Abstract:
A surface vehicle capable of overcoming obstacles is disclosed in which the vehicle accelerates vertically while having a horizontal velocity. The vehicle has a frame and at least three wheels attached to the frame to which a horizontal propulsion system is coupled. Further, a vertical propulsion system is coupled to the frame and the wheels. The vertical propulsion system is capable of providing a force to such wheels normal to the surface so that the vehicle separates from the surface. The vehicle has an electronic control unit coupled to the vertical propulsion system to automatically control its operation.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a vehicle capable of overcoming obstacles such as fences, ledges, boulders, rivers, and ditches. In particular, the vehicle accelerates vertically while having a horizontal velocity.  
       BACKGROUND OF THE INVENTION  
       [0002]     A surface vehicle is a device that transports itself and a payload from place to place on the surface of the earth or other celestial body. Such vehicles can lose their mobility when encountering obstacles: positive obstacles which stick up from the average surface, such as logs, boulders, fences; negative obstacles such as holes, ledges, or ditches; and non-supportive surfaces such as rivers, ponds, or swamp muck. The inventors of the present invention have recognized that it would be desirable to have a surface vehicle which is not limited by such obstacles.  
         [0003]     Prior art vehicles, such as motorcycles, are capable of overcoming obstacles; however, they require a ramp to impart a vertical component of velocity. This is impractical for free roaming vehicles for which it is desirable to overcome any obstacle encountered regardless of the presence of a ramp.  
         [0004]     A prior art vehicle capable of imparting a vertical acceleration to the vehicle is a low rider, in which hydraulic cylinders are energized to cause the vehicle to rise and fall. There are several disadvantages of a low rider vehicle for the purpose of traversing an obstacle. Typically, not all wheels of the low rider leave the ground, or if they do, either the rear or front wheels leave the ground only a small distance. The low rider does not provide sufficient acceleration to cause the vehicle to leave the ground an appreciable distance with a single actuation of the hydraulic cylinders. Instead, the cylinders are bounced at a resonant frequency to cause the vehicle to attain a significant vertical height with multiple actuations of the hydraulic cylinders. Such operation does not allow a low rider vehicle to clear an obstacle. Additionally, the control of the hydraulic cylinders is controlled remotely by a human operator. Moreover, the low rider is not adapted to provide significant vertical acceleration when the vehicle is translating on the ground. Instead, the highest vertical heights are achieved when the vehicle is not translating. Yet another disadvantage for the low rider in overcoming a positive obstacle is that the wheels are actuated in a downward direction to cause the vehicle to accelerate upward. With the wheels at their lowest extent possible, they would be the limiting factor for such a vehicle in clearing a positive obstacle.  
         [0005]     Rockets and jet propulsion are used to generate vertical acceleration in known devices. However, both require a large amount of energy to provide the acceleration. Although they might be used to clear one or a few obstacles, they are impractical for clearing multiple obstacles that a vehicle might encounter simply because the fuel needs are too great.  
       SUMMARY OF THE INVENTION  
       [0006]     Disadvantages of prior art surface vehicles are overcome by a surface vehicle system having a frame, at least three members coupled to the frame, and a horizontal propulsion system coupled to the frame. The horizontal propulsion system provides motive force to at least one of the members to cause the vehicle to translate along the surface. The vehicle further includes a vertical propulsion system coupled to the frame and the members, which is capable of providing a force to the members generally normal to the surface to cause all members to lift off the surface. The vehicle includes an electronic control unit coupled to the vertical propulsion system to automatically control operation of the vertical propulsion system. In one embodiment, the members are wheels. In an alternative embodiment, the members are tracks.  
         [0007]     In one embodiment, the vertical propulsion system includes a hydraulic cylinder capable of developing a large, controlled vertical force between the members in contact with the ground and the body of the vehicle for sufficient time to accelerate the vehicle in a substantially vertical direction to launch it free of the surface. The vertical force is applied while the vehicle is at a controlled speed horizontally. Thereby, the vehicle can be propelled over an obstacle. The vertical force is sufficient to cause the vehicle to attain more than 1 g of acceleration such that it lifts from the surface. The term ‘g’ refers to the acceleration of gravity, which is 9.8 m/s 2  for earth. This gravitational constant is different for alternative celestial bodies.  
