JP2005131417A - Control method of medical manipulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medical manipulator having high operability for reducing a burden of an operator. <P>SOLUTION: This integral medical manipulator 1 operates in a master-slave system, and has a master part 2 having an operation command part, a slave part 3 having a work part, a connecting part 4 for integrally connecting the master part and the slave part, an attitudinal difference detecting means 6 for detecting an attitudinal difference between an attitude of the master part and an attitude of the slave part, and a control means 7 for controlling the slave part so as to eliminate the attitudinal difference on the basis of the attitudinal difference detected by the attitudinal difference detecting means in a transitional master-slave operation mode up to eliminating the attitudinal difference between the attitude of the master part and the attitude of the slave part by entering a master-slave operation mode from a non-master-slave operation mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a medical manipulator, and more particularly to a method for controlling an integrated medical manipulator that operates in a master-slave manner.

Conventionally, in laparoscopic surgery such as cholecystectomy, a small hole is made in the patient's abdomen,
A trocar is attached to the portion, an endoscope and forceps are inserted through the trocar, and an operator performs an operation while viewing an image of the endoscope on a monitor. Since such an operation method does not require laparotomy, the burden on the patient is small, and the number of days until recovery and discharge from the operation is greatly reduced. Thus, laparoscopic surgery is excellent in that the burden on patients is small, and expansion of the application field is expected. On the other hand, however, the surgeon uses a forceps with poor operability that does not show the affected area directly and is provided only with an open / close gripper, and is not necessarily suitable for surgery, and requires skill of the operator. It was a thing.

Therefore, the degree of freedom of posture is given to the tip of the forceps, the operator operates the operation part (master part) having a plurality of degrees of freedom, and the working part (slave part) of the tip having a plurality of degrees of freedom moves the operation part. Research and introduction of performing laparoscopic surgery with a master-slave system that works together. There is a remote operation type in which a master unit and a slave unit are separated from each other and a complicated system is used (Patent Document 1). In this case, the master unit and the slave unit are located apart from each other, and if the slave unit runs out of control accidentally, it is life-threatening, so there may be a problem in terms of safety as a medical manipulator.

In addition, there is an integrated medical master-slave manipulator in which the master unit and the slave unit have some common axes and are easy to introduce with a simple system. In the field of industrial robots, an integrated manipulator that includes a master unit and a slave unit and operates in a master-slave system is known. However, all of these manipulators enter the master-slave operation mode from the non-master-slave operation mode, and in the transitional master-slave operation mode until the difference in attitude between the attitude of the master unit and the slave unit is resolved, The posture of the part was adapted to match the posture of the slave part. This is because it is easy to adjust the master unit at the operator's hand, and it is not practical to match a heavy slave unit (working unit) to the master unit, particularly in an industrial robot.
Japanese Patent Laid-Open No. 8-323654 FIG.

When operating the medical manipulator by the master-slave system, if the operation starts when the posture relationship between the master unit and the slave unit does not match, the slave does not operate as expected by the operator (operator) and the operability is improved. There is a disadvantage of being bad.

Therefore, a method for matching the posture relationship between the master unit and the slave unit is disclosed, but these are detection means for detecting the respective shapes of the slave unit and the master unit and the detection results by them are compared. In the manipulator provided with the means, the slave unit is stopped, and the surgeon starts the master-slave operation by matching the master unit with the shape of the slave unit. That is, in the transitional master-slave operation mode from the non-master-slave operation mode to the master-slave operation mode, the master unit is controlled to match the attitude of the slave unit.

In this case, when the master / slave operation is started or restarted, there is a problem that the operability is not always good if the surgeon performs shape matching between the slave unit and the master unit one by one. In particular, since a plurality of degrees of freedom have to be matched, there is a problem that it takes time to match the shapes. It is difficult to match the shape of a medical manipulator having a degree of freedom of operation that does not necessarily have to be present on the master side, such as a gripper, only by operating the master unit. These issues are not appropriate from the standpoint of responding to unforeseen circumstances on the spot.

Therefore, the object of the present invention is to solve the problems of the above-described conventional technology, enter the master-slave operation mode from the non-master-slave operation mode, and eliminate the attitude difference between the attitude of the master unit and the attitude of the slave unit. It is to provide a medical manipulator with good operability by controlling the slave unit so as to match the master unit in the transitional master-slave operation mode.

