Robotics startup cofounder explains why legs aren’t essential for most robots

Why Most Robots Don’t Need Legs: Insights from Diligent Robotics CTO Vivian Chu

Meet Moxi: The Hospital Helper

Vivian Chu, cofounder and CTO of Diligent Robotics, is behind Moxi — a wheeled robot built to support medical staff with routine duties like delivering lab samples and supplies. Rather than imitating a futuristic humanoid, Moxi focuses on practicality: a head, one arm, and wheels.

Chu calls it the “minimum viable humanoid” — not a conversational machine powered by advanced AI, but a purpose-driven tool. With more than 90 robots in over 25 hospitals, Moxi has completed 1.2 million deliveries, which the company estimates has saved staff nearly half a million hours.

Why Wheels Beat Legs

While companies like Tesla and Figure.AI promote humanoid robots with legs, Chu insists that wheels are sufficient for most applications. Hospitals are ADA-compliant, with ramps and elevators, making wheels safer, more stable, and easier to manage. If a wheeled robot shuts down, staff can simply move it aside.

Legged robots may have uses in disaster recovery or in homes with stairs, but for daily hospital workflows, wheels remain the most effective choice.

Designing Specifically for Hospitals

Early investors questioned why Moxi needed an arm. Chu explained that without one, hospitals would need costly retrofits for elevators and doors. With its arm, Moxi can press buttons independently, avoiding expensive infrastructure changes.

The head also serves a purpose. It helps communicate intent, as people can infer a robot’s next move from its gaze. Sensors in Moxi’s head provide perception and interaction cues, ensuring staff understand its actions.

Why Healthcare Became the Focus

Chu and cofounder Andrea Thomaz chose healthcare after interviewing and shadowing medical professionals. They found nurses often spend up to 30% of their time fetching supplies, with less than 30% dedicated to direct patient care. Robots like Moxi return valuable time to staff, improving patient outcomes.

Measuring Moxi’s Impact

Hospitals evaluate Moxi by time and steps saved. For example, in one system, all telemetry box deliveries across three large facilities are now handled by the robot, eliminating the need for human staff to run them. Across deployments, Moxi’s 1.2 million deliveries have significantly reduced staff workload.

Investors and the Future of Robotics

Initially, investors questioned why Moxi had one arm; now they ask why it doesn’t have two. Chu says added dexterity is part of the future roadmap, along with deeper integration into hospital record systems and new task capabilities.

She cautions against the hype around legged humanoids. The key, she says, is designing robots that solve workflow problems and truly give people their time back.

The Battery Challenge

Even as hardware becomes more affordable, battery life remains a bottleneck. Moxi can run up to 16 hours with smart charging, but more powerful computing demands more energy. By contrast, some humanoid robots operate for only 90 minutes. Hospitals, Chu notes, need safe, long-lasting batteries to trust robotic systems.

Looking Ahead

Diligent Robotics is working on enhancing Moxi’s dexterity to handle more complex tasks like assembling case carts or managing larger supply chains. The company is also exploring ways to integrate robots directly with hospital records, so tasks could be triggered automatically by patient admissions.

For Chu, the future of robots is not about legs but about smart, efficient machines on wheels that seamlessly fit into human environments.