MIT’s Innovative Mini Arm Puts Expert Digging Skills in Anyone’s Hands on Day One

Years of practice used to separate someone who could dig a clean trench from someone who left a messy hole. Excavator operators spend months, sometimes years, learning how two joysticks map to the boom, stick, bucket, and cab. Every small wrist movement has to translate into a precise action out in the dirt, and that mental translation does not come easily. Demand for skilled operators keeps climbing, with tens of thousands of openings appearing every year, yet the training bottleneck remains stubborn.

MIT engineers decided that simply throwing more practice time at the problem with the same controls was not the solution. Instead, they created another type of controller, one that resembles and feels like a little, miniature excavator. They name it the World-Space Interface. It’s a mechanical arm and bucket that you just grab and move as if you were picking up something with your own arm: extend, twist, and close your fist. It’s all extremely intuitive. Behind the operator, a six-screen display depicts a full-size virtual excavator performing the same task as if it were on a real site, such as a roadway, a riverbank, a mining hole, or anywhere else.

Hermano Krebs, the project manager from MIT’s Mechanical Engineering department, puts it succinctly. Normally, operators must create a mental map of how all of the machine’s components work together before they can use it; however, with this interface, users simply mimic the action of grasping a rock or digging into dirt, and the computer handles the rest. The name ‘world-space’ is a useful indication because it refers to anything outside the cab. The old method, which used joysticks, was similar to trying to do a mental trick by coordinating all of the different parts of the machine independently, but the new method accomplishes it all for you.

Sumitomo Heavy Industries in Japan has boosted the project, in part because they have an aging staff and need to get new operators up to speed as soon as feasible. Over several years, they perfected the mechanical arm and software that allows the virtual excavator to perform the same motions as the real one, resulting in a training platform that can be used in real life as well as in the classroom.

They put some volunteers to the test: one hour per day for seven days in fifteen different locations, scooping sand and gravel, digging trenches, clearing debris, removing branches, breaking boulders, and so on. Some used ordinary joystick simulators, while others used the small arm, and the results were rather impressive. With the joysticks, even the experts couldn’t meet the pros’ standards, but with the small arm, the newcomers matched the pros from the first session.

One of the team members, Joao Buzzatto (an MIT postdoc and co-author), believes this is the first interface that does not require a joystick. The small arm does all the work, and as you move it, the virtual machine follows suit. The notion is that you already know how your own arm works; this simply allows you to apply that knowledge to the digger. Krebs envisions this expanding beyond training rooms, with the small arm sitting alongside an operator in the cab, almost like an exoskeleton that you slide your arm into. Or, even better, it may allow you to sit comfortably in a trailer back at headquarters and control the device remotely, which is great for hazardous or difficult-to-reach circumstances. The next step may be force feedback, which allows you to feel the weight of a boulder or the resistance of packed ground, which is not currently available.
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