Robot

Disclosed herein is a robot including a yawing actuator that allows yawing of a trunk of the robot, a pitching actuator that is arranged above the yawing actuator and is supported by the yawing actuator, the pitching actuator allowing pitching of the trunk, and a rolling actuator that is arranged in a rear of the pitching actuator and is supported by the pitching actuator, the rolling actuator allowing rolling of the trunk.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Priority Patent Application JP 2020-119284 filed Jul. 10, 2020, the entire contents of which are incorporated herein by reference.

BACKGROUND

The present disclosure relates to a robot.

Robots that can walk on two legs and robots that can walk on four legs have been and are being developed (for example, refer to JP 2003-117858A). Some of robots that can walk on two legs can move the trunk thereof. For example, a robot has been developed which allows forward tilting (pitching) of the trunk, leftward and rightward tilting (rolling) of the trunk and so forth. Such movements as just mentioned are implemented by a plurality of actuators arranged at a lower portion or the waist of the trunk.

SUMMARY

If it is tried to achieve more complicated movements of the trunk of a robot, then the number of actuators to be arranged at a lower portion of the trunk increases. For example, in order to implement yawing of the trunk, namely, twisting of the trunk, in addition to pitching of the trunk and rolling of the trunk, three actuators are used for the trunk.

If the number of actuators to be arranged on the trunk is increased, then interference of parts of the trunk becomes likely to occur. Therefore, it becomes difficult to secure a sufficient movable range for the actuators.

As another problem, there is the possibility that, if the number of actuators to be arranged on the trunk is increased, then the height of the trunk may increase and the stability in movement of the robot may be reduced.

As a further problem, also there is a problem that, if the number of actuators to be arranged on the trunk is increased, then depending upon the layout of the actuator, the size in the forward and rearward direction of the trunk of the robot increases, resulting in increase of the overall size of the robot.

According to a first mode of the present disclosure, there is provided a robot including a yawing actuator that allows yawing of a trunk of the robot, a pitching actuator that is arranged above the yawing actuator and is supported by the yawing actuator, the pitching actuator allowing pitching of the trunk, and a rolling actuator that is arranged in a rear of the pitching actuator and is supported by the pitching actuator, the rolling actuator allowing rolling of the trunk. According to this robot, the tilting range to the front of the trunk can be secured sufficiently, and also the tilting range in the leftward and rightward direction of the trunk can be secured.

According to a second mode of the present disclosure, there is provided a robot including a left leg actuator that is located at an upper portion of a left leg portion of the robot and moves the left leg portion, a right leg actuator that is located at an upper portion of a right leg portion of the robot and moves the right leg portion, a yawing actuator that is located between the right leg actuator and the left leg actuator as viewed in front elevation of the robot and allows yawing of a trunk of the robot, and at least one actuator that is arranged above the yawing actuator and allows pitching of the trunk or rolling of the trunk. According to this robot, since the location of the yawing actuator can be lowered, stability in movement of the robot can be secured.

According to a third mode of the present disclosure, there is provided a robot including a pitching actuator that allows pitching of a trunk of the robot, the pitching actuator including an electric motor, a speed reduction mechanism, and a rotation outputting section that receives rotation of the electric motor through the speed reduction mechanism, the rotation outputting section being rotatable around a first center line extending along a leftward and rightward direction of the robot, and a rolling actuator that allows rolling of the trunk, the rolling actuator including an electric motor, a speed reduction mechanism, and a rotation outputting section that receives rotation of the electric motor through the speed reduction mechanism, the rotation outputting section being rotatable around a second center line extending along a forward and rearward direction of the robot. The pitching actuator and the rolling actuator are arranged side by side in the forward and rearward direction, a center of rotation of the electric motor in the pitching actuator is located on the first center line, and a center of rotation of the electric motor in the rolling actuator is spaced in a radial direction of the electric motor from the second center line. According to this robot, the size of the trunk of the robot in the forward and rearward direction can be reduced.

It is to be noted that the structure according to the first mode may be applied to a robot that does not have the structure according to the second or third mode. Similarly, the structure according to the second mode may be applied to a robot that does not have the structure according to the first or third mode. Further, the structure according to the third mode may be applied to a robot that does not have the structure according to the first or second mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, an embodiment of the present disclosure is described with reference to the drawings. In the present specification, a robot1depicted inFIG.1and so forth is described as an example of the embodiment. Further, in the following description, directions indicated by X1and X2inFIG.1and so forth are referred to as leftward direction and rightward direction, respectively, and directions indicated by Z1and Z2in the drawings are referred to as upward direction and downward direction, respectively. Further, directions indicated by Y1and Y2in the drawings are referred to as forward direction and rearward direction, respectively.

The robot1is a robot that can walk on two legs and includes a right leg portion20R and a left leg portion20L as depicted inFIG.1. A plurality of actuators for moving the right leg portion20R and the left leg portion20L are provided on the right and left leg portions20R and20L. Each of the leg portions20R and20L includes, for example, actuators26and27at a joint of the ankle thereof and includes an actuator25at a joint of the knee thereof, and further includes actuators22,23, and24at a hip joint thereof. Further, the robot1includes a right arm portion30R and a left arm portion30L. A plurality of actuators for moving the arm portions30R and30L are provided at the arm portions30R and30L. Each of the arm portions30R and30L includes an actuator35at a joint of the elbow thereof and includes an actuator34at the upper arm thereof, and further includes actuators32and33at a joint of the shoulder. Further, the robot1includes a plurality of actuators42,43, and44for moving a head portion40thereof.

The layout of the actuators in the robot1is not limited to that depicted inFIG.1. For example, the robot1may not necessarily include the actuators42,43, and44provided at the head portion. Further, the number of actuators provided at the arm portions30R and30L may be smaller than four. Similarly, the number of actuators provided at the leg portions20R and20L may be smaller than six.

