Patent Publication Number: US-2022227011-A1

Title: Tactile Sensor, Robot Hand, and Robot

Description:
TECHNICAL FIELD 
     The present disclosure relates to a tactile sensor, a robot hand, and a robot. 
     BACKGROUND ART 
     In Japanese Patent Application Laid-open No. 2016-205942 (patent document 1), for example, a multiaxial force sensor attached to the fingertip of a robot hand is described. 
     The multiaxial force sensor includes a sensor unit that has plural pressure sensors and a cover that covers the sensor unit. External forces input to the cover are transmitted to the pressure sensors of the sensor unit. 
     The multiaxial force sensor is designed in such a way that the cover contacts the pressure sensors as a result of enhancing the dimensional accuracy of the sensor unit and the cover. 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the conventional multiaxial force sensor, the state of contact between the pressure sensors and the cover is dependent on the dimensional accuracy of the cover and the sensor unit. 
     For this reason, processing costs end up being incurred in order to enhance the dimensional accuracy of the cover and the sensor unit. 
     It is an object of the present disclosure to provide a tactile sensor, a robot hand, and a robot that can reduce costs compared to a case where the state of contact between a cover and a detection unit is ensured by enhancing dimensional accuracy. 
     Solution to Problem 
     A tactile sensor of the present disclosure includes: a cover that is disposed so as to sandwich a base portion and covers at least part of the base portion; and a detection unit that is disposed between the base portion and the cover in a state in which it is pressed in the direction of the base portion by the cover, and detects force applied to the cover. 
     Advantageous Effects of Invention 
     According to the present disclosure, costs can be reduced compared to a case where the state of contact between a cover and a detection unit is ensured by enhancing dimensional accuracy. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram showing a robot equipped with a robot hand pertaining to a first embodiment. 
         FIG. 2  is a side view showing main parts of the robot hand pertaining to the first embodiment. 
         FIG. 3  is a perspective view showing a first finger of the robot hand pertaining to the first embodiment and shows a state in which a contact portion has been detached. 
         FIG. 4  is a sectional view showing main parts of the first finger pertaining to the first embodiment. 
         FIG. 5  is a sectional view of main parts of the first finger pertaining to the first embodiment when viewed from the front. 
         FIG. 6  is a sectional view of main parts of the first finger pertaining to the first embodiment when viewed from above. 
         FIG. 7  is a sectional view of the first finger pertaining to the first embodiment when viewed from the front at a different position from that of  FIG. 5 . 
         FIG. 8  is a sectional view of main parts of the first finger pertaining to a second embodiment when viewed from the front. 
         FIG. 9  is a sectional view of main parts of the first finger pertaining to a third embodiment when viewed from above. 
         FIG. 10  is a sectional view showing main parts of the first finger pertaining to a fourth embodiment. 
         FIG. 11  is a sectional view of main parts of the first finger pertaining to the fourth embodiment when viewed from the front. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     A first embodiment will be described below with reference to  FIG. 1  to  FIG. 7 . 
       FIG. 1  is a diagram showing a robot  10  pertaining to this embodiment. The robot  10  includes a robot body  12 , a robot arm  14  that extends from the robot body  12 , and a robot hand  16  that is provided on a distal end of the robot arm  14 . 
     The robot arm  14  is supported by the robot body  12  via a first joint  14 A, and the robot arm  14  can rotate and bend with respect to the robot body  12 . Furthermore, the robot arm  14  includes a second joint  14 B and a third joint  14 C and can bend in arbitrary directions at each of the joints  14 B,  14 C. The robot hand  16  is supported by the robot arm  14  via a fourth joint  14 D, and the robot hand  16  can rotate and bend with respect to the robot arm  14 . 
     As shown in  FIG. 1  and  FIG. 2 , the robot hand  16  includes a first finger  20  and a second finger  22 , which are disposed opposing each other, and can hold an object  24  between the two fingers  20 ,  22 . As shown in  FIG. 1  to  FIG. 3 , the first finger  20  is equipped with a tactile sensor  26 , and the second finger  22  configures an opposing member that opposes the first finger  20  equipped with the tactile sensor  26 . 
