Vehicle electric power assist steering system and method using velocity based torque estimation
First Claim
1. An electric power assisted steering system for a vehicle, comprising:
- a steering assembly including a steering wheel connected to a steering column;
an electric motor operatively engaged with said steering assembly for supplying steering torque assist;
a velocity detector detecting an angular velocity of said electric motor;
a torque estimator calculating an estimated driver torque applied to the steering wheel by a driver as a function of said detected angular velocity; and
a controller generating a motor control signal as a function of said estimated torque for controlling the electric motor.
1 Assignment
0 Petitions
Accused Products
Abstract
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 the steering wheel (12), and an electric motor (20) operatively engaged with the steering column (14) for supplying torque assist. A velocity detector is employed for detecting an angular velocity {dot over (θ)}m of the electric motor (20). The system has a torque estimator (40) for determining an estimated torque signal Tdest as a function of the detected motor velocity {dot over (θ)}m, and a motor controller (30) for generating a motor control signal (U) as a function of the 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.
-
Citations
17 Claims
-
1. An electric power assisted steering system for a vehicle, comprising:
-
a steering assembly including a steering wheel connected to a steering column;
an electric motor operatively engaged with said steering assembly for supplying steering torque assist;
a velocity detector detecting an angular velocity of said electric motor;
a torque estimator calculating an estimated driver torque applied to the steering wheel by a driver as a function of said detected angular velocity; and
a controller generating a motor control signal as a function of said estimated torque for controlling the electric motor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A control system for controlling electric motor torque assist to an electric power assisted steering system for a vehicle having a steering assembly including a steering wheel connected to a steering column and an electric motor operatively engaged with the steering assembly for supplying steering torque assist, wherein said control system comprises:
-
a velocity detector detecting an angular velocity of the electric motor;
a torque estimator estimating a driver torque applied to the steering wheel by a driver as a function of said sensed angular velocity of the electric motor; and
a controller generating a motor control signal as a function of said estimated torque for controlling the electric motor. - View Dependent Claims (12)
-
- 10. The control system as defined in aim 9, wherein said torque estimator determines said estimated torque signal further as a function of the motor control signal input to the electric motor.
-
13. A method of controlling an electric power assisted steering system having a steering assembly including a steering wheel connected to a steering column for a vehicle and an electric motor operatively coupled to the steering assembly, said method comprising the steps of:
-
sensing an angular velocity of the electric motor;
estimating a driver torque applied to the steering wheel by a driver as a function of said sensed angular velocity of the electric motor;
generating a motor control signal as a function of said estimated torque for controlling an electric motor; and
applying said motor control signal to an electric motor to generate a controlled amount of steering torque assist. - View Dependent Claims (14, 15, 16, 17)
-
Specification