Robot hand apparatus

A robot hand apparatus (1) includes a base (2); a motor (M); a first-link (10) supported by the base (2) while allowing the rotation around a first axis (S1), which is in parallel to an actuation axis (G) of the motor (M) and is positioned apart from the actuation axis (G), the first-link (10) has a first guide path (11b) movably supporting a control axis (42); a second link (20) which connects with the actuation axis (G) and supports the control axis (42), and moves the control axis (42) within the first guide path (11b) in accordance with the rotation of the actuation axis (G); and a finger link (F1) supported by the first link (10) while allowing the rotation around a second axis; and the finger link (F1) directly or indirectly links with the control axis (42) and is rotated by the actuation of the control axis (42).

FIELD OF THE INVENTION

The present invention relates to a robot hand apparatus which can actuate a finger around two cross-axes crossing each other.

BACKGROUND OF THE INVENTION

Conventionally, a research and development of a robot hand apparatus mimicking a hand of a human has been made to make the robot to do various kinds of tasks.

For representing the function of a thumb among five fingers of a human, for example, two crossing axes are required, if it is assumed a palm is facing upside (see Japanese unexamined patent publication JP No. 2003-117873). Here, one of two crossing axes is an axis for rotating a thumb in a height direction, and the other of two crossing axes is an axis for rotating the thumb in a left-and-right direction.

In the conventional robot hand apparatus, however, a total of two sets, each consisting of a motor, a reduction unit, and a motor driver, are required for each axis, for actuating the finger around two crossing axes. In this case, since the number of the parts and the weight of the robot hand apparatus are increased, this becomes the defect for a humanoid-type robot restricted in a volume and an output.

Therefore, the robot hand apparatus which can actuate a finger around two crossing axes with simple mechanism has been required.

SUMMARY OF THE INVENTION

The present invention relates to a robot hand apparatus, which has a base, a motor, a first-link, a second link, and a finger link. In this robot hand apparatus, the motor is fixed to the base, and the first-link is supported by the base while allowing the rotation around a first axis, and has a first guide path in which a control axis is movable. Here, the first axis is an axis in parallel to an actuation axis of the motor and is positioned apart from the actuation axis.

The second link connects with the actuation axis of the motor and supports the control axis. The second link moves the control axis within the first guide path in accordance with the rotation of the actuation axis of the motor, and the finger link is supported by the first link while allowing the rotation around a second axis crossing the first axis. The finger link directly or indirectly links with the control axis so that the finger link is rotated around the second axis in accordance with the actuation of the control axis.

According to this robot hand apparatus, since finger link can be rotated around two crossing axes using a single motor, the motor, the reduction unit, and the motor driver are not required for each axis.

In this robot hand apparatus, for example, it is preferable that the base has a second guide path within the moveable range of the first guide path, and the second link includes a rotator, which is fixed to the actuation axis, and a connection link, which is rotatably supported by the rotator and supports the control axis.

According to this construction, the first link and the finger link can be actuated separately. For example, the finger link can be actuated after the actuation of the first link.

Furthermore, it is preferable that the second guide path is formed by connecting a first guide hole and a second guide hole. In this case it is preferable that the first guide hole is formed by elongating in a circumference direction around the first axis, and that the first guide hole guides the control axis in a circumference direction around the first axis. It is still more preferable that the second guide hole is formed by elongating in a radial direction with respect to the first axis, and that the second guide hole guides the first axis in a radial direction.

According to this construction, the first link can be actuated around first axis by the first guide hole, and the finger link can be actuated around the second axis by the second guide hole.

Still furthermore, it is preferable that the control axis is adapted to slide within the first guide hole and the second guide hole.

According to this construction, the finger link can be actuated smoothly and constantly on a constant locus.

