JP4636618B2 - Simulation device, surgical robot control system using the same, and program for simulation device - Google Patents

Description

  The present invention relates to a simulation apparatus capable of estimating the stress state and deformation state of each part of an organ when an external force is applied to the organ such as an organ by a treatment tool such as a manipulator for minimally invasive surgery, and the like. The present invention relates to related apparatuses, systems, and programs.

  In recent years, attention has been focused on minimally invasive surgery that reduces the burden on a patient without requiring a large incision, and various master-slave type surgery support robots for performing this minimally invasive surgery have been researched and developed. The surgery support robot includes a manipulator that holds an endoscope, a treatment tool, and the like, a robot arm that operates the manipulator, and an operation device that gives an operation command to the robot arm by an operator. When the operator operates the operating device, the robot arm performs a desired operation in accordance with the operation.

By the way, what has the function which can measure the force concerning the treatment site | part of the front-end | tip among such a manipulator is known (refer patent document 1 etc.). This manipulator detects a reaction force against an external force applied to the organ by the treatment when the organ is treated with the working portion on the distal end side, and transmits the reaction force to the operating device on the operator side. . Therefore, in this manipulator, a force sensation as when the treatment tool is actually held is given to the operator through the operation device, and the operability of the operator can be improved.
JP 2005-103056 A

  An organ is composed of various biological tissues having different properties (material parameters) such as elastic modulus, and many organs include a caution site that cannot be overloaded, such as a blood vessel, a nerve, and a brain function region. Therefore, even if the external force applied to the organ can be grasped, at that time, it is necessary to determine whether or not the attention site is likely to be damaged by the application of the external force.

  However, in the manipulator disclosed in Patent Document 1 and the like, although the magnitude of the external force applied to the organ can be grasped by detecting the reaction force from the organ at the time of treatment, the external force is applied to each part of the organ. The magnitude of the applied stress (stress state) cannot be grasped at all. In addition, the deformation state occurring inside the organ due to the external force applied to the organ can be acquired by using a known diagnostic imaging apparatus together, but there are restrictions on the imaging surface, etc. There are limits. Therefore, in this manipulator, even if the magnitude of the external force applied to the organ can be grasped, it cannot be determined whether or not there is a possibility that the attention site is damaged by the external force applied. Must rely on the intuition of the surgeon who has received the reaction force from the operating device. This is not only a problem for the surgery support robot, but also when the surgeon actually holds the treatment tool and performs an operation.

  The present invention has been devised by paying attention to such inconveniences, and its purpose is that when an external force is applied to an organ such as an organ, the stress state and deformation state of each part constituting the organ A simulation apparatus, a control apparatus, a surgical robot control system using these, and a program for the simulation apparatus.

(1) In order to achieve the above object, the present invention models the organ based on the image data of the organ of the subject, and uses the model to each of the organ when an external force is applied to the organ. a simulation apparatus having a state estimation means for estimating the stress state of the part,
The state estimation means is a storage unit in which basic data consisting of material parameters including elastic modulus and Poisson's ratio and fracture stress data representing stress that causes the biological tissue to break are stored for each of the constituent tissues that are constituent parts of the organ And a shape position specifying unit for obtaining the shape of the organ and the position of each constituent tissue based on the image data imaged before the external force is applied, and the shape of the organ obtained by the shape position specifying unit. An element dividing unit that divides the organ into a plurality of meshes based on the basic data stored in the storage unit, the relationship between the external force and displacement is determined for each mesh, an external force vector for the organ, A rigid body equation determination unit that obtains a rigid body equation representing the relationship between the displacement vectors of the organ by a finite element method, and the external force vector is substituted into the rigid body equation before A displacement vector is obtained, and from this displacement vector, using the material parameters, a state quantity calculation unit for obtaining a stress acting on each mesh, and the stress of each mesh obtained by the state quantity calculation unit are stored in the memory. It is determined whether there is a possibility of damage of the constituent tissue by determining whether or not a predetermined threshold set for each mesh is exceeded in relation to the fracture stress data stored in the section The state determination part which performs is taken.

