This application claims priority under 35 U.S.C. §119(a) from Korean Patent Application No. 2008-0063006, filed Jun. 30, 2008, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field
The present general inventive concept relates to a driving apparatus and a robot having the same, and more particularly to a driving apparatus, in which pressure units provide tensile strength to prevent a generation of slip of a cable from a driving unit and a driven unit, and a robot having the driving apparatus.
2. Description of the Related Art
In general, driving apparatuses refer to apparatuses, which drive a power tool, such as an instrument or a measuring machine. The driving apparatuses transmit rotary force generated by an internal combustion engine or a motor to the power tool such that the power tool performs an intended motion.
Among the driving apparatuses, there is a driving apparatus, which transmits rotary force using a capstan method. The capstan-type driving apparatus transmits power including a rotary force using a cable. That is, the capstan type driving apparatus transmits the rotary force from a driving unit to a driven unit by winding the cable on a plurality of shafts or unwinding the cable from the shafts.
As a technique relating to robots has been developed now, an attempt to develop humanoid robots, which have the similar appearance to that of a human being, rather than industrial robots, which conventionally performed a specific motion, have been made.
In order to manufacture a humanoid robot, effectively transmitting rotary force for operating arms, legs, etc., in a minimum space is necessary, and in order to satisfy the above requirement, the capstan method has been introduced.
In a capstan-type driving apparatus using a cable, when the cable is loosened, slip of the cable from shafts, on which the cable is wound, is generated, and thus disturbs a smooth transmission of a rotary force. Thus, a designated intensity or more of tensile strength must be applied to the cable.
However, the conventional driving apparatus prevents the generation of slip of the cable from the shafts by increasing a number of winding times of the cable on the shafts and causes the shafts to have a long length, thus having an increased overall size.
The present general inventive concept provides a driving apparatus and a robot having the same, in which a cable transmitting the rotary force of a driving unit to a driven unit has sufficient tensile strength and thus prevents a generation of slip of the cable from the driving unit and the driven unit to allow the rotary force to be transmitted to the driven unit without a loss.
Additional aspects and utilities of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.
The foregoing and/or other aspects and utilities of the general inventive concept may be achieved by providing a driving apparatus including a driving unit, a driven unit separated from the driving unit at a separation space so as not to contact the driving unit, and rotated by rotary force generated from the driving unit, a cable connecting the driving unit and the driven unit, and to transmit the rotary force to the driven unit, and pressure units provided in the separation space, and to pressurize the cable in a direction of approaching opposite portions of the cable to each other to generate a tensile strength of the cable.
The pressure units may be provided to pressurize the cable inwardly from outside of a loop formed by the cable.
A groove-shaped guide corresponding to a diameter of the cable to guide a winding position of the cable may be provided on an outer circumferential surface of at least one of the driving unit, the driven unit, and the pressure units.
The guide provided on the driven unit may include a parallel portion provided on the outer circumferential surface of the driven unit in a direction perpendicular to an axial direction of the driven unit, and a shift portion moving the winding position of the cable in parallel in the axial direction of the driven unit.
The driven unit may have a cylindrical drum shape, and may include a level portion having a level outer circumferential surface, and the shift portion may be provided on the level portion.
The shift portion may include inclined portions inclined at a designated angle against the guide provided on the parallel portion, and the inclined portions may move the cable in parallel by as long as at least the diameter of the cable.
The pressure units may be prepared in a pair, and each of the guides respectively provided on the pressure units may include a shift portion moving the winding position of the cable in parallel in the axial direction of the pressure units by as long as half of the diameter of the cable.
Each of the pressure units may have a cylindrical roller shape.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a robot having at least one driving apparatus, the driving apparatus including a driving unit to generate a rotary force, a driven unit separated from the driving unit at a separation space so as not to contact the driving unit, and rotated by rotary force generated from the driving unit, a cable to transmit the rotary force to the driven unit, and a pair of pressure units provided in the separation space, and to pressurize the cable inwardly from outside of a loop formed by the cable to increase contact between the cable and at least one of the driving unit and the driven unit.
A groove-shaped guide corresponding to the diameter of the cable to guide the winding position of the cable may be provided on the outer circumferential surface of at least one of the driving unit, the driven unit, and the pressure units.
