JP2011125580A - Medical device, and method for driving the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power assist function to a medical device for an X-ray imaging apparatus or the like without using a power sensor. <P>SOLUTION: A truck 30 for holding an X-ray generator is held in a Y direction so as to be movable by a moving rail unit 29. For example, if movement in a -Y direction is produced in the truck 30 by the manual operation to the X-ray generator, the movement of the truck 30 is detected by an encoder 52 through the timing belt 42 provided to the moving rail unit 29, the timing pulley 47 provided to the truck 30, a drive gear 48 and an encoder gear 50. A motor 51 is driven on the basis of the encoder value of the encoder 52 and supplies assist drive power for assisting the manual operation through a motor gear 49, the drive gear 48, the timing pulley 47 and the timing belt 42. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a medical device that supplies an auxiliary driving force for assisting manual operation when a driven part is manually operated, and a driving method thereof.

  There is known an X-ray imaging apparatus including an X-ray generator that emits X-rays toward a subject and an X-ray detector that detects X-rays transmitted through the subject. The X-ray generator is held by a holding device that can move in the horizontal and vertical directions so that the X-ray generator can be moved in accordance with the imaging region of the subject. For example, a holding device called a ceiling traveling type suspension device has a rail provided on the ceiling, a carriage that travels on the rail, and a telescopic suspension arm that is suspended from the carriage, at the lower end of the suspension arm. Holds an X-ray generator. The X-ray generator is driven by manual operation using an integrally provided operation handle.

  In order to reduce the load when manually driving the X-ray generator, there is an imaging apparatus provided with a power assist mechanism that supplies an auxiliary driving force to assist the driving of the X-ray generator to the holding device (for example, Patent Documents). 1). In this photographing apparatus, the magnitude and direction of a manual operation force is detected by a force sensor provided at the base of the operation handle, and an auxiliary driving force is supplied based on the detection result.

  As a power assist mechanism that does not use a force sensor, for example, there are inventions described in Patent Documents 2 and 3. In these inventions, when a driven part which is a driving target is manually operated, a motion generated in a shaft support part or the like of the driven part is detected by a sensor, and an auxiliary driving force is supplied based on the detection result. Yes. Further, in order to cause the driven part to move against the static friction of the driven part by manual operation, a static friction compensation torque for compensating the static friction is supplied to the driven part. In the invention described in Patent Document 2, a means for instructing the direction in which the user wants to drive is provided, and the static friction compensation torque is supplied in the instructed direction. In the invention described in Patent Document 3, the static friction compensation torque is supplied in the direction opposite to the previous operation direction.

JP 2000-093416 A JP 2004-344998 A Japanese Patent No. 2762943

  Since the force sensor is heavy, the holding device may bend and the X-ray irradiation field may be shifted. In addition, the force sensor is expensive, and the power assist mechanism needs a large motor for the weight of the force sensor, which increases the cost of the X-ray imaging apparatus. Furthermore, since the force sensor is likely to deteriorate in performance when an external force is applied exceeding the allowable torque, deterioration with time becomes a problem.

  In order to solve the above problem, it is conceivable to apply the power assist mechanism described in Patent Documents 2 and 3 to a medical device such as an X-ray imaging apparatus. However, a medical device generally has a plurality of directions in which a driven part such as an X-ray generator is desired to be driven. If the invention described in Patent Document 2 is used, a plurality of operation means for indicating the driving direction is required. This complicates the structure and operation of the device. Since medical devices need to pay close attention to a patient who is a subject even during the operation thereof, a complicated operation system cannot be applied.

  As a drawback common to Patent Documents 2 and 3, the driven part cannot be moved in an arbitrary direction at an arbitrary timing. That is, when the driven part is driven in a direction different from the direction in which the static friction compensation torque is supplied, it takes time until the power assist works, and smooth manual operation is impaired.

  An object of the present invention is to provide a power assist function in a medical device such as an X-ray imaging apparatus without using a force sensor.

  The medical device of the present invention includes a driven part that is driven in a normal direction and a reverse direction by a manual operation, a driving unit that supplies an auxiliary driving force to assist the manual operation on the driven part, and a manual operation. Drive detection means for detecting the movement generated in the driven part by means of, and the drive direction of the driven part is specified based on the detection result of the drive detection means, and the drive means is controlled to drive in the drive direction of the driven part. Drive control means for supplying force.

  Preferably, the drive control means causes the drive means to supply a static friction compensation torque that compensates for the static friction of the driven part until the drive detection means detects the movement generated in the driven part. Further, the drive control means may cause the drive means to switch the static friction compensation torque between the forward direction and the reverse direction every predetermined period.

  You may provide the operation means which instruct | indicates the supply start and supply stop of a static friction compensation torque. In this case, the drive control means causes the drive means to drive differently from the normal operation when the operation of the operation means is released while the drive means is supplying the auxiliary drive force to the driven part. It is preferable to stop the supply of force.

  The drive means may include a motor and a speed reduction mechanism that decelerates the rotation of the motor and transmits it to the driven part, and a rotation measuring device that detects the rotation of the motor or the speed reduction mechanism may be used as the drive detection means. Further, the drive control means is a displacement value of the driven part obtained based on the detection result of the drive detection means as a command value for driving the motor to generate an auxiliary driving force in the drive means, and a differential value of the displacement amount. Or it is preferable to give the command value which consists of a function of the integral value of speed or acceleration and displacement.

