Abstract:
A system for controlling rolling of a vehicle and a method therefor, the system comprising: a control unit for receiving and analyzing a steering signal and a driving signal from a driver of a vehicle having a frame by which the gradient of the vehicle during traveling can be controlled and generating a steering control signal and a driving control signal on the basis of a result value according to the analysis; and a steering unit and a driving unit for controlling a traveling direction and driving of the vehicle according to the steering control signal and the driving control signal received from the control unit, respectively.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to a system for controlling the rolling of a vehicle and a method therefor which are able to control the steering of a vehicle in such a way to adjust the inclination of the vehicle, and in particular to a system for controlling the rolling of a vehicle and a method therefor wherein the steering of the vehicle can be controlled in such a way that a sill connection plate is provided to connect left and right side sills of the vehicle, by which a wheel and a frame can be inclined in a desired direction during the change of the direction of the vehicle, thus controlling the steering of the vehicle, and a driving motor is provided at each wheel of the vehicle to control the speed of each driving motor, thus controlling the steering of the vehicle. 
         [0002]    The necessity on the development of an environmentally friendly future type vehicle or a predetermined transportation means is currently on the rise together with the increasing demand for an enhanced driver&#39;s driving convenience and safety. In order to satisfy these needs, a finished vehicle maker and a vehicle component maker are developing related technologies. 
         [0003]    In the sector of a vehicle chassis system (a driving, a steering, a suspension, a braking system, etc.), various researches and developments are underway as the performance of each electronic part and a chassis control technology advance more and more. In order to enhance the driving performance of a vehicle, each device and control system are being developed to cooperate each other, not simply combined. 
         [0004]    The rolling system is a system which would be applied to an environmental friendly future type vehicle or a predetermined transportation means and in general is formed of a driving motor which is provided at each wheel of the vehicle, a wheel and a frame which are configured to incline based on the change of the driving direction, and a combination of a steering part and a driving part. 
         [0005]    The driving direction change of the conventional vehicle can be carried out by rotating leftward or rightward a steering link provided to connect a front axle and a wheel of the vehicle in the direction which is horizontal to the ground. The above described conventional steering method has a problem wherein a centripetal force occurring during the turning of the vehicle may has bad effect on the riding comfort of a driver and passenger, and since the surface of each tire continuously contacts with the ground, and the tires may wear out a lot due to the frictions, thus degrading the durability of the vehicle. According to the conventional technology, since the direction change of the vehicle should be carried out only by rotating the steering link which is connected to the axle, it is impossible to carry out direction changes in response to different variables when the vehicle is driven on the corners. 
         [0006]    The Korean Patent Registration Number 0241375 (hereinafter referred to “a prior art”) describes the device for compensating the left and right leanings of the vehicle. More specifically, the above-mentioned prior art describes the device for compensating the left and right leanings of the vehicle in such a way that a vehicle speed, a steering angle, a lateral direction inclination of a road and a weight on each wheel are detected during the driving direction changes of the vehicle, and the lateral inclinations of the vehicle can be previously controlled, thus previously minimizing the lateral force that the driver and passenger may feel. 
         [0007]    The above described prior art, however, describes that the inclinations of the vehicle can be maintained by simply outputting a compensation signal to an actuator, namely, it does not specifically describe any method to control the inclinations of the vehicle and does not suggest any resolution to other matters related to the durability degradation due to the friction of the tires and the controls during the direction changes of the vehicle. 
         [0008]    For this reason, it needs to urgently develop a new vehicle rolling system which is able to resolve the above listed problems. 
         [0009]    The present invention has been invented based on the above-mentioned technology background. The present invention is able to satisfy the above mentioned technical needs and provide additional technical components that a person having ordinary skill in the art cannot easily invent. 
         [0010]    The present invention has been invented during the procedure to satisfy any technical needs to the vehicle chassis system, and an applicable range thereof is not limited to the vehicle chassis system. In other words, the present invention may be adapted or applied various transportation fields within a range covering the technical concepts which will be described below. 
         [0011]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY OF THE DISCLOSURE 
       [0012]    The present invention has been made in an effort to solve the above-described problems associated with prior art. 
         [0013]    An object of the present invention is to provide a system for controlling the steering of a vehicle in such a way that a frame is provided, which includes a sill connection plate and a sill connection shaft which connect left and right side sills of a vehicle, and the wheels connected to the front and rear axles of the vehicle and the frame are inclined leftward or rightward of the direction vertical to the ground during the rotation of the sill connection shaft, thus controlling the steering of the vehicle. 
         [0014]    Another object of the present invention is to provide a system which is able to simultaneously control a vehicle to turn in the horizontal direction with respect to the ground and the inclination of a vehicle body in the vertical direction with respect to the ground when changing the driving direction of the vehicle in such a way to provide a steering link which can be rotated leftward or rightward in the horizontal direction with respect to the ground. 
         [0015]    Further another object of the present invention is to provide a system for controlling the steering of a vehicle by controlling the speed of a driving motor in such a way to provide a driving motor and an electronic transmission to each wheel of the vehicle. 
         [0016]    Still further another object of the present invention is to provide a system which is able to maintain a stable driving of a vehicle with the aid of a steering control and a driving control in such a way to detect a vehicle state information using a sensor unit and calculate a compensation value with respect to the detected vehicle state information. 
