Controller, system and method for vehicle control
A controller for a vehicle includes a processor configured to repeatedly perform operations, at each control iteration among a plurality of control iterations along a path of the vehicle from a start location to a target location. The operations include, based on a current state of the vehicle, generating a travel plan for a remainder of the path from a current position of the vehicle to the target location, by solving an optimization problem. The operations further include controlling a motoring and braking system of the vehicle to execute the generated travel plan until a next control iteration among the plurality of control iterations.
1. A controller for a vehicle, the controller comprising:
a processor configured to repeatedly perform, at each control iteration among a plurality of control iterations along a path of the vehicle from a start location to a target location, operations including
based on a current state of the vehicle, generating a travel plan for a remainder of the path from a current position of the vehicle to the target location, by solving an optimization problem, and
controlling a motoring and braking system of the vehicle to execute the generated travel plan until a next control iteration among the plurality of control iterations, wherein the processor is further configured to solve the optimization problem based on the current state of the vehicle, at least one control objective, and at least one constraint,
the at least one constraint comprises a first brake constraint and a second brake constraint, the second brake constraint corresponding to a harder brake operation than the first brake constraint,
the processor is further configured to
solve the optimization problem constrained by the first brake constraint,
in response to a determination that the optimization problem constrained by the first brake constraint is feasible, control the motoring and braking system of the vehicle based on a solution of the optimization problem, and
in response to a determination that the optimization problem constrained by the first brake constraint is infeasible, solve the optimization problem constrained by the second brake constraint corresponding to the harder brake operation.
2. The controller of claim 1 , wherein
the optimization problem includes a convex second order cone problem.
3. The controller of claim 1 , wherein
the processor is configured to change, in real-time while the vehicle is travelling on the path, one or more of
the at least one control objective, and
the at least one constraint.
4. The controller of claim 1 , wherein
the optimization problem includes a convex second order cone problem, and the processor is configured to determine whether the convex second order cone problem is feasible or not in a single control iteration.
5. The controller of claim 1 , further comprising:
a communication circuit configured to perform communication with a further controller of a trailing vehicle that follows the vehicle with the controller on the path from the start location to the target location,
wherein the processor is further configured to repeatedly perform, at each control iteration among the plurality of control iterations along the path from the start location to the target location,
causing the communication circuit to transmit a driving profile corresponding to the travel plan generated in said control iteration to the further controller of the trailing vehicle to be used by the further controller as a constraint in generating a further travel plan for the trailing vehicle.
6. The controller of claim 1 , further comprising:
a communication circuit configured to perform communication with a further controller of a leading vehicle that the vehicle with the controller follows on the path from the start location to the target location,
wherein the processor is further configured to repeatedly perform, at each control iteration among the plurality of control iterations along the path from the start location to the target location,
causing the communication circuit to receive, from the further controller, a further travel plan of the leading vehicle, and
using the received further travel plan of the leading vehicle as a constraint in said generating the travel plan for the vehicle with the controller.
7. The controller of claim 1 , wherein
the processor is further configured to repeatedly perform, at each control iteration among the plurality of control iterations along the path from the start location to the target location,
estimating a parameter of the vehicle, and
using the estimated parameter in said generating the travel plan for the vehicle.
8. The controller of claim 1 , wherein
the processor is further configured to perform said generating the travel plan for the remainder of the path from the current position of the vehicle to the target location by
determining, between the current position and the target location, a predicted position of the vehicle corresponding to a delay of the motoring and braking system,
solving the optimization problem to determine a first part of the travel plan between the predicted position and the target location, and
determining, based on the first part of the travel plan, a second part of the travel plan between the current position and the predicted position.
9. A system for controlling a plurality of vehicles along a common path, the system comprising:
a first controller associated with a leading vehicle among the plurality of vehicles, the first controller configured to
generate a first driving profile, and
control movement of the leading vehicle along the path based on the generated first driving profile; and
a second controller associated with a trailing vehicle among the plurality of vehicles, the second controller configured to
receive the first driving profile generated by the first controller,
generate a second driving profile based on the received first driving profile, and
control movement of the trailing vehicle along the path and following the leading vehicle based on the generated second driving profile,
wherein each of the first and second controllers is configured to repeatedly perform, at each control iteration among a plurality of control iterations along the path from a start location to a target location, operations including
based on a current state of the corresponding leading or trailing vehicle, generating a travel plan for the corresponding leading or trailing vehicle on a remainder of the path from a current position of the corresponding leading or trailing vehicle to the target location, and
controlling a motoring and braking system of the corresponding leading or trailing vehicle to execute the generated travel plan until a next control iteration among the plurality of control iterations, and
wherein said generating the travel plan for the corresponding leading or trailing vehicle for the remainder of the path from the current position of the leading or trailing vehicle to the target location includes:
determining, between the current position of the leading or trailing vehicle and the target location, a predicted position of the leading or trailing vehicle corresponding to a delay of the motoring and braking system,
solving an optimization problem, by the first or second controller, to determine a first part of the travel plan between the predicted position and the target location, and
determining, based on the first part of the travel plan, a second part of the travel plan between the current position and the predicted position.
