Movable body control device and storage medium

Abstract

To provide a technique that allows easy adjustment of a movable body such as a gantry and a table.SOLUTION: A device includes: a unit including a cylinder and a piston; a subject support unit that moves in accordance with relative movement of the cylinder and the piston; a control board that generates a control signal including a first pulse width W based on an operation signal T1 input by a user operation; and an oil amount adjustment unit that adjusts the amount of oil contained in the cylinder based on the first pulse width W, where the control board determines a value of a gain K based on a deviation amount DM, calculates a second pulse width W2 based on the deviation amount DM and the determined gain value, and generates a control signal including the second pulse width W2 when a next operation signal T2 is input, and the oil amount adjustment unit adjusts the amount of oil in the cylinder based on the second pulse width W2.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a movable body control device that controls a movable body, and a storage medium on which instructions for operating the movable body control device are stored. [Background technology]

[0002] CT systems are known as medical devices that capture images of a subject non-invasively. CT systems are widely used in hospitals and other medical facilities because they can acquire cross-sectional images of the subject in a short scanning time.

[0003] A CT system applies a predetermined voltage to the cathode-anode tube of an X-ray tube to generate X-rays. The generated X-rays pass through the subject and are detected by a detector. The CT system reconstructs a CT image of the subject based on the data detected by the detector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2014-161392 Summary of the Invention [Problem to be solved by the invention]

[0005] When a patient is imaged with a CT system, the patient is placed on a table. After the patient is placed on the table, the operator adjusts the height of the table so that the area of ​​the patient to be imaged is properly positioned in the bore of the gantry.

[0006] When adjusting the table height, the operator generally first roughly adjusts the table height and then finely adjusts it. Inching is a well-known method of fine adjustment. CT systems configured to allow fine adjustment by inching are equipped with a control panel that allows the operator to finely adjust the table height. When the operator operates the control panel, the table height is finely adjusted in accordance with the operation.

[0007] Table height mechanisms typically use hydraulic or electric servos. Electric servos excel at fine adjustments and high-precision control, but are not good at generating large forces and are expensive. On the other hand, hydraulic systems are inexpensive and good at generating large forces, but they have the disadvantage of being difficult to adjust fine adjustments. Hydraulic systems are often used for CT system tables, where price is a priority. Hydraulic systems use valves to adjust the flow rate of the working fluid (oil). When an operator operates a control panel, the valve opens and closes to adjust the table height. However, with hydraulic systems, the amount of table height change corresponding to a single operation of the control panel can deviate from the desired value (target change). As a result, the operator must operate the control panel multiple times to adjust the table height to the desired position, which takes time and increases the operator's workload. To alleviate this problem, the valve flow rate is currently adjusted for each table during the final stage of table manufacturing and inspection. However, this adjustment is only performed under specific conditions (e.g., temperature conditions). Therefore, when the table height is adjusted under conditions that differ from the specified conditions, the operator must repeatedly operate the control panel to adjust the table height to the desired position. Furthermore, adjusting the valve flow rate during table manufacturing inspection initially matches the desired value (target change amount), but as the table continues to be used, there is a risk that the value will gradually deviate from the desired value (target change amount), and there are limits to adjusting the valve flow rate during table manufacturing inspection. To address this issue, tables using hydraulic servos are known, but it is not practical to use a hydraulic servo mechanism for a table that must be inexpensive.

[0008] Furthermore, some CT systems are equipped with a tilt mechanism that can tilt the gantry. If this tilt mechanism uses hydraulics, the operator may have to operate the control panel multiple times to match the gantry tilt angle to the desired tilt angle, which again places a heavy burden on the operator.

[0009] Therefore, there is a demand for a technique that allows for easy adjustment of movable bodies such as a gantry and a table. [Means for solving the problem]

[0010] A first aspect of the present invention provides a unit including a cylinder and a piston, wherein at least a portion of the piston is disposed within the cylinder, and one of the cylinder and the piston moves relative to the other by adjusting an amount of a working fluid within the cylinder; a movable body that moves in response to the relative movement of the cylinder and the piston; a control unit that generates, based on a first operation signal input by a user's operation for moving the movable body by a target change amount, a control signal including a first pulse width corresponding to the target change amount so that the movable body moves by the target change amount; a fluid amount adjusting unit that adjusts the amount of working fluid contained in the cylinder based on the first pulse width; Including, The control unit determining the amount of movement of the movable body by adjusting the amount of working fluid in the cylinder; determining a gain value based on a deviation between the movement amount of the movable body and the target change amount; calculating a second pulse width based on the deviation amount and the determined gain value; generating a control signal including the second pulse width when a second operation signal for moving the movable body by a target change amount is input after the first operation signal; Run The fluid amount adjusting unit is a movable body control device that adjusts the amount of working fluid in the cylinder based on the second pulse width.

[0011] A second aspect of the present invention is a non-transitory computer-readable storage medium included in a movable body control device or a non-transitory computer-readable storage medium capable of communicating with a movable body control device, The movable body control device includes: a unit including a cylinder and a piston, at least a portion of the piston being disposed within the cylinder, and configured such that an amount of working fluid within the cylinder is adjusted to move one of the cylinder and the piston relative to the other; a movable body that moves in response to the relative movement of the cylinder and the piston; a control unit that generates, based on a first operation signal input by a user's operation for moving the movable body by a target change amount, a control signal including a first pulse width corresponding to the target change amount so that the movable body moves by the target change amount; a fluid amount adjusting unit that adjusts the amount of working fluid contained in the cylinder based on the first pulse width; Including, the control unit includes one or more processors; The instructions contained in the storage device, when executed by the one or more processors, cause the one or more processors to: determining the amount of movement of the movable body by adjusting the amount of working fluid in the cylinder; determining a gain value based on a deviation between the movement amount of the movable body and the target change amount; calculating a second pulse width based on the deviation amount and the determined gain value; generating a control signal including the second pulse width when a second operation signal for moving the movable body by a target change amount is input after the first operation signal; Execute The fluid amount adjusting unit is a non-transitory computer-readable storage medium that adjusts the amount of working fluid in the cylinder based on the second pulse width. [Effects of the Invention]

[0012] In the present invention, a gain value corresponding to the target change amount is determined based on the deviation between the movement amount of the movable body and the target change amount. Therefore, the gain value is determined taking into consideration the actual deviation amount, and by using the determined gain value, a second pulse width that reduces the deviation between the actual displacement amount of the movable body and the target change amount can be calculated. When a second operation signal is input, the movement amount of the movable body is adjusted based on a control signal including the second pulse width, so that the movement amount of the movable body can be brought sufficiently close to the target change amount, thereby reducing the workload on the user in adjusting the movable body. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of a CT system 100 according to a first embodiment. [Figure 2] FIG. 2 is an enlarged view of the operation panel 10. [Figure 3] 10 is an explanatory diagram of a case where the up button 12 is tapped. FIG. [Figure 4] 10 is an explanatory diagram of a case where the down button 13 is tapped. [Figure 5] FIG. 2 is a block diagram of a table and a table control device. [Figure 6] FIG. 2 is a block diagram of a table and a table control device. [Figure 7] 4 is a diagram showing a pulse width W and a descending amount D of the table 300 corresponding to a tap operation by an operator 401. FIG. [Figure 8] 10 is an explanatory diagram illustrating a case where the amount of lowering D of the table 300 deviates from the target amount of change TW. FIG. [Figure 9] 10 is a diagram showing an operation flow of the table 300 when fine-tuning the height of the table 300 according to this embodiment. FIG. [Figure 10] 10 is a diagram showing the pulse width W and the amount of lowering D of the table 300 corresponding to the operation of the operator 401. FIG. [Figure 11] FIG. 10 is a flow chart of a method for calculating the pulse width W2 in step ST6. [Figure 12] The flow when the pulse width is set to a fixed value is shown below. [Figure 13] FIG. 10 is a diagram showing calculation results. [Figure 14] FIG. 10 is a diagram showing an example in which another operation for adjusting the height of the table is performed between operations T1 to T5. [Figure 15] 10 is an explanatory diagram illustrating a case where the forward tilt button 14 is tapped. FIG. [Figure 16] FIG. 10 is an explanatory diagram of an operation panel 10 according to a second embodiment. [Figure 17] 10 is an explanatory diagram illustrating a case where the forward tilt button 14 is tapped. FIG. [Figure 18] 10 is an explanatory diagram illustrating a case where the backward tilt button 15 is tapped. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a description will be given of an embodiment of the invention, but the present invention is not limited to the following embodiment.