The robot1includes a plurality of, three inFIG.1, actuators11,12, and13for moving a trunk10. In particular, the robot1includes a yawing actuator11that allows yawing of the trunk10, a pitching actuator12that allows pitching of the trunk10, and a rolling actuator13that allows rolling of the trunk10. The term “yawing” represents a movement of the trunk10around an axial line extending along an upward and downward direction and the term “pitching” represents a movement of the trunk10around an axial line extending along a leftward and rightward direction. Further, the term “rolling” represents a movement of the trunk10around an axial line extending along a forward and rearward direction.

The three actuators11,12, and13are arranged at a lower portion, namely, at the waist, of the trunk10. The trunk10has, arranged at an upper portion thereof, the actuators32for moving the arm portions30R and30L and the actuator42for moving the head portion40. The actuators32are individually located at the uppermost portion of the arm portions30R and30L, and the actuator42is located at the lowermost portion among the three actuators42,43, and44.

The actuators11,12, and13for moving the trunk10individually include an electric motor, a speed reduction mechanism, and a rotation outputting section for receiving rotation of the electric motor through the speed reduction mechanism. As the electric motor, for example, a stepping motor can be used. The rotation outputting section is located at a terminal end of a torque transmission path in the actuator and is connected to some other part of the robot1, which is a movable portion of the robot1. The speed reduction mechanism can include, for example, a plurality of external tooth gears, a worm gear, and a planetary gear.

For example, as depicted inFIG.6, the yawing actuator11includes an electric motor11a, a speed reduction mechanism11b, and a rotation outputting section11cfor receiving rotation of the electric motor through the speed reduction mechanism11b. The speed reduction mechanism11bincludes a plurality of external tooth gears. The speed reduction mechanism11bis accommodated in a case11d. The case11dmay hold the electric motor11a. The electric motor11adrives around a rotation center line B11extending along the upward and downward direction. The rotation outputting section11cof the yawing actuator11rotates around a rotation center line A11extending in parallel to the rotation center line B11. A rotation outputting section12cof the pitching actuator12(refer toFIG.4B) rotates around a rotation center line A12extending along the leftward and rightward direction. A rotation outputting section13cof the rolling actuator13(refer toFIG.5B) rotates relative to an electric motor13aaround a rotation center line A13extending along the forward and rearward direction. It is to be noted that one or plural ones of the actuators11,12, and13may not include a speed reduction mechanism. In this case, the rotation outputting section may be a rotary shaft of the electric motor.

As depicted inFIG.1, the leg portions20R and20L individually include, at an uppermost portion thereof, an actuator22for moving the leg portions20R and20L. In the following description, the actuator22is referred to as a “leg actuator.” As depicted inFIG.4B, the yawing actuator11is located between the leg actuator22of the right leg portion20R and the leg actuator22of the left leg portion20L as viewed in front elevation of the robot1. As viewed in front elevation of the robot1, the position of a lower end11eof the yawing actuator11is lower than an upper end22eof the left and right leg actuators22. The remaining actuators for moving the trunk10, particularly the pitching actuator12and the rolling actuator13, are arranged above the yawing actuator11. According to this arrangement of the yawing actuator11, the location of the actuators11,12, and13for moving the trunk10can be lowered as a whole, and therefore, the position of the center of gravity of the robot1is lowered and the stability of the motion of the robot1can be enhanced.

The structure of the left and right leg actuators22is same as that of the yawing actuator11. In particular, the left and right leg actuators22individually include an electric motor22a(refer toFIG.2B), a speed reduction mechanism, and a rotation outputting section22c(refer toFIG.3A) for receiving rotation of the electric motor22athrough the speed reduction mechanism. The rotation outputting section22cof the left and right leg actuators22can rotate, for example, around a rotation center line A22(refer toFIG.3A) extending along the upward and downward direction, and the left and right leg actuators22change the orientation of the left leg portion20L and the orientation of the right leg portion20R, respectively. Also the electric motor22adrives around a rotation center line extending along the upward and downward direction. The structure of the leg actuators22is not limited to that of the robot1. For example, rotation of the electric motor22amay be transmitted to the rotation outputting section22cthrough a speed reduction mechanism including a worm gear or a speed reduction mechanism including a planetary gear.

As depicted inFIG.4B, the yawing actuator11may be located lower than the left and right leg actuators22as a whole. In particular, the position of an upper end11fof the yawing actuator11may be lower than an upper end22eof the left and right leg actuators22. In the example of the robot1, the position of the upper face of the rotation outputting section11cof the yawing actuator11is lower than the upper end22eof the electric motor22aof the leg actuators22. According to this arrangement of the yawing actuator11, since the location of the other actuators12and13for moving the trunk10can be lowered furthermore, the stability of movement of the robot1can be enhanced.

Further, as depicted inFIG.4B, the position of the lower end11eof the yawing actuator11may be lower than a lower end22fof the leg actuators22. In the example of the robot1, the position of the lower end11eof the electric motor11aof the yawing actuator11is lower than a lower face of the rotation outputting section22cof the leg actuators22. Consequently, since the location of the entire yawing actuator11is lowered, the stability of the motion of the robot1can be enhanced.

As depicted inFIG.4A, the left and right leg actuators22and the yawing actuator11are attached to a common frame61. The electric motor22aof the left and right leg actuators22is arranged on the upper side of the frame61. A lowermost portion of the electric motor11aof the yawing actuator11projects downwardly from the frame61.

