Patent ID: 7418326

Claim:
A steer-by-wire system comprising: a steering handle disconnected mechanically from a pair of steerable wheels; a steering motor for steering the steerable wheels in dependence on the manipulation of the steering handle; a reaction force motor for generating a steering reaction force against the manipulation of the steering handle; road reaction force detection means for detecting a road reaction force acting on the steerable wheels; first made-up value determination means for determining a first steering reaction force made-up value (Hc 1 ) in dependence on the road reaction force detected by the road reaction force detection means; steering position detection means for detecting the steering position of the steering handle or the steerable wheels away from a neutral position; second made-up value determination means for determining a second steering reaction force made-up value (Hc 2 ) in dependence on the steering position detected by the steering position detection means; and command value generation means for determining first and second gains (G 1 , G 2 ) so that relations G 1 ≦C, G 2 ≦C and G 1 +G 2 =C can be satisfied where symbols G 1 , G 2 and C are taken respectively as first gain, second gain and predetermined constant, and for generating a steering reaction command value (H) which makes the reaction force motor generate the steering reaction force, by the following expression: H=G 1· Hc 1+ G 2· Hc 2 using the first and second gains (G 1 , G 2 ).