Microchip Technology Inc

Angular Position Sensor Control System

The need for angular position sensing has increasingly become important as this capability is needed for a range of applications from brushless DC motor control to pedal positioning control to steering angle sensing control to human-machined interface (HMI) buttons as rotary switches. The angular position sensor control system analyzes the data received from sensors and determines the appropriate angular rotation for the system. Four primary sensing technologies are deployed to measure the angular position within automotive applications—optical sensors, potentiometers, magnetoresistive (MR) sensors and hall-effect sensors.

Design Considerations
  • Flexible sensor interfaces
  • Performance oriented microcontrollers for supporting advanced mathematical algorithms and enabling parametric compensation for distributed sensors
  • Robust communication interfaces
  • The PIC® microcontrollers and dsPIC® digital signal controllers are performance-oriented with a broad array of on-chip peripherals which provide the system designer with versatile options to support the sensing methodology being utilized. For example, a system designer might choose a PIC12 or PIC16 device for a low-end rotary switch, whereas, the PIC18, PIC24 or dsPIC33 devices might be utilized in a steering angle sensor design. Angle sensing is calculated from the sensor inputs.
  • Microcontrollers with on-chip EEPROMs provide the system designer alternatives for storing compensation values in the data EEPROM that can be used to calculate operational requirements for the current environmental conditions which the electronic control module are experiencing.
  • With the harsh environmental conditions, the robust designs of the PIC microcontrollers and dsPIC digital signal controllers make them excellent choices for the system designer in their quest to minimize system costs and chip component count.
  • With various on-chip peripherals to support various communication protocols, the system designer is able to choose a microcontroller to interface with in-vehicle networks such as CAN and LIN. For example, in a steering angle sensor application, the CAN bus is utilized to transfer real-time data regarding rotational speed and steering angle position reliably to the Electronic Stability Control Module. In the steering angle sensor application, the LIN bus is utilized to transfer data to the turn signal indicator. Microcontrollers supporting both CAN and LIN in the steering angle system increases reliability through the reduction of the components while enabling the system designer to lower the system costs and reduce the vehicle weight.
  • The 16-bit microcontroller and digital signal controllers are capable of AUTOSAR support. LIN and CAN transceiver options are available to the system designer for the physical layer interface requirements.
Development Tools