Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication
Reexamination Certificate
2003-04-21
2004-11-16
Nguyen, Thu V. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Reexamination Certificate
active
06819981
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to the field of power driven wheelchairs, in general, and more particularly, to a method and apparatus for setting speed/response performance parameters thereof to the operational capabilities of an individual user.
Power driven wheelchairs which may be of the type manufactured by Invacare Corporation of Elyria, Ohio, for example, generally include right and left side drive wheels driven by a motor controller via respectively corresponding right and left side drive motors, all of which being disposed on the wheelchair. An exemplary illustration of such a motor drive arrangement is shown in the schematic of FIG.
1
. Referring to
FIG. 1
, a motor drive controller
10
which may be an Invacare Mk VI™ controller, for example, controls drive motors
12
and
14
which are mechanically linked respectively to the right side and left side drive wheels of the wheelchair. A user interface
16
which may include a joystick
18
and selection switches (not shown) operable by a user is also disposed on the wheelchair in a convenient location to the user. The user interface
16
is generally interfaced to the controller
10
over a two wire serial coupling
20
to permit the user to select a drive program appropriate for operating the wheelchair in its environment and to adjust the direction and speed of the wheelchair within the selected drive program. The controller
10
may be programmed with a plurality of drive programs, each suited for a particular operating environment.
The motor controller
10
is generally powered by a battery source
22
, which may be 24 volts, for example, also disposed on the wheelchair. The drive motors
12
and
14
may be of the permanent magnet type and may be either a gearless, brushless AC motor or a brush type DC motor. The controller
10
may include a microcontroller interfaced and responsive to the user interface
16
to control drive signals
24
and
26
to motors
12
and
14
, respectively, via a power switching arrangement configured in accordance with the motor type being driven. The power switching arrangement may be powered by the 24V battery
22
. Thus, as the user adjusts the speed and direction of the wheelchair via the joystick of interface
16
, appropriate drive signals
24
and
26
are controlled by controller
10
to drive the motors
12
and
14
accordingly. Controller
10
generally controls motor speed to the user setting in a closed loop manner.
Actual speed of each motor
12
and
14
is derived from signals
28
and
30
respectively sensed therefrom. For example, for AC motors, a Hall Effect sensor may be disposed at the motor for sensing and generating a signal representative of angular position. The controller
10
may derive motor speed from a change in angular position for use as the actual speed feedback signal for the closed loop speed control of the motor. For DC motors, the voltage Va across the armature and armature current la may be sensed from each motor
12
and
14
and provided to the controller
10
via lines
28
and
30
, respectively. Controller
10
may in turn derive the actual speed of each motor
12
and
14
from the respective voltage Va and current la measurements thereof for use as the speed feedback signal for the respective closed loop speed control of each motor
12
and
14
.
For safety purposes, certain performance parameters of the wheelchair which may include, but not be limited to, forward speed, turning speed, reverse speed, response, forward acceleration, turning acceleration, turning deceleration, torque and braking (forward and reverse deceleration), for example, are preset during manufacture and stored in a non-volatile memory
32
, which may be an electrically erasable programmable read only memory (EEPROM), for example. The motor controller
10
is constrained in its control of the drive motors by these performance parameters. However, these factory preset performance parameters are established for an average user and are not meant to satisfy the safety needs and operating capabilities of all users. So, the wheelchair manufacturer stores the average performance parameters in a non-volatile memory which is alterable in the field, like the EEPROM.
When a power driven wheelchair is sold to a user at a dealership, for example, before the user may be allowed to operate the wheelchair unattended, a trained medical health adviser works with the user to determine safe performance parameters for the user based on the user's cognitive response and physical limitations, like tremors, arthritis, . . . etc. Currently, each of the aforementioned performance parameters is individually determined to satisfy each user's needs. Once determined, each of the new performance parameters is entered into the non-volatile memory
32
of the controller
10
through a remote programmer
34
which may be electrically coupled to a port of the microcontroller of controller
10
via signal lines
36
, for example, thus, rendering the wheelchair unique to the user's safe operating capabilities. Each dealer is generally provided with one or more remote programmers. Each remote programmer
34
may include a screen
38
for displaying interactive text and graphics and a plurality of pushbuttons
40
for communicating with the microcontroller which is programmed to interact with the programmer
34
and EEPROM
32
as will become more evident from the description found herein below.
Determining each safe performance parameter for a user may require an iterative procedure. That is, a user may first operate the wheelchair with a preset performance parameter, like forward speed, for example, under the observation of the medical adviser. If the user operation is found unacceptable, then a new parameter setting is entered into the controller via the programmer and the user operates the wheelchair with the newly entered parameter. From the observations, the medical adviser may readjust the parameter setting to better suit the user's operating capabilities and the procedure is repeated until the medical adviser is satisfied that the parameter setting is safely within the user's operational capabilities. This iterative procedure will continue individually for each performance parameter for a drive program and the process is repeated for each drive program of the controller.
Understandably, the determination of the individual performance parameters currently performed is a very timely and costly operation which needs improvement. The present invention is intended to address the timeliness and cost of the current parameter setting technique and provide a method and apparatus which overcomes the drawbacks thereof.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a method of setting values of a multiplicity of performance parameters of a power driven wheelchair into a controller thereof for use by the controller in the operation of the wheelchair by a user comprises the steps of: grouping the multiplicity of performance parameters of the wheelchair into at least two groups, each group including more than one performance parameter; for each group, (a) establishing a corresponding relationship between a selected performance parameter of the group and each of the other performance parameters of the group; and (b) presetting the established relationships into the controller of the wheelchair; determining a value for the selected performance parameter of each group based on the user's capabilities of operating the wheelchair; entering the determined value for the selected performance parameter of each group into the controller, deriving automatically by the controller for each group a value for each of the other performance parameters of the group based on the entered value of the selected performance parameter of the group and the corresponding established relationships of each of the other performance parameters with the selected performance parameter of the group; and storing the entered and derived values of the
Jacono Julie A.
Wakefield, II Theodore D.
Calfee Halter & Griswold LLP
Invacare Corporation
Nguyen Thu V.
Pejic Nenad
LandOfFree
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