1. A robot capable of addressing various obstacles, comprising:
a chassis supporting a skid steered drive and having a leading end, a trailing end, and a chassis center of gravity (chassis CG) therebetween;
a set of driven flippers, each flipper having a pivot end, a distal end, and a flipper center of gravity (flipper CG) therebetween, each flipper being pivotable about a first pivot axis common with a drive axis near the leading end of the chassis;
a neck having a pivot end, a distal end, and a neck center of gravity (neck CG) therebetween, the neck pivotable about a second pivot axis substantially at the leading end of the chassis; and
a sensor head at the distal end of the neck, the head having a pivot end, a distal end, and a head center of gravity (head CG) therebetween, the head pivotable with respect to the neck about a third pivot axis at the distal end of the neck, the chassis, flippers, neck and head:
(i) having a combined center of gravity (combined CG) disposed in a fore-aft sense between the distal and pivot ends of the flippers when the flippers are in a stowed position with their distal ends between the leading and trailing ends of the chassis, and
(ii) being movable between a first position and a second position to overcome an obstacle; and
a programmed controller configured, by a plurality of executable instructions stored on the controller, to direct the robot to:
approach a plurality of stairs having a first pitch and a first step span;
raise the flippers to an angle of at least about 30 degrees;
mount a lowermost stair to a first position where the chassis is oriented at approximately the first pitch;
adjust flipper orientation to approximately match the first pitch; and
adjust the position of the overall gravitation center of the robot (robot CG) by moving the neck forward into a stair ascending position in which the head CG is forward of the chassis CG; and
climb the stairs by driving the flippers and the skid steered drive and maintaining the flipper orientation to approximately match the first pitch so that the robot spans at least two step edges.
2. The robot of claim 1, wherein the first position is a stair ascending position in which the head, neck, and flipper CGs are each forward of the leading end of the chassis such that the combined CG is forward of the chassis CG, and the second position is a stair descending position in which the head and neck CGs are disposed rearward of the leading end and the combined CG, such that the combined CG is rearward of the chassis CG.
3. The robot of claim 1 configured for climbing stairs having a pitch and step span, and wherein:
the chassis includes tracks defining a rearmost main track ground contact point;
each flipper includes a track defining a foremost flipper ground contact point;
the first position is a stable stair ascending position in which the head, neck, and flipper CGs are positioned to shift a vertical projection of the overall CG to at least one step span in front of the rearmost main track ground contact point and at least one step span behind the foremost flipper track ground contact point; and
the second position is an unstable stair ascending position in which the head, neck, and flipper CGs are positioned to shift a vertical projection of the overall CG to outside the stable range.
4. The robot of claim 1, wherein the first position is a crevasse approach position in which the head and neck CGs are aft of the leading end and aft of the combined CG, shifting the combined CG toward the trailing end, and the second position is a crevasse traversing position in which the head, neck, and flipper CGs are each fore of the leading end of the robot, shifting the combined CG toward the leading end.
5. The robot of claim 1, wherein the neck is adapted to carry payloads.
6. The robot of claim 1, wherein the flippers house at least part of a robot energy storage device and have a density higher than an average density of the robot.
7. The robot of claim 1, wherein the neck comprises at least one payload carrying fixture.
8. The robot of claim 1, further comprising a payload deck configured to support a removable cargo; and a linkage connecting the payload deck to the chassis, the linkage having a first end rotatably connected to the chassis at a first pivot, and a second end rotatably connected to the deck at a second pivot.
9. The robot of claim 1, wherein the flippers are operable to pivot about a front wheel drive axis of the chassis.
10. The robot of claim 1, wherein the sensor head comprises about 15 percent of a total weight of the robot.
11. The robot of claim 1, wherein the neck comprises about 5 percent of a total weight of the robot.
12. The robot of claim 1, wherein the set of flippers is constructed to have a lower density than that of the skid steered drive.
13. The robot of claim 1, further comprising a rear set of flippers.
14. A method of controlling a robot to climb stairs having a first pitch and a first step span, wherein the robot comprises:
a chassis supporting a skid steered drive and having a leading end, a trailing end, and a chassis center of gravity (chassis CG) therebetween;
a set of driven flippers, each flipper having a pivot end, a distal end, and a flipper center of gravity (flipper CG) therebetween, each flipper being pivotable about a first pivot axis common with a drive axis near the leading end of the chassis;
a neck having a pivot end, a distal end, and a neck center of gravity (neck CG) therebetween, the neck pivotable about a second pivot axis substantially at the leading end of the chassis; and
a sensor head at the distal end of the neck, the head having a pivot end, a distal end, and a head center of gravity (head CG) therebetween, the head pivotable with respect to the neck about a third pivot axis at the distal end of the neck,
the chassis, flippers, neck and head:
(i) having a combined center of gravity (combined CG) disposed in a fore-aft sense between the distal and pivot ends of the flippers when the flippers are in a stowed position with their distal ends between the leading and trailing ends of the chassis, and
(ii) being movable between a first position and a second position to overcome an obstacle;
the method comprising directing the robot to:
approach the stairs;
raise flippers to an angle of at least about 30 degrees;
mount a lowermost stair to a first position where the chassis is oriented at approximately the first pitch;
adjust flipper orientation to approximately match the first pitch;
adjust the position of the overall gravitation center of the robot (robot CG) by moving the neck forward into a stair ascending position in which the head CG is forward of the chassis CG; and
climb the stairs by driving the flippers and the skid steered drive and maintaining the flipper orientation to approximately match the first pitch so that the robot spans at least two step edges.
