REFERENCE TO RELATED APPLICATION This application claims priority from U. S. Provisional Application Serial Number 60/444, 858, filed February 4,2003.

BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to steering assemblies and particularly to a module for a steering column assembly which provides tactile feedback to the operator.

Discussion of the Related Art Advances in technology have gradually resulted in the replacement of mechanical couplings with wire connectors and servos. The application of electronics to power steering assemblies for vehicles is disclosed in U. S. Patent No. 6,470, 995, which issued on October 29,2002. In that particular disclosure, the electronics assist the driver by relieving some of the stress of steering the vehicle by causing a driving force of an electric motor to directly act on a steering system. The disadvantage associated with this and other similar electronically aided steering systems is the operator does not receive tactile input through the steering assembly to provide a reaction as to how the vehicle is behaving. The tactile input, together with the optical input of the vehicle's behavior, provides the operator with a much keener sense of vehicle control. The present invention provides a straightforward inexpensive method and assembly for providing tactile feedback to the operator in a guide-by-wire steering system.

SUMMARY OF THE INVENTION The instant invention is directed towards an assembly for providing tactile feedback to the operator through the steering mechanism. The combination of characteristics of the various embodiments offers all the advantages of a mechanically coupled or direct connection steering column while at the same time overcoming the

disadvantages offered by the complicated mechanical connections. In addition, the instant invention offers safety advantages for the operator from impact with the steering mechanism during accidents.

According to one form of the invention, a steering column assembly for a vehicle is provided comprising a housing and a steering column shaft extending through the housing. A coil is fixed within the housing and is positioned adjacent at least a portion of the steering column shaft. The housing is filled with a fluid having a ferrous material in suspension which is reactive to a magnetic field or flux produced by the coil.

The strength of the field produced by the coil changes the particular viscous characteristic of the fluid which can be sensed by the vehicle operator to indicate the operator has reached the extent of the steering range, as well as detecting minor perturbations in terrain.

The invention described above further includes sensors remote from the housing for detecting a predetermined steering characteristic of the vehicle. A controller system is provided which is operably connected to the sensors and to the coil which determines the type of output signal to be passed to the coil for providing the appropriate signal to the operator.

It is contemplated the invention described herein could be an integral part of other steering components, including an encoder system for determining the rotation direction and ultimate magnitude of the input provided by the operator. This system could be formed as an integral part of the steering system or, alternatively, could be provided as a module. As a module, this application could be inserted as an after-market product with reasonable ease.

The advantages offered by the steering column assembly include increased flexibility in the location of the operator within the vehicle, improved safety for the operator of the vehicle from injuries produced by impact with the steering column assembly, engineering simplifications to the coupling and spacing arrangement for the steering column assembly as well as the flexibility in providing this as an integral or after-market optional package in a variety of steering systems.

These and other advantages of the steering column will become readily apparent once the reader refers to the detailed description of the invention below when taken in reference to the appended drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic illustration of a prior art mechanical steering system; Fig. 2 is a schematic illustration of a prior art wire steering system; Fig. 3 is a schematic diagram of one embodiment of the instant invention; Fig. 4 is a schematic illustration of one embodiment a tactile feedback module; and Fig. 5 is a schematic illustration of an alternate embodiment of a tactile feedback module.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT For purposes of the following description, the terms"upper,""lower," "left," "rear," "front," "vertical," "horizontal" and derivatives of such terms shall relate to the invention as oriented in each of the drawing pages. However, it is to be understood the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims.

Specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

According to one form of the invention shown in the drawing figures below, a steering assembly for a vehicle is provided, comprising a steering column housing; a steering column shaft mounted within the steering column housing; a feedback module within the steering column housing and extending around at least a portion of the steering column shaft; and a fluid within said feedback module containing magnetic particles.

