Patent ID: 7174244

Claim:
A method for controlling a vehicle suspension system, the vehicle suspension including a plurality of dampers and a plurality of actuators, the vehicle suspension system being represented by an equation (1) and being transformed to a decoupled equation (2), the method comprising: calculating a velocity vector {dot over (x)}(t) of a state vector x(t) of the equation 1; calculating an actuating force f(t) such that the actuating force f(t) satisfies { â¢ if â¢ â¢ Q 1 â¢ j â¢ sign â¡ ( Î¾ . 1 ) â‰¥ â‹¯ Q nj â¢ sign â¡ ( Î¾ . n ) â‰¥ 0 , â¢ f j = - F A 0 & â¢ Q 2 â¢ j â¢ sign â¢ â¢ ( Î¾ . 2 ) â‰¥ 0 & if â¢ â¢ Q 1 â¢ j â¢ sign â¡ ( Î¾ . 1 ) â‰¥ â‹¯ Q nj â¢ sign â¡ ( Î¾ . n ) < 0 , â¢ f j = - F 1 0 & â¢ Q 2 â¢ j â¢ sign â¢ â¢ ( Î¾ . 2 ) â‰¥ 0 & â‹® â‹® if â¢ â¢ Q 1 â¢ j â¢ sign â¡ ( Î¾ . 1 ) < â‹¯ Q nj â¢ sign â¡ ( Î¾ . n ) â‰¥ 0 , â¢ f j = - F ( 2 n - 2 ) 0 & â¢ Q 2 â¢ j â¢ sign â¢ â¢ ( Î¾ . 2 ) < 0 & if â¢ â¢ Q 1 â¢ j â¢ sign â¡ ( Î¾ . 1 ) < â‹¯ Q nj â¢ sign â¡ ( Î¾ . n ) < 0 , â¢ f j = - F B 0 & â¢ Q 2 â¢ j â¢ sign â¢ â¢ ( Î¾ . 2 ) < 0 & â¢ } with respect to i=1, . . . , n and j=1, . . . , p; and actuating the actuators by the calculated actuating force f(t), wherein: F A is a value in a range of zero (0) to F P ; F B is a value in a range of zero (0) to F N ; F k for k=1, . . . , (2 n âˆ’2) is a value between F P and F N ; F P and F N respectively denote a positive maximum force and a negative maximum force that a j th actuator can generate; the equation (1) is M{umlaut over (x)} ( t )+ C ( {dot over (x)} ( t )âˆ’ {dot over (u)} ( t )+ K ( x ( t )âˆ’ u ( t ))= Pf ( t ); and the equation (2) is I{umlaut over (Î¾)} ( t )+diag[2Î¶ i Ï‰ i ]({dot over (Î¾)}( t )âˆ’{dot over (Î·)}( t ))+Î› K (Î¾( t )âˆ’Î·( t ))={circumflex over (f)}( t ) wherein: n and p respectively denote the number of degrees of freedom of the suspension system and the number of independent actuators; M, C, and K respectively denote a mass matrix, a damping matrix, and a stiffness matrix, each of which is symmetrically nÃ—n, the mass matrix M being a positive definite matrix, the damping matrix C being a positive semi-definite matrix, and the stiffness matrix K being a positive definite matrix; P denotes an nÃ—p real matrix corresponding to positions of the actuators, x(t) and u(t) respectively denote nÃ—1 state and disturbance vectors; f(t) denotes a pÃ—1 external force vector; I is an nÃ—n unit matrix; S is a matrix consisting of eigenvectors of the stiffness matrix K and is normalized with respect to the mass matrix M; and Q=S T P, {circumflex over (f)}=Qf(t), x(t)=S Î¾(t), u(t)=SÎ·(t), S T KS=diag[Ï‰ i 2 ]=Î› K , and S T CS=Äˆ=diag[2Î¶ i Ï‰ i ] are satisfied by the matrix S.