Brake Angle Position Measurement

laser

https://www.youtube.com/watch?v=2b-BE5c-cg4&ab_channel=MTIInstruments%2CInc.

using the Hall effect

2 pole sn magnetic disk is fixed on the actuator shaft

its position is detected by an ic sensor aligned to it with a small air gap between the magnet and the sensor

this is used to measure the angular position of a moving element by using a magnetic field instead of a physical brush or wiper

use a magnetically biased Hall-effect integrated circuit ic that senses the rotary movement of the actuator shaft over a set operating range

no moving contact so wear is eliminated

each Hall-effect sensor has a power supply and output terminal filter capacitor

the pedal circuit contains two independent Hall-effect sensor ics with filter capacitors at each of the power supply terminals and at each of the output terminals. the filter capacitors enhance and improve the immunity to electrical noise

the rotation of the actuator shaft changes the magnet’s position relative to the ic and the resulting flux density changes. it is converted to a linear output.

inductive type (for the following devices)

• consists of a sensor and activator

• the activator is typically made of mild steel and is mounted to or machined into the moving part of the application

• the sensor monitors the position of the activator as it moves across the sensor face

• this is a three-step process

1. it generates a magnetic field that penetrates the activator. this causes it to produce its own opposite field

2. the next coil stop generating its magnetic field and measures the activators induced field

3. the measurements are compared across the series of coils to calculate an absolute position of the activator

• unaffected by the presence of permanent magnets

inductive type - linear position sensor

https://www.gillsc.com/products/position-sensors/1484-linear-position-sensor/

• this sensor can measure angular, linear, and non-uniform travel

inductive type - rotary position sensor

https://www.gillsc.com/products/position-sensors/1498-rotary-position-sensor/

datasheet - https://www.gillsc.com/assets/Uploads/PD1498-Iss-6.pdf

• the output is a *pwm/voltage

• measures 360 degrees or fractional turn applications where the sensor output is configured across a portion of the measurement range

• non-contact design

inductive type - the dual cavity position sensor

https://www.gillsc.com/products/position-sensors/1356-dual-cavity-sensor/

• uses induction technology with two coils measuring the position of a unique metallic target activator

• thicker activator prongs produce a stronger field

• sensor output varies symmetrically (~2.5v)

• introducing an activator into the positive coil sends the voltage up and vice versa

• each coil can also be used independently and produces a separate output allowing for the monitoring of two separate movements with a single sensor

• non-contact two-part design

• the unique arrangement allows for a wide range of linear or angular motion to be monitored with various output characteristics by changing the shape of the activator

measurement range

0° to 360° (configurable)

- linear (range governed by activator shape)
- rotary: +/-45°

outputs

- analog: 0-5.5V DC (unless limited by V supply)
- *pwm: 1KHz
- serial RS485, 19.2K 8N (serial communication method for computer and devices)
- switch (digital output)

analog: 0-4.2V DC

accuracy

analog: +/-0.5° over the temperature range

+/-3% over the temperature range

resolution (the smallest change it can detect in the quantity that it is measuring)

10 bit over the configured range

10 bit

sample rate (sensing elements per second)

1KHz

1KHz

supply voltage

-4.8V to +32V DC

+6V to +30V DC

supply current

<25mA without comms

<10mA

operating temperature

-40° to +85°C (32V DC max)
-40° to +125°C (14V DC max)

-40° to +85°C (standard)

ingress protection

IP67

IP67

price

£97 + shipping

potentially free ???