         [0017]    Meanwhile, the technical resolutions of the present invention are not limited to the above-mentioned technical resolutions, and various technical resolutions may be further provided within a range wherein a person having ordinary skill in the art can draw from the descriptions of the present invention. 
         [0018]    The present invention provides as a means for resolving the above problems a system and method for controlling the rolling of a vehicle, and it is noted that the categories of these inventions are not limited to the expressions used herein the specification, but can be interpreted into various meanings within the scope of the present invention. 
         [0019]    Accordingly, in one aspect, the present invention provides a system for controlling the rolling of a vehicle which is formed of a sill connection shaft provided to connect left and right side sills  130  and a sill connection plate  110  of a vehicle and is able to adjust the inclination of the vehicle with the aid of a steering force transferred from a steering unit, a front axle  140  and a rear axle  150  provided to connect a front wheel  170  and a rear wheel  170  and transfer a steering driving force to each wheel  170 , and a frame  50  which allows to control the inclination of the vehicle with the aid of the rotation of the sill connection shaft  117 , which may include, but is not limited to, a control unit  500  which is able to analyze a steering signal received from a steering operation mechanism  200  and a driving signal received from a driving operation mechanism  400  and generate and transmit a steering control signal and a driving control signal which are used to control the steering unit  100  and the driving unit  300  based on a result value of the analysis; a steering unit  100  which is able to rotate the sill connection shaft  117  in such a way to drive an inclination control motor  185  in response to a steering control signal from the control unit  500  and transfer a steering force to the sill connection shaft  117  and is able to control the driving direction of the vehicle in such a way to incline the frame  50  and the wheel  170  leftward or rightward of the driving direction of the vehicle based on the direction vertical to the ground in accordance with a rotation of the sill connection shaft  117 ; and a driving unit  300  which is able to drive the vehicle in accordance with a driving control signal received from the control unit  500 . 
         [0020]    In the system for controlling the rolling of the vehicle, the vehicle includes a steering link  160  which is provided to connect each wheel  170  and the axle of the vehicle and can be rotatable leftward or rightward of the driving direction of the vehicle with respect to the direction horizontal to the ground, and the steering unit  100  is able to control the driving direction of the vehicle in such a way to incline the frame and the wheel  170  leftward or rightward of the driving direction of the vehicle with respect to the direction vertical to the ground in accordance with a rotation of the sill connection shaft  117  when controlling the driving direction of the vehicle and is able to control the driving direction of the vehicle in such a way to rotate the steering link  160  leftward or rightward with respect to the direction horizontal to the ground. 
         [0021]    Moreover, in the system for controlling the rolling of the vehicle, the vehicle includes a driving motor  310  to transfer a driving force to each wheel  170 , and an electronic transmission to control the driving motor  310 , and the control unit  500  is able to generate a driving control signal to control the speed of the driving motor  310  of each wheel  170  and transfers it to the driving unit  300 , and the driving unit  300  is able to drive the vehicle in such a way to adjust the speed of the driving motor  310  of each wheel in accordance with the received driving control signal. 
         [0022]    Furthermore, the driving unit  300  is able to change the driving direction of the vehicle in the leftward direction in such a way that the speed of the driving motor  310  of the left wheel  170  of the vehicle is decreased, and the speed of the driving motor  310  of the right wheel  170  of the vehicle is increased or maintained and is able to change the driving direction of the vehicle in the rightward direction in such a way that the speed of the driving motor  310  of the right wheel  170  of the vehicle is decreased, and the speed of the driving motor  310  of the left wheel  170  of the vehicle is increased or maintained. 
         [0023]    In the system for controlling the rolling of the vehicle, the steering unit  100  is able to change the driving direction of the vehicle in the rightward direction in such a way that the frame  50  including the wheel  170  is controlled to incline rightward by rotating the sill connection shaft  117  in the rightward direction of the vehicle body and is able to change the driving direction of the vehicle in the leftward direction in such a way that the frame  50  including the wheel  170  is inclined leftward by rotating the sill connection shaft  117  in the leftward direction of the vehicle body. 
         [0024]    Moreover, the system for controlling the rolling of the vehicle may further include a sensor unit which is able to detect a vehicle state information formed of at least one among an inclination, a rotational inertial force, the size of a centrifugal force and an acceleration of the vehicle and transmit the detected information to the control unit  500 . 
         [0025]    In the system for controlling the rolling of the vehicle, the control unit  500  generates a steering control signal in such a way that if a vehicle state information including the size of a centrifugal force is received from the sensor unit, a difference between the size of the centrifugal force and the previously set reference value is obtained, and a compensation value is calculated for the difference to become zero (0), thus generating a steering control signal, and the steering unit  100  is able to control the inclination of the vehicle by rotating the sill connection shaft  117  in accordance with the steering control signal. 
         [0026]    The system for controlling the rolling of the vehicle may further include a tire which is installed at each wheel  170 , and the thread of the tire is formed in a semicircular shape which has a predetermined curvature. 
         [0027]    In addition, the steering signal and the driving signal are PWM (Pulse Width Modulation) signals. 
         [0028]    In the system for controlling the rolling of the vehicle, the steering unit  100  is able to independently control the steering links which are connected to the front axle and the rear axle. 
