Method and system for detecting steering wheel contact

Abstract

In accordance with various exemplary embodiments, the present disclosure describes a method and system for detecting a state of hand/steering wheel contact. In one exemplary embodiment, a test signal is generated and a torque in accordance with the test signal is applied to a power-assisted steering system and the resultant steering wheel torque signal is measured. The test signal and the measured steering wheel torque signal are supplied, as measurement variables, to a manager. The manager models a steering wheel/hand system and modifies the modeled steering wheel/hand system using differences between the measurement variables and the modeled steering wheel/hand system.

What is claimed is: 
     
         1 . A method for detecting a state of steering wheel contact, comprising:
 generating a test signal;   applying torque in accordance with the test signal to a power-assisted steering system by an electric servomotor of the power-assisted steering system;   measuring steering wheel torque;   supplying the test signal and the measured steering wheel torque signal as measurement variables to a manager, the manager being configured to model a steering wheel system and to detect steering wheel contact using differences between the measurement variables and the modeled steering wheel system; and   outputting a status variable of the modeled steering wheel system, the status variable comprising the state of the steering wheel contact.   
     
     
         2 . The method as claimed in  claim 1 , in which the manager applies a spectral transformation or a statistical filter method to the measurement variables, or contains a neural network. 
     
     
         3 . The method as claimed in  claim 1 , wherein the vehicle measurement signals are also supplied to the manager as measurement variables. 
     
     
         4 . The method as claimed in  claim 1 , wherein the measurement variables are stored by the manager. 
     
     
         5 . The method as claimed in  claim 1 , wherein the test signal is generated and torque is applied to the power-assisted steering system based on a triggering signal. 
     
     
         6 . The method as claimed in  claim 1 , wherein the torque applied to the power-assisted steering system has an amplitude which is selected such that a change in a steering wheel angle during operation of a vehicle remains smaller than a threshold angle. 
     
     
         7 . The method as claimed in  claim 1 , wherein the generation of the test signal and the torque applied to the power-assisted steering system are terminated after a predetermined period of time has elapsed. 
     
     
         8 . A system for detecting a state of steering wheel contact, comprising:
 a power-assisted steering system, comprising:
 an electric servomotor, 
 a torque sensor, and 
 a steering wheel, wherein a test torque is applied to the steering wheel based on receipt of a test signal; and 
   a control unit configured to:
 receive and store vehicle measurement signals as measurement variables; 
 model a steering wheel system based on the measurement variables, 
 predict the power-assisted steering system response to the test torque based on the model, and 
 detect steering wheel contact using differences between the predicted response and an actual response of the power-assisted steering system.