(4) Furthermore, based on the image data of the subject when an external force is applied to the organ, further comprising constant correction means for correcting the material parameter using a parameter identification method,
The constant correction means is a displacement vector obtained from a change vector of at least a part of the mesh obtained by the state quantity calculation unit based on the material parameter and a change in the image data when the external force is applied to the mesh. Correct the material parameters to eliminate the difference with the vector,
The rigid body equation determination unit and the state quantity calculation unit may employ a configuration in which the elastic modulus and Poisson's ratio obtained by the constant correction unit are used together.

(6) Furthermore, a control system for a surgical robot according to the present invention includes an imaging device that images a patient's organ, a manipulator inserted into the patient's body, a drive device that operates the manipulator, and the patient's Modeling the organ based on the image data of the organ, and using this model , estimating a state of each part of the organ when an external force is applied to the organ, a predetermined operation command and the simulation A control device that controls a driving device that drives the manipulator based on an estimation result by the device;
The simulation apparatus models the organ based on the image data of the organ of the subject, and uses this model to estimate the stress state of each part of the organ when an external force is applied to the organ With means,
The state estimation means is a storage unit in which basic data consisting of material parameters including elastic modulus and Poisson's ratio and fracture stress data representing stress that causes the biological tissue to break are stored for each of the constituent tissues that are constituent parts of the organ And a shape position specifying unit for obtaining the shape of the organ and the position of each constituent tissue based on the image data imaged before the external force is applied, and the shape of the organ obtained by the shape position specifying unit. An element dividing unit that divides the organ into a plurality of meshes based on the basic data stored in the storage unit, the relationship between the external force and displacement is determined for each mesh, an external force vector for the organ, A rigid body equation determination unit that obtains a rigid body equation representing the relationship between the displacement vectors of the organ by a finite element method, and the external force vector is substituted into the rigid body equation before A displacement vector is obtained, and from this displacement vector, using the material parameters, a state quantity calculation unit for obtaining a stress acting on each mesh, and the stress of each mesh obtained by the state quantity calculation unit are stored in the memory. It is determined whether there is a possibility of damage of the constituent tissue by determining whether or not a predetermined threshold set for each mesh is exceeded in relation to the fracture stress data stored in the section The state determination part which performs is taken.

  (7) Here, the apparatus further includes an elastic modulus measuring device capable of measuring an elastic modulus for each part of the organ from the outside of the body, and the simulation device uses the elastic modulus measured by the elastic modulus measuring device, A configuration in which the stress state and / or deformation state of each part of the organ is estimated can also be employed.

(8) Further, the present invention is to model the organs based on the image data of the organ of the subject, using this model, the stress state of each part of the organ when the external force is added to the organ A program for a simulation device for estimating
A storage unit in which basic data composed of material parameters including elastic modulus and Poisson's ratio, and fracture stress data representing stress leading to the destruction of living tissue are stored for each component tissue constituting the organ, and addition of the external force A shape position specifying unit that obtains the shape of the organ and the position of each constituent tissue based on the image data that has been previously imaged, and a plurality of the organs that are based on the shape of the organ obtained by the shape position specifying unit. Based on the basic data stored in the storage unit and an element dividing unit that divides the mesh, a relationship between the external force and displacement is obtained for each mesh, and an external force vector for the organ and a displacement vector of the organ A rigid body equation determination unit that obtains a rigid body equation representing a relationship by a finite element method, and obtains the displacement vector by substituting the external force vector into the rigid body equation. From this displacement vector, using the material parameters, the state quantity calculation unit for obtaining the stress acting on each mesh, and the stress of each mesh obtained by the state quantity calculation unit are stored in the storage unit. As a state determination unit that determines whether or not there is a possibility of damage to the constituent tissue by determining whether or not a predetermined threshold set for each mesh is exceeded in relation to the fracture stress data The computer of the simulation apparatus is configured to function .

(10) Further , based on the image data of the subject when an external force is applied to the organ, the computer is further functioned as constant correction means for correcting the material parameter using a parameter identification method,
The constant correction means is a displacement vector obtained from a change vector of at least a part of the mesh obtained by the state quantity calculation unit based on the material parameter and a change in the image data when the external force is applied to the mesh. Correct the material parameters to eliminate the difference with the vector,
The rigid body equation determination unit and the state quantity calculation unit employ a configuration in which the material parameter obtained by the constant correction unit is used .

  According to the present invention, when an external force is applied to an organ such as an organ, the stress state and deformation state of each part constituting the organ can be estimated from the magnitude of the external force. By doing so, it is useful for avoiding damage to an attention site of an organ that cannot be overloaded, such as blood vessels, nerves, and brain function regions.