     As shown in  FIG. 1 , a controller  28  is connected to the robot body  12 . The robot body  12  outputs drive signals to actuators of the robot arm  14  and the robot hand  16  based on control signals from the controller  28  to drive the robot arm  14  and the robot hand  16 . 
       FIG. 4  is a sectional view of main parts showing the first finger  20 , and a base portion  30  configuring the first finger  20  applies force such as gripping force to the object  24  when it grips the object  24  together with the second finger  22 . The base portion  30  is equipped with the tactile sensor  26 . 
     [Tactile Sensor] 
     The tactile sensor  26  is disposed so as to sandwich the base portion  30 . The tactile sensor  26  includes a cover  40 , which covers at least part of the base portion  30 , and a detection unit (detailed below), which is disposed between the base portion  30  and the cover  40  in a state in which it is pressed in the direction of the base portion  30  by the cover  40  and detects force applied to the cover  40 . A contact portion  42  that contacts a target place of the object  24  is replaceably attached to the cover  40 . 
     [Cover] 
     As shown in  FIG. 5  and  FIG. 6 , the cover  40  includes a first side wall  46  disposed along one side face  44  of the base portion  30  which is prismatic in shape as an example, a second side wall  50  disposed along another side face  48  on the opposite side of the one side face  44 , and a connecting portion that interconnects the first side wall  46  and the second side wall  50 . As shown in  FIG. 6 , the connecting portion includes a front wall  54  disposed along a front face  52  of the base portion  30  and a rear wall  58  disposed along a back face  56 , and the front wall  54  configures a connecting wall. The front wall  54  and the rear wall  58  are continuous with the second side wall  50 , and the second side wall  50  is connected to side edges of the front wall  54  and the rear wall  58 . 
     Furthermore, as shown in  FIG. 5 , the cover  40  includes a distal end wall  62  disposed along an end face  60  of the base portion  30 , and the distal end wall  62  is supported by the first side wall  46  and the second side wall  50 . Because of this, the cover  40  is formed in the shape of a box by the first side wall  46 , the second side wall  50 , the front wall  54 , the rear wall  58 , and the distal end wall  62 . 
     (Detection Unit) 
     As shown in  FIG. 5  and  FIG. 6 , the detection unit includes a first detection unit  64  disposed between the one side face  44  and the first side wall  46  and a second detection unit  66  disposed between the other side face  48  and the second side wall  50 . Furthermore, the detection unit includes a third detection unit  68  disposed between the front face  52  and the front wall  54  (see  FIG. 6 ) and a fourth detection unit  70  disposed between the end face  60  and the distal end wall  62 . The rated loads of each of the detection units  64 ,  66 ,  68 ,  70  is lower than the rated load of the tactile sensor  26 . 
     The first detection unit  64  is disposed in the central portion of the first side wall  46  which is rectangular in shape, and the second detection unit  66  is disposed in the central portion of the second side wall  50  which is rectangular in shape. The third detection unit  68  is disposed in the central portion of the front wall  54  which is rectangular in shape, and the fourth detection unit  70  is disposed in the central portion of the distal end wall  62  which is rectangular in shape (see  FIG. 6 ). 
     Each of the detection units  64 ,  66 ,  68 ,  70  detects an applied force as an electrical change and transmits the detected electrical change to the controller  28  via a harness not shown in the drawings. Examples of electrical changes include a change in capacitance, a change in resistance value, a change in current, a change in inductance, a charge transfer, and a change in resonance frequency. Each of the detection units  64 ,  66 ,  68 ,  70  is configured by a sensor, and the sensor can be called a load sensor or a force sensor. 
     The detection units  64 ,  66 ,  68 ,  70  have identical configurations, and include rectangular sensor bodies  64 A,  66 A,  68 A,  70 A and cylindrical contacts  64 B,  66 B,  68 B,  70 B that project from the sensor bodies  64 A,  66 A,  68 A,  70 A. It will be noted that the detection units  64 ,  66 ,  68 ,  70  may be different types of detection units and may be detection units with different measurement ranges. 
