Patent Publication Number: US-2018036090-A1

Title: Medical manipulator system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application based on a PCT Patent Application No. PCT/JP2016/051833, filed on Jan. 22, 2016, the entire content of which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a medical manipulator system. 
     Description of the Related Art 
     Medical manipulator systems that perform a surgical operation by operating a plurality of arms have been known hitherto. For example, United States Patent Application, Publication No. 2013/325031 discloses a medical manipulator system that has a plurality of arms capable of mounting a surgical tool and that can move the plurality of arms such that the surgical tool is swung with an incision position for introducing the surgical tool into the body as a center (remote center). 
     The medical manipulator system disclosed in United States Patent Application, Publication No. 2013/325031 can automatically or manually move the arms while maintaining the position of the remote center. 
     SUMMARY 
     One aspect of the invention is a medical manipulator system including a first manipulator having a joint group; a first manipulation unit that issues a command for manipulating the first manipulator; a control unit that receives the command and controls the first manipulator according to one operation mode among a plurality of operation modes; a contact detection unit that detects that the first manipulator and an obstacle have come into contact with each other; and a second manipulator capable of operating independently from or in cooperation with the first manipulator. The joint group includes one or more joints belonging to a first group, and one or more joints belonging to a second group. The plurality of operation modes includes a first mode in which the first manipulator is controlled such that the first manipulator moves along a first movement path on which the first manipulator is operated only using the joints belonging to the first group, a second mode in which the first manipulator is controlled such that the first manipulator moves along the second movement path on which the first manipulator is moved using the joints belonging to the first group and the joints belonging to the second group, and a third mode in which the first manipulator is operated so as to cancel a contact state between the first manipulator and the obstacle when the contact detection unit detects the contact between the first manipulator and the obstacle. The control unit includes a position recognition unit that recognizes positions of the first manipulator and the second manipulator, an interference prediction unit that predicts whether or not the first manipulator interferes with the second manipulator in a case in which the first manipulator is moved along the first movement path, and a mode selection unit that selects any one of the first mode and the second mode such that the first mode is selected in a case in which the interference prediction unit predicts that the first manipulator does not interfere with the second manipulator, and the second mode is selected in a case in which the interference prediction unit predicts that the first manipulator interferes with the second manipulator, and selects one mode from the plurality of operation modes so as to shift from the first mode or the second mode to the third mode in a case in which the contact detection unit detects the contact between the first manipulator and the obstacle while the control unit is operating in the first mode or the second mode. The control unit sets a path for detouring the position of the second manipulator as the second movement path in the second mode. 
     The joints belonging to the second group may include a redundant joint that has a redundant relationship with the joints belonging to the first group. 
     The control unit may include, as a control procedure of the first manipulator in the third mode, a command stop step of stopping the control of the first manipulator based on the command, a movement amount calculation step of calculating a movement amount of the first manipulator for canceling a contact state between the first manipulator and the obstacle, a movement step of moving the first manipulator by the movement amount calculated in the movement amount calculation step, and a return step of shifting the third mode to a mode which is a mode before shift to the third mode and is one of the first mode and the second mode. The control unit may control the first manipulator according to the control procedure of the first manipulator in the third mode. 
     The first manipulator may further include a second manipulation unit that is capable of operating the first manipulator and is different from the first manipulation unit. The control unit includes, as a control procedure of the first manipulator in the third mode, a command stop step of stopping the control of the first manipulator based on the command, and a permission step of permitting the second manipulation unit to manipulate the first manipulator. The control unit may control the first manipulator according to the control procedure of the first manipulator in the third mode. 
     The second manipulation unit may further include an end detection unit that detects end of the manipulation performed by the second manipulation unit. The control unit may further include, as a control procedure of the first manipulator in the third mode, a return step of shifting the third mode to a mode which is a mode before shift to the third mode in a case in which the end detection unit detects the end of the manipulation performed by the second manipulation unit. The control unit may control first manipulator according to the control procedure of the first manipulator in the third mode. 
     A control method of controlling a first manipulator in a medical manipulator system, includes the first manipulator having a joint group having one or more joints belonging to a first group and one or more joints belonging to a second group, a first manipulation unit that issues a command for manipulating the first manipulator, a control unit that receives the command and controls the first manipulator, and a second manipulator capable of operating independently from or in cooperation with the first manipulator. The control method includes: a first step of controlling the first manipulator such that the first manipulator moves along a first movement path on which the first manipulator is operated only using the joints belonging to the first group; a second step of determining whether or not the second manipulator is located on the first movement path; a third step of setting a path for detouring the position of the second manipulator as the second movement path in a case in which it is determined that the second manipulator is located on the first movement path in the second step, and of controlling the first manipulator using the joints belonging to the first group and the joints belonging to the second group such that the first manipulator moves along the second movement path; a fourth step of detecting contact between the first manipulator and an obstacle; and a fifth step of operating the first manipulator so as to cancel a contact state between the first manipulator and the obstacle in a case in which the contact between the first manipulator and the obstacle is detected in the fourth step. 
     In the control method, the control unit may include, as a control procedure of the first manipulator in the fifth step, a command stop step of stopping the control of the first manipulator based on the command, a movement amount calculation step of calculating a movement amount of the first manipulator for canceling a contact state between the first manipulator and the obstacle, a movement step of moving the first manipulator by the movement amount calculated in the movement amount calculation step, and a return step of shifting the fifth step to a step which is a step before shift to the fifth step and is one of the first step and the third step. The control unit may control the first manipulator according to the control procedure of the first manipulator in the fifth step. 
     In the control method, the first manipulator may further include a second manipulation unit that is capable of manipulating the first manipulator and is different from the first manipulation unit. The control unit may include, as a control procedure of the first manipulator in the fifth step, a command stop step of stopping the control of the first manipulator based on the command, and a permission step of permitting the second manipulation unit to manipulate the first manipulator. The control unit may control the first manipulator according to the control procedure of the first manipulator in the fifth step. 
     In the control method, the second manipulation unit may further include an end detection unit that detects end of the manipulation performed by the second manipulation unit. The control unit may further include, as a control procedure of the first manipulator in the fifth step, a return step of shifting the fifth step to a step that is a step before shift to the fifth step in a case in which the end detection unit detects the end of the manipulation performed by the second manipulation unit, the control unit may control the first manipulator according to the control procedure of the first manipulator in the fifth step. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view illustrating a medical manipulator system of a first embodiment of the invention. 
