Omni-directional and holonomic rolling platform with decoupled rotational and translational degrees of freedom
First Claim
1. An apparatus for controlling a rolling platform having at least three wheel assemblies, each wheel assembly including a pair of ball wheels driven by a drive shaft of a corresponding drive motor, the apparatus comprising:
- means for inputting a command signal indicative of a desired platform direction and velocity of translation and angular velocity of rotation necessary to achieve a desired platform position and orientation following operation of the drive motors for a given period of time;
means for determining desired shaft velocities for the at least three drive motor shafts necessary to impart the inputted desired platform direction and velocity of translation and angular velocity of rotation;
first sensing means for sensing actual shaft velocity of the three drive motors;
second sensing means for sensing ground contact for the pair of ball wheels for each wheel assembly;
means, coupled to the first and second sensing means, for calculating actual platform position and orientation after a given time of operation of the drive motors;
means for comparing the desired platform position and orientation to the actual platform position and orientation; and
means for altering the command signal to achieve coincidence between the desired position and orientation of the platform and the actual position and orientation of the platform.
1 Assignment
0 Petitions
Accused Products
Abstract
A wheel assembly includes a support, a cage rotatably mounted on the support and having a longitudinal rotation axis, a first ball wheel rotatably mounted in the cage and having a rotation axis orthogonal to the rotation axis of the cage, and a second ball wheel rotatably mounted in the cage and having a rotation axis orthogonal to the rotation axis or the cage and to the rotation axis of the first ball wheel. A control circuit includes a photodetector signal which indicates ground contact for each ball wheel, and a tachometer which indicates actual drive shaft velocity.
-
Citations
23 Claims
-
1. An apparatus for controlling a rolling platform having at least three wheel assemblies, each wheel assembly including a pair of ball wheels driven by a drive shaft of a corresponding drive motor, the apparatus comprising:
-
means for inputting a command signal indicative of a desired platform direction and velocity of translation and angular velocity of rotation necessary to achieve a desired platform position and orientation following operation of the drive motors for a given period of time; means for determining desired shaft velocities for the at least three drive motor shafts necessary to impart the inputted desired platform direction and velocity of translation and angular velocity of rotation; first sensing means for sensing actual shaft velocity of the three drive motors; second sensing means for sensing ground contact for the pair of ball wheels for each wheel assembly; means, coupled to the first and second sensing means, for calculating actual platform position and orientation after a given time of operation of the drive motors; means for comparing the desired platform position and orientation to the actual platform position and orientation; and means for altering the command signal to achieve coincidence between the desired position and orientation of the platform and the actual position and orientation of the platform. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A rolling assembly comprising:
-
a platform having an upper surface and a lower surface; three ball wheel assemblies mounted on the lower surface of the platform, each having a pair of ball wheels operatively coupled to a drive motor; control means, coupled to the drive motors, for causing the drive motors to impart omni-directional, holonomic motion in the platform with fully decoupled and independently controllable translational and rotational movements, the motion of the platform being defined by three kinmatic equations having a plurality of directional variables; and movement command input means, for inputting at least three of the directional variable to thereby provide platform motion vectors based on the kinematic equations. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. An apparatus for controlling a rolling platform having at least three ball wheel assemblies, each assembly having two ball wheels driven by a drive shaft of a drive motor, the apparatus comprising:
-
means for outputting a drive signal indicative of a desired shaft velocity to each drive motor necessary to impart a desired motion in the platform; means for estimating the current orientation and position of the platform using data on the timing of contact with the ground switches from one wheel to the other for each wheel assembly; and means for correcting the drive signal to account for differences between the desired motion and the estimated current orientation and position of the platform. - View Dependent Claims (22, 23)
-
Specification