Control apparatus for endoscope apparatus and endoscope apparatus

An endoscope apparatus includes an elongated insertion portion, a self-propelling mechanism configured to be rotatably driven to advance and retract the insertion portion, and a motor configured to supply a drive force to the self-propelling mechanism. A control apparatus for the endoscope apparatus includes a current controller configured to supply a motor current to the motor to control driving of the motor, a motor current detector configured to detect a value of the motor current, a motor current change amount detector configured to detect an amount of change in the value of the motor current, and a limit controller configured to stop a supply of the motor current by the current controller according to the amount of change.

FIELD

Exemplary embodiments relate to a control apparatus for an endoscope apparatus and an endoscope apparatus.

BACKGROUND

Known as endoscope apparatuses for insertion into the lumen are self-propelling endoscope apparatuses. Self-propelling endoscope apparatuses advance and retract an insertion portion by propulsive force generated by, for example, rotating a rotating body provided about the insertion portion by a motor. The inserting or retracting operations of the insertion portion of such endoscope apparatuses performed by a user are assisted.

Endoscope apparatuses generally have a torque limit function for stopping rotation when the motor torque (motor current) for the self-propelling becomes equal to or greater than a predetermined torque limit value. For example, Jpn. Pat. Appin. KOKAI Publication No. 2014-004268 suggests an endoscope insertion assisting tool that sets, as a torque limit value, a value obtained by adding a fixed value to a minimum torque value within a predetermined time that is stored in a torque history unit. According to Jpn. Pat. Appin. KOKAI Publication No. 2014-004268, the torque limit value is set in consideration of the internal resistance of the self-propelling mechanism.

SUMMARY

According to an embodiment, there is provided a control apparatus for an endoscope apparatus including an elongated insertion portion, a self-propelling mechanism configured to be rotatably driven to advance and retract the insertion portion, and a motor configured to supply a drive force to the self-propelling mechanism, the control apparatus comprising: a current controller configured to supply a motor current to the motor to control driving of the motor; a motor current detector configured to detect a value of the motor current; a motor current change amount detector configured to detect an amount of change in the value of the motor current; and a limit controller configured to stop a supply of the motor current by the current controller according to the amount of change.

According to an embodiment, there is provided an endoscope apparatus comprising: an elongated insertion portion; a self-propelling mechanism configured to be rotationally driven to advance and retract the insertion portion; a motor configured to supply a drive force to the self-propelling mechanism; a current controller configured to supply a motor current to the motor to control driving of the motor; a motor current detector configured to detect a value of the motor current; a motor current change amount detector configured to detect an amount of change in the value of the motor current; and a limit controller configured to stop a supply of the motor current by the current controller according to the amount of change.

Advantages of the embodiments will be set forth in the description which follows, and in part will be obvious from the description, or may be learned. The advantages may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.FIG. 1is a schematic view showing a configuration of the endoscope apparatus according to an embodiment of the present invention. As shown in the figure, an endoscope apparatus1includes an endoscope100and a control apparatus200. It should be noted that the endoscope apparatus1in fact includes a light source apparatus for controlling the illumination inside the living body from the endoscope100, and a monitor for displaying images obtained by the endoscope100. However, the light source apparatus and the monitor are not shown inFIG. 1.

The endoscope100is a rotary self-propelling endoscope with an insertion portion102. The insertion portion102is elongated and configured to be inserted into a living body. The endoscope100further includes a control unit108for performing various operations of the endoscope100. The control unit108is held by a user. Hereinafter, the side where the distal end of the insertion portion102is will be referred to as the distal end side, and the side where the control unit108of the insertion portion102is provided will be referred to as the proximal end side. The direction from the distal end side to the proximal end side of the insertion portion102is defined as the longitudinal direction. The control unit108of the endoscope100and the control apparatus200are connected via a cable110.

The distal end portion of the insertion portion102is configured not to be bent. An image sensor is provided at the distal end portion. The image sensor generates an image signal based on, for example, a subject image on the distal end side of the insertion portion102. The image signal generated by the image sensor is transmitted to the control apparatus200via an image signal line running through the insertion portion102and the cable110.