  In particular, by configuring as described in (4) above, it is possible to more accurately calculate material parameters such as the elastic modulus and Poisson's ratio of organs that vary depending on the individual, such as the pathology of the subject, and the stress of each part of the organ The state and the deformed state can be determined more accurately, and when used for the operation support robot, severe control with a reduced safety factor becomes possible.

  In the case of the configuration as described in (7) above, the stress state and deformation state of each part of the organ can be obtained more accurately than using the elastic modulus of a general human liver that has been clarified academically. be able to.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)

  FIG. 1 shows a schematic configuration diagram of a control system for a surgical robot according to the present embodiment. In this figure, a control system 10 is a system for performing operation control on a master-slave type surgery support robot, and is an imaging device capable of imaging an organ L that is a part of a body organ of a patient P as a subject. 11, a robot main body 12 for performing a predetermined treatment on the organ L, an operating device 13 for operating the robot main body 12, and the operation of the robot main body 12 based on an operation command from the operating device 13. A control device 14 and a simulation device 16 that simulates the state of each part of the organ L when an external force is applied to the organ L from the modeled organ L of the patient P are configured.

  The imaging device 11 may be any device as long as it can image a patient's organ L before or during an operation. For example, a magnetic image resonance diagnostic device (MRI), a computed tomography device (CT scan), or an ultrasonic image diagnosis. A known device such as a device can be applied. In addition, an endoscope that is inserted into the body during laparoscopic surgery or the like may be used as the imaging device 11 as long as the part of the organ L necessary for processing to be described later can be imaged.

  The robot body 12 includes a manipulator 23 that holds a treatment tool such as forceps for treating the organ L, a robot arm 24 that holds the base side of the manipulator 23, and moves the manipulator 23 to move. And a driving device 25 including a motor (not shown) for driving the robot arm 24.

  The manipulator 23 is inserted into a cylindrical trocar T that is arranged so as to penetrate the inside and outside of the patient P, and a force sensor capable of detecting a reaction force against the force applied to the organ L at the distal end side. 27 is attached.

  The robot arm 24 and the driving device 25 employ a structure that is applied to a well-known surgery support robot, and are not the gist of the present invention, and thus detailed description thereof is omitted here.

  The operation device 13 is a so-called master manipulator, and the surgeon grasps the operation unit (not shown) while viewing the image of the organ L displayed on the monitor (not shown) so that the surgeon holds the desired direction. A known structure that allows the robot arm 24 to be operated in a desired direction by being moved is employed. Since this structure is also not the gist of the present invention, detailed description is omitted here.

  The control device 14 includes a predetermined computer, and a program for causing the computer to function as the following units is installed. That is, the control device 14 applies an external force to the organ L by the main control unit 29 for obtaining a desired operation of the manipulator 23 corresponding to the operation of the operation device 13 by the operator and the operation of the manipulator 23. Sometimes, a change control unit 30 for changing the operation of the manipulator 23 based on the state of each part of the organ L simulated by the simulation device 16 is provided.

  The simulation apparatus 16 is composed of a predetermined computer, and a program for causing the computer to function as the following means is installed. The simulation device 16 models the organ L of the patient P based on the image data from the imaging device 11, and using this model, the stress state of each part of the organ L when an external force is applied to the organ L. And state estimation means 31 for estimating the deformation state.

  The state estimation means 31 includes a storage unit 33 in which basic data including material parameters such as the elastic modulus and Poisson's ratio of an organ L designated in advance, and fracture stress data representing stress that causes the biological tissue to break down are stored. Based on the image data captured by the imaging device 11 before external force is applied to the organ L of the patient P by the manipulator 23, a shape position specifying unit 34 for determining the shape of the organ L and the position of each constituent tissue, and shape position specifying The element division unit 35 that divides the organ L into a plurality of elements based on the shape of the organ L determined by the unit 34, and the relationship between the external force and the displacement for each element based on the basic data stored in the storage unit 33. The rigid body equation determination unit 36 that obtains a rigid body equation representing the relationship between the external force vector with respect to the organ L and the displacement vector of the organ L by the finite element method and the rigid body equation The state quantity calculation unit 37 for obtaining the stress (state quantity) acting on each element from the magnitude of the external force detected by the sensor 27, and the stress obtained by the state quantity calculation unit 37 are stored in the storage unit 33. A state determination unit 38 for determining whether or not there is a possibility of damage to the constituent tissue by determining whether or not a predetermined threshold value set in relation to the fracture stress data is exceeded, and a state determination A change command unit 39 for giving a command to the change control unit 30 according to the determination in the unit 38 is provided.

