BACKGROUND

The present disclosure relates to tools for verifying the path of a materials handling vehicle, and more particularly, to path validation tools for verifying the path of a materials handling vehicle in a warehouse. For the purposes of defining and describing the concepts and scope of the present disclosure, it is noted that a “warehouse” encompasses any indoor or otherwise covered facility in which materials handling vehicles transport goods including, but not limited to, warehouses intended primarily for the storage of goods, such as those where multi-level warehouse racks are arranged in aisles, and manufacturing facilities where goods are transported about the facility by materials handling vehicles for use in one or more manufacturing processes.

BRIEF SUMMARY

According to the subject matter of the present disclosure, a materials handling vehicle comprising a vehicle body, materials handling hardware, one or more wheels, a drive unit, a steering unit, a localization module, a navigation module, and a path validation tool. The drive unit, steering unit, localization module, and navigation module cooperate to direct the materials handling vehicle along a travel path in a warehouse. The path validation tool comprises environmental layout data of the warehouse, a proposed travel path within the warehouse, kinematics of the materials handling vehicle, and a dynamic vehicle boundary of the materials handling vehicle. The dynamic vehicle boundary of the materials handling vehicle approximates the physical periphery of the materials handling vehicle. The path validation tool executes path validation logic to (i) determine vehicle pose along the proposed travel path, (ii) update the dynamic vehicle boundary to account for changes in vehicle speed and steering angle, (iii) determine whether the dynamic vehicle boundary of the vehicle is likely to intersect obstacles represented in the environmental layout data based on the determined vehicle pose at candidate positions along the proposed travel path, (iv) determine a degree of potential impingement at the candidate positions by referring to the dynamic vehicle boundary of the materials handling vehicle and obstacle data represented in the environmental layout data, and (v) modify the proposed travel path to mitigate the degree of potential impingement. The drive unit, steering unit, localization module, and navigation module cooperate to direct the materials handling vehicle along the modified proposed travel path.

In embodiments, the dynamic vehicle boundary of the path validation tool comprises a dynamic exterior boundary of the materials handling vehicle and a dynamic clearance boundary of the materials handling vehicle, and the dynamic clearance boundary is enlarged relative to at least a portion of the dynamic exterior boundary of the materials handling vehicle to define an enlarged boundary about at least a portion of the materials handling vehicle. The path validation tool may execute path validation logic to (i) determine whether the dynamic clearance boundary of the materials handling vehicle is likely to intersect obstacles represented in the environmental layout data based on the determined vehicle pose at candidate positions along the proposed travel path, (ii) correlate likely points of intersection along the proposed travel path with vehicle pose at the candidate positions along the proposed travel path to build a list of potentially intersecting candidates along the proposed travel path, and (iii) determine the degree of potential impingement at the candidate positions by referring to the list of potentially intersecting candidates, the dynamic exterior boundary of the materials handling vehicle, and obstacle data represented in the environmental layout data. The path validation tool may execute path logic to determine vehicle pose along one of the proposed travel path and the modified proposed travel path at pre-determined intervals. The kinematics of the material handling vehicle may comprise at least a kinematic center C of the materials handling vehicle, data on the materials handling vehicle to include exterior dimensions, a turning radius, and pose data.

The materials handling vehicle may comprise a tugger and one or more trailers coupled to the tugger, and the pose data is indicative of pose data respectively of the tugger and the one or more trailers. The materials handling vehicle may comprise a tugger and one or more trailers coupled to the tugger, the dynamic vehicle boundary approximates a physical periphery of the tugger of the materials handling vehicle, and a potentially intersecting obstacle is a trailer of the one or more trailers coupled to the tugger. The materials handling vehicle may comprise a tugger and one or more trailers coupled to the tugger, the dynamic vehicle boundary approximates a physical periphery of a trailer of the one or more trailers of the materials handling vehicle, and a potentially intersecting obstacle is another trailer of the one or more trailers coupled to the trailer. The materials handling vehicle may comprise a tugger and one or more trailers coupled to the tugger, the dynamic vehicle boundary approximates a physical periphery of one of the tugger and the one or more trailers of the materials handling vehicle, and a potentially intersecting obstacle is an obstacle represented in the environmental layout data separate from the materials handling vehicle.

