Variable Gain Control for Friction Clutch Driving Force Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional driving force transmission devices using friction clutches in vehicles face reduced responsiveness due to increased gaps between clutch plates, leading to longer startup times and potential self-excitation vibration and overshoot, which compromise transmission accuracy.
Innovation Solution
A driving force transmission device control apparatus that includes an electric motor, a pressing mechanism, and a friction clutch, with a target current calculating circuit and a correction circuit to adjust the voltage applied to the electric motor, reducing the difference between target and actual current, and dynamically adjusting feedback control gains based on actual current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If gaps between clutch plates are increased to reduce drag torque, then drag torque is reduced, but responsiveness is deteriorated due to longer time required for driving force transmission
Solution Approach 1:
The patent applies dynamics by making the feedback control gain variable rather than fixed. The gain is dynamically adjusted based on the absolute value of motor current, transitioning from a high gain during startup to a low gain during steady operation. This dynamic adjustment allows the system to optimize both responsiveness during engagement and energy efficiency during operation, resolving the contradiction between reduced drag torque and maintained responsiveness.
2Speed
If feedback control gain is set at high level to improve responsiveness, then responsiveness is improved, but self-excitation vibration and overshoot occur reducing transmission accuracy
Solution Approach 1:
The patent uses dynamics by implementing a variable feedback control gain that changes based on operating conditions. During startup when responsiveness is critical, a high gain is applied. Once the motor current exceeds a threshold indicating engagement is complete, the gain switches to a low value to eliminate self-excitation vibration and overshoot, thereby achieving both responsiveness and transmission accuracy at different stages of operation.
Solution Approach 2:
The patent applies periodic action through the time-based sequence of control gain adjustment. The control system operates in two distinct phases: an initial phase with high gain for rapid engagement, followed by a secondary phase with low gain for stable operation. This periodic switching of control parameters allows the system to achieve both responsiveness during engagement and precision during steady-state transmission.
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
The solution enables high-accuracy driving force transmission while maintaining responsiveness, by rapidly reducing gaps between clutch plates and preventing self-excitation vibration and overshoot, thus ensuring precise torque control.
Implementation Method 1
an electric motor; a pressing mechanism to convert a rotational force of the electric motor into an axial pressing force
Implementation Method 2
a friction clutch to be pressed by an axial cam thrust produced by the actuation of the cam mechanism. The driving force transmission device transmits a driving force between rotary members using the frictional force of the friction clutch
Data Source
AI summary
A control apparatus controls a driving force transmission device including: an electric motor; a pressing mechanism to convert the rotational force of the motor into an axial pressing force; friction clutches including friction members configured to come into frictional engagement with each other by the pressing force provided by the pressing mechanism. The driving force transmission device is configured to transmit a driving force between a pair of rotary members by the friction clutches. The apparatus includes: a target current calculating circuit to calculate a target current to be supplied to the motor; and a correction circuit to correct a voltage to be applied to the motor so as to reduce a difference between the target current and an actual current supplied to the motor. The correction circuit increases or reduces, in accordance with the actual current, the amount of correction of the voltage to be applied to the motor.