Development of a controller to perform an automatic lateral emergency collision avoidance manoeuvre for a passenger car

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An automatic controller is being developed to cause a passenger car to perform a lateral emergency collision avoidance manoeuvre: a single lane change at high speed, while operating at the vehicle's physical limits. The car is stabilised about a predetermined velocity profile by a feedforward steering action based on the Ackermann steering angle, combined with a feedback control loop which uses the anti-lock braking system to apply differential torques to each of the wheels. The forces to be applied to each wheel are calculated using the pseudo-inverse of a velocity-based linearisation of a system model. This inverse controller acts upon a signal containing the lateral and yaw veloc-ity error, fed back through a scheduled gain matrix; the matrix, obtained by pole placement and scheduled according to the vehicle state, causes the car to exhibit uniform dynamic behaviour as its speed increases. An additional control loop augments the steering angle of the front wheels, using actuators which form part of a steer-by-wire system, to correct for errors in the lateral position and heading angle for which the force/velocity control loop does not account. The control system is evaluated in simulation experiments which show that the performance requirements are met over a wide range of velocities.

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