As depicted inFIG.6, in the yawing actuator11, the rotation outputting section11cis spaced in a radial direction from the rotation center line B11of the electric motor11a, namely, from a rotary shaft of the electric motor11a. The speed reduction mechanism11bis arranged between the rotary shaft of the electric motor11aand the rotation outputting section11c, and transmits rotation of the electric motor11ain a reduced speed to the rotation outputting section11c. By using the actuator whose rotation outputting section is spaced away from the rotation center line of the electric motor as the yawing actuator11in this manner, the height of the yawing actuator11can be reduced. As a result, the location of the other actuators12and13for moving the trunk10can be lowered. In the robot1, the structure of the leg actuators22is same as that of the yawing actuator11. Accordingly, also the rotation outputting section22cof the leg actuators22is spaced in a radial direction from the rotation center line of the electric motor22aof the leg actuators22.

As depicted inFIG.5B, at least part of the yawing actuator11may overlap with the left and right leg actuators22as viewed in side elevation of the robot1. According to this arrangement of the actuators11and22, increase in size in the forward and rearward direction of the robot1can be prevented.

As depicted inFIG.5B, in the example of the robot1, the rotation center line A11of the rotation outputting section11cof the yawing actuator11is spaced forwardly from the electric motor11aof the yawing actuator11. On the other hand, the rotation center line A22of the rotation outputting section22cof the leg actuators22is spaced rearwardly from the electric motor22aof the leg actuators22. In other words, the direction in which the rotation outputting section11cis located with respect to the electric motor11ain the yawing actuator11, namely, the forward direction, and the direction in which the rotation outputting section22cis located with respect to the electric motor22ain the leg actuators22, namely, the rearward direction, are opposite to each other. Consequently, the locations of the electric motors11aand22aboth having a high weight are separated from each other to the front side and the rear side of the robot1, and displacement of the position of the center of gravity in the forward and rearward direction can be reduced.

As depicted inFIG.5B, the electric motors11aand22aof the two actuators11and22do not overlap with each other as viewed in side elevation of the robot1. In particular, a front face11gof the electric motor11aof the yawing actuator11is spaced from a rear face22gof the electric motor22aof the leg actuators22in the forward and rearward direction. The case11dof the yawing actuator11overlaps with the cases22dof the leg actuators22as viewed in side elevation.

As depicted inFIGS.4B and5B, the three actuators11and22placed side by side in the leftward and rightward direction are arranged such that the rotation center lines A11, B11, A22, and B22thereof are directed in the upward and downward direction. Further, the rotation center lines A11and A22of the rotation outputting sections11cand22cand the rotation center lines B11and B22of the electric motors11aand22aare spaced from each other in the forward and rearward direction. This arrangement of the three actuators11and22can suppress increase of the size of the robot1in the leftward and rightward direction.

It is to be noted that the layout of the yawing actuator11and the leg actuators22is not limited to that of the robot1. For example, while the rotation outputting section11cof the yawing actuator11is spaced rearwardly from the electric motor11aof the yawing actuator11, the rotation outputting section22cof the leg actuators22may be spaced forwardly from the electric motor22aof the leg actuators22. As another example, in the actuators11and22, the rotation outputting sections11cand22cmay be arranged on same axial lines with the electric motors11aand22a, respectively.

As a further example, in the yawing actuator11, the rotation center line B11of the electric motor11aand the rotation center line A11of the rotation outputting section11cmay be perpendicular to each other. In this case, the speed reduction mechanism11bmay include a worm gear or a helical gear. Similarly, in the leg actuators22, the rotation center line B22of the electric motor22aand the rotation center line A22of the rotation outputting section22cmay be perpendicular to each other. In this case, the speed reduction mechanism may include a worm gear or a helical gear. Also in such cases as described above, the direction in which the rotation outputting section11cof the yawing actuator11is located with respect to the electric motor11aand the direction in which the rotation outputting section22cof the leg actuators22is located with respect to the electric motor22amay be opposite to each other.

As a still further example, the position of the upper end11fof the yawing actuator11may be higher than the upper end22eof the left and right leg actuators22. Further, the position of the lower end11eof the yawing actuator11may be higher than the lower end22fof the left and right leg actuators22.

As depicted inFIGS.4A and4B, the pitching actuator12is arranged above the yawing actuator11. The pitching actuator12is supported by the yawing actuator11. More particularly, a frame62that holds the pitching actuator12thereon is attached to the rotation outputting section11cof the yawing actuator11. The pitching actuator12and elements supported on the pitching actuator12, more particularly, the rolling actuator13and an upper portion of the trunk10, are rotated (yawing) around the rotation center line A11extending along the upward and downward direction by driving of the yawing actuator11.

As depicted inFIGS.4B and5B, the pitching actuator12is located above the upper end22eof the left and right leg actuators22. Also the location of the frame62(refer toFIG.4A) that holds the pitching actuator12thereon is higher than the upper end22eof the left and right leg actuators22. By this arrangement, the frame62and the pitching actuator12can be prevented from interfering with the leg actuators22irrespective of the size of the pitching actuator12in the leftward and rightward direction. As a result, the movable range of the yawing actuator11can be secured sufficiently. As depicted inFIG.4A, a right side portion and a left side portion of the frame62are located above the right side leg actuator22, more particularly, above the electric motor22a, and above the left side leg actuator22, more particularly, above the electric motor22a, respectively, and they overlap partly with the leg actuators22as viewed in top plan.

As depicted inFIG.4B, the pitching actuator12includes an electric motor12a, a speed reduction mechanism, and a rotation outputting section12cthat receives rotation of the electric motor12athrough the speed reduction mechanism. The rotation outputting section12cis located on the rotation center line A12of the electric motor12a. The speed reduction mechanism is arranged between the rotation outputting section12cand the electric motor12a. For such a speed reduction mechanism as just described, for example, a planetary gear can be used.

