Medical device base and medical device system

Abstract

A medical device base and a medical device system are disclosed. The medical device base includes a pair of front wheels, a pair of rear wheels, a first position sensor positioned intermediate the pair of front wheels, a second position sensor positioned intermediate the pair of rear wheels, and a controller. The controller calculates a gear ratio of the rear wheels based on a position of the first position sensor and a position of the second position sensor. The medical device base and system of the present invention does not require a track to control movement nor does it require an absolutely flat surface. It can be used on relatively flat surfaces, is low cost, and has low environmental dependency.

Description

Technical Field

[0001] This invention relates to medical device systems, and in particular to medical device bases. Background Technology

[0002] During CT scans, patients are typically moved using a patient support system (examination bed). However, in certain special cases, such as during surgery or with open wounds, patients cannot be moved and CT scans are performed using a mobile gantry. This necessitates a mobile gantry base capable of supporting and transporting the gantry. With this base, the gantry can also be transported outside the scanning room and used in several rooms.

[0003] For mobile CT, motion accuracy is crucial, as it directly affects the quality of the scanned images. However, the motion accuracy of mobile CT is affected by a variety of factors, including ground flatness and the installation precision of the mechanical structure. Summary of the Invention

[0004] In view of this, the present invention proposes a medical device base and a medical device system.

[0005] According to a first aspect of the present invention, a medical device base is provided, comprising a pair of front wheels, a pair of rear wheels, a first position sensor located between the pair of front wheels, a second position sensor located between the pair of rear wheels, and a controller;

[0006] The controller calculates the gear ratio of the rear wheel based on the positions of the first position sensor and the second position sensor.

[0007] In one embodiment, the position deviation of the first position sensor is E. p (n), then the controller calculates E according to the following formula. p (n):

[0008]

[0009] Where N is a positive integer, dt is the sampling time interval, and K pp K pi K pd These are the proportional integral and differential coefficients for the relevant positions.

[0010] In one embodiment, the position of the first position sensor is P1, the position of the second position sensor is P2, and the angular deviation of the second position sensor is E. a (n), then the controller calculates E according to the following formula. a (n):

[0011]

[0012] Where d(P2-P1) is the position difference between the first position sensor and the second position sensor.

[0013] In one embodiment, the gear ratio of the rear wheel is GR, and the controller calculates GR according to the following formula:

[0014]

[0015] Among them, K ap K ai K ad These are the proportional integral and differential coefficients for the relevant angles.

[0016] In one embodiment, N∈[25, 1000].

[0017] In one embodiment, the front wheel includes a motion encoder, a motion motor, and a motion drive, and the rear wheel includes a steering encoder, a steering motor, and a steering drive.

[0018] According to a second aspect of the present invention, a medical device system is provided, comprising a medical device and a medical device base as described above, the medical device being placed on the medical device base, and a controller sending the gear ratio of the rear wheel to the medical device.

[0019] The medical device base and system of this invention do not require tracks to control movement, nor do they require an absolutely flat surface. It can be used on relatively flat surfaces, is inexpensive, and has low environmental dependence. Attached Figure Description

[0020] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which will make the above and other features and advantages of the present invention more apparent to those skilled in the art. In the drawings:

[0021] Figure 1 This is a schematic diagram of the structure of a medical device base according to an embodiment of the present invention.

[0022] Figure 2 This is a functional block diagram of a medical device base according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram showing the position and angle deviation of the medical device base according to an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the movement of a medical device base according to an embodiment of the present invention.

[0025] The reference numerals used in the above figures are as follows:

[0026] 100 Medical equipment base; 110 Laser beam

[0027] 101 Steering Motor 111 Motion Drive

[0028] 102 Base plate 112 Position deviation

[0029] 103 Steering Encoder 113 Controller

[0030] 104 Rear wheel 114 Angle deviation

[0031] 105 Steering Drive 116 Path Planning

[0032] 106 Front wheel 117 Medical equipment

[0033] 107 Moving motor 118 Origin

[0034] 108 Second position sensor 120 First position sensor

[0035] 109 Mobile Encoder Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the following embodiments are provided to further illustrate the present invention in detail.

[0037] Figure 1 This is a schematic diagram of the structure of a medical device base 100 according to an embodiment of the present invention. Figure 2 This is a functional block diagram of a medical device base 100 according to an embodiment of the present invention. Ideally, the medical device base 100 would travel along the Y direction, but in reality, it would deviate in the X direction. The gantry has significant motion inertia, and the moving mechanism exhibits backgap, making it difficult to measure static errors. To reduce the impact on scanning and reconstruction, the deviation in the X direction should be controlled within 2 mm.

[0038] like Figure 1 and 2 As shown, the medical device base 100 includes a base plate 102, a pair of front wheels 106, a pair of rear wheels 104, a first position sensor 120 located between the pair of front wheels 106, a second position sensor 108 located between the pair of rear wheels 104, and a controller 113. The first position sensor 120 and the second position sensor 108 emit laser beams 110.

[0039] like Figure 2As shown, the front wheel 106 includes a motion encoder 109, a motion motor 107, and a motion drive 111, while the rear wheel 104 includes a steering encoder 103, a steering motor 101, and a steering drive 105. A first position sensor 120 and a second position sensor 108 send their position information to the controller 113. The controller 113 calculates the gear ratio of the rear wheel 104 based on the positions of the first position sensor 120 and the second position sensor 108. A medical device 117 can be placed on the medical device base 100, and the controller 113 can send the gear ratio to the medical device 117.