         [0008]     By being separated from contact with the surface to a significant height for a significant period of time during which it moves a controlled distance horizontally, the vehicle returns to the surface having traversed the obstacle. Since it does this without recourse to aerodynamic lift, yet another advantage of the present invention is that the vehicle doesn&#39;t need large surfaces that make the vehicle wide, or rocket propulsion that is too energy intensive to be practical for a vehicle without a long duration mission.  
         [0009]     Yet another advantage of the present invention is in evasive maneuvers. Should there be a moving obstacle, such as another vehicle in the vicinity that is out of control, the vehicle of the present invention can provide a higher acceleration rate vertically than the less than 1 g acceleration rate that can be generated horizontally. Thereby, a collision with an errant vehicle or other moving mass can be avoided by jumping upward.  
         [0010]     Another advantage of the present invention is that the vehicle can be accelerated vertically in a single actuation without the need for a ramp, as required by jumping cars or motorcycles, or an energy-intensive rocket propulsion device.  
         [0011]     A method is also disclosed for operating a vehicle in which a vertical propulsion device is actuated. The vertical propulsion device is coupled between a frame of the vehicle and members in contact with the ground. The actuation of the vertical propulsion device causes the members to apply a substantially normal force of sufficient magnitude to the surface that the resulting acceleration of the vehicle is greater than 1 g. The entire vehicle lifts off the ground by a single actuation of the vertical propulsion device. The method further includes retracting the wheels toward the frame after the members are no longer in contact with the ground, particularly in clearing a positive obstacle. Further, the members are extended away from the frame after the vehicle has cleared the positive obstacle and before the vehicle impacts the ground. In one alternative, the propulsion device is a hydraulic cylinder. A valve in the hydraulic cylinder is adjusted to provide damping as the vehicle impacts the surface. In another alternative, the vertical propulsion device is an internal combustion cylinder. Each member is equipped with a vertical propulsion device.  
         [0012]     In one embodiment, the members are wheels and the vehicle includes a horizontal propulsion device, which applies a torque to rotate at least one of the wheels to cause the vehicle to translate along the ground.  
         [0013]     The method also includes detecting an obstacle over which the vehicle cannot travel if it remains substantially in contact with the ground. In response to detecting the obstacle, a signal is provided to actuate the vertical propulsion device. The detection is inputted to and the actuating signal is provided by an onboard electronic controller electronically coupled to the vertical propulsion device. The horizontal propulsion device is also electronically coupled to the electronic control unit. The electronic controller commands the horizontal propulsion system to actuate the horizontal propulsion device to attain a predetermined translational velocity prior to actuating the vertical propulsion device so that the vehicle clears the obstacle. The obstacle is a positive obstacle, a negative obstacle, or a non-supportive surface.  
         [0014]     The method described in the present invention allows determination of whether the vehicle can clear the obstacle prior to actuating the vertical propulsion device, thereby mitigating a collision with the obstacle. If it is determined that the obstacle could be cleared if the vehicle had a higher translational velocity, the vehicle can approach the obstacle for a second time after having attained that higher velocity. If it is determined that the obstacle cannot be cleared, the vehicle is commanded to find a more favorable location. In one alternative, a test of surface condition is made to determine whether the surface is sufficiently stable to support the applied downward force of the members to accelerate the vehicle vertically. This is done by sensing the reaction of the vehicle and members to a known pulse of the vertical propulsion system.  
