High-speed robot bicycle can jump over obstacles

A new robotic platform capable of moving at high speeds, jumping over high obstacles and maintaining balance, even on a single wheel has been developed by a team of researchers from the Robotics and AI Institute (RAI).

The robotic platform, dubbed Ultra Mobility Vehicle (UMV), is a two-wheeled robot that can execute dynamic maneuvers similar to those performed by skilled human cyclists.

The UMV. (A) Diagram of the UMV, a bicycle-based robot with five actuated degrees of freedom [Links (green) and subcomponents (purple)]. It has steering and rear-wheel drive actuators for basic ground mobility. The design concentrates most of the robot's mass in the Head, which connects to the Bike through a spatial linkage. This linkage consists of the Neck and two tie rods. Powerful actuators in the Head work through the linkage to let the robot "throw" its mass around, enabling dynamic behaviors. Composite images of (B) a front flip, demonstrating high pitch angular momentum and modulation of inertia via body tucking, (C) rear-wheel hopping, where the robot maintains balance like a single-legged hopper, (D) an autonomous table jump sequence, where the robot accelerates, vaults onto a 1-meter platform, traverses it, and lands stably. Source: Bokser, et al.

"A fundamental challenge in robotics is balancing robots that move with speed while being terrain agnostic," the team explained. "Wheels provide efficiency while legs handle stairs, curbs, and rough terrain. It becomes a trade-off of how complex, expensive, and energy-hungry you want your robot to be versus how much you want the robot to be able to handle the unknown while it moves around. We kept coming back to the fact that trial cyclists and mountain bikers bridge this gap every day."

Inspired by the acrobatics performed by human cyclists on two wheels — riding fast on different terrains, hopping over obstacles and temporarily balancing on a single wheel the team sought to develop a robot with two wheels and a frame that could mimic similar movements.

"We asked: what if we took that same form factor and gave it the ability to dynamically reposition its mass — the way a rider shifts their body — using a compact articulated mechanism and modern learning-based control?" the team explained. "Our primary objective was to show that you don't need a dozen degrees of freedom to achieve athletic robotic motion. We wanted to demonstrate that a bicycle-based robot with only five actuated degrees of freedom could drive at high speed, balance dynamically, and jump onto obstacles that are taller than the robot itself."

The result is the UMV, which is a robotic bicycle featuring two in-line wheels, a steering frame and a rear-wheel drive configuration. This design includes a motor that propels the robot by sending power to the rear wheel, while the front wheel is only responsible for steering.

The researchers noted that the UMV relies on mechanical simplicity coupled with advanced control to efficiently navigate in diverse environments. Its heavy “head” unit — which houses batteries, compute and actuators — is connected to the bicycle frame through a powered neck and tie rods, enabling the robot to shift its mass to crouch, jump or balance dynamically, mimicking a rider’s movements.

The UMV achieved agility comparable to legged robots while using just five actuated degrees of freedom. The UMV’s bicycle-based design allows for dynamic behaviors — such as driving, balancing, wheelies, hopping, jumping, flipping and maneuvers like shimmy-turns — without reaction wheels or kickstands, relying instead entirely on dynamic control.

All of these movements are produced by reinforcement learning trained in simulation and transferred directly to the real robot, enabling adaptive behaviors. The UMV can jump 1 m (130% of its height) and reach 8 m/s, demonstrating performance on par with more complex legged platforms.

The team envisions that the UMV could one day be used in applications such as urban delivery, rough-terrain transport and inspection in constrained spaces.

An article detailing the system, “System Design of the Ultra Mobility Vehicle: A Driving, Balancing, and Jumping Bicycle Robot,” appears in the journal arXiv.

For more on the robot, watch the accompanying video that appears courtesy of RAI.