Vehicle

1. A vehicle having a step plate on which a rider rides and that performs a turning movement based on a rotation of the step plate in a left/right direction, comprising:

a restriction mechanism to allow the rotation of the step plate in the left/right direction to be restricted;

a first control unit to control the restriction mechanism so that the rotation of the step plate in the left/right direction is restricted when the rider gets on the step plate or the rider gets off the step plate;

a first detection unit to detect a rotation angle of the step plate; and

a second detection unit to detect a load exerted on the step plate, wherein

the first control unit starts getting-off assist control in a state where the rotation of the step plate in the left/right direction is permitted; when determined that the step plate is in a roughly horizontal state based on the rotation angle of the step plate detected by the first detection unit, controls the restriction mechanism so that the rotation of the step plate in the left/right direction is restricted; and when determined that the rider has gotten off the step plate based on the load exerted on the step plate that is detected by the second detection unit, finishes the getting-off assist control in a state where the rotation of the step plate in the left/right direction is restricted, and

the first control unit starts getting-on assist control in the state where the rotation of the step plate in the left/right direction is restricted; when determined that the rider has gotten on the step plate based on the load exerted on the step plate that is detected by the second detection unit, controls the restriction mechanism so that the rotation of the step plate in the left/right direction is permitted; and finishes the getting-on assist control in the state where the rotation of the step plate in the left/right direction is permitted.

2. The vehicle according to claim 1 , further comprising:

a first operation unit that is operated by the rider to perform a turning movement of the vehicle; and

a second control unit to control a wheel either in a turning mode of the vehicle based on an operation of the first operation unit or in a turning mode of the vehicle based on a rotation of the step plate in the left/right direction.

3. The vehicle according to claim 2 , wherein the second control unit makes switching to the turning mode of the vehicle based on the operation of the first operation means available when the restriction mechanism is restricting the rotation of the step plate in the left/right direction.

4. The vehicle according to claim 1 , further comprising a second operation unit that is operated by the rider to make the restriction mechanism restrict or permit the rotation of the step plate in the left/right direction.

5. The vehicle according to claim 1 , further comprising a vehicle main body that supports the step plate, wherein

the vehicle main body is a parallel linkage configured to rotate in the left/right direction, the parallel linkage comprising top and bottom horizontal links and left and right vertical links, and the step plate being disposed on an upper end of each of the left and right vertical links, and

the restriction mechanism restricts the rotation of the step plate in the left/right direction by restricting a rotation of the vehicle main body.

6. The vehicle according to claim 5 , wherein the restriction mechanism comprises a restriction piece that protrudes under control of the first control unit, the restriction mechanism being disposed near a connecting portion between the horizontal link and the vertical link and being configured so that the protruded restriction piece comes into contact with the horizontal link or the vertical link and thereby restricts a rotation of the vehicle main body in the left/right direction.

7. The vehicle according to claim 1 , further comprising a vehicle main body, the vehicle main body being connected to the step plate through a rotation shaft so as to permit the rotation of the step plate in a left/right direction,

wherein the restriction mechanism restricts the rotation of the step plate in the left/right direction by restricting a rotation of the rotation shaft.

8. A vehicle having a step plate on which a rider rides and that performs a turning movement based on a rotation of the step plate in a left/right direction, comprising:

restriction means to allow the rotation of the step plate in the left/right direction to be restricted;

first control means to control the restriction means so that the rotation of the step plate in the left/right direction is restricted when the rider gets on the step plate or the rider gets off the step plate;

a first detection unit to detect a rotation angle of the step plate; and

a second detection unit to detect a load exerted on the step plate, wherein

the first control unit starts getting-off assist control in a state where the rotation of the step plate in the left/right direction is permitted; when determined that the step plate is in a roughly horizontal state based on the rotation angle of the step plate detected by the first detection unit, controls the restriction mechanism so that the rotation of the step plate in the left/right direction is restricted; and when determined that the rider has gotten off the step plate based on the load exerted on the step plate that is detected by the second detection unit, finishes the getting-off assist control in a state where the rotation of the step plate in the left/right direction is restricted, and

the first control unit starts getting-on assist control in the state where the rotation of the step plate in the left/right direction is restricted; when determined that the rider has gotten on the step plate based on the load exerted on the step plate that is detected by the second detection unit, controls the restriction mechanism so that the rotation of the step plate in the left/right direction is permitted; and finishes the getting-on assist control in a state where the rotation of the step plate in the left/right direction is permitted.