         [0015]     Other features and advantages of the present invention will be apparent from the accompanying drawings, and from the detailed description that follows below 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The invention will now be described further by way of example only and with reference to the accompanying drawings in which:  
         [0017]      FIG. 1  is an elevation schematic of a jumping vehicle according to an aspect of the present invention;  
         [0018]      FIG. 2  is a plan schematic of a jumping vehicle according to an aspect of the present invention in which an example of a horizontal propulsion system is shown;  
         [0019]      FIG. 3  is a plan schematic of a jumping vehicle according to an aspect of the present invention in which an example of a vertical propulsion system operated hydraulically is shown;  
         [0020]      FIG. 4  is an illustration of a first half of a jump sequence for a jumping vehicle in overcoming a positive obstacle;  
         [0021]      FIG. 5  is an illustration of a second half of a jump sequence for a jumping vehicle after overcoming a positive obstacle;  
         [0022]      FIG. 6  is a schematic of a jumping vehicle according to an aspect of the present invention; and  
         [0023]      FIG. 7  is a schematic of a plan view of the vehicle showing wheel base and track width. 
     
    
     DETAILED DESCRIPTION  
       [0024]     A vehicle according to the present invention is shown in  FIGS. 1 and 2 ,  FIG. 1  being an elevation view and  FIG. 2  being a plan view. The vehicle has a frame  10  to which three or more members are connected. In the present example, there are 4 members and the members are wheels  20 . The front wheels are connected to the frame by A-arms: the left front wheel via A-arm  40  and the right front wheel via A-arm  42  (shown in  FIG. 2  only). The left hand front wheel is slightly forward of the right hand left wheel to accommodate A-arms  42  being in a plane without contacting each other. Also, A-arm  42  connected to the right hand wheel angles toward the rear of the vehicle and A-arm  42  connected to the left hand wheel angles toward the front of the vehicle. The rear wheels are mounted on a solid axle  48  connected to frame  10  by radius arms  24  and lateral control link  22 . Steering of the front wheels is accomplished by linear actuators  50  mounted to A-arms  40 ,  42  and connected to steering knuckles  13 . Steering knuckles  13  are attached to the front knuckles on which wheel spindles are mounted. The vehicle is propelled horizontally, i.e., along the surface, by an engine  30 , which in one embodiment is an internal combustion engine, gasoline or diesel. Engine  30  is coupled to a motor generator  35  via a dog clutch  32 . The shaft from motor generator  35  is connected to a transmission  34  through a clutch  32 . Transmission  34  is connected to driveshaft  18  which connects to the differential  46  in rear axle  48  which drives the rear wheels  20 . The drivetrain shown in  FIGS. 1 and 2  is a hybrid configuration. In a non-hybrid embodiment, engine  30  connects to transmission  34  through clutch  32 . Both embodiments of the vehicle use a battery  24 . A higher capacity battery is used for the hybrid application. A battery for a non-hybrid version is sized to start engine  30  and to supply any onboard accessories.  
         [0025]     The horizontal propulsion system may be a steam engine, a Stirling cycle engine, a gas turbine engine, a reciprocating internal combustion engine, such as a gasoline engine (often referred to as Otto cycle), a diesel engine, and variants including: 2-stroke, 4-stroke, homogeneous charge compression ignition or any other known type.  
         [0026]     Referring now to  FIG. 3 , an embodiment of a hydraulic vertical propulsion system is shown. The hydraulic vertical propulsion system is also included in the vehicle shown in  FIGS. 1 and 2 . However, for the sake of simplicity, the mechanical and hydraulic systems are highlighted separately in the two views. The hydraulic system includes a hydraulic fluid reservoir  64  which supplies hydraulic fluid to hydraulic pump  66 . Hydraulic pump  66  is driven off engine  30 . In another embodiment, an electric motor is used to drive pump  66 . High pressure hydraulic fluid is supplied to accumulators, front  60  and rear  62 . In an alternate embodiment, a single accumulator could be used. The front accumulator  60  is connected to the front hydraulic control valve  68 ; similarly, accumulator  62  is connected to rear hydraulic control valve  70 . The hydraulic control valves supply hydraulic fluid to the vertical propulsion cylinders  38  or hydraulic struts. The lines between the hydraulic control valves and the vertical propulsion cylinders  38  connect to both ends of the vertical propulsion cylinders  38 : supplying fluid to one end of vertical propulsion cylinder  38  causes wheels  20  to extend from frame  10  and supplying fluid to the other end of vertical propulsion cylinder  38  causes wheels  20  to retract toward frame  10 . Hydraulic fluid return lines connect from vertical propulsion cylinders  38  to reservoir  64 .  
