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Dephy Actuator Package

The Dephy Actuator Package is a turn-key solution for people who want to test FlexSEA's capabilities or quickly design a prosthetic limb. The Package consists of a custom brushless motor integrated with a FlexSEA-Rigid circuit and a minimalist enclosure, pre-loaded embedded software, and a full suite of high-level software and test scripts.


  • Fully integrated brushless motor (BLDC), power electronics and control logic
  • Plug and play solution: no programming needed for most applications
  • Cross-platform graphical user interface and full suite of C/C++, Python and MATLAB demo scripts
  • Built-in high-performance controllers: current, position, impedance, and voltage.
  • Built-in sensors and interfaces: 6-axis IMU, voltage, current, temperature, strain gauge amplifier, etc.
  • Communication: Bluetooth Classic EDR, USB, RS-485, SPI, UART and I2C
  • Safety features: battery I²t, motor I²t, voltage limits, temperature


Table 1. Motor

Mass 230 g
Terminal resistance 186 mΩ
Terminal Inductance 138 µH
Torque Constant 56 mNm/A
Diameter 87 mm
Length 17 mm
Rotor inertia 1E-4 kg m2

Table 2. Housing

Mass 50 g
Material 7075-T6 Aluminum
Finish Black anodization

Can be customized and/or engraved. Ask during the quoting process.

Table 3. Embedded System

Mass 41 g
Voltage 20-50 V (5s-12s LiPo)
Commutation type 4-quadrant Field-Oriented control (4Q FOC)
PWM frequency 20 kHz
Max continuous motor current 10 A (Note 1)
Peak motor current 30 A (Note 1)
High level controller STM32F427 180 MHz Cortex-M4 with floating-point unit (FPU)
IMU MPU-9250 6-axis (3-axis accelerometer, 3-axis gyroscope) (Note 2)
Bluetooth RN-42 Class 2 EDR Bluetooth module
Strain-gauge amplifier One full-bridge channel, 5V excitation Gain = 203
Motor encoder Absolute magnetic encoder, 14-bits
Current sensing and control Motor: 3-ch 12-bits sensing, 10kHz PI controller
Battery: ±20A, 900Hz bandwidth, 12-bits
Safety protections (HW) 52V TVS, 10A slow-blow fuse
Intrinsic sensors Battery voltage, intermediate voltage, +5V bus, temperature, etc.

(1) Higher currents can be used with a heatsink. Multiply reported and commanded currents by 0.40 to obtain Q-axis current.

(2) Magnetometer disabled by software – overpowered by the motor’s magnetic field

Quick start guide

Below are high level instructions and resources to get users started, as well as additional information to facilitate troubleshooting.

  1. Get the device powered up. This can be accomplished using a power supply or a USB cable. Then turn the device on by pressing the power button.
  2. Install and run the Plan GUI.
  3. Communication between your computer and the Actuator Package can be established over USB or Bluetooth.
  4. The connection can be validated by streaming data.
  5. Plan can also be used to control motors.
  6. With those functionalities verified, the demo scripts can be run. This allows the user to bypass the GUI and can serve as a template for future code in your target language.
  7. Before using the scripts make sure to read Actuator Package Software User Guide

Example Applications

Tips, Tricks & Best Practice

  • Before plugging your ActPack, please review the Important Safety Warnings page.
  • To get started on software read the Actuator Package Software User Guide
  • Prevent USB connector problems:
    • Make sure that the through-hole support legs are soldered to the PCB (one CM forgot to do it). It greatly reduces the chances of ripping the connector. Contact Dephy if you need assistance with this.
    • Whenever possible connect & disconnect the computer side of the USB cable (USB A), not the ActPack side (USB Micro B).
    • If you use USB other than for a bench-top experiment, you must provide strain relief on the cable. To be clear, people have been breaking them on benchtops too, so please be extra careful.
  • Having USB connected will prevent a full power-cycle, even if you turn the module on & off with the push-button. After reprogramming one or more microcontrollers always do a true power cycle.
  • When using Bluetooth we recommend waiting 15s between powering the circuit and starting a stream (from the GUI or the scripts). The RN-42 boots in a slow mode and transitions to fast after 10s. Starting a stream too soon can create issues.
  • If there are Bluetooth connection problems with Windows, try restarting the Windows “Bluetooth Support Service” before rebooting.

Additional Resources

dephyactpack.txt · Last modified: 2020/08/27 13:43 by lmooney