Device and method for trajectory-dependent vehicle control
A vehicle control system includes a lateral control device. The lateral control device includes: a lateral controller for performing lateral control of the vehicle defined by a set of control parameters, based on minimizing a difference in a control value between a reference trajectory curve and a current trajectory curve described by the vehicle; a maximum distance determination unit for projecting the determined road layout information up to a given distance in front of the vehicle, and for determining the maximum distance at which the polynomial function representing the road layout satisfies one or more control conditions based on projected road layout information; a limit checking unit for determining a stability envelope and for checking whether limits of the stability envelope are reached by the vehicle based on the determined maximum distance. The control adapter adapts the control parameters of the lateral controller if the limits are reached.
1 . A system for controlling a vehicle comprising a perception system that uses at least one trajectory sensor to determine a road layout, the road layout representing a trajectory to be followed by the vehicle, the system comprising a lateral control device that comprises:
a road detector configured to determine, for a current state of the vehicle, information items of the road layout ahead of the vehicle based on of information items provided by said perception system, the road layout being represented by a polynomial function having a given order;
a lateral controller configured to perform a lateral control of the vehicle, which is defined by a set of control parameters, based on of a minimization of a difference in a control value between a reference trajectory curve of the vehicle and a current trajectory curve being described by the vehicle, which corresponds to the current state of the vehicle including an e-horizon provided by the trajectory sensor, the e-horizon being a longest distance at which the trajectory sensor can operate;
a maximum distance determination unit configured to project the road layout information items that have been determined to a given distance ahead of the vehicle, and to determine the maximum distance at which said polynomial function satisfies one or more control conditions based on of the projected road layout information items; and
a limit verification unit configured to determine, for the current state of the vehicle, a stability envelope of the vehicle which is defined by limits corresponding to application conditions of a control adapter of the vehicle, and to verify whether said limits of the stability envelope have been reached by the vehicle based on of the maximum distance that has been determined, the limit verification unit determines that the limits of the stability envelope have been reached when the maximum distance exceeds the longest distance at which the trajectory sensor can operate,
wherein the control adapter is configured to adapt said control parameters of the lateral controller when said limits have been reached, based on of the current state of the vehicle.
2 . The system as claimed in claim 1 , wherein the current state of the vehicle is defined by at least one state parameter among a steering angle of the vehicle, a steering angular velocity of the vehicle, a speed of the vehicle, a target curvature of the vehicle at a current instant considered.
3 . The system as claimed in claim 1 , wherein the control conditions define acceptability conditions of a set of predefined vehicle control objectives.
4 . The system as claimed in claim 1 , wherein the lateral control device further comprises a minimal performance verification unit configured to verify conditions relating to a set of auxiliary parameters that relate to a quality of a response of the vehicle to the control applied by the lateral control device, said control parameters comprising at least:
a reliability parameter of the response of the vehicle to the control, and
a feasibility parameter of the response of the vehicle with respect to dynamics of the vehicle as a function of the maximum distance determined by the maximum distance determination unit.
5 . The system as claimed in claim 4 , wherein a level of the quality of the control adapter is determined by the minimal performance verification unit, the minimal performance verification unit being configured to generate an alert signal when the quality level of the control adapter is greater than a predefined threshold.
6 . The system as claimed in claim 1 , wherein the lateral control device further comprises a vehicle actuator manager configured to manage at least one actuator of the vehicle as a function of the maximum distance calculated by the maximum distance determination unit and of an output of the lateral controller.
7 . The system as claimed in claim 1 , wherein the lateral control device further comprises a display manager configured to generate a display of a control mode of the vehicle as a function of an output of the maximum distance determination unit and of a quality level of the control adapter, the control mode comprising a mode among a non-autonomous mode, in which the control system is not activated, and an autonomous mode, in which the control system is activated.
8 . The system as claimed in claim 1 , wherein the control adapter is configured to adapt the control parameters based on of a minimization of the difference between a target yaw rate of the vehicle and a current yaw rate of the vehicle.
9 . The system as claimed in claim 8 , wherein the target yaw rate of the vehicle is calculated based on of a target curvature of the vehicle and the current position of the vehicle.
10 . The system as claimed in claim 8 , wherein the control adapter is configured to minimize a yaw rate error by multiplying it by a controller gain.
11 . A vehicle control method implemented in a vehicle comprising a perception system that uses at least one vehicle trajectory sensor to determine a road layout, the road layout representing a trajectory to be followed by the vehicle, and a lateral controller that performs a lateral control of the vehicle defined by a set of control parameters, based on of a minimization of a difference in a control value between a reference trajectory curve of the vehicle and a current trajectory curve being described by the vehicle, which corresponds to a current state of the vehicle including an e-horizon provided by the trajectory sensor, the e-horizon being a longest distance at which the trajectory sensor can operate, the method comprising, for the current state of the vehicle, the following steps:
determining road layout information items corresponding to the current state of the vehicle based on of information items provided by said perception system, the road layout being represented by a polynomial function;
projecting the road layout information items that have been determined to a given distance ahead of the vehicle;
determining the maximum distance at which said polynomial function satisfies one or more control conditions based on of the projected road layout information items;
determining a stability envelope of the vehicle, which is defined by limits corresponding to application conditions of a control adapter of the vehicle;
determining whether said limits of the stability envelope have been reached by the vehicle based on of the maximum distance that has been determined, and the limits of the stability envelope are determined to have been reached when the maximum distance exceeds the longest distance at which the trajectory sensor can operate; and
adapting said control parameters of the control adapter when said limits have been reached, based on of the current state of the vehicle.
12 . A non-transitory computer readable medium storing a computer program that, when executed by a computer, causes the computer to execute the steps of the vehicle control method as claimed in claim 11 .