  It is preferable to provide weight canceling means for canceling the weight of the driven part when the driven direction of the driven part is the vertical direction. Further, it is preferable that the drive control means detects an operation state in which the driven part cannot be driven and performs control so as not to perform the auxiliary drive operation during the period. Moreover, it is preferable that the drive detection means is disposed at a position away from a portion to be driven in the vicinity of the subject of the driven portion. Further, an informing means for informing that may be provided during the supply of the static friction compensation torque or the auxiliary driving force, or when the supply of the static friction compensation torque or the auxiliary driving force is started or ended.

  The driven unit may be a part of a holding device that holds the radiation generator or the radiation detector in the radiation imaging apparatus. In addition, the driven unit may be a part of the arm device in an arm type radiographic apparatus having an arm device holding a radiation generator and a radiation detector at both ends. Furthermore, the driven unit may be a part of a holding device that holds the radiation generator in the mobile radiography apparatus. Further, the driven unit may be a part of traveling means for traveling the mobile radiography apparatus.

  According to the medical device driving method of the present invention, when the driven part is driven in the forward direction or the reverse direction by manual operation, the step of detecting the movement generated in the driven part and the driven part based on the detection result And a step of supplying an auxiliary driving force for assisting a manual operation in the driving direction of the driven part.

  It is preferable to include the step of supplying a static friction compensation torque that compensates for the static friction of the driven part until the movement generated in the driven part is detected. Further, it is preferable that the static friction compensation torque is switched between the forward direction and the reverse direction every predetermined period.

  According to the present invention, since the movement generated in the driven part is detected and the auxiliary driving force is supplied, the power assist function is provided in the medical device without using a force sensor that is problematic in terms of cost and durability. Can do. Further, since a heavy force sensor is not used, the weight can be reduced. For this reason, in the case of a radiographic apparatus, the deflection generated in the driven part that holds the radiation generator is reduced, so that the radiation field deviation can be reduced. Further, since no operation means for designating the driving direction is required, the operability is improved.

  Since the static friction compensation torque for compensating the static friction of the driven part is supplied, the driven part can be caused to move with a weak force by manual operation. Furthermore, since the direction of supply of the static friction compensation torque is switched every predetermined period, even if manual operation is performed in a direction different from the direction of supply of the static friction compensation torque, the static friction compensation torque is supplied immediately after a slight delay. Can do.

  Since the operation means for instructing to start and stop the supply of the static friction compensation torque is provided, it is possible to prevent the driven portion from being unintentionally supplied with the auxiliary driving force and to reduce power consumption. In addition, when the operation of the operating means is released, the supply of the auxiliary driving force is stopped by driving different from the normal operation, so that the stopping accuracy and safety are improved.

  The motor of the driving means is driven by giving a command value comprising a displacement amount of the driven portion, a differential value of the displacement amount or a speed or acceleration, and an integral value of the displacement amount, so that an optimum auxiliary driving force can be obtained. it can. Further, since the weight of the driven part is offset, the auxiliary driving force can be supplied without being affected by the weight. Further, since the auxiliary drive operation is not performed when the driven unit is in an operating state in which the driven unit cannot be driven, runaway of the driven unit can be prevented and power consumption can be reduced. Furthermore, since the drive detection means is disposed at a position away from the subject, the field where the drive detection means hits the subject can be prevented, and safety is improved.

1 is a perspective view showing a configuration of a first embodiment of an X-ray imaging apparatus. It is a perspective view which shows the structure of a X-ray generator, a suspension arm, and the drive mechanism for Z axes. It is a top view which shows the upper surface of a trolley | bogie. It is the top view and front view which show the state of the drive mechanism for Z axes when the suspension arm is extending | stretching. It is the top view and front view which show the state of the drive mechanism for Z axes at the time of the suspension arm being contracted. 1 is a block diagram showing an electrical configuration of an X-ray imaging apparatus. It is a timing chart which shows the state where reading of an encoder value and supply of static friction compensation torque are started by operation of a power assist button. It is a flowchart which shows the operation | movement procedure of a power assist function. It is a top view which shows the structure of the C arm type | mold X-ray imaging apparatus of 2nd Embodiment. It is a perspective view which shows the structure of the mobile X-ray imaging apparatus of 3rd Embodiment. It is a side view of a mobile X-ray imaging apparatus. It is a top view of a mobile X-ray imaging apparatus.

[First Embodiment]
An X-ray imaging apparatus 10 shown in FIG. 1 irradiates a subject with X-rays for a short time by an X-ray generator 11, and detects X-rays transmitted through the subject by an X-ray detector 12. I do. In the X-ray imaging apparatus 10, the X-ray generator 11 is held by the overhead traveling suspender 13 in order to move the heavy X-ray generator 11 in the X, Y, and Z directions. The overhead traveling suspender 13 has a power assist function for supplying auxiliary driving force for assisting manual operation when the X-ray generator 11 is driven in the X, Y, and Z directions by manual operation. . Although not shown, the X-ray imaging apparatus 10 includes an imaging control unit that controls the entire apparatus in an integrated manner and processes captured images.