As depicted inFIG.5B, the rolling actuator13is arranged in the rear of the pitching actuator12. Further, the rolling actuator13is located above the electric motor11aof the yawing actuator11. The rolling actuator13and an upper portion of the trunk10are supported by the pitching actuator12such that they move (pitching) around the rotation center line A12of the pitching actuator12extending along the leftward and rightward direction by driving the pitching actuator12. In other words, the trunk10can be tilted to the front by driving of the pitching actuator12.

As depicted inFIGS.2B and3B, a connection frame63is attached to the rotation outputting section12cof the pitching actuator12. The rolling actuator13is attached to the connection frame63. The connection frame63has a supporting portion63aarranged, for example, along the rotation center line A12of the pitching actuator12, a first arm portion63bextending from one end portion of the supporting portion63atoward the rotation outputting section12cand attached to the rotation outputting section12cthrough a first attached portion63ghereinafter described, and a second arm portion63cextending from an opposite side end portion of the supporting portion63atoward the rotation center line A12. The second arm portion63cis supported by a bearing14(refer toFIG.2B) on the opposite side to the rotation outputting section12con the rotation center line A12.

As depicted inFIGS.2B and3B, the rolling actuator13includes the electric motor13a, a speed reduction mechanism, and the rotation outputting section13cthat receives rotation of the electric motor13athrough the speed reduction mechanism. The structure of the rolling actuator13may be same as that of the yawing actuator11. As depicted inFIG.2B, the rotation outputting section13cof the rolling actuator13is attached to the supporting portion63aof the connection frame63. On the other hand, an upper portion of the trunk10is supported by the remaining portion of the rolling actuator13. In particular, frames64A and64B that support a main board15, the shoulder actuators32, and the head actuator42thereon are attached to a case13d(refer toFIG.3B) that accommodates the speed reduction mechanism of the rolling actuator13. The frame64A has a pair of attachment wall portions64b(refer toFIG.3B) extending downwardly. The case13dis arranged between the attachment wall portions64band attached to the attachment wall portions64b.

If the rolling actuator13is driven, then the case13din which the electric motor13aand the speed reduction mechanism are accommodated is rotated around the rotation center line A13(refer toFIG.2B) of the rotation outputting section13c. As a result, the upper portion of the trunk10is tilted leftwardly or rightwardly (rolling).

As depicted inFIG.5B, the electric motor13ais spaced upwardly from the rotation center line A13of the rotation outputting section13c. The upper portion of the trunk10, namely, the portion that holds the shoulder actuators32and the head actuator42, is located above the electric motor13a. By this location, the distance from the rotation center line A13of the rolling actuator13to the upper portion of the trunk10can be secured sufficiently. As a result, the movement of the upper portion of the trunk10, namely, tilting in the leftward or rightward direction, can be made greater. The case13dis located below the electric motor13a. The upper portion of the trunk10is fixed to the case13dthrough the attachment wall portions64b. To the case13d, the upper portion of the trunk10is fixed through the attachment wall portions64b. It is to be noted that, different from the example of the robot1, the upper portion of the trunk10may be attached to the electric motor13ain place of the case13d.

(Layout of Three Actuators)

As described hereinabove, the pitching actuator12is disposed above the yawing actuator11, and the rolling actuator13is arranged in the rear of the pitching actuator12. The upper portion of the trunk10, namely, the portion at which the shoulder actuators32and the head actuator42are arranged, is arranged above the rolling actuator13and is supported by the rolling actuator13. According to this arrangement of the three actuators11,12, and13, when the pitching actuator12is driven, namely, when the trunk10is tilted to the front, the pitching actuator12or the rolling actuator13does not interfere with any other part. As a result, the range of forward tilting of the trunk10can be secured sufficiently. Further, since a space S1(refer toFIG.4A) is secured on the lower side of a right portion and the lower side of a left portion of the trunk10, when the rolling actuator13is driven, namely, when the trunk10is tilted leftwardly or rightwardly, the upper portion of the trunk10does not interfere with any other part. As a result, also the range of tilting of the trunk10to the right and the left can be secured sufficiently.

As depicted inFIGS.4B and5B, the rotation center line A11of the yawing actuator11and the rotation center line A12of the pitching actuator12may define one plane. In other words, the rotation center line A11and the rotation center line A12may intersect with each other as viewed in both the side elevation and the front elevation of the robot1. According to this arrangement of the actuators11and12, calculation of the posture of the trunk10can be simplified. Further, according to this arrangement of the actuators11and12, the moment of inertia of the pitching actuator12around the rotation center line A11of the yawing actuator11decreases. As a result, the torque demanded for the yawing actuator11can be reduced.

Further, as depicted inFIGS.4B and5B, the rotation center line A12of the pitching actuator12and the rotation center line A13of the rolling actuator13may define one plane. In other words, the rotation center line A12of the pitching actuator12and the rotation center line A13of the rolling actuator13may intersect with each other as viewed in both the side elevation and the front elevation. According to this arrangement of the actuators12and13, calculation of the posture of the trunk10can be simplified.

For the three actuators11,12, and13, two kinds of actuators are used. In particular, a parallel actuator is used as the yawing actuator11and the rolling actuator13, and a serial actuator is used as the pitching actuator12. The parallel actuator is an actuator in which rotation center lines of a rotation outputting section and an electric motor that are connected to each other through a speed reduction mechanism are spaced from each other in a radial direction of the electric motor. The serial actuator is an actuator in which rotation center lines of a rotation outputting section and an electric motor connected to each other through a speed reduction mechanism are same as each other.

