JP2004338057A - Safety control system for medical robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically stop a medical robot in an instant when the medical robot runs away or malfunctions. <P>SOLUTION: A manipulator driving device 12 is provided with a first hydraulic cylinder 35 for operating a manipulator 11, and an emergency stop means 40 for stopping the drive of the first hydraulic cylinder 35 in an emergency. The emergency stop means 40 is provided with a state detecting part 47 for detecting the surface pressure of the manipulator 11; solenoid selector valves 49, 50 having a permitting position of permitting the water supply and drainage of the first hydraulic cylinder 35 and a shutoff position of shutting off the water supply and drainage; and a changeover control part 54 for controlling the changeover operation of the solenoid selector valves 49, 50. The changeover control part 54 changes the solenoid selector valves 49, 50 from the permitting position to the shutoff position in the case of determining the operation of the manipulator 11 to be abnormal from the detection value of the state detecting part 47. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a safety control system for a medical robot, and more particularly, to a safety control system for a medical robot capable of automatically and instantaneously stopping the medical robot when the medical robot runs away or malfunctions.
[0002]
[Prior art]
In recent years, medical robots for performing minimally invasive surgery that do not require a large incision are becoming widespread. For example, a medical robot disclosed in Patent Literature 1 is known. This medical robot is provided with a manipulator provided with an endoscope and a treatment tool on the distal end side, and after inserting the manipulator into the body, it is possible to perform a treatment on an affected part by remote control of an operator. The manipulator is operated by a servomotor controlled by a predetermined control device. In addition, when the manipulator runs away or malfunctions, this medical robot artificially activates a switch arranged at the foot of the operator, thereby causing the control device to shut down the system and forcing the operation of the manipulator. Can be stopped temporarily.
[0003]
[Patent Document 1]
JP-A-9-66056
[Problems to be solved by the invention]
However, such a medical robot is insufficient to instantly stop runaway or malfunction. That is, the emergency operation of the manipulator requires an operator to operate a switch. As a prerequisite, the operator must recognize the runaway or malfunction of the manipulator. During the operation, the manipulator is often present in the body, and it is difficult for the operator to visually observe the runaway or malfunction of the manipulator. Therefore, in this case, the detection of the runaway or malfunction is easily delayed, and the manipulator cannot be stopped instantaneously immediately after the runaway or malfunction occurs. Even if the surgeon recognizes the runaway or malfunction of the manipulator as soon as possible and activates the switch instantaneously, the servomotor will be stopped after that, but the manipulator will not operate due to its inertia. Will be stopped slightly later than when stopped. That is, when a predetermined runaway force acts, the manipulator cannot be stopped instantaneously. This is a serious problem for a manipulator inserted into a body having a narrow operating range, and a delay in stopping the manipulator may cause damage to body tissue.
[0005]
[Object of the invention]
The present invention has been devised in view of such a problem, and an object thereof is to provide a medical robot capable of instantaneously automatically stopping the medical robot when the medical robot runs away or malfunctions. To provide a safety control system.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a medical robot safety control system including an operation actuator for operating a predetermined movable unit and an emergency stop unit for stopping driving of the operation actuator in an emergency.
The operation actuator is configured by a cylinder device using an incompressible liquid as a working fluid,
The emergency stop means determines whether or not an abnormal operation has occurred in the movable unit, and stops the supply or discharge of the incompressible liquid to the cylinder device when the abnormal operation occurs. Has been adopted. According to such a configuration, the occurrence of an abnormal operation of the movable portion can be determined by the emergency stop means, and the cylinder device that operates the movable portion can be automatically stopped. In addition, since incompressible liquid is used as the fluid used in the cylinder device, when the supply or discharge of the liquid to the cylinder device is stopped, the liquid filled in the cylinder device is elastically compressed or expanded. Is suppressed, and the operation of the movable portion due to inertia due to the compression or expansion is regulated, and the braking effect of the movable portion can be enhanced. Therefore, after the supply or discharge of the fluid to the cylinder device is stopped, the operation due to inertia or the like can be eliminated and the movable portion can be stopped instantaneously. In other words, no matter what amount of runaway force acts, the possible portion can be instantaneously stopped without any limit.
[0007]
The emergency stop means according to the present invention is such that the emergency stop means detects a state of operation of the movable part, a switching valve provided in the liquid flow path connected to the cylinder device, A switching control unit for controlling the switching operation,
The switching valve has an allowance position that allows supply or discharge of the fluid to the cylinder device, and a shutoff position that shuts off the supply or discharge,
The switching control unit determines whether or not the operation of the movable unit is abnormal based on the detection value of the state detection unit, and when it is determined that the operation of the movable unit is abnormal, the switching valve It is preferable to adopt a configuration in which control is performed so as to switch from the allowable position to the cutoff position. With this configuration, the above object can be achieved with a relatively simple configuration.