  The X-ray generator 11 includes a columnar X-ray tube 16 arranged so that its axial direction is substantially in the horizontal direction, a box-shaped X-ray restrictor 17 provided at the lower portion of the X-ray tube 16, The operation unit 18 is provided on the front side of the X-ray tube 16 and above the X-ray restrictor 17. The X-ray tube 16 has a cathode filament and an anode target. When a high voltage is applied between the electrodes, electrons emitted from the filament collide with the target to generate X-rays. The X-ray diaphragm 17 has a plurality of lead-plate diaphragm blades that shield X-rays, and the X-ray irradiation range generated by the X-ray tube 16 is limited by displacing each diaphragm blade. .

  The operation unit 18 includes an operation panel 18a having a plurality of operation buttons and a display unit, and an operation handle 18b surrounding the outer periphery of the operation panel 18a. The operation panel 18 a is used for operating the X-ray imaging apparatus 10. The operation handle 18b is gripped by a radiographer when the X-ray generator 11 is driven manually. As shown in FIG. 2, the operation handle 18b is provided with a push button type power assist button 18c at a position where the thumb hits when the photographing engineer holds the operation handle 18b with both hands. When the power assist button 18c is operated, the power assist function of the overhead traveling suspension 13 is activated.

  Behind the X-ray tube 16 is provided an X-ray tube holding portion 21 protruding rearward. The X-ray tube holding part 21 is supported by the rotation support part 22 of the overhead traveling suspension 13 so as to be rotatable in the direction of arrow Q. The X-ray generator 11 can be rotated 90 degrees around the X-ray tube holding unit 21 to irradiate X-rays in the horizontal direction, and therefore can be used for X-ray imaging in a standing position.

  The X-ray detector 12 is disposed below the imaging table 25 on which the subject is placed in a lying state (in a lying position) with the detection surface facing the top plate of the imaging table 25. The X-ray detector 12 is provided so as to be movable in a horizontal direction (Y-axis direction) parallel to the surface of the top plate.

  For the X-ray detector 12, an FPD (Flat Panel Detector) is used. In the FPD, for example, a photoelectric conversion layer such as amorphous silicon (a-Si) or amorphous selenium (a-Se) is formed on an active matrix substrate in which a plurality of TFTs (thin film transistors) are arranged in a matrix for each pixel. It is a detector, and charges stored in each pixel are read out by the TFT and image information is output. As the X-ray detector 12, in addition to the FPD, an IP (imaging plate) using a stimulable phosphor as an image recording medium, an X-ray photosensitive film, or the like may be used.

  The overhead traveling suspension 13 includes a fixed rail unit 28 installed on the ceiling of the X-ray imaging room, a moving rail unit 29 that travels on the fixed rail unit, a cart 30 that travels on the moving rail unit 29, and a cart. An elastically suspended suspension arm 31 suspended downward from 30 and a holding portion 32 that is attached to the lower end of the suspension arm 31 and holds the X-ray generator 11. Thereby, the X-ray generator 11 is movable in the X, Y, and Z directions.

  The fixed rail unit 28 includes a pair of rails 35a and 35b, a pair of holding plates 36a and 36b, and a timing belt 37. The pair of rails 35a and 35b are rod-shaped bodies having a U-shaped cross section, arranged in parallel so that the U-shaped opening sides face each other, and installed on the ceiling so that the longitudinal direction is along the Y direction. Yes. The pair of holding plates 36a and 36b fixes both ends of the rails 35a and 35b, and keeps the interval and parallel of the rails 35a and 35b. The timing belt 37 is a toothed belt in which a rack gear is provided on one surface of a belt-like body formed of rubber or plastic. Both ends of the timing belt 37 are fixed to the holding plates 36a and 36b, and are arranged in parallel between the rails 35a and 35b. The timing belt 37 is used for supplying auxiliary driving force in the Y-axis direction by the power assist function.

  The moving rail unit 29 includes a pair of rails 40 a and 40 b, a pair of holding plates 41 a and 41 b, a timing belt 42, and a carriage unit 43. Since the pair of rails 40a and 40b, the pair of holding plates 41a and 41b, and the timing belt 42 have substantially the same function and shape as the fixed rail unit 28, detailed description is omitted. The carriage unit 43 is provided on the pair of rails 40 a and 40 b, and on the upper part thereof, a roller (not shown) is engaged with the rails 40 a and 40 b, and the moving rail unit 29 is mounted on the fixed rail unit 28. A pair of running portions 43a and 43b are provided that are movable in the + Y direction (forward direction) and the -Y direction (reverse direction).

  FIG. 3 is a plan view illustrating the configuration of the upper surface of the carriage 30. The carriage 30 includes a main body 30a that holds the suspension arm 31 and a pair of running sections 30b and 30c provided on the upper portion of the main body 30a. The running portions 30b and 30c include a rotatable roller 30d that engages with the rails 40a and 40b to move the carriage 30 on the moving rail unit 29 in the + X direction (forward direction) and the −X direction (reverse direction). There are two each.

  The suspension arm 31 includes three rectangular tubes 31a to 31c having different diameters that are slidably fitted, and is extendable in the + Z direction (forward direction) and the −Z direction (reverse direction). The holding | maintenance part 32 is supported by the lower end of the suspension arm 31 so that it can rotate to the arrow U direction. The holding unit 32 is provided with a rotation support unit 22 that supports the X-ray generator 11.

