Reaching mobile robots
A method of operating a robot includes driving a robot to approach a reach point, extending a manipulator arm forward of the reach point, and maintaining a drive wheel and a center of mass of the robot rearward of the reach point by moving a counter-balance body relative to an inverted pendulum body while extending the manipulator arm forward of the reach point. The robot includes the inverted pendulum body, the counter-balance body deposed on the inverted pendulum body, the manipulator arm connected to the inverted pendulum body, at least one leg having a first end prismatically coupled to the inverted pendulum body, and the drive wheel rotatably coupled to a second end of the at least one leg.
1. A method of operating a robot, the method comprising:
driving the robot across a surface to approach a reach point, the robot comprising:
an inverted pendulum body having first and second end portions;
a counter-balance body disposed on the inverted pendulum body and configured to move relative to the inverted pendulum body;
a manipulator arm having proximal and distal ends, the proximal end connected to the inverted pendulum body, the manipulator arm configured to move relative to the inverted pendulum body;
at least one leg having first and second ends, the first end of the at least one leg prismatically coupled to the second end portion of the inverted pendulum body; and
a drive wheel rotatably coupled to the second end of the at least one leg;
extending the manipulator arm forward of the reach point; and
maintaining the drive wheel and a center of mass of the robot rearward of the reach point by moving the counter-balance body relative to the inverted pendulum body while extending the manipulator arm forward of the reach point.
2. The method of claim 1 , wherein the robot further comprises an end effector disposed on the distal end of the manipulator arm, the method further comprising:
moving the manipulator arm to position the end effector relative to a target object forward of the reach point; and
taking hold of the target object with the end effector, while continuing to maintain the drive wheel and the center of mass of the robot rearward of the reach point.
3. The method of claim 2 , wherein the robot further comprises at least one perception sensor disposed on the end effector, the perception sensor configured to identify and/or localize the target object.
4. The method of claim 1 , wherein the at least one leg has a variable length between the first and second ends of the at least one leg, the method further comprising altering the length of the at least one leg to maintain the center of mass of the robot rearward of the reach point.
5. The method of claim 4 , wherein the at least one leg comprises:
a right leg having first and second ends, the first end of the right leg prismatically coupled to the second end potion of the inverted pendulum body, the right leg having a right drive wheel rotatably coupled to the second end of the right leg; and
a left leg having first and second ends, the first end of the left leg prismatically coupled to the second end potion of the inverted pendulum body, the left leg having a left drive wheel rotatably coupled to the second end of the left leg.
6. The method of claim 4 , wherein the at least one leg comprises:
an upper portion extending between the first end rotatably coupled to the second end portion of the inverted pendulum body and a knee joint; and
a lower portion extending between the knee joint and the second end rotatably coupled to the drive wheel, the lower portion rotatably coupled to the knee joint.
7. The method of claim 6 , wherein altering the length of the at least one leg comprises rotating the lower portion about the knee joint relative to the upper portion.
8. The method of claim 1 , wherein the counter-balance body is rotatably coupled to the second end portion of the inverted pendulum body.
9. The method of claim 1 , wherein the counter-balance body is rotatably coupled to the first end portion of the inverted pendulum body.
10. The method of claim 1 , wherein the manipulator arm is rotatably coupled to the first end portion of the inverted pendulum body.
11. The method of claim 1 , wherein the manipulator arm is rotatably coupled to the second end portion of the inverted pendulum body.
12. A robot comprising:
an inverted pendulum body having first and second end portions;
a counter-balance body coupled to the inverted pendulum body and configured to move relative to the inverted pendulum body;
a manipulator arm having proximal and distal ends, the proximal end connected to the inverted pendulum body, the manipulator arm configured to move relative to the inverted pendulum body;
at least one leg having first and second ends, the first end of the at least one leg prismatically coupled to the second end portion of the inverted pendulum body, the at least one leg having a variable length between the first and second ends;
a drive wheel rotatably coupled to the second end of the at least one leg; and
a controller in communication with the counter-balance body, the at least one leg, and the drive wheel, the controller configured to perform operations comprising:
driving the robot across a surface to approach a reach point;
extending the manipulator arm forward of the reach point; and
maintaining the drive wheel and a center of mass of the robot rearward of the reach point by moving the counter-balance body relative to the inverted pendulum body while extending the manipulator arm forward of the reach point.
13. The robot of claim 12 , further comprising an end effector disposed on the distal end of the manipulator arm, wherein the operations further comprise:
moving the manipulator arm to position the end effector relative to a target object forward of the reach point; and
taking hold of the target object with the end effector, while continuing to maintain the drive wheel and the center of mass of the robot rearward of the reach point.
14. The robot of claim 13 , further comprising at least one perception sensor disposed on the end effector, the perception sensor configured to identify and/or localize the target object.
15. The robot of claim 12 , wherein the at least one leg has a variable length between the first and second ends of the at least one leg, and wherein the operations further comprise altering the length of the at least one leg to maintain the center of mass of the robot rearward of the reach point.
16. The robot of claim 15 , wherein the at least one leg comprises:
a right leg having first and second ends, the first end of the right leg prismatically coupled to the second end potion of the inverted pendulum body, the right leg having a right drive wheel rotatably coupled to the second end of the right leg; and
a left leg having first and second ends, the first end of the left leg prismatically coupled to the second end potion of the inverted pendulum body, the left leg having a left drive wheel rotatably coupled to the second end of the left leg.
17. The robot of claim 15 , wherein the at least one leg comprises:
an upper portion extending between the first end prismatically coupled to the second end portion of the inverted pendulum body and a knee joint; and
a lower portion extending between the knee joint and the second end rotatably coupled to the drive wheel, the lower portion rotatably coupled to the knee joint.
18. The robot of claim 17 , wherein altering the length of the at least one leg comprises rotating the lower portion about the knee joint relative to the upper portion.
19. The robot of claim 12 , wherein the counter-balance body is rotatably coupled to the first end portion of the inverted pendulum body.
20. The robot of claim 12 , wherein the counter-balance body is rotatably coupled to the second end portion of the inverted pendulum body.
21. The robot of claim 12 , wherein the manipulator arm is rotatably coupled to the first end portion of the inverted pendulum body.
22. The robot of claim 12 , wherein the manipulator arm is rotatably coupled to the second end portion of the inverted pendulum body.