Electric Drive Axle Torque Redistribution for Multi-Shaft Anti-Slip
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for anti-slip control in multi-shaft vehicles with electric drive axles lack a clear mechanism for adjusting torque distribution between drive shafts, especially when both front and rear drive shafts slip, which hampers the vehicle's ability to maintain traction on uneven terrain.
Innovation Solution
A method and device that periodically determine real-time demand torque and vehicle speed, and adjust torque distribution by subtracting specific torques from slipping drive shafts to maintain optimal slip rates, transferring excess torque to non-slipping shafts, ensuring rational torque distribution during starting, traveling, and slipping conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional mechanical differential control is used in multi-shaft vehicles, then the rotation speed coordination between wheels is achieved, but the system complexity increases due to mechanical connections between axles
Solution Approach 1:
The patent replaces the traditional mechanical differential system with an electric control system. Each drive shaft is equipped with an independent electric motor, and the control unit coordinates the rotation speeds of multiple drive shafts through electronic control signals rather than mechanical connections. This substitution eliminates the complex mechanical differential structure while achieving the same function of coordinating wheel rotation speeds.
2Device complexity
If independent electric drive axles are used without inter-axle differential structure, then the device complexity is reduced, but the ability to prevent slip between driving wheels on uneven terrain deteriorates
Solution Approach 1:
The patent incorporates feedback mechanisms where sensors detect the rotation speeds and slip conditions of each drive shaft independently. The control unit receives this feedback information and continuously adjusts the torque distribution and rotation speed of each electric motor to prevent slip. This closed-loop feedback control ensures reliable anti-slip performance even without mechanical differential connections.
Solution Approach 2:
The system dynamically adjusts the torque and rotation speed of each independent electric motor based on real-time road conditions and wheel slip detection. The control unit can independently modulate the output of each drive shaft, allowing adaptive response to uneven terrain and varying traction conditions, thereby maintaining anti-slip capability without fixed mechanical connections.
3Measurement precision
If torque is reduced from slipping drive shafts to maintain optimal slip rates, then the slip control precision is improved, but the power loss increases due to torque transfer to non-slipping shafts
Solution Approach 1:
The patent dynamically changes the torque distribution parameters between drive shafts based on real-time slip rate measurements. When slip is detected, the control unit adjusts the torque parameters of affected motors to maintain optimal slip rates within a predetermined range. This parameter adjustment enables precise slip control while minimizing energy loss by optimizing the torque transfer to non-slipping shafts only when necessary.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention provides a method and device for anti-slip control of torque between electric drive axle shafts of a multi-shaft vehicle, wherein a non-drive shaft or the drive shaft with the lowest rotation speed is selected as a reference shaft, a determination is made as to whether the vehicle is in a state of starting to move or a travelling state by judging whether the rotation speed of the reference shaft is greater than a predetermined rotation speed value; in a state of starting to move, a judgement is made as to whether a rotation speed difference between each drive shaft and the reference shaft is greater than a predetermined threshold, to determine whether each drive shaft is in a slipping state, and when the drive shaft is in a slipping state, a slip rate of each drive shaft is kept within a predetermined optimal slip rate range by torque transfer or torque reduction. In a travelling state, a judgement is made as to whether a slip rate of each drive shaft is greater than a predetermined optimal slip rate, to determine whether each drive shaft is in a slipping state, and when the drive shaft is in a slipping state, the slip rate of each drive shaft is kept within a predetermined optimal slip rate range by torque transfer or torque reduction. In this way, real-time, rational distribution of torque between electric drive axle shafts of the multi-shaft vehicle is achieved; moreover, when all of the multiple drive shafts of the vehicle are slipping, torque redistribution can be achieved, thereby making full use of the road surface adhesion coefficient of each shaft, and improving the vehicle's ability to cross terrain.