Force actuated machine controller

• US 5,648,708 A
• Filed: 05/19/1995
• Issued: 07/15/1997
• Est. Priority Date: 05/19/1995
• Status: Expired due to Fees

• Current Assignee: Thelma F. Garin Trust
• Original Assignee: Power Concepts, Inc.
• Inventors: Littlejohn, Douglas J.
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US08/444,458
• Time in Patent Office: 788 Days
• Field of Search: 318/139, 318/481, 318/488, 318/489, 318/646, 318/648, 73/862.044, 73/862.042, 73/862.045, 74/471 XY, 180/907
• US Class Current: 318/488
• CPC Class Codes: G01L 5/161 using variations in ohmic resistance
• CPC Class Codes: Y10S 180/907 Motorized wheelchairs

Abstract

An apparatus and method that allows a user to exert a force to control a motive machine. The exerted force is transferred by a force transferring means to force sensors which detect the amount and direction in which the force is exerted. The force sensors convert the applied force into an electrical signal which is used to control the motive features of a machine.

Claims

1. An apparatus for controlling a direction and a speed in which a motive device propels a machine, said apparatus comprising:

(a) a plurality of force sensors for detecting a translational component of an applied force and for detecting a rotational component of said applied force;

(b) force transfer means formed of a rigid single moving part having a base surface coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors; and

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the machine in response to said detected translational component of said applied force and said detected rotational component of said applied force.

2. The force responsive apparatus of claim 1 wherein said force transfer means comprises a substantially half-spherical body.

3. An apparatus for controlling a direction and a speed in which a motive device propels a machine, said apparatus comprising:

(a) a plurality of force sensors for detecting a translational component of an applied force and for detecting a rotational component of said applied force;

(b) force transfer means, formed from a rigid substantially half spherical body coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors; and

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the machine in response to said detected translational component of said applied force and said detected rotational component of said applied force;

wherein said plurality of force sensors are evenly spaced around a perimeter of a ring concentric with the base of said substantially half spherical body.

4. An apparatus for controlling a direction and a speed in which a motive device propels a machine, said apparatus comprising:

(a) a plurality of force sensors for detecting a translational component of an applied force and for detecting a rotational component of said applied force;

(b) force transfer means, formed from a substantially half spherical body coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors, wherein said force transfer means further comprises a plurality of elastomeric bumpers, one for each of said plurality of force sensors, and wherein each of said elastomeric bumpers is positioned above its corresponding force sensor so that said applied force is transferred from said bumpers to said force sensors; and

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the machine in response to said detected translational component of said applied force and said detected rotational component of said applied force;

wherein said plurality of force sensors are evenly spaced around a perimeter of a ring concentric with the base of substantially half spherical body.

5. An apparatus for controlling a direction and a speed in which a motive device propels a machine, said apparatus comprising:

(a) a plurality of force sensors for detecting a translational component of an applied force and for detecting a rotational component of said applied force;

(b) force transfer means formed of a single moving part having a base surface coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors, wherein said force transfer means comprises;

an assembly member for receiving said applied force;

a support member for supporting said plurality of force sensors; and

a plurality of elastomeric bumpers for transferring said applied force from said assembly member to said force sensors; and

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the machine in response to said detected translational component of said applied force and said detected rotational component of said applied force.

6. The force responsive apparatus of claim 5 wherein said plurality of force sensors are supported by said support member at an angle of between 15 and 75 degrees to vertical.

7. The force responsive apparatus of claim 5 wherein said plurality of force sensors are supported by said support member at an angle of about 45 degrees to vertical.

8. The force responsive apparatus of claim 5 wherein:

said assembly member includes a plurality of cavities;

said force transfer means further comprises a plurality of spherical bearings which contact said plurality of elastomeric bumpers; and

each of said cavities is adopted to hold a portion of said spherical bearings such that a force applied to said assembly member is transferred to said spherical bearings, then to said elastomeric bumpers, then to said force sensors.

9. The force responsive apparatus of claim 8 wherein said force transfer means further comprises a plurality of washers with each washer being disposed between one of said elastomeric bumpers and one of said spherical bearings.

10. The force responsive apparatus of claim 8 wherein said assembly member includes a longitudinal bore through its center.

