Vehicle steering control system

A vehicle steering control system for a vehicle equipped with steerable wheels that are power driven, comprising:

• manual steering torque input means for manually applying a manual steering torque to said steerable wheels;
• powered steering actuator means for applying an actuating steering torque to said steerable wheels;
• means for detecting a lateral dynamic condition of the vehicle;
• drive force computing means for computing a drive force of said power driven steerable wheels;
• control means for determining a steering reaction torque that is to be added to said actuating steering torque produced by said powered steering actuator means, according to said detected lateral dynamic condition of the vehicle;
• and
• modifying means for modifying said steering reaction torque that is determined by said control means according to said drive force computed by said drive force computing means,
• whereby a torque steer produced in said vehicle by said drive force of said power driven steerable wheels is controlled by said steering reaction torque which is determined by said control means and modified by said modifying means, and
• said modifying means maintains said steering reaction torque determined by said control means substantially unchanged when said drive force is relative small, and amplifies said steering reaction torque determined by said control means when said drive force is relatively great.

A vehicle steering control system for a vehicle equipped with steerable wheels that are power driven, comprising:

• manual steering torque input means for manually applying a manual steering torque to said steerable wheels;
• powered steering actuator means for applying an actuating steering torque to said steerable wheels;
• means for detecting a lateral dynamic condition of the vehicle;
• drive force computing means for computing a drive force of said power driven steerable wheels;
• control means for determining a steering reaction torque that is to be added to said actuating steering torque produced by said powered steering actuator means, according to said detected lateral dynamic condition of the vehicle;
• and
• modifying means for modifying said steering reaction torque that is determined by said control means according to said drive force computed by said drive force computing means,
• whereby a torque steer produced in said vehicle by said drive force of said power driven steerable wheels is controlled by said steering reaction torque which is determined by said control means and modified by said modifying means, and
• said modifying means maintains said steering reaction torque determined by said control means substantially unchanged when said drive force is below a predetermined value, and amplifies said steering reaction torque determined by said control means when said drive force is at least as great as said predetermined value.

A vehicle steering control system for a vehicle equipped with steerable wheels that are power driven, comprising:

• manual steering torque input means for manually applying a manual steering torque to said steerable wheels;
• powered steering actuator means for applying an actuating steering torque to said steerable wheels;
• means for detecting a lateral dynamic condition of the vehicle;
• drive force computing means for computing a drive force of said power driven steerable wheels;
• control means for determining a steering reaction torque that is to be added to said actuating torque produced by said powered steering actuator means, according to said detected lateral dynamic condition;
• and
• modifying means for modifying said steering reaction torque that is determined by said control means according to said drive force computed by said drive force computing means so that the modified steering reaction torque controls torque steer of the vehicle.