Omnidirectional vehicle with offset wheel pairs

• US 6,540,039 B1
• Filed: 08/03/2000
• Issued: 04/01/2003
• Est. Priority Date: 08/19/1999
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Dubowsky, Steven, Yu, Haoyong
• Primary Examiner(s): LERNER, AVRAHAM H
• Application Number:
  US09/631,842
• Time in Patent Office: 971 Days
• Field of Search: 180/65.5, 180/253, 180/252, 180/264, 180/265, 180/263, 180/236, 180/237, 180/266, 180/267, 280/124.114, 16/47, 16/48, 16/29
• US Class Current: 180/253
• CPC Class Codes: B60B 33/0002 assembling to the object, e.g. furniture
• CPC Class Codes: B60B 33/0042 Double or twin wheels
• CPC Class Codes: B60B 33/0049 the rolling axle being horizontal
• CPC Class Codes: B60B 33/0057 the rolling axle being offset from swivel axis
• CPC Class Codes: B60B 33/0068 the swivel axis being vertical
• CPC Class Codes: B60B 33/0073 the swivel axis being symmetrical to wheel or wheels
• CPC Class Codes: B60K 17/043 Transmission unit disposed in on near the vehicle wheel, or between the differential gear unit and the wheel
• CPC Class Codes: B60K 17/30 the ultimate propulsive elements, e.g. ground wheels, being steerable
• CPC Class Codes: B60K 2007/0038 the motor moving together with the wheel axle
• CPC Class Codes: B60K 2007/0046 the motor moving together with the vehicle body, i.e. moving independently from the wheel axle
• CPC Class Codes: B60K 2007/0092 the motor axle being coaxial to the wheel axle
• CPC Class Codes: B60K 7/0007 the motor being electric
• CPC Class Codes: B62D 11/20 Endless-track steering having pivoted bogie carrying track B62D11/02 takes precedence
• CPC Class Codes: B62D 61/10 with more than four wheels tractors of the low ground pressure type B62D49/002

Abstract

A wheel base or mobile platform providing omnidirectional motion and control. At least two offset wheel assemblies are coupled to a platform that supports a load. Each offset wheel assembly has two wheels that share a common axis and a mechanical link that is pivotally coupled to a pivot point on the rigid platform and supports the two wheels in such a manner that the common axis is displaced from the pivot point. The common axis of the wheels is free to rotate about an axis parallel to the planes of rotation of the wheels. The platform may be turned in any direction specified by a user from any instantaneous configuration or velocity in accordance with a method uniquely specifying a torque to be applied to each of the wheels while each of the wheels is in rolling motion.

Claims

1. A mobile base for providing omnidirectional maneuverability, the mobile base comprising:

a. a rigid platform;

b. at least two offset wheel assemblies, each offset wheel assembly comprising;

i. two wheels having axles aligned along a common axis, the axles being free to rotate about an axis parallel to the planes of rotation of the wheels,

ii. a mechanical link pivotally coupled to a pivot point on the rigid platform and supporting the two wheels in such a manner that the common axis is displaced from the pivot point, and

iii. a rotary actuator for independently driving each wheel; and

c. a processor in communication with the rotary actuator for transforming a specified platform velocity vector to obtain a unique rotational velocity for each of the wheels.

2. A mobile base in accordance with claim 1, wherein the common axis of the two wheels of each offset wheel assembly is substantially perpendicular to a line connecting the midpoint between centers of the wheels to the pivot point.

3. A mobile base in accordance with claim 1, wherein the rotary actuator includes at least one motor.

4. A mobile base in accordance with claim 1, further including an input device for steering the mobile base in a specified direction.

5. A mobile base in accordance with claim 1, further including at least one sensor for sensing a velocity of a wheel.

6. A mobile base in accordance with claim 1, further including a control loop for correcting deviations of the mobile base from a specified velocity vector.

7. A mobile base in accordance with claim 1, further including at least one passive wheel for supporting the platform.

8. An omnidirectional vehicle comprising:

a. a support for supporting a load;

b. at least two offset wheel assemblies, each offset wheel assembly comprising;

i. two wheels having axles aligned along a common axis, the axles being free to rotate about an axis parallel to the planes of rotation of the wheels,

ii. a mechanical link pivotally coupled to a pivot point on the support and supporting the two wheels in such a manner that the common axis is displaced from the pivot point, and

iii. a rotary actuator for independently driving each wheel; and

c. a processor in communication with the rotary actuator for transforming a specified platform velocity vector to obtain a unique rotational velocity for each of the wheels.