  As shown in FIG. 3, the cart 30 is provided with an X-axis drive mechanism 46 that supplies an auxiliary driving force that assists manual operation when the X-ray generator 11 is driven in the X direction by manual operation. It has been. The X-axis drive mechanism 46 includes a timing belt 42 of the moving rail unit 29, a timing pulley 47 meshed with the timing belt 42, a drive gear 48 provided coaxially with the timing pulley 47, and a motor gear meshed with the drive gear 48. 49, an encoder gear 50, a motor 51 for rotating the motor gear 49, and an encoder 52 for detecting the rotation of the encoder gear 50.

  Driving in the X direction by manual operation of the X-ray generator 11 is detected based on a change in the encoder value read from the encoder 52. The auxiliary driving force is transmitted to the timing belt 42 via the motor 51, the motor gear 49, the driving gear 48, and the timing pulley 47.

  The carriage unit 43 of the moving rail unit 29 is also provided with a Y-axis drive mechanism 54 that supplies auxiliary driving force in the Y direction. As shown in FIG. 1, the Y-axis drive mechanism 54 includes a timing belt 37, a timing pulley 55 that meshes with the timing belt 37, a motor 56, an encoder 57 (see FIG. 6), and the like, Since they have substantially the same configuration, detailed description is omitted.

  The carriage 30 is provided with a Z-axis drive mechanism 59 that supplies auxiliary drive force in the Z-axis direction. As shown in FIG. 2, the Z-axis drive mechanism 59 includes a wire rope 60 that is inserted into the suspension arm 31 and has an end fixed to the holding portion 32, and the wire rope 60 is hung above the suspension arm 31. A pulley 61 and a spring balancer 62 that winds the wire rope 60 are provided. A drive gear 63 provided coaxially with the spring balancer 62, a motor gear 64 and an encoder gear 65 meshing with the drive gear 63, a motor 66 for rotating the motor gear 64, and an encoder 67 for detecting the rotation of the encoder gear 65 are also provided. It is included in the Z-axis drive mechanism 59.

  The Z-axis drive mechanism 59 detects the drive in the Z-axis direction by manual operation of the X-ray generator 11 based on the change in the encoder value of the encoder 67, and rotates the motor 66 via the motor gear 64 and the drive gear 63. This is transmitted to the drum 62b to supply auxiliary driving force in the Z-axis direction.

  The spring balancer 62 is a well-known one used to suspend heavy objects. The spring balancer 62 is rotatably accommodated in the case 62a and the case 62a, and a conical drum 62b around which the wire rope 60 is wound spirally. And a spiral spring (not shown) for urging the drum 62b in the winding direction of the wire rope 60. The spiral spring has an urging force capable of raising the combined weight of the suspension arm 31, the holding portion 32, and the X-ray generator 11, and these weights when the X-ray generator 11 moves in the Z-axis direction. To offset the effects of

  FIGS. 4A and 4B are a plan view and a front view showing a state in which the wire rope 60 is pulled out from the spring balancer 62 and a state in which the wire rope 60 is wound up. As can be seen from these drawings, the wire rope 60 wound around the drum 62b moves from the small diameter side to the large diameter side of the drum 62b as it is fed from the spring balancer 62, and the distance from the center of the drum 62b increases. . Therefore, the spring balancer 62 can cancel out the tension change of the spiral spring and keep the balance between the weight of the suspension arm 31, the holding unit 32 and the X-ray generator 11 and the tension of the spiral spring. A constant lifting force can be exerted regardless of the length of feeding.

  FIG. 6 is a block diagram showing an electrical configuration of the X-ray imaging apparatus 10. The drive control unit 70 controls the drive mechanisms 46, 54, and 59 for the X, Y, and Z axes, specifies the drive direction by manual operation of the X-ray generator 11, and performs auxiliary drive in the drive direction. To supply power. The drive control unit 70 is connected to an imaging control unit 71 that controls the entire X-ray imaging apparatus 10 in an integrated manner. The drive mechanisms 46, 54, and 59 for the X, Y, and Z axes include, for example, motors 51, 56, and 66 that are DC motors, drivers 74, 75, and 76 that drive the motors 51, 56, and 66, and encoders 52, 57, 67.

As shown in FIG. 7A, the drive control unit 70 reads the encoder value Enc (n) from the encoders 52, 57, and 67 for each predetermined sampling period Δt. The sampling period Δt is obtained by, for example, the following formula 1, where t (n) is the time at which the encoder value is read.
Δt = t (n + 1) −t (n) Equation 1

The drive control unit 70 calculates the displacement amount ΔEnc (n) of the encoder value based on the read encoder value Enc (n), and manually operates the X-ray generator 11 based on the change of the displacement amount ΔEnc (n). Is detected and the drive direction is specified. As shown in the following equation 2, the encoder value displacement amount ΔEnc (n) includes the encoder value Enc (n) at time t (n) and the encoder value Enc (n−) at time t (n−1) immediately before the encoder value Enc (n). It is obtained by the difference from 1). When the X-ray generator 11 is not driven, the encoder value and the displacement amount at each time are also constant. However, when the encoders 52, 57, and 67 rotate and the encoder value changes, the displacement amount ΔEnc (n) changes, so that manual operation of the X-ray generator 11 can be detected.
ΔEnc (n) = Enc (n) −Enc (n−1) Equation 2