     As shown in  FIG. 6 , the sensor body  64 A of the first detection unit  64  is fixed to the base portion  30  in a state in which it is housed in a recessed portion  72  for positioning formed in the one side face  44 . The distal end of the first contact  64 B of the first detection unit  64  is adhered to the cover  40  in a state in which it is inserted into a recessed portion  74  for positioning formed in the first side wall  46  of the cover  40 . 
     The sensor body  66 A of the second detection unit  66  is fixed to the base portion  30  in a state in which it is housed in a recessed portion  76  for positioning formed in the other side face  48 . The distal end of the second contact  66 B of the second detection unit  66  is adhered to the cover  40  in a state in which it is inserted into a recessed portion  78  for positioning formed in the second side wall  50  of the cover  40 . 
     The sensor body  68 A of the third detection unit  68  is fixed to the base portion  30  in a state in which it is housed in a recessed portion  80  for positioning formed in the front face  52 . The distal end of the third contact  68 B of the third detection unit  68  is adhered to the cover  40  in a state in which it is inserted into a recessed portion  82  for positioning formed in the front wall  54  of the cover  40 . 
     The sensor body  70 A of the fourth detection unit  70 , as shown in  FIG. 5 , is fixed to the base portion  30  in a state in which it is housed in a recessed portion  84  for positioning formed in the end face  60 . The distal end of the fourth contact  70 B of the fourth detection unit  70  is adhered to the cover  40  in a state in which it is inserted into a recessed portion  86  for positioning formed in the distal end wall  62  of the cover  40 . 
     Because of this, the cover  40  is supported by the base portion  30  via the detection units  64 ,  66 ,  68 ,  70 , and the walls  46 ,  50 ,  54 ,  58 ,  62  configuring the cover  40  can be integrally displaced with respect to the base portion  30 . 
     It will be noted that although in this embodiment the recessed portions  72 ,  74 ,  76 ,  78 ,  80 ,  82 ,  84 ,  86  for positioning the detection units  64 ,  66 ,  68 ,  70  are formed in the base portion  30  and the cover  40 , they are not limited to this. For example, the recessed portions  72 ,  74 ,  76 ,  78 ,  80 ,  82 ,  84 ,  86  for positioning the detection units  64 ,  66 ,  68 ,  70  may also be formed in at least either one of the base portion  30  and the cover  40 . 
     The contacts  64 B,  66 B,  68 B,  70 B of the detection units  64 ,  66 ,  68 ,  70  are configured to retract toward the sensor bodies  64 A,  66 A,  68 A,  70 A in accordance with the forces applied thereto as an example. The detection units  64 ,  66 ,  68 ,  70  measure the forces applied to the contacts  64 B,  66 B,  68 B,  70 B in accordance with the amount of retraction of the contacts  64 B,  66 B,  68 B,  70 B. 
     Because of this, as shown in  FIG. 3 , the detection units  64 ,  66 ,  68 ,  70  detect, from relative displacement of the cover  40  with respect to the base portion  30 , forces acting in a lateral direction X of the base portion  30 , forces acting in a front and rear direction Y of the base portion  30 , and forces acting in a length direction Z of the base portion  30 . 
     Additionally, as shown in  FIG. 6 , the first detection unit  64  and the second detection unit  66  are disposed in such a way that the projection direction of the first contact  64 B projecting from the first detection unit  64  and the projection direction of the second contact  66 B projecting from the second detection unit  66  are in opposite directions on a same hypothetical line  88 . 
     (Application Structure) 
     As shown in  FIG. 7 , the cover  40  includes a pressure applying structure  90  that applies pressure to the first detection unit  64  and the second detection unit  66 . 
     The pressure applying structure  90  includes width adjusting portions  92  that reduce a distance W between the first side wall  46  and the second side wall  50  and limiting portions  94  that limit the range in which the distance W is reduced by the width adjusting portions  92 . 