[0015] (First embodiment) FIG. 1 is a perspective view of a CT system 100 according to the first embodiment. CT system 100 includes a gantry 200 and a table 300. Gantry 200 and table 300 are installed in a scan room.

[0016] The gantry 200 has a bore 201 into which a subject 400 is transferred and scanned.

[0017] In addition, an operation panel 10 that can be operated by an operator 401 is attached to the front of the gantry 200 (see FIG. 2).

[0018] FIG. 2 is an enlarged view of the operation panel 10. As shown in FIG. The operation panel 10 includes a button section 11 on which control buttons are arranged, and a display section 16. The button section 11 includes an up button 12 for raising the height of the table 300, a down button 13 for lowering the height of the table 300, and the like.

[0019] When the operator 401 wants to roughly adjust the height of the table 300, the operator 401 presses and holds the up button 12 or the down button 13. For example, when the operator 401 wants to continuously increase the height of the table 300, the operator 401 presses and holds the up button 12. When the up button 12 is pressed and held by the operator 401, the height of the table 300 increases continuously while the operator 401 holds the up button 12. On the other hand, when the operator 401 wants to continuously decrease the height of the table 300, the operator 401 presses and holds the down button 13. When the down button 13 is pressed and held by the operator 401, the height of the table 300 decreases continuously while the operator 401 holds the down button 13.

[0020] Furthermore, when the operator 401 wishes to finely adjust the height of the table 300, the operator 401 performs an operation of pressing the up button 12 or the down button 13 and immediately releasing the button 12 or 13 (hereinafter referred to as a "tap operation"). FIG. 3 is an explanatory diagram of the case where the up button 12 is tapped. The table 300 shown in the left half of FIG. 3 shows the table height before the up button 12 is tapped, and the table 300 shown in the right half of FIG. 3 shows the table height after the up button 12 is tapped. The table 300 is set to rise by a target change amount TV with one tap operation. In FIG. 3, the target change amount TV is exaggerated to make it easier to understand, but in reality, the target change amount TV is a value of approximately TV = 0.1 (mm) to 0.5 (mm). Therefore, the operator 401 can finely control the amount of rise in the height of the table 300 by performing a tap operation on the up button 12.

[0021] On the other hand, FIG. 4 is an explanatory diagram of the case where the down button 13 is tapped. The table 300 shown in the left half of FIG. 4 shows the height of the table before the down button 13 is tapped, and the table 300 shown in the right half of FIG. 4 shows the height of the table after the down button 13 is tapped. The table 300 is lowered by the target change amount TW with one tap. In FIG. 4, the target change amount TW is exaggerated to make it easier to understand, but in reality, the target change amount TW is a value of about TW = 0.1 (mm) to 0.5 (mm). Therefore, by tapping the down button 13, the amount of lowering of the height of the table 300 can be precisely controlled.

[0022] The display unit 16 of the operation panel 10 includes a display area 17. The display area 17 is an area where the current height of the table 300 is displayed.

[0023] Therefore, the operator 401 can adjust the height of the table 300 by tapping the up button 12 or the down button 13 while checking the current height of the table 300 on the display unit 16. Next, a control device that controls the height of the table in response to an operation from the operation panel 10 will be described.

[0024] FIG. 5 is a block diagram of the table and the table control device. Table 300 includes a base 301, legs 302, and a subject support 303. Subject support 303 supports a subject (such as a patient). Legs 302 connect base 301 and subject support 303. Legs 302 are configured to be extendable in the height direction of table 300, and extend and retract in accordance with changes in the height of table 300. Table 300 also has a table control device 500 that controls the height of the table. The table control device 500 will be described below.

[0025] The table control device 500 has a hydraulic device 20 for adjusting the height of the subject support portion 303 .

[0026] The hydraulic device 20 includes a unit 23 including a cylinder 21 and a piston 22, an oil tank 24, a supply pipe 25 that supplies oil in the oil tank 24 to the cylinder 21, a discharge pipe 26 that discharges the oil in the cylinder 21 to the oil tank 24, and an oil amount adjustment unit 27 that adjusts the amount of oil in the cylinder 21.

[0027] Although the hydraulic device 20 is attached to the table 300, in Fig. 5, in order to make the components of the hydraulic device 20 easier to understand, some of the components of the hydraulic device 20 are shown protruding from the table 300. Also, in Fig. 5, in order to make the structure of the unit 23 including the cylinder 21 and the piston 22 easier to understand, the unit 23 is shown enlarged. The components of the hydraulic system 20 will be described below in order.

[0028] The unit 23 is configured such that at least a portion of the piston 22 is disposed within the cylinder 21, and the amount of oil within the cylinder 21 is adjusted to allow one of the cylinder 21 and the piston 22 to move relative to the other. For example, the piston 22 may be configured to reciprocate relative to the cylinder 21, or the cylinder 21 may be configured to reciprocate relative to the piston 22, or the cylinder 21 and the piston 22 may be configured to reciprocate relative to each other. Furthermore, the cylinder 21 and the piston 22 may be configured such that the angle α between the cylinder 21 and the piston 22 is maintained at a fixed angle while the height of the subject support member 303 is being adjusted, or such that the angle α is continuously changed. The height of the subject support member 303 can be adjusted by the above-described configuration of the cylinder 21 and the piston 22. The method for adjusting the height of the subject support member 303 in this embodiment will be described in detail later.

[0029] The hydraulic device 20 also includes an oil tank 24, a supply pipe 25 that supplies oil in the oil tank 24 to the cylinder 21, a discharge pipe 26 that discharges the oil in the cylinder 21 to the oil tank 24, and an oil amount adjustment unit 27 that adjusts the amount of oil in the cylinder 21.

[0030] The oil amount adjusting unit 27 includes a pump 28 and a valve 29. The pump 28 is configured to supply oil from the oil tank 24 to the cylinder 21 through a supply pipe 25. The valve 29 is configured to discharge the oil from the cylinder 21 through a discharge pipe 26 and return the oil to the oil tank 24. Note that although oil is used as the working fluid of the hydraulic device 20 in this embodiment, a fluid other than oil can also be used as the working fluid.

[0031] Table control device 500 also includes control board 30 and inverter 40. Control board 30 and inverter 40 are configured to control the operation of hydraulic device 20. Control board 30 and inverter 40 will be described below.

[0032] Based on an operation signal for raising and lowering the subject support member 303 by a target amount of change, the control board 30 generates a control signal including a control pulse width corresponding to the target amount of change so that the subject support member 303 is raised and lowered by the target amount of change. The control board 30 is equipped with a storage device 37. The storage device 37 includes one or more storage media for storing programs, instructions to be executed by a processor, and the like. The storage medium may be, for example, one or more non-transitory computer-readable storage media. The storage medium may include, for example, a hard disk drive, a floppy disk drive, a compact disk read / write (CD-R / W) drive, a digital versatile disk (DVD) drive, a flash drive, and / or a solid-state recording drive. Note that although FIG. 5 illustrates the control board 30 as including one storage device 37, the control board 30 may include multiple storage devices 37. Furthermore, the multiple storage devices 37 may be provided on the control board 30 or may be distributed between the control board 30 and other components other than the control board 30.

[0033] The control board 30 has a converter 31. The converter 31 is connected to the operation panel 10. The converter 31 receives an operation signal SB0 input by the operator 401 operating the button 12 or 13.

[0034] For example, when the operator 401 presses the up button 12 for a long time, the operation signal SB0 represents the operation signal SB1 for continuously raising the height of the table 300.

[0035] On the other hand, when the operator 401 taps the up button 12, the operation signal SB0 produces a signal SB2 for raising the table 300 by a predetermined target change amount TV (see FIG. 3). Referring to FIG. 3, the target change amount TV is exaggerated to make it easier to understand, but in reality, the target change amount TV is a value of about TV=0.1 (mm) to 0.5 (mm).

[0036] Furthermore, when the operator 401 performs an operation of pressing and holding the lowering button 13, the operation signal SB0 represents a signal SB3 for continuously lowering the height of the table 300.

[0037] On the other hand, when the operator 401 taps the lowering button 13, the operation signal SB0 represents a signal SB4 for lowering the height of the table 300 by a predetermined target change amount TW (see FIG. 4). With reference to FIG. 4, the target change amount TW is exaggerated to make it easier to understand, but in reality, the target change amount TW is a value of about TW=0.1 (mm) to 0.5 (mm).

[0038] The target change amount TV when raising the height of the table 300 is the same as the target change amount TW when lowering the height of the table 300 (i.e., TV=TW). However, it is also possible for TV≠TW.

