Drive Motor Torque Control Using Drivetrain Torsion Modeling
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Solution Overview
Problem
Existing traction control systems in vehicles face challenges in accurately controlling drive torque due to the mechanical properties of the drive train, such as torsion and transmission backlash, leading to overly-sensitive torque reductions and loss of traction.
Innovation Solution
A dynamic model of the drive train is implemented in a motor controller to account for torsion and transmission backlash, allowing for direct control of drive torque based on the motor's actual speed and compensating for these mechanical effects to prevent sensitive torque reductions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a traditional traction control system is used without drive train modeling, then the control response time is longer due to signal transit delays, but the system is simpler to implement
Solution Approach 1:
A dynamic model of the drive train is introduced as an intermediary component between the motor controller and the wheel. This model compensates for the mechanical effects (torsion, backlash) of the drive train, enabling the controller to predict and correct for these effects before they manifest as wheel slip, thereby reducing effective control latency without requiring hardware modifications
Solution Approach 2:
The patent replaces direct mechanical feedback from wheel speed sensors with a computational model that simulates drive train behavior. By substituting physical measurement and reaction with mathematical modeling and prediction, the system achieves faster effective response times while maintaining control accuracy
2Speed
If drive torque is reduced quickly in response to detected wheel slippage, then traction control response is faster, but the mechanical deformation of the drive train causes overly-sensitive torque reductions and loss of traction
Solution Approach 1:
The dynamic model performs preliminary calculations to predict how drive train deformation will affect wheel speed before torque reduction is applied. By anticipating the mechanical effects, the controller can adjust torque reduction commands in advance, preventing over-correction and maintaining reliable traction control
Solution Approach 2:
The system implements improved feedback by continuously comparing actual wheel speed with predicted wheel speed from the dynamic model. This feedback loop allows the controller to distinguish between genuine wheel slip requiring correction and apparent slip caused by drive train deformation, thereby maintaining reliable traction control
3Device complexity
If the motor controller directly controls drive torque without compensating for drive train effects, then the control system is simpler, but the precision of wheel speed control deteriorates
Solution Approach 1:
The dynamic model incorporates multiple parameters including torsional stiffness, backlash characteristics, and inertial properties of drive train components. By adjusting these parameters in the computational model to match actual drive train properties, the system achieves precise wheel speed control prediction without requiring complex physical measurement systems
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 enables faster and more robust traction control with reduced latency, maintaining control quality by compensating for drive train deformations and preventing unnecessary torque reductions.
Implementation Method 1
a dynamic model of the drive train stored in a motor controller of the drive motor, wherein the model maps a relationship between a drive torque transmitted via the drive train and a deformation of the drive train
Implementation Method 2
Elements of the drive train are flexible to a small extent and can deform slightly due to the drive torque transmitted via the drive train
Data Source
AI summary
A method for operating a drive motor which is coupled to at least one wheel of a vehicle via a drive train. The drive motor is controlled using a dynamic model of the drive train. The model maps a relationship between a drive torque transmitted via the drive train and a deformation of the drive train.