  Next, processing performed by the simulation apparatus 16 of the present embodiment will be described below with reference to the flowchart of FIG. In the following, the organ L to be processed will be described as an example of the liver, but the present invention is not limited to this.

  Basic data on the elastic modulus and Poisson's ratio of a general human liver L that has been scientifically elucidated in advance is input and stored in the storage unit 33 for each portion of the liver L, that is, for each constituent tissue (step S101). . That is, here, basic data is set for each constituent tissue of the liver L such as hepatocytes (liver parenchymal cells), blood vessels, and nerves. Here, tissues such as blood vessels and nerves are caution sites that cannot be overloaded. The storage unit 33 stores, for each constituent tissue, a value that has been clarified academically as fracture stress data representing the stress that causes the biological tissue to break. Note that the elastic modulus of the liver L of the patient P measured by a known elastography apparatus (not shown) as an elastic modulus measuring apparatus can be stored in the storage unit 33. This elastography apparatus is an apparatus that applies an ultrasonic wave while applying an external force to the liver L from the body surface side, and determines the elastic modulus by using the phase shift of the reflected wave. Since it is not the gist of the invention, detailed description is omitted.

  Then, the liver L of the patient P is imaged by the imaging device 11, and the shape position specifying unit 34 sets the shape of the liver L of the patient P and the position of each constituent tissue of the liver L as follows ( Step S102). That is, based on the image data captured by the imaging device 11 before the operation, a three-dimensional shape of the liver L or a two-dimensional shape of a predetermined cross section is derived by known image processing using a computer, The position of the constituent tissue (liver parenchymal cells, blood vessels, nerves, etc.) is specified. Note that the shape of the liver L and the position of each constituent tissue may be set not by automatic processing by the shape position specifying unit 34 but by manual input by a person who visually recognizes the image data.

  Next, in the element dividing unit 35, based on the shape of the liver L obtained by the shape position specifying unit 34, the shape of the element (mesh M) in the finite element method, the number of nodes (node N) of each mesh M, and As shown in FIG. 3, each mesh M obtained by dividing the entire liver L into a plurality of parts is set by a known calculation process (step S103). In FIG. 3, in order to avoid complication of the drawing, the mesh M is described only in a partial region of the liver L, and the description of the mesh M in the remaining region is omitted.

以上の剛性方程式により、各ノードＮに作用する外力が特定できれば、各ノードＮの変位や各メッシュＭに作用する応力が算出可能となり、逆に、各ノードＮの変位が特定できれば、各ノードＮ及び肝臓Ｌ全体に作用する外力が算出可能となる。 Thereafter, the rigid body equation determination unit 36 determines a rigid body equation using the finite element method as follows (step S104). That is, first, by comparing the position of each constituent tissue of the liver L obtained by the shape position specifying unit 34 with each mesh M determined by the element dividing unit 35, each mesh M It is specified whether it falls under a constituent organization. Then, for each mesh M, the one of the corresponding tissue is selected from the elastic modulus and Poisson's ratio of the liver L stored for each constituent tissue in the storage unit 33. A relational expression between the load applied to the node N and the deformation information of the mesh M is obtained. The deformation information here indicates the displacement of the node N constituting the target mesh M and the stress and strain acting on the mesh M. Then, the stiffness equation of the entire liver L is obtained from the relational expression. Here, the stiffness equation is expressed as the following equation (1), assuming that the external force vector F acting on each node N is the overall stiffness matrix K and the displacement vector U of the node N.

If the external force acting on each node N can be identified by the above stiffness equation, the displacement of each node N and the stress acting on each mesh M can be calculated. Conversely, if the displacement of each node N can be identified, each node N And the external force acting on the entire liver L can be calculated.

