reference will now be made in detail to various embodiments of the present invention ( s ), examples of which are illustrated in the accompanying drawings and described below . while the invention ( s ) will be described in conjunction with exemplary embodiments , it will be understood that present description is not intended to limit the invention ( s ) to those exemplary embodiments . on the contrary , the invention ( s ) is / are intended to cover not only the exemplary embodiments , but also various alternatives , modifications , equivalents and other embodiments , which may be included within the spirit and scope of the invention as defined by the appended claims . fig1 is a drawing showing an active geometry control suspension according to various embodiments of the present invention . as shown in fig1 , an active geometry control suspension ( agcs ) 1 according to various embodiments of the present invention includes an assist link 10 including a first link 11 of which an end is rotatably connected to a vehicle body 12 and a second link 13 of which an end is connected to the first link 11 and the other end is rotatably connected to a wheel 14 , a clutch assembly 20 selectively connecting a connecting portion of the first link 11 and the second link 13 to the vehicle body 12 and a driving unit 30 operating the clutch assembly 20 . the assist link 10 induces understeering of vehicle for providing turning stability . the assist link 10 connects the wheel 14 to the vehicle body 12 . in this case , toe - in of an inside wheel of a rear wheel ( a wheel to bump ) and toe - out of an outside wheel of the rear wheel ( a wheel to rebound ) may induce turning stability . for example , the active geometry control suspension 1 increases roll steer of the outside wheel of the rear wheel , that is , toe - in is increased compared to toe - in when the agcs 1 is not operated . thus , the assist link 10 increases cornering force to a rear wheel during cornering the circular path so that the vehicle may be induced in under steer condition and handling performance may be enhanced . the assist link 10 may connect the wheel 14 and the vehicle body 12 through a knuckle . the assist link 10 includes the first link 11 of which the end is rotatably connected to a vehicle body 12 and the second link 13 of which the end is connected to the first link 11 and the other end is rotatably connected to a wheel 14 . the end of the first link 11 may be directly connected to the vehicle body 12 . the first link 11 is rotatably connected to the vehicle body 12 and is rotatable when the wheel 14 bumps or a vehicle turns in high speed . a bracket 15 is disposed to connecting the first link 11 and the second link 13 . the bracket 15 is mounted to the other end of the first link 11 . the bracket 15 includes a plate 15 a mounted to the other end of the first link 11 and a pair of supporting portion 15 b protruded from the plate 15 a . a rotating shaft 17 is disposed between the supporting portions 15 b and the second link 13 is rotatably connected to the rotating shaft 17 . the clutch assembly 20 is configured to a connecting portion of the first link 11 and the second link 13 . the clutch assembly 20 selectively connects the connecting portion ( it is indicated as “ a ”) of the first link 11 and the second link 13 to the vehicle body 12 . the release operation of the clutch assembly 20 releases the connecting portion a from the vehicle body 12 and induces understeering of the rear wheel when the wheel 14 bumps or a vehicle turns in high speed . the clutch assembly 20 includes a first disk 21 disposed to the other end of the first link 11 and a second disk 23 selectively connected to the first disk 21 by an operation of the driving unit 30 . the first disk 21 is protruded fixed to a side of the bracket 15 . the first disk 21 and the second disk 23 may be selectively engaged each other . or , the first disk 21 and the second disk 23 may have concave and convex shape respectively or vice versa for engagement . the second disk 23 may be slid to be connected to the first disk 21 by the operation of the driving unit 30 . the connection of the first disk 21 and the second disk 23 is released for inducing understeering when a vehicle turns in high speed or a wheel bumps . hereinafter , toe - in of an outside wheel of rear wheels will be explained referring operations of the assist link 10 including connection and release of the first disk 21 and the second disk 23 . connecting state of the first disk 21 and the second disk 23 will be described . fig3 is a drawing showing operations of an assist link in connecting state of the first disk and the second disk . as shown in fig1 and fig3 , when the first disk 21 and the second disk 23 are connected by the connecting operation of the driving unit 30 , the second link 13 functions as a general assist link by itself . that is , both ends of the first link 11 are fixed to the vehicle body 12 so that the second link 13 can rotate by itself and function as a general assist link . when the first disk 21 and the second disk 23 are connected , toe - in is relatively small so that abrasion of tires can be prevented and stability in straight driving can be enhanced . hereinafter , release state of the first disk 21 and the second disk 23 will be explained . fig2 is a drawing showing an active geometry control suspension of which a first disk and a second disk are released and fig4 is a drawing showing tracks of the assist link in connecting state and released state of the first disk and the second disk . fig2 and as shown in fig4 , if the first disk 21 and the second disk 23 are released by an release operation of the driving unit 30 when the wheel 14 bumps or a vehicle turns in high speed , both the first link 11 and the second link 13 function as an assist link . in this state , the first link 11 can rotate about a connection point b of the first link 11 and the vehicle body vehicle 12 and thus both the first link 11 and the second link 13 function as an assist link . in the drawing , bending may be generated between the second link 13 and the first link 11 , because the second link 13 and the first link 11 are rotatable to each other . thus , toe - in can be easily generated when the wheel 14 bumps or a vehicle turns in high speed and that induces under steer conditions and handling performance may be enhanced . in the mean time , the driving unit 30 can be formed by an actuator connected to the second disk 23 via a rod 31 . the actuator can be configured to the vehicle body 12 and selectively fix the connecting portion a to the vehicle body 12 . in various embodiments of the present invention , the actuator may include a hydraulic actuator or an electromagnetic actuator so that the second disk 23 may move upwards or downwards by the solenoid . from another angle , operations of the active geometry control suspension according to various embodiments of the present invention will be explained . as shown in fig3 , the second link 13 functions as an assist link when the connecting portion a of the assist link 10 is fixed to the vehicle body 12 . as shown in fig4 , the connecting portion a can be moved to a ′ in the drawing by release operation of the driving unit 30 when the wheel 14 bumps or a vehicle turns in high speed . in the drawing , while the position of the connecting portion a ′ is turned around the b for better comprehension and ease of description , it is not limited to the description . that is , the first link 11 and the second link 13 simultaneously rotate around the poison b and induce toe - in . comparing to the state that the connecting portion a in fig3 is connected to the vehicle body 12 , the wheel 14 can be moved inwardly so that toe - in can be easily induced . referring to fig4 , c is a track of the assist link 10 when the driving unit 30 is controlled to connect the connecting portion a to the vehicle body 12 and c ′ is a track of the assist link 10 when the driving unit 30 is controlled to release the connecting portion a from the vehicle body 12 . as shown in fig4 c ′ is positioned relatively inward to the vehicle body 12 . as described above , the assist link 10 according to various embodiments of the present invention may easily induce toe - in when the wheel 14 bumps or a vehicle turns in high speed so that driving performance can be improved . for convenience in explanation and accurate definition in the appended claims , the terms “ inside ”, “ rear ”, and “ front ” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures . the foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description . they are not intended to be exhaustive or to limit the invention to the precise forms disclosed , and obviously many modifications and variations are possible in light of the above teachings . the exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application , to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention , as well as various alternatives and modifications thereof . it is intended that the scope of the invention be defined by the claims appended hereto and their equivalents .