     Specifically, the width adjusting portions  92  are configured by bolts  100  that penetrate through holes  98  in bottom surfaces of counterbores  96  in the first side wall  46  and adjustment screw holes  102  formed in side end faces  54 A,  58 A of the front wall  54  and the rear wall  58  (see  FIG. 6 ). Furthermore, the limiting portions  94  are configured by limiting screw holes  104  formed in the side end faces  54 A,  58 A of the front wall  54  and the rear wall  58  and set screws  106  (locking screws or set screws) screwed into the limiting screw holes  104 . 
     The width adjusting portions  92  reduce the width W between the first side wall  46  and the second side wall  50  as threaded portions  100 A of the bolts  100  are screwed into the adjustment screw holes  102 . Furthermore, the limiting portions  94  adjust the amount that the set screws  106  are screwed into the limiting screw holes  104  to adjust the amount that the set screws  106  project from the side end faces  54 A,  58 A of the front wall  54  and the rear wall  58 . Additionally, the set screws  106  projecting from the side end faces  54 A,  58 A of the front wall  54  and the rear wall  58  limit movement of the first side wall  46  in the direction toward the side end faces  54 A,  58 A of the front wall  54  and the rear wall  58  to thereby limit the range in which the distance W is reduced by the width adjusting portions  92 . 
     Because of this, pressure is applied from the first side wall  46  and the second side wall  50  of the cover  40  to the contacts  64 B,  66 B of the first detection unit  64  and the second detection unit  66 , and the contacts  64 B,  66 B of the first detection unit  64  and the second detection unit  66  are kept in a state in which they are retracted a predetermined amount. At this time, pressure in the projection directions acts on the first side wall  46  and the second side wall  50  of the cover  40  from the contacts  64 B,  66 B of the first detection unit  64  and the second detection unit  66 , and this pressure becomes an application pressure. It will be noted in relation to the third detection unit  68  and the fourth detection unit  70  that application pressure may or may not be applied to them. 
     It will be noted that although in this embodiment a case using the detection units  64 ,  66  having the contacts  64 B,  66 B that retract when they are subjected to pressure is described, the detection units are not limited to this. For example, pressure-conductive rubber type or strain gauge type detection units that measure force from extension and contraction of an element when it is sandwiched between the cover  40  and the base portion  30  may also be used. 
     When using a pressure-conductive rubber type detection unit, it becomes possible to use, as the application pressure, the reaction force that occurs when the pressure-conductive rubber elastically deforms. Because of this, the pressure applying structure  90  independent of the cover  40  becomes unnecessary. 
     (Contact Portion) 
     As shown in  FIG. 4 , the contact portion  42  is configured by a rubber material formed in a tabular shape, and the contact portion  42  mitigates impact and shock between the first finger  20  and the object  24  when the first finger  20  and the second finger  22  grip the object  24 . 
     Recessed portions  108  are formed in the four corners of the contact portion  42 , and through holes  110  that penetrate to the reverse face are formed in bottom surfaces  108 A of the recessed portions  108 . Screw holes  112  are formed in places in the front wall  46  corresponding to the through holes  110 , and screws  114  inserted into the through holes  110  in the contact portion  42  are screwed into the screw holes  112 , whereby the contact portion  42  can be replaceably attached to the cover  40 . 
     (Action and Effects) 
     Next, the action and effects of this embodiment will be described. 
     In the robot  10  of this embodiment, the first finger  20  of the robot hand  16  is provided with the tactile sensor  26 . The tactile sensor  26  includes the cover  40  that is disposed so as to sandwich the base portion  30  and the detection units  64 ,  66  that are disposed between the base portion  30  and the cover  40  in a state in which they are pressed in the direction of the base portion  30  by the cover  40 . 
     For this reason, even when some dimensional error arises in the base portion  30 , the detection units  64 ,  66 , and/or the cover  40 , it becomes possible to stably ensure the state of contact between the cover  40  and the detection units  64 ,  66 . Because of this, the processing cost of the cover  40  can be kept down. 
