Autonomous parking with hybrid exploration of parking space

A control method for parking a vehicle within a parking space, wherein the method uses a processor coupled with stored instructions implementing the method, wherein the instructions, when executed by the processor carry out steps of the method, comprising:

• receiving an initial state of the vehicle in the parking space defining an initial position and an initial orientation of the vehicle, a target state of the vehicle in the parking space defining a target position and a target orientation of the vehicle, and a directed graph representing a traffic network within the parking space,
• wherein the directed graph includes waypoints connected by edges, each waypoint defines a position and an orientation for the vehicle to move along the directed graph, each edge defines a collision free path for the vehicle from one waypoint to a next waypoint in the directed graph, wherein the directed graph is predetermined for parking different vehicles at different target states in the parking space;
• identifying an initial waypoint on the directed graph closest to the initial state of the vehicle, based on the initial orientation of the vehicle;
• identifying a target waypoint on the directed graph closest to the target state of the vehicle, based on the target orientation of the vehicle;
• extracting a portion of the directed graph for selecting a coarse path defined by a shortest route of waypoints connecting the initial waypoint on the directed graph closest to the initial state of the vehicle with the target waypoint on the directed graph closest to the target state of the vehicle, wherein the coarse path does not connect the initial state of the vehicle with the target state of the vehicle;
• exploring the parking space using a guided heuristic search for constructing a tree having multiple nodes defining different states of the vehicle including an initial node defining the initial state of the vehicle and a target node defining the target state of the vehicle, wherein each pair of nodes in the tree is connected with an edge defined by kinematically feasible motion moving the vehicle between the states of the connected nodes without a collision, wherein the tree is constructed using the coarse path as heuristic guidance to reduce a deviation of a cost of a motion defined by a refined path connecting the initial node with the target node of the tree from a cost of the motion along the coarse path defining the route of waypoints;
• and
• controlling the vehicle based on the refined path.

A non-transitory computer-readable storage medium embodied thereon a program executable by a processor for performing a method, the method comprising:

• receiving an initial state of the vehicle in the parking space defining an initial position and an initial orientation of the vehicle, a target state of the vehicle in the parking space defining a target position and a target orientation of the vehicle, and a directed graph representing a traffic network within the parking space,
• wherein the directed graph includes waypoints connected by edges, each waypoint defines a position and an orientation for the vehicle to move along the directed graph, each edge defines a collision free path for the vehicle from one waypoint to a next waypoint in the directed graph, wherein the directed graph is predetermined for parking different vehicles at different target states in the parking space;
• identifying an initial waypoint on the directed graph closest to the initial state of the vehicle, based on the initial orientation of the vehicle;
• identifying a target waypoint on the directed graph closest to the target state of the vehicle, based on the target orientation of the vehicle;
• extracting a portion of the directed graph for selecting a coarse path defined by a shortest route of waypoints connecting the initial waypoint on the directed graph closest to the initial state of the vehicle with the target waypoint on the directed graph closest to the target state of the vehicle, wherein the coarse path does not connect the initial state of the vehicle with the target state of the vehicle;
• exploring the parking space using a guided heuristic search for constructing a tree having multiple nodes defining different states of the vehicle including an initial node defining the initial state of the vehicle and a target node defining the target state of the vehicle, wherein each pair of nodes in the tree is connected with an edge defined by kinematically feasible motion moving the vehicle between the states of the connected nodes without a collision, wherein the tree is constructed using the coarse path as heuristic guidance to reduce a deviation of a cost of a motion defined by a refined path connecting the initial node with the target node of the tree from a cost of the motion along the coarse path defining the route of waypoints;
• and
• controlling the vehicle based on the refined path.