Vehicle Backlash Detection via Motor and Wheel Speed Comparison
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Solution Overview
Problem
In motor-driven vehicles, existing damping elements are insufficient to address backlash and torsion characteristics, leading to vibrations and noise during sudden changes in driving torque, which conflicts with securing vehicle responsiveness and reducing noise, vibration, and harshness (NVH).
Innovation Solution
A system and method that includes motor speed and wheel speed detection units, a speed difference determination unit, a torsion speed determination unit, and a backlash determination unit to calculate rotational and torsion speeds, and determine if backlash occurs by comparing these speeds with a reference torsion speed, using equations to filter and determine the presence of backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If damping elements are added to address backlash and torsion characteristics, then vibration and noise are reduced, but device complexity increases
Solution Approach 1:
The patent replaces physical damping elements with a computational control system that uses sensors and algorithms to detect and compensate for backlash and torsion effects. The controller calculates torsion speeds and compares them with actual speeds to determine backlash occurrence, eliminating the need for additional mechanical damping components while achieving the same vibration and noise reduction效果
Solution Approach 2:
The patent introduces a controller as an intermediary between the motor and driving wheels that mediates the transmission of torque by detecting backlash conditions and adjusting motor torque commands accordingly. This intermediary computational layer enables precise control of backlash without requiring physical damping elements in the mechanical transmission path
2Object-generated harmful factors
If gradient restriction and filter are applied to generate optimal motor torque command, then noise, vibration and harshness are reduced, but vehicle responsiveness deteriorates
Solution Approach 1:
The patent implements dynamic control by continuously monitoring real-time operating conditions (motor speed, wheel speed, motor torque command) and adjusting the motor torque command dynamically based on detected backlash conditions. This dynamic approach allows the system to maintain high responsiveness during normal operation while only applying torque adjustments when backlash is actually detected, unlike static gradient restriction that continuously limits responsiveness
Solution Approach 2:
The patent employs feedback control by using sensors to detect actual motor and wheel speeds, comparing these with commanded values to determine backlash occurrence, and then using this feedback information to adjust subsequent motor torque commands. This closed-loop feedback mechanism maintains vehicle responsiveness by only intervening when necessary, rather than continuously restricting torque changes
3Object-generated harmful factors
If restriction value is calibrated for each section to control backlash, then backlash is relieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent enables the system to automatically detect and determine backlash conditions using real-time sensor data and computational algorithms without requiring manual calibration or precise manufacturing tolerances. The controller self-adjusts by comparing detected speeds with commanded values and identifies backlash based on torsion speed thresholds, eliminating the need for section-specific calibration values and reducing manufacturing precision requirements
Data Source
AI summary
A system and method for determining backlash in a driving system of a vehicle are provided. The system includes a motor speed sensor that detects a motor speed and a wheel speed sensor that detects a wheel speed. A speed difference determination unit receives the detected motor and wheel speeds and determines a rotational speed difference of the driving system. A torsion speed determination unit receives the determined rotational speed difference and determines a reference torsion speed for backlash determination of the driving system. A backlash determination unit receives the determined rotational speed difference and the determined reference torsion speed, determines a backlash speed corresponding to a difference between the rotational speed difference and the reference torsion speed, and determines whether backlash in the driving system occurs using the determined backlash speed.