         FIG. 2  is a schematic view illustrating a first manipulator of the medical manipulator system. 
         FIG. 3  is a block diagram illustrating main units of the medical manipulator system. 
         FIG. 4  is a flowchart illustrating a control procedure in a control unit of the medical manipulator system. 
         FIG. 5  is a flowchart illustrating the flow of a manipulation using the medical manipulator system. 
         FIG. 6  is a view for explaining the working of the medical manipulator system. 
         FIG. 7  is a view for explaining the working of the medical manipulator system. 
         FIG. 8  is a view for explaining the working of the medical manipulator system. 
         FIG. 9  is a schematic view illustrating the first manipulator in a modification example of the medical manipulator system of the embodiment. 
         FIG. 10  is a schematic view illustrating a medical manipulator system of a second embodiment of the invention. 
         FIG. 11  is a view for explaining the working of the medical manipulator system. 
         FIG. 12  is a block diagram illustrating main units of a medical manipulator system of a third embodiment of the invention. 
         FIG. 13  is a view for explaining the working of the medical manipulator system. 
         FIG. 14  is a view for explaining the working of the medical manipulator system. 
         FIG. 15  is a block diagram illustrating main units of a medical manipulator system of a fourth embodiment of the invention. 
         FIG. 16  is a flowchart illustrating the flow of a manipulation using the medical manipulator system. 
         FIG. 17  is a schematic view illustrating the first manipulator in a modification example of the medical manipulator system of the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     A first embodiment of the invention will be described.  FIG. 1  is a schematic view illustrating a medical manipulator system of the present embodiment.  FIG. 2  is a schematic view illustrating a first manipulator of the medical manipulator system.  FIG. 3  is a block diagram illustrating main units of the medical manipulator system. 
     A medical manipulator system  1  of the present embodiment illustrated in  FIG. 1  is a master-slave type manipulator system. The medical manipulator system  1  has a plurality of slave manipulators (a first manipulator  10 , a second manipulator  20 , a third manipulator  30 , a fourth manipulator  40 ), a surgical bed  50 , a manipulation unit  60 , an input processing circuit  70 , an image processing circuit  80 , a display unit  90 , and a control unit  100 . 
     The plurality of slave manipulators  10 ,  20 ,  30 , and  40  are installed in the vicinity of the surgical bed  50  on which a patient P is placed. In addition, the slave manipulators  10 ,  20 ,  30 , and  40  may be installed in the surgical bed  50 . 
     In the following, the configuration of the first manipulator  10  will be described in detail. Since the second manipulator  20 , the third manipulator  30 , and the fourth manipulator  40  have the same configuration as that of the first manipulator  10 , the detailed description hereof will be omitted. 
     As illustrated in  FIG. 2 , the first manipulator  10  has an arm  11  and an adapter  18  for attaching a surgical tool  19 . 
     The arm  11  has a link group  12 , a joint group  13 , a torque sensor  14 , an actuator  15 , and an encoder  16 . 
     The link group  12  has a plurality of links  12   a,    12   b,    12   c,    12   d,    12   e,  and  12   f.  The plurality of links  12   a,    12   b,    12   c,    12   d,    12   e,  and  12   f  are movable by respective joints (to be described below) included in the joint group  13  with pivot axes peculiar to the joints as pivot centers. The adapter  18  for attaching the surgical tool  19  is disposed on the link  12   f  located closest to a distal side among the plurality of links  12   a,    12   b,    12   c,    12   d,    12   e,  and  12   f.    
     The joint group  13  has joints  13 A 1 ,  13 A 2 , and  13 A 3  belonging to a first group (normal joint  13 A), and joints  13 B 1 ,  13 B 2 , and  13 B 3  belonging to a second group (redundant joint  13 B). 
     The joint  13 A 1 ,  13 A 2 , and  13 A 3 , which are included in the normal joint  13 A, in the joint group  13  of the first manipulator  10  become, for example, driving shafts for at least one of yawing, pitching, and rolling and are preferentially used during the operation of the first manipulator  10 . The number of joints included in the normal joint  13 A may be appropriately selected in consideration of the degrees of freedom required for the first manipulator  10 . 
     The joints  13 B 1 ,  13 B 2 , and  13 B 3 , which are included in the redundant joint  13 B, in the joint group  13  of the first manipulator  10 , have a redundant relationship with respect to the above normal joint (the joints  13 A 1 ,  13 A 2 , and  13 A 3 ), respectively. The redundant joint  13 B gives more redundant degrees of freedom than the degrees of freedom that the normal joint  13 A gives to the first manipulator  10  to the first manipulator  10 . In the present embodiment, the redundant joint  13 B is allocated to all the joints belonging to the normal joint  13 A. 
     The torque sensor  14  is a sensor that detects the magnitude of the torque applied each joint that constitutes the joint group  13 . The torque sensor  14  is connected to the control unit  100 . 
     The actuator  15  operates the joint group  13 . The actuator  15  is able to operate only the joints included in the normal joint  13 A or operate both the normal joint  13 A and the redundant joint  13 B in accordance with a control using the control unit  100 . 
     The encoder  16  detects the amount of operation of the joint group  13 . The encoder  16  is connected to the control unit  100 . Accordingly, the control unit  100  is able to recognize the amount of operation of the joint group  13 . 
     The surgical tool  19  attached to the first manipulator  10  includes an end effector  19   a  at a distal end of an elongated shaft  19   b.  The end effector  19   a  of the surgical tool  19  is operated in correspondence with the manipulation in the manipulation unit  60  by a drive unit (not illustrated) provided in the adapter  18  (refer to  FIG. 1 ). Surgical tools  29 ,  39 , and  49  attached to the other slave manipulators  20 ,  30 , and  40  may also have the same configuration as that of the above surgical tool  19 . 
     Although not described in detail, the second manipulator  20 , the third manipulator  30 , and the fourth manipulator  40  illustrated in  FIG. 1  have arms  21 ,  31 , and  41  and adapters  28 ,  38 , and  48 , respectively, like the first manipulator  10 , and the surgical tools  29 ,  39 , and  49  are capable of being connected via the adapters  28 ,  38 , and  48 . 
