Robot joint driving apparatus, robot having the same and cable linkage method of robot joint driving apparatus
A robot joint driving apparatus has an improved structure, a robot having the same, and a cable linkage method of the robot joint driving apparatus. In the robot joint driving apparatus, lines of a cable to drive a robot joint unit are connected plural times in parallel, thereby increasing torsional stiffness of the robot joint unit. Further, a cable fixing unit is provided on an output pulley, thereby preventing slippage of the cable on the output pulley. Moreover, the overall size of the robot joint driving apparatus is reduced due to an improved power transmission structure from a driving motor to the output pulley.
1. A robot joint driving apparatus comprising:
a driving motor rotated in regular and reverse directions;
a movable member to move rectilinearly through driving force transmitted from the driving motor;
a cable assembly connected to the movable member in both directions;
an idle pulley to contact one end of the cable assembly and rotated; and
an output pulley to contact the other end of the cable assembly and rotated to directly drive a joint unit,
wherein lines of the cable assembly are connected at least once in parallel among the idle pulley, the movable member, and the output pulley,
wherein the cable assembly includes a first line at one side of the cable assembly provided between the output pulley and the idle pulley, a second line provided adjacent to the first line in parallel with the first line, a third line provided adjacent to the second line in parallel with the second line, and a fourth line provided adjacent to the third line in parallel with the third line.
2. The robot joint driving apparatus according to claim 1 , wherein the cable assembly forms a closed loop, and both ends of the cable assembly are connected by a connection loop sleeve pressing the cable assembly.
3. The robot joint driving apparatus according to claim 1 , wherein the output pulley includes a cable fixing unit to prevent slippage of the cable assembly on the output pulley.
4. The robot joint driving apparatus according to claim 3 , wherein the cable fixing unit includes cable guide brackets to guide the cable assembly to enable the cable assembly to be arranged in parallel with the axial direction of the output pulley.
5. The robot joint driving apparatus according to claim 3 , wherein fixing loop sleeves pressing the cable assembly are inserted into parts of the cable assembly contacting the output pulley, and the cable fixing unit includes spacers to fix the fixing loop sleeves to the output pulley.
6. The robot joint driving apparatus according to claim 1 , further comprising a ball screw unit to which the movable member is screw-connected.
7. The robot joint driving apparatus according to claim 6 , further comprising a ball screw unit frame to which the ball screw unit is connected,
wherein the ball screw unit frame includes a guide slot to guide the movable member to prevent rotation of the movable member.
8. The robot joint driving apparatus according to claim 7 , wherein the movable member includes at least one guide bearing movably inserted into the guide slot.
9. The robot joint driving apparatus according to claim 1 , wherein the movable member includes mounting blocks, to which the cable assembly is connected, forming a body of the movable member, and the mounting blocks include cable connection parts provided to enable the cable assembly to be connected thereto.
10. The robot joint driving apparatus according to claim 9 , wherein the cable connection parts include first guide pins connected to the mounting blocks such that the lines of the cable assembly are connected to the first guide pins in parallel, and second guide pins connected to the mounting blocks such that intervals between the lines of the cable assembly are reduced.