[0040] The offsets of two positions on the base 100 relative to the direction of travel can be obtained from the first position sensor 120 and the second position sensor 108. The position of the first position sensor 120 is P1, and the position of the second position sensor 108 is P2. Therefore, the position P1 of the first position sensor 120 is the position error, and P2 - P1 is the angle error.

[0041] Figure 3 This is a schematic diagram of the position deviation 112 and angle deviation 114 of the medical device base 100 according to an embodiment of the present invention.

[0042] First, to reduce the position error of P1, the position deviation is used as the input to the first PID (Proportional-Integral-Derivative) loop, employing a semi-position PID algorithm. The deviation values ​​of the position sensor at N sampling points are recorded as the input deviation values, where N can range from 25 to 1000. This increases the reliability of deviation correction while reducing the processor load.

[0043] The position deviation of the first position sensor 120 is F. p (n), controller 113 can calculate F according to the following formula. p (n):

[0044]

[0045] Where N is a positive integer, dt is the sampling time interval, and K pp K pi K pd These are the proportional, integral, and differential coefficients for the relevant positions, which can be obtained through testing and adjustment.

[0046] The corrected deviation is then added to the adjustment of the angle deviation, so that the adjustment of the angle deviation approaches 0 while reducing the position deviation.

[0047] The angular deviation of the second position sensor 108 is E. a (n), then controller 113 can calculate E according to the following formula. a (n):

[0048]

[0049] Wherein, d(P2-P1) is the position difference between the first position sensor 120 and the second position sensor 108. In this embodiment, the unit of d(P2-P1) is micrometers, so it needs to be divided by 1000 for unit conversion.

[0050] The correction value obtained after this PID loop is compared with the existing speed difference for further correction. At the same time, in order to increase the flexibility and smoothness of the motion, the rear wheel steering angle is added. The angle of the rear wheel steering angle is based on the differential deviation to be corrected, with the center of motion as the origin, and the deflection angle is obtained in real time.

[0051] If the gear ratio of the rear wheel 104 is GR, then the controller 113 can calculate GR according to the following formula:

[0052]

[0053] Among them, K ap K ai K ad These are the proportional, integral, and differential coefficients for the relevant angles, which can be obtained through testing and adjustment.

[0054] Figure 4 This is a schematic diagram of the movement of a medical device base 100 according to an embodiment of the present invention. The rear wheel 104 deflects around the origin 118, causing the base plate 102 to have path planning 116, thereby returning to the ideal travel route Y.

[0055] The high-precision position sensor (PSD) has a measurement range of + / -17mm and a resolution of 0.01mm. In this embodiment, the distance between the steering wheels (rear wheels) is 2605mm, and the diameter is 198mm. If only the travel wheels (front wheels) are controlled synchronously in real time, a deviation of 5-7mm will occur when moving 1000mm at 100mm / s. With the controller of this embodiment, the deviation is reduced to 2mm.

[0056] The present invention also provides a medical device system, including a medical device 117 and a medical device base 100, wherein the medical device 117 is placed on the medical device base 100, and the controller 113 sends the gear ratio of the rear wheel 104 to the medical device 117.

[0057] The medical device base and system of this invention do not require tracks to control movement, nor do they require an absolutely flat surface. It can be used on relatively flat surfaces, is inexpensive, and has low environmental dependence.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A medical device base (100) includes a pair of front wheels (106), a pair of rear wheels (104), a first position sensor (120) located between the pair of front wheels (106), a second position sensor (108) located between the pair of rear wheels (104), and a controller (113). The controller (113) calculates the gear ratio of the rear wheel (104) based on the position of the first position sensor (120), the position of the second position sensor (108), and the position deviation of the first position sensor.

2. The medical device base (100) as described in claim 1, characterized in that, The position deviation of the first position sensor (120) is Then the controller (113) calculates according to the following formula. : in, It is a positive integer. , , These are the proportional integral and differential coefficients for the relevant positions.

3. The medical device base (100) as described in claim 2, characterized in that, The position of the first position sensor (120) is The position of the second position sensor (108) is The angular deviation of the second position sensor (108) is Then the controller (113) calculates according to the following formula. : in, The position difference between the first position sensor (120) and the second position sensor (108).

4. The medical device base (100) as described in claim 3, characterized in that, The gear ratio of the rear wheel (104) is Then the controller (113) calculates according to the following formula. : in, , , These are the proportional integral and differential coefficients for the relevant angles.

5. The medical device base (100) as described in claim 2, characterized in that, 。 6. The medical device base (100) as described in claim 1, characterized in that, The front wheel (106) includes a motion encoder (109), a motion motor (107), and a motion drive (111), and the rear wheel (104) includes a steering encoder (103), a steering motor (101), and a steering drive (105).

7. A medical device system comprising a medical device (117) and a medical device base (100) as claimed in any one of claims 1 to 6, wherein the medical device (117) is placed on the medical device base (100), and the controller (113) sends the gear ratio of the rear wheel (104) to the medical device (117).

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