Drive Axle Regenerative Braking Control for Variable Vehicle Loads
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Solution Overview
Problem
Existing vehicle systems with regenerative brake systems struggle to adjust regenerative brake torque effectively when vehicle weight changes, leading to inconsistent deceleration rates and reduced drivability due to unknown or varying loads.
Innovation Solution
A method for controlling a drive axle system that adjusts regenerative brake torque based on propulsion torque utilization and vehicle speed, using a regeneration torque multiplier to account for different vehicle types and loads, without requiring weight sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regenerative brake torque is applied without adjusting for vehicle weight variations, then the system structure remains simple, but deceleration consistency deteriorates across different vehicle configurations
Solution Approach 1:
The system dynamically adjusts the regenerative brake torque by changing the torque multiplier parameter based on propulsion torque utilization amount. This allows the same control system to adapt to different vehicle weights and configurations without adding physical sensors, resolving the contradiction between deceleration consistency and system complexity
Solution Approach 2:
The system uses existing sensor data (propulsion torque utilization amount and vehicle speed) to automatically determine vehicle type and adjust regenerative brake torque. The system serves itself by leveraging available information rather than requiring additional weight sensors, maintaining simplicity while improving consistency
2Reliability
If vehicle weight sensors are added to directly measure weight for regenerative brake control, then deceleration consistency improves, but device complexity and cost increase
Solution Approach 1:
The system uses propulsion torque utilization amount as an intermediary parameter to indirectly represent vehicle weight. Instead of directly measuring weight with sensors, the system infers weight information from the relationship between commanded torque and actual torque delivery, eliminating the need for additional weight sensors
Solution Approach 2:
The existing torque sensing system serves multiple functions: it both controls propulsion and provides weight estimation for regenerative braking. This multi-functionality allows the system to achieve accurate deceleration control without adding dedicated weight sensors, reducing overall system complexity
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
Improves drivability by dynamically adjusting regenerative brake torque to match changing vehicle weights, ensuring consistent deceleration rates and reducing the need for additional weight sensing equipment.
Implementation Method 1
An electrical machine of the drive axle system provides propulsion torque to a vehicle wheel... Regenerative brake torque is provided with the electrical machine to the vehicle wheel
Data Source
AI summary
A drive axle system and a method of control. The method includes providing propulsion torque with an electrical machine to a vehicle wheel based on a torque command signal. A propulsion torque utilization amount is based on the torque command signal. A regeneration torque multiplier is based on the propulsion torque utilization amount and a signal indicative of speed of the vehicle. Regenerative brake torque is provided with the electrical machine to the vehicle wheel based on the regeneration torque multiplier.