[0039] When converter 31 receives operation signal SB0 from button 12 or 13, it converts the voltage of operation signal SB0 and outputs voltage-converted signal SB01 (SB11, SB21, SB31, SB41). Voltage-converted signal SB11 is a signal including a command to continuously raise the height of table 300, and voltage-converted signal SB21 is a signal including a command to raise the height of table 300 by target change amount TV. Voltage-converted signal SB31 is a signal including a command to continuously lower the height of table 300, and voltage-converted signal SB41 is a signal including a command to lower the height of table 300 by target change amount TW.

[0040] The control board 30 also includes a processor 32. The processor 32 generates a control signal for controlling the oil amount adjusting unit 27 of the hydraulic device 20 based on the signal SB01 received from the converter 31. Although the control board 30 is shown in FIG. 5 as including one processor 32, the control board 30 may include multiple processors 32. Furthermore, the multiple processors 32 may be provided on the control board 30, or may be provided distributed between the control board 30 and other components other than the control board 30.

[0041] When the processor 32 receives from the converter 31 a signal SB11 including a command to continuously raise the height of the table 300, it generates a control signal SC11 to continuously supply oil to the cylinder 21. This control signal SC11 is supplied to the buffer 33, which then processes the signal to generate a control signal SC111, which is then supplied to the inverter 40. Upon receiving the control signal SC111, the inverter 40 supplies an AC signal SD1 from the AC source 41 to the pump 28. Based on the AC signal SD1, the pump 28 continuously supplies oil from the oil tank 24 to the cylinder 21. This causes the cylinder 21 to move in the direction of arrow A relative to the piston 22, resulting in the subject support member 303 continuously rising. In this manner, the subject support member 303 constitutes a movable body that moves in response to the relative movement of the cylinder 21 and the piston 22.

[0042] Furthermore, when the processor 32 receives from the converter 31 a signal SB21 including a command to raise the height of the table 300 by the target change amount TV, the processor 32 generates a control signal SC12 for supplying an amount of oil corresponding to the target change amount TV to the cylinder 21. This control signal SC12 is a pulse signal SP, and the pulse width Q of the control signal SC12 represents the time corresponding to the target change amount TV. For example, the pulse width Q is 330 ms. This control signal SC12 is supplied to the buffer 33, which then processes the control signal SC121 and supplies it to the inverter 40. Upon receiving the control signal SC121, the inverter 40 supplies the AC signal SD2 from the AC source 41 to the pump 28 for a period corresponding to the pulse width Q (= 330 ms). Based on the AC signal SD2, the pump 28 supplies an amount of oil corresponding to the pulse width Q (= 330 ms) from the oil tank 24 to the cylinder 21. Therefore, the pump 28 can adjust the amount of oil contained in the cylinder 21 based on the pulse width Q (= 330 ms). As a result, the cylinder 21 is finely adjusted in the direction of the arrow A, and the subject support part 303 is raised by the target change amount TV.

[0043] Furthermore, when the processor 32 receives from the converter 31 a signal SB31 including a command to continuously lower the height of the table 300, it generates a control signal SC21 to continuously supply oil to the cylinder 21. This control signal SC21 is supplied to the buffer 34, which then processes it as a control signal SC211 and supplies it to the TFT 35. When the control signal SC211 is supplied, the TFT 35 turns on. When the TFT 35 turns on, a predetermined reference voltage Ref is applied to the valve 29, opening the valve 29. At this time, the TFT 35 maintains the on state while the operator 401 presses the down button 13. This causes the valve 29 to discharge oil from the cylinder 21 into the oil tank 24. This causes the cylinder 21 to move in the direction of arrow B, resulting in the continuous lowering of the subject support 303.

[0044] Furthermore, when the processor 32 receives from the converter 31 a signal SB41 including a command to lower the height of the table 300 by a target change amount TW, the processor 32 generates a control signal SC22 for discharging an amount of oil corresponding to the target change amount TW from the cylinder 21. This control signal SC22 is a pulse signal SP, and the pulse width W of the control signal SC22 represents the time corresponding to the target change amount TW. For example, the pulse width W is 330 ms. This control signal SC22 is supplied to the buffer 33, which performs predetermined processing and then supplies the resulting control signal SC221 to the TFT 35. When the control signal SC221 is supplied, the TFT 35 turns on. When the TFT 35 turns on, a predetermined reference voltage Ref is applied to the valve 29, opening the valve 29. At this time, the TFT 35 maintains the on state for a time corresponding to the pulse width W of 330 ms. Therefore, an amount of oil corresponding to the pulse width W is discharged from the cylinder 21 to the oil tank 24, thereby adjusting the amount of oil in the cylinder 21. Therefore, the cylinder 21 is finely adjusted in the direction of the arrow B, and as a result, the subject support part 303 is lowered by the target change amount TW.

[0045] The table control device 500 also includes a potentiometer 42. The potentiometer 42 outputs an analog signal SE representing a voltage corresponding to the elevation or lowering of the subject support 303 by adjusting the amount of oil in the cylinder 21. The ADC 36 converts the analog signal SE into a digital signal SF and outputs it to the processor 32. The processor 32 calculates the current height of the table 300 based on the button operation by the operator 401 based on the digital signal SF received from the ADC 36. The processor 32 outputs a digital signal SG representing the current height of the table 300 to the converter 31. The converter 31 adjusts the voltage of the digital signal SG received from the processor 32 and sends the voltage-adjusted signal SH to the display unit 16. The signal SH contains information representing the current height of the table 300. Therefore, the display unit 16 displays the current height of the table 300 based on the signal SH. Therefore, the operator 401 can recognize the current height of the table 300 in real time by looking at the display unit 16.

[0046] The table control device 500 is configured as described above. Next, an example of a procedure in this embodiment in which the operator 401 operates the button unit 11 to adjust the height of the table 300 when imaging the subject will be described.

[0047] The operator 401 lies the subject 400 on the table 300 (see FIG. 1), and then adjusts the height of the table 300 .

[0048] First, the operator 401 presses and holds the up button 12 to adjust the table 300 to a height suitable for imaging. While the up button 12 is pressed and held, the table 300 continues to rise, allowing the operator 401 to bring the table 300 closer to the desired height. Furthermore, if the operator 401 has raised the height of the table 300 too much, the operator 401 presses and holds the down button 13. While the down button 13 is pressed and held, the table 300 continues to descend, allowing the operator 401 to quickly lower the height of the table 300 to close to the desired position.

[0049] After roughly positioning the height of the table 300, the operator 401 finely adjusts the height of the table 300. Here, consider a case where the operator 401 wants to finely adjust the table 300 so that the table 300 is lower than its current height.

[0050] In the following, in order to clarify the difference between this embodiment and the conventional method, a conventional method for finely adjusting the height of the table 300 will be described first, and after describing the conventional method, a specific method of this embodiment will be described.

[0051] (1) Conventional method for fine-tuning the table height The following describes a conventional method of table fine-tuning, taking as an example an example in which an operator 401 fine-tunes the table by repeatedly tapping the down button 13 on the operation panel 10. The conventional method of fine-tuning will be described with reference to FIGS. 6 and 7. Note that FIG. 6 shows the block diagram of FIG. 5, but FIG. 5 also includes reference numerals that will not be used in the following description of the table fine-tuning. Therefore, to make the drawing easier to understand, FIG. 6 is a diagram in which unnecessary reference numerals have been removed from FIG. 5. FIG. 7 schematically shows the pulse width W and the amount of descent D of the table 300 corresponding to the tapping operation of the operator 401.

[0052] First, the operator 401 performs a tap operation T1 on the down button 13 so that the table 300 is lowered by a predetermined target change amount. The tap operation T1 is shown in FIG. 7. When the tap operation T1 is executed, as shown in FIG. 6, an operation signal SB4 for lowering the table 300 by the target change amount TW (see FIG. 4) is output from the operation panel 10 and input to the converter 31. Upon receiving the operation signal SB4, the converter 31 converts the voltage of the operation signal SB4 and outputs a voltage-converted signal SB41. The voltage-converted signal SB41 is a signal including a command for lowering the height of the table 300 by the target change amount TW.