The proximal end side of the insertion portion102includes a portion actively bending according to operations of an operating unit181provided in the control unit108, and a portion passively bending according to external force. Attached to the bending portion of the insertion portion102is a rotating unit104for transmitting the drive force of a motor182that is built into the control unit108. Attached to the distal end side of the rotating unit104is a power spiral tube106that is a rotating body. The power spiral tube106is tubular-shaped and made from a soft material such as a rubber or resin, and mounted to be rotatable about the longitudinal axis of the bending portion. On the outer peripheral surface of the power spiral tube106, a spiral fin161along the longitudinal axis of the power spiral tube106is provided. It should be noted that the power spiral tube106may be configured to be detachable from the rotating unit104.

The motor182is connected to the control apparatus200via an actuator current signal line running through the control unit108and the cable110. The motor182operates by operations using an operator204. The rotational force of the motor182is transmitted to the rotating unit104. As a result, the fin161provided on the power spiral tube106rotates about the longitudinal axis.

The fin161rotating while being in contact with a wall portion such as the inner wall of the lumen generates a frictional force. The fin161contacting, for example, folds in the small intestine and the large intestine present on the inner wall of the small intestine or the large intestine causes frictional force to act onto the insertion portion102. This frictional force causes the insertion portion102to self-propel. As the insertion portion102self-propels, the user's insertion operation and retraction operation of the insertion portion102are being assisted. It should be noted that when the motor182rotates forward, the insertion portion102self-propels in the direction of insertion, and that when the motor182rotates backward, the insertion portion102self-propels in the direction of retraction. The motor182comprises a pulse generator. The pulse generator generates a pulse signal (rotation speed signal) corresponding to the rotation speed of the motor182. The pulse generator inputs the rotation speed signal to the control apparatus200via a rotation speed signal line running through the cable110. The rotational speed signal controls the rotational speed of the motor182.

The operator204is, for example, a foot switch. The foot switch includes a forward pedal and a backward pedal. When the forward pedal is depressed by the user, an instruction signal for rotating the motor182forward is output. When the backward pedal is depressed by the user, an instruction signal for rotating the motor182backward is output. The forward pedal and the backward pedal are each configured to generate a signal with magnitudes corresponding to the amount of depression. Although in the present scenario, it is assumed that the operator204is a foot switch, the operator204may be, for example, a switch etc. provided in the control unit108.

The control apparatus200controls each element of the endoscope apparatus1. The control apparatus200comprises at least a drive controller202. The drive controller202is composed of, for example, a CPU and an ASIC, and includes the function of a motor current detector2021, the function of a motor current change amount detector2022, the function of a limit controller2023, and the function of a current controller2024. Each of these functions of the drive controller202may be realized by a single hardware or software, or by a plurality of hardware or software. Some of the functions may also be provided separately from the drive controller202.

The motor current detector2021detects motor current values as drive currents of the motor182output from the current controller2024, and inputs the detected motor current values to the motor current change amount detector2022.

The motor current change amount detector2022detects an amount of variation in the motor current values over a predetermined period (for example, 200 ms). This amount of variation in the motor current values is, for example, the increase rate of the motor current during a set period of time. The increase rate of the motor current is expressed as the motor current delta obtained over the set period of time divided by time.

The limit controller2023controls, based on the motor current value change amount detected by the motor current change amount detector2022, the torque limit function for the motor182. This torque limit function is a process of stopping the motor182by stopping the supply of motor current from the current controller2024to the motor182, and thereby suppressing the rise in torque of the motor182. In the present embodiment, the limit controller2023determines whether or not to cause the torque limit function for the motor182to operate by determining whether or not the motor current value is equal to or greater than a torque limit value that is a predetermined current threshold value. The limit controller2023further changes the torque limit value according to the increase rate of the motor current. For example, the limit controller2023includes a memory for storing a table associating increase rates and torque limit values as shown inFIG. 2, and, by using the torque limit value corresponding to the increase rate of the motor current detected by the motor current change amount detector2022, the limit controller2023determines whether or not the torque limit function should operate. It should be noted that the torque limit value decreases as the increase rate increases, as shown inFIG. 2. If the increase rate of the motor current is large, for example, when the internal load suddenly increases, the torque limit function should really operate. If the torque limit function should really operate, the torque limit value is set small so that the torque limit function can operate easily. Conversely, if the increase rate of the motor current is small, the torque limit function does not instantly need to operate. If the torque limit function does not really need to operate, the torque limit value is set great to make operating the torque limit function difficult. It should be noted that the numerical values and ranges shown inFIG. 2are merely examples and that they can be changed appropriately.

