PROPORTIONAL AND NON PROPORTIONAL DRIVE CONTROL SYSTEM
A system and method for driving a power driven wheelchair is provided. One system embodiment may include, for example, a plurality of force sensing resistors, at least one force sensing resistor comprising a contactable surface for sensing a pressure thereon, wherein the at least one force sensing resistor generates a proportional signal in response to the sensed pressure. A controller comprising at least one input for receiving the proportional signal and having logic to receive the proportional signal and generate a control signal which is outputted to a motor controller to control the power driven wheelchair.
1 . A proportional input drive control device for a power driven wheelchair comprising:
a plurality of force sensing resistors, at least one force sensing resistor comprising a contactable surface for sensing a pressure thereon; wherein the at least one force sensing resistor generates a proportional signal in response to the sensed pressure; and
a controller comprising at least one input for receiving the proportional signal and having logic to:
determine a signal value from the proportional signal;
determine whether the signal value is above a threshold value;
determine a polarity of the signal value;
generate a control signal in proportion to the signal value if the signal value is above the threshold value; and
output the control signal to a motor controller for controlling the power driven wheelchair.
2 . The device of claim 1 further including:
a computer readable medium in operative communication with the controller, wherein the computer readable medium includes firmware.
3 . The device claim 1 wherein the plurality of force sensing resistors include four force sensing resistors, and wherein each of the four force sensing resistors includes a contactable surface, and wherein each of the four contactable surfaces includes a switch.
4 . The device of claim 3 wherein the four force sensing switches represent a forward direction, reverse direction, right direction and left direction respectively of the wheelchair.
5 . The device of claim 1 wherein the plurality of force sensing resistors include at least one contactable surface, wherein the at least one contactable surface includes at least one of a joystick and a micro joystick and a touch pad.
6 . The device of claim 1 wherein the plurality of force sensing resistors include at least one voltage divider, wherein the at least one voltage divider converts an incoming voltage signal from the contactable surface to the proportional signal.
7 . The device of claim 1 wherein the controller comprising at least one input for receiving the proportional signal further includes the proportional signal being transmitted to the controller, the controller determining the signal value based on the proportional signal.
8 . The device of claim 1 further including:
a reference voltage resistor, wherein the reference voltage resistor is in operative communication with the controller and wherein the reference voltage resistor generates a reference voltage which is transmitted to the controller.
9 . The device of claim 8 wherein the reference voltage establishes the threshold value and the controller compares the signal value to the threshold value.
10 . The device of claim 1 wherein the controller receives the proportional signal value in association with a particular input assignment to determine the polarity of the signal value.
11 . The device of claim 1 wherein the controller generates a control signal by adding the signal value to a neutral value.
12 . The device of claim 1 wherein the controller generates a control signal by subtracting the signal value from a neutral value.
13 . The device of claim 1 wherein the controller outputs the control signal to a motor controller, including transmitting at least one of a direction and turn signal components to the motor controller.
14 . A method of driving a power driven wheelchair comprising:
generating a proportional signal in response to a pressure applied to the surface area of at least one force sensing resistor;
determining a signal value associated with the proportional signal;
determining whether the signal value is above a threshold value;
determining a polarity of the signal value;
generating a control signal in proportion to the signal value if the signal value is above the threshold value; and
outputting the control signal to a motor controller for controlling the power driven wheelchair.
15 . The method of claim 14 wherein the step of generating a proportional signal in response to a pressure applied to the surface area of at least one force sensing resistor further comprises:
converting an incoming voltage signal to the proportional signal.
16 . The method of claim 15 wherein the converting step includes:
generating the proportional signal in proportion to the incoming voltage signal.
17 . The method of claim 14 wherein the step of determining a signal value associated with the proportional signal further comprises the step of transmitting the proportional signal to a controller.
18 . The method of claim 14 wherein the step of determining whether the signal value is above a threshold value further comprises a step of generating the threshold value by a reference voltage resistor.
19 . The method of claim 14 wherein the step of determining whether the signal value is above a threshold value further comprises a step of comparing the signal value to the threshold value.
20 . The method of claim 14 wherein the step of determining a polarity of the signal value includes receiving the proportional signal value in association with a particular input assignment of a controller.
21 . The method of claim 14 wherein the step of generating a control signal in proportion to the signal value further comprises the step of adding the signal value to a neutral value.
22 . The method of claim 14 wherein the step of generating a control signal in proportion to the signal value further comprises the step of subtracting the signal value from a neutral value.
23 . The method of claim 14 wherein the step of outputting the control signal to a motor controller includes transmitting at least one of a direction and turn signal components to the motor controller.
24 . A computer readable medium comprising logic to:
determine a signal value from the proportional signal;
determine whether the signal value is above a threshold value;
determine a polarity of the signal value;
generate a control signal in proportion to the signal value if the signal value is above the threshold value; and
output the control signal to a motor controller for controlling the power driven wheelchair.
25 . A method of driving a power driven wheelchair comprising:
generating a signal in response to a pressure applied to the surface area of at least one force sensing resistor;
determining a signal value associated with the signal;
determining whether the signal value is above a threshold value;
determining a polarity of the signal value;
generating a control signal if the signal value is above the threshold value; and
outputting the control signal to a motor controller for controlling the power driven wheelchair.
26 . The device claim 1 wherein the at least one force sensing resistor is configured to sense a pressure comprising a force in the range of less than 60 grams of force.