Human in the loop

I build robots and random mechanisms.

Mostly firmware and motion control.

Motors & actuators (a lot of actuators).

The occasional over-engineered gadget.

About

Steven Zhai

I am a mechanical engineering student at Purdue. I love exploring mechanisms invented hand in hand with their materials, including compliant mechanisms and biomimetics. My current research is on robotic muscles, specifically dielectric elastomer actuators. They are close cousins of the HASEL actuators already in industry. They peak near 580 W/kg (about double human muscle) and pull joints through tendons with no gearboxes or linkages.

My newer fascination is within the industrial sector. At Pratt & Whitney, I worked with ABB robots and noticed two issues up close. First, how slowly a repair cell comes to life. Second, how quickly expertise is lost.

Why deployment is SO SLOW

A solutions company consults first, then months go to shipping and installing the hardware, followed by training and certifying the crew. After deployment, every breakdown waits on an outside repair, adding to the 27 hours a month large plants already lose to unplanned downtime. All told, it costs four to five times the arm's price. Even then, no digital twin yet fuses live data from every brand of machine on the floor, so people still make the calls.

Why expertise walks out the door

Veteran on-shop staff averages 9.6 years of tenure, young hires 2.7, so expertise retires before it transfers. An exoskeleton that records a veteran's motions could replay them to guide the next hire, passing down know-how the veteran never had to write down. This could also bring down the cost of training and certifying new staff.

I want to build cheaper, task-oriented robots. For most factory tasks, the right form is rarely humanoid.

Why actuators set the price

Off-the-shelf modular actuators already let integrators snap custom robots together, but actuators are a third of a robot's value. Cheaper, task-matched modules would cut both the price and the custom engineering behind every deployment.

My research attacks the actuator problem from two sides. One is cost: developing affordable, high-performance artificial muscles from my lab. The other is building up to hybrid joints/arms that pair motors with muscles that sense their own motion. I am motivated to join an early-stage team shipping affordable, task-shaped robots, starting from actuator R&D. Interested in my ponderings? Say hi below.

Experience

Pratt & Whitney Shanghai Engine Center logo

Repair Engineering Intern · Pratt & Whitney Shanghai Engine Center

May 2026 – Aug 2026

Shanghai, China

A summer inside a commercial engine overhaul shop. Root cause studies, first article inspections, and the paperwork that proves a repair can be trusted.

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Bionic Interfaces Prototyping Lab, Purdue ME logo

Undergraduate Researcher · Bionic Interfaces Prototyping Lab, Purdue ME

Jan 2026 – Present

West Lafayette, IN

Fabrication and COMSOL modeling for a soft-actuator lab. 100+ devices coated, measured, and matched to simulation.

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RAAD Lab, Purdue ME logo

Undergraduate Researcher · RAAD Lab, Purdue ME

Jan 2026 – May 2026

West Lafayette, IN

Designed and bench-tested the servo valve node that lets a soft bellow array reconfigure on one air line.

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AIDA3, Purdue's aviation AI center logo

Flight Systems Researcher · AIDA3, Purdue's aviation AI center

Jan 2025 – Dec 2025

West Lafayette, IN

Taxiway graphs, a runway geofence, and hangar flight tests for an autonomous cargo plane.

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Lavazza at Purdue logo

Barista · Lavazza at Purdue

Jan 2025 – Present

West Lafayette, IN

Espresso and latte art at a campus café. Pouring a clean rosetta is a process-control problem. I treat it like one.

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PURT logo

Lead Software Researcher · PURT

Jan 2025 – Aug 2025

West Lafayette, IN

Led the software team. Owned the ROS 2 pipeline, the RRT* planner, and the land-or-abort landing code.

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Projects

Personal

Class

Get in touch

Have a question or want to collaborate on a project? Send me a message and I'll get back to you!