

[0027] The mobile medical device 1 comprises a chassis, which can comprise and / or be connected to a frame structure, for example. The chassis and / or the mobile medical device 1 comprises a plurality of wheels 4a to 4d, wherein the wheels 4a and 4b form driven wheels and the wheels 4c and 4d are passive support wheels. The wheels 4a and 4b are connected to a differential drive unit 5, for example via a shaft 6. The differential drive unit 5 is configured to drive and / or decelerate the wheels 4a and 4b. The differential drive unit 5 is configured to be able to drive the wheels 4a and 4b with different intensities in order to be able to achieve a turning travel, for example a turning travel at an angle ω, by different wheel speeds of the wheels 4a and 4b. In particular, the user 2 can set and / or select a target speed and / or select and / or determine a steering angle ω. The mobile medical device 1 comprises two sensors 8a, 8b, wherein the sensor 8a is configured to determine a first wheel speed 11a of the wheel 4a and the sensor 8b is configured to determine a second wheel speed 11b of the wheel 4b. The first and second wheel speeds 11a, 11b are provided in a data technology to a control means 9 of the mobile medical device 1.

[0028] The operating device 3 is configured to provide steering data, wherein the steering data, for example, contain information about whether an activation element is activated and / or whether there is contact with the user 2 or whether the user 2 is no longer in contact with the operating device 3 and no longer actively takes over the control. The steering data can also include user control data, which include a target speed and / or a steering angle.

[0029] The mobile medical device 1 comprises a control means 9, which is arranged in a data stream between the operating device 3 and the differential drive unit 5. The control means 9 is configured to determine and provide first and second brake variables 12a, 12b for decelerating the mobile medical device 1.

[0030] In order to illustrate the processes in the control device 9 and / or in the method 100 performed therefor for determining and / or providing the brake parameters 12a, 12b, Figure 2 A fragmentary view of the data- and / or signal-technical connections of the control device 9 is shown. The control device 9 is connected in data technology with the operating means 3 and with the differential drive unit 5. For this purpose, the control device 9 has a data input 10a and a data output 10b. On the data input 10a, the control device 9 is supplied with operating data by the operating means 3. On the data output 10b, the control device 9 provides adjustment and / or control signals for adjusting and / or controlling the differential drive unit 5. The differential drive unit 5 responds to the supplied signals by adapting the drive parameters and / or by applying the first and second brake parameters 12a, 12b.

[0031] Figure 3 An exemplary method flow of the method 100 for decelerating the mobile medical device 1 is shown. In a method step 200, a first wheel speed 11a of the first wheel 4a and a second wheel speed 11b of the second wheel 4b are determined. The determination of the wheel speeds 11a, 11b is performed, for example, by the sensors 8a, 8b.

[0032] In a method step 300, a first brake parameter 12a of the first wheel 4a and a second brake parameter 12b of the second wheel 4b are determined, wherein the brake parameters 12a, 12b describe the degree to which the respective wheel 4a, 4b is decelerated, wherein a smaller brake parameter is determined for a wheel having a smaller wheel speed compared to a wheel having a higher wheel speed.

[0033] In a method step 400, the first brake parameter 12a and the second brake parameter 12b are applied for decelerating the first and second wheels 4a, 4b. This step comprises providing the first and second brake parameters 12a, 12b to the differential drive unit 5, which simultaneously applies both brake parameters 12a, 12b such that the wheels 4a, 4b are stopped simultaneously.

[0034] Figure 4 The time-dependent change of the first and second wheel speeds (12a, 12b) is shown exemplarily. The mobile medical device is in a turning maneuver until a time point tl is reached, wherein the first wheel (4a) has a larger wheel speed (12a) compared to the second wheel (4b). The mobile medical device performs a turning maneuver in the direction of the second wheel (4b) at this point in time.

[0035] At the point in time t1, the activation element is released and the first and second brake variables (13a, 13b) are determined. For this purpose, the method according to the application is used. In step 200, the first and second wheel speeds (12a, 12b) are detected, wherein it is determined that the first wheel speed (12a) is greater than the second wheel speed (12b). In order to decelerate the faster wheel, here the first wheel (4a), the maximum permissible (negative) acceleration a max is applied. On the basis of the first wheel speed (12a) and the acceleration a max , in the method step (300) the deceleration time t Brems,1 is determined, for example, by t max = a Brems,1 / v1, wherein v1 represents the tangential speed of the first wheel (4a). In order to determine the second brake variable (13b) it is required that the application of the second brake variable (13b) to the second wheel (4b) results in a deceleration time t Brems,2 which is equal to the deceleration time t Brems,1 of the first wheel (4a). In other words, it is required that t Brems,2 = t Brems,1 = a2 / v2. Subsequently, the acceleration a2 is determined and applied as the second brake variable (13b).

