RE: Electric-Motor-Control Trying to understand Electric Power Steering
Toma Dordea
apply a force on the steering wheel. This translates into torque, which
is basically the product between applied force and the diameter of the
steering wheel.
An electric motor runs along a characteristic curve represented by the
product of torque and speed. This product represents the (output, shaft)
power of the motor. So, at a given level of power (rated, nominal, etc)
when increasing the speed, the torque decreases.
So to ease turning the steering wheel by hand, the motor adds torque,
which basically translates into a lower force required to be applied by
the driver to turn the wheels.
Toma P. Dordea, PE
ALFATECH CAMBRIDGE GROUP
97 East Brokaw Road, Suite 300
San Jose, CA 95112
Tel.408.487.1200 Fax.408.436.1511
Dir.408.487.1258 Cel.925.980.2435
mailto: toma....@atcginc.net
http:///www.atcginc.net
-----Original Message-----
From: Electric-Mo...@googlegroups.com
[mailto:Electric-Mo...@googlegroups.com] On Behalf Of Vaiti
Sent: Thursday, January 11, 2007 6:03 AM
To: Electric Motor Control
Subject: Electric-Motor-Control Trying to understand Electric Power
Steering
I am trying to understand how electric assisted power steering works.
The basic principle is that the wheel has to turn more than what is
applied on the steering wheel using a electric motor(basically to give
the driver a better feeling about the vehicle). As far as i have read,
torque is controlled to do this.
My doubt is why not speed ? Why not control speed to achieve this ? Why
can't motor running at more speed create more force ?
The question may be basic but will help my understanding of the system.
Thanks.