To achieve the above object, the present invention provides a medical manipulator control method comprising a non-master-slave operation mode and a master-slave operation mode, wherein a posture difference between the posture of the master unit and the posture of the slave unit is provided. And a first parameter value for determining whether the predetermined posture of the master unit and the posture of the slave unit match each other and the magnitude of the posture difference are compared. Then, a second used for determining whether or not the predetermined posture of the master unit and the posture of the slave unit are close to each other according to the result of the comparison between the first parameter value and the magnitude of the posture difference. A comparison is made between the parameter value and the magnitude of the attitude difference, or a transition is made to the master-slave operation mode, and a comparison is made between the second parameter value and the magnitude of the attitude difference. If done, depending on the result of the comparison, the time parameter from the input of the signal intended to start the master-slave operation is compared with the current time, or the slave unit decelerates, When a comparison is made between the time parameter and the current time, the slave unit performs a constant speed operation or the slave unit performs an acceleration operation according to a result of the comparison, and the deceleration operation and the constant speed are performed. After the operation or the acceleration operation, the posture difference between the posture of the master unit and the posture of the slave unit is detected again.

According to the present invention, in the transitional master-slave operation mode from the non-master slave operation mode to the master-slave operation mode until the posture difference between the posture of the master unit and the posture of the slave unit is resolved, the posture difference detection means Since the slave unit is controlled so as to be matched with the master unit so that the posture difference is eliminated based on the posture difference detected in step 1, good operability can be obtained. Here, since the integrated medical manipulator that operates in the master-slave system is integrated, even if the slave unit is operated to eliminate the posture difference, the slave unit is within a limited operating space. Because it works, there is no danger of runaway.

Further, according to the present invention, the control means determines in advance over a control time range from when the signal indicating the transition from the non-master-slave operation mode to the master-slave operation mode is received until the attitude difference is resolved. Since the slave unit is controlled based on the relationship between the posture difference amount and the control time, the posture of the slave unit can be quickly and efficiently matched to the posture of the master unit.

As described above, according to the present invention, it is not necessary for the operator to intentionally adjust the shape of the master slave, and the operability is improved. In particular, in the integrated master-slave manipulator in which the shape adjustment is performed in the posture, the safety It is possible to shift to the master / slave operation mode without impairing the operation.

As described above, according to the configuration of the present invention, it is possible to provide a method for controlling a medical manipulator having excellent operability.

Embodiments of a medical manipulator of the present invention will be described below with reference to the drawings.

In the present invention, the non-master-slave operation mode refers to an operation mode in a state where there is no restriction on the posture relationship between the master unit and the slave unit, for example, immediately after the apparatus power is turned on, The mode refers to an operation mode in which the master unit and the slave unit are controlled to have a predetermined attitude relationship. The transitional master-slave operation mode is a part of the initial operation mode in the master-slave operation mode. In the case of entering the master-slave operation mode from the non-master-slave operation mode, it means a transient operation mode until a predetermined attitude relationship is formed between the master unit and the slave unit.

  First, a schematic configuration of the present invention will be described with reference to FIG. 1, FIG. 2, and FIG.

An integrated medical manipulator 1 that operates in a master-slave system includes a master unit (operation command unit) 2 that is operated by an operator, a slave unit (working unit) 3 that operates according to the movement, a master unit 2 and a slave. The connecting part 4 that integrally connects the part 3, the attitude difference detecting means 6 that detects the attitude difference between the attitude of the master part 2 and the attitude of the slave part 3, and the attitude detected by the attitude difference detecting means 6 Based on the difference, control means 7 for controlling the slave unit 3 so that this posture difference is eliminated,
A control program 8 that defines the relationship between the amount of attitude difference created in advance and the control time over the control time range from the detection of the attitude difference by the attitude difference detection means 6 to the elimination of the attitude difference by the control by the control means 7. And.

The posture difference detection means 6 includes an angle detector 21 that detects the posture angle of the master unit 2 and the slave unit 3.
An angle detector 22 that detects the attitude angle of the camera, an angle detector 21, and an attitude difference calculation unit 23 that calculates an attitude difference from the detection angle of the angle detector 22.

The control unit 7 includes a drive unit 9 and a control calculation unit 12. The drive means 9 includes a motor drive circuit 25, a motor 26, and a power transmission unit 27 that transmits the power of the motor 9 to the slave unit 3.
It consists of and.

The slave unit 3 has a plurality of degrees of freedom for performing treatment on the surgical site, and is configured such that the posture of the distal end changes and the gripper can be opened and closed according to an operator's command.

Each degree of freedom of the slave unit 3 operates when the power of the motor 26 is transmitted through a power transmission unit 27 such as a wire or a rod. An encoder is attached to each drive shaft, and the attitude of the slave unit 3 can be detected and the value can be transmitted to the control calculation unit 12.

The master unit 2 is also provided with a plurality of degrees of freedom. Normally, the degrees of freedom of the master unit 2 and the slave unit 3 are the same, but a gripper opening / closing operation command is given by a switch, and the master unit 2 does not always have a gripper like the slave unit 3. . A potentiometer is attached to each degree of freedom of the master unit 2, and the amount of movement as shown in FIG.