According to the present invention, since the finger link can be actuated around two axes using a simple mechanism, the reduction of the number of the parts can be achieved. Thus, since the reduction in a volume and weight of the mechanism of the robot hand apparatus can be enabled, the robot hand apparatus of the present invention is suitable for the use in a humanoid-type robot.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The robot hand apparatus1of the present embodiment relates to the construction about the finger which corresponds to a thumb of a human. In this embodiment, the robot hand apparatus1is provided to each arm R3. But, in the following explanation, the explanation is carried out about the robot hand apparatus1installed on the right hand, and the explanation about that of installed on the left hand will be omitted. This is because the left hand is symmetrical with respect to the right hand.

As shown inFIG. 1, the robot hand apparatus1of the present embodiment is provided at an end of the arm R3of a bipedal waling robot R. This robot R has two legs R1, a body R2, two arms R3, and a head R4, like a human. In this figure, the leg R1and arm R3disposed on a right side of the robot R is not shown. Additionally, the head R4has cameras, microphone, and speaker, which are omitted in this figure.

As shown inFIG. 2, the robot hand apparatus1has a five fingers Fa, Fb, Fc, Fd, and Fe, like a human. A finger link F1is installed on the finger Fa, which corresponds to a thumb of a human, and is allowed to change the posture between posture A, posture C, and posture B. In thisFIG. 2, the posture A and posture B are respectively indicated using a dot dash line.

To be more precise, as shown inFIG. 3andFIG. 5A, the posture A is the condition where the finger link F1is flexed inside and is in the vicinity of the palm section. As shown inFIG. 3andFIG. 5B, the posture B is the condition where the finger link F1is flexed inside and is separated from the palm section. As shown inFIG. 3, the posture C is the condition where the finger link F1is stretched and is in the outside than the posture B.

Similar to a hand of a human, additionally, each of the remaining fingers Fb-Fe is provided with a first joint and a second joint and is actuated by other motor (not shown) and a link mechanism so as to change the posture between a stretched posture and a hunched posture. Here, the case where each of the fingers Fb-Fe is in a stretched posture is shown inFIG. 2.

As shown inFIG. 4, the robot hand apparatus1has the finger link F1, a motor M, a first link10, and a second link20.

The finger link F1of the present embodiment, as shown inFIG. 3andFIG. 7, consists of a finger base50, a finger tip51, a cover52, and a cover53. The finger tip51rotatably connects with the tip of the finger base50. The cover52and the cover53cover the periphery of the finger base50and the finger tip51, respectively, and has a shape of a finger (seeFIG. 3).

As shown inFIG. 4, the motor M is fixed to a base2, which is a plate-like shaped member, through a reduction unit G. This base2is fixed to a base stage S provided on a wrist of the arm R3.

In the present embodiment, additionally, a motor base5, to which the motor M is fixed, is fixed to the base stage S, and the reduction unit G is fixed to the base2and motor base5through a screw. The motor M is fixed to the region in a direction X1side of the base2, and an actuation shaft g, which connects with an output shaft (not shown) of the motor M through the reduction unit G, elongates in a direction X2side.

Furthermore, a rotation hole2aand a second guide path2b, each penetrates in a direction parallel to the line X1-X2, are provided on the base2. The position where the second guide path2bis provided is in the vicinity of the rotation hole2a. In this embodiment, the line X1-X2is in parallel to the output shaft of the motor M.

The second guide path2bcomprises a second guide hole2b2, which is a curved hole elongating in a circumference direction around the rotation hole2a, and a first guide hole2b1, which is a straight long hole elongating in a radial direction. The second guide path2bis formed by joining the first guide hole2b1and the second guide hole2b2.

The first link10is obtained by combining into an integral body a pair of legs11and12and a pair of guide plates13and14.

Each of legs11and12is disposed in parallel to the base2and each of legs11and12is an elongated plate. The base end of the leg11and12is provided with a hole11aand12aand a guide long hole (a first guide path)11band12brespectively. A predetermined interval is provided between the hole11a(12a) and the guide long hole11b(12b).