[0053] When the processor 32 receives from the converter 31 a signal SB41 including a command to lower the height of the table 300 by the target change amount TW, the processor 32 generates a control signal SC22 to discharge an amount of oil corresponding to the target change amount TW from the cylinder 21. This control signal SC22 is a pulse signal SP, and the pulse width W of the control signal SC22 is a fixed value. While FIG. 7 shows an example in which the pulse width W is 330 ms, W may be a value other than 330 ms. The control signal SC22 including the pulse width W (=330 ms) is supplied to the buffer 34, which then performs predetermined processing and supplies the resulting control signal SC221 to the TFT 35. When the control signal SC221 is supplied, the TFT 35 is turned on. When the TFT 35 is turned on, a predetermined reference voltage Ref is applied to the valve 29, opening the valve 29. At this time, the TFT 35 maintains the on state for a period of time corresponding to the pulse width W (=330 ms). Therefore, an amount of oil corresponding to the pulse width W is discharged from the cylinder 21 into the oil tank 24. This causes the cylinder 21 to be finely adjusted in the direction of the arrow B, resulting in the table 300 descending. Figure 7 shows the amount of descending D of the table 300 corresponding to operation T1. Here, the target change amount TW of the amount of descending D of the table 300 is 0.5 mm, and the operation T1 causes the amount of descending D to match the target change amount TW.

[0054] Similarly, each time a tap operation T2, T3, T4, . . . is executed, the table 300 can be lowered by 0.5 mm.

[0055] However, depending on the environment in which the gantry is used, the amount of lowering D of the table 300 may deviate from the target amount of change TW (see FIG. 8).

[0056] FIG. 8 is an explanatory diagram showing a case where the amount of lowering D of the table 300 deviates from the target amount of change TW. In Fig. 8, when the operator 401 performs a tap operation T1 on the down button 13 (an operation to lower the table 300 by the target change amount TW), the processor 32 outputs a control signal with a pulse width W (=330 ms) as described in Fig. 7. The pulse width W = 330 ms ideally represents a pulse width that lowers the table 300 by the target change amount TW (for example, 0.5 mm).

[0057] However, in FIG. 8, the table 300 is lowered by a value (e.g., 0.7 mm) that deviates from the target change amount TW. In this way, the amount of lowering D of the table 300 may not match the target change amount TW due to the influence of the environment in which the table is used. Similarly, the operator 401 continues operations T2, T3, T4, etc., but the amount of lowering D does not match the target change amount TW. Therefore, ideally, operations T1 to T4 should be operations that lower the height of the table 300 by the target change amount TW. However, in reality, even when operations T1 to T4 are performed, the amount of lowering D of the table 300 deviates from the target change amount TW. Therefore, it takes time for the operator 401 to align the table 300 to the desired height, which increases the workload of the operator 401.

[0058] Therefore, the inventors of the present application have conducted extensive research and have devised a method for making the deviation DM between the actual amount of lowering D and the target amount of change TW zero (or approaching zero) as quickly as possible, even if the actual amount of lowering D of the table 300 deviates from the target amount of change TW during fine adjustment of the height of the table 300. The method for finely adjusting the height of the table 300 in this embodiment will be described below.

[0059] (2) How to fine-tune the height of the table in this embodiment The method for fine-tuning the table in this embodiment will be described with reference to FIG.

[0060] FIG. 9 is a diagram showing the operation flow of the table 300 when finely adjusting the height of the table 300 according to this embodiment. 9 will be explained with reference to Fig. 6 and Fig. 10 as necessary. Fig. 6 is a block diagram of table control device 500, and Fig. 10 shows pulse width W and amount of lowering D of table 300 corresponding to the operation of operator 401.

[0061] In step ST1, the processor 32 waits for a tap operation T1 (see FIG. 10) to be performed on the down button 13. When the operator 401 performs the tap operation T1 on the down button 13, the process proceeds to step ST2.

[0062] In step ST2, as shown in FIG. 6, an operation signal SB4 for lowering the height of the table 300 by a target change amount TW is output from the operation panel 10 and input to the converter 31. Here, the target change amount TW is assumed to be 0.5 mm. However, TW can be set to a value smaller than 0.5 mm, e.g., 0.1 mm. Upon receiving the operation signal SB4, the converter 31 converts the voltage of the operation signal SB4 and outputs a voltage-converted signal SB41. The voltage-converted signal SB41 contains a command for lowering the height of the table 300 by the target change amount TW. The processor 32 receives the signal SB41 containing a command for lowering the height of the table 300 by the target change amount TW from the converter 31 and generates a control signal SC22 having a pulse width W=W1 based on the signal SB41. This control signal SC22 is a pulse signal SP. The pulse width W1 corresponding to the operation T1 is 330 ms, as shown in FIG. 10. After the control signal SC22 is generated, the process proceeds to step ST3.

[0063] In step ST3, the height of the table 300 is finely adjusted based on the control signal SC22. Specifically, the height of the table 300 is finely adjusted as follows. As shown in FIG. 6, the control signal SC22 is supplied to the buffer 34, which then performs predetermined processing on the control signal SC221, which is then supplied to the TFT 35. When the control signal SC221 is supplied, the TFT 35 is turned on. When the TFT 35 is turned on, a predetermined reference voltage Ref is applied to the valve 29, and the valve 29 opens. At this time, the TFT 35 maintains the on state for a period of time corresponding to the pulse width W1 (=330 ms). Therefore, an amount of oil corresponding to the pulse width W1 is discharged from the cylinder 21 to the oil tank 24. As a result, the cylinder 21 moves in the direction of arrow B, and the subject support member 303 descends, resulting in fine adjustment of the height of the table 300.

[0064] In step ST4, the height of the table 300 is displayed. Specifically, the height of the table 300 is displayed as follows.

[0065] The potentiometer 42 outputs an analog signal SE representing a voltage corresponding to the lowering of the subject support member 303 as a result of adjusting the amount of oil in the cylinder 21. The ADC 36 converts the analog signal SE into a digital signal SF and outputs it to the processor 32. The processor 32 calculates the current height of the table 300 corresponding to the operation T1 of the operator 401 based on the digital signal SF received from the ADC 36. The processor 32 outputs a digital signal SG representing the current height of the table 300 to the converter 31. The converter 31 adjusts the voltage of the digital signal SG received from the processor 32 and sends the voltage-adjusted signal SH to the display unit 16. The signal SH contains information representing the current height of the table 300. Therefore, the display unit 16 can display the current height of the table 300 based on the signal SH. Therefore, the operator 401 can recognize the current height of the table 300 in real time by looking at the display unit 16.

[0066] In step ST5, the processor 32 calculates the actual lowering amount D of the table 300 based on the digital signal SE received from the ADC 36. Fig. 10 shows the lowering amount D = D1 of the table 300 corresponding to the operation T1. Here, D1 = 1.0 mm. After calculating the lowering amount D = D1 (= 1.0 mm), the process proceeds to step ST6.

[0067] In step ST6, processor 32 uses the pulse width W1 used in tapping operation T1 to calculate a pulse width W2 to be used when lowering the table in the next tapping operation T2. ​​This pulse width W2 is calculated using the following equation (1). W2=W1-W1*K*DM (1) Where W2 is the pulse width used in the next operation T2, W1 is the pulse width used in operation T1, K: Gain, DM: Deviation calculated in operation T1

[0068] Therefore, it can be seen that the pulse width W2 is a value that depends on the gain K. The gain K is a value that is determined based on the deviation amount DM. A method for calculating the pulse width W2 using equation (1) will be described below with reference to FIG.

[0069] FIG. 11 is a flow diagram of a method for calculating the pulse width W2 in step ST6. In step ST61, the processor 32 calculates a deviation amount DM, which is the difference between the amount of descent D calculated in step ST5 and the target amount of change TW. The deviation amount DM is expressed by the following equation (2).

[0070] DM=D1-TW (2) Here, D1: the amount of descent when operation T1 is performed, TW: the target amount of change

[0071] In this embodiment, the target change amount TW is 0.5 mm. The lowering amount D1 due to the operation T1 is 1.0 mm. Therefore, the deviation amount DM is expressed by the following equation (3).

[0072] DM=D1-TW =1.0-0.5 =0.5(mm) (3) After calculating the deviation amount DM, the process proceeds to step ST62.

[0073] In step ST62, the processor 32 determines the value of the gain K based on the deviation amount DM. In this embodiment, the gain K is determined based on the following three conditions (4) to (6). DM>0.15 : K=0.5 (4) 0.15≧DM≧-0.05 : K=0.8 (5) -0.05>DM : K=1.8 (6)

[0074] That is, if DM>0.15, the processor 32 determines the gain K to be K=0.5; if 0.15≧DM≧−0.05, the processor 32 determines K=0.8; and if −0.05>DM, the processor 32 determines K=1.8. Here, DM is calculated as DM=0.5 mm as shown in equation (3). Therefore, since DM satisfies condition (4), the processor 32 determines the gain K to be K=0.5. Note that in this embodiment, the gain K is determined based on three conditions, but the gain K may be determined based on two conditions, or may be determined based on four or more conditions. After determining the gain K, the processor 32 proceeds to step ST63.