The drive control unit 70 causes each drive mechanism 46, 54, 59 to generate an auxiliary drive force based on the displacement amount ΔEnc (n). Specifically, a command value W for driving each of the motors 51, 56, and 66 is calculated based on the displacement amount ΔEnc (n). The command value W is composed of a function of a displacement amount ΔEnc (n), a differential value of the displacement amount ΔEnc (n), and an integral value of the displacement amount ΔEnc (n), as shown in the following equation 3, and is applied to the DC motor. On the other hand, it is a value representing supplied power (voltage, current, duty ratio of PWM (Pulse Width Modulation) control, etc.).
W = f (ΔEnc (n), differential value of ΔEnc (n), integral value of ΔEnc (n)) Equation 3

  Since predetermined static friction is generated in the drive mechanisms 46, 54, 59 for the X, Y, and Z axes at rest, even if the X-ray generator 11 is driven manually, the encoders 52, 57 , 67 may cause no detectable motion. Therefore, the drive control unit 70 supplies the static friction compensation torque that compensates for the static friction of each drive mechanism 46, 54, 59 until a manual operation on the X-ray generator 11 is detected. 66 is driven.

  The static friction compensation torque is a torque that does not allow the X-ray generator 11 in the natural state to move without permission, that is, a torque smaller than the static friction force of each drive mechanism 46, 54, 59 (static friction compensation torque < Static friction). For this reason, when a manual operation torque is added to the static friction compensation torque, the total torque exceeds the static friction of each drive mechanism 46, 54, 59 (static friction compensation torque + manual torque> static friction). The generator 11 can be easily driven.

  When the driving direction of manual operation is different from the supply direction of the static friction compensation torque, the effect of the static friction compensation torque cannot be obtained. Therefore, as shown in FIG. 7B, the drive control unit 70 changes the supply direction of the static friction compensation torque between the + direction (forward direction) and the − direction (reverse direction) every switching period T (for example, 50 μs). Has been switched to. Thus, for example, even when a manual operation in the + X direction is performed at time t2 when the static friction compensation torque in the -X direction is supplied to the X-ray generator 11, the stationary in the + X direction is performed after a maximum of 50 μs. Friction compensation torque can be supplied.

  As shown in FIG. 7C, the supply of the static friction compensation torque and the reading of the encoder value are performed only when the power assist button 18c of the operation handle 18b is operated and turned on. This is to prevent runaway of the overhead traveling suspension 13 and reduce power consumption. For the same reason, for example, when the imaging control unit 71 transmits that the X-ray generator 11 is in the X-ray exposure timing, not only the static friction compensation torque is supplied but also the power It is preferable to stop the assist function itself.

  When the operation of the power assist button 18c is released while the auxiliary driving force is being supplied, the drive control unit 70 controls the motors 51, 56, and 66 of the driving mechanisms 46, 54, and 59 to be the command value W described above. It is driven by a different function, and for example, stop driving different from normal auxiliary driving is performed, for example, the X-ray generator 11 is stopped slowly.

  While the power assist function is operating, that is, while the power assist button 18c is being operated, the drive control unit 70 generates a sound indicating that the power assist function is in operation from, for example, the speaker 79 provided in the operation unit 18. generate. As a result, it is possible to inform the photographing engineer that the power assist function is in operation, thereby improving safety.

  The operation of the first embodiment will be described below with reference to the flowchart of FIG. When the power assist button 18c is operated (S1), the drive control unit 70 confirms that the X-ray generator 11 is not in the X-ray exposure timing (S2), and X-ray imaging X, Y, Z Static friction compensation torque is supplied to the shaft drive mechanisms 46, 54, 59 (S3). The static friction compensation torque is switched between the forward direction and the reverse direction every sampling period Δt. In addition, the drive control unit 70 generates a sound indicating that the power assist function is operating from the speaker 79 of the operation unit 18.

  As shown in FIG. 7, when the X-ray generator 11 is driven in the + X direction by manual operation at time t1 when the static friction compensation torque is supplied to the X-axis drive mechanism 46 in the + X direction, the static friction compensation is performed. Since the combined torque of the torque and the manual torque becomes larger than the static friction of the X-axis drive mechanism 46, the X-ray generator 11 immediately moves in the + X direction. When the X-ray generator 11 is driven in the + X direction by manual operation at time t2 when the static friction compensation torque in the -X direction is supplied to the X-axis drive mechanism 46, the X-axis generator 11 is stopped after a maximum of 50 μs. Since the friction compensation torque is switched in the + X direction, the combined torque becomes larger than the static friction of the X-axis drive mechanism 46, and the X-ray generator 11 moves in the + X direction. As a result, the encoder gear 50 rotates via the timing belt 42, the timing pulley 47, and the drive gear 48, and the encoder value Enc (n) of the encoder 52 changes.

  When the power assist button 18c is operated (S1), the drive control unit 70 reads the encoder value Enc (n) from the encoders 52, 57, and 67 for each sampling period Δt (S3), and the encoder value displacement amount ΔEnc. (N) is calculated (S4). As described above, when the encoder value Enc (n) of the encoder 52 changes, the displacement amount ΔEnc (n) also changes, so that the drive control unit 70 determines the X-ray generator 11 based on the change in ΔEnc (n). A manual operation is detected and the drive direction is specified (S5). The drive control unit 70 calculates a command value W of the motor 51 based on the displacement amount ΔEnc (n) (S6), and inputs the command value W to the driver 74. Thereby, the auxiliary driving force in the + X direction is supplied through the motor 51, the motor gear 49, the driving gear 48, the timing pulley 47, and the timing belt 42 (S7).

