Adaptive brake mode selection

An autonomous vehicle, comprising:

• a monitor system configured to measure vehicle states of the autonomous vehicle,
• a control system in communication with the monitor system to receive the measured vehicle states, the control system including a processor that is configured to:
• determine, using an adaptive model of the autonomous vehicle that adaptively adjusts model parameters while the autonomous vehicle is in operation, an available engine brake torque for reducing a current speed of the autonomous vehicle to a lower speed;
• and
• select a brake mode corresponding to the available engine brake torque and a rate of speed reduction,
• wherein, in case that the rate of speed reduction is equal to or smaller than a threshold, the brake mode is an engine brake in which engine exhaust valve opening is adjusted to generate a brake torque for reducing the current speed, the threshold determined in part based on the available engine brake torque, and
• wherein the brake mode includes a combination of the engine brake and a foundation brake in case the rate of speed reduction is greater than the threshold.

A non-transitory computer readable storage medium, storing computer readable instructions configured to perform a method that comprises:

• determining, using an adaptive model of the autonomous vehicle that adaptively adjusts model parameters while the autonomous vehicle is in operation, an available engine brake torque for reducing a current speed of the autonomous vehicle to a lower speed;
• and
• selecting a brake mode corresponding to the available engine brake torque and a rate of speed reduction,
• wherein, in case that the rate of speed reduction is equal to or smaller than a threshold, the brake mode is an engine brake in which engine exhaust valve opening is adjusted to generate a brake torque for reducing the current speed, the threshold determined in part based on the available engine brake torque, and
• wherein the brake mode is a combination of the engine brake and a foundation brake in case the rate of speed reduction is greater than the threshold.