Zf Lenksysteme Gmbh

Michael Bischofberger

Arnulf Heilig

Stephan Hiegler

Dietmar Hiller

A method for controlling an electrical power steering system for a vehicle includes an electrical servomotor, a steering device for entering a reference value (&#x3b8;) of a steering angle into a control andlor regulation device, a moment sensor and an angle sensor for the steering device, a device for estimating the moment (M) at the steering device and an angle sensor for determining the angle (&#x3b8;) of a power take-off of the electrical servomotor. In order to control the electrical power steering system, which makes a non-critical behavior possible in the event of a malfunction or failure of a moment sensor at the steering device, provisions are made so that an offset value (&#x394;) is constantly formed from the reference value (&#x3b4;) of the steering angle and the actual value &#x3b8;of the steering angle, and a virtual moment (M) of the steering device is determined on the basis of the offset value (&#x394;) and is used to control the electrical servomotor.

Method for controlling an electric power steering system

A vehicle power steering system suppresses chattering, i.e., unpleasant noises in the form of mechanical and generally higher frequency oscillations resulting from backlash in a gear connection transmitting the torque from the motor to the steering wheel mechanics, produced under certain driving conditions. A control system is provided which evaluates the rotor rpm of the electric motor, and increases the dynamic response time of the rotor in the event that the evaluation of the rotor rpm indicates an unstable state of the control system. As a result, chattering is suppressed only when a critical driving situation arises in which the control system becomes unstable, while, in the normal state, the steering system exhibits all properties thereof, and is neither delayed nor limited in a dynamic behavior thereof.

Motor control in vehicle power steering system

A method is for compensating for a rotor angle deviation of a motor, which may be used as an actuator, e.g., as a servo actuator, in a steering system. The rotor angle deviation is compensated for by a piecewise linearized control of the difference between a desired rotor angle, which is based on a manual torque and a stored rotor angle, and a measured rotor angle, a control factor of the control being variable as a function of the control range.

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Schwaebisch Gmuend, Germany

Michael Bischofberger