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This paper presents an optimal control strategy for assigning wheel slips on all of the wheels of a tractor/trailer combination. Most ABS controllers work on a wheel by wheel or an axle by axle basis without consideration for overall system stability. This controller is based on a linear program (LP) and assigns wheel slips for each wheel in accordance with one of the following criteria: 1) During an emergency braking maneuver, optimal wheel slips are determined which maximize stopping while constraining the system to be stable, or 2) During a nonemergency braking maneuver, the controller is used to maximize stability while maintaining an achievable (commanded) deceleration. Computer simulations, which modeled a full tanker truck, were run to compare the response of the proposed controller with two controllers which incorporated select-low control and individual control ABS systems on various axles.

This paper studies the performance benefits attainable by application of an advanced brake controller. This brake controller is optimal in the sense that it determines the wheel slips that provide the maximum level of deceleration while maintaining a specified level of directional stability. It determines target wheel slips for each wheel individually. The performance of the controller is compared to the performance of a more restricted controller that determines only one target wheel slip for the front tires and only one target wheel slip for the rear tires.

A set of rules is derived that can be used to determine effective choices for the wheel slips to be maintained at the wheels of a vehicle that has the capability to control its wheel slip levels. The determined wheel slips will be effective at enhancing the stability of the vehicle.