CROSS REFERENCE TO RELATED APPLICATION

[00011 This application claims priority to U.S. Provisional Application No. 61/084,411 which was filed on July 29, 2008.

BACKGROUND

100021 This disclosure generally relates to a vehicle stability control system for a ground traveling vehicle. More particularly, this disclosure relates to an alternate system for slowing a vehicle.

[00031 Conventional braking systems control rotation of the vehicle wheels. Some braking systems pulsate hydraulic actuators to prevent a vehicle's wheel from locking up, and thereby provide better vehicle control in adverse conditions. Such anti- locking systems provide increased levels of safety and vehicle control, but are still limited by traction conditions existing between a vehicle's tires and a road surface.

[00041 Accordingly, it is desirable to design and develop an alternate braking system that does not rely on traction between a vehicle's tires and a road surface.

SUMMARY [00051 An exemplary device for stabilizing a vehicle and supplementing the vehicle braking system includes actuators that are extendable to engage a path surface separately from wheels of the vehicle. Contact between the actuators and the path surface creates frictional contact independent of the wheels that are selectively controlled to supplement vehicle stability and control. (00061 During normal operation, the actuators are stored in a retracted position and are not engaged with a path surface. When engaged, the actuators are separately extended into contact with the road surface. Frictional contact with road surface induces an additional drag that slows and stabilizes the vehicle. The drag on the vehicle is varied and adjusted as required by varying the amount of force exerted by each actuator. [00071 Control and selective actuation of the actuators in conjunction with disengaging the drive system of the vehicle supplements conventional vehicle control systems in order to maintain and regain control of vehicle movement lost due a loss of traction between the vehicle wheels and the road surface.

[00081 The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

100091 Figure 1 is a front view of a vehicle including an example vehicle stability control system. [000101 Figure 2 is a perspective view of a vehicle including the example vehicle stability control system

(000111 Figure 3 is a side view of a portion of the example vehicle stability control system

[000121 Figure 4 is a side view of a portion of the example vehicle stability control system in an engaged condition.

[000131 Figure 5 is rear view of the example vehicle stability control system.

[000141 Figure 6 is a bottom view of the example vehicle stability control system.

[000151 Figure 7 is a schematic view of an example stabilization system installed within a train carriage in a retracted position. [000161 Figure 8 is a schematic view of the example stabilization system installed within a train carriage in an extended position

[000171 Figure 9 is a block diagram illustrating the operational steps performed by the example braking and control system.

DETAILED DESCRIPTION

[000181 Referring to Figures 1 and 2, a vehicle 10 includes tires 12 and actuators 14, 16. The actuators 14, 16 are extendable from a bottom of the vehicle 10 to engage a road surface separately from the tires 12. Contact between the actuators 14, 16 and the road surface provides frictional contact independent of the tires 12 that is selectively controlled to supplement vehicle stability and control. Note that the term road surface us used throughout this application and is intended to include any path surface on which a vehicle may travel, including paved surfaces, railroad rails, dirt roads or any other surface comprising a path on which a vehicle may travel. The actuators 14, 16 also supplement the conventional wheel braking system by generating additional braking forces for stopping and controlling the vehicle 10. [000191 During normal operation, the actuators 14, 16 are stored in a retracted position and are not engaged with a road surface. When engaged, the actuators 14, 16 are separately extended from the bottom of the vehicle 10 and contact the road surface. The example actuators 14, 16 are shown on a bottom surface of the vehicle 10, however, the actuators may be mounted in any location of the vehicle determined to provide the desired contact with the road or ground surface.

[000201 Frictional contact with road surface induces an additional drag that slows and stabilizes the vehicle. The drag on the vehicle is varied and adjusted as required by varying the amount of force exerted by each actuator. 14, 16. The actuators 14 and 16 can be actuated with a force capable of lifting the vehicle wheels 12 off the roadway, thereby significantly increasing friction and drag to correct vehicle orientation.

[000211 Control and selective actuation of the actuators 14, 16 in conjunction with disengaging the drive system of the vehicle supplements conventional vehicle control systems in order to maintain and regain control of vehicle movement lost due a loss of traction between the vehicle wheels and the road surface. 1000221 Referring to Figures 3 and 4, a linear variable displacement transducer 38

(LVDT) is utilized to provide information indicative of the actuator 14, 16 extension from the vehicle in order to determine and obtain feed back of actuator 14, 16 position and contact with the road surface. The LVDT sensor 38 provides information indicative of a length in which the actuator is extended from a bottom of the vehicle 10. Although the example system utilizes an LVDT sensor 38, other position feed back sensors that provide information indicative of actuator position relative to the vehicle and the ground surface are within the scope and contemplation of this invention.

