Shaft Torque Control via Adaptive Gain and Variation Transfer Function
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Solution Overview
Problem
Existing shaft torque control devices in engine bench systems experience low control responsiveness due to varying spring rigidity at the connection shaft, particularly when spring rigidity is low, leading to instability in torque control.
Innovation Solution
A shaft torque control device is designed using a feedback control system with a nominal plant based on a two-inertia system, incorporating a controller that satisfies specific design conditions to manage varying spring rigidity, including the use of weighting functions and variation transfer functions to enhance responsiveness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gain parameter is set with the mechanical resonance frequency when spring rigidity is low as the reference, then stable control is achieved, but control responsiveness becomes low
Solution Approach 1:
The patent applies dynamics by making the gain parameter adaptive rather than fixed. The controller dynamically adjusts the gain parameter based on the actual spring rigidity of the connection shaft, switching between different gain values corresponding to different rigidity states (low, nominal, high). This allows the system to maintain stability across varying conditions while achieving high responsiveness when needed, resolving the contradiction between stable control and fast response.
2Adaptability or versatility
If the spring rigidity of the connection shaft varies, then the system must adapt to different rigidity conditions, but this variation causes control performance degradation
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual spring rigidity of the connection shaft and using this information to adjust the gain parameter. The controller receives feedback about the rigidity state and automatically selects the appropriate gain value from a set of pre-determined gains, ensuring optimal control performance adapts to varying spring rigidity conditions without manual intervention.
Data Source
AI summary
A shaft torque control device executes highly responsive shaft-torque control even when spring rigidity of a connection shaft connecting an engine and dynamometer varies, and has a feedback control system including a nominal plant imitating input-output characteristics of a test system, generalized plant having nominal plant; controller providing an input with use of outputs and variation term causing variation in the nominal plant on the basis of a variation transfer function. In the controller, setting is made to satisfy a design condition. Nominal plant is structured with a two-inertia system configured by connecting two inertia bodies via a shaft having spring rigidity equal to a predetermined nominal value set to be a lower limit value in an assumed variation range of spring rigidity of the connection shaft. The variation transfer function is a positive real function. Spring rigidity in the nominal plant Na increases from the nominal value.