     As illustrated in  FIG. 1 , manipulations for actuating the plurality of slave manipulators  10 ,  20 ,  30 , and  40  and surgical tools  19 ,  29 ,  39 , and  49  are input to the manipulation unit  60 . The manipulation unit  60  has a master arm  61  configured so as to be held and manipulated by an operator with his/her hand. The amount of manipulation of the master arm  61  is detected in the input processing circuit  70 . 
     The input processing circuit  70  analyzes manipulation signals from the manipulation unit  60 , generates control signals (commands) for controlling the medical manipulator system  1  in accordance with analysis results of the manipulation signal, and inputs the generated control signal to the control unit  100 . 
     The image processing circuit  80  performs various kinds of image processing for displaying image signals input from the control unit  100 , and generates display image data in the display unit  90 . 
     The display unit  90  composed of, for example, a liquid crystal display, and displays an image based on the image data generated in the image processing circuit  80  in accordance with image signals acquired via an observation instrument. 
     The control unit  100  illustrated in  FIGS. 1 and 3  is, for example, a computer configured to have a CPU, a memory, and the like. The control unit  100  stores a predetermined program for controlling the plurality of slave manipulators  10 ,  20 ,  30 , and  40 , and controls the operation of the plurality of slave manipulators  10 ,  20 ,  30 , and  40  and surgical tools  19 ,  29 ,  39 , and  49  in accordance with the control signals (commands) from the input processing circuit  70 . 
     The control unit  100  controls the plurality of slave manipulators  10 ,  20 ,  30 , and  40  in accordance with one operation mode in the plurality of operation modes. In the following, the plurality of operation modes used in a case in which the control unit  100  operates the first manipulator  10  will be described focusing on a relationship between the first manipulator  10  and the second manipulator  20 . 
     The plurality of operation modes for the control unit  100  to operate the first manipulator  10  include a first mode, a second mode, and a third mode. 
     The first mode is a mode in which the first manipulator  10  is operated only using the joints belonging to the normal joint  13 A illustrated in  FIG. 2 . In the first mode, the control unit  100  (refer to  FIG. 1 ) sets a path (first movement path) along which the first manipulator  10  can be moved only using the joints belonging to the normal joint  13 A, on the basis of an operator&#39;s manipulation on the manipulation unit  60 , and controls the first manipulator  10  such that the first manipulator  10  moves along the first movement path. In the present embodiment, a shortest path (a path in which that the amount of operation of the joint group  13  is minimized as a whole) to an arrival target position of the first manipulator  10  defined by a command generated on the basis of the manipulation in the manipulation unit  60  is adopted as a candidate for the first movement path, and the first movement path is determined as a movement path of the first manipulator  10  if any interference to be described below is not predicted. 
     The second mode is a mode in which the first manipulator  10  is operated using the joints belonging to the normal joint  13 A illustrated in  FIG. 2  and the joints belonging to the redundant joint  13 B. In the second mode, the control unit  100  (refer to  FIG. 1 ) sets a path (second movement path) along which the first manipulator  10  can be moved using both of the joints belonging to the normal joint  13 A and the joints belonging to the redundant joint  13 B, on the basis of the operator&#39;s manipulation on the manipulation unit  60 , and controls the first manipulator  10  such that the first manipulator  10  moves along the second movement path. Selection of the second movement path in the second mode is subjected to limitation according to the position of the second manipulator  20 . That is, the path set as the second movement path is set to a path that does not include the position of the second manipulator  20 . Accordingly, the second movement path is set as a path that detours the position of the second manipulator  20 . In addition, setting of the second movement path in the second mode is performed such that the first manipulator  10  can be moved without coming into contact with the second manipulator  20 , also in consideration of the shape of the arm  21  of the second manipulator  20 . 
     The third mode is a mode in which the first manipulator  10  is operated so as to cancel a contact state with an obstacle when the torque sensor  14  (refer to  FIGS. 2 and 3 ) has detected the contact between the first manipulator  10  and the obstacle. In the present embodiment, in the third mode, the control unit  100  moves the first manipulator  10  in a direction in which the first manipulator  10  is separated from the obstacle. 
     Next, the configuration of the control unit  100  will be described. As illustrated in  FIG. 3 , the control unit  100  has a position recognition unit  101 , a redundant control use determination unit  102 , a return operation determination unit  105 , a mode selection unit  107 , and a drive signal generation unit  108 . In the present embodiment, the program stored in the control unit  100  includes a program for making the control unit  100  function as the position recognition unit  101 , the redundant control use determination unit  102 , the return operation determination unit  105 , the mode selection unit  107 , and the drive signal generation unit  108 . 
     The position recognition unit  101  recognizes the positions of the first manipulator  10  and the second manipulator  20 . The positions of the first manipulator  10  and the second manipulator  20  are stored in the control unit  100  as coordinates in a coordinate system based on a predetermined origin in the medical manipulator system  1 . In addition to the positions of the first manipulator  10  and the second manipulator  20 , the position recognition unit  101  of the present embodiment may recognize the postures of the first manipulator  10  and the second manipulator  20 . 
     The redundant control use determination unit  102  has an interference prediction unit  103  and an interference avoidance operation setting unit  104 . The redundant control use determination unit  102  determines whether or not it is necessary to shift to the second mode. Moreover, the redundant control use determination unit  102  passes information for specifying the movement path (second movement path) of the first manipulator  10  in the second mode to the mode selection unit  107  when it has been determined to shift to the second mode. 
     The interference prediction unit  103  predicts whether or not the first manipulator  10  and the second manipulator  20  interfere with each other in a case in which the first manipulator  10  is moved along the above first movement path. The interference prediction unit  103  predicts that the first manipulator  10  and the second manipulator  20  may interfere with each other in a case in which the second manipulator  20  is located on the first movement path. The interference prediction unit  103  predicts that the first manipulator  10  and the second manipulator  20  do not interfere with each other in a case in which the second manipulator  20  is located out of the first movement path. For example, in the present embodiment, the interference prediction unit  103  recognizes a predetermined region including coordinates showing the position of the second manipulator  20  as a region where the first manipulator  10  and the second manipulator  20  may interfere with each other, in consideration of the shape of the arm  21  of the second manipulator  20 . Then, the interference prediction unit  103  predicts that the first manipulator  10  and the second manipulator  20  may interfere with each other in a case in which at least a portion of this region is located on the first movement path. 
