Abstract: An electronic control unit determines that a vehicle is traveling in a straight line if a state in which the steering torque is less than a predetermined steering torque and an amount of change in the steering angle is less than a predetermined steering angle continues for a predetermined period of time when the vehicle speed is greater than a predetermined vehicle speed. Also, if the steering angle of the steering wheel is not 0, while the vehicle is traveling in a straight line, the electronic control unit calculates the steering amount of rear wheels that matches the steering amount of front wheels, using the steering angle of the steering wheel. Then the electronic control unit steers the rear wheels by driving an electric motor until a controlled neutral steering position of the rear wheels that corresponds to the steering amount matches an absolute neutral steering position.

Abstract: A sensor (3, 4) is assigned to a mechanically adjustable part (e.g. 1) and generates sensor signals corresponding to the positions of the part. An initial range (sr) of the sensor values (s) is assigned to an inoperative position of the part and covers the varying initial positions of the part (e.g. 1). An evaluation device (9) stores a longer constant signal in the initial range as an intermediate value (st). A longer constant sensor signal is compared with the intermediate value (st) after the initial range (sr) is exceeded and after the subsequent return into this range. If it is established that both values are approximately of the same magnitude, the evaluation device stores this value as an initial value (sp, spn). As a result, the inoperative position of the part is reliably verified without the use of additional auxiliary means.

Abstract: A power steering device for a vehicle includes: a wheel-steering generator adapted to be connected to an axle case comprising a differential gear and a pair of right and left axles having a common axis; right and left steering knuckles adapted to be connected to the right and left axles, respectively, to attach right and left steering wheels thereto; right and left tie rods disposed between the right steering knuckle and the right piston rod and between the left steering knuckle and the left piston rod, respectively, to transmit force from the right and left piston rods to the respective steering knuckles, thereby steering the respective wheels; and right and left coupling members which couple the right and left tie rods with the right and left piston rods, respectively.