Skip to main content

Underwater Walking Robot - Crabster CR200

The underwater walking robot named Crabster CR200 is developed by researchers at the Korean Institute of Ocean Science and Technology (KIOST). The task of the Crabster CR200 is to inspect the seabed structure and shipwrecks off the coast of Korea Peninsula. This summer the robot will explore wrecks despite the powerful surge of tidal current.

The CR200 has 6 legs for mechanical contact with seabed and like its biological cousins, the forward 2 legs also work as robotic arms for underwater manipulation. It can pick up objects and store them inside a frontal compartment. The Crabster is equipped with 10 optical cameras and a long-range scanning sonar which scans up to 200 m (650 ft) away, so the robot is able to perform the precise inspection and manipulation in a low visibility environment.

The CR200 endures the tidal current by controlling the posture of its body and legs. Researches used computer simulations to streamline the robot's main shell, that improves the stability:

The numerical simulations were performed for the evaluation of current loads acting on the CR200 with a variety of incident angles using ANSYS-CFX package. The Reynolds-averaged Navier-Stokes equations were solved to simulate the fluid flow around the CR200 to calculate forces and moments induced by incoming current with angles.

The robot is powered through an external power cable and it can operate under water for more than 24 hours

Let us see, how its first major underwater test looked. Test took place at KIOST's South Sea Research Institute, located in Geoje City, South Korea. The robot's weight is 600 kg (1322 lb) and in total it is 2.42 m long, 2.45 m wide, and 2 m high (7.9 ft x 8 ft x 6.5 ft). The robot and its remote control station were designed to be easily transported in a pair of shipping containers.

Four people remotely control the Crabster CR200 from the control station inside the shipping container. The pilot controls the robot's walking and posture. Manipulators, cameras, and lights are controled by a co-pilot. A sonar engineer monitors the scanning sonar and other sensors, while a navigator plans its movement and keeps track of its position.
Robot's equipment is shown in the figure below. It's equipped with i.a. an acoustic camera, acoustic doppler current profiler, high resolution scanning sonar, and several contact force sensor.

The Crabster performed well during its first dive. Bong-Huan Jun, a principal research scientist at KIOST, said:

I was very excited, but on the other hand I was nervous during the test. There are many mechanical and electrical parts inside the legs, such as the electrical motors, reduction gears, amplifiers, and interface boards. If even one sealing is faulty, seawater will enter the container which could cause shorts and corrosion. Any single minor problem would require a long time to fix.

Here is the video of the first major underwater test at KIOST's South Sea Research Institute:

The Crabster CR200 team includes researchers from five universities:

  • Seoul National University of Science and Technology developed the gait algorithm, using Little Crabster as a test-bed;
  • Mokpo National University performed hydrodynamic analysis and estimation of current load on the robot;
  • Chungnam National University helped with optimal joint path planning for swimming motion;
  • Pukyong National University studied how to implement fault tolerance gait;
  • Kookmin University contributed with numerical modeling and simulation of the robot.

The video below shows the robot's standing-up posture. The Crabster CR200 is a really big robot.


Anonymous said…
Nice mechatronics project. Very complex from technical point of view.

You might also like

    Popular posts

    What is Mechatronics?

    Mechatronics definition Mechatronics is a synergistic combination of precision engineering, electronic control and mechanic systems. It is the science, that exists at the interface among the other five disciplines: mechanics, electronics, informatics, automation, robotics. It is one of the most dynamically developing fields of technology and science. The word 'mechatronics' appeared for the first time in Japan in 1969. mechatronics = mecha nics + elec tronics + computing

    Ascento - The Two-Wheeled Jumping Robot

    All-terrain capabilities are required to extend beyond flat surfaces the application range of wheeled robots. First think is four or six-legged robots which have been well known for years. Nowadays, thanks to more and more perfect gait algorithms, the two-legged (bipedal) robots appears more and more often. ETH Zürich students combine the advantages of wheeled robot and two-legged robot.

    Automatic Sorting of Skittles or M&Ms by Colour

    Do you sort M&Ms or Skittles by colour before eating them?  For example, eat all the yellow ones first, then the red ones, then the blue and so on. Brian Egenriether, an electrical engineer, decided to make a small machine that looked like an appliance, which could perform these tasks automatically. This mechatronics project took him about 5 weekends to make. The use of the machine is very simple: pour Skittles or M&Ms into it, push a button and have candies sorted. Let us look at the construction.

    Mechatronics System as the Future of Cooking at Home

    Do you get up in the morning and don't feel like making breakfast? One of the solutions is food delivery service, which leaves your takeout order outside of your front door. Other solution is a private chef who is responsible for shopping for food, menu planning, preparing and cooking meals for you. But if you love mechatronics systems, your solution is a mechatronic kitchen. It allows you to save time, free up your day from routine cooking, plan and adapt your menu according to different diets and lifestyles.

    Three Wheels Balancing Robot

    The three wheels balancing robot is similar to a ballbot from the point of view of the goal. In comparison to ballbot which balance itself on a single ball, three wheels balancing robot is designed to balance itself on a single rod. The common characteristics of this kind of robots is that there’s one sole contact point to the ground.

    Stretch - Boston Dynamics Unveils New Robot for Warehouse Automation

    Boston Dynamics is the global leader in mobile robotics. Their popular robots are SpotMini, Spot, Atlas and Handle. Now they has revealed 'Stretch', which is a new box-moving robot designed to support the growing demand for flexible automation solutions in the logistics industry. A Massachusetts company well known for its humanoid robots and dog-like androids is preparing to muscle its way into the warehouse automation industry with its latest mechatronic solution. Warehouse automation is a fast-growing market fueled by increased demand in e-commerce. The robot called Stretch is Boston Dynamics’ first commercial robot specifically designed for warehouse facilities and distribution centers. Robert Playter, CEO of Boston Dynamics said: Warehouses are struggling to meet rapidly increasing demand as the world relies more on just-in-time delivery of goods. Mobile robots enable the flexible movement of materials and improve working conditions for employees. Stretch

    Ballbot - Ball Balance Robot

    A Ballbot (botball) is a mobile robot designed to balance itself on a single ball, both while in motion or staying in a place. We can say, that it is a "single wheel vehicle". The main characteristics of this kind of robots is that there’s one sole contact point to the ground. This means that the robot is inherently unstable. It’s like when you try to stand on a ball.

    High Speed Book Flipping and Scanning

    We are increasingly accustomed to using e-books and each book is now released in a digital version too. Progressive digitization of the world around us causes the demand for devices to enable the digitization of paper books, official documents, and notes. However, the conventional technology can not meet the demands for ease-of-use and high-speed book digitization. Ishikawa Oku Laboratory at the University of Tokyo works on a solution.