Patent Application
20140197652
The present invention relates to an end effector module, in particular to the end effector module having a plurality of joint shafts and a driving device installed at each joint shaft and provided for driving and fine-tuning the joint shafts to facilitate clamping and sucking an object from different oriented surfaces.
In a conventional end effector structure as disclosed in U.S. Pat. No. 5,501,498, the frictional force between an end joint shaft of a robotic finger and an object is used for clamping the object, but the clamping effect is relatively low due to factors such as the clamping angle, the size and the surface smoothness of the object.
In another conventional end effector structure as disclosed in U.S. Pat. Publication No. 2010/0156125, a combination of air pressure, a link rod and a spring is provided to drive a robotic finger to turn pivotally in order to achieve the operation of clamping an object, and the conventional end effector has a suction device installed at an end of a joint shaft for sucking the object by a suction, and this structure overcomes the drawback of the aforementioned conventional end effector structure.
However, this conventional end effector structure has three joint shafts of each robotic finger, which is similar to a human finger that can be bent in sections, and an end joint shaft comes with a suction design, so that the robotic finger can be bent or pivotally turned in a direction towards a palm similar to that of human fingers. In other words, the motion of the robotic finger has only one degree of freedom and fails to make a fine angular adjustment of the joint shaft, and it is relatively difficult to move a suction device to a position corresponding to the normal direction of the surface of the object or approach a selected suction point along the normal direction to suck the object. As a result, such conventional end effector structure has a low clamping effect. In summation, this conventional end effector is applicable for grasping or sucking an object of a special shape and incapable of selecting the suction point precisely according to the direction of approaching an object in the normal direction and clamping the object.
In another conventional end effector structure as disclosed in Japan Pat. Publication No. P2010-155331A, a special design of a suction device and its robotic hand is adopted, so that a suction device can approach the normal direction to suck the object precisely, but the robotic hand is a fixed structure and incapable of clamping or sucking objects of different shapes.
In view of the aforementioned problems, it is a primary objective of the present invention to provide an end effector module that drives a gear by a motor installed at each joint shaft in order to drive a whole robotic finger to rotate while driving another gear to drive the next joint shaft to bend, so that the robotic finger of the present invention has a plural degrees of freedom and is applicable for clamping and sucking various objects with different oriented surfaces through a suction device installed at the end of each joint shaft.
To achieve the foregoing objective, the present invention provides an end effector module, comprising: a palm base, a plurality of robotic fingers, extended from a same side of the palm base, and each robotic finger being formed by sequentially and pivotally coupling a start joint shaft, a first middle joint shaft, a second middle joint shaft and an end joint shaft with each other, wherein: the start joint shaft has a first driving mechanism for driving the first middle joint shaft to turn pivotally and bend with respect to the start joint shaft, as well as driving the first middle joint shaft to turn the second middle joint shaft and the end joint shaft altogether; the first middle joint shaft has a second driving mechanism for driving the second middle joint shaft to turn pivotally and bend with respect to the first middle joint shaft; the second middle joint shaft has a third driving mechanism for driving the end joint shaft to turn pivotally and bend with respect to the second middle joint shaft; thereby, each robotic finger is bent by the rotation of the robotic finger and the pivotal turning of each joint shaft to adjust the position of a suction device installed on the end joint shaft, so as to move the suction device to the normal direction of a selected suction point of a surface of a clamped object and approach the normal direction to suck the object.
The technical characteristics of the present invention will become apparent with the detailed description of the preferred embodiments accompanied with the illustration of related drawings as follows.