In further embodiments, the path validation tool executes path validation logic to (i) determine vehicle pose along the modified proposed travel path as the drive unit, steering unit, localization module, and navigation module cooperate to direct the materials handling vehicle along the modified proposed travel path, (ii) determine whether the dynamic vehicle boundary of the materials handling vehicle is likely to intersect obstacles represented in the environmental layout data based on the determined vehicle pose at candidate positions along the modified proposed travel path, (iii) determine a degree of potential impingement at the candidate positions by referring to the dynamic vehicle boundary of the materials handling vehicle and obstacle data represented in the environmental layout data, (iv) dynamically modify the modified proposed travel path to mitigate the degree of potential impingement and establish a dynamically modified travel path configured to merge from and to the modified proposed travel path, and (v) navigate the materials handling vehicle along the dynamically modified travel path. Establishment of the dynamically modified travel path configured to merge from and to the modified proposed travel path may comprise fitting a joining path to the modified proposed travel path, the joining path comprising a series of three clothoids and merge path lengths, the merge path lengths configured to be varied until a close fit comprising a lowest join error is determined. Optimization towards the lowest join error may comprise an initial proposed merge path comprising a 1:1:1 length ratio with respect to the ratios of clothoid lengths, the total length of the initial proposed merge path, and a curvature at an end of a first clothoid. The total length of the proposed merge path may comprise a Euclidean distance between a pair of join points. Curvature options with respect to the curvature may comprise an even spread between a maximum allowed positive curvature and a maximum negative path curvature, the even spread based on one or more steer angle limits.

In embodiments, the path validation tool executes path validation logic to identify the degree of potential impingement at the candidate positions as one or more problem areas of at least one of the proposed travel path and a configuration of the materials handling vehicle with respect to the proposed travel path. A degree of potential impingement may comprise an impingement distance that is an overlap distance at candidate positions indicative of an overlap between the dynamic vehicle boundary of the materials handling vehicle and obstacle data.

In accordance with one embodiment of the present disclosure, a materials handling vehicle comprising a vehicle body, materials handling hardware, one or more wheels, a drive unit, a steering unit, a localization module, a navigation module, and a path validation tool, wherein the drive unit, steering unit, localization module, and navigation module cooperate to direct the materials handling vehicle along a travel path in a warehouse. The path validation tool comprises environmental layout data of the warehouse, a proposed travel path within the warehouse, kinematics of the materials handling vehicle, a dynamic exterior boundary of the materials handling vehicle, and a dynamic clearance boundary of the materials handling vehicle. The dynamic exterior boundary of the materials handling vehicle approximates the physical periphery of the materials handling vehicle. The dynamic clearance boundary is enlarged relative to at least a portion of the dynamic exterior boundary of the materials handling vehicle to define an enlarged boundary about at least a portion of the materials handling vehicle. The path validation tool executes path validation logic to (i) determine vehicle pose along the proposed travel path, (ii) determine whether the dynamic clearance boundary of the materials handling vehicle is likely to intersect obstacles represented in the environmental layout data based on the determined vehicle pose at candidate positions along the proposed travel path, (iii) correlate likely points of intersection along the proposed travel path with vehicle pose at the candidate positions along the proposed travel path to build a list of potentially intersecting candidates along the proposed travel path, (iv) determine a degree of potential impingement at the candidate positions by referring to the list of potentially intersecting candidates, the dynamic exterior boundary of the materials handling vehicle, and obstacle data represented in the environmental layout data, and (v) modify the proposed travel path to mitigate the degree of potential impingement. The drive unit, steering unit, localization module, and navigation module cooperate to direct the materials handling vehicle along the modified proposed travel path.

