Brain-body actuated system

• US 5,692,517 A
• Filed: 12/08/1995
• Issued: 12/02/1997
• Est. Priority Date: 01/06/1993
• Status: Expired due to Fees

• Current Assignee: Andrew Junker
• Original Assignee: Andrew Junker
• Inventors: Junker, Andrew
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US08/569,671
• Time in Patent Office: 725 Days
• Field of Search: 128/731-733, 128/905, 434/236, 434/112, 434/323, 434/336, 434/350, 273/DIG. 28, 273/438, 345/156, 345/157, 341/20, 341/21, 341/34, 340/825.19, 340/825.24, 463/36
• US Class Current: 600/545
• CPC Class Codes: A61B 5/375 using biofeedback
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06F 3/015 Input arrangements based on nervous system activity detection, e.g. brain waves [EEG] detection, electromyograms [EMG] detection, electrodermal response detection
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: Y10S 128/905 Feedback to patient of biological signal other than brain electric signal

Abstract

A method and apparatus for assisting a user to control a device in response to a combination of electroencephalographic and electromyographic potentials. The user selects a number of reference frequencies in a range of from 0.5 Hz to 45 Hz defining a like number of control signals. A digital lock-in amplifier is used with a moving average time window filter to produce control signals which are presented to the user. Control system responsiveness is controlled by adjusting the lengths of the moving average time windows. A phase-locked loop is closed around each control signal and is used to track the shifting frequencies of the control signals. The user is able to sense and control changes in the magnitude and frequency of the control signals in the control of the device. By sensing the changes in the magnitude and frequency of the control signals, the user is able to learn a combination of mental and/or physical activities for which changes in the electroencephalographic and electromyographic biopotentials are correlated to control of the device.

Claims

1. A method of controlling a device in response to biopotentials produced by a user, the method comprising the steps of:

providing a control signal having a reference frequency;

detecting the biopotentials;

producing in response to detecting the biopotentials an input signal changing as a function of changes in the biopotentials;

sampling the input signal at successive sample times to produce sampled input signals over successive sample times; and

periodically computing X and Y quadrature values at the reference frequency of the control signal for the sampled input signals;

periodically computing averaged X and Y quadrature values by averaging the X and Y quadrature values for the sampled input signals with moving average time windows, said moving average time windows averaging the X and Y quadrature values over a selectable length of time adaptable to a user; and

periodically computing an averaged magnitude of the control signal in response to the averaged X and Y quadrature values, the averaged magnitude of the control signal being associated with the reference frequency and changing as a function of both changes in magnitude of the biopotentials and the selectable length of time;

presenting to the user a representation of the averaged magnitude of the control signal to enable the user to sense the changes of the magnitude of the biopotentials; and

controlling the device as a function of the changes of the magnitude of the biopotentials.

2. The method of claim 1 wherein the step of periodically computing averaged X and Y quadrature values further comprises the step of adjusting the selectable length of time of the moving time average windows, thereby adapting to the user a rate of change of the averaged X and Y quadrature values in response to changes in the biopotentials.

3. A method of controlling a device in response to biopotentials produced by a user, the method comprising the steps of:

providing a control signal having a reference frequency;

detecting the biopotentials;

producing in response to detecting the biopotentials an input signal changing as a function of changes in the biopotentials;

sampling the Input signal at successive sample times to produce sampled input signals over successive sample times; and

periodically computing X and Y quadrature values at the reference frequency of the control signal in response to the sampled input signals;

periodically computing over a user selectable length of time averaged X and Y quadrature values by averaging the X and Y quadrature values; and

periodically computing an averaged magnitude of the control signal in response to the averaged X and Y quadrature values, the averaged magnitude of the control signal being associated with the reference frequency and changing as a function of changes in magnitude of the biopotentials and the user selectable length of time;

presenting to the user a representation of the averaged magnitude of the control signal to enable the user to sense the changes of the magnitude of the biopotentials; and

controlling the device as a function of the changes of the magnitude of the biopotentials.

4. The method of claim 3 wherein the step of periodically computing averaged X and Y quadrature values further comprises the step of providing an input adaptable for use by the user to adjust the user selectable length of time, thereby adapting to the user a rate of change of the averaged X and Y quadrature values in response to changes in the biopotentials.

5. A method of controlling a device in response to biopotentials produced by a user, the method comprising the steps

providing a control signal having a reference frequency

detecting the biopotentials;

producing in response to detecting the biopotentials an input signal changing as a function of changes in the biopotentials;

sampling the input signal at successive sample times to produce sampled input signals over successive sample times; and

establishing a base phase value of the control signal at the reference frequency in response to one of the sampled input signals;

periodically computing time averaged phase values of the control signal in response to subsequent sampled input signals each of the time averaged phase values representing an average frequency of the biopotentials within a predetermined bandwidth of frequencies with respect to the reference frequency;

periodically comparing each of the time averaged phase values to the base phase values;

periodically changing the reference frequency as a function of comparing the time averaged phase values to the base phase values, the reference frequency changing as a function of changes of the average frequency of the biopotentials;

establishing a new base phase value of the control signal in response to the changing reference frequency;

presenting a representation of the changing reference frequency to the user to enable the user to sense the changes of the average frequency of the biopotentials; and

controlling the device as a function of the changes of the average frequency of the biopotentials.