Additionally, the leg11and12are disposed in parallel in a direction along the line X1-X2. The guide plate13and14, each is a trapezoidal shaped plate member, is disposed in parallel with a predetermined interval in a direction orthogonal to the leg11and12(or the base2).

A connection hole13aand14ais formed at a corner in an direction X2side of the guide plate13and14. A clearance15with a predetermined width is formed between the side-surface12cof leg12and the edge13band14bof the guide plate13and14.

The second link20consists of a rotator21and a connection link22. The rotator21is a disk-like shaped member and is disposed in parallel to the base2. A driven hole21awhich serves as a rotation center, and a connection hole21bare formed on the rotator21. Here, the position where the connection hole21bis formed is the eccentric position with respect to the driven hole21a. Additionally, a protrusion21chaving a sector shape is provided on the rotator21and is formed into an integral shape with the rotator21. The position where the protrusion21cis provided is the position opposite across the driven hole21awith regard to the connection hole21b.

The connection link22has a long link plate22a, which has a through hole22a1at one end thereof and has a connection hole22a2at the other end thereof, and a short link plate22b, which has a through hole22b1being coaxial with respect to the through hole22a1.

The long link plate22aand the short link plate22bare disposed in parallel in a direction along the line X1-X2by the connection plate22cso that a predetermined interval is secured therebetween.

A elevating member30is provided on the connection link22. The elevating member30has a side plate30a, which faces a direction along the line X1-X2, a pair of side plates30band30borthogonal to the side plate30a, and a bottom plate30c(seeFIG. 7). A rectangular shaped space Q is formed inside of the elevating member30. The side plate30ais provided with a connection hole30a1, and the side plate30band30bis provided with a pin connection hole30b1and30b1. Here, the distance between side plates30bof the elevating member30is established so that the elevating member30can slide between the guide plate13and the guide plate14.

An arm member31is provided to the elevating member30. The width of the arm member31is established so that the arm member31can be inserted between the side plates30band30b, and one end of the arm member31is curved to a direction X2side. The arm member31is provided with pin holes31aand31b, which are in parallel to the pin connection hole30b1, at base end and tip thereof.

The finger base50which constitutes a part of the finger link F1has a pair of connection sections50aand50a. The connection sections50aand50aare disposed with an interval therebetween so that the insertion to this interval of the arm member31is enabled.

Each connection section50ais provided with a pin connection hole50a1which is in parallel to the pin hole31b, and a connection hole50a2which is in parallel to the connection hole13aand14ais provided in the vicinity of the pin connection hole50a1. Here, the connection hole50a2disposed on one of the connection sections50ais not shown inFIG. 4.

In the present embodiment, additionally, a bearing60which can slide within the second guide path2bis provided. The bearing60is obtained by sandwiching a plurality of balls, which are aligned along a periphery direction while allowing the rotation, between an inside ring (not shown) and an outside ring (not shown). The bearing60is adapted to move the inside of the second guide path2bwhile keeping the contact between the circumference thereof with the inside circumference of the second guide path2b. In the present embodiment, dropout prevention means (not shown) is provided on a control axis42or the base2for preventing the dropout of the bearing60from the second guide path2b.

Next, the assembling of the present embodiment's robot hand apparatus1will be explained.

As shown inFIG. 4, the first link10connects with the base2through a rigid axis40. That is, after disposing the first link10so that the base2is positioned between the leg11and the leg12, the rigid axis40is inserted from a direction X1side in order of: the hole11a, the rotation hole2a, and the hole12a. Thereby, the first link10connects with the base2while allowing the rotation around the rigid axis40.

Here, the rotation center of the first link10serves as a first axis S1(seeFIG. 2andFIG. 3).

Then, the driven hole21aof the rotator21is fixed to the actuation shaft g of the motor M, and the connection hole22a2of the connection link22is connected to the connection hole21bof the rotator21through the link axis41. Thereby, the connection link22becomes rotatable with respect to the rotator21.

