Accelerometer

Dynamic model of MEMS accelerometer.

blockType: AcausalElectricPowerSystems.Sensors.Accelerometer

Path in the library:

/Physical Modeling/Electrical/Sensors & Transducers/Accelerometer

Description

Block Accelerometer implements a dynamic accelerometer model of microelectromechanical systems (MEMS). When set by default for the parameter Output type meaning Voltage level The accelerometer outputs an output voltage proportional to the amount of acceleration transmitted through the non-directional port R. The output voltage is limited by the maximum and minimum output voltage values you set.

The block also has an alternative parameter value Output type — PWM duty cycle. When this value is selected, the output signal of the unit is a PWM signal with a fill factor proportional to the measured acceleration. The change in the fill factor can be limited to a specified range.

If desired, you can simulate the dynamics of the sensor by setting the parameter Dynamics value Model sensor bandwidth. Turning on the speaker adds a first-order delay between the angular velocity displayed on the R port and the corresponding voltage applied to the + and − ports.

When starting a simulation using a fixed-step solver or when generating code for software and technical testing, it is recommended to set the parameter Dynamics value No dynamics - Situable for HIL because this avoids the need to use a small step in the simulation time at high sensor throughput.

Ports

Conserving

# R — the transfer port
mechanics

Details

A non-directional port connected to the translational port of the accelerometer.

Program usage name

translational_flange

# + — positive port
electricity

Details

A non-directional port connected to the positive terminal of the accelerometer.

Program usage name

p

# − — negative port
electricity

Details

A non-directional port connected to the negative terminal of the accelerometer.

Program usage name

n

Parameters

# Output type — type of output value
Voltage level | PWM duty cycle

Details

Select one of the following options to determine the type of output value:

Voltage level — the amplitude of the output voltage is proportional to the measured acceleration. This value is set by default.
PWM duty cycle — the fill factor (turn-on time divided by the total pulse duration) is proportional to the measured acceleration.

Values	`Voltage level` \| `PWM duty cycle`
Default value	`Voltage level`
Program usage name	`output_type`
Evaluatable	Yes

# Sensitivity — sensitivity
mV/gn

Details

The change in the output voltage level per unit of acceleration change in the absence of output signal limitation.

Dependencies

To use this parameter, set for the parameter Output type meaning Voltage level.

Units	`mV/gn`
Default value	`1000.0 mV/gn`
Program usage name	`sensitivity`
Evaluatable	Yes

# Output voltage for zero acceleration — output voltage at zero acceleration
V | uV | mV | kV | MV

Details

The output voltage of the sensor at zero acceleration.

Dependencies

To use this parameter, set for the parameter Output type meaning Voltage level.

Units	`V` \| `uV` \| `mV` \| `kV` \| `MV`
Default value	`2.5 V`
Program usage name	`V_zero`
Evaluatable	Yes

# Maximum output voltage — Maximum output voltage
V | uV | mV | kV | MV

Details

The maximum output voltage of the sensor, which determines the maximum positive acceleration measured by the sensor.

Dependencies

To use this parameter, set for the parameter Output type meaning Voltage level.

Units	`V` \| `uV` \| `mV` \| `kV` \| `MV`
Default value	`4.0 V`
Program usage name	`V_max`
Evaluatable	Yes

# Minimum output voltage — minimum output voltage
V | uV | mV | kV | MV

Details

The minimum output voltage of the sensor, which determines the maximum negative acceleration measured by the sensor. The default value is 1 V.

Dependencies

To use this parameter, set for the parameter Output type meaning Voltage level.

Units	`V` \| `uV` \| `mV` \| `kV` \| `MV`
Default value	`1.0 V`
Program usage name	`V_min`
Evaluatable	Yes

# Dynamics — dynamics
No dynamics - Situable for HIL | Model sensor bandwidth

Details

Select one of the following options for modeling sensor dynamics:

No dynamics - Situable for HIL — do not simulate the dynamics of the sensor. Use this value when running a fixed-step simulation or when generating code for software and hardware testing, as this avoids the need for a small simulation step with high sensor throughput. This value is used by default.
Model sensor bandwidth — simulate sensor dynamics using a first-order delay approximation based on the parameter value Bandwidth. You can control the initial delay condition by specifying the target value of the variable Measured acceleration.

Values	`No dynamics - Situable for HIL` \| `Model sensor bandwidth`
Default value	`No dynamics - Situable for HIL`
Program usage name	`dynamics_model`
Evaluatable	Yes

# Bandwidth — bandwidth
Hz | kHz | MHz | GHz

Details

Defines the bandwidth by level 3 dB for the measured acceleration, assuming a first-order time constant.

Dependencies

To use this parameter, set for the parameter Dynamics meaning Model sensor bandwidth.

Units	`Hz` \| `kHz` \| `MHz` \| `GHz`
Default value	`3.0 kHz`
Program usage name	`bandwidth`
Evaluatable	Yes

# Duty cycle sensitivity (percent per unit acceleration) — sensitivity of the fill factor
1/gn | s^2/m | s^2/cm | s^2/ft | s^2/in | s^2/km | s^2/mi | s^2/mm

Details

Change of the fill factor per acceleration unit. The fill factor is expressed as a percentage of the PWM period.

Dependencies