Patent 7703568 was granted and assigned to Toyota on April, 2010 by the United States Patent and Trademark Office.
In a coaxial two-wheeled vehicle, an attitude controller (84) calculates motor torque Tgyr for maintaining a base so that it has a target angle from deviation between base angle command θref serving as attitude command and current base angle θ0 calculated by using a gyro sensor (13) and an acceleration sensor (14). On the other hand, at a position proportional controller (86R), a differentiator (88R) and a velocity proportional controller (89R), there is performed PD control with respect to deviation between rotation position command Prefr of a motor rotor (92R) for right wheel and current rotation position θr of a motor rotor (92R). A current control amplifier (91R) generates motor current on the basis of added value of motor torque which is the control result and estimated load torque T1 calculated by using pressure sensors to drive the motor rotor (92R).