To allow motors for right and left wheels to be driven at the same speed regardless of a difference in a running resistance of each wheel and thereby maintain the straight run of the vehicle, by employing a method for controlling wherein the speed of a motor of a higher speed is lowered down to the speed of a motor of a lower speed.

A speed difference compensator 15 converts a difference between the speeds detected by speed sensors 10, 11 to a pattern for correcting torque and then outputs the pattern. Equipment for judging the magnitude of a speed has a function to judge whether the speeds of a right and a left motor 6, 7 are large or small and a function to open and close the output of the speed difference compensator 15 based on the judgement. As for a method for controlling the vehicle, such a method is used that when there is a speed difference between the right and the left motor, for example, the motor of a higher speed is so controlled that the speed of the motor is lowered down to a lower speed of the other motor. To be more specific, the speed of the left motor 6 is higher than that of the right one 7, the equipment for judging the magnitude of a speed 16-1 outputs a signal to close a switching function 16-1a. After closing the switch function 16-1a, the output of the speed difference compensator 15 is inputted into an adder 14 to control an inverter 5 to correct the speed of the left motor 6 to the speed of the motor of a lower speed, thereby eliminating a speed difference and keeping straight the vehicle running.