Electric Motor Torque Control for Drive-Line Vibration Damping

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Solution Overview

Problem

Drive line vibrations induced by torque changes cause unpleasant driving experiences and potential mechanical damage, necessitating a solution to mitigate these vibrations.

Innovation Solution

Implementing an electric motor controller that measures motor speed, applies bandpass and highpass filters to isolate drive line oscillations, and generates a countering torque signal using proportional or proportional-integral control to dampen these oscillations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If torque changes are executed to respond to operator requests, then vehicle acceleration or braking performance is improved, but drive line vibrations are induced causing unpleasant driving experiences and potential mechanical damage

Engineering Contradiction:

Improvevehicle acceleration performanceVSAvoiddrive line vibrations

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The control system applies a counteracting torque from the electrical motor before or during the torque change to offset the vibrations induced by drive line oscillations. This preliminary anti-action prevents the harmful vibrations from occurring in the first place, allowing torque changes to be executed without causing unpleasant driving experiences or mechanical damage.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system continuously monitors drive line oscillations and uses this feedback to adjust the electrical motor's torque output in real-time. By measuring the oscillations and responding with appropriate counteracting torque, the system maintains vehicle performance while eliminating vibrations that would otherwise occur during acceleration or braking maneuvers.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If traditional vibration mitigation methods are used, then drive line vibrations are reduced, but additional hardware costs and system complexity are incurred

Engineering Contradiction:

Improvedrive line vibrationsVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The electrical motor serves a dual function: it provides the primary torque for vehicle propulsion while simultaneously acting as an active vibration mitigation device. By controlling the motor to generate counteracting torque, the system eliminates drive line vibrations without requiring separate mechanical vibration damping components, thereby reducing hardware costs and system complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The electrical motor is utilized for multiple purposes: it functions as both the primary propulsion device and as an active vibration control mechanism. This multi-functionality allows the system to mitigate drive line vibrations using existing hardware, avoiding the need for additional specialized vibration damping components and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Effectively reduces or eliminates drive line induced vibrations, enhancing driving comfort and preventing mechanical damage without additional hardware costs.

Implementation Method 1

A bandpass filter and a highpass filter are applied to the measured motor speed, with the pass band centered on the natural frequency of the drive line assembly. The filtering isolates the drive line induced oscillations of the motor speed.

Methodology Applied

Scientific EffectBandpass filtering: Filter (electronic)

Implementation Method 2

A controller then uses the detected drive line induced oscillations to generate a control output, subject to limiting. The controller can, for example, be implemented as a proportional or a proportional-integral controller. An oscillation mitigation torque signal corresponding to the control output is added to a torque command to remove the oscillation from the motor speed.

Methodology Applied

Scientific EffectVibration damping: Damping

Data Source

PatentUS12573974B2Mitigation of vehicle vibrations induced by drive-line oscillations

Publication Date: 2026.03.10 WHS ENERGY SOLUTIONS LLC

AI summary

An electric motor controller is equipped to mitigate drive line induced vehicle vibration. The motor speed is measured at the output of the motor, separately from any measurement of drive shaft or wheel speed. At least bandpass filtering is applied to the measured motor speed, at a pass band based on the natural frequency of the drive shaft. The filtering detects drive line induced oscillations of the motor speed. A controller uses the detected drive line induced oscillations to generate an oscillation control output, subject to limiting. An oscillation mitigation torque signal corresponding to the control output is added to a torque command for desired motor speed, to adjust for the oscillations. The adjusted torque command is used to control the motor, with a significant reduction in the oscillation of the motor's speed.