BACKGROUND

Some vehicles may operate in various modes which provide different levels of control to a driver. For instance, typical vehicles may operate in manual driving modes, where a driver controls acceleration, deceleration, and steering of the vehicle as well as semi-autonomous mode, such as cruise control, where computing devices of the vehicle control acceleration and deceleration while a driver controls steering, etc. In some instances, these vehicles may also operate in autonomous driving modes where the computing devices of the vehicle controls all of braking, all of the acceleration, deceleration and steering of the vehicle without continuous input from a driver or passenger. In the autonomous mode, the passenger may provide some initial input, such as a destination location, and the vehicle maneuvers itself to that destination.

Typically when operating in an autonomous mode, where the human driver has no input on the control of the vehicle's acceleration, deceleration or steering, a switch to manual mode can be made using input at a steering wheel, acceleration or deceleration pedal, or other some other user input. When using one of these inputs to change modes, there is an inherent delay between the time when the driver uses the input to when the vehicle's control computing devices (which control the vehicle in the autonomous driving mode) completely release control of the acceleration, deceleration and steering. In order to allow a safe transition where the driver is guaranteed control of the vehicle this “transition” may effectively cause the vehicle's control computing devices to immediately cease sending signals to the acceleration, deceleration, and steering systems of the vehicle.

BRIEF SUMMARY

One aspect of the disclosure provides a method of controlling a transition between a manual driving mode and an autonomous driving mode of a vehicle. The method includes controlling, by one or more processors of one or more control computing devices, the vehicle in the autonomous driving mode; while controlling the vehicle in the autonomous driving mode and decelerating at a given rate, receiving, by the one or more processors at a user input of the vehicle, input requesting a transition from the autonomous driving mode to the manual driving mode; in response to the input, transitioning the vehicle to the manual driving mode; and after transitioning the vehicle to the manual driving mode, sending, by the one or more processors, deceleration signals to a deceleration actuator thereby causing the vehicle to continue to decelerate at the given rate.

In one example, the method also includes, after receiving the input, determining that the one or more control computing devices are currently causing the vehicle to deceleration, and wherein sending the deceleration signals is based on the determination that the control computing devices are currently causing the vehicle to deceleration. In this example, the method also includes, after determining that the one or more control computing devices are currently causing the vehicle to deceleration, comparing an amount of deceleration currently requested by the control computing devices to a threshold deceleration, and wherein sending the deceleration signals is further based on the comparison. In another example, the method also includes, identifying a distance that user input has moved to cause the input, and wherein the deceleration signals are sent further based on the distance. In another example, the method also includes, identifying a force on the user input to cause the input, and wherein the deceleration signals are sent further based on a magnitude of the force. In another example, the deceleration signals are sent according to a current plan of operation by the one or more control computing devices when that the input is received. In another example, the method also includes continuing to send the deceleration signals to the deceleration actuator until a deceleration signal initiated by input at a deceleration pedal of the vehicle reaches the deceleration actuator. In another example, the method also includes continuing to send the deceleration signals to the deceleration actuator until an acceleration signal initiated by user input at a deceleration pedal of the vehicle reaches an acceleration actuator of the vehicle that causes the vehicle to accelerate. In another example, the user input is a steering wheel of the vehicle. In another example, the user input is a brake pedal of the vehicle. In another example, while controlling the vehicle in the autonomous driving mode and decelerating at the given rate, the vehicle is also changing orientation at a second given rate, and wherein the method further comprises, after transitioning the vehicle to the manual driving mode, sending, by the one or more processors, steering orientation signals to a steering actuator thereby causing the vehicle to continue to change orientation at the second given rate.

Another aspect of the disclosure provides a system for controlling a transition between a manual driving mode and an autonomous driving mode of a vehicle. The system comprising one or more processors configured to control the vehicle in the autonomous driving mode; while controlling the vehicle in the autonomous driving mode and decelerating at a given rate, receive, at a user input of the vehicle, input requesting a transition from the autonomous driving mode to the manual driving mode; in response to the input, transition the vehicle to the manual driving mode; and after transitioning the vehicle to the manual driving mode, send deceleration signals to a deceleration actuator thereby causing the vehicle to continue to decelerate at the given rate.

In one example, the one or more processors are further configured to, after receiving the input, determine that the one or more control computing devices are currently causing the vehicle to deceleration, and wherein sending the deceleration signals is based on the determination that the one or more control computing devices are currently causing the vehicle to deceleration. In this example, the one or more processors are further configured to, after determining that the one or more control computing devices are currently causing the vehicle to deceleration, compare an amount of deceleration currently requested by the one or more control computing devices to a threshold deceleration, and wherein sending the deceleration signals is further based on the comparison. In another example, the one or more processors are further configured to, identify a distance that user input has moved to cause the input, and wherein the deceleration signals are sent further based on the distance. In another example, the one or more processors are further configured to identify an amount of force on the user input to cause the input, and wherein the deceleration signals are sent further based on the amount of force. In another example, the one or more processors are further configured to continue to send the deceleration signals to the deceleration actuator until a deceleration signal initiated by input at a deceleration pedal of the vehicle reaches the deceleration actuator. In another example, the one or more processors are further configured to continue to send the deceleration signals to the deceleration actuator until an acceleration signal initiated by user input at a deceleration pedal of the vehicle reaches an acceleration actuator of the vehicle that causes the vehicle to accelerate. In another example, while controlling the vehicle in the autonomous driving mode and decelerating at the given rate, the vehicle is also changing orientation at a second given rate, and the one or more processors are further configured to, after transitioning the vehicle to the manual driving mode, send steering orientation signals to a steering actuator thereby causing the vehicle to continue to change orientation at the second given rate. In another example, the system also includes the vehicle.