Next, after disposing the connection link22so that leg12is positioned between the long link plate22aand the short link plate22b, which are provided to the connection link22, the first link10and the second link20are connected each other by the control axis42.

That is, after disposing the long link plate22awithin the clearance15between the leg12and the guide plates13and14, and disposing the short link plate22bbetween the leg12and base2, which is positioned between legs11and12, the control axis42is inserted from a direction X1side in order of: guide long hole11bof the leg11, the second guide path2bof the base2, the bearing60, the through hole22b1of the short link plate22b1, the long hole12bof the leg12, the through hole22a1of the long link plate22a, and the connection hole30a1of the elevating member30. Thus, the first link10and the connection link22of the second link20are joined each other.

Thereby, the control axis42is guided by long holes11band12band the second guide path2b, and the elevating member30moves between the guide plate13and the guide plate14while rotating with respect to the connection link22.

Then, the a pin43is inserted into the pin connection hole30b1and30b1of the elevating member30and the pin hole31aof the arm member31, under the condition the base end of the arm member31is inserted into the space Q of the elevating member30. Thereby, the arm member31rotatably connects with the elevating member30.

Additionally, a pin44is inserted into the pin hole3lbof the arm member31and the pin connection hole50a1and50a1of the connection section50aand50a, under the condition the tip of the arm member31is inserted between the connection sections50aand50aof the finger link F1. Thereby, the arm member31is rotatably connects with the finger link F1.

Furthermore, a connection pin45is inserted into the connection hole50a2and50a2one of them is not shown of the connection section50aand50aand connection hole13aand14aof the guide plate13and14, under the condition the connection section50aand50aof the finger link F1is inserted between the guide plates13and14of the first link10. Thereby, the finger link F1rotatably connects with the first link10.

Next, the motion of the robot hand apparatus1of the present embodiment will be explained mainly with reference toFIG. 5andFIG. 6, and appropriately with reference to other drawings.

In the robot hand apparatus1of the present embodiment, as described above, the finger link F1changes the posture between posture A, posture C, and posture B, under the condition where the palm section is facing an upside. Here, the posture A is the condition where the finger link F1is flexed inside and is in the vicinity of the palm section. The posture B is the condition where the finger link F1was rotated, from posture A, around the first axis S1(seeFIG. 2andFIG. 3) to an upper direction separating from the palm section. The posture C is the condition where the finger link F1was rotated, from posture B, around the second axis S2to the outside.

In the present embodiment, additionally, the finger link F1slightly turns outside around the second axis S2(seeFIG. 2andFIG. 3), during the change of the posture from posture A to posture B. Here, inFIGS. 5A to 5C, the indication of the arm member31to be connected to the elevating member30, the finger base50to be connected to this arm member31, and the finger tip51is omitted.

The posture A shown inFIG. 5Ais the condition where the rotator21was fully rotated in a clockwise direction around the actuation shaft g. As shown inFIG. 6A, the control axis42is positioned within the first guide hole2b1of the second guide path2b, and is in the vicinity of a base side (a rigid axis40side) of the guide long hole11bof the leg11.

Here, though the guide long hole12bof the leg12is not shown in this figure, the control axis42is positioned in the guide long hole12bat almost the same position as the position within the guide long hole11bof the control axis42. Thereby, the first link10rotates in a clockwise direction around the rigid axis40which serves as the first axis S1as the supporting point.

As shown inFIG. 5A, the finger link F1is flexed in compliance with the flexing of the first link10. Additionally, due to the flexing of the first link10, the elevating member30sandwiched between guide plates13and14turns in a clockwise direction around the control axis42, which serves as the supporting point, together with the first link10, and thus the elevating member30is positioned at the end (rigid axis40side) of the guide pate13and14.

In the condition of posture A ofFIG. 5AandFIG. 6A, the connection link22begins to rotate in a clockwise direction with respect to the rotator21around the link axis41, when the rotator21is rotated in an anti-clockwise direction.