15. The method of claim 14, wherein the robot has a furthest rear main track ground contact and a front-most front ground contact; further comprising moving the neck and the head between a stair ascending position in which a vertical projection of the robot CG is located in a stable range at least one step span in front of the furthest rear main track ground contact and at least one step span behind the front most front track ground contact, and at least one alternate position in which the vertical projection of the robot CG is outside of the stable range.
16. A method of controlling a robot to overcome an obstacle, the method comprising directing the robot to perform the following tasks:
approach the obstacle;
raise flippers to an angle to mount the obstacle;
mount the obstacle to a first position where a robot chassis is oriented approximately at the first pitch;
adjust the flippers to shift a robot center of gravity at least laterally toward the obstacle; and
adjust a robot center of gravity (robot CG) by moving a neck forward into an obstacle mounting position.
17. The method of claim 16, wherein the adjusting the robot CG moves the robot CG downward.
18. The method of claim 16, wherein the robot comprises an articulated neck including a sensor head.
19. The method of claim 16, wherein the flippers house at least part of a robot energy storage device and have a density higher than an average density of the robot.
20. The method of claim 16, wherein the robot comprises an articulated neck further including payload-carrying fixtures.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A mechanical drive system for an accessory gearbox of a gas turbine engine, which engine has a high-pressure drive shaft and a low-pressure drive shaft, the drive system comprising:
a first tower shaft connected by a first gear arrangement to the high-pressure drive shaft;
a second tower shaft connected by a second gear arrangement to the low-pressure drive shaft, wherein the first tower shaft is concentric with the second tower shaft;
a first lay shaft connected by a third gear arrangement to the first tower shaft, and connected to the accessory gearbox, the third gear arrangement including a first bevel gear attached to the first tower shaft, and a second bevel gear attached to the first lay shaft, wherein the first bevel gear and the second bevel gear are engaged with one another;
a second lay shaft connected by a fourth gear arrangement to the second tower shaft, and connected to the accessory gearbox, wherein the first lay shaft is disposed spaced apart from and parallel to the second lay shaft;
wherein the fourth gear arrangement includes a first spur gear, a second spur gear, an intermediate shaft, a first bevel gear, and a second bevel gear, wherein the first spur gear is attached to the second tower shaft, and the second spur gear and the first bevel gear are attached to the intermediate shaft, and the second bevel gear is attached to the second lay shaft;
wherein the first spur gear and the second spur gear are engaged with one another; and
wherein the first bevel gear and the second bevel gear are engaged with one another.
2. A mechanical drive system for an accessory gearbox of a gas turbine engine, which engine has a high-pressure drive shaft and a low-pressure drive shaft, the drive system comprising:
a first tower shaft driven by the high-pressure drive shaft;
a second tower shaft driven by the low-pressure drive shaft;
a first lay shaft driven by the first tower shaft, and connected to the accessory gearbox; and
a second lay shaft driven by the second tower shaft, and connected to the accessory gearbox;
wherein the first lay shaft is disposed spaced apart from and parallel to the second lay shaft, and is connected to the second lay shaft by an intermediate shaft and a pair of spur gears wherein one spur gear is supported by the second tower shaft and the other spur gear is supported by the intermediate shaft.
3. The mechanical drive system of claim 2, wherein a first gear arrangement connects the first shaft to the first lay shaft, the first gear arrangement including a first bevel gear attached to the first tower shaft, and a second bevel gear attached to the first lay shaft, wherein the first bevel gear and the second bevel gear are engaged with one another.
4. The mechanical drive system of claim 2, wherein the first tower shaft and second tower shaft are concentric with one another.
5. A mechanical drive system for an accessory gearbox of a gas turbine engine, which engine has a high-pressure drive shaft and a low-pressure drive shaft, the drive system comprising:
a first tower shaft driven by the high-pressure drive shaft;
a second tower shaft driven by the low-pressure drive shaft;
a first lay shaft driven by the first tower shaft, and connected to the accessory gearbox; and
a second lay shaft driven by the second tower shaft, and connected to the accessory gearbox;
wherein the first lay shaft is disposed spaced apart from and parallel to the second lay shaft, and is connected to the second lay shaft by an intermediate shaft and gear arrangement.
6. A gas turbine engine, comprising:
a high-pressure drive shaft connected to a high-pressure compressor and a high-pressure turbine;
a low-pressure drive shaft connected to a low-pressure compressor and a low-pressure turbine;
wherein the high-pressure drive shaft and the low-pressure drive shaft rotate about an axially extending engine centerline;
an accessory gear box;
a first tower shaft driven by the high-pressure drive shaft, and connected to the accessory gearbox by a first lay shaft; and
a second tower shaft driven by the low-pressure drive shaft, and connected to the accessory gearbox by a second lay shaft, wherein the first tower shaft is concentric with the second tower shaft;
wherein the first lay shaft is disposed spaced apart from and parallel to the second lay shaft, and is connected to the second lay shaft by an intermediate shaft and a pair of spur gears wherein one spur gear is supported by the second tower shaft and the other spur gear is supported by the intermediate shaft.