Accessory interfaces for a mobile manipulator robot
Consistent connection strategies for coupling accessories to a robot can help achieve certain objectives, e.g., to tolerate and correct misalignment during coupling of the accessory. In some embodiments, the connection strategy may enable certain accessories to connect to certain sides of a robot. When connected, an accessory may be rigid in yaw, lateral motion, and fore/aft motion, while remaining unconstrained in roll and pitch as well as vertical motion. A sensor may enable detection of the accessory, and a mechanical fuse may release the accessory when a force threshold is exceeded. A mechanical coupler of an accessory may include two connectors, each of which includes a receiving area configured to receive a pin on the robot and a latch configured to retain the pin within the receiving area. The pins (and the receiving areas) may be differently sized, and may be differently arranged.
1 . A mechanical coupler for coupling a robot and an accessory, the mechanical coupler comprising:
a first connector comprising:
a first receiving area configured to receive a first pin of the robot through a first opening, the first receiving area having at least one first dimension;
a first moveable latch configured to constrain motion of the first pin when the first pin is received within the first receiving area and when a first protrusion of the first moveable latch is disposed in the first opening;
a first mechanical fuse including a flexure configured to enable motion of the first moveable latch to release the first pin at a first load; and
a second mechanical fuse including a break-off pin configured to break at a second load greater than the first load; and
a second connector comprising:
a second receiving area configured to receive a second pin of the robot through a second opening, the second receiving area having at least one second dimension different from the at least one first dimension; and
a second moveable latch configured to constrain motion of the second pin when the second pin is received within the second receiving area and when a second protrusion of the second moveable latch is disposed in the second opening,
wherein the mechanical coupler is configured to constrain rotation between the accessory and the robot about a first axis and to constrain translation between the accessory and the robot along second and third axes, wherein the second and third axes are each perpendicular to the first axis, and wherein the third axis is perpendicular to the second axis.
2 . The mechanical coupler of claim 1 , wherein:
the first receiving area includes a round hole; and
the second receiving area includes a linear slot.
3 . The mechanical coupler of claim 1 , wherein the mechanical coupler is configured to enable translation between the accessory and the robot along the first axis and is configured to enable rotation between the accessory and the robot about the second and third axes.
4 . The mechanical coupler of claim 3 , wherein:
the mechanical coupler is configured to enable rotation between the accessory and the robot about the second axis of greater than or equal to −15 degrees and less than or equal to 15 degrees, and
the mechanical coupler is configured to enable rotation between the accessory and the robot about the third axis of greater than or equal to −15 degrees and less than or equal to 15 degrees.
5 . The mechanical coupler of claim 1 , further comprising:
a first torsional spring configured to rotate the first moveable latch relative to the first receiving area in a first direction; and
a second torsional spring configured to rotate the second moveable latch relative to the second receiving area in a second direction.
6 . The mechanical coupler of claim 5 , wherein:
the first moveable latch includes a first handle configured to enable rotation of the first moveable latch in a third direction opposite the first direction; and
the second moveable latch includes a second handle configured to enable rotation of the second moveable latch in a fourth direction opposite the second direction.
7 . The mechanical coupler of claim 1 , further comprising a detectable component configured to be detected when the robot and the accessory are coupled.
8 . The mechanical coupler of claim 7 , wherein the detectable component includes a magnet configured to be detected by a magnetic sensor on the robot.
9 . A cart accessory comprising:
a cart body having a flat surface on which one or more objects can be placed;
a plurality of wheels coupled to the cart body; and
the mechanical coupler of claim 1 .
10 . A kit, comprising:
an adjustable brace configured to couple to an expandable accessory and constrain expansion of at least a portion of the expandable accessory in a length direction of the expandable accessory; and
the mechanical coupler of claim 1 coupled to the adjustable brace.