     The interference avoidance operation setting unit  104  calculates a movement path between a start point and an end point of the first manipulator based on a command input from the manipulation unit  60  to the control unit  100  under the conditions of detouring the position of the second manipulator  20 , and sets this movement path as the movement path (second movement path) of the first manipulator. 
     The return operation determination unit  105  detects whether or not the first manipulator  10  has come into contact with an obstacle with reference to the magnitude of a load in the torque sensor  14 , and determines whether or not it is necessary to shift to the third mode. Additionally, the return operation determination unit  105  has a return operation setting unit  106  that sets the amount of operation of the first manipulator  10  in the third mode. 
     The mode selection unit  107  selects one mode from the plurality of operation modes (the first mode, the second mode, and the third mode) for operating the control unit  100 , and the control unit  100  is operated in accordance with the selected mode. The mode selection unit  107  of the present embodiment selects the first mode in a case in which the interference prediction unit  103  has predicted if the first manipulator  10  do not interfere with the second manipulator  20 . Additionally, in a case in which the interference prediction unit  103  has predicted if the first manipulator  10  interferes with the second manipulator  20 , the redundant control use determination unit  102  determines that the shift to the second mode is required. Thus, the mode selection unit  107  selects the second mode. Moreover, in a case in which the torque sensor  14  has detected the contact between the first manipulator  10  and the obstacle while the control unit  100  is operated in the first mode or the second mode, the return operation determination unit  105  determines that shift of the third mode from the first mode or the second mode is required. Thus, the mode selection unit  107  selects the third mode. 
     In the present embodiment, in a case in which the mode selection unit  107  selects the third mode, the control unit  100  is operated in a control procedure shown in respective following steps.  FIG. 4  is a flowchart illustrating the control procedure in the control unit  100  of the medical manipulator system  1  of the present embodiment. 
     The control unit  100  illustrated in  FIG. 3  first discontinues the control of the first manipulator  10  by the first mode and the second mode (Step S 1 , a command stop step, and refer to  FIG. 4 ). In this case, the mode selection unit  107  saves a command output, based on a manipulation on the manipulation unit  60 , from the input processing circuit  70  to the control unit  100  in a buffer (primary memory) (not illustrated) of the control unit  100 . Accordingly, the control unit  100  stops the control of the first manipulator  10  based on the command. The command saved in the buffer of the control unit  100  is read at the time of return to an operation mode before the shift (first mode or second mode) from the third mode, and is subsequently used as a command to the control unit  100  for operating the first manipulator  10 . 
     After Step S 1 , the return operation setting unit  106  of the control unit  100  calculates a movement amount of the first manipulator  10  for canceling a contact state with the obstacle (Step S 2 , a movement amount calculation step). In this case, the control unit  100 , for example, calculates the movement amount of the first manipulator  10  such that the first manipulator  10  moves toward a side opposite to a direction in which the first manipulator  10  has come into contact with the obstacle. 
     After Step S 2 , the control unit  100  outputs a drive signal from the drive signal generation unit  108  to the first manipulator  10  on the basis of the movement amount calculated in Step S 2 , thereby moving the first manipulator  10  by the above movement amount (Step S 3 , a movement step). 
     After Step S 3 , the control unit  100  returns to a mode before the shift to the third mode, out of the first mode and the second mode (Step S 4 , a return step). In this case, the control unit  100  reads the command saved in the above buffer, thereby setting a movement target position of the first manipulator  10 , and controls the first manipulator  10  so as to move the first manipulator  10  to the movement target position. 
     The control unit  100  controls the operations of the slave manipulator  10  and the like, which are manipulation targets of the manipulation unit  60 , on the basis of the command. In this case, the control unit  100  is able to output drive signals to the corresponding slave manipulator  10  and the like, and operate the slave manipulator  10  and the like that are manipulation targets while the driving amounts and loads of the slave manipulator  10  and the like that are the manipulation targets, in accordance with detection signals input from the torque sensor  14  and the encoder  16  in accordance with the operations of the corresponding slave manipulator  10  and the like. 
     The control of the first manipulator  10  by the control unit  100  will be described in detail with reference to  FIG. 1  to  FIGS. 3 and 5 .  FIG. 5  is a flowchart illustrating the flow of a manipulation using the medical manipulator system  1  of the present embodiment. 
     The control unit  100  illustrated in  FIG. 3  controls the first manipulator  10  in accordance with an operation mode selected by the mode selection unit  107 . An initial operation mode in the mode selection unit  107  is the first mode (Step S 11 , refer to  FIG. 5 ). If the operation of the control unit  100  is started in the first mode in Step S 11 , the process proceeds to Step S 12 . 
     Step S 12  is a step in which the mode selection unit  107  refers to a prediction result in the interference prediction unit  103  and branches processing in accordance with the prediction result. In Step S 12 , the processing proceeds to Step S 13  if it is determined that the second manipulator  20  (refer to  FIG. 2 ) is located on the path (first movement path) set in the first mode (that is, it is predicted that the first manipulator  10  and the second manipulator  20  may interfere with each other). In Step S 12 , if it is determined that the second manipulator  20  is located out of the path (first movement path) set in the first mode, the processing returns to Step S 11  in which the first mode is continued. 
     Step S 13  is a step in which the mode selection unit  107  selects the second mode to operate the control unit  100  in the second mode. In the second mode, as the first manipulator  10  moves along the second movement path about which the position of the second manipulator  20  is taken into consideration, the first manipulator  10  is movable without interfering with the second manipulator  20 . If the operation of the control unit  100  is started in the second mode in Step S 13 , the processing proceeds to Step S 14 . 