[0008]
In this specification, the term “incompressible liquid” is used as a general term for water and a liquid having substantially the same compressibility (expansion) as the water.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 is a conceptual diagram of a medical robot to which the safety control system according to the present embodiment is applied. In this figure, a medical robot 10 is a robot used for performing a minimally invasive surgery that does not require a large incision, and has a manipulator 11 as a movable part inserted into a human body, and holding the manipulator 11. In addition to displacing the attitude of the manipulator 11, the manipulator 11 includes a manipulator driving device 12 supported by a robot arm (not shown).
[0011]
The manipulator 11 is a manipulator for expanding an insertion path of a surgical instrument manipulator (not shown) provided with a scalpel, forceps, an endoscope, and the like on a distal end side so as to easily insert the manipulator into the body. It can be moved in a predetermined space by the operation of (not shown). As shown in FIG. 2, the manipulator 11 has a multi-joint structure spatula shape in which a plurality of elongated piece-shaped forming members 14 are connected in series, and each forming member 14 is not particularly limited. Are connected to the adjacent forming member 14 so as to be relatively displaceable in the vertical direction and the short width direction in FIG. As shown in FIG. 1, two wires W extending toward the manipulator driving device 12 are fixed to each forming member 14, and an arbitrary wire W is pulled from the manipulator driving device 12. Thus, the forming member 14 connected to the wire W is bent and displaced, so that the posture of the manipulator 11 changes. In FIG. 1, the wires W are exposed on both upper and lower sides of each forming member 14 for convenience of description, but in actuality, the manipulator drive is performed through grooves (not shown) formed inside each forming member 14. It extends to the device 12 side, and is hardly exposed to the outside as shown in FIG.
[0012]
As shown in FIG. 1, the manipulator driving device 12 is a device that changes the attitude of the manipulator 11 by pulling and relaxing the wire W, and includes a pulling mechanism 16 for pulling the wire W and the like. And a power means 17 for powering the traction mechanism 16. In FIG. 1, the manipulator driving device 12 is conceptually shown, and various shapes, structures, components, and the like can be adopted as long as the same operation is achieved.
[0013]
The pulling mechanism 16 includes a plurality of winding units 19 provided for the number of the wires W and winding the wires W, and a transmission unit 20 for applying a winding force to the winding units 19. .
[0014]
The take-up means 19 includes a take-up rotary shaft 22 that extends in the up-down direction in FIG. And Here, a brake pad 26 for suppressing the rotation of the winding rotary shaft 22 and a pneumatic cylinder 27 for moving the brake pad 26 are disposed on the upper end side of the winding rotary shaft 22 in FIG. The brake pad 26 moves between a lock position where rotation of the take-up rotary shaft 22 is disabled and a free position where rotation of the take-up rotary shaft 22 is permitted by driving the pneumatic cylinder 27. . The pulley 23 is provided such that one end of the wire W is fixed and the wire W can be wound by rotation of the winding rotary shaft 22.
[0015]
The transmission means 20 includes a transmission rotation shaft 29 extending in the left-right direction in FIG. 1 and rotatably supported, a worm gear 31 and a pinion gear 32 provided to be rotatable integrally with the transmission rotation shaft 29, and a pinion gear. 32 and a rack 33 that moves up and down by the power from the power unit 17. The worm gears 31 are provided by the number of the winding rotary shafts 22 and can mesh with the gears 24 of the respective winding rotary shafts 22. Therefore, when the rack 33 moves up and down, the pinion gear 32 rotates, whereby the transmission rotation shaft 29 and the worm gear 31 rotate integrally, the gear 24 meshed with the worm gear 31 rotates, and the winding rotation shaft 22 and The pulley 23 rotates. At this time, the winding rotary shaft 22 in which the brake pad 26 is in the lock position is not rotated, and only the winding rotary shaft 22 in which the brake pad 26 is in the free position is rotated.
[0016]
The power unit 17 includes a first hydraulic cylinder 35 (cylinder device) as an operation actuator for operating the manipulator 11 by moving the rack 33 up and down, and water used as fluid for the first hydraulic cylinder 35. A second hydraulic cylinder 36 serving as a power for supplying or discharging, an ultrasonic motor 37 connected to the second hydraulic cylinder 36 with a ball screw (not shown) or the like to drive the second hydraulic cylinder 36; An operation control unit 39 that controls the attitude displacement operation of the manipulator 11 by controlling the driving of the cylinder 27 and the ultrasonic motor 37, and an emergency stop unit 40 that stops driving of the first hydraulic cylinder 35 in a predetermined emergency. It is comprised including.
