Control architectures for autonomous vehicles

Abstract

The subject matter described in this specification is generally directed control architectures for an autonomous vehicle. In one example, a reference trajectory, a set of lateral constraints, and a set of speed constraints are received using a control circuit. The control circuit determines a set of steering commands based at least in part on the reference trajectory and the set of lateral constraints and a set of speed commands based at least in part on the set of speed constraints. The vehicle is navigated, using the control circuit, according to the set of steering commands and the set of speed commands.

1 . A system comprising:
 one or more computer processors; and   one or more non-transitory storage media storing instructions which, when executed by the one or more computer processors, cause performance of operations comprising:   while a vehicle is operating in an autonomous mode:
 receiving, using a control circuit, a reference trajectory, a set of lateral constraints, and a set of speed constraints; 
 determining, using the control circuit, a curvature of the reference trajectory; 
 determining, using the control circuit, a set of steering commands and a set of speed commands based on the curvature of the reference trajectory, the set of lateral constraints, and the set of speed constraints; and 
 in response to determining that the determined set of steering commands and the set of speed commands satisfy a safety factor, navigating, using the control circuit, the vehicle according to the set of steering commands and the set of speed commands. 
   
     
     
         2 . The system of  claim 1 , wherein determining the set of steering commands includes:
 determining a lateral position of the vehicle over time based on a plurality of steering factors; and   determining the set of steering commands based at least in part on the determined lateral position of the vehicle over time.   
     
     
         3 . The system of  claim 2 , wherein the plurality of steering factors comprise one of more of a distance of the vehicle to an obstacle, a distance of the vehicle from the reference trajectory, or a threshold of lateral change. 
     
     
         4 . The system of  claim 3 , wherein the threshold of lateral change comprises a maximum allowed rate of turning of the vehicle. 
     
     
         5 . The system of  claim 1 , wherein determining the set of speed commands includes:
 determining a target speed of the vehicle over time that satisfies a comfort factor within the set of speed constraints; and   determining the set of speed commands based at least in part on the determined target speed of the vehicle over time.   
     
     
         6 . The system of  claim 5 , wherein the comfort factor comprises an acceleration or deceleration rate within predetermined acceleration or deceleration comfort boundaries. 
     
     
         7 . The system of  claim 1 , wherein the safety factor comprises an estimated likelihood of the set of steering commands and the set of speed commands resulting in a collision or dangerous/illegal maneuver being less than a threshold. 
     
     
         8 . The system of  claim 1 , wherein the reference trajectory comprises a path with respect to time received from a planning module of the vehicle. 
     
     
         9 . The system of  claim 1 , wherein the set of lateral constraints comprise maximum distances to left and right sides of the vehicle configured to enable the vehicle to safely veer from the reference trajectory at different points in time. 
     
     
         10 . The system of  claim 1 , wherein the set of speed constraints comprise one or more of roadway speed limits, physical acceleration or deceleration limits of the vehicle, or predetermined acceleration or deceleration comfort boundaries. 
     
     
         11 . A method comprising:
 receiving, using a control circuit, a reference trajectory, a set of lateral constraints, and a set of speed constraints;   determining, using the control circuit, a curvature of the reference trajectory;   determining, using the control circuit, a set of steering commands and a set of speed commands based on the curvature of the reference trajectory, the set of lateral constraints, and the set of speed constraints; and   in response to determining that the determined set of steering commands and the set of speed commands satisfy a safety factor, navigating, using the control circuit, the vehicle according to the set of steering commands and the set of speed commands.   
     
     
         12 . The method of  claim 11 , wherein determining the set of steering commands includes:
 determining a lateral position of the vehicle over time based on a plurality of steering factors; and   determining the set of steering commands based at least in part on the determined lateral position of the vehicle over time.   
     
     
         13 . The method of  claim 12 , wherein the plurality of steering factors comprise one of more of a distance of the vehicle to an obstacle, a distance of the vehicle from the reference trajectory, or a threshold of lateral change. 
     
     
         14 . The method of  claim 13 , wherein the threshold of lateral change comprises a maximum allowed rate of turning of the vehicle. 
     
     
         15 . The method of  claim 11 , wherein determining the set of speed commands includes:
 determining a target speed of the vehicle over time that satisfies a comfort factor within the set of speed constraints; and   determining the set of speed commands based at least in part on the determined target speed of the vehicle over time.   
     
     
         16 . The method of  claim 15 , wherein the comfort factor comprises an acceleration or deceleration rate within predetermined acceleration or deceleration comfort boundaries. 
     
     
         17 . The method of  claim 11 , wherein the safety factor comprises an estimated likelihood of the set of steering commands and the set of speed commands resulting in a collision or dangerous/illegal maneuver being less than a threshold. 
     
     
         18 . The method of  claim 11 , wherein the set of lateral constraints comprise maximum distances to left and right sides of the vehicle configured to enable the vehicle to safely veer from the reference trajectory at different points in time. 
     
     
         19 . The method of  claim 11 , wherein the set of speed constraints comprise one or more of roadway speed limits, physical acceleration or deceleration limits of the vehicle, or predetermined acceleration or deceleration comfort boundaries. 
     
     
         20 . A non-transitory computer-readable storage medium storing instructions which, when executed by one or more computer processors, cause performance of operations comprising:
 receiving, using a control circuit, a reference trajectory, a set of lateral constraints, and a set of speed constraints;   determining, using the control circuit, a curvature of the reference trajectory;   determining, using the control circuit, a set of steering commands and a set of speed commands based on the curvature of the reference trajectory, the set of lateral constraints, and the set of speed constraints; and   in response to determining that the determined set of steering commands and the set of speed commands satisfy a safety factor, navigating, using the control circuit, the vehicle according to the set of steering commands and the set of speed commands.