BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of one aspect of the disclosed pedal feel emulating system;
FIG. 2 is a front elevational view of a second aspect of the disclosed pedal feel emulating system;
FIG. 3 is a sectional view, taken at line A-A of a pedal of the pedal feel emulating system of FIG. 1;
FIG. 4 is a top plan view of the section shown in FIG. 3; and
FIG. 5 is a graphical illustration of pedal travel versus pedal force of the pedal feel emulating system of FIG. 1.
DETAILED DESCRIPTION
As shown in FIG. 1, one aspect of the disclosed pedal feel emulating system, generally designated 10, may include a brake pedal 12, a mounting surface 14, an electronic control unit 16, a controllable electrical power source 18 and a force sensor 20. The mounting surface 14 may be positioned on the floor 15 of a vehicle (not shown) such that the pedal 12 extends upwardly from the floor 15. The brake pedal 12 may be a cantilevered brake pedal and may include a mounting portion 11 and an engaging portion 13. The mounting portion 11 of the pedal 12 may be securely connected to the mounting surface 14 by, for example, brackets, bolts, screws, adhesives, welding, rivets or any other available means. The engaging portion 13 of the pedal 12 may be adapted to be depressed by the foot 23 of a user 22.
Alternatively, in the system 10′ shown in FIG. 2, the mounting surface 14′ may be positioned above the floor 15′ of the vehicle such that the pedal 12′ is suspended from the mounting surface 14′ above the floor 15′.
Referring again to FIG. 1, the force sensor 20, which may be a strain gauge-type sensor, a piezoelectric-type sensor or the like, may be connected to the pedal 12 to sense a force supplied to the pedal 12 by the user 22. In one aspect, the force sensor 20 may be adapted to communicate a sensed force to the electronic control unit 16 by, for example, a communication line 24. Those skilled in the art will appreciate that communication line 24 may be a hard wired communication line or a wireless communication line.
Referring to FIGS. 3 and 4, the pedal 12 may be formed from, may include or may be a composite of piezoelectric material. As used herein piezoelectric material is intended to include any material capable of applying a force to a member when electrical power is supplied thereto. In one aspect, the pedal 12 may be formed from a plurality of piezoelectric fibers 30 suspended or dispersed in a carrier 32, such as a polymer matrix, wherein the piezoelectric fibers 30 are disposed between or connected to the two electrodes 34, 36.
Referring to FIGS. 1 and 3, the electrodes 34, 36 may be connected to the controllable electrical power source 18 by a supply line 38 and the controllable electrical power source 18 may in turn be connected to the electronic control unit 16 by a communication line 40 (FIG. 1). Alternatively, referring to FIG. 2, the electronic control unit 16′ may include an integral controllable electrical power source 18′ and the electrodes 34, 36 may be directly connected to the electronic control unit 16′ by a supply line 38′.
The piezoelectric fibers 30 may be woven or non-woven. In one aspect, the pedal 12 may be formed from a mesh of piezoelectric fibers 30 in a polymer matrix 32, wherein the mesh of piezoelectric fibers 30 is positioned between or connected to the electrodes 34, 36. Furthermore, the pedal 12 may include various reinforcing materials in or about the polymer matrix 32 to provide physical reinforcement to the pedal 12. For example, in addition to piezoelectric fibers 30, the pedal 12 may include fiberglass fibers, glass fibers, metal fibers and the like suspended in the polymer matrix 32.
Accordingly, when electrical power (e.g., a voltage) is supplied to the electrodes 34, 36, the piezoelectric fibers 30 positioned therebetween may be activated according to the well-known piezoelectric effect, thereby supplying a force to the polymer matrix surrounding the fibers 30 and effectively increasing the rigidity or stiffness of the pedal 12 (i.e., the willingness of the pedal 12 to flex when depressed). Therefore, the rigidity/stiffness of the pedal 12 may be controlled by controlling the amount of power supplied to the electrodes 34, 36 by the controllable electrical power source 18.
Thus, by controlling the rigidity/stiffness of the pedal 12 based upon signals received from the force sensor 20, the electronic control unit 16 may achieve a non-linear pedal travel versus pedal force, as shown in FIG. 5. For example, when the force sensor 20 detects a high force in the pedal 12, the electronic control unit 16 may direct the controllable electrical power source 18 to apply a higher voltage to the piezoelectric materials in the pedal, thereby increasing the rigidity/stiffness of the pedal 12 such that the user 22 experiences a greater resistance when depressing the pedal 12.
Although various aspects of the disclosed pedal feel emulator have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.
Patent Application
20070296268