     Step S 14  is a step in which the torque sensor  14  illustrated in  FIG. 3  refers to the magnitude of a load detected by the return operation determination unit  105 , and branches processing in accordance with magnitude of the load. In Step S 14 , in a case in which the magnitude of the load detected by the torque sensor  14  exceeds a predetermined threshold value, it is determined that the first manipulator  10  has come into contact with an obstacle not recognized by the medical manipulator system  1 , and the processing proceeds to Step S 15 . In Step S 14 , in a case in which the magnitude of the load detected by the torque sensor  14  exceeds the predetermined threshold value, it is determined that the first manipulator  10  does not come into contact with the obstacle, and the processing returns to Step S 12 . 
     Step S 15  is a step in which the mode selection unit  107  selects the third mode to operate the control unit  100  in the third mode. In the third mode, the control unit  100  moves the first manipulator  10  in a direction in which a contact state between the first manipulator  10  and the obstacle is cancelled. In Step S 15 , the first manipulator  10  is moved on the basis of the amount of operation set by the return operation setting unit  106 , and the processing returns to Step S 14 . 
     By virtue of the repetition of Step S 14  and Step S 15 , even in a case in which the amount of operation of the first manipulator  10  is insufficient and a contact state with the obstacle is not cancelled, the first manipulator  10  is moved until a contact state with the obstacle is cancelled, and the processing returns to Step S 12  after a contact state with the obstacle is cancelled. In addition, in the repetitive operation of Step S 14  and Step S 15 , the first manipulator  10  may be moved by a predetermined minute amount in the direction in which a contact state between the first manipulator  10  and the obstacle is cancelled, not limited to the amount of operation set by the return operation setting unit  106 . 
     By virtue of the respective steps from the above Step S 11  to the above Step S 15 , the control unit  100  shifts the first mode, the second mode, and the third mode, and controls the first manipulator  10  in accordance with any one operation mode among the respective operation modes. 
     In addition, in a case in which the contact between the first manipulator  10  and the obstacle has been detected during movement in the first mode, the first mode may be directly shifted to the third mode (return mode). In the case, if a contact state between the first manipulator  10  and the obstacle is cancelled, the processing proceeds to the first mode. 
     Although details are omitted, the control of the first manipulator  10  by the control unit  100  illustrated in  FIG. 1  is performed in consideration of the positions of the third manipulator  30  and the fourth manipulator  40  in addition to the position of the second manipulator  20 . Additionally, in a case in which the second manipulator  20  is a control object, the second manipulator  20  is controlled by the control unit  100  in consideration of the positions of the first manipulator  10 , the third manipulator  30 , and the fourth manipulator  40 . The same applies to a case in which the third manipulator  30  and the fourth manipulator  40  are control objects of the control unit  100 . That is, in the present embodiment, the four slave manipulators are controlled by the control unit  100  so as to avoid any interference therebetween on the basis of their mutual positions. Moreover, when the slave manipulators have come into contact with an obstacle, the slave manipulators are controlled by the control unit  100  so as to automatically cancel a contact state. 
     The working of the medical manipulator system  1  of the present embodiment will be described.  FIGS. 6 to 8  are views for explaining the working of the medical manipulator system  1  of the present embodiment. 
     The medical manipulator system  1  of the present embodiment is used in a state in which surgical tools  19  and  29  are attached to the first manipulator  10  and the second manipulator  20 . In addition, if necessary, an endoscope may be combined with the medical manipulator system  1  of the present embodiment. In this case, the operation of the endoscope may be controlled by the control unit  100 . The endoscope combined with the medical manipulator system  1  of the present embodiment images a site inside the body used as a target where a treatment is performed using surgical tools (the first surgical tool  19 , the second surgical tool  29 ) attached to the first manipulator  10  and the second manipulator  20 , and displays an endoscopic image on the display unit  90  (refer to  FIG. 1 ). 
     When using the medical manipulator system  1  illustrated in  FIGS. 1 and 6 , a treatment is performed on a treatment target site while moving the respective surgical tools  19  and  29  using the first manipulator  10  and the second manipulator  20 . Here, in order to move the first surgical tool  19  attached to the first manipulator  10 , for example, an operator performs a manipulation for moving the first surgical tool  19  on the manipulation unit  60 . Although the operator who manipulates the manipulation unit  60  views the endoscopic image displayed on the display unit  90  and grasps the position and the posture of an end effector  19   a  at a distal end of the first surgical tool  19 , the operator may not grasp the position of the arm  11  of the first manipulator  10 . In this case, the manipulation on the manipulation unit  60  is performed without taking into consideration a possibility that a portion of the arm  11  of the first manipulator  10  may interfere with the second manipulator  20 . 
     In the present embodiment, if the control unit  100  receives a command generated on the basis of the manipulation in the manipulation unit  60 , the control unit  100  calculates the first movement path for moving the first manipulator  10  only using the normal joint  13 A (refer to  FIG. 2 ) on the basis of the command. Moreover, as illustrated in the above Steps S 11  to S 15 , the control unit  100  predicts the presence/absence of any potential interference between the first manipulator  10  and the second manipulator  20 , and controls the first manipulator  10  in the first mode or the second mode. 
     In the first mode, the first manipulator  10  is moved so as to take a position and a posture according to the command only using the normal joint  13 A illustrated in  FIG. 2 . As a result, the end effector  19   a  of the first surgical tool  19  takes a position and a posture (for example, refer to  FIG. 7 ) corresponding to the manipulation on the manipulation unit  60 . The position and the posture after the movement of the end effector  19   a  of the first surgical tool  19  in this case may be obtained, for example, by performing a pivot movement with an insertion point of the first surgical tool  19  as a remote center or by performing a parallel movement or a rotational movement. 
     In the second mode, the first manipulator  10  is moved so as to detour the position of the second manipulator  20 , also using the redundant joint  13 B in addition to the normal joint  13 A illustrated in  FIG. 2 . As a result, the end effector  19   a  of the first surgical tool  19  takes a position and a posture corresponding to the manipulation on the manipulation unit  60  (refer to  FIG. 1 ). In the second mode, if the manipulation on the manipulation unit  60  is the same as the manipulation in the above first mode, the posture of the arm  11  of the first manipulator  10  after the movement is different from that in the first mode. However, the position and the posture of the end effector  19   a  of the first surgical tool  19  after the movement can be made to be substantially the same as that in the first mode. 
     In this way, in the present embodiment, even in the first mode and the second mode, any interference between the first manipulator  10  and the second manipulator  20  is not caused, and the first surgical tool  19  takes a position and a posture corresponding to the manipulation on the manipulation unit  60 . 