6. A method of controlling a device in response to biopotentials produced by a user, the method comprising the steps of:

providing a control signal having a reference frequency

detecting the biopotentials;

producing in response to detecting the biopotentials an input signal changing as a function of changes in the biopotentials;

sampling the input signal at successive sample times to produce sampled input signals over successive sample times; and

periodically computing X and Y quadrature values at the reference frequency of the control signal for the sampled input signals;

periodically computing time averaged X and Y quadrature values by averaging the X and Y quadrature values for the sampled input signals in moving average time windows; and

periodically computing time averaged phase values in response to the time averaged X and Y quadrature values, each of the time averaged phase values of the control signal representing an average frequency of the biopotentials with respect to the reference frequency;

periodically changing the reference frequency as a function of the time averaged phase values of the control signal, the reference frequency changing as a function of changes of the average frequency of the biopotentials;

presenting representations of the changes ef the reference frequency to the user to enable the user to sense the changes of the average frequency of the biopotentials; and

controlling the device as a function of the changes of the average frequency of the biopotentials.

7. A method of presenting representations of biopotentials produced by a user, the method comprising the steps

providing a control signal having a reference frequency:

detecting the biopotentials;

producing in response to detecting the biopotentials an input signal changing as a function of changes in the biopotentials;

sampling the input signal at successive sample times to produce sampled input signals over successive sample times;

periodically computing magnitude and phase values at reference frequency of the control signal in response to the sampled input signals;

averaging over a selectable length of time adaptable to a user the magnitude and phase values to produce averaged magnitude and averaged phase values of the control signal changing in response to changes in magnitude and frequency of the biopotentials and the selectable length of time; and

producing representations to the user of changes of the averaged magnitude and averaged phase values of the control signal to enable the user to sense changes in the biopotentials.

8. An apparatus for controlling an external device in response to biopotentials produced by a user, the apparatus comprising:

a sensor adapted to be mounted on the user for producing an input signal in response to detecting the biopotentials produced by the user, the input signal changing as a function of changes in the biopotentials;

a digital signal processor operatively connected to the sensor and periodically sampling the input signal, the digital signal processor providing a control signal having a reference frequency and including a digital lock-in amplifier means for

periodically computing X and Y quadrature values at a reference frequency of the control signal in response to periodic samples of the input signal,

periodically computing over a selectable length of time adaptable to a user averaged X and Y quadrature values in response to the X and Y quadrature values with a digital moving average time window filter, and

periodically computing a magnitude value of the control signal at the reference frequency in response to the averaged X and Y quadrature values, the magnitude of the control signal changing as a function of changes in magnitude of both the biopotentials and the selectable length of time;

an output device connected to the signal processor and providing a representation to the user of the magnitude of the control signal to enable the user to sense changes in the magnitude of the control signal as a function of changes in the magnitude of the biopotentials; and

a controller operatively connected to the signal processor and the external device for controlling the external device as a function of changes in the magnitude of the biopotentials.

9. An apparatus for controlling an external device in response to biopotentials produced by a user, the apparatus comprising:

a sensor adapted to be mounted on the user for producing an input signal in response to detecting the biopotentials produced by the user, the input signal changing as a function of changes in the biopotentials;

a digital signal processor operatively connected to the sensor and periodically sampling the input signal, the digital signal processor providing a control signal having a reference frequency and including a digital lock-in amplifier means for

periodically computing X and Y quadrature values at the reference frequency of the control signal in response to periodic samples of the input signal,

periodically computing averaged X and Y quadrature values in response to the X and Y quadrature values, and

periodically computing a phase value of the control signal at the reference frequency in response to the averaged X and Y quadrature values, the phase value of the control signal changing as a function of changes in frequency of the biopotentials,

the digital signal processor further including a digital phase locked loop responsive to the phase value of the control signal for changing a frequency of the reference frequency as a function of a change of the phase value of the control signal;

an output device connected to the signal processor and providing representations of the frequency of the reference frequency to the user to enable the user to sense changes in the frequency of the reference frequency as a function of changes of the frequency of the biopotentials; and

a controller operatively connected to the signal processor and the external device for controlling the external device in response to the changes of the frequency of the biopotentials.

10. An apparatus for presenting representations of biopotentials produced by a user, the apparatus comprising:

a sensor adapted to be mounted at a single location on the user for producing an input signal in response to detecting the biopotentials produced by the user, the input signal changing as a function of changes in the biopotentials;

a digital signal processor operatively connected to the sensor and periodically sampling the input signal, the digital signal processor providing a control signal having a reference frequency and including a digital lock-in amplifier means for

periodically computing X and Y quadrature values at the reference frequency of the control signal in response to periodic samples of the input signals,

periodically computing over a user selectable length of time averaged X and Y quadrature values in response to the X and Y quadrature values with a digital moving average time window, and

periodically computing a magnitude value and a phase value of the control signal at the reference frequency in response to the averaged X and Y quadrature values, the magnitude and phase values of the control signal changing as a function of changes in magnitude and frequency of the biopotentials and the user selectable length of time, the digital signal processor further including a digital phase locked loop responsive to the phase value of the control signal for changing a frequency of the reference frequency as a function of a change of the phase value of the control signal; and

an output device connected to the signal processor for presenting representations of the magnitude of the control signal and the frequency of the reference frequency to the user to enable the user to sense changes in the magnitude and the frequency of the biopotentials.