Steering control system for vehicle

A steering control system for a wheeled vehicle, comprising:

• a steering means for steering said wheeled vehicle in response to a control signal representing a control steering input;
• a sensing means for sensing an actual vehicle motion variable of said vehicle;
• and
• a controlling means for determining an estimated vehicle motion variable corresponding to said control steering input by using a predetermined estimator transfer characteristic which is a transfer characteristic relating a vehicle steering response to a steering input, producing a deviation signal representing a deviation of said actual vehicle motion variable from said estimated vehicle motion variable, and further producing said control signal in accordance with said deviation signal so as to reduce said deviation by using a predetermined compensator transfer characteristic which is a transfer characteristic relating the steering input to the vehicle steering response, and a predetermined filter transfer characteristic,
• wherein said steering means comprises a primary steering means for steering said wheeled vehicle by varying an actual front wheel steer angle of said wheeled vehicle in accordance with a driver's steering command, and an auxiliary steering means for steering said wheeled vehicle in response to said control signal, said sensing means comprises a vehicle motion sensing means for sensing said actual vehicle motion variable of said wheeled vehicle, and said control system further comprises a commanding means for producing a steering command signal representing the driver's steering command, and
• wherein said controlling means comprises an estimating means for receiving said steering command signal and said control signal, determining a first estimated vehicle output resulting from said steering command by using a first estimator transfer characteristic for determining the vehicle steering response from the steering input, further determining a second estimated vehicle output resulting from said control input by using a second estimator transfer characteristic for determining the vehicle steering response from the steering input, and further determining said estimated vehicle motion variable which is a sum of said first and second estimated vehicle outputs.

A steering control system for a wheeled vehicle, comprising:

• a steering means for steering said wheeled vehicle in response to a control signal representing a control steering input;
• a sensing means for sensing an actual vehicle motion variable of said vehicle;
• and
• a controlling means for determining an estimated vehicle motion variable corresponding to said control steering input by using a predetermined estimator transfer characteristic which is a transfer characteristic relating a vehicle steering response to a steering input, producing a deviation signal representing a deviation of said actual vehicle motion variable from said estimated vehicle motion variable, and further producing said control signal in accordance with said deviation signal so as to reduce said deviation by using a predetermined compensator transfer characteristic which is a transfer characteristic relating the steering input to the vehicle steering response, and a predetermined filter transfer characteristic,
• wherein said control system further comprises a commanding means for producing a steering command signal representing a driver's steering command, and said controlling means comprises a first steering input determining means for a receiving said steering command signal and producing a first steering input signal in accordance with said steering command, and a second steering input determining means for determining a second steering input in accordance with said deviation so as to reduce said deviation by using said compensator transfer characteristic and said filter transfer characteristic, and producing a second steering input signal, and said steering means includes a means for steering said wheeled vehicle in accordance with said first and second steering input signals.

A steering control system for a wheeled vehicle, comprising:

• a steering means for steering said wheeled vehicle in response to a control signal representing a control steering input;
• a sensing means for sensing an actual vehicle motion variable of said vehicle;
• and
• a controlling means for determining an estimated vehicle motion variable corresponding to said control steering input by using a predetermined estimator transfer characteristic which is a transfer characteristic relating a vehicle steering response to a steering input, producing a deviation signal representing a deviation of said actual vehicle motion variable from said estimated vehicle motion variable, and further producing said control signal in accordance with said deviation signal so as to reduce said deviation by using a predetermined compensator transfer characteristic which is a transfer characteristic relating the steering input to the vehicle steering response, and a predetermined filter transfer characteristic,
• wherein said controlling means comprises a feedback compensating means for determining said control steering input by using said compensator transfer characteristic which is in an inverse form of said estimator transfer characteristic, and said filter transfer characteristic which has such a characteristic that a steady state gain is equal to one, and a difference resulting from subtraction of an order of a numerator of said filter transfer characteristic from an order of a denominator of said filter transfer characteristic is equal to or higher than a difference resulting from subtraction of an order of a numerator of said estimator transfer characteristic from an order of a denominator of said estimator transfer characteristic.