     Meanwhile, in the first mode and the second mode, the first manipulator  10  is moved. Thus, a possibility that the first manipulator  10  comes into contact with an obstacle X (refer to  FIG. 8 ) not recognized by the medical manipulator system  1  of the present embodiment is considered. For example, as illustrated in  FIG. 8 , a possibility that the first manipulator  10  comes into contact with an abdominal wall (obstacle X) of a patient P is considered. The position of the patient P in a space where the medical manipulator system  1  of the present embodiment is installed, the positions of medical instruments (not illustrated) other than the medical manipulator system  1 , the position of an assistant who assists in the manipulation of the medical manipulator system  1  of the present embodiment, or the like may vary during surgical operation. Thus, it is difficult to grasp all these positions in real time. 
     In the medical manipulator system  1  of the present embodiment, in a case in which the first manipulator  10  has come into contact with objects other than the object that is recognized in advance by the medical manipulator system  1 , the torque sensor  14  (refer to  FIG. 3 ) that is a contact detection unit detects the presence of the object, and the control unit  100  recognizes the object as an obstacle. Then, when the first manipulator  10  has come into contact with the obstacle, the control unit  100  shifts from the first mode or the second mode to the third mode in accordance with a selection performed by the mode selection unit  107 , and operates the first manipulator  10  so as to cancel a contact state with the obstacle. 
     In the third mode, the control unit  100  moves the first manipulator  10  such that the first manipulator  10  is separated from the obstacle (refer to Steps S 1  to S 4  illustrated in  FIG. 4 ). In the medical manipulator system  1  of the present embodiment, if the torque sensor  14  stops detecting the contact between the first manipulator and the obstacle, it is possible to automatically return from the third mode to the mode before the shift (first mode or second mode). 
     For example, in a case in which the processing has returned from the third mode to the first mode, control that moves the first manipulator  10  in the shortest path on the basis of the manipulation on the manipulation unit  60  illustrated in  FIG. 1  is performed only using the normal joint  13 A (refer to  FIG. 2 ). 
     For example, in a case in which the processing has returned from the third mode to the second mode, the control of moving the first manipulator  10  in a path about which the position of the second manipulator  20  is taken into consideration, on the basis of the manipulation on the manipulation unit  60  illustrated in  FIG. 1 , using both the normal joint  13 A and the redundant joint  13 B (refer to  FIG. 2 ), is performed. 
     As described above, according to the medical manipulator system  1  of the present embodiment, even if any of the first mode and the second mode is selected, the first surgical tool  19  can take a desired position and a desired posture without the first manipulator  10  interfering with the second manipulator  20 . Moreover, according to the medical manipulator system  1  of the present embodiment, even if the first manipulator  10  has come into contact with an obstacle during the movement of the first manipulator  10 , the first surgical tool  19  can be made to take a desired position and a desired posture by automatically canceling a contact state between the first manipulator  10  and the obstacle. As a result, according to the medical manipulator system  1  of the present embodiment, even if an obstacle is on the movement path for avoiding any interference between the arm  11  of the first manipulator  10  and the arm  21  of the second manipulator  20 , the interference can be rapidly avoided. In this way, since the interference is automatically avoided, an operator who manipulates the manipulation unit  60  can concentrate on manipulating the end effector  19   a  displayed on the display unit  90  to perform a suitable treatment on a treatment target site, without taking into consideration the presence of arms  11  and  21  or the movement and interference thereof. 
     Modification Examples 
     A modification example of the above first embodiment will be described.  FIG. 9  is a schematic view illustrating the first manipulator in the present modification example. 
     In the present modification example, as the contact detection unit, a contact sensor  17  is provided as illustrated in  FIG. 9  instead of the torque sensor  14  (refer to  FIG. 2 ) disclosed in the first embodiment. 
     The contact sensor  17  is disposed on an outer surface of the arm  11  of the first manipulator  10 . Additionally, the contact sensor  17  is connected to the control unit  100 . As an object that is not recognized at the time of starting to use the medical manipulator system  1  comes into contact with the contact sensor  17 , this object is recognized as an obstacle by the contact sensor  17  and the control unit  100 . 
     In the present modification example, in a case in which an obstacle has come into contact with the contact sensor  17 , the first manipulator  10  can be operated so as to cancel a contact state between the obstacle and the first manipulator  10 , as in the above first embodiment. 
     In addition, both the torque sensor  14  and the contact sensor  17  may be provided as the contact detection unit of the present modification example. In this case, the contact between the first manipulator  10  and the obstacle can be detected by the torque sensor  14  even in a region where the contact sensor  17  is not attached in the arm  11  of the first manipulator  10 , and the contact with the obstacle can be detected without applying the torque generated by the actuator  15  of the first manipulator  10 , in a region where the contact sensor  17  is attached. 
     Second Embodiment 
     A second embodiment of the invention will be described.  FIG. 10  is a schematic view of a medical manipulator system of the present embodiment.  FIG. 11  is a view for explaining the working of the medical manipulator system of the present embodiment. 
     The medical manipulator system  2  of the present embodiment is different from that of the above first embodiment in terms of the operation of the control unit  100  in the third mode. 
     The second manipulator  20  moves the medical manipulator system  2  of the present embodiment in addition to the first manipulator  10  in the third mode. That is, the second manipulator  20  can be operated independently from the first manipulator  10  or in cooperation with the first manipulator  10  by the control performed by the control unit  100 . 
     For example, as illustrated in  FIG. 10 , when the first manipulator  10  is moving in a direction away from the obstacle X in the third mode, as illustrated in  FIG. 11 , the second manipulator  20  is moved in a direction in which the second manipulator  20  is separated from the first manipulator  10 . Accordingly, in the present embodiment, the first manipulator  10  and the second manipulator  20  are at positions separated from each other when a contact state between the first manipulator  10  and an obstacle has been cancelled in the third mode. Thus, the probability that the first manipulator  10  interferes with the second manipulator  20  due to the movement of the first manipulator  10  after that can be lowered. 
     Additionally, the control unit  100  may analyze a command based on a manipulation that the operator has performed on the manipulation unit  60 , and may retract the second manipulator  20  out of the movement path of the first manipulator  10  after the end of the third mode. In this case, after the second mode shifts to the third mode, the processing proceeds to the first mode without returning to the second mode. 
