- Fast MEMS Simulation at the Device or System Level
- MEMS+ System Simulation in Simulink
- MEMS+ Simulink Design Flow
- MEMS+ Device Simulation in MATLAB
Fast MEMS Simulation at the Device or System Level
MATLAB and Simulink (from Mathworks) are powerful numerical tools for engineering innovation that are used across multiple engineering disciplines. Engineers use these tools to design domain-specific systems and to rapidly solve difficult engineering problems.
MEMS+ for MATLAB allows MEMS engineers to simulate their MEMS design in the familiar MATLAB and/or Simulink environment and deliver compatible MATLAB models to their counterparts in system architecture and IC design.
Designers can import a parameterized model created in the MEMS+ design platform directly into MATLAB or Simulink. MEMS+ requires no device physics programming (such as mechanical equations or capacitance extraction) or finite element analysis. A user simply creates a 3-D design in MEMS+ Innovator using the tool’s intuitive 3-D graphical interface. MATLAB or Simulink simulation results can be subsequently loaded back into the MEMS+ Results Visualization module for 3-D viewing. Using MEMS+ Results Visualization, all simulation results obtained with MATLAB or Simulink can be visualized as fully contoured three-dimensional animations.
MEMS+ for MATLAB and Simulink provides system-level analysis of MEMS systems, all the way from pure transient simulations to DC, DC transfer, modal and AC analysis.
- MEMS+ GUI in Simulink for automatic parametric model creation
- Fast system simulations
- Accurate multi-physics modeling
- Supports DC, DC Transfer, modal, AC and transient simulations
- User defined symbol pins and parameters
- MATLAB scripting interface for model import, manipulation and simulation directly from the MATLAB command line interface
MEMS+ System Simulation in Simulink
Control engineers and system architects commonly use Simulink from Mathworks to design MEMS control loops and signal processing circuits. In order to succeed, they require a fast and accurate model of the MEMS device in the Simulink simulation environment. MEMS system simulations are essential for controller and filter design and to predict yield sensitivity to manufacturing variations.
MEMS+ for Simulink lets you create the required device model by simply importing a 3-D model from MEMS+ Innovator. MEMS+ models can be inserted into larger systems that are either comprised of components from the standard Simulink library or from user defined components. MEMS+ models created in Simulink are based upon Coventor’s powerful MEMS+ model library, and go far beyond first order approximations. MEMS+ in Simulink provides real world answers to real world problems, like:
- What if other modes of motion interfere with the measurement of the desired mode to control or sense?
- Is the device control loop able to recover from severe shock?
- What if the device hits the stops?
- What if the device topology changes, or the dimensions change considerably?
MEMS+ automatically creates the symbol needed for system simulation in Simulink. All MEMS+ models in Simulink are inherently parametric. Any number of material, process or geometrical variables that are set as “exposed” in the Innovator schematic are also preserved in the related symbol that is created in Simulink. This means you never have to recreate the model in Simulink due to material, process or geometrical design changes.
In addition, Innovator’s MEMS modeling environment provides full user control over the number and names of the symbol pins visible in Simulink. MEMS+ for Simulink supports input pins for voltage, force, torque, pressure load, acceleration and angular rate, and output pins for capacitance, resistance, position and angle.
In this example, a user has exposed the following inputs for system simulation: the x and y acceleration of the reference frame (this is a 2-axis accelerometer) and the voltage for the separate stator combs and the proof mass (V_Rotors). For outputs, the user has exposed the 4 capacitances between the proof mass and the four stator combs. For purely diagnostic purposes, a point on the model has been exposed for direct application of a force input and a position output (M1x, M1y).
MEMS+ Simulink Design Flow
The MEMS+ for Simulink design flow includes the following steps
MEMS+ Device Simulation in MATLAB
MEMS+ for MATLAB is the ideal companion for rapid MEMS device design. It allows a MEMS designer to quickly narrow down an optimal MEMS device geometry, without requiring the mesh studies and parameter extraction effort needed when using conventional finite element analysis tools. MEMS+ for MATLAB also frees MEMS designers from constructing device physics models, such as mechanical response or capacitive force models, simply to understand the impact of a dimensional change in their design.
MEMS+ for MATLAB provides a variety of MATLAB scripts to facilitate model import, manipulation and simulation directly from within the MATLAB command line interface. MEMS+ scripts support DC, DC transfer, modal, AC and transient simulations without requiring any additional software (except the base MATLAB licenses).
Using MATLAB’s scripting language, designers can explore the design space to understand their design beyond idealized geometries and physics: What if the flexing structure has sidewall angles? Or is composed of multiple layers of different materials? Or is not a single straight beam, but composed of multiple serpentine sections? What if the electrostatic force has a strong fringing field component?
As an example, the figure to the right highlights the small-signal frequency response of an electrostatically driven ring gyroscope seen in the MATLAB interpreter. A MEMS+ gyroscope model was used in this model.