[0017]
As shown conceptually in FIG. 3, the first and second hydraulic cylinders 35 and 36 are communicated by upper and lower two locations in FIG. 3 by first and second flow paths 42 and 43. For this reason, when the piston 36A of the second hydraulic cylinder 36 is pushed downward in FIG. 3 by the driving of the ultrasonic motor 37 from the state of FIG. The air is supplied into the first hydraulic cylinder 35 through the passage 43, and the piston 35A of the first hydraulic cylinder 35 is pushed upward in FIG. 3 to raise the rack 33. On the other hand, when the piston 36A of the second hydraulic cylinder 36 is pushed upward in FIG. 3 from the state of FIG. 3, the water in the first hydraulic cylinder 35 is discharged to the second flow passage 36 and the first hydraulic cylinder 35 is discharged. The piston 35A of the hydraulic cylinder 35 is pushed downward in FIG. 3, and the rack 33 descends. Instead of the first and second hydraulic cylinders 35 and 36, it is also possible to use a cylinder device that uses another incompressible fluid such as physiological saline as a working fluid.
[0018]
As shown in FIG. 1, the operation control unit 39 drives the pneumatic cylinder 27 at a desired location according to a command from the operating unit 45 operated by the operator to set the corresponding brake pad 26 to the free position. At the same time, the ultrasonic motor 37 is rotationally driven to perform control so that a desired portion of the manipulator 11 is bent and displaced. Here, the attitude of the manipulator 11 is feedback-controlled based on a detection value of a potentiometer (not shown) that measures the rotation angle of each winding rotary shaft 22. Note that other detailed configurations are not the gist of the present invention, and thus description thereof is omitted.
[0019]
The emergency stop means 40 is configured to shut off the flow of water between the first and second hydraulic cylinders 35 and 36 when an abnormal operation occurs in the manipulator 11. That is, the emergency stop unit 40 includes a state detection unit 47 that detects an operation state of the manipulator 11, three-port electromagnetic switching valves 49 and 50 provided in the first and second flow paths 42 and 43, respectively. A third flow path 52 connected between the electromagnetic switching valves 49 and 50; and a switching control unit 54 for controlling the switching operation of the electromagnetic switching valves 49 and 50.
[0020]
The state detection section 47 is configured by a tension sensor provided for each wire W, and detects the tension of each wire W.
[0021]
As shown in FIG. 3, the electromagnetic switching valves 49 and 50 have an allowable position for permitting water supply and drainage to the first hydraulic cylinder 35 and a shutoff position for shutting off the water supply and drainage. The solenoid-operated switching valves 49 and 50 are set at the respective allowable positions. When the electromagnetic switching valves 49 and 50 are switched to the shut-off positions from this state, the first and second flow paths 42 and 43 on the second hydraulic cylinder 36 side communicate with the third flow path 52. Then, a closed circuit including the second hydraulic cylinder 36 is formed so that supply and drainage to the first hydraulic cylinder 35 is disabled.
[0022]
The switching control unit 54 determines whether or not the operation of the manipulator 11 is abnormal based on the detection value of the state detection unit 47. If the operation of the manipulator 11 is determined to be abnormal, the electromagnetic switching valve 49 , 50 are controlled to switch from the permissible position to the shut-off position. That is, the switching control unit 54 constantly monitors the surface pressure of the manipulator 11 by obtaining the surface pressure of the manipulator 11 from the tension of each wire W detected by the state detection unit 47 using a predetermined arithmetic expression. Then, when the manipulator 11 inserted into the body is strongly pressed against tissue in the body due to runaway of the manipulator 11 due to disturbance or an erroneous operation of the operator, the surface pressure of the manipulator 11 increases. When the stored value exceeds the predetermined value, it is determined that an abnormality has occurred in the operation of the manipulator 11, and the electromagnetic switching valves 49 and 50 are controlled so as to switch from the allowable position to the shutoff position.
[0023]
Next, the operation of the medical robot 10 will be described with reference to FIGS.
[0024]
When the surgeon operates the operating means 45 to instruct the desired portion of the manipulator 11 to bend and displace in a state where all the brake pads 26 are in the lock position, the winding rotary shaft 22 corresponding to the desired portion is operated. The brake pad 26 moves from the lock position to the free position by driving the pneumatic cylinder 27. Then, the ultrasonic motor 37 is rotationally driven to drive the second hydraulic cylinder 36, and the water in the second hydraulic cylinder 36 is supplied into the first hydraulic cylinder 35 through the second flow path 43. Accordingly, the first hydraulic cylinder 35 is driven, and the rack 33 connected to the first hydraulic cylinder 35 moves upward. Then, the pinion gear 32 is rotated in accordance with the movement of the rack 33, and the transmission rotation shaft 29 and the worm gear 31 are rotated accordingly. Then, only the winding rotary shaft 22 corresponding to the desired portion where the brake pad 26 is in the free position is rotated via the gear 24 meshing with the worm gear 31, and the wire W is wound on the pulley 23. As a result, the wire W is pulled toward the manipulator driving device 12, and the forming member 14 of the manipulator 11 connected to the wire W is bent and displaced at a predetermined angle and in a predetermined direction with respect to the adjacent forming member 14, so that the manipulator 11 The posture will be displaced.
