Patent ID: 8321091

Claim:
A car connected to at least one trailer comprising: a driving part controlling a velocity and a direction of the car; a backward-motion control terminal outputting a first backward-motion control signal corresponding to at least one of a backward velocity and a backward direction of the last trailer according to a user's operation; a control signal converter converting the first backward-motion control signal to a second backward-motion control signal which corresponds to at least one of a backward velocity and a backward direction of the car and makes the last trailer move backward as at least one of the backward velocity and the backward direction corresponding to the first backward-motion control signal; and a backward-motion controller controlling the driving part on the basis of the second backward-motion control signal so that the last trailer moves backward by at least one of the backward velocity and the backward direction corresponding to the first backward-motion controlling signal wherein the first backward-motion control signal comprises a first linear velocity and a first angular velocity for the last trailer, the second backward-motion control signal comprises a second linear velocity and a second angular velocity corresponding to a backward-motion of the car, and the control signal converter converts the first backward-motion control signal to the second backward-motion control signal by the following equation: A ⁡ [ ( - 1 ) n - 1 ⁢ cos ⁢ ⁢ Ψ n ( - 1 ) n - 1 ⁢ d car ⁢ sin ⁢ ⁢ Ψ n sin ⁢ ⁢ Ψ n d trailer - cos ⁢ ⁢ Ψ n ] ⁡ [ v 0 w 0 ] = [ v n w n ] A = 1 ( - 1 ) n - 1 ⁢ ( cos 2 ⁢ Ψ n + d car d trailer ⁢ sin 2 ⁢ Ψ n ) , ⁢ Ψ i = ∑ k = 1 i ⁢ ⁢ ( - 1 ) k - 1 ⁢ ( θ k - 1 - θ k ) , i = 1 , … ⁢ , n wherein v 0 is a linear velocity of the car, W 0 is an angular velocity of the car v n is a linear velocity of the nth trailer, w n is an angular velocity of the nth trailer, θ i is a joint angle between the ith trailer and the i-lth trailer or between the car and the first trailer, d car is a length of a connecting link of the car, and d trailer is a length of a connecting link of the trailer.