The current controller2024controls the motor current value to be output to the motor182by changing the motor voltage by fetching, at predetermined sampling intervals, a rotation speed signal output by the pulse generator of the controller108, and using the fetched rotation speed signal as a feedback signal to convert the rotation speed of the motor182into the rotational speed instructed from the operator204. When the instruction to cause the torque limit function to operate is received from the limit controller2023, the current controller2024stops the motor current input to the motor182.

Hereinafter, the operations of the endoscope apparatus1according to the embodiment of the present invention will be described.FIG. 3is a flowchart showing an example of the operations of the endoscope apparatus1according to the embodiment. The operations inFIG. 3are controlled by the drive controller202of the control apparatus200. These operations are started, for example, when the power source of the endoscope apparatus1is turned on. It should be noted that a process in parallel with the operations inFIG. 3is performed by which endoscopic images are displayed onto a monitor based on image signals obtained by the image sensor.

In step S101, the drive controller202determines whether or not the operator204has operated. If, for example, the operator204is the foot switch, it is determined whether or not the forward pedal or the backward pedal has been depressed. As long as it is determined in step S101that the operator204has not operated, the determination in step S101is repeated. If it is determined in step S101that the operator204has operated, the process continues to step S102.

In step S102, the drive controller202controls the drive of the motor182using the current controller2024. That is, the current controller2024of the drive controller202changes the motor voltage so that the rotation speed of the motor182becomes the rotation speed corresponding to the depression amount of the foot switch being the operator204. Subsequently, the process continues to step S103.

In step S103, the motor current detector2021of the drive controller202detects the motor current. The motor current is detected at predetermined time intervals.

In step S104, the motor current change amount detector2022of the drive controller202detects the rate of increase in the motor current detected by the motor current detector2021at the predetermined time intervals.

In step S105, the limit controller2023of the drive controller202determines whether or not the motor current value detected by the motor current detector2021is equal to or greater than the torque limit value corresponding to the increase rate detected by the motor current change amount detector2022. As described above, the table associating the increase rates and torque limit values is stored in advance in the memory of the limit controller2023. If it is determined in step S105that the motor current value is not equal to or greater than the torque limit value, the process returns to step S101. If it is determined in step S105that the motor current value is equal to or greater than the torque limit value, the process proceeds to step S106.

In step S106, the limit controller2023of the drive controller202instructs the current controller2024to cause the torque limit function to operate. In response to the instruction, the current controller2024stops the motor182by stopping the supply of motor current to the motor182. It should be noted that the user may be notified according to the operations of the torque limit function that the torque limit function has operated.

In step S107, the drive controller202determines whether or not the operator204has re-operated. If, for example, the operator204is the foot switch, the operator204has re-operated if the foot switch is released and then depressed again. As long as it is determined in step S107that the operator204has not re-operated, the determination in step S107is repeated. If it is determined in step S107that the operator204has re-operated, the process returns to step S101.

As described above, according to the present embodiment, the operations of the torque limit function are controlled according to the torque limit value corresponding to the change amount of the motor current. By adopting, for example, the increase rate of the motor current as the change amount of the motor current, it is possible, for example, to reduce the torque limit value when the torque limit function should really operate, e.g. when a sudden rise occurs in internal load, and to increase the torque limit value otherwise, when the torque limit function does not really need to operate, e.g. when the torque rises due to the bending of the spiral tube portion. In this manner, it is possible to suppress the operations of the torque limit function except if needed. This consequently shortens the inspection time and the like.

Hereinafter, a modification of the present embodiment will be described. In the above embodiment, the increase rate of the motor current has been used as the change amount of the motor current. However, the change amount of the motor current does not have to be the increase rate of the motor current. The below modification is an example using the motor current integrated value during a predetermined period as the change amount of the motor current. It should be noted that the basic configuration of the endoscope apparatus of the present modification is the same as the configuration described with reference toFIG. 1. In this modification, the motor current change amount detector2022detects the motor current integrated value over a predetermined period of time as the change amount of the motor current value.

Hereinafter, the operations of the endoscope apparatus1according to the modification will be described.FIG. 4is a flowchart showing an example of the operations of the endoscope apparatus1according to the modification. It should be noted that description of those processes similar to those inFIG. 3will be omitted as appropriate.

