Active steering for handling/stability enhancement

Abstract

A control system for a steering system in a vehicle comprising: a reference model responsive to an operator input that computes desired states of the vehicle; a feedforward controller in operable communication with the reference model. The feedforward controller computes a first control value based on input from said reference model and based on at least one of: a lateral velocity, a rate of lateral velocity, a lateral acceleration, and a combination, wherein the combination includes a yaw rate with at least one of a lateral velocity, a rate of lateral velocity, and a lateral acceleration of the motor vehicle. The system also includes an actuator for affecting the steering system based on the first control value, the actuator in operable communication with the feedforward controller.

1 . A control system for a steering system in a vehicle comprising: 
 a reference model responsive to an operator input and tire relaxation, which computes desired states of the vehicle;    a feedforward controller in operable communication with said reference model, said feedforward controller computes a first control value based on input from said reference model and based on at least one of: a lateral velocity, a rate of lateral velocity, a lateral acceleration, and a combination, wherein said combination includes a yaw rate with at least one of a lateral velocity, a rate of lateral velocity, and a lateral acceleration of said motor vehicle;    an actuator for affecting the vehicle based on said first control value, said actuator in operable communication with said feedforward controller;    a state estimator that estimates an actual state of said vehicle; and    a feedback controller that computes a second control value by comparing said estimate of actual state with a desired state, wherein said feedback controller computes a blended solution for said second control value based on a vehicle velocity and wherein said second control value is based on said yaw rate if a vehicle velocity is below a selected threshold; and    wherein said second control value is based on said at least one of a lateral velocity, a rate of lateral velocity, and a lateral acceleration of said vehicle if said vehicle velocity is above a selected threshold; otherwise    said second control value is based on a combination of said yaw rate, said at least one of a lateral velocity, a rate of lateral velocity, and a lateral acceleration of said vehicle.    
   
   
       2 . The control system of  claim 1  further comprising a state estimator, said state estimator estimates an actual state of said vehicle.  
   
   
       3 . The control system of  claim 2  further comprising a feedback controller, said feedback controller computes a second control value by comparing said estimate of actual state with a desired state.  
   
   
       4 . The control system of  claim 3  wherein said feedback controller computes a blended solution for said second control value based on a vehicle velocity.  
   
   
       5 . The control system of  claim 3  wherein: 
 said second control value is based on said yaw rate if a vehicle velocity is below a selected threshold;    said second control value is based on said at least one of a lateral velocity, a rate of lateral velocity, and a lateral acceleration of said vehicle if said vehicle velocity is above a selected threshold; otherwise    said second control value is based on a combination of said yaw rate said at least one of a lateral velocity, a rate of lateral velocity, and a lateral acceleration of said vehicle.    
   
   
       6 . A control system for a steering system in a vehicle comprising: 
 a reference model responsive to an operator input and tire relaxation, which computes desired states of the vehicle;    a feedforward controller in operable communication with said reference model, said feedforward controller computes a first control value based on input from said reference model and based on at least one of: a lateral velocity, a rate of lateral velocity, a lateral acceleration, and a combination, wherein said combination includes a yaw rate with at least one of a lateral velocity, a rate of lateral velocity, and a lateral acceleration of said motor vehicle;    an actuator for affecting the vehicle based on said first control value, said actuator in operable communication with said feedforward controller;    wherein said reference model computes said desired state for the vehicle based on a magnitude of a lateral acceleration and at least one of a throttle command and a magnitude of a longitudinal accelerations;    wherein said desired state for the vehicle includes at least one of a desired yaw rate, a desired lateral velocity, a desired rate of lateral velocity, and a desired lateral acceleration for said vehicle; and    wherein said first control value is based on at least one of a vehicle speed, a steering wheel position, and vehicle tire dynamics.    
   
   
       7 . The control system of  claim 1  wherein said desired state for the vehicle includes at least one of a desired yaw rate, a desired lateral velocity, a desired rate of lateral velocity, and a desired lateral acceleration for said vehicle.  
   
   
       8 . The control system of  claim 1  wherein said first control value is based on at least one of a vehicle speed, a steering wheel position, and vehicle tire dynamics.