(000231 The stability control system 18 includes at least one actuator 14, 16. The disclosed example includes two actuators 14, 16 disposed proximate the vehicle drive wheels. However, it is within the contemplation of this invention that more actuators could be utilized and positioned anywhere within the vehicle based on application specific performance requirements.

1000241 The example actuators 14, 16, include a cylinder 20 and a head 22. The example cylinder 20 can be pneumatically, mechanically, electrically or hydraulically operated. The cylinder 22 is of sufficient size and capacity to create sufficient friction to change orientation or direction of the vehicle through the generation of drag forces on the vehicle. The head 22 is comprised of a material that produces a desired frictional contact with the roadway and that maintains the shape at speed. The example head 22 is semi- spherically shaped to provide for unidirectional contact. In other words, the shape of the example head 22 provides for actuation and uniform contact with the road surface regardless of a direction of movement of the vehicle 10. Accordingly, the head 22 can be of any shape that provides for uniform contact with the road surface regardless of the direction of movement of the vehicle 10. The shape can also be modified to take advantage of the angle of attach between the actuator and the road surface to create the desired friction and thereby drag on the vehicle to modify and stabilize vehicle trajectory.

1000251 Referring to Figures 5 and 6, the example system 18 utilizes information from wheel speed sensors 24 and motion detection sensors 26 installed within the vehicle

10. The example motion detection sensors 26 comprise accelerometers that provide an indication of a direction of motion of the vehicle 10. Information from the sensors 24, 26 is communicated to a controller 28. The controller 28 utilizes the information from the sensors 24, 26, to determine vehicle conditions, such as for example wheel spinning or lateral movement of the vehicle. Although, a wheel speed sensor and a motion detection sensor is disclosed, other sensors as are known can be utilized and are within the contemplation of this invention. The system utilizes this information, along with other available information relating to vehicle direction, speed and traction to determine what course of action is required to correct and/or maintain vehicle orientation.

[000261 The position information of the vehicle is utilized to recognize a condition where the vehicle has encountered a loss of desired stability such that appropriate action and actuation of the actuators 14, 16 is desired to regain stability of the vehicle. 1000271 Additionally, an elevation or height sensor 25 can be utilized for monitoring a distance between a bottom of the vehicle and the roadway. The height sensor can provide real time information on the relationship between the roadway and the vehicle. This information is also communicated to the controller 28 such that uneven pavement, surface conditions and other roadway inconsistencies can be accommodated and factored into actuation of the actuators. (000281 One or both of the actuators 14, 16 are actuated depending on the movement of the vehicle 10 and the required corrective action needed to regain, or maintain control of the vehicle 10. In some instances, the actuators 14, 16 may only momentarily contact the roadway to correct vehicle movement. In other instances, both actuators may fully engage the roadway as shown at 30, and thereby regain control of the vehicle.

[000291 The example controller 28 can include a global positioning system transmitter/receiver (GPS receiver) 32 to provide an indication of vehicle position. The GPS receiver 32 can be utilized along with known locations of roads and other locations to provide an indication of the need for a correction by engaging one or both of a predetermined number of the actuators 14, 16. The GPS receiver 32 provides information indicative of a vehicle position, such on which road the vehicle is traveling. Excessive speeds indicative of a loss of traction can be detected by the GPS receiver 32 and communicated to the controller 28 to facilitate and necessary actions. Further, the vehicle position detected by the GPS receiver 32 can indicate that the vehicle has left a roadway and communicate that information to the controller 28 such that necessary accommodations can be determined and implemented. For example, if the vehicle 10 has left a paved roadway and entered a dirt or gravel road, the controller 28 can take the difference in road surface into account should the actuators 14, 16 be required for actuation in maintaining or regaining vehicle stability. 1000301 The controller 28 includes a momentum controller receiver/transmitter 34 that utilizes information gathered from the plurality of sensors 24, 26, and the GPS receiver 32 to detect current vehicle momentum and determine if action is required to maintain and correct vehicle orientation and trajectory. The momentum controller 34 compares current vehicle orientation, speed, along with wheel speed and any other relevant information gathered by the vehicle sensors to determine if a loss of stability is occurring. [000311 If a loss of stability is detected or determined based on information received from the various sensors, that information is utilized to determine if corrective action is required. In the event that corrective action is required, the controller 28 will initiate actuation of the actuators 14, 16 to generate drag on the vehicle 10 to slow and stabilize the vehicle 10.