         [0029]    In another aspect, the present invention provides a method for controlling the rolling of a vehicle, which may include, but is not limited to, (a) a step wherein a steering operation mechanism  200  and a driving operation mechanism  400  receive a steering signal and a driving signal and transfer them to a control unit  500 ; data used to change the driving direction of the vehicle and a data used to drive the vehicle and generates a steering control signal and a driving control signal based on the calculated data and transfers them to the steering unit  100  and the driving unit  300 ; and (d) a step wherein the steering unit  100  controls the driving direction of the vehicle in such a way that the frame including the wheel  170  of the vehicle is inclined leftward or rightward of the driving direction of the vehicle based on the direction vertical to the ground by controlling a sill connection shaft  110  or a steering link  160  in accordance with the received steering control signal or the frame including the wheel  170  of the vehicle is inclined leftward or rightward of the driving direction of the vehicle based on the direction horizontal to the ground, and the driving unit  300  adjusts the speed of a driving motor  310  connected to each wheel  170  in accordance with the received driving control signal. 
         [0030]    In further another aspect, the present invention provides a method for controlling the rolling of a vehicle, which may include, but is not limited to, (a) a step wherein a steering operation mechanism  200  and a driving operation mechanism  400  receive a steering signal and a driving signal and transfer them to a control unit  500 ; (b) a step wherein the control unit  500  analyzes the received steering signal and driving signal; (c) a step wherein the control unit  500  calculates a data used to change the driving direction of the vehicle and a data used to drive the vehicle and generates a steering control signal and a driving control signal based on the calculated data and transfers them to the steering unit  100  and the driving unit  300 ; (d) a step wherein the steering unit  100  controls the driving direction of the vehicle in such a way to rotate the steering link  160  leftward or rightward of the driving direction of the vehicle based on the direction horizontal to the ground; (e) a step wherein a sensor unit detects the vehicle state information of the vehicle and transmits it to the control unit  500 ; and (f) a step wherein the control unit  500  generates a steering control signal by calculating a compensation value with respect to the vehicle state information received from the sensor unit, and the steering unit  100  controls the inclination of the vehicle by rotating a sill connection shaft  117  in accordance with the steering control signal. 
         [0031]    In the method for controlling the rolling of the vehicle, the vehicle state information may include at least one of a rotational inertial force, an inclination of the vehicle, an acceleration, the size of a centrifugal force of the vehicle, etc. 
         [0032]    The system or method for controlling the rolling of the vehicle according to the present invention may further include various technical components within the scope of the present invention by a person having ordinary skill in the art. 
         [0033]    The present invention provides a system for changing the direction of a vehicle in such a way to control the inclinations of a frame and wheels, by means of which the driving safety can be enhanced since the distance between the center of a vehicle body and the ground decreased during the change of the direction of the vehicle. 
         [0034]    In the present invention, it is possible to enhance the durability of tires in such a way that the contacting portions between the tires and the ground change in response to the inclination of the vehicle during the change of the direction of the vehicle. 
         [0035]    Since the driving direction of the vehicle can be controlled based on the control of the inclination and the steering link of the vehicle, the vehicle steering control can be more effectively carried out as compared to the conventional technology. 
         [0036]    In the present invention, the direction of the vehicle can be changed by controlling the driving speed of each wheel, whereupon the steering can be more effectively controlled as compared to the vehicle direction change which is carried using only the steering unit. 
         [0037]    In the present invention, a sensor unit can be further provided, which is able to detect a vehicle state information during the change of the direction of the vehicle, and the driving stability of the vehicle can be enhanced in such a way to control the inclination of the vehicle with the aid of the calculated compensated value which may be used to stabilize the vehicle based on the vehicle state information. 
         [0038]    The advantageous effects of the present invention are not limited to the above-described effects, and various effects may be further provided within a range where a person having ordinary skill in the art can draw from the descriptions below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0039]    The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated the accompanying drawings which are given hereinbelow by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0040]      FIG. 1  is a view illustrating a schematic configuration of a system for controlling the rolling of a vehicle according to an embodiment of the present invention; 
           [0041]      FIG. 2  is a plane view schematically illustrating a frame, a steering unit and a driving unit of a vehicle; 
           [0042]      FIG. 3  is a view illustrating an exemplary operation wherein a control unit receives a steering signal and a driving signal and transmits to the steering unit and the driving unit; 
           [0043]      FIG. 4  is a view illustrating an exemplary structure wherein a sill connection shaft can rotate with the aid of a steering operation unit and a control unit according to an embodiment of the present invention; 
           [0044]      FIG. 5  is a view illustrating an exemplary operation wherein an axle, wheels and tires are inclined during the change of the direction of the vehicle according to an exemplary embodiment of the present invention; 
           [0045]      FIG. 6  is a view illustrating an exemplary operation wherein a vehicle is inclined in the left or right direction of the vehicle driving direction based on the vertical or horizontal direction with respect to the ground or rotates according to an embodiment of the present invention; 
           [0046]      FIG. 7  is a view illustrating a state where the portions contacting with the tires when the vehicle is being driven are classified according to the present invention; 
           [0047]      FIG. 8  is a time series flow chart for describing a method for controlling the rolling of a vehicle according to an embodiment of the present invention; and 
           [0048]      FIG. 9  is a time series flow chart for describing a method for controlling the rolling of a vehicle according to another embodiment of the present invention. 
