Platoon controller state machine

Abstract

Systems, methods, controllers and algorithms for controlling a vehicle to closely follow another vehicle safely using automatic or partially automatic control are described. The described control schemes are well suited for use in vehicle platooning and/or vehicle convoying applications, including truck platooning and convoying controllers. In one aspect, methods of initiating a platoon between a host vehicle and a platoon partner are described. In another aspect, a number of specific checks are described for determining whether a platoon controller is ready to initiate platoon control of the host vehicle. In another aspect, a platoon controller that includes a state machine that determines the state of the platoon controller is described. In another aspect, methods for generating braking alerts to a driver of a vehicle while the vehicle is being at least semi-automatically controlled by a platoon controller are described.

What is claimed is: 
     
         1 . A method for determining whether a platoon controller on a host vehicle is ready to initiate platoon control of the host vehicle, the method comprising:
 verifying that a platoon partner is currently in a ready to platoon state;   verifying that the platoon partner is within a designated range of the host vehicle;   verifying that communications between the host and the platoon partners are stable; and   verifying that a tracking unit on the host has a fix on the platoon partner.   
     
     
         2 . A method as recited in  claim 1  further comprising:
 verifying that a current deceleration of the platoon partner does not exceed an designated deceleration thresholds. 
 
     
     
         3 . A method as recited in  claim 1  further comprising:
 verifying that no cut-in vehicle has been detected between the host and the platoon partner. 
 
     
     
         4 . A method as recited in  claim 1  further comprising:
 verifying that the platoon partner is currently confirming that it is receiving stable communications from the host vehicle. 
 
     
     
         5 . A method as recited in  claim 1  further comprising:
 verifying that transitioning to platoon control at the current time would not cause generation of a braking request exceeding a designated braking request threshold. 
 
     
     
         6 . A method as recited in  claim 1  further comprising:
 verifying that at least two of platoon partner speed, host vehicle speed, and relative speed of the host vehicle relative to the platoon partner are within approved platooning limits. 
 
     
     
         7 . A platoon controller for controlling a host vehicle's participation in a platoon that includes the host vehicle and a partner vehicle, the platoon controller comprising a state machine that determines the state of the platoon controller, wherein available states of the state machine when the host vehicle is designated a trailing vehicle include:
 a rendezvous state;   a back system ready state;   a back ready to platoon state;   a back maintain platoon control state; and   a back dissolve platoon state.   
     
     
         8 . A platoon controller as recited in  claim 7  wherein the state machine can only transition to the back ready to platoon state when a corresponding platoon controller on the partner vehicle is in a front ready to platoon state that requires a driver of the partner vehicle to affirmatively indicate that the driver is ready to platoon. 
     
     
         9 . A platoon controller as recited in  claim 7  wherein the state machine can only transition to the back system ready state when a multiplicity of platooning prerequisite checks are met. 
     
     
         10 . A platoon controller as recited in  claim 9  wherein the platooning prerequisite checks include:
 verifying that a platoon partner is currently in a ready to platoon state; 
 verifying that the platoon partner is within a designated range of the host vehicle; 
 verifying that communications between the host and the platoon partners are stable; and 
 verifying that a tracking unit on the host has a fix on the platoon partner. 
 
     
     
         11 . A platoon controller as recited in  claim 7  wherein a driver of the trailing vehicle must affirmatively indicate that the driver is ready to platoon for the state machine to transition from the back ready to platoon state to the back maintain platoon control state. 
     
     
         12 . A platoon controller as recited in  claim 7  wherein available states of the state machine when the host vehicle is designated a leading vehicle include:
 a front rendezvous state; 
 a front system ready state; 
 a front ready to platoon state; and 
 a front maintain platoon state. 
 
     
     
         13 . A platoon controller as recited in  claim 7  wherein the platoon controller is further configured to perform a multiplicity of platooning requirement checks when the state machine is in the back maintain platoon control state, and wherein failure of any of the platooning requirement checks causes the state machine to transition to the back dissolve platoon state. 
     
     
         14 . A platoon controller as recited in  claim 13  wherein one of the platooning requirement checks monitors communications received from the platoon partner and will cause the state machine to transition from the back maintain platoon control state to the back dissolve state if reliable communications are not received from the platoon partner for a designated period of time. 
     
     
         15 . A platoon controller as recited in  claim 13  wherein one of the platooning requirement checks will cause the state machine to transition from the back maintain platoon control state to the back dissolve state when a vehicle of concern is identified in front of the platoon partner. 
     
     
         16 . A method for generating braking alerts to a driver of a vehicle while the vehicle is being at least semi-automatically controlled by a platoon controller as a trailing vehicle in a platoon, the method comprising:
 determining a desired braking level based at least in part on information received from a platoon partner that is in front of the trailing vehicle;   determining whether the desired braking level exceeds a maximum braking that can be commanded by the platoon controller; and   when it is determined that the desired braking level exceeds the maximum braking that can be commanded by the platoon controller and additional braking is deemed necessary, issuing an alert to the driver to manually apply brakes.   
     
     
         17 . A method as recite in  claim 16  wherein the alert includes a spoken audio notification that indicates urgency for braking. 
     
     
         18 . A method as recited in  claim 17  wherein the spoken alert is BRAKE NOW.