[Inspire]액추에이터의 프로필 에디터에서 오실레이팅 함수에 관한 문의

Eddie_Han

안녕하십니까 대학교 자작자동차 동아리에서 서스펜션을 설계하고 있는 대학생입니다.

인스파이어의 모션에 있는 액추에이터로 진동하는 사인파를 만들어서 지면의 범프 상황을 구현하려고 하고 있는 상황입니다.

액추에이터의 프로필 에디터에서 function은 오실레이팅을 선택하기만 하고 아직 자세한 값들은 바꾸지 않았는데, 그래프에서 진폭이 점점 커지면서 진동하는 것을 확인할 수 있었습니다. 저는 일정한 진폭을 가지고 계속 진동하도록 하고 싶은데, 무엇 때문에 진폭이 계속 커지면서 진동하고 있는지 모르겠습니다.

https://2024.help.altair.com/2024.1/inspire/en_us/topics/inspire/motion/profile_functions_c-1.htm 해당 링크에서는 아래 사진과 같이 제가 원하는 일정한 진폭의 정현파를 만들어내고 있고 저도 이러한 파형을 생성하고 싶습니다.

감사합니다.

SouravDas0306

Hello Eddie,

In Inspire’s actuator profile editor, when you select the “oscillating” function and notice the amplitude increasing over time, it’s usually because the default settings include an amplitude growth parametermeaning the amplitude grows exponentially or linearly instead of staying constant. To create a sine wave with a constant amplitude, you need to adjust the amplitude growth or damping parameters in the actuator profile editor. Look for options like “amplitude growth rate,” “damping,” or “envelope,” and set the growth rate to zero or disable any amplitude increase feature. This way, the sine wave will maintain a steady amplitude throughout the simulation, just like the constant oscillation shown in the reference image. If these settings aren’t obvious, you can manually input a sine wave function in the profile editor by defining the displacement as a function of time, such as Asin(ωt), where A is a constant amplitude and ω is the angular frequency, to precisely control the vibration behavior.

How to Achieve a Constant Amplitude Sine Wave (Recommended Approaches):

The key is often to explicitly define the sine wave using a mathematical expression rather than relying solely on a generic "oscillating" function, or to ensure all parameters for the oscillating function are set to achieve a constant amplitude.

Here are a few strategies you can try within Inspire:

1. Using a "Formula" or "Expression" Function (Most Recommended):Most advanced simulation software like Inspire has a "formula" or "expression" editor for defining actuator profiles. This gives you precise control.
   • The Formula: You'll want to use a standard sine wave formula:Asin(2πft+ϕ)Where:
     • A: Is your desired constant amplitude (e.g., the height of your bump).
     • f: Is your desired frequency (how often the bump occurs, in Hz).
     • t: Is time (this will likely be an internal variable in Inspire, often denoted as time or t).
     • ϕ: Is the phase shift (usually 0 for a simple start at zero displacement).
   • Steps in Inspire (General Guidance - specific menus might vary slightly):
     1. Go to your actuator's profile editor.
     2. Look for an option like "Function Type," "Profile Type," or "Input Method."
     3. Select "Formula," "Expression," "User Defined," or similar.
     4. Enter the formula. For example, if you want an amplitude of 50mm and a frequency of 2Hz, you would enter something like: 50 * sin(2 * PI * 2 * time) (Note: PI or pi is often used for π).
     5. Ensure your units are consistent (e.g., if A is in mm, your output will be in mm).
2. Carefully Configuring the "Oscillating" Function:If Inspire's "oscillating" function is meant to create a constant amplitude sine wave, you need to be very precise with its parameters.
   • Amplitude: There should be a specific input field for the "amplitude." Make sure this is set to your desired constant value.
   • Frequency/Period: Set the frequency (in Hz) or period (in seconds) as needed.
   • Damping/Decay: Crucially, look for any parameters related to "damping," "decay," "envelope," or "start/end amplitude." Ensure these are either zero, off, or set to maintain a constant amplitude. It's possible the default has a slight increasing envelope.
   • Initial/Final Values: Some oscillating functions allow you to define an initial and final amplitude. Make sure both are set to your desired constant amplitude.
3. Defining a "Table" or "Lookup" Function (Less Ideal but Possible):If all else fails, or for very specific non-standard waveforms, you could generate a sine wave in a spreadsheet (like Excel) and then import it into Inspire as a data table.
   • Steps:
     1. In Excel, create two columns: "Time" and "Displacement."
     2. Fill the "Time" column with small increments (e.g., 0, 0.01, 0.02, etc.).
     3. In the "Displacement" column, use the formula A*SIN(2*PI()*f*TimeCell) and drag it down.
     4. Save this as a .csv or text file.
     5. In Inspire's actuator profile, select a "Table," "Lookup," or "Data File" option and import your generated data.

Example of a Sine Wave (as you described):

Let's say you want:

• Amplitude (A): 50 mm (representing the height of your bump)
• Frequency (f): 2 Hz (meaning the car goes over 2 bumps per second, or the bump cycle repeats twice per second)

If you use the formula method, you would enter something like:50 * sin(2 * PI * 2 * time)

By explicitly defining your sine wave using a mathematical expression or by carefully configuring all parameters of the "oscillating" function, you should be able to achieve the constant amplitude vibration you're looking for to simulate your bump situation. Good luck with your car club project! :)

Regards

Sourav