Since, in the parallel actuator, the rotation center line of the rotation outputting section is spaced in a radial director from the center rotation axis of the electric motor, the size of the parallel actuator in a direction along the rotation center line is smaller than that in the serial actuator. In contrast, the size of the serial actuator in a direction orthogonal to the rotation center line is smaller than that of the parallel actuator. In the robot1, a serial actuator is used as the pitching actuator12, and a parallel actuator is used as the rolling actuator13. By this, the overall size of the two actuators12and13in the forward and rearward direction can be reduced. As a result, a moment of inertia of the two actuators12and13generated around the rotation center line A11of the yawing actuator11can be reduced. Further, in the robot1, a parallel actuator is used as the yawing actuator11. By this, the location of the rotation outputting section11cof the yawing actuator11can be lowered and the position of the center of gravity of the robot1can be lowered.

It is to be noted that the electric motor11aand the rotation outputting section11cof the yawing actuator11correspond to the “supported portion” and the “movable portion” in the claims, respectively. Further, the electric motor12aand the rotation outputting section12cof the pitching actuator12correspond to the “supported portion” and the “movable portion,” respectively. Further, in regard to the rolling actuator13, since the rotation outputting section13cof it is supported by the pitching actuator12through the connection frame63, the electric motor13aand the rotation outputting section13cof the rolling actuator13correspond to the “movable portion” and the “supported portion” in the claims, respectively.

(Upper Portion of Trunk)

As depicted hereinabove, the upper portion of the trunk10is supported by the rolling actuator13. As depicted inFIG.2A, the left and right shoulder actuators32, the head actuator42, and the main board15are arranged at the upper portion of the trunk10. In the example of the robot1, the main board15includes two circuit boards15aand15bplaced one on the other in the upward and downward direction as depicted inFIG.2B. By this configuration, a narrow space can be utilized effectively. Different from the example of the robot1, the main board15may include one circuit board. As the shoulder actuators32and the head actuator42, for example, a parallel actuator is used.

As depicted inFIG.5B, the shoulder actuators32are arranged forwardly with respect to the rolling actuator13. According to this arrangement, the degree of freedom of the location of the shoulder actuators32in the upward and downward direction can be increased. In the robot1, the lower end32eof the shoulder actuators32is positioned lower than the upper end13eof the rolling actuator13, in the example of the robot1, lower than the upper face of the electric motor13a. According to this arrangement of the shoulder actuators32, the position of the center of gravity of the robot1can be lowered, and therefore, the stability of movement of the robot1can be improved. In the example of the robot1, the shoulder actuators32are arranged such that a horizontal plane P1that passes the upper end13eof the rolling actuator13intersects with the rotation outputting section32cof the shoulder actuators32.

As depicted inFIG.4B, the head actuator42is located between the left and right shoulder actuators32and is located in front of the rolling actuator13similarly to the shoulder actuators32. According to this arrangement, the degree of freedom of the location of the head actuator42in the upward and downward direction can be increased. In the robot1, the lower end42eof the head actuator42may be positioned lower than the upper end13eof the rolling actuator13, in the example of the robot1, lower than the upper face of the electric motor13a(refer toFIG.5). According to this arrangement of the head actuator42, since the position of the center of gravity of the robot1can be lowered, the stability of movement of the robot1can be improved.

As viewed in side elevation of the robot1, the shoulder actuators32and the head actuator42are located above the pitching actuator12. As depicted inFIG.4A, a space S1that allows rolling of the trunk10therein is secured on the lower side of the shoulder actuators32and the head actuator42.

A rotation center line A32of a rotation outputting section32cof the shoulder actuators32extends in the leftward and rightward direction, and the shoulder actuators32move the arm portions30R and30L forwardly and rearwardly. A rotation center line A42(refer toFIG.2A) of a rotation outputting section42cof the head actuator42extends in the upward and downward direction, and the head actuator42rotates the orientation of the head leftwardly and rightwardly.

The movement of the shoulder actuators32and the head actuator42is not limited to that of the robot1. For example, the rotation center line A32of the shoulder actuators32arranged at the upper portion of the trunk10may extend in the forward and rearward direction or may extend in the upward and downward direction. Similarly, the rotation center line A42of the head actuator42arranged at the upper portion of the trunk10may extend in the forward and rearward direction or may extend in the leftward and rightward direction.

Also the layout of the shoulder actuators32and the head actuator42is not limited to that of the robot1. For example, only the shoulder actuators32or the head actuator42may be located in front of the rolling actuator13, and the position of the lower end of it may be lower than the upper end13eof the rolling actuator13. In a further example, the location of both the shoulder actuators32and the head actuator42may be higher than the upper end13eof the rolling actuator13.

As depicted inFIG.5A, the main board15is located in the rear of the shoulder actuators32and the head actuator42and is located above the rolling actuator13. The main board15is arranged horizontally. The shoulder actuators32and the head actuator42are located lower than the main board15. In particular, as depicted inFIG.5B, the lower end32eof the shoulder actuators32and the lower end42e(refer toFIG.4B) of the head actuator42are located lower than the main board15, in the example of the robot1, lower than the lower side circuit board15b. Especially, in the shoulder actuators32, also the rotation center line A32thereof is located lower than the main board15, in the example of the robot1, lower than the lower side circuit board15b.

As depicted inFIGS.2B and3B, the shoulder actuators32, the head actuator42, and the main board15are attached to the frames64A and64B. In particular, the main board15is attached to the frame64A, and the shoulder actuators32and the head actuator42are held by the frame64B. The two frames64A and64B are combined in the forward and rearward direction. In particular, the frame64A is positioned in the rear of the frame64B and is secured to the frame64B by a fixing element such as a screw. The rolling actuator13is fixed to the frame64A through the attachment wall portions64b. It is to be noted that the structure of the frames64A and64B is not limited to that of the robot1. They may be an integrally formed member. In other words, the frames64A and64B may not be fixed to each other by a fixing element such as a screw but may be formed as a continuous member by a single time casting step or metal working.