  For driving the X-ray generator 11 in the Y direction and the Z direction, the static friction compensation torque and the auxiliary driving force are supplied by the Y axis drive mechanism 54 and the Z axis drive mechanism 59 in the same manner as the X direction described above. Is done. Thus, the X-ray generator 11 that needs to be driven in an arbitrary direction at an arbitrary timing can be freely driven with a small force based on the operation intention of the radiographer.

  When the operation of the power assist button 18c is released (S8), the drive control unit 70 calculates the command value W using a function different from the function described above, and causes the motors 51, 56, and 66 to perform normal operation. The X-ray generator 11 is slowly stopped and driven by different driving (S9). Thereby, the stop accuracy and safety are improved. Also, the sound from the speaker 79 is stopped when the operation of the power assist button 18c is released.

  According to the above embodiment, since the power assist function can be realized without using a force sensor, the cost can be reduced, and the deterioration with time unlike the force sensor does not occur, so that the operation reliability is improved. Further, since the X-ray generator 11 can be moved in an arbitrary direction at an arbitrary timing, operability is also improved. Further, by combining a plurality of drive mechanisms so as to be orthogonal to each other by 90 degrees, power assist in three directions of X, Y, and Z can be performed. In addition, since the encoders 52, 57, and 67 of the drive mechanisms 46, 54, and 59 are provided at positions away from the X-ray generator 11 disposed in the vicinity of the subject at the time of X imaging, X-ray generation is performed. The vessel 11 does not increase in size. Thereby, accidents such as the X-ray generator 11 colliding with the subject can be prevented.

  Below, 2nd, 3rd embodiment of this invention is described. In addition, about the same thing as the structure demonstrated in 1st Embodiment, detailed description is abbreviate | omitted using a same sign.

[Second Embodiment]
As shown in FIG. 9, the X-ray imaging apparatus 85 of the second embodiment includes a C-arm type X in which an X-ray generator 11 and an X-ray detector 12 are held at both ends of a C-arm 86 curved in a C shape. X-ray apparatus. The C arm 86 is held by an arm holding mechanism 87 disposed in the vicinity of the imaging table 25 by a plurality of rollers 88 and is movable in the A direction along the bending direction of the C arm 86. The arm holding mechanism 87 is rotatably supported in the B direction by a support shaft 89 extending to the side of the imaging table 25. The C arm 86 is driven in the A direction and the B direction by manual operation using the operation handles 90 to 92 provided on the X-ray generator 11 and the C arm 86. The operation handles 90 to 92 are each provided with a power assist button 93 having the same function as the power assist button 18c of the first embodiment.

  The arm holding mechanism 87 is provided with an A-direction drive mechanism 96 that assists in driving the C-arm 86 in the A direction. The A-direction drive mechanism 96 includes an arc-shaped rack gear 86a provided on the outer peripheral surface of the C arm 86, a motor 97 and an encoder 98 meshed with the rack gear 86a by a motor gear and an encoder gear. The support shaft 89 is provided with a B-direction drive mechanism 99 that assists the rotation of the C-arm 86 in the B direction. The B-direction drive mechanism 99 includes a drive gear 100 provided coaxially with the support shaft 89, a motor gear 101 that meshes with the drive gear 100, and a motor with an encoder to which the motor gear 101 is attached and is configured by a motor 102a and an encoder 102b. 102.

  Although not shown, the X-ray imaging apparatus 85 includes a drive control unit having the same function as the drive control unit 70 of the first embodiment. This drive control unit controls the A-direction drive mechanism 96 and the B-direction drive mechanism 99 in accordance with the operation of the power assist button 93.

  As in the first embodiment, when the power assist button 93 is turned on, the X-ray imaging apparatus 85 is supplied with static friction compensation torque in the forward and reverse directions in the A and B directions by the motors 97 and 102a. Further, when the movement of the C arm 86 is detected by the encoders 98 and 102b, auxiliary driving force is supplied in the driving direction. Thus, even in the C-arm type X-ray imaging apparatus, a power assist mechanism can be provided without using a force sensor. Note that this embodiment is also applicable to a U-arm type X-ray imaging apparatus.

[Third Embodiment]
As shown in FIG. 10, the X-ray imaging apparatus 105 according to the third embodiment is a mobile X-ray imaging apparatus that can be moved by a round wheel 106. The X-ray generation unit 11 is held by a horizontal arm 108 that protrudes horizontally from a support column 107 that stands on the round wheel 106. The X-ray detector 12 is connected to the roundabout wheel 106 via a cable 12a. The round-trip wheel 106 includes an imaging control unit that performs X-ray imaging by comprehensively controlling the X-ray generator 11 and the X-ray detector 12 and performs image processing. In addition, a monitor 109 used for photographing operation and confirmation of a photographed image is provided on the upper portion of the round wheel 106.

  The support column 107 is rotatable in the direction of arrow J around its vertical axis. Further, the horizontal arm 108 is movable in the K direction that is the vertical direction along the support column 107 and the M direction that is the horizontal direction orthogonal to the longitudinal direction of the support column 107. The round-trip wheel 106 travels in the F direction, which is the forward direction with the side where the support column 107 is provided as the head, and the R direction, which is the reverse direction. Further, the round-trip wheel 106 has a left-right direction FR, FL, RR. It can turn in the RL direction.

