Climbing robot with compliant pinion drive
AssigneeWalmart Apollo, LLC
InventorsWilliam J. Fosnight, John G. Lert, Jr., Michael Duquette, Martin R. Elliott, Julian Warhurst, Charles W. Su, Alan Grant
Life of this patent
Estimating the term…
Abstract
An automated order fulfillment system and mobile robot are disclosed, where the mobile robot includes a compliant drive for moving between levels of a multilevel storage structure.
Claims22
A mobile robot configured to travel in a vertical or inclined passage within an automated retrieval and storage system, the passage comprising a linear drive mount, the mobile robot comprising:
- a compliant drive assembly for moving the mobile robot in the passage, the compliant drive assembly having:
- a hub for supporting a wheel, the hub comprising a first spline;
- a shaft having a second spline, the shaft configured to be rotated about an axis of rotation by a motor, the shaft further configured to be extended axially along the axis of rotation;
- a drive gear mounted on an end of the shaft, the drive gear configured to move into engagement with the linear drive mount upon extension of the shaft;
- wherein the first and second splines are configured to prevent jamming of the drive gear against the linear drive mount when the drive gear moves into engagement with the linear drive mount upon extension of the shaft, the first and second splines configured to prevent the jamming by providing rotational play between the first and second splines, the rotational play allowing a degree of free rotation of the drive gear relative to the linear drive mount.
An order fulfilment system, comprising:
- a multilevel storage structure having storage locations in different levels, and a vertical or inclined passage passing between the different levels, the passage comprising a linear drive mount along its length;
- and
- a mobile robot configured to travel between the levels in the passage, the mobile robot having:
- a motor mounted within the mobile robot, the motor comprising a first spline;
- a shaft having a second spline, the shaft configured to be rotated about an axis of rotation by the motor by the first spline of the motor exerting force on the second spline of the shaft, the shaft further configured to be extended axially along the axis of rotation;
- a drive gear mounted on an end of the shaft, the drive gear configured to move into engagement with the linear drive mount upon extension of the shaft;
- wherein the first and second splines are configured to prevent jamming of the drive gear against the linear drive mount when the drive gear moves into engagement with the linear drive mount upon extension of the shaft by providing rotational play between the first and second splines, the rotational play allowing a degree of free rotation of the drive gear relative to the linear drive mount.
A method of transporting a mobile robot along a vertical or inclined passage between storage levels in an order fulfillment facility, the passage comprising a linear drive mount, comprising the steps:
- a. extending a drive gear of the mobile robot from a first position spaced from the linear drive mount to a second position where the drive gear is engaged with the drive mount, the drive gear mounted to a shaft;
- b. rotating the shaft and drive gear by a motor, the motor having a first spline and the shaft having a second spline, the shaft rotating by a force exerted by the first spline on the second spline;
- and
- c. preventing improper seating of the drive gear against the linear drive mount by, at least in part, providing a degree of play between the first and second splines, the play allowing a degree of free rotation of the drive gear relative to the linear drive mount as the drive gear extends from the first position to the second position.
A method of transporting a mobile robot along a vertical or inclined passage between storage levels in an order fulfillment facility, the passage comprising a linear drive mount, comprising the steps:
- d. extending a drive gear of the mobile robot toward the linear drive mount until the drive gear initially engages the linear drive mount, the drive gear mounted to a shaft;
- e. retracting the shaft and drive gear away from the linear drive mount in the event of overlap or improper meshing of the drive gear with the linear drive mount;
- f. rotating the shaft and drive gear an amount less than the pitch between gear teeth on the drive gear in the event of overlap or improper meshing of the drive gear with the linear drive mount in said step (a);
- g. re-extending the drive gear and shaft toward the linear drive mount after said step (c) until the drive gear again engages the linear drive mount in the event of overlap or improper meshing of the drive gear with the linear drive mount in said step (a);
- and
- h. extending the drive gear into full meshing engagement with the linear drive mount in the event of proper meshing of the drive gear with the linear drive mount.
Dependencies are inferred from the claim text.