(Board and Electric Cable)

The main board15has a circuit for connecting to an external apparatus such as, for example, a computer for controlling the robot1or a power supply device. The actuators11,12,13, and22have servo boards S11, S12, S13, and S22provided thereon, respectively. In the following description, where the servo boards are not distinguished from each other, each servo board is referred to as servo board S. Each servo board S supplies electric power to an actuator such that the actuator implements a movement according to an instruction received from the main board15. The servo board S is attached to a frame on which an actuator controlled by the servo board S is supported. For example, the servo board S1l(refer toFIG.3A) that controls the yawing actuator11and the servo board S22(refer toFIG.3A) that controls the leg actuators22are attached to the frame61on which the actuators11and22are supported. Meanwhile, the servo board S12(refer toFIG.2B) that controls the pitching actuator12is attached to the frame62on which the pitching actuator12is supported. Further, the servo board S13(refer toFIG.3B) that controls the rolling actuator13and the servo board S32(refer toFIG.2B) that controls the shoulder actuators32are attached to the frame64B on which the actuators13and32are mounted.

In the robot1, a plurality of servo boards S are connected in series. For example, the servo boards S of the actuators11,12, and13for moving the trunk10and the servo boards S of the three actuators11,12, and13(refer toFIG.1) provided on the head are connected in series. By the connection, the number of wirings can be reduced. The number of servo boards S to be connected in series may be more than three. For example, also the servo boards for the actuators42,43, and44for moving the head may be connected in series to the servo boards S11, S12, and S13.

The robot1has a plurality of electric cables P7(refer toFIG.3A) connected to a plurality of servo boards S and extending from the main board15. The plurality of electric cables P7include cables for supplying electric power from the main board15to the servo boards S, cables for sending control signals from the main board15to the servo boards S and so forth.

As depicted inFIG.3A, the electric cables P7are arranged along an outer face, namely, along a lower face, of the rolling actuator13and then extend forwardly toward the pitching actuator12as depicted inFIG.2A. To the frame64A on which the rolling actuator13is held, a clamp member64a(refer toFIG.3A) for fixing the electric cables P7is attached. Also to the connection frame63that connects the pitching actuator12and the rolling actuator13to each other, clamp members63dand63e(refer toFIG.5A) are attached. After passing through the three clamp members64a,63d, and63e, the electric cables P7pass a side portion of the pitching actuator12and further extend downwardly. As depicted inFIG.5A, the electric cables P7extend downwardly intersecting with the rotation center line A12of the pitching actuator12, in other words, with the rotation center line of the connection frame63. The frame62has a cable guide62a(refer toFIG.2A) formed on the lower side of the pitching actuator12. The electric cables P7passing the rotation center line A12of the pitching actuator12extend toward the cable guide62a. The location of the electric cables P7is defined by the cable guide62aand the clamp member63e. By laying out the electric cables P7in this manner, the load that is to act upon the electric cables P7when the pitching actuator12is driven can be reduced.

The connection frame63attached to the pitching actuator12is described with reference toFIGS.7A to9B. It is to be noted that the structure of the connection frame63described below may be applied to an actuator different from the pitching actuator12. Referring toFIG.1, the structure of the connection frame63described below may be applied, for example, to the actuator43arranged on the head portion, the actuator23located at an upper portion of the leg portions20R and20L, and the actuators33and35of the arm portions30R and30L. In particular, in a case where a connected part, for example, a second actuator located next, is located in a direction orthogonal to the rotation center line of a first actuator, the structure of the connection frame63may be applied to a connection frame that is attached to a rotation outputting section of the first actuator. In the following description regarding the connection frame63, the pitching actuator12is referred to merely as actuator.

As depicted inFIGS.7A and7B, the connection frame63has a substantially U shape and is arranged such that it sandwiches the actuator12on the rotation center line A12of the actuator12. The connection frame63has a first attached portion63g(refer toFIGS.2B and7C) attached to the rotation outputting section12c(refer toFIG.4A) of the actuator12. The first attached portion63gfaces the rotation outputting section12cin a direction along the rotation center line A12. The first attached portion63gis attached to the rotation outputting section12c, for example, by a plurality of screws63h, for example, three screws63h.

As depicted inFIG.7B, the bearing14is arranged on the opposite side to the rotation outputting section12cacross the actuator12. The connection frame63has, on the opposite side thereof to the first attached portion63g, a second attached portion63iattached to the bearing14. The second attached portion63iis an annular portion formed at a base portion of the second arm portion63c. The bearing14is fitted on the inner side of the second attached portion63i. The remaining portion of the connection frame63, namely, the portion other than the first attached portion63g, further has the supporting portion63aand the first arm portion63b. The first attached portion63gand the second attached portion63iare connected to each other through the first arm portion63b, the supporting portion63a, and the second arm portion63c. The rolling actuator13is attached to the supporting portion63a(refer toFIG.2B). By driving of the pitching actuator12, the connection frame63rotates relative to the actuator12and the frame62around the rotation center line A12.

In the example of the robot1, the second arm portion63cand the supporting portion63aare formed integrally. In particular, the second arm portion63cand the supporting portion63aare not fixed to each other by a fixing element such as a screw but are formed as a continuous member by a casting step or a metal working. On the other hand, the first arm portion63bis a member formed separately from the first attached portion63gand the supporting portion63a. The first arm portion63bis attached to the first attached portion63gand the supporting portion63aby fixing elements such as, for example, screws63nand63m.