       
    
    
     LEGEND OF REFERENCE NUMBERS 
       [0000]    
       
         
           
               50 : Frame 
               100 : Steering unit 
               110 : Sill connection plate 
               115 : Metallic member 
               117 : Sill connection shaft 
               120 : Center sill 
               130 : Side sill 
               140 : Front axle 
               150 : Rea axle 
               160 : Steering link 
               170 : Wheel 
               175 : Joint unit 
               180 : Steering link control motor 
               185 : Inclination control motor 
               200 : Steering operation mechanism 
               300 : Driving unit 
               310 : Driving motor 
               400 : Driving operation mechanism 
               500 : Control unit 
           
         
       
     
         [0068]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0069]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0070]    The system for controlling the rolling of a vehicle and a method therefor according to the present invention will be described with reference to the accompanying drawings. The embodiments below are provided to help a person having ordinary skill in the art to easily understand the technical concepts of the present invention, and the ranges of the embodiments of the present invention are not limited thereto. The components shown in the drawings are illustrated for the sake of easier descriptions of the embodiments of the present invention and may be seen different as compared to the actual components. 
         [0071]    Each component below is provided for only illustrative purpose to implement the present invention. In another embodiment of the present invention, another component may be employed without departing from a concept and range of the present invention. Each component may be formed of only a hardware or a software, but various hardware and software may be combined to carry out the same functions. 
         [0072]    The term “comprise” means an open expression to simply indicate a predetermined component, and it should not be interpreted as excluding another component. 
         [0073]    The term “connected” or “linked” means that a predetermined component may be directly connected to another component or it may be connected thereto via another component. 
         [0074]    The system for controlling the rolling of a vehicle according to an embodiment of the present invention will be described with reference to  FIG. 1 . 
         [0075]    Referring to  FIG. 1 , the system for controlling the rolling of the vehicle according to an embodiment of the present invention may include, but is not limited to, a steering unit  100  which is provided to control a driving direction of the vehicle, a driving unit  300  which is provided to control the driving of the vehicle, and a control unit  500  which is provided to control the driving unit  300 . The vehicle may equip with a frame which is able to form the type of the vehicle which includes a function. 
         [0076]    The steering unit  100  is able to carry out a function to control the driving direction of the vehicle. More specifically, it is able to supply a steering force to the sill connection plate  110  in accordance with a steering control signal received from the control unit  500 , thus rotating the sill connection shaft  117 , and carry out a function to control the driving direction of the vehicle in such a way to incline the frame  50  including the wheel  170  leftward or rightward of the driving direction of the vehicle based on the vertical direction with respect to the ground. 
         [0077]    Here, the operation where the wheel is included in the leftward or rightward direction of the driving direction of the vehicle based on the vertical direction with respect to the ground can be easily understood with reference to  FIG. 6 . More specifically, assuming that there may be a virtual surface which is formed vertical with respect to the ground when it is passing through the center of the vehicle, it means that a corresponding vertical surface is inclined in the leftward or right direction of the driving direction of the vehicle. At this time, the wheel  170  of the vehicle may position parallel with the virtual vertical surface, so the driving direction of the vehicle can be controlled in response to the inclination of the wheel. 
         [0078]    The operation where the frame  50  including the wheel  170  is inclined to one side of the driving direction of the vehicle in response to the rotation of the sill connection shaft  117  can be carried out by increasing the angle that the side sills  130  of both sides form with respect to the ground. In case of the rotation of the sill connection shaft  117 , the vehicle can be inclined toward one side since the wheel connected to both the front axle  140  and the rear axle  150  of the vehicle can be inclined at the same angle as the angle that the side sill  130  forms with respect to the ground. More specifically, the steering unit  100  will steer the driving direction of the vehicle toward the rightward direction in such a way that the frame  50  including the wheel  170  is inclined toward the right side of the driving direction of the vehicle with respect to the direction vertical to the ground by rotating the side sill  130  in the rightward direction of the vehicle body, and on the contrary the driving direction of the vehicle can be turned toward the leftward direction since the wheel  170  and the frame  50  are inclined toward the leftward direction by rotating the sill connection shaft  117  toward the leftward direction of the vehicle body. 
         [0079]    Meanwhile, the front axle  140  and the rear axle  150  may be directly connected to the wheel  170  or they may be connected thereto via a link which may be disposed between each axle and the wheel  170  and is able to rotate in the direction perpendicular to the ground. In case where they are connected by using the link between each axle and the wheel  170 , the wheel  170  can be inclined at an angle which is different from the angle that the vehicle is inclined, in response to the rotation of the sill connection shaft  117 . Since it is possible to provide a motion freedom larger than the motion of the wheel  170 , the driver can more smoothly and stably steer the vehicle when changing the driving direction by using the inclination of the vehicle. 
         [0080]    On one hand, the steering unit  100  may include a receiving unit which is able to receive a steering control signal from the control unit  500 , and a plurality of driving force transfer units which are able to transfer the force to rotate the sill connection shaft  117  in response to the received steering control signal. 
         [0081]    On the other hand, the steering unit  100  is able to control the steering link  160  which connects the wheel  170  and the axle of the vehicle and is rotatable leftward or rightward of the driving direction of the vehicle with respect to the direction horizontal to the ground. When controlling the driving direction of the vehicle, the frame  50  including the wheel  170  is inclined leftward or rightward of the driving direction of the vehicle with respect to the direction vertical to the ground in response to the rotation of the sill connection shaft  117 , thus controlling the steering of the vehicle, whereupon the steering of the vehicle can be carried out by rotating the steering link  160  leftward or rightward of the driving direction of the vehicle with respect to the direction horizontal to the ground. 