The steering column assembly further comprising a sensor assembly operably coupled to the feedback module and provides an electrical signal to the feedback module resulting in altering a flow characteristic of the fluid. An encoder may also be provided and operably associated with the feedback module within the steering column housing for measuring a direction and angle of rotation of said steering column shaft.

The encoder in turn may be a separate or integral portion of the feedback module depending upon the needs of the user.

The steering column assembly also controls the steering of the vehicle via a motor operably interconnected to the feedback module (and encoder) and generates an output signal in response to a signal received from the feedback module, and more specifically the encoder. A gearbox assembly may be operably interconnected to the motor for moving at least one control surface or linkage arm in response to the output produced by the encoder associated with the feedback module. The exchange of signals between the feedback module and associated encoder and other devices is facilitated by a controller. The controller for example can provide an output signal corresponding to the angle of rotation of the steering column shaft as well as the magnitude of the rotation. The controller is also responsible for receiving the signals from the sensors and generating a signal back to the feedback module for providing the tactile signals to the operator. For example, in one instance, it is envisioned the sensors may be placed to detect the maximum rotation of wheels that steer a vehicle. Once that limit is reached, the sensors provide a signal to the controller that in turn generates a signal received by the feedback module. In response, the characteristic of the fluid is changed resulting in a locking of the steering column in that particular direction. In this configuration, the controller or similar functioning system is the link between the distant motor and sensor and the control in the hands of the user.

In another form of the invention, a steering assembly is provided, comprising a housing; a control extending at least partially through the housing; a feedback module disposed around at least a portion of the control; and at least one sensor operably interconnected to the feedback module for providing an input signal to the operator in response to external stimuli. The input signal to the operator produces a change in a handling characteristic of the control sensed by an operator. The change in the handling characteristic is manifested by a magneto-rheological fluid within the feedback module In addition, an encoder is provided that is adjacent the feedback module and provides an output indicative of rotation direction and vector of the control member. A motor assembly is remotely interconnected to encoder for producing a mechanical output in response to an input received from the encoder. In turn, the motor is controlled by a controller that receives the signal from the encoder.

The magneto-rheological fluid contained within the feedback module is of sufficient volume or quantity to at least partially surround at least a portion of the control member within the module. The module also includes an assembly proximate the portion of the control member for generating a magnetic flux in the magneto-rheological fluid about the control member. The magnetic flux or field alters the flow characteristic of the magneto-rheological fluid in response to the input signals received from at least one of the sensors.

The amount of friction or feedback applied to the steering assembly is in large part controlled by the amount of surface area of the steering assembly in contact with the magneto-rheological fluid. In one form a concentric disk is attached to a portion of the steering column shaft disposed within said housing or module. In this form, the assembly for generating the magnetic field is in the form of a coil having arms extending over opposite sides of the concentric disk. The amount of surface area affected by the magnetic field can be adjusted to accommodate the specific feedback characteristic.

In another form of the invention, a mechanism is provided for producing tactile feedback in a steer-by-wire or fly-by-wire guidance mechanism for a vehicle.

Such a system includes an operator-controlled input member used to provide the input signal for guiding the vehicle along a desired path selected by the operator. A module is attached to the operator-controlled input member for producing an output signal in response to the input, as well as a tactile input to the operator in response to an input signal-received from another location of the vehicle. The remote input may be produced by at least one sensor attached to a control surface or other portion of the vehicle. This sensor is preferably operably or electronically interconnected to the module for producing the input signal sensed by the operator.

The mechanism for producing the feedback to the operator is accomplished by a magneto-rheological fluid contained within the module and at least partially immersing a portion of operator-controlled input member. As mentioned above, the input signal from the remote sensor results in a magnetic field being produced in the fluid. The magnetic field in turn causes a physical change in the fluid that affects the ability of the fluid to flow or accept shear in one or more directions. This"binding"of the fluid inhibits functionality of said operator-controlled input member, producing a discernable or detectable change in the feel of the control.