     In the present embodiment, as the second manipulator  20  cooperates with the first manipulator  10 , the alternative of the movement path of the first manipulator  10  is expanded. Thus, a possibility that another interference is caused due to the movement of the arm  11  for avoiding any interference can be kept low. 
     Third Embodiment 
     A third embodiment of the invention will be described.  FIG. 12  is a block diagram illustrating main units of a medical manipulator system of the present embodiment.  FIGS. 13 and 14  are views for explaining the working of the medical manipulator system of the present embodiment. 
     In the medical manipulator system  3  of the present embodiment, as illustrated in  FIG. 12 , the control unit  100  is different from the above first embodiment in terms of configuration in that, when the first manipulator  10  comes into contact with an object that is not recognized at the time of starting to use the medical manipulator system  3 , the control unit has a storage unit  109  that recognizes as an obstacle of the object to store the position thereof. 
     Additionally, the control unit  100  of the medical manipulator system  3  of the present embodiment uses the coordinates of the obstacle stored in the storage unit  109  as an entry prohibition position of the first manipulator  10 . 
     For example, in a case in which the coordinates used as the entry prohibition position of the first manipulator  10  are not stored in the storage unit  109 , the first manipulator  10  is movable throughout a maximum movable range (for example, illustrated by reference sign A 1  in  FIG. 13  as an example) of the surgical tool  19  by the arm  11 . 
     Here, if the first manipulator  10  moves and comes into contact with the obstacle X (a body wall of the patient P in the present embodiment) as illustrated in  FIG. 14 , the coordinates used as the entry prohibition position of the first manipulator  10  are stored in the storage unit  109 , and a movable range of the first manipulator  10  is limited to a range A 2  up to a position where the first manipulator  10  has come into contact with the obstacle X in the maximum movable range A 1  of the surgical tool  19  by the arm  11 . Accordingly, the entry prohibition position of the first manipulator  10  is set, and the movable range of the first manipulator  10  continues being limited after the setting of the entry prohibition position. 
     In a state in which the entry prohibition position of the first manipulator  10  is set, the control unit  100  (refer to  FIG. 12 ) of the present embodiment sets the first movement path so as to detour the entry prohibition position as a control according to the first mode. In a case in which the entry prohibition position cannot be detoured (in a case in which the setting of the first movement path cannot be performed) in using only the normal joint  13 A (refer to  FIG. 2 ), a shift to the second mode is performed. Additionally, in a state in which the entry prohibition position of the first manipulator  10  is set, the control unit  100  of the present embodiment sets the second movement path so as to detour the entry prohibition position and the position of the second manipulator  20  as a control according to the second mode. 
     The storage of the coordinates of the entry prohibition position in the storage unit  109  is held until the end of use of the medical manipulator system  3 . Additionally, if necessary, by deleting the coordinates of an arbitrary entry prohibition position, the first manipulator  10  may be allowed to enter a position, which has been the entry prohibition position, again. For example, in a case in which the position of an assistant who is near the first manipulator  10  in using the medical manipulator system  3  is stored as the entry prohibition position, limitation on the movable range of the first manipulator  10  can be eliminated by deleting the coordinates from the storage unit after the assistant has moved from the position thereof. 
     The medical manipulator system  3  of the present embodiment exhibits the same effects as those of the above first embodiment. Additionally, in the present embodiment, an obstacle recognized after the start of use of the medical manipulator system  3  does not come into contact after that. Thus, useless operation of the first manipulator  10  is reduced. 
     In addition, in the present embodiment, in a case in which a big problem is not posed even if an obstacle comes into contact, the entry prohibition position may be allowed to be included in coordinates through which the first manipulator  10  passes when selecting a movement path of the first manipulator  10 . In this case, the movement path including the entry prohibition position is lower in priority than a movement path not including the entry prohibition position. Accordingly, the control unit  100  allows the first manipulator  10  to pass through the entry prohibition position only in a case in which the movement path not including the entry prohibition position cannot be set. 
     Fourth Embodiment 
     A fourth embodiment of the invention will be described.  FIG. 15  is a block diagram illustrating main units of a medical manipulator system of the present embodiment.  FIG. 16  is a flowchart illustrating the flow of a manipulation using the medical manipulator system of the present embodiment. 
     The medical manipulator system  4  (refer to  FIG. 15 ) of the present embodiment is different from the medical manipulator system  1  disclosed in the above first embodiment in terms of the contents of the third mode. 
     The third mode in the present embodiment is a direct drive mode in which the first manipulator  10  (refer to  FIG. 2 ) is not automatically operated but an assistant is allowed to operate the first manipulator  10  with his/her manual manipulation near the first manipulator  10 . 
     In the present embodiment, as illustrated in  FIG. 15 , the arm  11  and the torque sensor  14  of the first manipulator  10  serve as a second manipulation unit  62  capable of manipulating the first manipulator  10  by a method different from the manipulation unit  60 . In the present embodiment, the return operation determination unit  105  of the control unit  100  has a direct drive use determination unit  112  that determines whether or not to perform a manipulation using the second manipulation unit  62 , instead of the return operation setting unit  106 . 
     As an example, the control unit  100  of the present embodiment in a state in which the third mode is selected first saves a command in the buffer as in the first embodiment, thereby stopping the control of the first manipulator  10  based on the command (command stop step). 
     Moreover, the direct drive use determination unit  112  of the control unit  100  releases a brake for the joint group  13  of the first manipulator  10 , and permits the first manipulator  10  to operate to follow up an input in a case in which there is the input to the torque sensor  14  of the arm  11 . 
     That is, in the third mode of the present embodiment, it is a manipulation for the torque sensor  14  in which an assistant pushes and pulls or rotates the arm  11  of the first manipulator  10 . The manipulation for the torque sensor  14  is a command for moving the arm  11  with the actuator  15  in a direction in which the assistant pushes and pulls the arm  11 . In this way, in the present embodiment, the control unit  100  permits the manipulation of the first manipulator by the second manipulation unit  62  through the release of the brake of the joint group  13  and the follow-up operation control of the first manipulator  10  (permission step). 