         [0082]    Meanwhile, it is preferred that the angle that the steering link  160  is able to rotate is above 0° and below 90° with respect to the driving direction of the vehicle. 
         [0083]    Here, the operation where the steering link  160  rotates leftward or rightward of the driving direction of the vehicle with respect to the direction horizontal to the ground will be described in detail with reference to  FIG. 6 . Assuming that there may be a virtual surface which is formed horizontal with respect to the ground when it is passing through the center of the vehicle, it means that the steering link  160  disposed in parallel with the corresponding horizontal surface rotates leftward or rightward of the driving direction of the vehicle. Namely, this is basically same as the vehicle steering method of the typical vehicle to steer the vehicle in the leftward or rightward direction. 
         [0084]    As described in the above operation, the present invention aims to provide a system wherein the direction change of the vehicle can be carried out with the aid of the inclination in the vertical direction with respect to the ground or the rotation in the direction horizontal to the ground or provide a system which is able to change the driving direction of the vehicle by controlling all the two inclinations and the rotation. 
         [0085]    The driving unit  300  will carry out a function to drive the vehicle by supplying the driving force from the inside or outside of the vehicle. More specifically, the driving unit  300  will carry out a function to receive a driving control signal from the control unit  500  and a driving force to drive the vehicle and drive the vehicle in response to the received driving control signal. 
         [0086]    Meanwhile, the driving unit  300  may preferably include a receiving unit to receive a driving control signal from the control unit  500 , and a plurality of driving force transfer units which are able to transfer force to drive the wheel  170  connected to the front axle  140  and the rear axle  150  in accordance with the received driving control signal when carrying out the driving control function. 
         [0087]    Moreover, the vehicle may include a driving motor  310  to individually transfer the driving force to each wheel  170 , and an electronic transmission to control the driving motor. The control unit  500  will generate a driving control signal to control the speed of the driving motor  310  connected to each wheel  170  and will transfer the signal to the driving unit  300 , and the driving unit  300  may drive the vehicle in such a way to adjust the speed of each driving motor  310  in response to the received driving control signal. Meanwhile, the driving motor may be connected with a suspension device to support the weight of the vehicle and reduce the up and down vibrations of the vehicle. Different from the conventional configuration wherein the driving force generated by one driving motor  310  is transferred to each wheel  170  of the vehicle via a gear or a shaft, the driving motor  310  is provided at each wheel  170 , thus individually controlling the wheels  170  of the vehicle. If an independent driving control with respect to each wheel  170  is made possible in such a way to provide the driving motor  310  to each wheel  170 , the safety and driving force of the vehicle can be more improved as compared to the conventional driving method. Since the driving force to each wheel  170  can be distributed during the driving, the braking energy recovery due to the recovery braking can be maximized during the braking, whereupon the energy efficiency to drive the vehicle can be maximized. Moreover, If the independent driving control is obtained by providing the driving motor  310  at each wheel, all the power train components which were necessary for the vehicle can be removed, which may result in the simplified structure of the vehicle, and since each wheel  170  can be individually controlled, it is advantageous to effectively adjust the driving, braking and steering of the vehicle. 
         [0088]    Moreover, in a state where the independently operable driving motor  310  is provided at each wheel  170  of the vehicle, the driving unit  300  is able to increase the driving motor  310  of the right wheel  170  of the vehicle while reducing the speed of the driving motor  310  of the left wheel  170  of the vehicle, thus making it possible to turn the driving direction of the vehicle toward the leftward direction. In similar ways, the driving direction of the vehicle can be changed toward the right direction. 
         [0089]    According to the present invention, the driving direction change of the vehicle can be carried out by any of the methods wherein (i) the vehicle is inclined leftward or rightward of the driving direction of the vehicle based on the direction vertical to the ground, (ii) the vehicle can turn leftward or rightward of the driving direction of the vehicle based on the direction horizontal to the ground, and (iii) the driving speeds of the left wheel  170  and the right wheel  170  of the vehicle are adjusted in a state where the driving motor  310  is individually provided at each wheel  170 . 
         [0090]    The configuration of the vehicle which will be controlled according to the present invention will be described with reference to  FIG. 2 . 
         [0091]      FIG. 2  is a plane view illustrating a vehicle which equips with a system for controlling the rolling of a vehicle according to an embodiment of the present invention. 
         [0092]    As a main component of the frame  500  to control the driving direction of the vehicle based on the inclination of the vehicle, there are a sill connection plate  110  provided to allow the left and right sills  130  of the vehicle to be supported simultaneously movable, and a sill connection shaft  117  which is able to incline the side sill. 
         [0093]    The sill means a piece member which is able to support the lower side of a predetermined device. The side sill  130  in the vehicle means a member which is provided at the lower end portions of both sides of the vehicle and is able to support the whole weight of the vehicle. A center sill  120  means a member which is provided between the side sills  130  and is able to support the weight at the central portion of the vehicle. Since the key object of the present invention is to change the driving direction of the vehicle by inclining the vehicle body, the side sill  130  and the center sill  120  are preferably provided separates from each other, whereupon each sill can be individually inclined when the vehicle body is inclined. 
         [0094]    Meanwhile, the sill connection plate  110  means a plate which is able to support the side sill  130 . It is a connection plate which may allow the side sills  130  at both sides to be simultaneously inclined when the vehicle is inclined to one side. Since a technology wherein a plurality of members arranged in parallel are connected with one connection plate and are inclined in the same direction in terms of their motions would be easily carried out by a person having ordinary skill in the art, the description thereon will be omitted. An additional metallic member may be added to the sill connection plate  110 , thus enhancing the strength of the connection portion of the side sills  130 . 
