Independent Wheel Torque Control Using Momentum Error Separation
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Solution Overview
Problem
Existing motion control systems for independently driven left and right vehicle wheels struggle to accurately correct torque differences caused by motor variations, failing to distinguish between internal motor differences and external influences like road gradients, leading to reduced control accuracy and vehicle instability.
Innovation Solution
A motion control device that calculates wheel torque values based on differences between reference and actual vehicle states, extracts momentum errors caused by motor torque differences, and adjusts wheel torque commands to account for external influences such as road gradients, enhancing control accuracy by correcting torque differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque difference correction is applied based on steering torque information, then control accuracy of driving forces is improved, but false corrections occur due to external influences like road gradients
Solution Approach 1:
The patent segments the momentum error into two distinct components: one caused by motor torque differences and another caused by external influences like road gradients. By separating these error sources, the system can apply correction only for motor torque differences while ignoring corrections for external factors, thus resolving the contradiction between control accuracy and vehicle stability.
Solution Approach 2:
The patent introduces momentum information as an intermediary parameter to mediate between steering torque information and torque correction. By using momentum error as an intermediate step, the system can filter out false corrections caused by external influences while maintaining accurate correction for actual motor torque differences.
2Stability of the object's composition
If torque difference correction is applied, then driving force balance is improved, but excessive correction occurs when external causes are not distinguished
Solution Approach 1:
The patent segments the momentum error into components from motor torque differences and external influences. This segmentation enables selective correction - applying torque correction only for motor differences while excluding corrections for external factors, thus improving driving force balance without excessive correction.
Solution Approach 2:
The patent uses momentum information as feedback to determine when torque correction is appropriate. By monitoring momentum error and its rate of change, the system provides feedback to distinguish between genuine motor torque differences requiring correction and external influences that should not trigger correction, balancing driving forces without over-correction.
Data Source
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AI summary
A motion control device independently drives left and right wheels by calculating a wheel torque value from a difference between a reference vehicle state quantity calculated from driver operation information or an operation instruction of a higher driving device and an actual vehicle state quantity calculated from information regarding a motion and a posture of the vehicle, and controlling a plurality of motors based on the wheel torque value. Furthermore, the motion control device calculates a momentum error from a difference between a reference momentum calculated based on a wheel rotation speed and a tire steering angle and an actual momentum calculated based on the information regarding the motion and the posture of the vehicle, extracts a momentum error caused by a torque difference of the motor from the calculated momentum error, calculates a wheel torque correction amount based on the extracted momentum error caused by the torque difference of the motor, adds the wheel torque correction amount to the wheel torque value, and outputs a wheel torque command to the plurality of motors.