US 5,704,446 A · Electric power steering control

Abstract

An electric power steering control apparatus comprising a vehicle steering wheel, a torque sensor for sensing torque in the vehicle steering column, a motor for providing motive force power assist to the steering system, a controller receiving the torque sensor signal and providing a motor control command to the motor responsive thereto, wherein the motor provides the motive force power assist responsive to the motor control command, and a high pass/low pass filter in the controller, wherein the high pass/low pass filter isolates low frequency components of the sensed vehicle steering system torque representing operator input torque and wherein the controller, responsive to the low frequency components determines a first, driver responsive, component of the motor control command, wherein the high pass/low pass filter isolates high frequency components of the sensed vehicle steering system torque and wherein the controller, responsive to the high frequency components, determines a second component of the motor control command.

Claims8

Dependent claims

An electric power steering control apparatus comprising:

a vehicle steering wheel;
a torque sensor for sensing torque in the vehicle steering system;
a motor for providing motive force power assist to the steering system;
a controller receiving the torque sensor signal and providing a motor control command to the motor responsive thereto, wherein the motor provides the motive force power assist responsive to the motor control command;
and
a high pass/low pass filter in the controller, wherein the high pass/low pass filter isolates low frequency components of the sensed vehicle steering system torque primarily representing operator input torque and wherein the controller, responsive to the low frequency components determines a first, driver responsive, component of the motor control command, wherein the high pass/low pass filer isolates high frequency components of the sensed vehicle steering system torque responsive to a high frequency gain, wherein the high frequency gain is responsive to the low frequency components, and wherein the controller, responsive to the high frequency components, determines a second component of the motor control command that maintains closed loop control over an entire range of driver inputs.

3 more elements

An electric power steering control system comprising:

a steering torque sensor providing a steering torque signal;
a high pass/low pass filter responsive to the steering torque signal and isolating high and low frequency components of the steering torque signal;
a driver-responsive command generator, responsive to the low frequency component of the steering torque signal and a first variable gain, and outputting a driver responsive motor command, wherein the first variable gain varies according to an instantaneous value of the low frequency component of the steering torque signal;
a gain scheduler, responsive to one of the low frequency component of the steering torque sensor and the first variable gain, outputting a second variable gain;
a high frequency responsive command generator, responsive to the high frequency component of the steering torque signal and the second variable gain, outputting a high frequency responsive motor command;
a command summer, summing the driver responsive and high frequency responsive motor commands to determine a power assist motor command;
and
an electric motor controlled responsive to the power assist motor command, wherein the electric motor responsively provides assist torque to the power steering system, wherein the electric power steering control maintains closed loop gains when an operator input steering torque is low or zero.

5 more elements

Dependencies are inferred from the claim text.

Electric power steering control

Life of this patent

Electric power steering control

Life of this patent

Abstract

Claims8