Self-Driving Hybrid Deceleration Timing for Quiet Brake Blending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current deceleration control methods in vehicles with partially automated driving using non-thermal powertrains face issues such as discontinuities in braking and noise from hydraulic pumps due to rapid dynamics in the braking system, particularly during all-electric driving phases, as they fail to account for the time needed for energy recovery and hydraulic pump activation.
Innovation Solution
A deceleration control method that introduces a three-phase braking strategy: a purely recuperative phase with the non-thermal driving machine, a mixed phase combining energy recovery and hydraulic braking, and a purely hydraulic phase, allowing for smoother deceleration and reducing noise by determining the torque and deceleration setpoints based on constraints and the minimum authorized torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the control dynamics of the computer controlling automated driving is too fast compared to the second duration, then the deceleration control responds quickly to the driver's request, but the distribution in the braking system is not carried out correctly causing discontinuity in the overall deceleration and the hydraulic pumps cannot anticipate the activation causing noise
Solution Approach 1:
The patent applies preliminary action by determining the deceleration setpoint from a first chosen instant preceding the second instant when minimum authorized torque is actually reached. This anticipatory timing allows the braking system to prepare and distribute the deceleration instruction before the regenerative braking torque is fully available, ensuring smooth transition and preventing discontinuities in the overall deceleration profile.
2Speed
If the control dynamics of the computer controlling automated driving is too fast compared to the second duration, then the deceleration control responds quickly to the driver's request, but the hydraulic pumps cannot anticipate the activation which induces noise
Solution Approach 1:
The patent applies preliminary action by determining the deceleration setpoint from a first chosen instant preceding the second instant when minimum authorized torque is actually reached. This anticipatory timing allows the braking system to prepare and distribute the deceleration instruction before the regenerative braking torque is fully available, ensuring smooth transition and preventing discontinuities in the overall deceleration profile.
3Speed
If the deceleration instruction is sent with very rapid dynamics, then the response to driver request is immediate, but it can induce noise when the hydraulic pumps are activated
Solution Approach 1:
The patent applies preliminary action by determining the deceleration setpoint from a first chosen instant preceding the second instant when minimum authorized torque is actually reached. This anticipatory timing allows the braking system to prepare and distribute the deceleration instruction before the regenerative braking torque is fully available, ensuring smooth transition and preventing discontinuities in the overall deceleration profile.
4Use of energy by moving object
If the braking system is activated after the minimum authorized torque is reached, then the energy recovery is maximized, but the transition causes discontinuity in the overall deceleration
Solution Approach 1:
The patent applies preliminary action by determining the deceleration setpoint from a first chosen instant preceding the second instant when minimum authorized torque is actually reached. This anticipatory timing allows the braking system to prepare and distribute the deceleration instruction before the regenerative braking torque is fully available, ensuring smooth transition and preventing discontinuities in the overall deceleration profile.
Solution Approach 2:
The patent applies dynamics by implementing a three-phase braking strategy that dynamically transitions between regenerative braking and hydraulic braking. The system adaptively adjusts the contribution of each braking source based on the available regenerative torque and system state, ensuring continuous and smooth deceleration throughout the braking maneuver.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach avoids discontinuities in braking and reduces noise from hydraulic pumps by effectively managing the transition between energy recovery and hydraulic braking, ensuring a smoother and quieter deceleration process.
Implementation Method 1
a non-thermal prime mover providing torque for at least one train of the vehicle from energy stored in an energy storage means or inducing deceleration of the vehicle by recovering energy from the train to supply energy to the energy storage means
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A method for controlling the deceleration of a partially self-driving vehicle comprising a non-combustion power unit supplying torque to an axle assembly or decelerating same by recovering energy from the axle assembly according to a torque setpoint, and a braking system decelerating same according to a deceleration setpoint. This method comprises a step (10-50) in which, in the event of a need to decelerate during a self-driving phase, the torque setpoint is determined as a function of a minimum authorised torque and of constraints until this torque is reached, and the deceleration setpoint is determined as a function of the constraints and from a chosen first instant preceding a second instant at which the minimum authorised torque is reached, so that, between the first and second instants, the deceleration is the result of the recovery of energy and of the braking system.