  Thereafter, in the state quantity calculation unit 37, when the liver L is treated by the manipulator 23, the stress acting on each mesh M of the liver L is calculated as follows (step S105). That is, first, the reaction force detected by the force sensor 27 on the distal end side of the manipulator 23 is considered as an external force applied to the liver by the manipulator 23, and the distal end position of the manipulator 23 obtained from information from the control device 14 is taken into consideration. The position of the liver L on which the external force is applied and the direction and magnitude of the external force are obtained. Thus, the external force vector F acting on each node N is obtained, and the displacement vector U of the node N is obtained from the inverse matrix of the stiffness matrix K by the relationship of the above equation (1). When the displacement of each node N is obtained in this way, the Mises stress of each mesh M is obtained by the structural calculation using the elastic modulus and Poisson's ratio of the corresponding structural structure stored in the storage unit 33. In addition, as a stress calculated | required here, it is not limited to Mises stress, Other stress may be sufficient.

  Next, the state determination unit 38 determines whether the stress of each mesh M obtained by the state amount calculation unit 37 exceeds a threshold value based on the fracture stress data for each constituent tissue stored in the storage unit 33. (Step S106). Although the threshold value here is not particularly limited, it is set to the same level or slightly smaller than the fracture stress of the constituent tissue. Note that the state determination unit 38 may determine only the stress related to the mesh M located at a precaution site such as a blood vessel or a nerve among the stresses of each mesh M obtained by the state amount calculation unit 37. . In short, the determination as to whether or not there is a possibility of damage to the constituent tissue in the state determination unit 38 may be performed by appropriately selecting the mesh M according to the target organ L, or may be performed for the entire mesh M. .

  At this time, if at least one of the stresses of each mesh M exceeds the threshold value, the change command unit 39 gives a command to change the operation of the manipulator 23 so that the current stress state does not further increase. The control unit 30 controls the operation of the manipulator 23 by the change control unit 30 (step S107). On the other hand, when the stress of each mesh M does not exceed the threshold value, the change command by the change command unit 39 is not performed (step S108), and the manipulator by the main control unit 29 according to the operation command of the operating device 13 23 operation control is performed.

  Therefore, according to the first embodiment as described above, during the operation of the liver L using the manipulator 23 during the minimally invasive surgery, the model in the liver L is used by using the model assuming the liver L of the patient. In this case, it is possible to estimate the stress acting on the vascular part or nerve part, which is a caution part that cannot be overloaded, so that the stress acting on the liver L is not examined from the actual liver L during the operation. The effect of preventing unexpected damage to the site can be enhanced.

  The state estimating means 31 models the organ L based on the image data of the organ L of the patient P, and using this model, the stress state of each part when an external force is applied to the organ L and As long as the deformation state can be estimated, a part of the constituent elements of the present embodiment may be omitted, and as described above, the omitted part may be replaced with human data setting or the like.

Next, another embodiment of the present invention will be described. In the following description, the same reference numerals are used for the same or equivalent components and processing contents as in the first embodiment, and the description will be omitted or simplified.
(Second Embodiment)

  As shown in FIG. 4, the simulation device 42 of the present embodiment provides basic data including the elastic modulus and Poisson's ratio used in the state estimation means 31 to the actual patient P, as shown in FIG. 4. It is characterized in that a constant correction means 44 for correcting according to the state of the liver L is further added. In the present embodiment, the organ L to be processed is described as a liver, but the present invention is not limited to this.

  The initial basic data stored in advance in the storage unit 33 relates to a general human liver L, and detailed values differ depending on the pathological condition of each patient P, individual differences, and the like. Even when initial basic data is set by using the elastography apparatus (not shown), there is a limit in measuring the elastic modulus of each constituent tissue of the liver L in detail. Therefore, the simulation apparatus 42 of the present embodiment corrects the basic data from the deformed state of the liver L during the operation of the manipulator 23 to a patient-specific value, and uses the corrected basic data to perform the processing described in the first embodiment. Is supposed to do.

  The constant correction means 44 corrects the elastic modulus and Poisson's ratio stored in the storage unit 33 using an extended Kalman filter based on the image data of the patient P during operation in which an external force is applied to the liver L. ing. That is, attention is paid to the fact that the deformation of the liver L in the state where the external force is applied changes depending on the elastic modulus and Poisson's ratio of the liver even in the same external force state. The state of the liver is confirmed from the image data picked up, and the actual elastic modulus and Poisson's ratio of the patient P are corrected based on the state.

