Dual arm robot
View Patent ↗A dual arm robot assembly has two arms each having a set of joint/link pairs that, in conjunction with an actuator assembly, define at least three degrees of freedom to provide independent horizontal translation and rotation of a distalmost link. A vertical motion mechanism is also provided.
1. A robot assembly for manipulating one or more substrates, comprising:
a first arm and a second arm supported by a column;
the first arm comprising a first limb, the first limb comprising a first set of three revolute joint/link pairs serially connected in an open kinematic chain to provide translation and rotation of a distalmost link of the first limb in a horizontal plane;
the second arm comprising a second limb, the second limb comprising a second set of three revolute joint/link pairs serially connected in an open kinematic chain to provide translation and rotation of a distalmost link of the second limb in a horizontal plane;
the first limb and the second limb having proximal revolute joints having a common vertical axis of rotation;
an actuator assembly coupled to the first set of revolute joint/link pairs and to the second set of revolute joint/link pairs to effect rotation and translation of the distalmost links of the first limb and the second limb, the actuator assembly comprising:
four hollow shafts concentrically disposed about the common vertical axis of rotation,
first and second motors operatively coupled to a most proximal joint/link pair of the first set of revolute joint/link pairs of the first arm and to an outermost two of the hollow shafts,
the first and second motors being arranged so that an outer perimeter of a stator of the first motor is concentric with an outer perimeter of a stator of the second motor to form a first motor module where the first and second motors are arranged concentrically to the outermost two of the hollow shafts,
third and forth motors operatively coupled to a most proximal joint/link pair of the second set of revolute joint/link pairs of the second arm and to an innermost two of the hollow shafts,
the third and fourth motors being arranged so that an outer perimeter of a stator of the third motor is concentric with an outer perimeter of a stator of the fourth motor to form a second motor module where the third and fourth motors are arranged concentrically to the innermost two of the hollow shafts where the first motor is radially nested with the second motor and the third motor is radially nested with the fourth motor, and
the second motor module being disposed below the first motor module in a motor package enclosure; and
the first limb and the second limb defining, in conjunction with the actuator assembly, four degrees of freedom, whereby the distalmost links of the first limb and the second limb are independently horizontally translatable for extension and retraction, the first limb and the second limb are independently rotatable over the common vertical axis of rotation, and the distalmost joints of the first and second limbs are radially translatable along a radial horizontal line extending over the common vertical axis of rotation.
2. The assembly of claim 1 , wherein the first arm and the second arm further comprise a shared prismatic joint and link configured to provide vertical displacement.
3. The assembly of claim 2 , wherein the prismatic joint and link are supported by the column.
4. The assembly of claim 2 , wherein the prismatic joint and link are rotatably mounted on a supporting surface.
5. The assembly of claim 2 , wherein the prismatic joint and link are fixedly mounted on a supporting surface.
6. The assembly of claim 1 , wherein the distalmost link of the first set of revolute joint/link pairs comprises a first end effector mounting flange and the distalmost link of the second set of revolute joint/link pairs comprises a second end effector mounting flange, the first set of revolute joint/link pairs and the second set of revolute joint/link pairs configured to vertically offset the first end effector mounting flange from the second end effector mounting flange.
7. The assembly of claim 1 , wherein the first set of joint/link pairs of the first limb comprises a first shoulder revolute joint and a first inner link, a first elbow revolute joint and a first outer link, and a first wrist revolute joint and a first end effector mounting flange, the first end effector mounting flange comprising the distalmost link of the first limb; and
wherein the second set of joint/link pairs of the second limb comprises a second shoulder revolute joint and a second inner link, a second elbow revolute joint and a second outer link, and a second wrist revolute joint and a second end effector mounting flange, the second end effector mounting flange comprising the distalmost link of the second limb.
8. The assembly of claim 7 , wherein the first and second motors are coupled to the first shoulder joint and to the first inner link respectively, and the third and forth motors are coupled to the second shoulder joint and to the second inner link respectively.
9. The assembly of claim 7 , wherein the first inner link comprises a belt fixed for travel about a first pulley at the shoulder joint and a second pulley at the elbow joint, and the first outer link comprises a belt fixed for travel about a third pulley at the elbow joint and a fourth pulley at the wrist joint.
10. The assembly of claim 9 , wherein a ratio of diameters of the first pulley to the second pulley is 2:1.
11. The assembly of claim 9 , wherein a ratio of diameters of the first pulley to the second pulley is 1:1.
12. The assembly of claim 9 , wherein a ratio of diameters of the third pulley to the fourth pulley is 1:2.
13. The assembly of claim 9 , wherein the second inner link comprises a belt fixed for travel about a fifth pulley at the shoulder joint and a sixth pulley at the elbow joint, and the second outer link comprises a belt fixed for travel about a seventh pulley at the elbow joint and an eighth pulley at the wrist joint.
14. The assembly of claim 13 , wherein a ratio of diameters of the fifth pulley to the sixth pulley is 2:1.
15. The assembly of claim 13 , wherein a ratio of diameters of the fifth pulley to the sixth pulley is 1:1.
16. The assembly of claim 13 , wherein a ratio of diameters of the seventh pulley to the eighth pulley is 1:2.
17. The assembly of claim 7 , wherein one of the first and second elbow joints has a greater vertical extent than another of the first and second elbow joints sufficient to vertically offset the end effector mounting flanges of the first and second limbs, whereby collisions of the end effector mounting flanges are avoidable.
18. The assembly of claim 7 , wherein one of the first limb and the second limb is shorter than another of the first limb and the second limb sufficient to avoid collision of intermediate portions of the first limb and the second limb during rotation about the shared vertical axes of the first and second shoulder joints.
19. The assembly of claim 1 , wherein the motor package enclosure is sealed to maintain a vacuum therein.
20. The assembly of claim 1 , wherein the distalmost links comprise end effector mounting flanges configured to support end effectors for supporting a substrate.
21. The assembly of claim 1 , wherein the distalmost links comprise end effector mounting flanges configured to support semiconductor wafer handling end effectors.
22. The assembly of claim 1 , further comprising a housing arranged to sustain a vacuum environment enclosing the actuator assembly.
23. The robot assembly of claim 1 , further comprising a controller operatively coupled to the actuator assembly.