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Comment by viach | Hacker News Reader

Genuine question - why 2 wheels, not good old 4? Only because these robobees look cooler this way?

Probably because it's Boston Dynamics, not Boston Practical Industrial Robots.

My guess is that [1] 4 wheels don't solve the fundamental problem of lifting - counterweights (unless your 4-wheel "platform" is so wide to not easily fit / maneuvre in the warehouse), and [2] 2 weels are enough - with modern motors, microcontrolers and feedback algorithms, 2-wheel platforms (think Segway) are perfectly stable.

Forklifts pretty much solved this. Just put the weight in the back.

I don't think Segways are exactly a great argument for practical design.

From https://www.bostondynamics.com/handle :

Handle is a robot that combines the rough-terrain capability of legs with the efficiency of wheels. It uses many of the same principles for dynamics, balance, and mobile manipulation found in the quadruped and biped robots we build, but with only 10 actuated joints, it is significantly less complex. Wheels are fast and efficient on flat surfaces while legs can go almost anywhere: by combining wheels and legs, Handle has the best of both worlds.

Handle can pick up heavy loads while occupying a small footprint, allowing it to maneuver in tight spaces. All of Handle’s joints are coordinated to deliver high-performance mobile manipulation.

I'm no robotics engineer, but to me the design looks brilliant. I suspect that the biggest problem with a machine that needs to pick up and carry objects in a somewhat humanoid fashion is going to be weight and balance. They've attacked the problem by making the entire body of the robot a seesaw and adjustable counterweight to control the balance. Having the robot on two wheels also gives the robot a smaller footprint, gives it a zero turn radius, simplifies how you control turning, and probably also simplifies the navigation control algorithms.

Way easier to change center of gravity.

You are imagining a robot by looking at the application demonstrated in the video. Boston Dynamics is not building robots that can just move boxes. This is just a predecessor to something bigger that can do different things, almost like a human.

I had the same question. The robot looks too complicated for what it's doing.

That's exactly what surprises me about BD. It's not like they made one complicated robot. They have an entire lineup of them! These robots are so highly advanced they make conventional robots look like they came from the stone age. However that complexity probably comes at a hefty price tag which makes it lose against simpler robotics.

I never saw BD as a product company.

> We began as a spin-off from the Massachusetts Institute of Technology, where we developed the first robots that ran and maneuvered like animals. Now we are taking the next step, combining the principles of dynamic control and balance with sophisticated mechanical designs, cutting-edge electronics, and software for perception, navigation, and intelligence.

They seem pretty clearly to be a R&D company around dynamic control and balance, so it makes sense that they would have rather complicate robots.

I love making things. I dabble at designing them. I hate companies that are all about the numbers with a fury (people are not numbers).

But once in a while I see a company run by engineers, and I just shake my head and back away. BD seems like a "tech utopia", with all the bad connotations that can have.

Is it more energy efficient to use a counterbalance? Compared to simply putting the load onto motor torques?

I understand energy efficiency is an odd thing to optimize for at this stage, but that would explain the design.

apes might have had the same question when they first saw humans :)

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