11. The force responsive apparatus of claim 5 wherein each of said force sensors is a force sensitive resistor.

12. The apparatus of claim 5 wherein said assembly member is substantially conical-shaped.

13. The force responsive apparatus of claim 12 wherein said plurality of force sensors are supported by said support member at an angle of between 15 and 75 degrees to vertical.

14. The force responsive apparatus of claim 12 wherein said plurality of force sensors are supported by said support member at an angle of about 45 degrees to vertical.

15. The force responsive apparatus of claim 12 wherein:

said assembly member includes a plurality of cavities;

said force transfer means further comprises a plurality of spherical bearings which contact said plurality of elastomeric bumpers; and

each of said cavities is adopted to hold a portion of said spherical bearings such that a force applied to said assembly member is transferred to said spherical bearings, then to said elastomeric bumpers, then to said force sensors.

16. The force responsive apparatus of claim 15 wherein said force transfer means further comprises a plurality of washers with each washer being disposed between one of said elastomeric bumpers and one of said spherical bearings.

17. An apparatus for controlling a direction and a speed in which a motive device propels a machine, said apparatus comprising:

(a) a plurality of force sensors for detecting a translational component of an applied force and for detecting s rotational component of said applied force;

(b) force transfer means formed of a single moving part having a base surface coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors;

wherein said plurality of force sensors comprises a first force sensitive ring resistor and a second force sensitive ring resistor; and

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the machine in response to said detected translational component of said applied force and said detected rotational component of said applied force.

18. An apparatus for controlling a direction and a speed in which a motive device propels a machine, said apparatus comprising:

(a) a plurality of force sensors for detecting a translational component of an applied force and for detecting a rotational component of said applied force;

(b) force transfer means formed of a single moving part having a base surface coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors;

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the machine in response to said detected translational component of said applied force and said detected rotational component of said applied force;

said motive control circuit comprising;

a filter for filtering out noise signals produced by said force sensors wherein said motive control circuit further comprises;

a deadband generator for reducing the effect a relatively small applied force has on the control of the motive device.

19. The apparatus according to claim 18 wherein said motive control circuit further comprises:

a scaling circuit that determines the sensitivity of response of direction and speed control of the motive device in relation to the applied force level.

20. The apparatus according to claim 19 wherein said motive control circuit further comprises:

a limiting circuit that limits the maximum translational velocity signal used to control the motive device.

21. The apparatus according to claim 20 wherein said motive control circuit further comprises:

a limiting circuit that limits the maximum rotational velocity signal used to control the motive device.

22. An apparatus for controlling a direction and a speed in which a motive device propels a machine, said apparatus comprising:

(a) a plurality of force sensors for detecting a translational component of an applied force and for detecting a rotational component of said applied force;

(b) force transfer means formed of a single moving part having a base surface coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors wherein said force transfer means comprises an assembly member for receiving said applied force from a user'"'"'s hand, a support member for supporting said plurality of force sensors, and a plurality of bumpers for transferring said applied force from said assembly member to said force sensors;

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the machine in response to said detected translational component of said applied force and said detected rotational component of said applied force; and

(d) a second plurality of force sensors for detecting a second applied force used to control an additional feature of said motive device wherein said second plurality of force sensors are positioned upon said assembly member to allow an additional axis-of-control to be controlled by one of said user'"'"'s fingers.

23. An apparatus for controlling a direction and a speed in which a motive device propels a wheelchair, said apparatus comprising:

(a) a plurality of force sensors for detecting first and second components of an applied force;

(b) a force transfer system formed from a single rigid moving part having a base surface coupled to said plurality of force sensors, for receiving said applied force and transferring said applied force to said plurality of force sensors; and

(c) a motive control circuit, coupled to said plurality of force sensors, for controlling the direction and the speed at which the motive device propels the wheelchair in response to said detected first and second components of said applied force.

24. A method of controlling speed and direction of a motive device, said method comprising the steps of:

(a) applying a force to an assembly member coupled to said motive device, said assembly member formed of a single rigid moving part having a base surface;

(b) transferring said applied force from said assembly member to a plurality of force sensors with a force transfer system, said plurality of force sensors positioned proximate said base surface;

(c) detecting a translational component and rotational component of said applied force with said force sensors and associated circuitry;

(d) translating, with a motive control circuit, the detected translational and rotational components of said applied force into signals to control said motive device.