"I'll Go Where It's Dangerous"... Haengdok, the Robot Dog Guarding Ulsan CLX

Patrolling with Gas Detectors and Thermal Cameras
Early Deployment in Hazardous Areas
Filling Safety Blind Spots
Expansion Planned by 2027; Integrated Surveillance Under Consideration

A robot with a yellow body and four legs. Cameras and various sensors are attached to its "head." Its brisk gait strides between complicated networks of pipes and massive equipment, looking unmistakably like a dog. However, the mission of this “dog” is to inspect the safety of the factory.

The quadruped robot 'Haengdok' is patrolling between production facilities at SK Innovation Ulsan Complex (Ulsan CLX). SK Innovation

This is “Haengdok,” the quadruped robot working at SK Innovation Ulsan Complex (Ulsan CLX). Its name combines “Happiness,” a core value of SK’s management philosophy, with the English word “dog.”

The official model for Haengdok is “Spot,” a quadruped robot developed by Boston Dynamics in the United States. Haengdok was deployed at Ulsan CLX in October 2022 to take charge of inspecting and patrolling facilities in areas that are difficult for people to access.

The need for Haengdok stems clearly from the sheer scale of Ulsan CLX. The Ulsan CLX site covers 8.26 million square meters. If you connected all the plant’s piping, it would stretch about 600,000 kilometers—enough to circle the Earth roughly 15 times or make a journey to the moon and come back more than halfway.

Given this vast expanse of production facilities, it is impossible for humans to perform thorough inspections without gaps. In particular, during nighttime, in bad weather, or in areas where gas leaks might occur, it is burdensome for workers to approach, and inspection gaps can arise. Haengdok steps in to check the site before people enter, helping to minimize the risk exposure of workers and fill in blind spots that human patrols might miss.

The quadruped robot "Haengdok" is moving and inspecting areas dense with pipes and facilities inside Ulsan CLX. SK Innovation

Haengdok’s primary stage is around major production facilities such as the No.2 Fluid Catalytic Cracking Unit (No.2 FCC). Carrying a gas detector and thermal imaging camera, it automatically patrols the site according to a set schedule. It acts as a “four-legged safety officer,” enabling detection of temperature changes or gas leaks without humans having to approach the equipment directly.

It does much more than simply walk around the factory once. The data it accumulates—on temperature, vibration, and gas concentration—during patrols can be used to analyze changes in facility status. By detecting abnormal signs in advance, it forms the foundation for predictive maintenance that allows action to be taken before failures occur.

Currently, Haengdok operates autonomously on a predetermined patrol schedule. Looking ahead, the plan is to enhance its functions so that when an anomaly alarm is triggered at a facility, Haengdok can be dispatched to the site, assess the situation, and deliver its analysis to managers and the system in real time.

A sign reading "Beware of Dog" is posted in front of the dedicated storage and charging space for the quadruped robot "Haengdok" installed at Ulsan CLX. SK Innovation

The factory even has a dedicated “house” for Haengdok. Shaped like a typical doghouse, it features a “Beware of Dog” sign at the entrance. However, this robotic guard dog is not alerting people, but rather tasked with watching out for abnormal signals from factory equipment.

As of the article’s publication date in September 2026, there is only one Haengdok operating at Ulsan CLX. SK Innovation is considering expanding the use of robots by the first half of 2027, although the specific scale of this expansion is still under internal review.

In the long term, the goal is to go beyond simply increasing the scope of a single Haengdok unit. SK Innovation envisions developing an integrated surveillance system that analyzes information collectively from quadruped robots, drones, and intelligent CCTV cameras within a single platform.

The traditional method, where humans patrolled sites at set times to check for anomalies, is giving way to a system in which robots and various sensors fill in the gaps. As Haengdok moves throughout the 600,000 kilometers of piping laced through every corner of Ulsan CLX, its role is expected to grow accordingly.

This content was produced with the assistance of AI translation services.