Electric Vehicle Damping Control via Transmission Ratio Second-Order Differentiation
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Solution Overview
Problem
Existing damping control devices for electric vehicles with continuously variable transmissions fail to accurately detect changes in transmission ratio, leading to erroneous damping control and potential vibration issues during gear shifts.
Innovation Solution
A damping control device that includes a shift vibration suppression mechanism and a transmission ratio second-order differentiation calculating means, which calculates the second-order differential of the transmission ratio to determine if a change has occurred, allowing for accurate detection and correction of shifting-related vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a damping control device uses conventional transmission ratio detection methods, then the device complexity is reduced, but the measurement precision of transmission ratio changes deteriorates, leading to erroneous detection of shifting
Solution Approach 1:
The patent transforms the transmission ratio detection problem from direct measurement to indirect calculation by using second-order differentiation of motor rotational speed. This parameter transformation allows accurate detection of transmission ratio changes without adding complex sensing hardware, resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent replaces mechanical transmission ratio sensors with a computational approach using motor speed differentiation. This substitution eliminates the need for additional mechanical detection components while achieving precise transmission ratio change detection, thereby improving measurement precision without increasing device complexity
2Reliability
If the damping control operates during transmission ratio changes, then the vibration suppression effectiveness is improved, but the reliability of damping control deteriorates due to erroneous detection of shifting
Solution Approach 1:
By changing the detection parameter from direct transmission ratio measurement to second-order differentiation of motor speed, the system achieves reliable identification of genuine shifting events. This parameter transformation filters out false positives while capturing actual transmission ratio changes, improving reliability without compromising vibration suppression
Solution Approach 2:
The patent implements feedback control by continuously monitoring the second-order differential of motor speed and adjusting the damping torque accordingly. This feedback mechanism ensures that damping control is activated only when genuine shifting occurs, improving reliability while effectively suppressing vibration and thrusting shock
3Object-affected harmful factors
If the damping control subtracts compensation torque for shifting vibration, then the vibration suppression effectiveness is improved, but the loss of energy increases due to additional torque correction
Solution Approach 1:
The patent applies partial action by activating damping control only during detected shifting events rather than continuously. By using second-order differentiation to identify genuine shifting moments, the system applies torque correction only when necessary, suppressing vibration effectively while minimizing unnecessary energy consumption
Solution Approach 2:
The damping control operates periodically during shifting events rather than continuously. The second-order differentiation detects transient shifting moments, and the compensation torque is applied only during these brief periods, effectively suppressing shifting vibration while keeping energy loss minimal
Data Source
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AI summary
In order to provide a damping control device for an electric vehicle, a device enabling damping control corresponding to an accurate determination of the presence or absence of a change in transmission ratio in the present invention provides a damping control device for an electric vehicle, the device being characterized by being provided with a drive system, which has a continuously variable transmission (CVT) between a motor (MG) and left and right front wheels (FL and FR), a feedback control unit (32), which suppresses a vibration accompanying a disturbance in the rotational speed of the motor (MG), and an operation determination unit (301), which determines whether or not an absolute value of a second-order differential of the transmission ratio is equal to, or greater than, a predetermined value, wherein when the absolute value of the second-order differential of the transmission ratio is equal to, or greater than, the predetermined value, the feedback control unit (32) performs control of the output torque of the motor (MG) whereby a compensation torque component for suppressing a vibration accompanying a gear shift is subtracted from a compensation torque (Tm (F/B)).