The guide provided on the driven unit may include a parallel portion provided on the outer circumferential surface of the driven unit in a direction perpendicular to the axial direction of the driven unit, and a shift portion moving the winding position of the cable in parallel in the axial direction of the driven unit.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a robot having at least one driving apparatus, the driving apparatus including a driving unit to generate a rotary force, a driven unit separated from the driving unit at a separation space so as not to contact the driving unit, and rotated by rotary force generated from the driving unit, a cable to transmit the rotary force to the driven unit, a pair of pressure units provided in the separation space, and to pressurize the cable inwardly from outside of a loop formed by the cable to increase contact between the cable and at least one of the driving unit and the driven unit, and a groove-shaped shift portion provided on an outer circumferential surface of the driven unit to move the winding position of the cable in parallel in an axial direction of the driven unit.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a robot having at least one driving apparatus, the driving apparatus including a driving unit to generate a rotary force, a driven unit separated from the driving unit at a separation space so as not to contact the driving unit, and rotated by the rotary force generated from the driving unit, a cable to transmit the rotary force to the driven unit, a pair of pressure units provided in the separation space, and to pressurize the cable inwardly from outside of a loop formed by the cable to increase contact between the cable and at least one of the driving unit and the driven unit, and groove-shaped shift portions respectively provided on outer circumferential surfaces of the pressure units to move a winding position of the cable in parallel in an axial direction of the pressure units.
The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a driving apparatus usable with a robot, the driving apparatus including a driven unit to drive the robot, a driving unit to generate a force, a cable to transmit the force from the driving unit to the driven unit, and one or more pressure units to pressurize the cable by increasing contact between the cable and at least one of the driving unit and the driven unit.
The driving apparatus may further include a groove-shaped shift portion provided on an outer circumferential surface of the driven unit to move to receive the cable.
These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:
Reference will now be made in detail to embodiments of the present general inventive concept, an example of which is illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the present general inventive concept by referring to the annexed drawings.
As illustrated in
The driving apparatus 20 generates and transmits force, which causes the robot 10 to perform a motion. The driving apparatus 20 may be used at any portion of the robot 10, in which a motion is performed. However, for convenience of description, the driving apparatus 20, which is provided at a connection portion between the torso 14 and the leg 16, i.e., a hip joint 15, will be described unless a special portion is referred to. When a control unit (not illustrated) applies a control signal to move the robot 10 forward or backward to a motor 21 (
As illustrated in
The driving unit 30 is connected to a motor shaft (not illustrated), and is rotated by the rotary force generated from the motor 21. That is, the driving unit 30 generates force to operate the driving apparatus 20. The driving unit 30 includes a motor connection portion 32 connected to the motor 21 provided on the torso 14 (
The driving shaft 34 is extended from the motor connection portion 32, and serves to substantially transmit rotary force. A length of the driving shaft 34 depends on a number of winding times of the cable 50 on the driving shaft 34. That is, when the number of winding times of the cable 50 on the driving shaft 34 is increased, the length of the driving shaft 34 is relatively increased, and when the number of winding times of the cable 50 on the driving shaft 34 is decreased, the length of the driving shaft 34 is relatively decreased. Further, when the number of winding times of the cable 50 on the driving shaft 34 is increased, although tensile strength applied to the cable 50 is relatively low, the generation of slip is reduced due to increased frictional force. However, when the number of winding times of the cable 50 on the driving shaft 34 is increased, the length of the driving shaft 34 is relatively increased, and thus an overall size of the driving apparatus 20 is increased. In the present embodiment, since the pressure units 60 pressurize the cable 50 and thus tensile strength is generated on the cable 50, the number of winding times of the cable 50 on the driving unit 30 and the driven unit 40 is decreased. Thereby, the overall size of the driving apparatus 20 is reduced. A driving shaft bearing 38 is connected to a portion of the driving shaft 34 at a side of the motor connection portion 32 so that a rotation of the driving shaft 34 can be smoothly performed, and a tip of the driving shaft 34 is supported by a first bracket 22. A first guide 36 is provided on the driving shaft 34.
The first guide 36 guides a position of the cable 50. The first guide 36 is a groove provided on a surface of the driving shaft 34 along a circumference of the driving shaft 34. The cable 50 contacts the driving shaft 34 along the groove-shaped first guide 36. Since the cable 50 is guided by the first guide 36, the cable 50 is not entangled or is not separated from the driving shaft 34 although the driving shaft 34 continuously rotates.
The driven unit 40 receives the rotary force of the driving unit 30. The rotary force generated from the motor 21 rotates the driving unit 30, and the rotary force of the driving unit 30 is transmitted to the driven unit 40 by the cable 50. If the motor 21 is provided on the torso 14 (
The shift portion 48 is provided on the level portion 42 of the driven drum 41. One strand of the cable 50 repeatedly reciprocates between an outer surface of the driving shaft 34 of the driving unit 30 and the outer surface of the driven drum 41 of the driven unit 40, and is thus wound on the driving shaft 34 and the driven drum 41. That is, one strand of the cable 50 reciprocates between the driving unit 30 and the driven unit 40, and forms one closed loop. Since one stand of the cable 50 reciprocates between the driving shaft 34 and the driven drum 41 and is wound on the driving shaft 34 and the driven drum 41, the strand of the cable 50 must be wound at an interval of at least a width of the cable 50 so as not to be entangled. Inclined portions 47 are provided on the second guide 46 at the shift portion 48. The inclined portions 47 are inclined by as much as at least the width of the cable 50. The strand of the cable 50 wound along the second guide 46 is inclined at the inclined portions 47 of the shift portion 48. Thus, the strand of the cable 50 can be wound in parallel without entanglement. A cover 49 is provided on the shift portion 48.
