A sprung mass damping control system of a vehicle, which aims to suppress sprung mass vibration generated in a vehicle body of a vehicle provided with at least a motor-generator (first and second motor-generators (31, 32)) as a drive source, includes a sprung mass damping control amount calculating device (5) that sets a sprung mass damping control amount for suppressing the sprung mass vibration, and a drive source control device (a motor-generator control device (6)) that executes sprung mass damping control by controlling a motor-generator control amount of the motor-generator to realize the sprung mass damping control amount.

Sprung mass damping control system of vehicle

A steering system ( 10 ) and method ( 70 ) for controlling the steering of a vehicle having a steering wheel ( 12 ), a steering column ( 14 ) connected to said steering wheel ( 12 ), and an electric motor ( 20 ) operatively engaged with the steering column ( 14 ) for supplying torque assist. A steering angle sensor ( 32 ) is employed for sensing an angular position θ c of the steering wheel ( 12 ). The system has a torque estimator ( 40 ) for determining an estimated torque signal (T d est) as a function of the measured steering wheel angle, and a motor controller ( 30 ) for generating a motor control signal (U) as a function of said estimated torque. Accordingly, the present invention reduces the complexity and cost of the electric power assist steering system by eliminating the need for a conventional pinion torque sensor, without sacrificing vehicle steering performance.

Vehicle electric power assist steering system and method using angle based torque estimation

A steering system ( 10 ) and method ( 70 ) for controlling the steering of a vehicle having a steering assembly including a steering wheel ( 12 ), a steering column ( 14 ) connected to said steering wheel ( 12 ), and an electric motor ( 20 ) operatively engaged with the steering assembly for supplying torque assist. A steering angle sensor ( 32 ) is employed for sensing an angular position θ c of the steering column ( 14 ). The system has a torque estimator ( 40 ) for determining an estimated torque signal (T d est), and an H-infinity controller ( 64 ) coupled in a feedback path ( 44 ) for generating a feedback signal which is combined with a feedforward signal to generate a motor control signal (U) as a function of the estimated torque. Accordingly, the present invention provides a stable and robust control system, without sacrificing steering performance and desired steering feel.

Vehicle electric power assist steering system and method using H-infinity control

A steering system ( 10 ) and method ( 70 ) for controlling the steering of a vehicle having a steering assembly including a steering wheel ( 12 ), a steering column ( 14 ) connected to said steering wheel ( 12 ), and an electric motor ( 20 ) operatively engaged with the steering assembly for supplying torque assist. A steering angle sensor ( 32 ) is employed for sensing an angular position θ c of the steering column ( 14 ). The steering system has first and second H-infinity controllers ( 64 A and 64 B) coupled in a feedback path ( 44 ) for generating first and second feedback signals as a function of the driver torque and first and second characteristics (J C and K C ) of the steering system. One of the first and second feedback signals is selected and the selected feedback signal is combined with a feedforward signal to generate a motor control signal (U) as a function of the estimated torque.

H-infinity control and gain scheduling method for electric power assist steering system

A power steering apparatus for use in association with an electric motor, includes a switch circuit driven by a PWM wave signal which switches between one polarity and the other of the voltage developed across a motor-driving current detecting resistance synchronously with the PWM wave signal so as to detect the magnitude and direction of the motor-driving current, thereby controlling a duty cycle of the PWM wave signal in accordance with the detected motor-driving current. Thus, the motor steering touch and feeling is enhanced.

Power steering apparatus for performing feedback control of motor-driving current

A power steering system having an electric motor and including an input shaft fixed to a steering wheel, an output shaft coupled to the motor via a reduction gear, and a torsion bar provided between the input and output shafts, the output shaft being rotatable by the resultant of a manual torque for rotating the wheel and the torque of the motor. The system comprises a sensor for detecting the relative angular displacement between the input shaft and the output shaft, and a microcomputer having stored therein the relationship between the relative angular displacement and the motor current target value for determining the direction of rotation of the motor and a motor current target value from the output of the sensor to produce outputs. The relationship stored in the microcomputer is a nonlinear relationship wherein variations in the motor current target value with the relative angular displacement are small in the range of small relative angular displacements but are great in the range of great displacements.

Shigeo Nishimura

Papers

Power steering system incorporating electric motor