[0075] In step ST63, the pulse width W2 is calculated based on equation (1). It can be seen from FIG. 10 that W1 = 330 ms. The gain K is determined to be K = 0.5 in step ST62. Furthermore, the deviation amount DM is DM = 0.5 mm from equation (3). Therefore, by substituting these values ​​into equation (1), the pulse width W2 can be calculated as follows:

[0076] W2=W1-W1*K*DM =330ms-330ms*0.5*0.5 =247.5ms (7)

[0077] Therefore, in operation T1, pulse width W1 = 330 ms was used, but by the processing of step ST6, pulse width W2 corresponding to the next operation T2 is calculated as W2 = 247.5 ms. The calculated pulse width W2 (= 247.5 mm) is shown in Figure 10. After calculating pulse width W2, proceed to step ST7.

[0078] In step ST7, processor 32 determines whether table 300 has reached the target height. If table 300 has reached the target height, the flow ends. On the other hand, if table 300 has not reached the target height, the flow returns to step ST1. Here, it is assumed that table 300 has not reached the target height. Therefore, the flow returns to step ST1.

[0079] In step ST1, the processor 32 waits for a tap operation T2 (see FIG. 10) to be performed on the down button 13. When the operator 401 performs the tap operation T2 on the down button 13, the process proceeds to step ST2.

[0080] In step ST2, as shown in FIG. 6, an operation signal SB4 for lowering the height of the table 300 by a target change amount TW is output from the operation panel 10 and input to the converter 31. Upon receiving the operation signal SB4, the converter 31 converts the voltage of the operation signal SB4 and outputs a voltage-converted signal SB41. The processor 32 generates a control signal SC22 including a pulse width W=W2 expressed by equation (7) based on the signal SB41 from the converter 31. FIG. 10 shows that the pulse width W2 (=247.5 ms) calculated by equation (7) is used as the pulse width W when the tap operation T2 is performed. After the control signal SC22 including the pulse width W (=W2) is generated, the process proceeds to step ST3.

[0081] In step ST3, the height of the table 300 is finely adjusted based on the control signal SC22. Specifically, as shown in FIG. 6, the control signal SC22 is supplied to the buffer 34, and the buffer 34 performs predetermined processing and then supplies the control signal SC221 to the TFT 35. When the control signal SC221 is supplied, the TFT 35 is turned on, and the valve 29 opens. At this time, the TFT 35 maintains the on state for a period of time corresponding to the pulse width W2 (=247.5 ms). Therefore, an amount of oil corresponding to the pulse width W2 is discharged from the cylinder 21 to the oil tank 24. As a result, the cylinder 21 moves in the direction of arrow B, and the subject support part 303 descends, resulting in fine adjustment of the height of the table 300.

[0082] In step ST4, the current height of the table 300 corresponding to the operation T2 is displayed on the display unit 16 based on the analog signal SE from the potentiometer 42. Once the current height of the table 300 is displayed, the process proceeds to step ST5.

[0083] In step ST5, the processor 32 calculates the actual lowering amount D of the table 300 based on the digital signal SE received from the ADC 36. Fig. 10 shows the lowering amount D = D2 of the table 300 corresponding to the operation T2. ​​Here, D2 = 0.55 mm. After calculating the lowering amount D = D2 (= 0.55 mm), the process proceeds to step ST6.

[0084] In step ST6, processor 32 uses pulse width W2 used in tapping operation T2 to calculate pulse width W3 to be used when lowering the table in the next tapping operation T3. This pulse width W3 is calculated using the following equation (8). W3=W2-W2*K*DM (8) Where W3 is the pulse width used in the next operation T3, W2 is the pulse width used in operation T2, K: Gain, DM: Deviation calculated in operation T2

[0085] When calculating the pulse width W3 using equation (8), the pulse width W3 can be calculated in the same manner as the pulse width W2 according to the flow shown in Fig. 11. Therefore, a method for calculating the pulse width W3 will be described with reference to Fig. 11.

[0086] In step ST61, the processor 32 calculates a deviation amount DM, which is the difference between the amount of descent D calculated in step ST5 and the target amount of change TW. The deviation amount DM is expressed by the following equation (9).

[0087] DM=D2-TW (9) Here, D2 is the amount of descent when operation T2 is performed, and TW is the target amount of change.

[0088] In this embodiment, the target change amount TW is 0.5 mm. The lowering amount D2 due to the operation T2 is D2=0.55 mm. Therefore, the deviation amount DM is expressed by the following equation (10).

[0089] DM=D2-TW =0.55-0.5 =0.05(mm) (10) After calculating the deviation amount DM, the process proceeds to step ST62.

[0090] In step ST62, the processor 32 determines the value of the gain K based on the deviation amount DM. In this embodiment, as described above, the gain K is determined based on the following three conditions (4) to (6). DM>0.15 : K=0.5 (4) 0.15≧DM≧-0.05 : K=0.8 (5) -0.05>DM : K=1.8 (6)

[0091] Here, DM is calculated as DM=0.05 mm as shown in equation (10). Therefore, DM satisfies condition (5), and therefore, processor 32 determines that gain K is K=0.8. After determining gain K, the process proceeds to step ST63.

[0092] In step ST63, the pulse width W3 is calculated based on equation (8). From equation (7), it is found that W2 = 247.5 ms. Furthermore, the gain K is determined to be K = 0.8 in step ST62. Furthermore, from equation (10), the deviation amount DM is DM = 0.05 mm. Therefore, by substituting these values ​​into equation (8), the pulse width W3 can be calculated as follows:

[0093] W3=W2-W2*K*DM =247.5ms-247.5ms*0.8*0.05 =237.6ms (11)

[0094] Therefore, in operation T2, pulse width W2 = 247.5 ms was used, but by the processing of step ST6, pulse width W3 corresponding to the next operation T3 is calculated as W3 = 237.6 ms. The calculated pulse width W3 (= 237.6 mm) is shown in Figure 10. After calculating pulse width W3, proceed to step ST7.

[0095] In step ST7, the processor 32 determines whether the table 300 has reached the target height. Here, it is assumed that the table 300 has not reached the target height. Therefore, the process returns to step ST1.

[0096] In step ST1, the processor 32 waits for a tap operation T3 (see FIG. 10) to be performed on the down button 13. When the operator 401 performs the tap operation T3 on the down button 13, the process proceeds to step ST2.

[0097] In step ST2, as shown in FIG. 6, an operation signal SB4 for lowering the height of the table 300 by a target change amount TW is output from the operation panel 10 and input to the converter 31. Upon receiving the operation signal SB4, the converter 31 converts the voltage of the operation signal SB4 and outputs a voltage-converted signal SB41. The processor 32 generates a control signal SC22 including a pulse width W=W3 expressed by equation (11) based on the signal SB41 from the converter 31. FIG. 10 shows that a pulse width W3 (=237.6 ms) is used as the pulse width W when a tap operation T3 is performed. After the control signal SC22 including the pulse width W (=W3) is generated, the process proceeds to step ST3.

[0098] In step ST3, the height of the table 300 is finely adjusted based on the control signal SC22. Specifically, as shown in FIG. 6, the control signal SC22 is supplied to the buffer 34, and the buffer 34 performs predetermined processing and then supplies the control signal SC221 to the TFT 35. When the control signal SC221 is supplied, the TFT 35 is turned on, and the valve 29 opens. At this time, the TFT 35 maintains the on state for a period of time corresponding to the pulse width W3 (=237.6 ms). Therefore, an amount of oil corresponding to the pulse width W3 is discharged from the cylinder 21 to the oil tank 24. As a result, the cylinder 21 moves in the direction of arrow B, and the subject support part 303 descends, resulting in fine adjustment of the height of the table 300.

[0099] In step ST4, the current height of the table 300 corresponding to the operation T3 is displayed on the display unit 16 based on the analog signal SE from the potentiometer 42. Once the current height of the table 300 is displayed, the process proceeds to step ST5.

[0100] In step ST5, the processor 32 calculates the actual lowering amount D of the table 300 based on the digital signal SE received from the ADC 36. Fig. 10 shows the lowering amount D = D3 of the table 300 corresponding to the operation T3. Here, D3 = 0.5 mm. After calculating the lowering amount D = D3 (= 0.5 mm), the process proceeds to step ST6.