With reference to
The start joint shaft 2 is extended from the palm base 1 and has a casing 21, and a first motor 22 and a second motor 23 installed on adjacent sides of the casing 21 respectively, wherein a first transmission shaft 221 is extended from the first motor 22, and a second transmission shaft 231 is extended from the second motor 23, and the first transmission shaft 221 is axially fixed to an active gear 24, such that the first motor 22 can drive the active gear 24 to rotate directly, and the second transmission shaft 231 has a passive gear 25 pivotally coupled by a bearing 251, such that the second motor 23 does not drive the passive gear 25 to rotate directly. In this preferred embodiment, each of the first motor 22 and the second motor 23 is coupled to a speed reducer 26, 27 first, and then coupled to the corresponding gear 24, 25 for adjusting the rotation speed of each gear 24, 25 driven by the motor. In
The first middle joint shaft 3 also has a casing 31 with a connecting portion 32 formed at an end, and the connecting portion 32 is composed of a pair of columns 321 arranged with an interval apart from one another and a pivot 33 is transversely passed through the two columns 321 and a gap 322 between the two columns 321 to fix with the connecting portion 32, and the connecting end 2311 of the second transmission shaft 231 is extended into the gap 322, and the pivot 33 is passed through the pivot hole 2312 of the connecting end 2311 and rotated in the pivot hole 2312, so as to drive the first middle joint shaft 3 to turn pivotally. A second bevel gear 34 is pivotally coupled to an end of the pivot 33 and engaged with the first bevel gear 252, and the second bevel gear 34 can be driven to rotate through the transmission by the first motor 22, so that the rotation of the first transmission shaft 221, the active gear 24, the passive gear 25 and the first bevel gear 252, and the pivot 33 is driven to rotate to turn the first middle joint shaft 3 pivotally. In this preferred embodiment, the pivot 33 of the connecting portion 32 of the first middle joint shaft 3 has a seventh bevel gear 35 installed at a position opposite to the second bevel gear 34 by a bearing 351 and engaged with the first bevel gear 252 for balancing the rotational inertia of the second bevel gear 34 on the pivot 33, wherein the seventh bevel gear 35 can be driven by the first bevel gear 252 to rotate idly with respect to the pivot 33 without affecting the overall operation of the end effector. The first middle joint shaft 3 includes a third motor 36 installed in a casing 31 of the first middle joint shaft 3 and coupled to a speed reducer 37 and then coupled to a third bevel gear 38, and the casing 31 of the first middle joint shaft 3 has a pivoting portion 39 disposed at a position proximate to the third bevel gear 38 for downwardly and pivotally coupling the second middle joint shaft 4.
The second middle joint shaft 4 also has a casing 41 with a connecting portion 42 disposed at an end, and the connecting portion 42 is composed of a pair of columns 421 arranged with an interval apart, and a transverse pivot 43 is installed on the two columns 421 and passed through the pivoting portion 39 of the first middle joint shaft 3, so that the second middle joint shaft 4 can be turned pivotally with respect to the first middle joint shaft 3, and the pivot 43 has a fourth bevel gear 44 engaged with the third bevel gear 38, such that the rotation of the third bevel gear 38 can drive the fourth bevel gear 44 to rotate the pivot 43, so as to turn the second middle joint shaft 4 pivotally. In addition, the second middle joint shaft 4 has a fourth motor 45 installed in the casing 41 and coupled to a speed reducer 46 and then coupled to a fifth bevel gear 47, and the casing 41 of the second middle joint shaft 4 has a pivoting portion 48 disposed at a position proximate to the fifth bevel gear 47 for downwardly and pivotally coupling the end joint shaft 5.
A connecting portion 51 is formed at an end of the end joint shaft 5 and composed of a pair of wing portions 511 disposed at both sides of the end joint shaft 5 respectively, and a transverse pivot 52 is fixed onto the two wing portions 511 and passed through the pivoting portion 48 of the second middle joint shaft 4, so that the end joint shaft 5 can be turned pivotally with respect to the second middle joint shaft 4, and the pivot 52 has a sixth bevel gear 53 engaged with the fifth bevel gear 47, such that the rotation of the fifth bevel gear 47 drives the sixth bevel gear 53 to rotate the pivot 52, so as to turn the end joint shaft 5 pivotally. In addition, the end joint shaft 5 has a suction device 54 installed at an end opposite to the connecting portion 51 for sucking a surface of an object to provide a more secured grasp.
In one of the robotic fingers of the end effector module in accordance to a preferred embodiment of the present invention as shown in
1. In
2. In
3. In
The aforementioned three ways of movements can control the robotic fingers of the end effector to rotate or bend, so that each robotic finger is a module with the movement of four degrees of freedom, and the three joint shafts can control the rotation of the gears by separate motors to fine-tune the position of the suction device installed at the end joint shaft, and the robotic finger can be moved precisely to the normal direction N of a selected suction point P on a surface of a clamped object O as shown in
In addition, the suction device 54 includes a sucker 541 and a circuit 542, and the movement is the same as described above. In the robotic finger A of the end effector having four degrees of freedom, the sucker 541 can approaches along the normal direction of the selected suction point on the surface of the object, and the circuit 542 controls the sucker 541 to suck the object. The suction device 54 can be operated with two modes as described below 1. The sucker 541 of the suction device 54 is comprised of electromagnets for sucking a magnetic conductive object. After the suction device 54 is moved to an appropriate position of the clamping object, current is passed through the circuit 542 to produce magnetism to the sucker 541, so that magnetic forces so produced can suck the clamped object O securely 2.
The circuit 542 of the suction device 54 is an air duct instead, wherein the air duct can blow and suck air to produce suction to the sucker 541 to suck the clamped object O. When the air duct sucks air, the air pressure inside the sucker 541 is reduced to produce a suction to the clamped object O. Further, the suction device 54 can apply the Bernoulli's Law. When the air duct blows air to the clamped object O, the airflows flow through the surfaces of the clamped object O in different speeds to produce a pressure difference so as to produce a force to push the clamped object O towards the sucker 541 and attach the sucker 541 onto the clamped object O.
