Systems and methods for transitioning control of an autonomous vehicle to a driver

A system comprising:

• at least one processor;
• and
• a memory having stored thereon executable instructions that, upon execution by the at least one processor, cause the system to perform functions comprising:
• operating a vehicle in an autonomous mode, wherein a steering wheel is substantially disengaged from manual control of a steering system of the vehicle;
• receiving an engage signal corresponding to at least a threshold change in torque applied to the steering wheel;
• determining a vehicle state upon receiving the engage signal, wherein the vehicle state includes an indication of a speed of the vehicle;
• based at least in part on the vehicle state, determining a transition period to transition the vehicle from the autonomous mode to a manual mode, wherein the determined transition period is a duration of time from when the system begins to decrease torque applied to the steering system by the autonomous control process to when the transition to a manual control of the steering system is complete;
• decreasing, over the transition period, torque applied to the steering system by an autonomous control process at a rate based on the speed of the vehicle;
• and
• by the end of the transition period, completing the transition from the autonomous mode to a manual mode by engaging the steering wheel to allow manual control of the steering system and ceasing use of the autonomous control process.

A non-transitory computer readable medium having stored thereon executable instructions that, upon execution by a computing device, cause the computing device to perform functions comprising:

• operating a vehicle in an autonomous mode, wherein a steering wheel is substantially disengaged from manual control of a steering system of the vehicle;
• receiving an engage signal corresponding to at least a threshold change in torque applied to the steering wheel;
• determining a vehicle state upon receiving the engage signal, wherein the vehicle state includes an indication of a speed of the vehicle;
• selecting a preferred transition strategy from a plurality of transition strategies, based on the vehicle state, to transition the vehicle from the autonomous mode to a manual mode, by following at least the following requirements of the plurality of transition strategies including:
• (a) determining a transition period based, at least in part, on the speed of the vehicle, wherein the determined transition period is a duration of time from when the computing system begins to decrease torque applied to the steering system by the autonomous control process to when the transition to a manual control of the steering system is complete;
• (b) decreasing, over the transition period, torque applied to the steering system by an autonomous control process at a rate based on the speed of the vehicle;
• and
• (c) by the end of the transition period, completing the transition from the autonomous mode to a manual mode by engaging the steering wheel to allow manual control of the steering system;
• executing the preferred transition strategy and ceasing use of the autonomous control process.