[0101] In step ST6, processor 32 uses pulse width W3 used in tapping operation T3 to calculate pulse width W4 to be used when lowering the table in the next tapping operation T4. This pulse width W4 is calculated using the following equation (12). W4=W3-W3*K*DM (12) Where W4 is the pulse width used in the next operation T4, W3 is the pulse width used in operation T3, K: Gain, DM: Deviation calculated in operation T3

[0102] When calculating the pulse width W4 using equation (12), the pulse width W4 can be calculated in the same manner as the pulse widths W2 and W3 according to the flow shown in Fig. 11. Therefore, a method for calculating the pulse width W4 will be described with reference to Fig. 11.

[0103] In step ST61, the processor 32 calculates a deviation amount DM, which is the difference between the amount of descent D calculated in step ST5 and the target amount of change TW. The deviation amount DM is expressed by the following equation (13).

[0104] DM=D3-TW (13) Here, D3 is the amount of descent when operation T3 is performed, and TW is the target amount of change.

[0105] In this embodiment, the target change amount TW is 0.5 mm. The lowering amount D3 due to the operation T3 is 0.5 mm. Therefore, the deviation amount DM is expressed by the following equation (14).

[0106] DM=D3-TW =0.5-0.5 =0(mm) (14) After calculating the deviation amount DM, the process proceeds to step ST62.

[0107] In step ST62, the processor 32 determines the value of the gain K based on the deviation amount DM. In this embodiment, as described above, the gain K is determined based on the following three conditions (4) to (6). DM>0.15 : K=0.5 (4) 0.15≧DM≧-0.05 : K=0.8 (5) -0.05>DM : K=1.8 (6)

[0108] Here, DM is calculated as DM=0 mm as shown in equation (14). Therefore, DM satisfies condition (5), and therefore, processor 32 determines that gain K is K=0.8. After determining gain K, the process proceeds to step ST63.

[0109] In step ST63, the pulse width W4 is calculated based on equation (12). From equation (11), it is found that W3 = 237.6 ms. Furthermore, the gain K is determined to be K = 0.8 in step ST62. Furthermore, from equation (14), the deviation amount DM is DM = 0 mm. Therefore, by substituting these values ​​into equation (12), the pulse width W4 can be calculated as follows:

[0110] W4=W3-W3*K*DM =237.6ms-237.6ms*0.8*0 =237.6ms (15)

[0111] Therefore, the pulse width W4 corresponding to the next operation T4 is calculated as W4 = 237.6 ms. The calculated pulse width W4 (= 237.6 mm) is shown in Figure 10. After calculating the pulse width W4, proceed to step ST7.

[0112] In step ST7, the processor 32 determines whether the table 300 has reached the target height. Here, it is assumed that the table 300 has not reached the target height. Therefore, the process returns to step ST1.

[0113] In step ST1, the processor 32 waits for a tap operation T4 (see FIG. 10) to be performed on the down button 13. When the operator 401 performs the tap operation T4 on the down button 13, the process proceeds to step ST2.

[0114] In step ST2, as shown in FIG. 6, an operation signal SB4 for lowering the height of the table 300 by a target change amount TW is output from the operation panel 10 and input to the converter 31. Upon receiving the operation signal SB4, the converter 31 converts the voltage of the operation signal SB4 and outputs a voltage-converted signal SB41. The processor 32 generates a control signal SC22 including a pulse width W=W4 expressed by equation (15) based on the signal SB41 from the converter 31. FIG. 10 shows that a pulse width W4 (=237.6 ms) is used as the pulse width W when a tap operation T4 is performed. After the control signal SC22 including the pulse width W (=W4) is generated, the process proceeds to step ST3.

[0115] In step ST3, the height of the table 300 is finely adjusted based on the control signal SC22. Specifically, as shown in FIG. 6, the control signal SC22 is supplied to the buffer 34, and the buffer 34 performs predetermined processing and then supplies the control signal SC221 to the TFT 35. When the control signal SC221 is supplied, the TFT 35 is turned on, and the valve 29 opens. At this time, the TFT 35 maintains the on state for a period of time corresponding to the pulse width W4 (=237.6 ms). Therefore, an amount of oil corresponding to the pulse width W2 is discharged from the cylinder 21 to the oil tank 24. As a result, the cylinder 21 moves in the direction of arrow B, and the subject support part 303 descends, resulting in fine adjustment of the height of the table 300.

[0116] In step ST4, the current height of the table 300 corresponding to operation T4 is displayed on the display unit 16 based on the analog signal SE from the potentiometer 42. Once the current height of the table 300 is displayed, the process proceeds to step ST5.

[0117] In step ST5, the processor 32 calculates the actual lowering amount D of the table 300 based on the digital signal SE received from the ADC 36. Fig. 10 shows the lowering amount D = D4 of the table 300 corresponding to the operation T3. Here, D4 ​​= 0.5 mm. After calculating the lowering amount D = D4 (= 0.5 mm), the process proceeds to step ST6.

[0118] In step ST6, processor 32 uses pulse width W4 used in tapping operation T4 to calculate pulse width W5 to be used when lowering the table in the next tapping operation T5. This pulse width W5 is calculated using the following equation (16). W5=W4-W4*K*DM (16) Where W5 is the pulse width used in the next operation T5, W4 is the pulse width used in operation T4, K: Gain, DM: Deviation calculated in operation T4

[0119] When calculating the pulse width W5 using equation (16), the pulse width W5 can be calculated in the same manner as the pulse widths W2 to W4 according to the flow shown in Fig. 11. Therefore, a method for calculating the pulse width W5 will be described with reference to Fig. 11.

[0120] In step ST61, the processor 32 calculates a deviation amount DM, which is the difference between the amount of descent D calculated in step ST5 and the target amount of change TW. The deviation amount DM is expressed by the following equation (17).

[0121] DM=D4-TW (17) Here, D4 ​​is the amount of descent when operation T4 is executed, and TW is the target amount of change.

[0122] In this embodiment, the target change amount TW is 0.5 mm. The lowering amount D4 due to the operation T4 is D4=0.5 mm. Therefore, the deviation amount DM is expressed by the following equation (18).

[0123] DM=D4-TW =0.5-0.5 =0(mm) (18) After calculating the deviation amount DM, the process proceeds to step ST62.

[0124] In step ST62, the processor 32 determines the value of the gain K based on the deviation amount DM. In this embodiment, as described above, the gain K is determined based on the following three conditions (4) to (6). DM>0.15 : K=0.5 (4) 0.15≧DM≧-0.05 : K=0.8 (5) -0.05>DM : K=1.8 (6)

[0125] Here, DM is calculated as DM=0 mm as shown in equation (18). Therefore, DM satisfies condition (5), and therefore, processor 32 determines that gain K is K=0.8. After determining gain K, the process proceeds to step ST63.

[0126] In step ST63, the pulse width W5 is calculated based on equation (16). From equation (15), it is found that W4 = 237.6 ms. Furthermore, the gain K is determined to be K = 0.8 in step ST62. Furthermore, from equation (18), the deviation amount DM is DM = 0 mm. Therefore, by substituting these values ​​into equation (16), the pulse width W5 can be calculated as follows:

[0127] W5=W4-W4*K*DM =237.6ms-237.6ms*0.8*0 =237.6ms (19)

[0128] Therefore, the pulse width W5 corresponding to the next operation T5 is calculated as W5=237.6 ms.

[0129] Similarly, each time a tapping operation is performed to lower the height of the table 300, the pulse width to be used in the next tapping operation is calculated. In the above explanation, an example of calculating pulse widths W2, W3, W4, and W5 was explained. However, the pulse widths to be calculated may be "W i+1 ” is the pulse width W i+1 can be calculated using the following equation (20). W i+1 =W i -W i *K*DM (20) where W i+1 :Next operationT i+1 The pulse width, W, used in i :Operation T i The pulse width used in K: Gain, DM: Operation T i The deviation calculated by

[0130] For example, operation T p If executed, the next operation T p+1 The pulse width W used p+1 is calculated by substituting i=p for i in equation (20) as follows: W p+1 =W p -W p *K*DM (21) where W p+1 :Next operationT p+1 The pulse width, W, used in p :Operation T p The pulse width used in K: Gain, DM: Operation T p The deviation calculated by

[0131] Therefore, each time an operation is performed, the pulse width W is set based on equation (20) to make the table descend amount match the target change amount (or approach the target change amount). i+1 Then, when it is determined in step ST7 that the table 300 has reached the target height, the flow ends.

