Drivetrain Testing System Input Output Characteristic Estimation
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Solution Overview
Problem
In drive train bench systems, where multiple dynamometers are linked to a test piece, the existing methods for estimating input/output characteristics are inaccurate due to the influence of speed control devices, making it difficult to measure the response of target output signals to excitation inputs.
Innovation Solution
A testing system that includes multiple electric motors linked to shafts, state detection means for generating detection signals, and a speed control device to generate torque and rotation speed control inputs, allowing for excitation input generation and measurement of responses to estimate transfer functions from inputs to state detection signals, thereby eliminating the influence of speed control devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple dynamometers are linked to a test piece in a drive train bench system, then the system can evaluate performance of multi-shaft test pieces, but the input/output characteristic cannot be estimated with accuracy due to the influence of speed control devices
Solution Approach 1:
The patent divides the drive train system into separate excitation-controlled subsystems and measurement subsystems. By segmenting the control functions and measuring responses from each dynamometer independently, the system can isolate the mechanical characteristics from the speed control device influences, enabling accurate transfer function estimation despite multiple dynamometers being connected.
Solution Approach 2:
The patent introduces excitation control as an intermediary mechanism that temporarily overrides the normal speed control devices during measurement. This intermediary control mode allows direct injection of excitation signals and clean measurement of mechanical responses without the confounding effects of the speed control algorithms, thereby enabling accurate characteristic estimation.
2Stability of the object's composition
If speed control devices are used to control rotation speeds of dynamometers, then the system can maintain stable operation, but the influence of speed control devices prevents accurate estimation of input/output characteristics
Solution Approach 1:
The patent performs preliminary excitation control measurements before normal speed control operations. By conducting the characteristic estimation measurements first under excitation control conditions, the system captures the pure mechanical characteristics before the speed control devices are engaged, thereby eliminating their influence on the measurement results.
Solution Approach 2:
The patent employs periodic excitation signals superimposed on the control inputs during measurement phases. This periodic action allows the system to probe the mechanical characteristics at specific intervals while maintaining overall system stability, separating the measurement function from the continuous speed control function.
Data Source
AI summary
The input/output characteristic estimation method for testing system comprises; first excitation measurement steps (S3-S5) in which an input obtained by superimposing an excitation input d2 onto a second torque control input ib2 is input to a second dynamometer, and the frequency response i2d2 with respect to the excitation input d2 is measured; second excitation measurement steps (S7-S9) in which input obtained by superimposing excitation input d3 on third torque control input ib3 is input to a third dynamometer, and frequency response i2d3 with respect to the excitation input d3 and the like are measured; and mechanical characteristic estimation steps (S11 and S12) in which the response measured in the first and second excitation measurement steps are used to estimate the transfer function Gt2_i2 and the like from the second or third torque current command signals (i2, i3) to the first or second axial torque detection signals (t2 or t3).