Vehicle Subassembly NVH Testing Using Third Derivative Gaussian Torque
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Solution Overview
Problem
Vehicle manufacturers face challenges in accurately reproducing the noise and vibration responses of torsionally-compliant vehicle subassemblies in a lab setting to ensure compliance with noise, vibration, and harshness standards, as existing methods fail to accurately simulate in-use torque excitations.
Innovation Solution
A method and test apparatus that apply an input torque characterized as a third derivative Gaussian function to isolated vehicle subassemblies, using a controller to receive and analyze responses, and optionally apply a reaction torque to simulate in-vehicle conditions, allowing for accurate determination of noise and vibration compliance with predetermined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional testing methods are used to test vehicle subassemblies, then the test setup is simple, but the accuracy of reproducing in-use torque excitations is insufficient
Solution Approach 1:
The patent applies parameter changes by transforming the torque input from a simple constant or sinusoidal function to a third derivative Gaussian function. This specific mathematical function shape allows the test apparatus to accurately replicate the transient torque excitations that occur during actual vehicle operation, thereby significantly improving measurement precision while maintaining a relatively compact test setup.
Solution Approach 2:
The testing system transitions from static or simple dynamic testing to a more complex dynamic testing regime by using time-varying torque inputs characterized by the third derivative Gaussian function. This enables the system to capture the subassembly's response to realistic, changing torque conditions, improving accuracy without requiring excessive structural complexity.
2Measurement precision
If the vehicle subassembly is isolated to focus on its response, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent extracts the vehicle subassembly from the complete vehicle context and places it in an isolated test fixture. This extraction allows the subassembly to be tested independently with controlled torque inputs, eliminating the complexity of testing the entire vehicle while maintaining measurement precision through the specialized third derivative Gaussian torque generation capability.
Solution Approach 2:
The test apparatus acts as an intermediary between the simple test fixture and the complex real-world torque excitations. It generates the appropriate third derivative Gaussian torque function as an intermediate representation of in-use conditions, enabling accurate measurement without requiring the actual vehicle environment or complex test rigging.
3Measurement precision
If third derivative Gaussian function torque is applied to simulate in-use conditions, then the accuracy of noise and vibration response determination improves, but the control system complexity increases
Solution Approach 1:
The controller is pre-programmed with the third derivative Gaussian function that characterizes in-use torque excitations. This preliminary preparation of the torque input function allows the system to automatically generate realistic torque patterns without requiring complex real-time computation or adaptive control, thereby improving measurement precision while keeping the control system relatively simple.
Data Source
AI summary
A method of determining a noise or vibration response of a vehicle subassembly may include transmitting, via a controller, an input torque control signal to a first motor of a test apparatus. The first motor is mountable on a test fixture of the test apparatus and is configured to be coupled to the vehicle subassembly. The input torque control signal causes the first motor to provide an input torque characterized as a third derivative Gaussian function. The method further includes receiving a response of the vehicle subassembly to the input torque, and executing a control action with respect to the vehicle subassembly, via the controller, based on the response.