In this occasion, since the bearing60disposed on the control axis42moves upward along the first guide hole2b1of the second guide path2bdue to a torque of the connection link22, the posture is changed to the posture B shown inFIG. 5BandFIG. 6B.

Here, since the second guide hole2b2is formed along the circular arc equidistant from the rigid axis40, the position within the guide long hole11bof the control axis42does not change relatively.

That is, since the supporting point (rigid axis40) of the rotation of the first link10is fixed to the base2, and the direction of the guide long hole11bcrosses the direction of the first guide hole2b1, the leg11(first link10) is rotated to a direction standing the leg11(first link10).

Additionally, due to anti clockwise direction's rotation of the first link10, the finger link F1supported by the finger link F1is also rotated in an anti clockwise direction, which is a direction apart from the palm, around the first axis S1, as the supporting point.

Next, in posture B ofFIG. 5BandFIG. 6B, the bearing60provided on the control axis42slides upward due to a torque of the connection link22, when the rotator21is still rotated to an anti clockwise direction. Then, the control axis42comes in contact with the tip of the guide long hole11band thus the posture is changed to the posture B shown inFIG. 5CandFIG. 6C.

In this occasion, since the second guide hole2b2is formed along a direction separating from the rigid axis40, the position within the guide long hole11bof the control axis42changes so that the control axis42gradually separate from the rigid axis40. That is, in the posture B, since the direction of the second guide hole2b2and the direction of the guide long hole11bagree with each other, further rotation of the first link10leg11in an anti clockwise direction is forbidden. Thus, the elevating member30connected to the connection link22is lifted under the guide of the guide plate13and14.

In this occasion, as shown inFIG. 7, the arm member31disposed on the elevating member30is pushed upward, and thus the finger link F1is pushed upward through the supporting point disposed inside with respect to the connection pin45. Thus, the finger link F1is rotated to an outside around the connection pin45which serves as the supporting point. That is, the finger link F1rotates around the second axis S2.

In the present embodiment, additionally, a protruding part25is formed on the base2so that the protruding part25intersects with a rotation locus of the protrusion21cdisposed on the rotator21. The protruding part25contacts with the protrusion21cof rotator21when the posture is changed to the posture C ofFIG. 5CandFIG. 6C, and the protruding part25forbids the further rotation in an anti clockwise direction of the rotator21.

When changing the posture of the finger link F1to the posture A from the posture C, on the contrary, the elevating member30moves downward between the guide plate13and the guide plate14while supporting the control axis42by the guide long hole11band the second guide hole2b2, by rotating the rotator21in an anti clockwise direction under the posture C.

Thereby, the finger link F1is rotated to an inside direction around the connection pin45, which serves as the supporting point (seeFIG. 2), and thus the posture is changed to the posture B. Then, the first link10is flexed around the first axis S1, which serves as the supporting point, under the guide of the guide long hole11band first guide hole2b1, by rotating the rotator21in a clockwise direction. Thereby, the finger link F1is flexed to a direction approaching to a palm.

As described above, in the robot hand apparatus1of the present embodiment, the actuation of the finger link F1around each of the first axis S1and the second axis S2is enabled. Therefore, the number of the parts can be reduced, and the reduction of the apparatus's weight can be enabled. Furthermore, since the weight at tip of the arm R3can be reduced, the decreasing of the moment of inertia can be achieved.

In the present embodiment, additionally, as shown inFIG. 4, since the slide within the second guide path2bof the bearing60is enabled by providing the bearing60to the control axis42, the smooth actuation of the finger link F1can be constantly achieved. Additionally, the adoption of the bearing60enables much smooth actuation of the finger link F1and the smooth actuation at the inflexion point between the first guide hole2b1and the second guide hole2b2.

Still furthermore, since the connection link22and the elevating member30are joined through the control axis42, the reducing of the number of the parts can be achieved. Here, the connection link22and the elevating member30may be joined using the other axis other than the control axis42.