         [0095]    Meanwhile, the sill connection plate  110  and the side sills  130  are connected via the sill connection shaft  117 . If the sill connection shaft  117  rotates by receiving the force from the inclination control motor  185 , the left and right side sills  130  will rotate about the sill connection shaft  117 , thus inclining the vehicle. More specifically, the sill connection shaft  117  will rotate in response to a steering control signal of the steering unit, whereby the side sills  130  are inclined, thus controlling the driving direction of the vehicle. Here, the driving force that the sill connection shaft  117  needs to rotate can be generated by the inclination control motor  185 . The transfer of the driving force can be carried out by the sill connection plate  110 . 
         [0096]    The transfer of the driving force to rotate the sill connection shaft  117  may be carried by two methods. The first method is to use the driving force transfer shaft and gear which are provided at the sill connection plate  110 . If the inclination control motor  185  generates driving force in response to a steering control signal, the driving force can be transferred via the driving force transfer shaft and the gear to the sill connection shaft  117  which is connecting the side sills  130  and the sill connection plate  110 . The second method is to provide another axle (a second axle) which is in parallel with the front axle  140  or the rear axle  150  and connect the corresponding axle and the wheel  170  to a joint unit which can be inclined, and transfer the driving force generated by the inclination control motor  185  to the axle. The second method has a difference as compared to the second method in the way that the driving force generated by the inclination control motor  185  is transferred to the joint unit which is connecting each wheel and the second axle. At this time, the function of the joint unit may correspond to the sill connection shaft  117  of the first method, and if necessary, it may be substituted with the sill connection shaft  117 . 
         [0097]    Meanwhile, the vehicle equips with the front axle  140  and the rear axle  150 , and the wheel  170  is provided at both ends of each axle to steer the vehicle as it turns about the shaft and support the weight of the vehicle. According to the embodiment of the present invention, the axle and the wheel  170  may be connected with the steering link  160  being interposed between them. The steering link  160  may include a joint which may rotate in the direction vertical or horizontal with respect to the ground, whereby the vehicle can incline leftward or rightward based on the direction vertical with respect to the ground or can rotate leftward or rightward based on the direction horizontal with respect to the ground. 
         [0098]    Moreover, a steering link control motor  180  is connected to the axle so as to transfer driving force which is able to rotate the steering link (A)  160  when the vehicle changes the driving direction based on the direction horizontal with respect to the ground. The steering link control motor  180  may be connected to the front axle  140  or the rear axle  150 , thus individually controlling the steering link (B)  160  which is connecting the front axle  140  and the wheel  170 . In case where the steering links (A and B) of the front axle  140  and the rear axle  150  are individually controlled, it is possible to greatly reduce the rotation radius as compared to when the vehicle turns by rotating only the steering link (A)  160  of the front axle  140  as in the conventional technology. The movement trajectory of the vehicle may be made to look like a straight line in such a way that the steering links of both the axles are rotated rather than to change the lane by rotating only the steering link of one front axle or one rear axle during the change of the lane. Moreover, it is possible to advantageously reduce any inertial force and instability of the vehicle body which may occur since the vehicle turns along a curved trajectory during the change of the lane. 
         [0099]    For example, if it needs to change the lane of the road, the steering unit  100  steers the steering link connected to the front axle to turn 20° in the leftward direction with respect to the driving direction of the vehicle, and steers the steering link connected to the rear axle to turn 20° in the left direction, whereupon the vehicle can change the lane while moving along a trajectory which looks like a straight line, not a curved line. 
         [0100]    If the vehicle makes a U-turn on the road, the steering unit  100  steers the steering link connected to the front axle to turn 45° in the leftward direction with respect to the driving direction of the vehicle and steers the steering link connected to the rear axle to turn 45° in the rightward direction, whereby the vehicle can make a U-turn along a smaller rotation trajectory as compared to the conventional technology. 
         [0101]    According to another embodiment of the present invention, the wheel  170  may individually equip with a driving motor  310  and an electronic transmission, and each driving motor and electronic transmission are able to individually adjust the driving speed of each wheel  170  in response to a driving control signal generated by the control unit  500 . 
         [0102]    The flows of various control signals according to an embodiment of the present invention will be described with reference to  FIG. 3 . 
         [0103]    Referring to  FIG. 3 , the steering signal and the driving signal are transmitted from each steering operation mechanism  200  or driving operation mechanism  400  to the control unit  500 , and the control unit  500  will generate a steering control signal or a driving control signal and transmit the generated steering control signal or driving control signal to each steering unit  100  or driving unit  300 . 
         [0104]    The steering operation mechanism  200  is a mechanism which is able to receive the driving direction of the vehicle based on a driver&#39;s intention when the driver wants to change the driving direction of the vehicle. As an example, the steering mechanism  200  may be a handle provided in front of the driver. The method that the steering operation mechanism  200  receives the driving direction of the vehicle from the driver is not limited. The steering operation mechanism  200  may include any component as long as it is able to transfer the driver&#39;s intention to change the driving direction of the vehicle. Meanwhile, the steering operation mechanism  200  will convert the driving direction input of the vehicle received from the driver into an electrical signal and transfer it to the control unit  500 . The electrical signal may be a PWM (Pulse Width Modulation) signal. 