The cover 49 is connected to the shift portion 48. Grooves 44 corresponding to a shape of the shift portion 48 having the inclined portions 47 are provided on the inner surface of the cover 49.
One strand of the cable 50 reciprocates between the driving unit 30 and the driven unit 40, and is wound on the driving unit 30 and the driven unit 40. Although the embodiment illustrated in
The pressure units 60 pressurize the cable 50 so that the cable 50 has tensile strength. The pressure units 60 are provided at both sides of the driving unit 30, and thus are prepared in a pair. Although the embodiment illustrated in
As illustrated in
The tensile strength of the cable 50 is increased by pressurizing the cable 50 in the pressurization direction (F) using the pressure units 60. That is, the tensile strength of the cable 50 is increased when the pressure units 60 pressurize the cable 50, which is wound between the driving unit 30 and the driven unit 40 to form a closed loop, in a direction to reduce a diameter of the closed loop of the cable 50 in the separation space (S). When the tensile strength of the cable 50 is increased, contact force between the cable 50 and the driving unit 30 and between the cable 50 and the driven unit 40 is increased. When the contact force is increased, a possibility of slip of the cable 50 from the surfaces of the driving unit 30 and the driven unit 40 is reduced. Although the driving unit 30 rotates, when the cable 50 is slipped from the surfaces of the driving unit 30 and the driven unit 40, the rotary force of the driving unit 30 cannot be transmitted. Thus, the maintenance of the tensile strength of the cable 50 to prevent the slip of the cable 50 is an important design factor to increase the power transmission efficiency of the driving apparatus 20. The pressure units 60 in accordance with the embodiment illustrated in
The contact lengths between the cable 50 and the driving unit 30 and between the cable 50 and the driven unit 40 are increased by pressurizing the cable 50 in the pressurization direction (F) using the pressure units 60. Accordingly, a contact angle (a) is increased, seen from the side surface of the driven unit 40. In case that the pressure units 60 are not provided, a space formed by the driving unit 30, the driven unit 40, and the cable 50 in the separation space (S) is relatively increased. In case that the pressure units 60 pressurize the cable 50 in the pressurization direction (F), the contact lengths between the cable 50 and the driving unit 30 and between the cable 50 and the driven unit 40 are increased and thus the contact angle (a) is increased. When the contact lengths and the contact angle (a) are increased by the pressure units 60, frictional force between the cable 50 and the driving unit 30 and between the cable 50 and the driven unit 40 is increased. When the frictional force is increased, the generation of the slip of the cable 50 is reduced and thus the power transmission efficiency of the driving apparatus 20 is increased.
Hereinafter, the operation of the above driving apparatus 20 in accordance with the embodiment as illustrated in
Here, on condition that the leg 16 has already moved forward by the operation of the driving apparatus 20, the operation of the driving apparatus 20 to move the leg 16 backward will be described.
As illustrated in
As illustrated in
In a driving apparatus 20a in accordance with the embodiment illustrated in
The pressure units 60a in a pair are divided into first and second pressure units 61a and 62a, and the shift portions 48a are respectively provided on the first and second pressure units 61a and 62a. Inclined portions 47a, which move the strand of the cable 50 in parallel by as long as the half of the thickness of the cable 50, are provided on each of the shift portions 48a. The cable 50 is moved by as long as the half of the thickness of the cable 50 by the inclined portions 47a of the first pressure unit 61a, and is moved again by as long as the half of the thickness of the cable 50 by the inclined portions 47a of the second pressure unit 62a . Thus, when the cable 50 passes through the pressure units 60a in a pair, the cable 50 is moved in parallel by as long as the thickness of the cable 50.
As apparent from the above description, the present general inventive concept provides a driving apparatus and a robot having the same, in which a cable transmitting the rotary force of a driving unit to a driven unit has sufficient tensile strength and thus prevents a generation of slip of the cable from the driving unit or the driven unit to allow the rotary force to be transmitted to the driven unit without a loss.
Although various embodiments of the present general inventive concept have been illustrated and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents.
Number | Date | Country | Kind |
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2008-63006 | Jun 2008 | KR | national |