The module generally described above may include a housing enclosing at least a portion of the operator-controlled input member as well as a volume of magneto- rheological fluid. A coil is located in close proximity to a portion of the operator- controlled input member and is preferably surrounded by the magneto-rheological fluid.

A remote controller electronically coupled to the coil and to the sensor determines how much of a magnetic field is produced by the coil to impart a force on the operator- controlled input member and detected by the operator. An encoder may also be coupled to the operator-controlled input member for detecting and outputting a signal indicative of a direction and magnitude of movement of the operator-controlled input member and outputting a respective signal to at least one of an actuator and a motor to move a control surface. At least one sensor is preferably coupled to the control surface or motor/actuator in a manner to detect a predetermined position of the control surface or motor and generate an output signal used by the controller.

The instant invention also provides a unique method for carrying out this procedure. According to one method, the invention provides tactile feedback to an operator of a control-by-wire system, including the steps of providing the operator with an operator-controlled input member to be touched by the operator; enclosing at least a portion of the operator-controlled input member in a module for producing a physical input to the operator-controlled input member in response to an input signal; providing at least one sensor attached to a control surface used to steer or guide the vehicle, and operably interconnecting the sensor to the module for transmitting the input signal to the module in response to the external stimuli detected by the sensor. The signal from the sensor then in turn is responsible for producing a magnetic field in a magneto-rheological fluid contained within the module. The magnetic fluid flow is altered by the magnetic field and thus inhibits the functionality of operator-controlled input member. The step of inhibiting functionality of the operator-controlled input member further comprises the step of changing the flow properties of said magneto-rheological fluid partially immersing the operator-controlled input member in response to the input signal received from one of the sensors.

The aspect of the method for changing the flow characteristics or properties of the magneto-rheological fluid includes generating a magnetic field within the magneto-rheological fluid immersing the operator-controlled input member and aligning a plurality of magnetic particles such as iron filings or other material suspended

within the magneto-rheological fluid. This aligning of the magnetic particles suspended within the magneto-rheological fluid changes the flow characteristic of the fluid by increasing the viscosity which in turn increases friction between the immersed components within the module.

The invention described herein is applicable to a wide range of mechanisms used to guide or otherwise steer a vehicle. Examples of such devices include steering wheels, steering columns themselves, joystick, yoke such as used in aircraft and the like, and levers used in armored vehicles such as armored personnel carriers, tanks, and the like.

Fig. 1 schematically illustrates a conventional mechanical steering column assembly 10 including a steering wheel 12 and at least one steering column shaft assembly 14 formed by a plurality of shaft sections 16 interconnected by universal joints 18. When combined, the steering column shaft assembly 14 interconnects steering wheel 12 to a steering gear box 20 or other mechanism responsible for actuating tie rods 22 to control the steering of the vehicle.

Fig. 2 illustrates a steer-by-wire arrangement 23 which substantially eliminates the mechanical connection provided by the steering column shaft assembly 14 shown in Fig. 1. In the embodiment shown in Fig. 2, a steering wheel 24 is coupled to one end of a shaft 26 terminating at the opposite end in a digital or analog encoder 28 for determining the direction and magnitude of the rotation of the steering column 24 by the operator. As schematically illustrated in Fig. 2, the output from the encoder 28 is then passed over a hard wire or optical fiber coupling 30 to a controller 32. The controller 32 interprets or decodes the signals generated by the encoder 28 and in turn generates an output which controls a motor having a shaft which is in turn coupled to the gear box 36.

The gear box 36 then translates the tie rods 38 the appropriate direction and distance to steer the vehicle.

The reader is directed to Figs. 3-7 which illustrate the various embodiments of the instant invention. Therein, Fig. 3 schematically illustrates a steering column assembly 40 for a vehicle, comprising in combination a steering wheel 42 coupled to one end of a steering column shaft 44 which extends through a housing 46. It is contemplated housing 46 can provide a physical means for attaching and mounting the steering column assembly 40 in a fixed or adjustable position within the vehicle. It is

further contemplated the steering column shaft may also be provided with bearings or journals at appropriate locations in order to support the steering column shaft 44 in housing 46. Examples of such housings are the subject of several United States patents owned by the assignee of this invention.

