Projects

  • Permanent Magnet AC Motor Driver

  • VFD for Consumer Induction Motors

  • CNC Machine

  • ARManda - a 4DOF desktop robotic manipulator

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AS5048A Magnetic Encoder and STM32

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This past week I began to write the controller firmware - mainly playing with the AS5048A angular position sensor from AMS. Here is the datasheet .  This sensor will be used to get the rotor position and then compute the resulting electrical angle for the Clarke/Park transforms and also it will be used to find rotor speed for the out loop.  I will be using an STM32F446 board to run the loop as it has a high clock speed. The AS5048A sends its measurements over SPI. Below is the read package sent from the sensor: We get 14 bits of position data - aka 16384 ticks per revolution, or a resolution of 0.0219 degrees. I wrote this read() function that sends the SPI command package and reads the resulting response: uint16_t read(uint16_t registerAddress) { uint16_t command = 0x4000; // PAR=0 R/W=R uint8_t RxBuff[2]; uint8_t TxBuff[2]; command = command | registerAddress; command |= (uint16_t) (spiCalcEvenParity(command) << 0xF); TxBuff[0] = command >> 8; TxBuff[1] = co
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Pseudo-FOC Controller - Simulations and Inital

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As a part of my FOC controller, I am developing an intermediate project - the  Pseudo-FOC Controller. This post will introduce the theory, simulations, and an initial prototype of the project. At its core, this controller uses sinusoidal commutation, which is being implemented through the inverse Park and Clarke transforms. Project Goals The goals of this project are listed below: Control torque, speed, and position of a PMSM - specifically for gimbal and drone grade motors Develop a PCB for the controller Develop auto-tuning algorithms for controller gains Develop an auto-calibration sequence for the rotor position sensor BLDC vs PMSM A key point of confusion is motor classification of permanent magnet machines - specifically between Brushless DC Motors  (BLDCs) and Permanent Magnet Synchronous Motors (PMSMs). In my experience/readings, the differing factors is in their back-emf profile: BLDCs having a trapezoidal BEMF and PMSMs having a sinusoidal BEMF. It is also important to note t
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Revised CNC Mill Design

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In the last post I fixed some of the clearance and parts issues for the x-axis assembly for the CNC mill. I since applied these same changes to all axes and dialed in most of the components. Here is a image of the full system:  Version 2 of the CNC mill design. The entire assembly weighs 48 kg which is on the lighter side. To fix this I plan on casting epoxy granite around the y-axis base to add both mass and damping properties.  The work area is: X travel: 240 mm Y travel: 180 mm Z travel: 110 mm Parts Each of the axes use SFU1204 ball screws, the only difference being the length: 500 mm on x, 400 mm on y, and 300 mm on z. Similar to this, all axes use HGR25 linear rails (a pair) and 4 HGH25-CA linear bearings (2 per rail). Again the only difference is the lengths: 500 mm on x, 400 mm on y, and 300 mm on z. For the spindle I plan on using a 1.5 kW 110 V air cooled spindle and a VFD ( found here ). I modelled the dimensions in Solidworks (as seen above). The motors are just NEMA 27s, h
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