Control Strategy for Roll Control

hi, i want to know the control algorithm assumptions to be considered while designing a body roll control strategy for an automobile during cornering. i referred to the Active Cornering Enhancement of Land Rover Discovery but was not able to figure out the control algorithm with 2 accelerometers. is there anyone who can help me on this subject? i am doing this exercise related to Roll Angle Reduction for SUVs (Sport Utility Vehicles). if anyone can provide insight into this with vehicle dynamics related issues as well then it will of great help.

Reply to
gophane.harsh
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Dear gophane.harsh:

First blush: where in the structure are the two accelerometers located?

google has 5 hits, some of which are to literature citations, with algorithm "roll angle reduction"

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should whet your appetite.

David A. Smith

Reply to
N:dlzc D:aol T:com (dlzc)

hey, i was talking about the two accelerometers used by the rover engineers in the land rover discovery's ACE (active cornering enhancement) system to detect the body roll and related algorithm incorporated into the controller.

Reply to
gophane.harsh

hi there, is anybody aware of control circuitry to be implemented into the roll control controller for a passenger vehicle?

Reply to
gophane.harsh

Look for articles in Proceedings of SAE Conferences on Vehicular Stability.

There are many roll handling approaches, both on the sensing side and on the actuation side. Here is a small sample: Types of roll: 'Trip' roll happens when tires/rims get into soft material on roadway shoulder, with some component of vehicle motion perpendicular to vehicle axis. Tires/rims dig into soft material, thereby tripping the vehicle in to a roll. A high percentage of SUV rolls are trip type. Aggravated by high steering angle. 'Longitudinal' roll happens less often, has roll axis more or less in line with vehicle direction of travel. Much more common on big rigs than SUVs. Cornering forces and gravitational forces (unfavorable roadway camber) act on center of mass to lift vehicle off of tires on one side. Once COM is over outside wheels, roll is almost inevitable. Aggravated by soft suspension, tires, many other factors.

Sensing: Trip roll is often preceded by high steering angle and rapid vehicle yaw. Yaw sensing involves special accelerometer combinations. Steering angle is a simple encoder. Some systems monitor suspension forces, e.g., spring loads, and angles, e.g., axle relative to body.

Actuation: Various systems process sensor inputs and do things like stiffen suspension, increase force required to turn steering wheel, apply brakes (this simultaneously slows vehicle and makes it more difficult to oversteer)

This will give you a taste. Have fun doing more thorough research.

Paul Mathews

Reply to
Paul Mathews

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