[OOO32I Referring to Figure 7, an example braking system 50 for a train traveling along a rail is schematically shown and includes actuators 58. The actuators 58 include pads 60 for engaging and generating frictional drag on the rail 52. The frictional drag created by the pads 60 generates significant frictional forces to increase braking force for the train. The braking system 50 is supported on a carriage 56 that also supports wheels 54. The wheels 54 provide only a very small contact surface for the generation of braking forces to slow and stop a train. The example system 50 includes pads 60 with a much larger contact area as compared to the contact area provided by the wheels. The larger contact area of the pads 60 greatly increases the surface area utilized for generating the frictional drag forces required to slow and stop the train.

[000331 The example actuators 58 are pneumatically operated and receive air from a pressurized air supply 64 already commonly used for actuating brakes that engaged the wheels 54 or axles supporting the wheels 54. The air supply 64 is thereby available and communicated to the actuators 58. A controller 62 controls actuation of the actuators 58 by operating corresponding proportional valve, schematically shown as 66. The controller 58 can thereby vary pressure within the actuators 58, which in turn controls the amount of frictional forces generated.

(000341 The pressurized air can be diverted entirely from the conventional braking system through actuation of the valve 66 when a circumstance arises requiring additional braking forces. Additionally, the stability control system 50 can be actuated in addition to a conventional braking system such that both the conventional and stability control system 50 is supplying braking forces.

[000351 The material utilized for the pads 60 is of material determined to generate the desired frictional forces under defined pressures exerted by the actuators 58. The cylinders of the actuators are sized such that pressures and forces as are desired can be exerted to generate the desired levels of friction and thereby braking forces. [000361 Referring to Figure 8, the actuators 58 are illustrated in an engaged position with the pads 60 forced against the rail 52. The pressure exerted by the actuators 58 is of a magnitude determined to create much larger frictional forces than are capable using only the relatively small contact area of the wheels 54. [000371 The stability control system 50 is utilized only for isolated urgent braking conditions such that pads 60 have a relatively long life span. Further, as the braking system 50 can provide additional braking forces, the wheels 54 are not damaged in urgent stopping conditions.

[000381 Referring to Figure 9, operation of the example system 18 for a motor vehicle is illustrated in flow diagram 70. Operation includes monitoring of vehicle operating conditions with the GPS receiver, and various vehicle sensors including speed, and position to determine momentum and proximity to other objects as indicated at 72.

Upon detection of the application of brakes as indicated at 74, when and if the momentum and other data, along with the application of the brakes are within predefined criteria the transmission is disengaged as indicated at 76. The predefined criteria of the vehicle is a circumstance where the data gathered from the various sensors is indicative of a condition such as slipping, spinning, or any other condition where normal braking is not sufficient to return a vehicle to a desired path.

I00039I The transmission is disengaged in response to the recognition of a defined condition to prevent the drive system from countering the correcting efforts of the system

18. A crash avoidance sensor provides information to the controller 28 indicative of whether or not the vehicle is in a condition proximate to another object as is indicated at

78. The controller 28 utilizes this information to determine if a potential collision or out of control system exists. If no collision condition exists, than the transmission and drive system is engaged and normal braking provides for the desired control of the vehicle as is indicated at 80.

[000401 If the controller 28 determines that the data received is indicative of potential collision conditions than the system 18 is engaged. An initial step is conducted utilizing the available sensors and data to determine current vehicle momentum, direction and trajectory as indicated at 82. The speed and direction includes movements of the vehicle in the pitch, yaw, and roll axes as indicated at 84. Further, information received from the crash avoidance sensor 78 is used to determine if an impact condition exists as indicated at 84. The knowledge of vehicle dynamics is utilized to determine which combination of the actuators 14, 16 are required to correct vehicle movement and regain control as indicated at 86. [000411 The controller 28 actuates one or both of the actuators 14, 16 that in turn extend from the bottom of the vehicle to contact the road surface. Contact with the road surface significantly increases drag and friction to slow the vehicle and provide an operator to regain control.

(000421 Once a desired vehicle trajectory and speed are reached, the actuators 14, and 16 are retracted and normal braking operations will resume as indicated at 88. If the vehicle continues in an undesired trajectory, the drive wheels, or any of the vehicle wheels can be lifted clear of the roadway until the vehicle comes to a complete stop as indicated at 90.

[000431 Accordingly, the example stability control system 18 provides actuators to slow, and stop a vehicle independent of any braking system that applies a braking force to slow the wheels. The example actuators contact the road surface to independently provide an alternate point of contact other than the vehicle wheels that in turn allows for regaining of vehicle control.

[00044] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.