FIG. 8AandFIG. 8Bare respectively a perspective view showing the mechanism linking directly the first link and the finger link. In this embodiment, the finger link F1of each mechanism is directly actuated by a torque of the control axis42, and is not indirectly actuated by a torque of the control axis42that is transferred through the arm member31and the elevating member30.

Here, as for the other sections which are not indicated in figure, it is regarded as the same as the above described embodiment, and the explanation thereof will be omitted.

In the embodiment shown inFIG. 8A, by providing the sphere42aat the tip of the control axis42, the sphere42ais rotatably engaged with the pin connection holes50a1and50a1disposed on the finger link F1. In the case of the embodiment shown inFIG. 8B, a coupling42b, to which pin insertion hole42b1is formed, is provided to the tip of the control axis42, and the coupling42brotatably connects with the pin connection holes50a1and50a1through a pin46.

Here, in the case ofFIG. 8A, the pin connection hole50a1is not always a through hole, and this pin connection hole50a1may be a bottomed hole.

As for both embodiments shown inFIG. 8AandFIG. 8B, the finger link F1is rotated around the connection hole50a2(the second axis S2), which serves as a supporting point, by the up-and-down directional movement of the control axis42that is caused in accordance with the actuation of the connection link22(not shown). By directly actuating the finger link F1by the control axis42, the omission of the elevating member30and the arm member31is enabled. Thereby, further reducing of the number of the parts can be enabled.

FIG. 9is a schematic view showing robot hand apparatus1A, in which the second link is simplified.FIG. 9Aindicates the motion around a first axis, andFIG. 9Bindicates the motion around a second axis.

As shown inFIG. 9A, the robot hand apparatus1A has a first link10A, a second link20A, and a finger link F1.

The first link10A has a guide long hole11c(first guide path) and is rotatable around the rigid axis40A disposed on the base (not shown). Additionally, the finger link F1rotatably connects with the first link10A through the connection pin45A.

One end of the second link20A is supported by the actuation shaft g and is allowed the rotation around the actuation shaft g, and the other end thereof is fixed to the control axis42A, which is inserted into the guide long hole11cso that the control axis42A is moveable along the guide-long-hole11c.

Additionally, as shown inFIG. 9B, the control axis42A rotatably connects with the finger link F1through the elevating member30A.

In the robot hand apparatus1A, as shown inFIG. 9A, since second link20A rotates in an anti clockwise direction by the torque of the actuation shaft g, the control axis42A moves within the long guide hole11cof the first link10A from one end to the other end.

Thereby, the finger link F1is rotated around the rigid axis40A which serves as first axis, and is moved to the position shown by dot dash line. That is, the finger link F1is actuated as if a thumb moves to the position where a thumb is directed upwardly.

In this occasion, as shown inFIG. 9B, the finger link F1is pushed upwardly by the elevating member30A in compliance with the torque during the upward movement of the control axis42A. Thus, the finger link F1is rotated around the connection pin45A, which serves as second axis, and is moved to the position shown by dot dash line. That is, the finger link F1is actuated as if a thumb moves to the position where a thumb is directed to an outside.

Here, the present invention is not limited to the above described embodiments, and the shape of the second guide path2bmay be changed as appropriate. As described above, the second guide path2bis not limited to the second guide path consisting of the curved first guide hole2b1and the straight second guide hole2b2. The shape of the second guide path2bmay be straight or curves as a whole.

In the above described embodiment, the mechanism, in which the rigid axis40, pins43and44, and the connection pin45are used, is adopted for each connection mechanism, i.e. the connection mechanism between the base2and the first link10; the connection mechanism between the elevating member30and the arm member31; the connection mechanisms between the arm member31and the finger link F1; and the connection mechanism between the first link10and the finger link F1. Two joining members may be joined each other by rotatably connecting a concave portion and a convex portion which are provided on two joining members.