The attitude difference obtained by the attitude difference calculation unit 23 is a three-dimensional vector quantity. A control program 8 is created in advance according to the magnitude of the vector quantity. The motion determination unit 14 of the posture difference calculation unit 23 refers to the control program 8 corresponding to the magnitude of the posture difference obtained by the posture difference calculation unit 23 and obtains a control target value for the slave unit 3.

A command value to the slave unit 3 is calculated from the current angle detected by the slave unit 3 and the control target value obtained by the attitude difference calculation unit 23, and is output to the motor drive circuit 25. During the master-slave operation, the attitude angle of the master unit 2 is the control target value of the slave unit 3 as it is.

Next, the procedure for shifting to the master / slave operation will be described. When the medical manipulator 1 is turned on, an initialization procedure is performed. Slave unit 3 is attached by a detector.
The position / orientation is recognized, moved to a predetermined initial position as necessary, and stopped. Master part 2
The position / orientation is detected by the attached detector. Here, usually, the posture relationship between the master unit 2 and the slave unit 3 is often different. For the reason described above, it is necessary to adjust the position and posture between the two.

The surgeon 10 inputs to the controller that the master / slave operation is to be started. Specific input methods include keyboard input, touch panel input, input by the master unit 2 and a switch at hand or foot, or input by a detector that is provided in the trocar 5 and recognizes that the medical manipulator 1 is inserted. There is. As a result, the medical manipulator 1 enters the master-slave operation mode from the non-master-slave operation mode.

When a master-slave operation start command is input, the medical manipulator 1 enters a transitional master-slave operation mode, and calculates an angular difference (posture difference) between the master unit 2 and the slave unit 3 for each axis. To do. This angle difference is compared with a parameter by referring to a predetermined control program 8 and is necessary for establishing a desired posture relationship (the same posture) between the posture relationship between the slave unit 3 and the master unit 2. Determine the operation to shift to master-slave operation.

In the integrated master-slave manipulator, there is no need for alignment because the master unit 2 and the slave unit 3 are integrally connected. Since it is only the posture that needs to be matched, and its movement range is a limited range that can be expected, safety is not impaired even if these degrees of freedom are automatically operated. Even if the master unit 2 and the slave unit 3 are separated, the position is the same if the slave target value is defined as a deviation from the value in the initial state after the start of the master-slave operation.

From the detected angle θmaster of the master unit 2 and the angle θslave of the slave unit 3, an angle difference Δθ between them is obtained from equation (1).

Δθ = θmaster−θslave (1)
The calculation of the angle difference may be performed for each drive axis or each posture axis. Further, the control may be individually performed on a plurality of axes, or a plurality of axes may be combined.

Hereinafter, transition control to the master-slave operation (MS operation) shown in FIGS. 3 and 4 will be described. The current angle difference between the master unit 2 and the slave unit 3 and the master unit 2 and the slave unit 3
Is compared with a parameter value θα for determining whether the values are in agreement with each other.

| Δθ | <θα (2)
When it is determined that the condition of the expression (2) is satisfied, the master / slave operation is started.

If the expression (2) is not satisfied, the second parameter value θβ for determining the angle difference (where θβ>
Compare with θα). This value is used to determine whether both the master unit 2 and the slave unit 3 are approaching. When the following expression (3) is satisfied, the slave unit 3 decelerates to match the posture with the master unit 2. The operation direction is a direction in which the angle difference decreases, and can be obtained from the sign of the angle difference Δθ.

| Δθ | <θβ (3)
When the expression (3) is not satisfied, it is determined that the angle difference between the slave unit 3 and the master unit 2 is large. At this time, the slave unit 3 operates to match the posture with the master unit 2 while generating an acceleration trajectory every moment. The time parameter tγ after the signal intended to start the master / slave operation is compared with the current time t, and the acceleration of the slave unit 3 is determined.

t <tγ (4)
If the formula (4) is satisfied, the slave unit 3 does not satisfy the formula (2) or the formula (3).
Accelerate to the determined speed.

t> tγ (5)
If the formula (5) is satisfied, the slave unit 3 does not satisfy the formula (2) or the formula (3).
It operates at a constant speed to match the attitude of the master. If no acceleration motion is required, the parameter tγ may be set to zero. The time t compared with the parameter tγ is set to zero once the attitude adjustment control has entered the deceleration operation.

By performing the above operation at regular time intervals, the slave unit 3 can automatically match the posture of the master unit 2. This master-slave attitude alignment control method can be similarly applied when resuming a master-slave operation that has been suspended.

