An electric vehicle, including a structure mounted on balls which are arranged for rolling on the ground, wherein each ball is freely rotatably supported by a ball-supporting member about any axis passing through the centre of the ball, wherein an actuating roller is associated with each ball , which is in friction contact with and above the ball and which is rotatably supported about its axis by a roller-supporting structure , wherein said roller-supporting structure is, in turn, rotatably mounted about a substantially vertical axis within a main supporting structure which is rigidly connected to said ball-supporting member , wherein said main supporting structure carries a first electric motor for driving the rotation of said roller-supporting structure about said substantially vertical axis , and wherein said roller-supporting structure carries a second electric motor for driving the rotation of the roller about its axis , so that when the second electric motor is actuated, said roller causes, by friction, rotation of the ball about an axis passing through the centre thereof and parallel to the axis of the roller , whereas when said first electric motor is actuated, said roller is oriented about said vertical axis , so as to vary the rolling direction of the ball , said electric vehicle being characterized in that : - the vehicle is a motorized chair, with a seat carried by said structure , - said structure is provided with three articulated legs , each having a lower end with which a respective ball is associated, - said main supporting structure which is associated with each ball , and which rotatably supports said roller-supporting structure about a substantially vertical axis , is pivotally supported about a horizontal axis by the lower end of the respective articulated leg . wherein each ball is freely rotatably supported by a ball-supporting member about any axis passing through the centre of the ball, wherein an actuating roller is associated with each ball , which is in friction contact with and above the ball and which is rotatably supported about its axis by a roller-supporting structure , wherein said roller-supporting structure is, in turn, rotatably mounted about a substantially vertical axis within a main supporting structure which is rigidly connected to said ball-supporting member , wherein said main supporting structure carries a first electric motor for driving the rotation of said roller-supporting structure about said substantially vertical axis , and wherein said roller-supporting structure carries a second electric motor for driving the rotation of the roller about its axis , so that when the second electric motor is actuated, said roller causes, by friction, rotation of the ball about an axis passing through the centre thereof and parallel to the axis of the roller , whereas when said first electric motor is actuated, said roller is oriented about said vertical axis , so as to vary the rolling direction of the ball , said electric vehicle being characterized in that : - the vehicle is a motorized chair, with a seat carried by said structure , - said structure is provided with three articulated legs , each having a lower end with which a respective ball is associated, - said main supporting structure which is associated with each ball , and which rotatably supports said roller-supporting structure about a substantially vertical axis , is pivotally supported about a horizontal axis by the lower end of the respective articulated leg . - the vehicle is a motorized chair, with a seat carried by said structure , - said structure is provided with three articulated legs , each having a lower end with which a respective ball is associated, - said main supporting structure which is associated with each ball , and which rotatably supports said roller-supporting structure about a substantially vertical axis , is pivotally supported about a horizontal axis by the lower end of the respective articulated leg . <EOS>