Vehicle and method for suspension spring degradation detection and fault tolerant tire force estimation

A method of controlling an active aerodynamic system of a vehicle, the method comprising:

• sensing at least one vehicle handling characteristic during operation of the vehicle with the active aerodynamic system disengaged, with a vehicle mounted sensor, wherein the at least one handling characteristic of the vehicle includes at least one of an acceleration rate of the vehicle along an X axis of the vehicle, an acceleration rate of the vehicle along a Y axis of the vehicle, an acceleration rate of the vehicle along a Z axis of the vehicle, a roll rate of the vehicle, a pitch rate of the vehicle, or a vertical acceleration rate of at least one wheel of the vehicle;
• calculating a first spring force estimated value from the at least one vehicle handling characteristic, with a computing device;
• calculating a second spring force estimated value from a nominal spring characteristic curve, with the computing device;
• comparing a difference between the first spring force estimated value and the second spring force estimated value to a spring threshold value, to determine if the difference is less than the spring threshold value or if the difference is equal to or greater than the spring threshold value;
• engaging and controlling the active aerodynamic system with the computing device, using the nominal spring characteristic curve, when the difference between the first spring force estimated value and the second spring force estimated value is less than the spring threshold value;
• adjusting the nominal spring characteristic curve to define an adjusted spring characteristic curve, with the computing device, when the difference between the first spring force estimated value and the second spring force estimated value is equal to or greater than the spring threshold value;
• and
• engaging and controlling the active aerodynamic system with the computing device, using the adjusted spring characteristic curve, when the difference between the first spring force estimated value and the second spring force estimated value is equal to or greater than the spring threshold value.

A vehicle comprising:

• an active aerodynamic system engageable to adjust aerodynamic downforce on the vehicle;
• a suspension system having a spring supporting a wheel;
• at least one sensor operable to sense at least one vehicle handling characteristic of the vehicle, wherein the at least one handling characteristic of the vehicle includes at least one of an acceleration rate of the vehicle along an X axis of the vehicle, an acceleration rate of the vehicle along a Y axis of the vehicle, an acceleration rate of the vehicle along a Z axis of the vehicle, a roll rate of the vehicle, a pitch rate of the vehicle, or a vertical acceleration rate of at least one wheel of the vehicle;
• a computing device in communication with the active aerodynamic system and the at least one sensor, wherein the computing device includes a processor and a memory having suspension diagnostic and control algorithm stored therein, and wherein the processor is operable to execute the suspension diagnostic and control algorithm to:
• sense at least one vehicle handling characteristic during operation of the vehicle with the active aerodynamic system disengaged;
• calculate a first spring force estimated value from the at least one vehicle handling characteristic;
• calculate a second spring force estimated value from a nominal spring characteristic curve stored in the memory of the computing device;
• calculate a difference between the first spring force estimated value and the second spring force estimated value;
• compare the difference to a spring threshold value to determine if the difference is less than the spring threshold value or if the difference is equal to or greater than the spring threshold value;
• and
• activate a signal to provide a service recommendation when the difference is equal to or greater than the spring threshold value.