     If necessary, the control unit  100  of the present embodiment may constrain an insertion point (a remote center RC, refer to  FIG. 2 ) of the first surgical tool  19 , may constrain some joints of the joint group  13  that connect the link group  12  of the arm  11 , or may make all the joints freely movable. 
     Additionally, as illustrated in  FIG. 15 , the control unit  100  is provided with a timer  110  that counts the time for which there is no input to the torque sensor  14 . After lapse of a given time since an input to the torque sensor  14  has disappeared, the control unit  100  determines that the manipulation for the first manipulator  10  by the assistant has ended. That is, the torque sensor  14  and a timer  110  constitutes an end detection unit  111  that detects the end of the manipulation performed by the second manipulation unit  62 . 
     After the end detection unit  111  detects the end of the manipulation performed by the second manipulation unit  62 , the control unit  100  ends the third mode to return to the first mode or the second mode (return step). 
     The operation of the medical manipulator system  4  of the present embodiment will be described in detail along a flowchart illustrated in  FIG. 16 . 
     In the present embodiment, after the start of the medical manipulator system  4 , first, a shift to the first mode is performed and the control unit  100  operates in the first mode (Step S 21 , refer to  FIG. 16 ). Subsequently, the redundant control use determination unit  102  predicts occurrence of interference between the first manipulator  10  and the second manipulator  20  (Step S 22 ). In a case in which it is predicted that there is not interference in Step S 22 , the first mode is continued (Step S 23 ) and it is determined whether or not a procedure is completed (Step S 24 ). In Step S 24 , if a procedure is being performed, the processing returns to Step S 21  in which the first mode is further continued, and if the procedure is completed, a series of steps end. 
     In a case in which it is predicted that interference may occur in the above Step S 22 , the first mode shifts to the second mode (Step S 25 ). After a shift to the second mode has been performed by Step S 25 , the first manipulator  10  is controlled by the control unit  100  so as to avoid any interference with the second manipulator  20 . 
     After Step S 25 , whether or not the first manipulator  10  has come into contact with an obstacle is detected (Step S 26 ). In Step S 26 , in a case in which the contact between the first manipulator  10  and the obstacle is not detected, the processing proceeds to Step S 27  in which the second mode is continued, and it is determined whether or not the first manipulator  10  has reached the arrival target position while avoiding any interference with the second manipulator  20  and interference avoidance has been completed (Step S 28 ). If the interference avoidance is not completed in Step S 28 , the processing returns to Step S 26 , and if the interference avoidance is completed in Step S 28 , the processing returns to Step S 21 . 
     In the above Step S 26 , in a case in which the contact between the first manipulator  10  and an obstacle is detected, the processing proceeds to Step S 29  and the second mode shifts to the third mode. The third mode in the present embodiment is a mode in which the arm  10  can be moved more directly than in a case in which the manipulation unit  60  is used in that an assistant directly moves the arm  11  of the first manipulator  10  to separate the arm from an obstacle with his/her manual manipulation. 
     While the assistant is performing the manual manipulation of the arm  11  in Step S 29 , the end detection unit  111  continues (Step S 30 ) determining whether or not the manual manipulation has ended. In the present embodiment, the end detection unit  111  determines that the manual manipulation is completed with the movement manipulation for the arm  11  not being performed for a given time or more. If the end detection unit  111  determines that the manual manipulation has been completed, the processing returns to Step S 21  in which operation is started in the first mode. 
     According to the medical manipulator system  4  of the present embodiment, even in a case in which the movement of the arm  11  for canceling a contact state between an obstacle and the first manipulator  10  is complicated and cannot be automatically cancelled, the arm  11  can be moved at the assistant&#39;s discretion. Thus, it is easy to cancel a contact state between the obstacle and the first manipulator  10 . 
     Modification Example 1 
     Modification Example 1 of the above fourth embodiment will be described.  FIG. 17  is a schematic view illustrating the first manipulator in the present modification example. 
     In the present modification example, as illustrated in  FIG. 17 , the first manipulator  10  has an indicator  120  showing how the respective joints are controlled. 
     For example, the first manipulator  10  has lamps  121  to  126  indicating three states including “constrained (not moved)”, “operated according to a manipulation performed by the first manipulation unit”, and “automatically controlled in order to avoid any interference with other manipulators” in different colors, respectively, as indicators at the respective joints of the joint group  13 . 
     The lamps  121  to  126  disposed at the respective joints of the joint group  13  make an assistant easily ascertain current states of the joints in the colors of the lamps  121  to  126 . Accordingly, in the present modification example, the assistant can ascertain which joints can move in advance, and the assistant can easily evacuate such that the arm  11  and the assistant do not come into contact with each other. 
     In addition, the indicator  120  may be provided at the other manipulators  20 ,  30 , and  40  (refer to  FIG. 1 ). 
     Modification Example 2 
     Modification Example 2 of the above fourth embodiment will be described. 
     In the present modification example, as illustrated in  FIG. 17 , the first manipulator  10  has a navigator  130  indicating in which direction it is preferable for an assistant to move the arm  11  in the third mode. Additionally, in the present modification example, a control unit (not illustrated) controls the navigator  130  on the basis of a positional relationship between the manipulator  10 , the second manipulator, and an obstacle. 
     In the present modification example, the control unit outputs, to the navigator  130 , a signal a movement recommendation direction of the first manipulator  10  so as to move the first manipulator  10  to a substantially intermediate position between an obstacle and the second manipulator on the basis of the position of the obstacle and the position of the second manipulator. 
     The navigator  130  has, for example, an arrow-shaped lamp, a liquid crystal display monitor, or the like and displays the movement recommendation direction of the first manipulator  10 , for example, by an arrow. 
     In the present modification example, the navigator  130  helps to move the first manipulator  10  to a position farthest from the obstacle and the second manipulator between the obstacle and the second manipulator. Thus, the assistant only has to move the first manipulator  10  as being displayed on the navigator  130 , so that the manipulation can be simplified. 
     Although the embodiments of the invention have been described above in detail with reference to the drawings, specific configuration is not limited to these embodiments, and design changes are also included without departing from the scope of the invention. 
     Additionally, the constituent elements illustrated in the above-described respective embodiments and respective modification examples can be suitably configured in combination.