The robot1includes a rotation sensor16for detecting a movement and a location of the actuator12. As depicted inFIGS.7A and7C, the rotation sensor16has a sensor rotation portion16aattached to the connection frame63and a sensor fixed portion16bthat faces the sensor rotation portion16ain a direction along the rotation center line A12. The rotation sensor16is a magnetic angle sensor that detects rotation using, for example, a change of magnetic fluxes. The sensor rotation portion16ais, for example, a magnet. The sensor fixed portion16bis a sensor board on which, for example, a Hall integrated circuit (IC) is mounted and outputs a signal according to a magnetic flux change arising from rotation of the sensor rotation portion16a. Depending upon the place where the pitching actuator12and the connection frame63are used, the sensor rotation portion16amay be a sensor board and the sensor fixed portion16bmay be a magnet.

(Movable Range of First Attached Portion)

The sensor rotation portion16ais attached not to the first arm portion63bbut to the first attached portion63g. The sensor rotation portion16ais located on the rotation center line A12of the actuator12. As depicted inFIG.9A, the first attached portion63gis attached to the rotation outputting section12c. The remaining portions of the connection frame63, namely, the first arm portion63b, the supporting portion63a, and the second arm portion63c, can be removed from the first attached portion63g. In this state, the first attached portion63gand the rotation outputting section12care rotatable around the rotation center line A12over an angle greater than 360 degrees (one rotation). In short, when the first attached portion63gand the rotation outputting section12care rotated over an angle greater than 360 degrees, they do not interfere with any of the other parts, members, and portions. In the example of the robot1, when the first attached portion63gand the rotation outputting section12care rotated, they do not interfere with the frame62on which the actuator12is supported.

As depicted inFIG.9A, in the state in which the rotation sensor16is attached to the first attached portion63gof the connection frame63, calibration of the rotation sensor16can be performed. On the other hand, in a case in which the remaining portions of the connection frame63are removed from the first attached portion63g, the first attached portion63gand the rotation outputting section12care rotatable over an angle greater than 360 degrees, in other words, there is no limitation to the rotational range of the first attached portion63gand the rotation outputting section12c. Therefore, by performing calibration in this state, the calibration can be performed accurately.

(Frame and First Attached Portion)

The frame62on which the actuator12is supported has a main body62cattached to the actuator12and a sensor supporting section62das depicted inFIG.7A. Further, the frame62may have a bearing supporting section62g(refer toFIG.7B) that supports the bearing14thereon. As depicted inFIG.7B, the bearing supporting section62ghas a supporting portion62kthat supports thereon an outer edge of the second attached portion63iof the connection frame63attached to the bearing14.

The sensor fixed portion16b, particularly the sensor board, is attached to the sensor supporting section62d. The sensor supporting section62dis attached to the main body62cby a fixing element such as a screw. According to this structure of the frame62, it is possible to perform, in a state in which the sensor supporting section62dis removed from the main body62c, a work for attaching the first attached portion63gto the rotation outputting section12cby the screws63h, and the attachment work of the first attached portion63gis facilitated.

As depicted inFIG.7A, the sensor supporting section62dhas a connection portion62eextending in a direction along the rotation center line A12from the main body62cand a side portion62fextending from the connection portion62etoward the rotation center line A12. The sensor fixed portion16bis attached to the side portion62f.

As depicted inFIG.8, the first attached portion63ghas a remotest portion63jlocated most apart from the rotation center line A12of the rotation outputting section12cof the actuator12. The distance from the rotation center line A12to the remotest portion63jis smaller than the distance from the rotation center line A12to the frame62, more particularly, than the distance from the rotation center line A12to the connection portion62eof the frame62, namely, than the length of a perpendicular line from the rotation center line A12to the connection portion62e. Since the first attached portion63gis formed with such a size as just described, the first attached portion63gand the rotation outputting section12care rotatable over an angle greater than 360 degrees. It is to be noted that the rotation outputting section12cis located on the inner side with respect to the outer edge of the first attached portion63g.

(Attachment Structure of First Attached Portion and First Arm Portion)

As depicted inFIG.7D, when the actuator12is viewed in a direction along the rotation center line A12, the first attached portion63gand the first arm portion63bhave a region R1in which they are not covered with the side portion62fof the frame62, namely, a region formed outside an outer edge62hof the side portion62fof the frame62. The first arm portion63band the first attached portion63gare fixed to each other by a plurality of fixing elements inserted in attachment holes formed in the region R1, particularly by screws63nas depicted inFIG.7D. According to this structure, it is possible to attach the first arm portion63bto the first attached portion63gwithout removing the sensor supporting section62d, to which the sensor fixed portion16b, namely, the sensor board, of the rotation sensor16for which calibration is completed, is fixed, from the main body62cof the frame62.

The region R1includes an overall region that is exposed on the outer side of the outer edge62hof the side portion62fof the frame62by rotating the first arm portion63band the first attached portion63garound the rotation center line A12. Accordingly, the region R1includes also a portion covered with the side portion62fwhen the rotational position of the first arm portion63bis fixed at a certain angle, and also in the covered portion, fixing elements, particularly the screws63n, are inserted. According to this structure, the number of attachment locations between the first arm portion63band the first attached portion63gcan be increased, and the durability of the connection frame63can be enhanced.

(Remaining Portion of Connection Frame)

The remaining portion of the connection frame63can be divided. In particular, portions that have the first arm portion63band the second attached portion63iare connected to each other by fixing elements such as screws63nand can be separated from each other. Therefore, the second attached portion63ican be fitted with the bearing14in a direction along the rotation center line A12. In addition, the fixing elements, namely, the screws63n, can be inserted into the first arm portion63band the first attached portion63gin a direction along the rotation center line A12. Therefore, the number of fixing elements such as the screws63ncan be increased easily in comparison with that in an alternative structure in which, for example, the first attached portion63gand the first arm portion63bare fixed to each other in a radial direction. Therefore, the durability and the strength of the connection frame63can be enhanced.