         [0105]    The driving operation mechanism  400  is a mechanism to receive a driving time, a driving speed, etc. of the vehicle in accordance with the driver&#39;s intention when the driver is about to give a command on the driving of the vehicle. It may be, for example, an accelerator which is provided in the driver&#39;s compartment. The method that the driving operation mechanism  400  receives the command on the driving of the vehicle from the driver is not limited. The steering operation mechanism  400  may include any component as long as it is able to transfer the driver&#39;s command on the driving of the vehicle. Meanwhile, the driving operation mechanism  400  may convert the vehicle driving command received by the driver into an electrical signal and transfer to the control unit  500 . The electrical signal may be a PWM (Pulse Width Modulation) signal. 
         [0106]    Meanwhile, the control unit  500  will carryout a predetermined calculation with respect to the received steering signal or driving signal, thus generating a steering control signal or a driving control signal. 
         [0107]    More specifically, the control unit  500  is able to extract from the received steering signal the data, for example, the driving direction of the vehicle which is supposed to change its driving direction, a turning amount, etc. that the driving direction of the vehicle turns. A steering control signal formed of the driving direction of the vehicle, a vehicle body inclination angle, left and right rotation angles of the steering link  160 , etc. which are necessary when to change the driving direction of the vehicle can be generated based on the extracted data. 
         [0108]    Moreover, the control unit  500  is able to extract from the received driving signal the data, for example, the driving direction of the vehicle, the speed and acceleration of the vehicle, etc., and a driving control signal formed of an information on whether or not the vehicle is currently in the turning section, an output amount necessary for the driving speed and acceleration of the vehicle, the driving speed of the individual wheel  170  necessary for the change of the driving direction of the vehicle, etc. can be generated based on the extracted data. 
         [0109]    Meanwhile, the steering unit  100  will change the driving direction of the vehicle by receiving a steering control signal from the control unit  500 , which will be carried out in such a way that the sill connection plate  117  is rotated, and the vehicle body including the wheel  170  is inclined leftward or rightward of the driving direction of the vehicle based on the direction vertical with respect to the ground, and the steering link  160  is rotated leftward or rightward of the driving direction of the vehicle based on the direction horizontal with respect to the ground. 
         [0110]    Moreover, the driving unit  300  will drive the vehicle by receiving a driving control signal from the control unit  500 , which can be caused in such a way to supply a driving force to one or more than one driving motor  310 . If the driving motor  310  is multiple in number, the driving unit  300  is able to adjust the driving speed of each driving motor  310  while simultaneously changing the driving direction of the vehicle of the steering unit  100  in accordance with the driving control signal, whereupon the change of the driving direction of the vehicle can be more effectively carried out. For example, if the vehicle is intended to turn in the leftward direction, the direction change to the leftward direction can be carried out by the steering unit  100 , and the driving unit  300  will decrease the driving speed of the wheel  170  positioning at the left side of the wheel or increase or maintain the driving speed of the wheel  170  positioning at the right side, whereby the vehicle can be controlled to carry out the turning in the leftward direction. 
         [0111]      FIG. 4  is a view schematically illustrating a connection relationship between the steering operation mechanism  200 , the control unit  500 , the steering unit  100  and the sill connection plate  110 . 
         [0112]    Referring to  FIG. 4 , since the steering operation mechanism  200  is directly connected to the control unit  50 , the input on the driving direction of the vehicle can be transferred. At this time, the transferred input signal will be converted into an electrical signal as mentioned previously and will be transferred as a steering signal. The control unit  500  will generate a steering control signal based on the received steering signal and transfer it to the steering unit  100 . The steering unit  100  will transfer a driving force to rotate the sill connection shaft via the sill connection plate  110  based on the received steering control signal, thus rotating the sill connection shaft  117  and controlling the change of the driving direction of the vehicle. 
         [0113]    In the embodiment in  FIG. 4 , it was assumed that the turning of the vehicle is carried out in such a way that the driving direction of the vehicle is inclined leftward or rightward of the driving direction of the vehicle based on the direction vertical with respect to the ground. As mentioned above, based on the changing method of the driving direction of the vehicle, the portions that the steering unit  100  can control may be the sill connection shaft  117 , the steering link  160 , etc. 
         [0114]      FIG. 5  is a view illustrating a state where the frame  50  including the wheel  170  is inclined with respect to the direction vertical to the ground during the driving of the vehicle according to an embodiment of the present invention. 
         [0115]      FIG. 7  is a view illustrating a state where the tires are contacting with the ground during the driving of the vehicle according to another embodiment of the present invention. 
         [0116]    As illustrated in  FIG. 7 , the vehicle is driven with the threads (the wide portions between the tires and the ground) being contacting with the ground in a state where the tires are not inclined when the vehicle goes straight. Meanwhile, if the vehicle turns left, the tires will go with apart of the thread as indicated by the dotted line in the drawing as well as a part of the side wall (a side surface) of the tires being contacting with the ground. 
         [0117]    Since the portions that the tires are contacting with the ground are different for each driving situation, the wear rates of the tires can be lowered while enhancing resource use efficiency in such a way to minimize the wears of the tires against the ground according to the present invention. 