  The constant correction unit 44 is provided in the simulation apparatus 42 together with the state estimation unit 31, but may be configured differently from the state estimation unit 31. In this embodiment, the elastic modulus and Poisson's ratio are corrected using the extended Kalman filter. However, as long as the elastic modulus and Poisson's ratio can be corrected similarly in the following processing, other parameter identification methods such as the least squares method are used. It can also be used.

  Next, processing performed by the state estimation unit 42 of the second embodiment will be described below using the flowchart of FIG.

  In the present embodiment, first, as in step S101 of the first embodiment, basic data including the elastic modulus and Poisson's ratio of the human liver L is set for each constituent tissue of the liver L and input to the storage unit 33. (Step S201).

  Similarly to step S102 of the first embodiment, the liver L of the patient is imaged by the imaging device 11, and the shape position specifying unit 34 determines the shape of the liver L of the patient P and the position of each constituent tissue of the liver L. It is set (step S202).

  Next, as in step S103 of the first embodiment, the element division unit 35 sets each mesh M obtained by dividing the liver L into a plurality of parts based on the shape of the liver L obtained by the shape position specifying unit 11. (Step S203).

  Then, similarly to step S104 of the first embodiment, the rigid body equation determination unit 36 determines the first rigid body equation using the elastic modulus and Poisson's ratio stored in the storage unit 33 (step S204).

After that, as in step S105 of the first embodiment, the state quantity calculation unit 37 obtains the external force vector F acting on each node N from the detection value by the force sensor 34, and further, the rigid body equation determined in step S204. using, prompted the displacement vector _{U a} node (step S205), the stress acting is calculated for each mesh M (step S206).

Then, the constant correction means 44 uses the image processing such as known image matching from each image data of the liver L at the predetermined time t and the previous time t−1 captured by the imaging device 11, between each image data. from the difference in position of each node N in, determine the amount of displacement of each node N, the displacement vector U _B of the node N from these displacement determined (step S207).

そして、ステップＳ２０８で求められた新たな弾性率及びポアソン比を使って、前述のステップＳ２０４〜ステップＳ２０８の処理が繰り返し行われ、これにより、弾性率及びポアソン比が経時的に変化しながら、変位ベクトルＵ_Ａ，Ｕ_Ｂの差をほぼ同一にするような弾性率及びポアソン比に次第に近づく。以上の処理は、必ずしも全部のメッシュＭに対して行わなくてよく、各構成組織単位で少なくとも一つ以上のメッシュＭを抽出して行ってもよい。 Further, a constant correction means 44, and the displacement vector U _A of the node N obtained in step S205 based on the modulus stored in the storage unit 33 and Poisson's ratio, based on the actual deformation of the liver on the image data step so as to eliminate the difference between the displacement vector U _B of the node N obtained in S207, the following equation extended Kalman filter for which the Kalman gain was K _t, a new elastic modulus and Poisson's ratio for each mesh M is calculated ( Step S208).

Then, using the new elastic modulus and Poisson's ratio obtained in Step S208, the processing of Steps S204 to S208 described above is repeatedly performed, whereby the elastic modulus and Poisson's ratio change with time, and the displacement The elastic modulus and Poisson's ratio are gradually approached so that the difference between the vectors U _A and U _B is substantially the same. The above processing does not necessarily have to be performed on all the meshes M, and may be performed by extracting at least one mesh M in each structural unit.

Also, every time obtaining a displacement vector U _A at step S205, every stress acting on each mesh M obtained in step S206 by using the elastic modulus and Poisson's ratio at that time, in the state determination unit 38 and a change instruction section 39 The same processes as those in steps S106 to S108 of the first embodiment are performed. That is, it is determined whether or not the stress of each mesh M obtained in step S206 exceeds a threshold value that is an index of damage to the constituent tissue (step S210), and when the stress of the predetermined mesh M exceeds the threshold value. The change command to the change control unit 30 is performed so as not to advance the state (step S211). Otherwise, the change command to the change control unit 30 is not performed (step S212).

  Therefore, according to the second embodiment as described above, the elasticity and Poisson's ratio of the organ L set in advance from the deformation of the organ L at the time of surgery can be obtained from an actual patient without separately providing a special sensor or device. It can be modified as appropriate. Since the state quantity calculation unit 37 recalculates the stress while correcting the elastic modulus and Poisson's ratio, the accuracy of the stress acting on each mesh M increases with time.

