The Strydr Mission

“Those who walk alone have the strongest direction.”

Project Strydr was established by Kenneth Meyerson in 2019 for his undergraduate senior capstone project at Tufts University.  The scope of the original project focused on the development of an intelligent actuator from the ground up. Over the course of the year, Strydr grew from a solitary actuator to the foundations of a Lower Limb Exoskeleton.

Project Strydr™ was developed for fun to pursue a monumental challenge and is a product of its time and limitations.

Project Goals

Despite a strong overlap with the COVID-19 pandemic of 2020, the following proof of concepts were pursued to a proof of concept stage:

  • StryDrive™ Joint Actuator
  • StrydSense™ Controls
  • StrydLight™ Frame
StrydDrive™
StrydDrive™
StrydDrive™
StrydLight™
StrydLight™
StrydLight™
StrydSense™
StrydSense™
StrydSense™

Project Progress

09.2019 - 10.2019
Research and Planning
10.2019 - 02.2020
Actuator Design
03.2020
Design for Manufacturing
03.2020 - 04.2020
Frame Design
03.2020 - 04.2020
DSP Firmware Design
First meeting with project adviser, Mark Cronin-Golomb, on ‎September ‎17, ‎2019.

First concept discussion (September 2019)

First meeting with project adviser, Mark Cronin-Golomb, on ‎September ‎17, ‎2019.

Key features include lightweight composite frame, clamp mounting system, and initial torque transmission concept.

First actuator concept (September 2019)

Key features include lightweight composite frame, clamp mounting system, and initial torque transmission concept.

Breakdown of full project into sub-projects with friend, Michael Riegert.

High fidelity realization (October ‎2019)

Breakdown of full project into sub-projects with friend, Michael Riegert.

First prototype of composite carbon fiber frame with adjustable segment.

Frame Segment V1 (October‎ 2019)

First prototype of composite carbon fiber frame with adjustable segment.

Prototype of initial stackable planetary gearbox design.

Gearbox V1 (October ‎2019)

Prototype of initial stackable planetary gearbox design.

Schematic of generic electromyogram analog front end with adjustable gain.

Initial EMG AFP Schematic (November ‎2019)

Schematic of generic electromyogram analog front end with adjustable gain.

First working proof of concept cycloidal drive.

Gearbox V2 (December ‎2019)

First working proof of concept cycloidal drive.

Refined, user friendly cycloidal drive.

Gearbox V3 (December ‎2019)

Refined, user friendly cycloidal drive.

First assembly and testing of EMG and DSP.

EMG and DSP V1 (January ‎2020)

First assembly and testing of EMG and DSP.

Designed and Fabricated rotary encoder PCB for Gearbox.

Rotary Encoder PCB (January ‎2020)

Designed and Fabricated rotary encoder PCB for Gearbox.

Partial assembly with fixed length frame segment and tape substitute for nylon straps.

Knee to Ankle Assembly (January 2020)

Partial assembly with fixed length frame segment and tape substitute for nylon straps.

SMT installation of rotary encoder on professionally fabricated PCB.

Rotary Encoder Assembly (February 2020)

SMT installation of rotary encoder on professionally fabricated PCB.

Testing the range of motion with tape substitutes for nylon straps and fixed length frame segments.

Partial knee to ankle test assembly (January 2020)

Testing the range of motion with tape substitutes for nylon straps and fixed length frame segments.

Fiddlelock clasp allows mating from two directions and only separation in one.

Magnetically aligned nylon strap (February 2020)

Fiddlelock clasp allows mating from two directions and only separation in one.

Smooth and quiet motion. Transfer this to V6 for manufacturing.

Gearbox V5 (February 2020)

Smooth and quiet motion. Transfer this to V6 for manufacturing.

First telescoping clamp design suffered from dimensional accuracy preventing assembly.

Initial Telescoping Frame (February 2020)

First telescoping clamp design suffered from dimensional accuracy preventing assembly.

Features actuator, tube clamp, support brace, strap, passive ankle, and temporary foot platform.

Nearly complete knee to ankle assembly (February 2020)

Features actuator, tube clamp, support brace, strap, passive ankle, and temporary foot platform.

Input and filtered output with time shift from uncorrected filter group delay. In addition to a high common mode rejection ratio a digital 60 Hz filter attenuates powerline noise. Note: a mysterious 66 Hz signal is visible in the signal.

STM32 EMG acquisition and DSP (March 2020)

Input and filtered output with time shift from uncorrected filter group delay. In addition to a high common mode rejection ratio a digital 60 Hz filter attenuates powerline noise. Note: a mysterious 66 Hz signal is visible in the signal.