     Consequently, the cost of the tactile sensor  26  can be reduced compared to a case where the state of contact between the cover  40  and the detection units  64 ,  66  is ensured by enhancing dimensional accuracy. 
     Furthermore, the detection units  64 ,  66  can detect force applied to the cover from the relative displacement of the cover  40  with respect to the base portion  30 . 
     Additionally, the detection unit includes the first detection unit  64  disposed between the one side face  44  and the first side wall  46  and the second detection unit  66  disposed between the other side face  48  and the second side wall  50 . Because of this, force applied from the first side wall  46  side of the cover  40  and force applied from the second side wall  50  side can be detected by the detection units  64 ,  66 . 
     Furthermore, the first detection unit  64  and the second detection unit  66  are disposed in such a way that the projection direction of the first contact  64 B projecting from the first detection unit  64  and the projection direction of the second contact  66 B projecting from the second detection unit  66  are in opposite directions on the same hypothetical line  88 . 
     For this reason, compared to a case where the projection direction of the first contact  64 B of the first detection unit  64  and the projection direction of the second contact  66 B of the second detection unit  66  are not disposed on the same hypothetical line  88 , inclination of the cover  40  can be inhibited without providing an inclination inhibiting structure. 
     Furthermore, the detection unit has the third detection unit  68  disposed between the front face  52  and the front wall  54  that configures a connecting wall. Because of this, it becomes possible to detect not only a force in the lateral direction X with respect to the base portion  30  but also a force from the front and rear direction Y. 
     Moreover, the tactile sensor  26  includes the pressure applying structure  90  that applies pressure to the detection unit from the cover  40 , and the pressure applying structure  90  includes the width adjusting portions  92  that reduce the distance W between the first side wall  46  and the second side wall  50  and the limiting portions  94  that limit the range in which the distance W is reduced by the width adjusting portions  92 . Because of this, it becomes easy to set the application pressure applied to the detection units  64 ,  66 . 
     Furthermore, the recessed portions  72 ,  74 ,  76 ,  78 ,  80 ,  82 ,  84 ,  86  for positioning the detection units  64 ,  66 ,  68 ,  70  are provided in at least either one of the base portion  30  or the cover  40 . Because of this, it becomes possible to inhibit positional misalignment of the cover  40  with respect to the detection units  64 ,  66 ,  68 ,  70 . 
     Additionally, the contact portion  42  that contacts the target place is replaceably attached to the cover  40 . For this reason, the contact portion  42  can be replaced with contact portions  42  suited to objects  24  to be gripped and the work to be performed by the robot hand  16 . 
     Specifically, when gripping a slippery object  24 , for example, a contact portion  42  having a high coefficient of friction can be attached, so that workability resulting from the robot  10  can be improved. 
     Furthermore, when the contact portion  42  deteriorates, just the contact portion  42  can be replaced. Because of this, the maintainability of the robot hand  16  is improved. 
     Second Embodiment 
       FIG. 8  is a drawing showing a second embodiment; parts identical or similar to those of the first embodiment are denoted by the same reference signs and description thereof is omitted, and only parts that are different will be described. This embodiment differs from the first embodiment in that plural buffer members  120  are disposed apart from each other between the base portion  30  and the cover  40 . 
     That is, buffer members  120  are provided between the one side face  44  of the base portion  30  and the first side wall  46 , and the buffer members  120  are disposed at the four corners of the first side wall  46 . Furthermore, buffer members  120  are provided between the other side face  48  of the base portion  30  and the second side wall  50 , and the buffer members  120  are disposed at the four corners of the second side wall  50 . Additionally, buffer members  120  are provided between the front face  52  of the base portion  30  and the front wall  54  (not shown in the drawing), and the buffer members  120  are disposed at the four corners of the front wall  54 . It will be noted that the limiting portions  94  of the pressure applying structure  90  of the first embodiment may or may not be provided. 
     Each of the buffer members  120  is formed in the shape of a cuboid, and each of the buffer members  120  is configured by elastic rubber as an example. 