  In the state estimation means 31 of each of the above embodiments, image data is acquired over time by the imaging device 11, the displacement of each node N is obtained from the change in these images, and the stiffness equation is obtained from the displacement vector U of the node N. May be used to determine the external force vector F acting on each node N, and the stress acting on each mesh may be determined from these external force vectors F. In this way, the force sensor 27 can be omitted.

  Further, the force sensor 27 may not be provided on the distal end side of the manipulator 23, and the installation position is not particularly limited as long as the magnitude of the external force applied to the organ L can be detected by the manipulator 23. It may be provided.

  Further, in accordance with a command from the change command unit 39, the following configuration may be used instead of or in addition to the above-described control in the change control unit 30. That is, when the stress of each mesh M exceeds a preset threshold, it may be configured to transmit to the operator through a predetermined device or mechanism that an overload is applied to the attention site of the organ L. . For example, according to a command from the change command unit 39, the operation device 13 is locked so that the operation of the operation device 13 is disabled or restricted, a warning sound is emitted from a speaker (not shown), or a warning is displayed on a monitor (not shown). It may be.

  In addition, the simulation devices 16 and 42 of each embodiment are not necessarily used in combination with a surgery support robot, and a part of the surgery tool is used in a surgery performed by a doctor or the like directly using a surgery tool without using the robot. Based on the detection values of the force sensor and the position sensor provided in the above, the state estimation means 31 obtains the stress state in the organ L during the operation, and the warning state is displayed to the operator through the warning sound and the display on the monitor as described above. It is also possible to communicate.

  Furthermore, in each of the above embodiments, the elastic modulus and Poisson's ratio are used as material parameters indicating the properties of the target organ. However, the various processes described above may be performed using other material parameters such as density and viscosity. it can.

  In addition, the configuration and processing procedure of each part of the apparatus according to the present invention are not limited to the aspect of the above-described embodiment, and various modifications are possible as long as substantially the same operation is achieved.

The schematic block diagram of the control system of the surgical robot which concerns on 1st Embodiment. The flowchart which shows the process sequence in the simulation apparatus of 1st Embodiment. The conceptual diagram of the liver for demonstrating the mesh and node on a finite element method. The schematic block diagram of the control system of the surgical robot which concerns on 2nd Embodiment. The flowchart which shows the process sequence in the simulation apparatus of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control system 11 Imaging apparatus 14 Control apparatus 16 Simulation apparatus 23 Manipulator 25 Drive apparatus 31 State estimation means 34 Shape position specific | specification part 35 Element division | segmentation part 36 Rigid body equation determination part 37 State quantity calculation part 38 State determination part 42 Simulation apparatus 44 Constant correction | amendment Means F External force vector L Organ (organ)
M mesh N node P Patient (subject)
U displacement vector

Claims (6)