In the embodiment of the invention shown in Fig. 3, it is contemplated that steering column shaft 44 is not mechanically coupled to the gear box 48, but rather is coupled to a decoder/controller 52 electronically via a metal wire, optical fiber network, or rf or similar system generally indicated by reference numeral 50. In turn, decoder 52 activates a motor or actuator 54 mechanically coupled to the gear box 48. As in the previous embodiments, tie rods 56 are translated by the gear box 48 to control the steering direction of the vehicle.

Housing 46 receiving the steering column shaft 44 preferably includes a shaft encoder 58 for determining the rotation angle of the steering wheel 42 as well as a feedback module 60 for providing tactile input back through the steering column shaft 44 and steering wheel 42 to provide the operator with a better sense of control of the vehicle.

Although Fig. 3 illustrates the shaft encoder 58 and feedback module 60 as separate components, the functions of these two components may be combined into a single unit.

Shaft encoders identified by the numeral 58 are commercially available and will not be described in any great detail herein.

Fig. 4 schematically illustrates one embodiment of a feedback module which may be a standalone unit within housing 46 or incorporated as an integral portion of the shaft encoder 58 briefly mentioned above. As illustrated in the figure, the steering column shaft 44 extends through housing 46 and as well as through feedback module 60.

Feedback module 60 may be enclosed separately within its own housing 62 and be provided with seals 64 to encircle steering column shaft 44 and provide a liquid seal about the circumference of the shaft 44. Contained within the module housing 62 is a semicircular annulus shaped coil 64 having an inner radius 68 of slightly larger dimension than the radius of the steering column shaft 44. Coil 68 is placed in spaced relationship to the steering column shaft 44 so as to be concentric with the longitudinal axis of the shaft 44. Disposed between the inner radius 68 of the coil 66 and the circumference of the steering column shaft 44 is a very rigid, porous and permeable media which is securely bonded to the inside radius 68 of the coil 66 and extends within a predetermined distance

of the outer circumference of the steering column shaft 44, the purpose of which shall become apparent below. The outside radius 70 of the coil 66 extends into, and is rigidly secured within, a non-ferrous insulated mounting member 72 for securely fixing the coil 66 in spaced relationship with respect to the steering column 44. Wire leads, which are indicated as 74, are anticipated to extend through the mounting member 72 and through a seal (not shown) formed in the module housing 62. The seals for the wire leads and the shaft seal 64 are preferably sufficient to retain a magneto rheological fluid within the module housing 62.

Fig. 5 schematically illustrates the second embodiment of the feedback module 76 which may be formed as a standalone unit or incorporated as an integral portion of the shaft encoder 58 contained within the housing 46 described above. As shown in Fig. 5, the steel column shaft 44 extends through housing 46 as well as through feedback module 76. Module 76 may be enclosed separately within its own housing as indicated by dotted line 78 and be provided with seals such as 80 to encircle steering column shaft 44 and provide a liquid seal about the circumference of the shaft 44.

Disposed in module housing 78 and concentric with steering column shaft 44 is a disk 82 of predetermined diameter. It is contemplated that the diameter of the disk may range from as little as three-quarters of an inch greater than the diameter of the disk up to several inches in diameter which will proportionally change the amount of feedback detected by the operator. At the time of writing this application, it is further contemplated the disk is formed from a metallic material and is rigidly fixed to steering column shaft 44. However, it is further contemplated that the disk 82 may be formed from other materials and may even have opposing textured surfaces 84,86 for reasons that become apparent below.

