Reconfigurable footprint mechanism for omnidirectional vehicles
First Claim
1. A surface contacting wheel assembly, the assembly comprising:
- a support;
a plurality of members coupled to the support and characterized by a configuration, each member moveable about a common axis fixed with respect to the support and substantially perpendicular to the surface;
a plurality of wheels, each wheel coupled to one of the members, each wheel having a center of mass, each wheel having at least one point of contact with the surface, the points of contact of the plurality of wheels having a specified spatial relationship such that the specified spatial relationship is reconfigurable, before and during motion of the assembly; and
at least one sensor for measuring a physical quantity characterizing at least one of the configuration of the members, the motion of the wheel assembly, and the forces acting upon the wheel assembly.
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Accused Products
Abstract
A reconfigurable mechanism for varying the footprint of a wheeled omnidirectional vehicle. The variable footprint mechanism consists of a pair of beams intersecting at a pivotal point in the middle. Two pairs of ball wheels at the diagonal positions of the vehicle chassis are mounted, respectively, on the two beams intersecting in the middle. The angle between the two beams varies actively so that the ratio of the wheel base to the tread may change. Independent servomotors driving the ball wheels allow the vehicle to move in an arbitrary direction from an arbitrary configuration as well as to change the angle between the two beams and thereby change the footprint. By controlling the beam angle, static stability may be augmented, the width of the vehicle may be reduced, and the effective transmission ratio relating the vehicle speed to individual actuator speeds may be varied in a continuous manner.
212 Citations
27 Claims
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1. A surface contacting wheel assembly, the assembly comprising:
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a support; a plurality of members coupled to the support and characterized by a configuration, each member moveable about a common axis fixed with respect to the support and substantially perpendicular to the surface; a plurality of wheels, each wheel coupled to one of the members, each wheel having a center of mass, each wheel having at least one point of contact with the surface, the points of contact of the plurality of wheels having a specified spatial relationship such that the specified spatial relationship is reconfigurable, before and during motion of the assembly; and at least one sensor for measuring a physical quantity characterizing at least one of the configuration of the members, the motion of the wheel assembly, and the forces acting upon the wheel assembly. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A vehicle for locomotion over a surface under the control of a user, the vehicle comprising:
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a support; a plurality of members coupled to the support and characterized by a configuration, each member moveable about a common axis fixed with respect to the support and substantially perpendicular to the surface; a plurality of wheels, each wheel coupled to one of the members, each wheel having a center of mass, each wheel having at least one point of contact with the surface, the points of contact of the plurality of wheels having a specified spatial relationship such that the specified spatial relationship is reconfigurable, before and during motion of the assembly; and at least one sensor for measuring a physical quantity characterizing at least one of the configuration of the members, the motion of the wheel assembly, and the forces acting upon the wheel assembly; an input for receiving movement specification from a user; at least one wheel actuator for driving at least one of the plurality of wheels; and a processor for controlling the at least one actuator on the basis of the movement specification from the user and from the measured physical quantity. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of preventing a vehicle from tipping over while stationary, the vehicle having a support, a plurality of members, a plurality of moveable wheels and a controller, each wheel coupled to a member, each member moveable about a common axis with respect to the support, the method comprising the following steps:
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setting an initial vehicle footprint; applying a load to the vehicle; sensing instantaneous forces acting upon each of the plurality of wheels; calculating the mass centroid of the vehicle; moving the members about the common axis for reconfiguring the vehicle footprint such that a stability margin is optimized; and repeating the steps to account for time variable loads.
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26. A method of improving the maneuverability of a vehicle, the vehicle having a support, a plurality of members, a plurality of moveable wheels and a controller, each wheel coupled to a member, each member moveable about a common axis fixed with respect to the support, the method comprising the following steps:
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sensing a current vehicle footprint; calculating a new vehicle footprint; and moving the members about the common axis to reconfigure the current vehicle footprint to the new vehicle footprint.
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27. A method of improving the efficiency of a vehicle by changing the transmission ratio of the vehicle, the vehicle having a support, a plurality of members, a plurality of moveable wheels and a controller each wheel coupled to a member, each member moveable about a common axis fixed with respect to the support, the method comprising the following steps:
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sensing a current vehicle footprint; calculating a new vehicle footprint; and moving the members about the commons axis to reconfigure the current vehicle footprint to the new vehicle footprint.
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Specification