Body signal control device and related methods
A method for controlling a powered wheelchair is disclosed. The method may comprise receiving first information from at least one user sensor coupled to a user of the wheelchair, said first information indicating the movement of the user; receiving second information from a reference sensor coupled to the wheelchair, said second information indicating the movement of the wheelchair; using the first information and the second information to prepare at least one instruction to move the wheelchair; and using the at least one instruction to move the wheelchair.
1. A method for controlling a powered wheelchair, the method comprising:
providing a control module executed by a computing device, and a plurality of sensors in operative communication with the control module, the plurality of sensors including one or more user sensors coupled to shoulders of a user, and a reference sensor coupled to a powered wheelchair;
training the control module to interpret an intended movement of the powered wheelchair by the user, by:
(i) generating training information by recording, by the plurality of sensors, a first plurality of measures corresponding to a sequence of predetermined self selected and self paced shoulder motions comfortable to the user as based on residual mobility available to the user,
(ii) repeating step (i) to tailor the control module to a range of motion defined by the residual mobility of the user, and
(iii) preparing, by the control module, a weighing matrix from the training information that defines one or more values uniquely corresponding to the range of motion defined by the residual mobility of the user;
generating an instantaneous position matrix from a second plurality of measures recorded by the plurality of sensors as the user executes a movement constrained by the residual mobility; and
multiplying the weighing matrix by the instantaneous position matrix to derive a position matrix defining a control command from the user to move the powered wheelchair based on the movement of the user.
2. The method of claim 1 , further comprising, by the control module, converting the training information to the weighing matrix using orthogonal transformation, the weighing matrix representing a first component to control a translational movement of the powered wheelchair and a second component to control a rotational movement of the powered wheelchair.
3. The method of claim 1 , wherein the weighing matrix weighs values of an instantaneous position information using principal component analysis such that a first principal component accounts for as much variability in the training information from each signal of the one or more user sensors, and each succeeding component in turn has a highest variance possible under a constraint that it be orthogonal with preceding principal components.
4. The method of claim 3 , wherein the control module utilizes principal components to control the powered wheelchair in a supplementary mode.
5. The method of claim 3 , further comprising, by the control module, altering the weighing matrix to encourage the user to make movements for controlling the powered wheelchair to rehabilitate a predetermined body portion of the user.
6. The method of claim 1 , further comprising:
accessing reference frames associated with the plurality of sensors,
computing a rotation angle between any two of the reference frames using vectors a and b corresponding to roll and pitch respectively measured by the plurality of sensors, and
using the rotation angle to construct a rotation matrix to project measurements from the reference sensor into the reference frames of the one or more user sensors to align the reference frames of the plurality of sensors.
7. A device for customized control of a powered wheelchair, comprising:
a plurality of sensors including a user sensor positioned along a shoulder of a user, and a reference sensor positioned along a powered wheelchair; and
a computing device in operative communication with the plurality of sensors, the computing device executing a control module that adapts to a residual mobility of the user, such that the control module:
accesses training information associated with a first plurality of measures recorded by the plurality of sensors as the user conducts a sequence of predetermined self selected and self paced shoulder motions comfortable to the user as based on the residual mobility of the user,
generates a weighing matrix from the training information that defines one or more values uniquely corresponding to a range of motion defined by the residual mobility of the user,
accesses control information associated with a second plurality of measures recorded by the plurality of sensors as the user conducts a movement related to the sequence of predetermined self selected and self paced shoulder motions comfortable to the user as based on the residual mobility of the user; and
applying the weighing matrix to the control information to determine a control command to move the powered wheelchair.
8. The device of claim 7 , wherein the weighing matrix decreases dimensionality of a control space and adapts control of the powered wheelchair to the residual mobility of the user.