Modeling the organs based on the image data of the organ of the subject, using this model, with a state estimation means for estimating the stress state of each part of the organ when the external force is added to the organ A simulation device,
The state estimation means is a storage unit in which basic data consisting of material parameters including elastic modulus and Poisson's ratio and fracture stress data representing stress that causes the biological tissue to break are stored for each of the constituent tissues that are constituent parts of the organ And a shape position specifying unit for obtaining the shape of the organ and the position of each constituent tissue based on the image data imaged before the external force is applied, and the shape of the organ obtained by the shape position specifying unit. An element dividing unit that divides the organ into a plurality of meshes based on the basic data stored in the storage unit, the relationship between the external force and displacement is determined for each mesh, an external force vector for the organ, A rigid body equation determination unit that obtains a rigid body equation representing the relationship between the displacement vectors of the organ by a finite element method, and the external force vector is substituted into the rigid body equation before A displacement vector is obtained, and from this displacement vector, using the material parameters, a state quantity calculation unit for obtaining a stress acting on each mesh, and the stress of each mesh obtained by the state quantity calculation unit are stored in the memory. It is determined whether there is a possibility of damage of the constituent tissue by determining whether or not a predetermined threshold set for each mesh is exceeded in relation to the fracture stress data stored in the section A simulation apparatus comprising: a state determination unit that performs the operation . Based on image data of the subject when an external force is applied to the organ, further comprising constant correction means for correcting the material parameter using a parameter identification method,
The constant correction means is a displacement vector obtained from a change vector of at least a part of the mesh obtained by the state quantity calculation unit based on the material parameter and a change in the image data when the external force is applied to the mesh. Correct the material parameters to eliminate the difference with the vector,
Wherein the rigid equation determining unit and the state quantity calculating section, a simulation apparatus according to claim 1, characterized in that the material parameters determined by the constant compensation unit is used. An imaging device that images a patient's organ, a manipulator inserted into the patient's body, a driving device that operates the manipulator, and the organ is modeled based on image data of the patient's organ, and the model is used. And controlling a driving device for driving the manipulator based on a predetermined operation command and an estimation result by the simulation device, and estimating a state of each part of the organ when an external force is applied to the organ. And a control device that
The simulation apparatus models the organ based on the image data of the organ of the subject, and uses this model to estimate the stress state of each part of the organ when an external force is applied to the organ With means,
The state estimation means is a storage unit in which basic data consisting of material parameters including elastic modulus and Poisson's ratio and fracture stress data representing stress that causes the biological tissue to break are stored for each of the constituent tissues that are constituent parts of the organ And a shape position specifying unit for obtaining the shape of the organ and the position of each constituent tissue based on the image data imaged before the external force is applied, and the shape of the organ obtained by the shape position specifying unit. An element dividing unit that divides the organ into a plurality of meshes based on the basic data stored in the storage unit, the relationship between the external force and displacement is determined for each mesh, an external force vector for the organ, A rigid body equation determination unit that obtains a rigid body equation representing the relationship between the displacement vectors of the organ by a finite element method, and the external force vector is substituted into the rigid body equation before A displacement vector is obtained, and from this displacement vector, using the material parameters, a state quantity calculation unit for obtaining a stress acting on each mesh, and the stress of each mesh obtained by the state quantity calculation unit are stored in the memory. It is determined whether there is a possibility of damage of the constituent tissue by determining whether or not a predetermined threshold set for each mesh is exceeded in relation to the fracture stress data stored in the section A surgical robot control system comprising: a state determination unit that performs the operation. An elastic modulus measuring device capable of measuring the elastic modulus of each part of the organ from the outside of the body;
4. The surgical robot according to claim 3 , wherein the simulation apparatus estimates a stress state and / or a deformation state of each part of the organ using the elastic modulus measured by the elastic modulus measuring apparatus. Control system. Modeling the organs based on the image data of the organ of the subject, using this model, in the organs of a program for simulation apparatus for estimating the stress state of each part when an external force is added to the organ There,
A storage unit in which basic data composed of material parameters including elastic modulus and Poisson's ratio, and fracture stress data representing stress leading to the destruction of living tissue are stored for each component tissue constituting the organ, and addition of the external force A shape position specifying unit that obtains the shape of the organ and the position of each constituent tissue based on the image data that has been previously imaged, and a plurality of the organs that are based on the shape of the organ obtained by the shape position specifying unit. Based on the basic data stored in the storage unit and an element dividing unit that divides the mesh, a relationship between the external force and displacement is obtained for each mesh, and an external force vector for the organ and a displacement vector of the organ A rigid body equation determination unit that obtains a rigid body equation representing a relationship by a finite element method, and obtains the displacement vector by substituting the external force vector into the rigid body equation. From this displacement vector, using the material parameters, the state quantity calculation unit for obtaining the stress acting on each mesh, and the stress of each mesh obtained by the state quantity calculation unit are stored in the storage unit. As a state determination unit that determines whether or not there is a possibility of damage to the constituent tissue by determining whether or not a predetermined threshold set for each mesh is exceeded in relation to the fracture stress data A program for a simulation apparatus that causes a computer of the simulation apparatus to function . Based on the image data of the subject when an external force is applied to the organ, the computer further functions as a constant correction unit that corrects the material parameter using a parameter identification method,
The constant correction means is a displacement vector obtained from a change vector of at least a part of the mesh obtained by the state quantity calculation unit based on the material parameter and a change in the image data when the external force is applied to the mesh. Correct the material parameters to eliminate the difference with the vector,
6. The program for a simulation apparatus according to claim 5, wherein the rigid body equation determination unit and the state quantity calculation unit use the material parameter obtained by the constant correction unit .

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