Located at the peripheral edge of the disk 82, and preferably having portions which overlie and are adjacent to surfaces 849 869 is a C-shaped coil assembly 88, the arms of which, 90 and 92, extend a predetermined distance inwardly toward steering column shaft 44 and lie proximate surfaces 84, 86, respectively. The inwardly facing surfaces 94,96 of arms 90 and 92, respectively, and end wall 98 are bonded to a rigid, porous, and permeable media 100, the opposing boundaries of which extend within a predetermined distance of the surfaces 84,86 of the disk 82. The coil assembly 88 is maintained in a spatial relationship with respect to disk 82 by a non-conductive mounting

bracket assembly 102 to the module housing 78 such that coil assembly 88 remains stationary as the disk 82 moves through the C-shaped opening formed by arms 90 and 92 and end wall 98. In a preferred embodiment of the invention, the entire interior of the module housing 78 is filled with a magneto rheological fluid 104. However, it is further contemplated the coil assembly may be located in the lower half of the housing such that the housing only need to be partially filled with the magneto rheological fluid 104 so as to submerse the coil assembly therein Referring again to Fig. 3, the invention may essentially function with the operator steering the vehicle using steering wheel 42 which in turn rotates steering column shaft 44. As mentioned above, steering column shaft 44 is journaled to encoder 58 which contains electronics for determining the rotation angle as well as the incremental angular rotation which provides an output over lines 50 to controller 52. The controller 52 then in turn issues an output signal over line 110 to motor/actuator 54. The signal provided over line 110 to the motor/actuator 54 is preferably a DC signal which can cause the motor 54 to spin in one of two directions. The output shaft from the motor 112 is connected to the gear box 48 and depending upon the rotation direction of the motor, causes the tie rods 56 to move in unison in one of two directions.

The translation of the tie rods 56 may be monitored by an array of sensors generally designated by reference numerals 114 to continually provide output signals via lines 116 to the controller 52. In addition, or alternative thereto, sensors within the motor 44 or upon output shaft 112 may provide an output signal along line 116A to the controller to also indicate the linear travel of the tie rods 56. Regardless of the input and the source of that input, the controller then determines the output to the operator. For example, when the maximum turning angle of the steering mechanism has been reached, as the tie rods begin to reach the maximum range, the array of sensors 114 provides an output to the controller which then in turn provides an output over line 50 to the feedback module 60. The amplitude of the signal output from controller 52 is sensed by the feedback module 60 which then generates a field around the coil and within the magneto rheological fluid to produce friction upon the steering column shaft as the operator continues to turn in a particular direction. This way, the operator can then feel whether he or she has approached or has reached the maximum extent of the available turning angle.

In addition to the instant invention providing tactile feedback to the operator as to the extent of a particular turn, this invention also can provide real time tactile input indicating the reaction of the steering system to bumps, dips, and other mechanical responses by changing the degree of the amplitude of the signals to the feedback module. For example, small spikes in the amplitude or chirps can be sent to the feedback module in response to periodic perturbations in the signals being detected by the sensors 114. Another example is if there is a physical barrier preventing the steering device of the vehicle from moving, sensors detecting the pressure increase in the gear box or torque exerted by the motor may produce a signal which causes the field to increase and thus create substantial force on the steering column to indicate that the operator is receiving no reaction from the steering system.

In this fashion, the operator may be placed a significant distance from the actual mechanical structures responsible for steering the vehicle, thus eliminating the need for complex mechanical linkages from the steering wheel to the ultimate structure responsible for steering the vehicle as well as the need to remove mechanical boosting and power steering mechanisms. In short, this substantially reduces the mechanical engineering of the vehicle and reduces substantial danger to the operator often associated with the rigidly mounted steering columns. Indeed, the conventional steering column may be replaced by a gimbaled joystick wherein the gimbals could be mounted to pots which receive the output signal from the controller and provide the tactile feedback much as described in the conventional rotary steering wheel system described above.

These and other advantages of the steering column will become readily apparent once the reader refers to the detailed description of the invention below when taken in reference to the appended drawing figures.

The above description is considered that of the preferred embodiments only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.