[0025]
When the manipulator 11 is displaced in its posture or moved as a whole, the surface of the manipulator 11 inserted into the body is strongly pressed against the tissue in the body due to runaway of the manipulator due to disturbance or erroneous operation of the operator, and the like. When the surface pressure exceeds a predetermined value stored in advance, the electromagnetic switching valves 49 and 50 each switch from the allowable position to the shutoff position. Then, the water discharged from the second hydraulic cylinder 36 is returned to the second hydraulic cylinder 36 from the middle of the second flow path 43 through the third flow path 52 and the first flow path 42. That is, the supply of water to the first hydraulic cylinder 35 stops. As a result, the driving of the first hydraulic cylinder 35 is stopped instantaneously, and the posture displacement operation of the manipulator 11 in conjunction therewith is also instantaneously stopped. That is, in this case, since the fluid that drives the first hydraulic cylinder 35 is incompressible water, when the driving of the first hydraulic cylinder 35 is stopped, the inertial motion of the manipulator 11 due to the compression of the fluid and the like. Is performed, and the manipulator 11 stops quickly when the driving of the first hydraulic cylinder 35 is stopped.
[0026]
In general, the medical robot 10 has the operation control unit 39 for performing active control and the switching control unit 54 for performing passive control independently arranged, and switches the active control system controlled by the operation control unit 39. The passive control system controlled by the control unit 54 monitors the active control system, and the passive control system suppresses runaway or malfunction of the active control system.
[0027]
Therefore, according to such an embodiment, when an abnormality occurs in the operation of the manipulator 11 inserted into the body due to runaway of the manipulator 11 due to disturbance or an erroneous operation of the operator, the state is detected as soon as possible. , The manipulator 11 can be automatically stopped instantaneously.
[0028]
In addition, after the attitude displacement operation of the manipulator 11 is stopped due to the abnormal operation, each pneumatic cylinder 27 is driven under the control of the operation control unit 39 to move all the brake pads 26 from the lock position to the free position. It may be. In this way, all the wires W connected to the manipulator 11 are in an unconstrained state, and all the bending portions of the manipulator W can be freely displaced, so that the operator can easily pull out the manipulator 11 from the body.
[0029]
Further, another element that can determine the abnormal operation of the manipulator 11 may be detected, and the manipulator 11 may be automatically stopped based on the detected value.
[0030]
Further, instead of the second hydraulic cylinder 26 and the ultrasonic motor 37 in the above-described embodiment, it is also possible to use another actuator such as a pump for supplying and discharging water to and from the first hydraulic cylinder 25.
[0031]
In addition, the present invention can be applied to the operation of various medical robots including the operation of other manipulators.
[0032]
In addition, each configuration in the present invention is not limited to the illustrated configuration example, and various design changes are possible as long as substantially the same operation is achieved.
[0033]
【The invention's effect】
As described above, according to the present invention, the medical robot can be automatically stopped instantaneously when the medical robot runs away or malfunctions.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a medical robot to which a safety control system according to an embodiment is applied.
FIG. 2 is a schematic perspective view of a manipulator.
FIG. 3 is a schematic diagram for explaining emergency stop means.
[Explanation of symbols]
10 Medical robot 11 Manipulator (movable part)
35 1st hydraulic cylinder (actuator for operation)
40 emergency stop means 47 state detection unit 42 first flow path (flow path)
43 Second flow path (flow path)
49 Solenoid switching valve (switching valve)
50 Solenoid switching valve (switching valve)

Claims (2)

In a safety control system for a medical robot including an operation actuator for operating a predetermined movable unit and an emergency stop unit for stopping driving of the operation actuator in an emergency,
The operation actuator is configured by a cylinder device using an incompressible liquid as a working fluid,
The emergency stop means determines whether or not an abnormal operation has occurred in the movable unit, and stops the supply or discharge of the incompressible liquid to the cylinder device when the abnormal operation occurs. Safety control system for medical robots. The emergency stop means includes a state detection unit that detects an operation state of the movable unit, a switching valve provided in the liquid flow path connected to the cylinder device, and a switching control unit that controls a switching operation of the switching valve. With
The switching valve has an allowance position that allows supply or discharge of the fluid to the cylinder device, and a shutoff position that shuts off the supply or discharge,
The switching control unit determines whether or not the operation of the movable unit is abnormal based on the detection value of the state detection unit, and when it is determined that the operation of the movable unit is abnormal, the switching valve 2. The safety control system for a medical robot according to claim 1, wherein control is performed to switch from the allowable position to the cutoff position.

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