     (Action and Effects) 
     In this embodiment also, the same action and effects can be obtained in regard to parts identical or similar to those of the first embodiment. 
     Furthermore, in this embodiment, the plural buffer members  120  are disposed apart from each other between the base portion  30  and the cover  40 , so wobbling and inclination of the cover  40  with respect to the base portion  30  can be inhibited. Furthermore, inclination of the cover  40  with respect to the base portion  30  can also be inhibited. 
     Third Embodiment 
       FIG. 9  is a drawing showing a third embodiment; parts identical or similar to those of the first embodiment and the second embodiment are denoted by the same reference signs and description thereof is omitted, and only parts that are different will be described. This embodiment differs from the first embodiment and the second embodiment in that the pressure applying structure  90  is configured as a result of an elastic member  130  being disposed between the cover  40  and the detection unit. 
     That is, the elastic member  130  is disposed between the first contact  64 B of the first detection unit  64  and the first side wall  46  of the cover  40 . 
     The elastic member  130  is configured by block-shaped rubber as an example, and the pressure applying structure  90  is configured utilizing the restoring force of an elastic body that is elastically deformed as a result of being pressed toward the base portion  30  by the cover  40 . 
     It will be noted that although in this embodiment the elastic member  130  is provided on the first detection unit  64 , the elastic member  130  is not limited to this and may also be provided on the second detection unit  66 . 
     Furthermore, the elastic member  130  may also be provided between the sensor bodies  64 A,  66 A of the detection units  64 ,  66  and the base portion  30 . 
     (Action and Effects) 
     In this embodiment also, the same action and effects can be obtained in regard to parts identical or similar to those of the first embodiment. 
     Furthermore, in this embodiment, the pressure applying structure  90  can be configured utilizing the restoring force of the elastic member  130  that is elastically deformed, so the pressure applying structure  90  can be simplified. 
     Fourth Embodiment 
       FIG. 10  and  FIG. 11  are drawings showing a fourth embodiment; parts identical or similar to those of the first embodiment are denoted by the same reference signs and description thereof is omitted, and only parts that are different will be described. 
     That is, the first detection unit  64  is disposed in four places apart from each other between the one side face  44  of the base portion  30  and the first side wall  46 . Furthermore, the second detection unit  66  is disposed in four places apart from each other between the other side face  48  of the base portion  30  and the second side wall  50 . 
     Additionally, the third detection unit  68  is disposed in four places apart from each other between the front face  52  of the base portion  30  and the front wall  54 . Furthermore, the fourth detection unit  70  is disposed in four places away from each other between the end face  60  of the base portion  30  and the distal end wall  62 . 
     (Action and Effects) 
     In this embodiment also, the same action and effects can be obtained in regard to parts identical or similar to those of the first embodiment. 
     Furthermore, in this embodiment, the plural detection units  64 ,  66 ,  68 ,  70  are disposed apart from each other between the faces  44 ,  48 ,  52 ,  64  of the base portion  30  and the walls  46 ,  50 ,  54 ,  62  of the cover  40 , so wobbling of the cover  40  with respect to the base portion  30  can be inhibited. Furthermore, inclination of the cover  40  with respect to the base portion  30  can also be inhibited. 
     Additionally, the plural detection units  64 ,  66  can be stably brought into contact with the cover  40  by the pressure applying structure  90 , so compared to a case where a gap is formed between any of the detection units  64 ,  66  and the cover  40 , a deterioration in detection accuracy can be inhibited. 
     It will be noted that although in the embodiments a case was described where the tactile sensor  26  is provided on the first finger  20  of the robot hand  16 , the tactile sensor  26  is not limited to this. For example, the tactile sensor  26  may also be provided on a wrist portion of the robot  10 . 
     Furthermore, the first detection unit  64  and the second detection unit  66  do not invariably need to be disposed on the same hypothetical line  88 . Moreover, the elastic member  130  configuring the pressure applying structure  90  may also be provided on the side faces  44 ,  48  on the opposite sides of the detection units  64 ,  66 . 