         [0118]    Meanwhile, each of the tires in general is formed in a semicircular shape wherein a thread has a curvature over a predetermined value. In this case, the area that the thread is contacting with the ground may be more decreased, whereupon it is possible to effectively reduce the wear rates of the tires. 
         [0119]      FIG. 8  is a view for describing the method for controlling the rolling of the vehicle according to the present invention. 
         [0120]    Referring to  FIG. 8 , the method for controlling the rolling of the vehicle according to an embodiment of the present invention may include a step S 110  wherein the steering operation mechanism  200  and the driving operation mechanism  400  receive a steering control signal and a driving signal and transfer to the control unit  500  (S 110 ). At this time, the steering signal or the driving signal transferred to the control unit  500  may be electrical signal which have been converted in the steering operation mechanism  200  and the driving operation mechanism  400 , in particular, they may be PWM (Pulse Width Modulation) signals. The control unit  500  may include a step to analyze the received steering signal and driving signal (S 120 ). The above analysis is to extract the information from the steering signal and the driving signal, which may be necessary to change the driving direction of the vehicle or provide a driving command. In particular, if the signal is a PWM signal, the control unit  500  may be able to extract the information in such a way to analyze a rising edge, a falling edge, a delay, etc. of the transmitted signal. 
         [0121]    As a result of the analysis in the step S 120 , the control unit  500  is able to calculate the driving direction of the vehicle, the data which would be necessary to change the driving direction of the vehicle, for example, the turning amount for the sake of the driving direction of the vehicle, and the data which would be necessary to drive the vehicle, for example, the speed of the driving motor  310 . The steering control signal and the driving control signal can be generated based on the calculated data and will be transmitted to the steering unit  100  and the driving unit  300  (S 130  and S 140 ). At this time, the steering control signal may be formed of the driving direction of the vehicle, the vehicle body inclination angle which is necessary to change the driving direction, and the rotation angle of the steering link  160 , etc. The driving control signal may be formed of the information on whether or not the vehicle is currently in the turning section, the output amount necessary for the driving speed and acceleration of the vehicle, and the information, for example, on the driving speed of the individual wheel  170  which is necessary to change the driving direction of the vehicle. 
         [0122]    Meanwhile, after the steering unit  100  receives the steering control signal, the steering unit  100  will control the driving direction of the vehicle in such a way to incline the frame  50  including the wheel  170  of the vehicle leftward or rightward of the driving direction of the vehicle based on the direction vertical to the ground or rotating the steering link  160  leftward or rightward of the driving direction of the vehicle based on the direction horizontal to the ground, both the operations of which can be carried out by controlling the sill connection plate  110  or the steering link  160  in response to the received steering control signal. The driving unit  300  will change the driving direction of the vehicle in such away to adjust the speed of the driving motor  310  connected to the wheel  170  in accordance with the received driving control signal. 
         [0123]      FIG. 9  is a view for describing the method for controlling the rolling of the vehicle according to another embodiment of the present invention. 
         [0124]      FIG. 9  shows the method for controlling the rolling of the vehicle which is able to minimize any instability due to the rotational inertial force of the vehicle during the operation wherein the driving direction of the vehicle is changed based on the direction horizontal to the ground. 
         [0125]    Referring to  FIG. 9 , the method for controlling the rolling of the vehicle according to an embodiment of the present invention may include a step S 210  wherein the steering operation mechanism  200  and the driving operation mechanism  400  receive the steering signal and the driving signal and transfer them to the control unit  500 . The control unit  500  will analyze the received signals and will calculate the data to change the driving direction of the vehicle and the data which are necessary for the driving of the vehicle and will generate a steering control signal and a driving control signal based on the calculated data and transfer them to the steering unit  100  and the driving unit  300  (S 220 ). 
         [0126]    According to an embodiment of the present invention, the steering unit  100  will control the driving direction of the vehicle by rotating the steering link  160  leftward or rightward of the driving direction of the vehicle based on the direction horizontal to the ground in according to the received steering control signal (S 230 ). More specifically, the present invention is directed to the method for controlling the rolling of the vehicle so as to reduce any instability which might occur due to the rotational inertial force or the centrifugal force when the vehicle is turning in the horizontal direction. 
         [0127]    Meanwhile, when the driving direction of the vehicle is being changed in the above manner, the sensor unit may include a step S 240  to detect the vehicle state information of the vehicle and transmit it to the control unit  500 . The vehicle state information may be formed of the rotational inertial force of the current vehicle, the angle that the vehicle has inclined due to the turning of the vehicle, the acceleration of the vehicle and the level of the centrifugal force. Here, the centrifugal force means an inertial force that in general generates at the turning vehicle and has the same size as the centripetal force and the opposite direction to it. The centrifugal force has a force which is applying in the direction where it moves away from the center of the rotational radius. The unit of the centrifugal force size is N (Newton) or dyn. 
         [0128]    Meanwhile, the control unit  500  may include steps S 250  to  270  wherein a steering control signal is generated by calculating the compensation value with respect to the vehicle state information, and the steering unit  100  will adjust the inclination of the vehicle by controlling the sill connection plate. At this time, the compensation value means a predetermined value to minimize any instability of the vehicle during the change of the driving direction of the vehicle, more specifically, a value to minimize any change in the inclination of the vehicle due to the centrifugal force. According to the present invention, even though any instability factor occurs during the change of the driving direction of the vehicle, the method for controlling the rolling of the vehicle is able to minimize such an instability factor according to an embodiment of the present invention. 
         [0129]    The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.