In the example of the robot1, the second attached portion63iis part of the second arm portion63c, and the second arm portion63cand the supporting portion63aconfigure a single member formed integrally, as described hereinabove. The supporting portion63aand the first arm portion63bare fixed to each other by a plurality of screws63m(refer toFIG.7A). In a manufacturing process of the robot1, after calibration is completed, the first arm portion63bis attached to the first attached portion63gwith the screws63nas depicted inFIG.9B. Further, the second attached portion63iis fitted into the bearing14, and then the first arm portion63band the supporting portion63aare fixed to each other by the screws63m.

Different from the example of the robot1, the first arm portion63band the supporting portion63amay configure one member formed integrally, and the supporting portion63aand the second arm portion63cmay be fixed to each other by screws. In a further example, the first arm portion63b, the supporting portion63a, and the second arm portion63cmay form one member formed integrally by casting or metal working.

(1) As described above, the robot1includes the yawing actuator11that allows yawing of the trunk10, the pitching actuator12that is arranged above the yawing actuator11and is supported by the yawing actuator11, the pitching actuator12allowing pitching of the trunk10, and the rolling actuator13that is arranged in the rear of the pitching actuator12and is supported by the pitching actuator12, the rolling actuator13allowing rolling of the trunk10. According to the robot1, the tilting range to the front of the trunk10can be secured, and the tilting range in the leftward and rightward direction of the trunk10can be secured.

(2) Further, the robot1includes the leg actuators22that move the leg portions20and the yawing actuator11that is located between the left and right leg actuators22as viewed in front elevation of the robot1and allows yawing of the trunk10. Further, the robot1includes the actuators12and13that are arranged above the yawing actuator11and allow pitching of the trunk10and rolling of the trunk10, respectively. According to this robot, since the position of the actuators11,12, and13for moving the trunk10can be lowered as a whole, the position of the center of gravity of the robot1is lowered and the stability in movement of the robot1can be improved. It is to be noted that, in the structure just described, only one of the pitching actuator12and the rolling actuator13may be provided as an actuator to be arranged above the yawing actuator11, namely, as the actuator that moves the trunk10. Further, in this structure, only one of the pitching actuator12and the rolling actuator13may be an actuator to be arranged above the yawing actuator11, namely, as the actuator for moving the trunk10.

(3) The pitching actuator12and the rolling actuator13are arranged side by side in the forward and rearward direction of the robot1. While the pitching actuator12is a serial actuator, the rolling actuator13is a parallel actuator. In particular, in the pitching actuator12, the rotation center line A12of the rotation outputting section12cis same as the rotation center line of the electric motor12a. Meanwhile, in the rolling actuator13, the rotation center line A13of the rotation outputting section13cis spaced in a radial direction of the electric motor13afrom the rotation center line B13of the electric motor13a. By this structure, the size of the trunk10of the robot1in the forward and rearward direction can be reduced.

(4) The connection frame63has the first attached portion63gattached to the rotation outputting section12cof the pitching actuator12, and the remaining portion connected to the first attached portion63g, namely, the first arm portion63b, the supporting portion63a, and the second arm portion63c. The rotation sensor16has the sensor rotation portion16aattached to the first attached portion63g, and the sensor fixed portion16bfacing the sensor rotation portion16a. The rotation sensor16outputs a signal according to rotation of the sensor rotation portion16awith respect to the sensor fixed portion16b. In a state in which the first attached portion63gis attached to the rotation outputting section12cand the remaining portion of the connection frame is removed from the first attached portion63g, the first attached portion63gand the rotation outputting section12care rotatable over an angle greater than 360 degrees.

According to the structure of (4), calibration of the rotation sensor16can be performed in a state in which the sensor rotation portion16aof the rotation sensor16is attached to the first attached portion63gof the connection frame63. Further, in a state in which the remaining portion of the connection frame63is removed from the first attached portion63g, since the first attached portion63gcan rotate over an angle greater than 360 degrees, in other words, since there is no limit to the range of rotation of the first attached portion63g, calibration can be performed accurately by performing the calibration in this state.

It is to be noted that the structure of the connection frame63described in (4) above may be applied to an actuator different from the pitching actuator12. Referring toFIG.1, the structure of the connection frame63described in (4) above may be applied, for example, to the actuator43arranged on the head portion, the actuator23located at an upper portion of the leg portions20R and20L, and the actuators33and35of the arm portions30R and30L.

The pitching actuator12is a serial actuator in which the rotation center line of the rotation outputting section and the rotation center line of the electric motor are same as each other. However, the connection frame63described in (4) above may be applied to a parallel actuator in which the rotation center line of the rotation outputting section is spaced away from the rotation center line of the electric motor. In this case, the first attached portion63gmay be attached to the rotation outputting section of the actuator, and the second attached portion63iof the connection frame63may be attached to the bearing located on the opposite side to the actuator, which is the speed reduction mechanism, across the rotation outputting section.

In the example of the robot1, the rolling actuator13is attached as a connected part to the connection frame63. However, the connected part may not be the actuator but may be a frame configuring the arm portions30R and30L of the robot1or a frame configuring the leg portions20R and20L.

In a still further example, depending upon the location of the actuator to which the connection frame63is attached, the location of the connection frame63may be fixed, and the actuator and the frame that supports the actuator may be moved relative to the connection frame63by driving of the actuator. In this case, a board on which a Hall IC is mounted as the sensor rotation portion16amay be attached to the connection frame63, and a magnet may be attached as the sensor fixed portion16bon a frame that supports the actuator.