     Below is a description of the reference signs.
       10  Robot     12  Robot Body     16  Robot Hand     20  First Finger     22  Second Finger     24  Object     26  Tactile Sensor     30  Base Portion     40  Cover     42  Contact Portion     44  One Side Face     46  First Side Wall     48  Other Side Face     50  Second Side Wall     52  Front Face     54  Front Wall     60  End Face     62  Distal End Wall     64  First Detection Unit     64 B First Contact     66  Second Detection Unit     66 B Second Contact     72  Recessed Portions     74  Recessed Portions     76  Recessed Portions     78  Recessed Portions     80  Recessed Portions     82  Recessed Portions     84  Recessed Portions     86  Recessed Portions     88  Hypothetical Line     90  Pressure Applying Structure     92  Width Adjusting Portions     94  Limiting Portions     120  Buffer Members     130  Elastic Member   

     ADDITIONAL REMARKS 
     From this specification the following aspects are conceptualized. 
     Aspect 1 is a tactile sensor including: 
     a cover that is disposed so as to sandwich a base portion and covers at least part of the base portion; and 
     a detection unit that is disposed between the base portion and the cover in a state in which it is pressed in a direction of the base portion by the cover, and detects force applied to the cover. 
     Aspect 2 is the tactile sensor of aspect 1, 
     wherein the detection unit detects force applied to the cover from relative displacement of the cover with respect to the base portion. 
     Aspect 3 is the tactile sensor of aspect 1 or aspect 2, wherein 
     the cover includes a first side wall disposed along one side face of the base portion, a second side wall disposed along another side face on an opposite side from the one side face, and a connecting portion that interconnects the first side wall and the second side wall, and 
     the detection unit includes a first detection unit disposed between the one side face and the first side wall and a second detection unit disposed between the other side face and the second side wall. 
     Aspect 4 is the tactile sensor of aspect 3, wherein 
     the first detection unit and the second detection unit are disposed in a state in which a projection direction of a first contact projecting from the first detection unit and a projection direction of a second contact projecting from the second detection unit are opposite directions on a same line. 
     Aspect 5 is the tactile sensor of aspect 3 or aspect 4, wherein 
     the connecting portion configures a connecting wall disposed along a front face of the base portion, and 
     the detection unit further includes a third detection unit disposed between the front face and the connecting wall. 
     Aspect 6 is the tactile sensor of any of aspect 3 to aspect 5, further including a pressure applying structure that applies pressure to the detection unit from the cover. 
     Aspect 7 is the tactile sensor of aspect 6, 
     wherein the pressure applying structure includes a width adjusting portion that reduces the distance between the first side wall and the second side wall and a limiting portion that limits the range in which the distance is reduced by the width adjusting portion. 
     Aspect 8 is the tactile sensor of aspect 6, wherein the pressure applying structure is configured as a result of an elastic member being disposed at least either one of between the cover and the detection unit or between the detection unit and the base portion. 
     Aspect 9 is the tactile sensor of any of aspect 1 to aspect 8, wherein a recessed portion for positioning the detection unit is provided at at least either one of the base portion or the cover. 
     Aspect 10 is the tactile sensor of any of aspect 1 to aspect 9, wherein plural buffer members are disposed apart from each other between the base portion and the cover. 
     Aspect 11 is the tactile sensor of any of aspect 1 to aspect 10, wherein a contact portion that contacts a target place is replaceably attached to the cover. 
     Aspect 12 is a robot hand including: 
     the tactile sensor of any of aspect 1 to aspect 11; and 
     an opposing member that is disposed opposing the tactile sensor and grips an object between itself and the tactile sensor. 
     Aspect 13 is a robot including: 
     the robot hand of aspect 12; and 
     a robot body that drives the robot hand. 
     All publications, patent applications, and technical standards mentioned in this specification are incorporated by reference herein to the same extent as if each individual publication, patent application, or technical standard were specifically and individually indicated to be incorporated by reference.