Further, in the present invention, since the determination is repeated sequentially from time to time, the posture of the master unit 2 may be moved until the slave unit 3 matches the posture of the master unit 2. That is, if the above-described transition control method is applied, the slave unit 3 generates a target value as shown in FIG. This means that the surgeon 10 does not have to perform the work of adjusting the posture of the slave unit 3 and the master unit 2, but also includes the operation of stopping the master unit 2 from moving until the posture adjustment is completed. It becomes a manipulator with good operability. Further, even if the surgeon 10 moves in the direction of widening the angular difference with the slave unit 3 within the operating range of the master unit 2, the slave unit 3 recognizes that the angular difference between the two has widened, and the comparison result with the parameter Accordingly, it operates so as to match the posture with the master unit 2.

By giving the slave unit 3 a difference in the speed of the operation that matches the posture of the master unit 2 depending on the magnitude of the angle difference, the following capabilities can be provided during the posture adjustment operation. If the posture adjustment is considered to be finished early, the surgeon 10 may move the master unit 2 operated by the operator 10 to the current posture of the slave unit 3. Even if the slave unit 3 starts to decelerate during the posture adjustment, but the postures of the two do not match yet and it is not possible to shift to the master-slave operation, if you want to move further in the current operation direction, The slave unit 3 may be re-accelerated by operating 2 in the direction of escaping from the slave unit 3, that is, in the direction of widening the angle difference.

As described above, it is possible to provide a medical manipulator having an ability to cope with an unexpected situation that may occur in a medical field.

The angle difference between the master unit 2 and the slave unit 3 and the operation time are used for the above-described determination criteria. In addition to or in place of this, the speed ωmaster and acceleration αmaster of the master unit 2 and the angle difference between the two are used. It is possible to generate a target value of the slave unit 3 using the speed Δω and the acceleration Δα, and to request the slave unit 3 for a finer transition operation. By using the speed and acceleration, a virtual spring and damper are provided between the master unit 2 and the slave unit 3 even during the master-slave transition operation, and the operator's intention is reflected more by adjusting the parameters corresponding to them. It becomes easy.

As described above, according to the embodiment of the present invention, the non-master slave operation mode is entered into the master slave operation mode until the attitude difference between the attitude of the master unit 2 and the attitude of the slave unit 3 is resolved. In the transitional master-slave operation mode, based on the attitude difference detected by the attitude difference detection means 6, the slave unit 3 is adjusted to match the master unit 2 so that the attitude difference is eliminated.
As a result, the master unit 2 and the slave unit 3 are automatically adjusted in posture to reduce the burden on the operator 10 and provide a medical manipulator with excellent operability. can do. In addition, it is possible to provide a medical master-slave manipulator that can reflect the operator's intention even during the master-slave posture adjustment and has good operability and safety.

The perspective view which shows the master part of the medical manipulator which concerns on this invention, a slave part, and a connection part. The figure which shows the structure outline of a medical manipulator. The figure which shows the flow of the operation determination in a transitional master slave operation mode. The figure which shows the example of the control program which defined the relationship between the attitude difference amount controlled over the control time range from the time of attitude difference detection until an attitude difference is eliminated, and control time. The figure which shows the example of control when a master part moves during transition operation in transitional master slave operation mode. The figure which shows the example which reaccelerates a slave part by operating in the direction which escapes from a slave part, ie, the direction which widens an angle difference, in a transition master slave operation mode. It is a block diagram explaining control of a medical manipulator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Medical manipulator 2 Master part 3 Slave part 4 Connection part 6 Posture difference detection means 7 Control means 8 Control program 9 Driving means

Claims (1)

A medical manipulator control method comprising a non-master-slave operation mode and a master-slave operation mode,
Detect the posture difference between the posture of the master unit and the posture of the slave unit,
Comparing the first parameter value for determining that the posture of the master unit and the posture of the slave unit, which are determined in advance, coincide with each other as close as possible, and the magnitude of the posture difference;
A second parameter value used for determining whether or not a predetermined posture of the master unit and the posture of the slave unit are close to each other according to a result of the comparison between the first parameter value and the magnitude of the posture difference. Or a comparison with the magnitude of the posture difference, or shift to the master-slave operation mode,
When comparing the second parameter value and the magnitude of the posture difference, a time parameter after the signal intended to start the master-slave operation is input according to the comparison result and the current time. Do a comparison or slow down the slave unit,
When comparing the time parameter and the current time, depending on the result of the comparison, perform a constant speed operation of the slave unit, or perform an acceleration operation of the slave unit,
After the deceleration operation, the constant speed operation, or the acceleration operation, the posture difference between the posture of the master unit and the posture of the slave unit is detected again.
A control method for a medical manipulator characterized by the above.

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