In embodiments, the path validation tool executes path validation logic to update the dynamic exterior boundary and the dynamic clearance boundary to account for changes in vehicle speed and steering angle. A degree of potential impingement may comprise an impingement distance that is an overlap distance between a potentially intersecting candidate and the dynamic exterior boundary. The materials handling vehicle may comprise a tugger and one or more trailers coupled to the tugger, and the potentially intersecting candidate is one of the tugger, a trailer, and an obstacle represented by obstacle data in the environmental layout data. The potentially intersecting candidate may be a trailer, and the overlap distance is defined between the trailer and the dynamic exterior boundary of the tugger of the materials handling vehicle. The potentially intersecting candidate may be a trailer, and the overlap distance is defined between the trailer and the dynamic exterior boundary of another trailer of the one or more trailers of the materials handling vehicle. The potentially intersecting candidate may be the obstacle, and the overlap distance is defined between the obstacle and the dynamic exterior boundary of the materials handling vehicle.

In accordance with another embodiment of the present disclosure is a method of executing path validation logic with respect to a materials handling vehicle comprising a vehicle body, materials handling hardware, one or more wheels, a drive unit, a steering unit, a localization module, a navigation module, and a path validation tool, the drive unit, steering unit, localization module, and navigation module cooperate to direct the materials handling vehicle along a travel path in a warehouse, the method comprising receiving a plurality of inputs into the path validation tool, the plurality of inputs comprising environmental layout data of the warehouse, a proposed travel path within the warehouse, kinematics of the materials handling vehicle, and a dynamic vehicle boundary of the materials handling vehicle that approximates the physical periphery of the materials handling vehicle. The method further comprises determining vehicle pose along the proposed travel path through the path validation tool, updating the dynamic vehicle boundary to account for changes in vehicle speed and steering angle through the path validation tool, determining whether the dynamic vehicle boundary of the vehicle is likely to intersect obstacles represented in the environmental layout data based on the determined vehicle pose at candidate positions along the proposed travel path through the path validation tool, determining a degree of potential impingement at the candidate positions by referring to the dynamic vehicle boundary of the materials handling vehicle and obstacle data represented in the environmental layout data through the path validation tool, modifying the proposed travel path to mitigate the degree of potential impingement through the path validation tool, and navigating the materials handling vehicle along the modified proposed travel path through cooperation of the drive unit, steering unit, localization module, and navigation module.

In accordance with yet another embodiment of the present disclosure is a method of executing path validation logic with respect to a materials handling vehicle comprising a vehicle body, materials handling hardware, one or more wheels, a drive unit, a steering unit, a localization module, a navigation module, and a path validation tool, the drive unit, steering unit, localization module, and navigation module cooperate to direct the materials handling vehicle along a travel path in a warehouse, the method comprising receiving a plurality of inputs into the path validation tool, the plurality of inputs comprising environmental layout data of the warehouse, a proposed travel path within the warehouse, kinematics of the materials handling vehicle, a dynamic exterior boundary of the materials handling vehicle, and a dynamic clearance boundary of the materials handling vehicle. The dynamic exterior boundary of the materials handling vehicle approximates the physical periphery of the materials handling vehicle. The dynamic clearance boundary is enlarged relative to at least a portion of the dynamic exterior boundary of the materials handling vehicle to define an enlarged boundary about at least a portion of the materials handling vehicle. The method further comprises determining vehicle pose along the proposed travel path through the path validation tool, determining whether the dynamic clearance boundary of the materials handling vehicle is likely to intersect obstacles represented in the environmental layout data based on the determined vehicle pose at candidate positions along the proposed travel path through the path validation tool, correlating likely points of intersection along the proposed travel path with vehicle pose at the candidate positions along the proposed travel path to build a list of potentially intersecting candidates along the proposed travel path through the path validation tool, determining a degree of potential impingement at the candidate positions by referring to the list of potentially intersecting candidates, the dynamic exterior boundary of the materials handling vehicle, and obstacle data represented in the environmental layout data through the path validation tool, modifying the proposed travel path to mitigate the degree of potential impingement through the path validation tool, and navigating the materials handling vehicle along the modified proposed travel path through cooperation of the drive unit, steering unit, localization module, and navigation module.