[0132] In this embodiment, when fine-adjusting the height of the table 300, the operator 401 performs the fine-adjustment operation of the table 300 using the buttons on the operation panel 10. When the operator 401 performs the fine-adjustment operation to lower the height of the table 300 by the target change amount, the height of the table 300 is fine-adjusted to be lowered in accordance with the operation of the operator 401. Meanwhile, the processor 32 adjusts the pulse width based on the deviation DM between the actual lowering amount D of the table 300 and the target change amount TW. In this embodiment, the value of the gain K is determined according to the value of the deviation DM, so it is possible to calculate the pulse width for making the deviation DM zero (or reducing it). Then, when the operator 401 performs the next operation, the height of the table 300 is fine-adjusted based on the calculated pulse width. Therefore, even if the amount of descent D of table 300 differs from the target change amount TW when fine adjustment of the height of table 300 is initially started, by calculating the pulse width based on the deviation amount DM as described above, the amount of descent D of table 300 can be made to approach the target change amount TW and ultimately match the amount of descent D with the target change amount TW. Once the amount of descent D matches the target change amount TW, the amount of descent D stabilizes, and thereafter the amount of descent D of table 300 can be made to (substantially) match the target change amount TW. Therefore, the actual amount of descent D stabilizes in response to the operation of operator 401, and the workload of operator 401 in adjusting the height of table 300 can be reduced.

[0133] In the flow shown in FIG. 9 executed in this embodiment, the value of gain K is determined based on the deviation amount DM and the pulse width is calculated (see step ST). However, for reference, FIG. 12 shows a flow in which the pulse width is set to a fixed value. Because the pulse width is a fixed value in the flow shown in FIG. 12, step ST5, which calculates the amount of decrease required to calculate the pulse width, and step ST6, which calculates the pulse width, are not included. Therefore, the pulse width cannot be set to an optimal value. As a result, as shown in FIG. 8, the amount of decrease of the table 300 cannot be matched to the target change amount. In contrast, in this embodiment, steps ST5 and ST6 are included. Therefore, even if the amount of decrease of the table does not match the target change amount, the value of gain K is determined based on the deviation amount DM and the pulse width is calculated, so the amount of decrease of the table 300 can be quickly (substantially) matched to the target change amount TW.

[0134] In order to clarify the effect of this embodiment, the relationship between the number of tap operations and the amount of movement of the table height was calculated, and the calculation results are shown in FIG.

[0135] 13 shows graphs 91, 92, and 93. Graphs 91 to 93 show the relationship between the number of tapping operations and the amount of movement of the table height when the initial value of the amount of movement of the table is 0.2 (mm), 0.3 (mm), 0.4 (mm), 0.5 (mm), 0.6 (mm), 0.7 (mm), 0.8 (mm), 0.9 (mm), and 1.0 (mm).

[0136] Graph 91 shows the relationship between the number of tap operations and the amount of movement of the table height when the pulse width is fixed. When the pulse width is fixed, it can be seen that the amount of movement does not change from the initial value no matter how many times the tap operation is repeated.

[0137] Graph 92 shows the relationship between the number of tapping operations and the amount of movement of the table height when proportional control with a fixed gain K is used. When proportional control with a fixed gain K is used, the amount of movement converges from the initial value to the target movement amount of 0.5 mm by repeatedly performing tapping operations, but it takes 4 to 5 tapping operations to reach convergence.

[0138] Graph 93 shows the relationship between the number of tapping operations and the amount of movement of the table height when the method of this embodiment is used, which determines the gain K based on the amount of deviation DM. When the method of this embodiment is used, it can be seen that by repeatedly performing tapping operations three times, the amount of movement converges from the initial value to the target amount of movement of 0.5 mm.

[0139] Therefore, it can be seen from graphs 91 to 93 that by adopting the method of this embodiment, even if the amount of lowering of the table does not match the target change amount, the amount of lowering of the table 300 quickly matches (substantially) the target change amount TW.

[0140] In FIG. 10, operations T1 to T2 are performed to finely adjust the height of the table 300 so that the table 300 is lowered by a lowering amount D. p+1 However, the operations T1 to T p+1 In between, another operation may be performed to adjust the height of the table (see FIG. 14).

[0141] FIG. 14 is a diagram showing an example in which another operation for adjusting the height of the table is performed between operations T1 and T5. Figure 14 shows an example in which an operation U11 is performed between operations T1 and T2 to continuously lower the table 300, and an operation U12 is performed between operations T3 and T4 to raise the table 300 by the target change amount TV (see Figure 3).

[0142] In this way, even if other operations U11 and U12 are performed between operations T1 to T5, the pulse widths W2 to W5 can be calculated by focusing only on operations T1 to T5, calculating the deviation amount DM for operations T1 to T5 in the procedure described above, and determining the value of gain K based on the deviation amount DM. Therefore, the amount of decrease D can be quickly matched with the target amount of change TW.

[0143] In the first embodiment, an example is described in which the amount of descent D of the table 300 is made to coincide with the target amount of change TW (see FIG. 4), but the present invention can also be applied to a case in which the amount of ascent of the table 300 is made to coincide with the target amount of change TV (see FIG. 3). When raising the table 300, the deviation DM between the amount of ascent of the table and the target amount of change TV is calculated, and the value of the gain K is determined based on this deviation DM, thereby making it possible to calculate the pulse width for making the amount of ascent of the table coincide with (or approach) the target amount of change TV.

[0144] (2) Second embodiment In the second embodiment, a case will be described in which the CT system has a function for adjusting the tilt angle of the gantry 200.

[0145] FIG. 15 is a block diagram of the gantry 200 and a gantry control device 600 that controls the tilt angle of the main body of the gantry.

[0146] The gantry control device 600 of the second embodiment is basically the same as the table control device 500 described in the first embodiment. Therefore, in describing the second embodiment, differences from the first embodiment will be mainly described.

[0147] The gantry control device 600 has a hydraulic device 20. The hydraulic device 20 includes a unit 23 of a cylinder 21 and a piston 22, an oil tank 24, a supply pipe 25, a discharge pipe 26, and an oil amount adjuster 27. The hydraulic device 20 is housed inside the gantry 200, but in FIG. 15 , to make the components of the hydraulic device 20 easier to see, the components other than the unit 23 are illustrated outside the gantry 200. When the cylinder 21 moves toward the piston 22 in the direction of arrow B, the gantry 200 tilts toward the rear side 52 around the rotation axis 57. On the other hand, when the cylinder 21 moves in the direction of arrow A relative to the piston 22, the gantry 200 tilts toward the front side 51 around the rotation axis 57. The structures of the unit 23, oil tank 24, supply pipe 25, discharge pipe 26, and oil volume adjustment section 27 of the hydraulic device 20 are the same as those of the hydraulic device described in the first embodiment, so explanations that overlap with the first embodiment will be omitted.

[0148] The gantry control device 600 also includes an operation panel 10 and a control board 330. The structure of the operation panel 10 is the same as that of the operation panel 10 described in the first embodiment. The control board 330 of the second embodiment also includes a relay 43, which supplies an AC signal from an AC source 41 to the pump 28, but the other configurations are the same as those of the control board 30 of the first embodiment.

[0149] FIG. 16 is an explanatory diagram of the operation panel 10 in the second embodiment. In FIG. 16, only the parts related to the operation of the CT system of the second embodiment will be described with reference numerals.

[0150] The operation panel 10 includes a forward tilt button 14 and a backward tilt button 15 for tilting the gantry 200. The forward tilt button 14 is a button for tilting the gantry 200 toward the front side 51, and the backward tilt button 15 is a button for tilting the gantry 200 toward the rear side 52.

[0151] When operator 401 wants to roughly adjust the tilt angle of gantry 200, operator 401 presses and holds forward tilt button 14 or backward tilt button 15. For example, when operator 401 wants to continuously tilt gantry 200 to the front side 51, operator 401 presses and holds forward tilt button 14. When forward tilt button 14 is pressed and held by operator 401, gantry 200 continuously tilts to the front side 51 while forward tilt button 14 is being pressed and held by operator 401. On the other hand, when operator 401 wants to continuously tilt gantry 200 to the rear side 52, operator 401 presses and holds backward tilt button 15. When backward tilt button 15 is pressed and held by operator 401, gantry 200 continuously tilts to the rear side 52 while backward tilt button 15 is being pressed and held by operator 401.

[0152] Furthermore, when operator 401 wishes to fine-tune the tilt angle of gantry 200, operator 401 performs a tap operation by pressing forward tilt button 14 or backward tilt button 15 and immediately releasing his / her hand from button 14 or 15. FIG. 17 is an explanatory diagram of the case where forward tilt button 14 is tapped. In FIG. 17, gantry 200 before the tap operation is shown by a dashed line, and gantry 200 after the tap operation is shown by a solid line. The tilt angle of gantry 200 changes from tilt angle 53 to tilt angle 54 with a single tap operation. In other words, gantry 200 is set so that the tilt angle changes toward front side 51 by target change amount TA with a single tap operation. In FIG. 17, target change amount TA is exaggerated to make it easier to understand, but in reality, target change amount TA is a value of approximately TA = 0.1 (degrees) to 0.5 (degrees). Therefore, the operator 401 can finely control the tilt angle of the gantry 200 by tapping the forward tilt button 14.