  The support column 107 and the horizontal arm 108 are driven in the J, M, and K directions by manual operation using the operation handle 112 provided in the X-ray generator 11. The round wheel 106 is driven in the F, FR, FL, R, RR, and RL directions by manual operation using the operation handle 113 provided at the rear. The operation handles 112 and 113 are provided with power assist buttons 112a and 113a having the same function as the power assist button 18c of the first embodiment, respectively.

  As shown in FIG. 11, a J-direction drive mechanism 116 that supplies static friction compensation torque in the forward / reverse direction and auxiliary drive force in the J direction of the support column 107 is provided in the round wheel 106. The J-direction drive mechanism 116 is attached to a rotary shaft 117 that rotatably supports the support column 107, a drive gear 118 that is provided coaxially with the rotary shaft 117, a motor gear 119 that meshes with the drive gear 118, and the motor gear 119. And a motor 120 with an encoder.

  A K-direction drive mechanism 123 that supplies static friction compensation torque in the forward and reverse directions and an auxiliary drive force in the K direction of the horizontal arm 108 is provided in the support column 107. The K-direction drive mechanism 123 includes a rack gear 124 arranged in the vertical direction in the support column 107, a motor 125 that is attached to the horizontal arm 108 and meshed with the rack gear 124 by the motor gear, and an encoder meshed with the motor gear by the encoder gear. 126.

  The horizontal arm 108 is provided with an M-direction drive mechanism 129 that supplies a static friction compensation torque in the forward and reverse directions and an auxiliary drive force in the M direction of the horizontal arm 108. The M-direction drive mechanism 129 is attached to the horizontal arm 108 along the horizontal direction in the horizontal arm 108, the motor 131 that is attached to the horizontal arm 108, meshed with the rack gear 130 by the motor gear, and meshed with the motor gear by the encoder gear. And an encoder 132.

  As shown in FIG. 12, a left rear wheel drive mechanism 135 </ b> L and a right rear wheel drive mechanism 135 </ b> R for supplying static friction compensation torque and auxiliary drive force in the F and R directions are provided in the round wheel 106. Yes. The left rear wheel drive mechanism 135L includes a drive gear 137L provided coaxially with the left rear wheel 136L, a motor gear 138L meshing with the drive gear 137L, and a motor with encoder 139L attached to the motor gear 138L. Since the right rear wheel drive mechanism 135R has the same configuration as the left rear wheel drive mechanism 135L, detailed description thereof is omitted.

  Although not shown, the X-ray imaging apparatus 105 includes a drive control unit having the same function as the drive control unit 70 of the first embodiment. The drive control unit controls the J-direction drive mechanism 116, the K-direction drive mechanism 123, and the M-direction drive mechanism 129 in accordance with the operation of the power assist button 112a. The drive control unit controls the left rear wheel drive mechanism 135L and the right rear wheel drive mechanism 135R in accordance with the operation of the power assist button 112a.

  When the power assist button 112a of the operation handle 112 is turned on, the X-ray imaging apparatus 105 is supplied with static friction compensation torque in the forward and reverse directions in the J, M, and K directions by the motor 120 with encoder and the motors 125 and 131. The When the movement of the column 107 or the horizontal arm 108 is detected by the motor 120 with encoder and the encoders 126 and 132, the auxiliary driving force is supplied in the driving direction.

  When the power assist button 113a of the operation handle 113 is turned on, static friction compensation torque in the forward and reverse directions is supplied in the F and R directions by the motors 139L and 139R with encoder. When the movement of the round wheel 106 is detected by the encoder-equipped motors 139L and 139R, auxiliary driving force is supplied in the driving direction.

  When the round wheel 106 is manually operated in the F direction or the R direction, an auxiliary driving force for rotating the left rear wheel 136L and the right rear wheel 136R in the same direction is supplied, and the round wheel 106 is moved in the F direction or the R direction. Go straight on. Further, when the round wheel 106 is manually operated to any one of FR, FL, RR, and RL, auxiliary driving force for rotating the left rear wheel 136L and the right rear wheel 136R in the opposite directions is supplied, and the round wheel 106 is It turns in any direction of FR, FL, RR, RL. Thus, even in the mobile X-ray imaging apparatus, a power assist mechanism can be provided without using a force sensor.

  In each of the above embodiments, a push button type power assist button is used, but, for example, a micro switch, a piezoelectric switch, a capacitance switch, a strain gauge, or the like may be used. Moreover, although the encoder was used for the drive detection of each part, you may use other rotation measuring devices, such as a potentiometer.

  Although a DC motor is used as the motor, a stepping motor, a servo motor, an AC motor, or the like may be used. In this case, the stepping motor or the servo motor is supplied with the number of pulses, the pulse frequency, etc. as the command value W. In the case of an AC motor, voltage, frequency, etc. are supplied as the command value W. Further, the motor and the encoder may be integrated or separated.