In step S201, the drive controller202determines whether or not the operator204has operated. As long as it is determined in step S201that the operator204has not operated, the determination in step S201is repeated. When it is determined in step S201that the operator204has operated, the process proceeds to step S202.

In step S202, the drive controller202controls the drive of the motor182using the current controller2024.

In step S203, the motor current detector2021of the drive controller202detects the motor current. The motor current detector2021detects the motor current at, for example, predetermined time intervals (25 ms).

In step S204, the motor current change amount detector2022of the drive controller202detects the motor current integrated value in the motor current detector2021. The motor current integrated value is, for example, the integrated value since the point in time at which the predetermined limit reference value is reached or exceeded. For example, in the example ofFIG. 5, the limit reference value is 150 mA. In this case, as shown by the dashed line boxes inFIG. 5, the detection of the integrated value is started when the motor current value reaches 150 mA or more, and when the motor current value falls below the limit reference value, the detection of the integrated value is terminated. At this point, the integrated value is reset.

In step S205, the limit controller2023of the drive controller202determines whether or not the value of the integrated value is equal to or greater than the predetermined threshold value (for example, 800 mA). It should be noted that this threshold value is stored in advance in the memory of the limit controller2023. If it is determined in step S205that the integrated value is not equal to or greater than the threshold value, the process returns to step S201. If it is determined in step S205that the integrated value is equal to or greater than the threshold value, the process proceeds to step S206. Since the operations of the torque limit function are determined by the integrated value, the time until the torque limit function operates decreases if a motor current flows which is much greater than the limit reference value (see first integrated part inFIG. 5), and conversely, the time until the torque limit function operates increases if a motor current flows which is close to the limit reference value (see second integrated part inFIG. 5).

In step S206, the limit controller2023of the drive controller202instructs the current controller2024to cause the torque limit function to operate. In response to the instruction, the current controller2024stops the motor182by stopping the supply of motor current to the motor182. It should be noted that the user may be notified according to the operations of the torque limit function that the torque limit function has operated.

In step S207, the drive controller202determines whether or not the operator204has re-operated. As long as it is determined in step S207that the operator204has not re-operated, the determination in step S207is repeated. If it is determined in step S207that the operator204has re-operated, the process returns to step S201.

As described above, according to the present modification, the operation of the torque limit function is controlled in accordance with the torque limit value corresponding to the change amount of the motor current as in the embodiment. By adopting, for example, the motor current integrated value as the change amount of the motor current, it is possible to set the time at which the torque limit function should really operate, e.g. when a sudden rise in the internal load occurs, similar to the case in which the increase rate is adopted.

According to the present modification, it is determined, based on the integrated value, whether or not the torque limit function should operate. Although the motor current value suddenly rises even when, for example, starting the motor, the instantaneous change in motor current can be ignored by determining, based on the integrated value, whether or not the torque limit function should operate. In this manner, the likelihood of making erroneous determinations on the operations of the torque limit function can be reduced.

It should be noted that although in the present modification the integrated value is directly compared with the threshold value, the integrated value and the torque limit value may be associated as in the embodiment, and whether or not the torque limit function should operate may be determined by comparing the torque limit value corresponding to the integrated value with the motor current value. When associating the integrated value with the torque limit value, the torque limit value is set small if the motor current integrated value is large, and the torque limit value is set large if the motor current integrated value is small. Further, although in the modification, the motor current integrated value exceeding the reference value is compared with the threshold value, the integrated value that includes the motor current not exceeding the reference value may be compared with the threshold value.

Although the present invention has been described based on the above embodiment, the present invention is not limited to the above embodiment, meaning that various modifications and applications within the scope of the gist of the present invention are obviously possible. For example, in the above embodiment, the rotating body for advancing and retracting the insertion portion102of the endoscope100is the power spiral tube106, but in contrast to this, the art of the present embodiment is applicable to various insertion devices that advance and retract the insertion portion102by the rotating body.

Each of the processes of the above embodiment can be stored as a program executable by the drive controller202that is a computer. Each of the processes can also be stored in a storage medium of an external storage device such as a magnetic disk, an optical disk, a semiconductor memory, and which can then be distributed. The drive controller202can read the program stored in the storage medium of the external storage device, so that the operations can be controlled using the read program to execute the above processes.