[0153] On the other hand, FIG. 18 is an explanatory diagram of the case where backward tilt button 15 is tapped. In FIG. 18, gantry 200 before the tapping operation is indicated by a dashed line, and gantry 200 after the tapping operation is indicated by a solid line. The tilt angle of gantry 200 changes from tilt angle 55 to tilt angle 56 with a single tapping operation. In other words, gantry 200 is set so that the tilt angle changes toward rear side 52 by target change amount TB with a single tapping operation. In FIG. 18, target change amount TB is exaggerated to make it easier to understand, but in reality, target change amount TB is a value of approximately TB = 0.1 (degrees) to 0.5 (degrees). Therefore, operator 401 can finely control the tilt angle of gantry 200 by tapping backward tilt button 15.

[0154] The target change amount TA when tilting the gantry 200 toward the front side 51 is the same as the target change amount TB when tilting the gantry 200 toward the rear side 52 (i.e., TA=TB). However, it is also possible for TA≠TB. Returning to FIG. 16, the explanation will be continued.

[0155] The display unit 16 of the operation panel 10 includes a display area 18. The display area 18 is an area that displays the current tilt angle of the gantry.

[0156] Therefore, by tapping the forward tilt button 14 or the backward tilt button 15, the operator 401 can adjust the tilt angle of the gantry 200 while checking the current tilt angle of the gantry 200 on the display unit 16.

[0157] Furthermore, the gantry control device 600 includes a potentiometer 42. The potentiometer 42 measures the tilt angle of the gantry 200.

[0158] Gantry control device 600 is configured as described above. When operator 401 performs an operation to fine-tune the tilt angle of gantry 200, ideally, the tilt angle of gantry 200 changes by a target change amount TA or TB (e.g., 0.5 degrees). However, depending on the environment in which gantry 200 is used (such as the temperature and humidity in the scan room), the actual change amount of the tilt angle of gantry 200 may deviate from the target change amount TA or TB.

[0159] In this way, even if the gantry tilt angle does not match the target change amount TA or TB, as described in the first embodiment, by adjusting the gain K based on the deviation amount DM, it is possible to calculate a pulse width that can make the deviation amount DM zero (or approach zero).

[0160] Although the first and second embodiments use a CT system as an example of a medical device, the present invention is not limited to CT systems and can be applied to any medical device that requires adjustment of the movement of a movable body using a cylinder and a piston (for example, an MRI device, a PET-CT device, a PET-MRI device, a radiation therapy device, etc.). [Explanation of symbols]

[0161] 10 Operation panel 11 Button section 12 Up button 13 Down button 14 Forward tilt button 15 Backward tilt button 16 Display 17 Display area 18 Display area 20 Hydraulic system 21 cylinders 22 Piston 23 units 24 Oil Tank 25 Supply pipe 26 Discharge pipe 27 Oil amount adjustment section 28 Pump 29 Valve 30 Control Board 31 Converter 32 processors 33 buffers 34 buffers 35 TFT 36 ADC 37 Storage device 40 inverter 41 AC source 42 Potentiometer 43 Relay 51 Front side 52 rear side 53~56 Inclination angle 57 Rotation axis 91~93 graph 100 CT System 200 Gantry 201 Bore 300 tables 301 Base 302 Legs 303 Subject support unit 330 control board 400 subjects 401 Operator 500 Table control device 600 Gantry control device

Claims

1. a unit including a cylinder and a piston, at least a portion of the piston being disposed within the cylinder, and configured such that an amount of working fluid within the cylinder is adjusted to move one of the cylinder and the piston relative to the other; a movable body that moves in response to the relative movement of the cylinder and the piston; a control unit that generates, based on a first operation signal input by a user's operation for moving the movable body by a target change amount, a control signal including a first pulse width corresponding to the target change amount so that the movable body moves by the target change amount; a fluid amount adjusting unit that adjusts the amount of working fluid contained in the cylinder based on the first pulse width; Including, The control unit determining the amount of movement of the movable body by adjusting the amount of working fluid in the cylinder; determining a gain value based on a deviation between the movement amount of the movable body and the target change amount; calculating a second pulse width based on the deviation amount and the determined gain value; generating a control signal including the second pulse width when a second operation signal for moving the movable body by a target change amount is input after the first operation signal; Run The fluid amount adjusting unit adjusts the amount of working fluid in the cylinder based on the second pulse width.

2. The control unit The movable body control device according to claim 1 , wherein the value of the gain is determined based on which of a plurality of conditions the deviation amount satisfies.

3. The control unit The movable body control device according to claim 2 , wherein the value of the gain is determined based on which of three conditions the deviation amount satisfies.

4. The control unit A movable body control device as described in claim 3, wherein if the deviation amount satisfies a first condition of the three conditions, the value of the gain is determined to be a first value, if the deviation amount satisfies a second condition of the three conditions, the value of the gain is determined to be a second value, and if the deviation amount satisfies a third condition of the three conditions, the value of the gain is determined to be a third value.

5. the movable body control device is used for a table of a medical device, the movable body is a subject support portion of the table, The movable body control device according to claim 1 , wherein the first operation signal and the second operation signal are operation signals for changing the height of the table by the target change amount.

6. The movable body control device according to claim 5 , wherein the target change amount is a target change amount when the table is lowered.

7. The movable body control device according to claim 5 , wherein the target change amount is a target change amount when the table is raised.

8. the movable body control device is used in a gantry of a medical device, the movable body is the gantry, The movable body control device according to claim 1 , wherein the first operation signal and the second operation signal are operation signals for changing the tilt angle of the gantry by the target change amount.

9. The movable body control device according to claim 8 , wherein the target change amount is a target change amount when the gantry is tilted toward the front side of the gantry.

10. The movable body control device according to claim 8 , wherein the target change amount is a target change amount when the gantry is tilted toward the rear side of the gantry.

11. The fluid amount adjusting unit is a pump for supplying the working fluid to the cylinder; a valve for discharging the working fluid from the cylinder; The movable object control device according to claim 1 , comprising:

12. The movable body control device according to claim 11 , wherein the pump supplies the cylinder with a quantity of working fluid corresponding to the second pulse width.

13. The movable object control device according to claim 11 , wherein the valve supplies the working fluid from the cylinder in an amount corresponding to the second pulse width.

14. the movable body control device includes a potentiometer that outputs an analog signal representing a voltage corresponding to the movement of the movable body; the control unit includes an ADC that converts an analog signal from the potentiometer into a digital signal; The movable body control device according to claim 1 , wherein the control unit calculates the amount of movement of the movable body based on the digital signal from the ADC.

15. The control unit determining a gain value based on a deviation between an amount of movement of the movable body and the target amount of change every time an operation signal for moving the movable body by a target amount of change is input; Calculating a pulse width to be used when the next operation signal is input based on the deviation amount and the determined gain value. The movable object control device according to claim 1 , wherein the movable object control device executes the above.

16. A non-transitory computer-readable storage medium included in a moving object control device or a non-transitory computer-readable storage medium in communication with the moving object control device, The movable body control device includes: a unit including a cylinder and a piston, at least a portion of the piston being disposed within the cylinder, and configured such that an amount of working fluid within the cylinder is adjusted to move one of the cylinder and the piston relative to the other; a movable body that moves in response to the relative movement of the cylinder and the piston; a control unit that generates, based on a first operation signal input by a user's operation for moving the movable body by a target change amount, a control signal including a first pulse width corresponding to the target change amount so that the movable body moves by the target change amount; a fluid amount adjusting unit that adjusts the amount of working fluid contained in the cylinder based on the first pulse width; Including, the control unit includes one or more processors; The instructions contained in the storage device, when executed by the one or more processors, cause the one or more processors to: determining the amount of movement of the movable body by adjusting the amount of working fluid in the cylinder; determining a gain value based on a deviation between the movement amount of the movable body and the target change amount; calculating a second pulse width based on the deviation amount and the determined gain value; generating a control signal including the second pulse width when a second operation signal for moving the movable body by a target change amount is input after the first operation signal; Execute The fluid amount adjusting unit adjusts the amount of working fluid in the cylinder based on the second pulse width.

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