The command value W is calculated as a function of the displacement amount ΔEnc (n), the differential value of the displacement amount ΔEnc (n), and the integral value of the displacement amount ΔEnc (n), but instead of the differential value of ΔEnc (n). Alternatively, ΔEnc (n) −ΔEnc (n−1) corresponding to a digital system may be used. Further, Enc (n) or acceleration may be used instead of the integral value of ΔEnc (n). The command value W may be a general PID control function expressed by the following equation 4.
W = PΔEnc + I∫ΔEnc · dt + d (ΔEnc) Equation 4

  Further, the servo control circuit disclosed in Japanese Patent Application Laid-Open No. 2004-344998 or Japanese Patent Application Laid-Open No. 08-155868 may be used for calculating the command value W (see FIGS. 16 and 5 of each document). According to this, the command value W is obtained by offsetting the gravity compensation amount so as to cancel the gravity applied as a load to each part of the overhead traveling suspension device 13 and adding the deviation of the encoder value and the integral value of the speed. Can do.

  Further, although a spring balancer is used to cancel the weight of the X-ray generator or the like, a counterweight may be used. Moreover, although driving of the X-ray generator has been described as an example, it may be used for driving the X-ray detector. Further, although the sound is generated from the speaker during the operation of the power assist function, the sound may be generated only at the start or end of the operation. Further, it may be notified visually that the power assist function is in operation by displaying light, characters, symbols, or the like. Further, the second embodiment and the third embodiment can be combined and applied to a C-arm or U-arm type mobile X-ray imaging apparatus. Furthermore, although the X-ray imaging apparatus has been described as an example, the present invention can also be applied to other medical devices.

DESCRIPTION OF SYMBOLS 10 X-ray operation apparatus 11 X-ray generator 12 X-ray detector 13 Ceiling traveling type suspension device 18b Operation handle 18c Power assist button 28 Fixed rail unit 29 Moving rail unit 30 Cart 31 Suspension arm 46 X axis drive mechanism 54 Y axis Drive mechanism 59 Z-axis drive mechanism 51, 56, 66 Motor 52, 57, 67 Encoder 62 Spring balancer 70 Drive controller 85 C-arm X-ray imaging apparatus 105 Mobile X-ray imaging apparatus

Claims (18)

A driven part that is driven in the forward and reverse directions by manual operation;
Driving means for supplying an auxiliary driving force for assisting a manual operation to the driven part to the driven part;
Drive detection means for detecting movement generated in the driven part by manual operation;
Drive control means for specifying the drive direction of the driven part based on the detection result of the drive detection means, and for controlling the drive means to supply the auxiliary driving force in the drive direction of the driven part. Medical device characterized by that.   The drive control means causes the drive means to supply a static friction compensation torque that compensates for the static friction of the driven part until the drive detection means detects a movement generated in the driven part. The medical device according to claim 1.   The medical device according to claim 2, wherein the drive control unit causes the drive unit to switch the static friction compensation torque between a normal direction and a reverse direction at predetermined intervals.   The medical device according to any one of claims 1 to 3, further comprising operation means for instructing start and stop of supply of the static friction compensation torque.   The drive control means causes the drive means to drive differently from the normal operation when the operation of the operation means is released while the drive means is supplying the auxiliary driving force to the driven part. The medical device according to claim 4, wherein the supply of the auxiliary driving force is stopped.   The drive means includes a motor and a speed reduction mechanism that reduces the rotation of the motor and transmits it to the driven part, and the drive detection means detects a rotation of the motor or the speed reduction mechanism. The medical device according to any one of claims 1 to 5, wherein:   The drive control means, as a command value for driving the motor to cause the drive means to generate the auxiliary driving force, a displacement amount and displacement of the driven part obtained based on a detection result of the drive detection means 7. A medical device according to claim 6, wherein a command value comprising a differential value of quantity or a function of speed or acceleration and an integral value of displacement is given.   8. The medical device according to claim 1, further comprising weight canceling means for canceling the weight of the driven part when the driving direction of the driven part is a vertical direction.   The medical device according to claim 1, wherein the drive control unit detects an operation state in which the driven unit cannot be driven, and does not perform an auxiliary drive operation during the period.   The medical device according to any one of claims 1 to 9, wherein the drive detection means is disposed at a position away from a portion driven in the vicinity of the subject of the driven portion.   An informing means for informing the fact is provided during supply of the static friction compensation torque or the auxiliary driving force, or when supply of the static friction compensation torque or the auxiliary driving force is started or ended. Item 3. A medical device according to Item 2.   The medical device according to claim 1, wherein the driven portion is a part of a holding device that holds a radiation generator or a radiation detector in the radiation imaging apparatus.   12. The arm-type radiography apparatus having an arm apparatus having a radiation generator and a radiation detector held at both ends, wherein the driven part is a part of the arm apparatus. The medical device described.   The medical device according to claim 1, wherein the driven unit is a part of a holding device that holds a radiation generator in the mobile radiography apparatus.   The medical device according to claim 14, wherein the driven part is a part of a traveling unit that causes the mobile radiographic apparatus to travel. Detecting a movement generated in the driven part when the driven part is driven in a forward direction or a reverse direction by a manual operation;
A drive direction of the medical device, comprising: specifying a driving direction of the driven portion based on the detection result, and supplying an auxiliary driving force for assisting a manual operation in the driving direction of the driven portion. Method.   The method for driving a medical device according to claim 16, further comprising a step of supplying a static friction compensation torque that compensates for the static friction of the driven part until the movement generated in the driven part is detected.   18. The method of driving a medical device according to claim 17, wherein the static friction compensation torque is switched between a forward direction and a reverse direction every predetermined period.

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