Hall-Effect Rotary Encoder

Four-element Hall-effect rotary encoder

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Libraries:
Simscape / Electrical / Sensors & Transducers

Description

The Hall-Effect Rotary Encoder block models a 360° rotary position sensor using four Hall elements equally spaced under a magnetized, rotating magnet. The elements generate four sinusoidal waveforms.

Equations

The voltages between the elements of the rotary encoder are described by the equations:

$$v_x=V_{x0}+A_x\cos (\theta )$$

$$v_y=V_{y0}+A_y\cos (\theta -\frac{\pi }{2}+\beta ),$$

where:

• v_x is the voltage between elements x_p and x_n;

• v_y is the voltage between elements y_p and y_n;

• A_x and A_y are the voltage amplitudes for the x and y axes that reflect the sensitivity mismatch;

• V_x0 and V_y0 are the voltage offsets for the x and y axes;

• β is the quadrature error.

The block uses this equation to decode the angle:

$${\theta }_{out}=\arctan \left(\frac{v_y}{v_x}\right).$$

Variables

To set the priority and initial target values for the block variables before simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. You can specify nominal values using different sources, including the Nominal Values section in the block dialog box or Property Inspector. For more information, see System Scaling by Nominal Values.

Ports

Conserving

R — Rotational velocity for the sensor positive probe

mechanical rotational

Mechanical rotational conserving port associated with the sensor positive probe.

C — Rotational velocity for the sensor negative probe

mechanical rotational

Mechanical rotational conserving port associated with the sensor negative (reference) probe.

yp — y-axis positive Hall field

electrical

Electrical conserving port associated with the y-axis positive Hall field.

Dependencies

This port is visible only if you select Electrical connections for the Output interface parameter in the Parameters settings.

yn — y-axis negative Hall field

electrical

Electrical conserving port associated with the y-axis negative Hall field.

Dependencies

This port is visible only if you select Electrical connections for the Output interface parameter in the Parameters settings.

xp — x-axis positive Hall field

electrical

Electrical conserving port associated with the x-axis positive Hall field.

Dependencies

This port is visible only if you select Electrical connections for the Output interface parameter in the Parameters settings.

xn — x-axis negative Hall field

electrical

Electrical conserving port associated with the x-axis negative Hall field.

Dependencies

This port is visible only if you select Electrical connections for the Output interface parameter in the Parameters settings.

Output

Angle — Rotational angle

physical signal

Physical signal output port for the decoded position in terms of the rotational angle of the magnetic field in the x-y plane.

Dependencies

This port is visible only if you select Decoded angular position for the Output interface parameter in the Parameters settings.

Parameters

X-axis voltage amplitude — x-axis voltage

2.5 V (default)

X-axis voltage amplitude, in V.

Y-axis voltage amplitude — y-axis voltage

2.5 V (default)

Y-axis voltage amplitude, in V.

X-axis voltage offset — x-axis voltage offset

0 V (default)

Potential difference in the electric current flow through the electric conductor in the absence of external magnetic field on the x-axis, in V.

Y-axis voltage offset — Y-axis voltage offset

0 V (default)

Potential difference in the electric current flow through the electric conductor in the absence of external magnetic field on the y-axis, in V.

Quadrature error — Quadrature error

0 deg (default)

Amount of quadrature error. Quadrature switching can decrease offset errors.

Output interface — Interface for decoded information

Electrical connections (default) | Decoded angular position

Port interface for decoded information.

Dependencies

The yp, yn, xp, and xn conserving ports are visible only if you select Electrical connections for the Output interface parameter.

The Angle physical signal port is visible only if you select Decoded angular position for the Output interface parameter.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2019b