Claims

1. A method (100) for decelerating a mobile medical device (100), wherein, The mobile medical device (100) comprises a differential drive unit (5) for driving a first wheel (4a) and a second wheel (4b), the method comprising the following method steps: - determining (200) a first wheel speed (12a) of the first wheel (4a) and a second wheel speed (12b) of the second wheel (4b), - determining (300) a first braking parameter (13a) for the first wheel (4a) and a second braking parameter (13b) for the second wheel (4b), wherein the braking parameters (13a, 13b) describe a degree of deceleration of the respective wheel (4a, 4b), wherein a smaller braking parameter (13a, 13b) is determined for a wheel (4a, 4b) having a smaller wheel speed (12a, 12b) than for a wheel (4a, 4b) having a higher wheel speed (12a, 12b), - applying (400) the first braking parameter (13a) and the second braking parameter (13b) for decelerating the first wheel (4a) and the second wheel (4b).

2. The method (100) according to claim 1, characterized in that In determining (300) the braking parameter (13a, 13b) for the wheel (4a, 4b) having the higher wheel speed (12a, 12b), a maximum braking parameter, in particular a maximum allowed acceleration, a maximum allowed braking force and / or a maximum allowed braking torque, is applied as the braking parameter (13a, 13b).

3. The method (100) according to claim 2, characterized in that A braking duration is determined on the basis of the maximum braking parameter and the wheel speed (12a, 12b) of the associated wheel (4a, 4b), wherein the braking parameter (13a, 13b) for the wheel (4a, 4b) having the lower wheel speed (12a, 12b) is determined on the basis of the specific braking duration and the wheel speed (12a, 12b).

4. The method (100) according to any one of the preceding claims, characterized in that, In determining (300) the braking parameters (13a, 13b), the first braking parameter (13a) and the second braking parameter (13b) are determined such that, by applying (400) the braking parameters (13a, 13b), the first wheel (4a) and the second wheel (4b) have the same deceleration time.

5. The method (100) according to any one of the preceding claims, characterized by, In determining (300) the braking parameters (13a, 13b), the first braking parameter (13a) and the second braking parameter (13b) are determined such that, by applying (400) the first braking parameter (13a) and the second braking parameter (13b), the first wheel (4a) and the second wheel (4b) stop at the same time.

6. The method (100) according to any one of the preceding claims, characterized by, In determining (300) the braking parameters (13a, 13b), the first braking parameter (13a) and the second braking parameter (13b) are determined such that, by applying (400) the first braking parameter (13a) and the second braking parameter (13b), a wheel speed difference between the first wheel (4a) and the second wheel (4b) is uniformly reduced in the deceleration phase. In determining (300) the braking parameters (13a, 13b), the first braking parameter (13a) and the second braking parameter (13b) are determined such that, by applying (400) the first braking parameter (13a) and the second braking parameter (13b), a wheel speed difference between the first wheel (4a) and the second wheel (4b) is uniformly reduced in the deceleration phase.

7. The method (100) according to any one of the preceding claims, characterized by, checking whether the first wheel (4a) and the second wheel (4b) have the same direction of rotation before determining (300) the brake variable (13a, 13b), wherein in the case of the same direction of rotation the method steps of determining (200) the brake variable (13a, 13b) are applied and in the case of a different direction of rotation a special braking procedure is applied instead of the method steps of determining (300) the brake variable (13a, 13b).

8. The method (100) according to any one of the preceding claims, characterized by, determining whether an activation element of the mobile medical device (1) is manipulated before determining (300) the brake variable (13a, 13b) and / or before determining (200) the first wheel speed (12a) and the second wheel speed (12b), wherein the steps of determining (300) the brake variable (13a, 13b) and / or determining (200) the first wheel speed (12a) and the second wheel speed (12b) are only executed when the activation element is no longer manipulated.

9. A computer program for execution on a calculator, computer and / or control device, wherein, The computer program comprises program code and is configured to perform, implement and / or apply the method (100) according to any one of the preceding claims when it is executed.

10. A control device (9) for a mobile medical device (1) configured to perform, apply and / or implement a computer program and / or the method (100) according to any one of claims 1 to 8.

11. A mobile medical device comprising a differential drive unit (5), a first wheel (4a), a second wheel (4b) and at least one further wheel (4c, 4d), wherein, The differential drive unit (5) is configured to drive the first wheel (4a) and the second wheel (4b) characterized by the control device (9) according to claim 10. The differential drive unit (5) is configured to drive the first wheel (4a) and the second wheel (4b) characterized by the control device (9) according to claim 10.

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