10. The system of claim 9 , wherein
the first and second controllers further comprise first and second communication circuits, respectively, configured to perform one-way communication with each other to transmit the first driving profile from the first controller to the second controller.
11. The system of claim 9 , wherein
the second controller is further configured to perform said generating the travel plan for the trailing vehicle based on the first driving profile received from the first controller, the first and second driving profiles corresponding to the travel plans generated by the first and second controllers, respectively, for the leading vehicle and the trailing vehicle, respectively.
12. The system of claim 9 , wherein
the second controller is configured to generate the second driving profile by solving the optimization problem using the received first driving profile as a constraint.
13. The system of claim 12 , wherein
the first controller is configured to generate the first driving profile by solving the optimization problem, and
the optimization problem solved by the second controller and the optimization problem solved by the first controller have at least one common control objective.
14. The system of claim 12 , wherein
the first controller is configured to generate the first driving profile by solving the optimization problem, and
the optimization problem solved by the second controller and the optimization problem solved by the first controller have different control objectives.
15. The system of claim 9 , further comprising:
a third controller associated with a further trailing vehicle among the plurality of vehicles, the further trailing vehicle following the trailing vehicle,
wherein the third controller is configured to
receive the second driving profile generated by the second controller,
generate a third driving profile based on the received second driving profile, and
control movement of the further trailing vehicle along the path and following the trailing vehicle based on the generated third driving profile.
16. The system of claim 9 , wherein
solving the optimization problem with respect to the leading or trailing vehicle is performed based on the current state of the leading or trailing vehicle, at least one control objective, and at least one constraint,
the at least one constraint comprises a first brake constraint and a second brake constraint of the leading or trailing vehicle, the second brake constraint corresponding to a harder brake operation than the first brake constraint,
the system further configured to:
solve the optimization problem constrained by the first brake constraint,
in response to a determination that the optimization problem constrained by the first brake constraint is feasible, control the motoring and braking system of the leading or trailing vehicle based on a solution of the optimization problem, and
in response to a determination that the optimization problem constrained by the first brake constraint is infeasible, solve the optimization problem constrained by the second brake constraint corresponding to the harder brake operation.
17. A method of controlling a vehicle, the method comprising:
repeatedly performing, at each control iteration among a plurality of control iterations along a path of the vehicle from a start location to a target location, operations including
based on a current state of the vehicle, generating a travel plan for a remainder of the path from a current position of the vehicle to the target location, by performing convex optimization, and
controlling a motoring and braking system of the vehicle to execute the generated travel plan to move the vehicle along the path,
wherein the convex optimization comprises a second order cone problem and
wherein the method performs said generating the travel plan for the remainder of the path from the current position of the vehicle to the target location by
determining, between the current position and the target location, a predicted position of the vehicle corresponding to a delay of the motoring and braking system,
solving the optimization problem to determine a first part of the travel plan between the predicted position and the target location, and
determining, based on the first part of the travel plan, a second part of the travel plan between the current position and the predicted position.
18. The method of claim 17 , wherein
the plurality of control iterations corresponds to a plurality of discretization nodes on the path between the start location and the target location, and
said repeatedly performing comprises, at each discretization node among the plurality of discretization nodes,
performing the convex optimization, based on the current state of the vehicle, to generate a control vector including control elements corresponding to discretization nodes remaining on the path from the current position of the vehicle to the target location, and
controlling the motoring and braking system of the vehicle to execute a first control element among the control elements of the generated control vector to move the vehicle to a next discretization node among the discretization nodes remaining on the path.
19. The method of claim 18 , wherein
said defining comprises distributing the plurality of discretization nodes
at a predetermined distance from each other, or
at a predetermined time interval from each other.
20. The method of claim 17 , wherein
solving the optimization problem is performed based on the current state of the vehicle, at least one control objective, and at least one constraint,
the at least one constraint comprises a first brake constraint and a second brake constraint, the second brake constraint corresponding to a harder brake operation than the first brake constraint,
the method further comprises:
solving the optimization problem constrained by the first brake constraint,
in response to a determination that the optimization problem constrained by the first brake constraint is feasible, controlling the motoring and braking system of the vehicle based on a solution of the optimization problem, and
in response to a determination that the optimization problem constrained by the first brake constraint is infeasible, solving the optimization problem constrained by the second brake constraint corresponding to the harder brake operation.