         [0027]     If the terrain over which vehicle  8  is traveling is uneven, it is desirable to have independent control of each wheel. As shown in  FIG. 3 , front wheels  20  have control valve  68  and rear wheels have control valve  70 , which can be independently controlled. In an alternate embodiment, vehicle  8  is equipped with a control valve for each wheel.  
         [0028]     Referring now to  FIGS. 4 and 5 , the phases of a jump over a positive obstacle are shown. Vehicle  8  is traveling normally in phase a, in which the suspension is not fully retracted to allow for ground clearance of the vehicle. Vehicle  8  translates along the surface at a forward velocity of 20 kilometers per hour (kph). In preparation for a jump, wheels  20  are retracted to cause vehicle  8  to hunker down toward ground  6 , as shown in phase b. The vertical propulsion system is actuated causing wheels  20  to exert a downward force toward ground  6  forcing wheels  20  to separate from frame  10 . In reaction, vehicle  8 , is accelerated vertically, and rises, shown as phase c. While wheels  20  are in contact with surface  6  as shown in phase c, they continue to exert a downward force. When vehicle  8  reaches the limit of the suspension travel, wheels  20  lift off the ground as they are carried up with vehicle  8 . Phase d shows a time after wheels  20  have come off ground  6  and remain extended. To clear obstacle  4 , wheels  20  are retracted toward vehicle  8 , as shown in phase  3 . Continuing with  FIG. 5 , after clearing obstacle  4 , wheels  20  can be extended from vehicle  8  to prepare for touchdown, as shown in phase f. At phase g, wheels  20  of vehicle  8  have contacted ground  6 . In phase h, the suspension has compressed to cushion the landing with ground  6 . In phase i, the suspension is extended to achieve its standard ground clearance.  
         [0029]     In the event that the obstacle being traversed is a negative obstacle, such as a chasm, or a neutral obstacle such as a ravine, vehicle  8  proceeds as shown in  FIGS. 4 and 5 , except that in step e, there is no need to retract the wheels. It is better not to retract the wheels to save the energy that would otherwise be expended in retracting and then later lowering the wheels in step f. In this case, the vehicle reaches the apogee of the jump at step e; however, the relative position of vehicle  8  and the wheels remains nearly constant through steps d through f.  
         [0030]     In  FIG. 6 , vehicle  8  is moving in the direction of obstacle  4 . Vehicle  8  is equipped with electronic control unit  62 , which is in communication with image capture unit  62  and sensors  64 . Images from unit  62  can be analyzed to determine that vehicle  8  is approaching an obstacle. Sensors  64  can include various sensors which can be used to infer the condition of surface  6 . Sensors  64  can act from a distance by measuring radiative properties of the surface, surface irregularities, as a couple of examples. Sensors  64  can have an extendable arm (not shown) which can be used to impact surface  6  to determine its ability to support members  20  in making a jump. In one embodiment, sensors  64  collect a small amount of soil from surface  6  and make an onboard determination of the properties of surface  6 .  
         [0031]     In  FIG. 7 , the wheel base and track width are shown in a plan view of vehicle  8 .  
         [0032]     Although not shown in the figures, electronic control unit  62 , or another electronic control unit similar to unit  62  is electronically coupled to both the vertical and horizontal propulsion systems to actuate hydraulic cylinders  38 , control arms  40  and  42 , and engine  30 . Electronic control unit obtains information from engine  30 , sensors  64  (providing, for example but not limited to, ambient condition signals, fuel signals, vehicle payload signals, vehicle condition signals such as relative position of frame  10  with respect to wheels  20 ) sensors associated with the vertical propulsion system, sensors associated with the steering mechanism, etc. From these signals, engine  30  controls the vertical propulsion system, the horizontal propulsion system, and the steering mechanism of vehicle  8  to allow it to traverse terrain which would otherwise be unattainable for vehicle  8 .  
         [0033]     While the present invention has been described, those skilled in the art will appreciate various changes in form and detail may be made without departing from the intended scope of the present invention as defined in the appended claims.