Brain machine interface
Artificial control of a prosthetic device is provided. A brain machine interface contains a mapping of neural signals and corresponding intention estimating kinematics (e.g. positions and velocities) of a limb trajectory. The prosthetic device is controlled by the brain machine interface. During the control of the prosthetic device, a modified brain machine interface is developed by modifying the vectors of the velocities defined in the brain machine interface. The modified brain machine interface includes a new mapping of the neural signals and the intention estimating kinematics that can now be used to control the prosthetic device using recorded neural brain signals from a user of the prosthetic device. In one example, the intention estimating kinematics of the original and modified brain machine interface includes a Kalman filter modeling velocities as intentions and positions as feedback.
1. A method for artificial control of a prosthetic device, comprising:
a) storing a brain machine interface on a computer-readable medium and executable by a computer, wherein said brain machine interface comprises a mapping from neural signals to corresponding intention estimating kinematics of a limb trajectory, wherein said intention estimating kinematics comprises positions and velocities;
b) controlling said prosthetic device by said stored brain machine interface using recorded neural signals as input to said brain machine interface and said mapping of said brain machine interface to determine the intention estimating kinematics to control said prosthetic device, wherein said controlling results in an executed movement of said prosthetic device;
c) developing a modified brain machine interface by modifying and storing by said computer during said control of said prosthetic device, at discrete time intervals over the course of said executed movement of said prosthetic device, the vectors of said velocities in terms of direction as well as amplitude defined in said brain machine interface, wherein each of said modifications of said velocity vectors comprises changing the direction of said velocity vector towards an end target of said executed movement of said prosthetic device;
d) using said modified brain machine interface to control said prosthetic device; and
e) applying a kinematics feedback filter in both said brain machine interface and said modified brain machine interface, wherein said kinematics feedback filter applies a covariance matrix of an a posteriori estimate of said intention estimating kinematics at each time step of said discrete time intervals, whereby said positions are modeled as feedback from said interfaces to a user of said prosthetic device and said velocities are modeled as intentions of said user of said prosthetic device.
2. The method as set forth in claim 1 , wherein said modified brain machine interface comprises a new mapping of said neural signals and said intention estimating kinematics.
3. The method as set forth in claim 1 , wherein said a posteriori estimates of said positions in said covariance matrix are set to zero.
4. The method as set forth in claim 1 , wherein said prosthetic device is a robotic limb or a computer cursor.
5. The method as set forth in claim 1 , wherein said neural signals are signals from cortical neurons related to volitional tasks.