The engineer who invented the Mars rover suspension in his garage [video] | Hacker News Reader

The engineer who invented the Mars rover suspension in his garage [video]

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388 pointsUltraSane56 comments

I had the privilege of working with Don back at JPL at the time he invented the rocker bogey. (I wrote the software for the first prototype with a computer on board.) Not only was he brilliant, he was also a really nice guy. I didn't appreciate at the time how rare that combination of traits is among humans.

To my astonishment, it turns out Don doesn't have a Wikipedia page (though the rocker bogie suspension does).

He really deserves a page, in the engineering world this is as notable as it gets. The number of skills casually on display here. Just wow.

https://en.wikipedia.org/wiki/Rocker-bogie

AI-assisted project idea: recreate that animation as code, and then include the differential gear.

Edit: Someone already made a 3D animation: https://m.youtube.com/watch?v=hO8DbfE7hJw

Reminds me of the fractal vise - https://www.youtube.com/watch?v=QBeOgGt_oWU

Thanks for pointing out the rocker-bogie Wikipedia page. There's a true dearth of info about them. Do you happen to know if there's any kinematic analyses of these suspensions available? I used to do stress analysis in the aerospace industry and I've been interested in that sort of analysis since the 1997 Sojourner rover.

I'm not sure what you mean by kinematic analysis, but the video mentions several analytical analyses of his suspension and how he came up with it. They did some computer simulations to optimize how it would deal with various obstacles. Really cool and clever.

I wasn't sure what word to use. That suspension has lots of pin joints and linkages, which are usually the subject of kinematics, 3-bar linkages, mechanisms, etc etc.

I realize that the stiffness of the rockers and links will make a difference in how forces are distributed, because that suspension is clearly not statically determinant, but the main factor in the design has to be the proportions of the links and beams. I can't find anything about that, so I asked.

> I realize that the stiffness of the rockers and links will make a difference in how forces are distributed, because that suspension is clearly not statically determinant

I think it's (mostly) the terrain geometry (plus gravity) that constrains the system, not joint or bar stiffness. This makes them feasible to analyze with the tools of theory of mechanisms I believe.

Also a really noteworthy insight I think he had was that when there is some kind of non-planar geometry arrangement of the wheels, that tends to create additional (perpendicular to surface) force on the wheels, effectively increasing the coefficient of friction. Think how a child may be able to climb a door frame by pressing hard enough on the sides.

> Do you happen to know if there's any kinematic analyses of these suspensions available?

Sorry, I have no idea. I never actually worked on the mechanics, just the software.

"Don is clearly one of those one-of-a-kind engineers JPL has thrived upon for all its history." -- Mike Sander, 02 JUN 2002

It's hard to think of more meaningful praise for Donald Bickler.

This guy has incredible videos on hiking gear, examining common claims scientifically and rationally. He never gave any hints as to his professional background, so as not to taint his arguments with appeals to authority. It makes perfect sense that he grew up in this environment, doing engineering work for NASA as a kid!

I know this guy from his videos over the years on hiking topics, like how to safely purify water with the minimum fuel and how to pack calorie efficient food.

His videos are incredibly well researched, very in-depth, and absolutely zero fluff. Very much feels like his cycle is to get intrigued by a topic, spend a year deep diving into everything that's published, extrapolate what he can from there, then summarize it in a 1 hr video.

This is really Youtube at its best.

Deep dive into a niche topic, expert led, compelling storytelling, and professional production.

Not sure how/if something this could have been created / shared 20+ years ago.

If you are an engineer and you haven't watched this video please do yourself a favor and do so. I watch very little TV or YouTube, but I ended up taking off the afternoon after this video unexpectedly drew me in. It was impossible to not finish it - so if you do start watching it make sure you have two hours to spare. This is easily the best and most enjoyable thing that I've watched in the last several years!

I bumped this video to the top of my watchlist because of your comment, thanks for that. My takeaway is that the rocker-bogie is one of the best examples of an elegant passive solution I've ever seen.

This kind of mechanism is fascinating. I built a four-wheeled version and even that is beautifully smooth when one wheel goes over a bump because the chasis maintains an average orientation based on the positions of all the wheels. The video shows an 8-wheeled one but it still only has two rows of wheels. I've wondered how to generalize it to an arbitrarily sized grid of wheels so a vehicle would be like a flexible mat that conforms to the ground. I couldn't work that out but I'm no Don Bickler. FEA software has a feature called "RBE3" which models an even more general case of any number of "wheels" and they can also move in any direction while still keeping the orientation of the "chassis" (dependent node) rigidly determined by their average displacements. The "R" stands for rigid because every part is rigid or completely free - no springs! There seems to be nothing like it in machines or nature but it's a beuatifully elegent and seemingly natural mechanism - if it was possible to build.

Most of my comments on hacker news are to point out something incorrect or mischaracterized. All I can come up with here is that this is a brilliant and heartfelt and entertaining documentary. Thanks to OP for posting.

Best not read the comments until you've watched at least the first four minutes of the video.

Seconded, and maybe worth expanding why: there’s a very heartening reveal within the first few minutes that would be spoiled by reading the comments (which, surprisingly for YouTube, are all very positive about it.)

The video's narrator is the son of the engineer who invented the suspension.

It is even listed in the video description. What's this idea that this is a spoiler or integral to the video?

Apparently the first Mars Rover operated on only 5 watts of power. A common bathroom nightlight draws ~7 watts.

> A common bathroom nightlight draws ~7 watts.

Philips "60W" equivalent (806 lm) LED lamps are 3.8 watts.

Yes, they're referring to incandescent nightlights, which were admittedly more relevant back when these rovers were designed than they are now.

I don't think that was the point being made by GearSkeptic, the video creator. It was a demonstration to the lay person who may not be familiar with what 5W "looked like".

The rocker-bogie suspension is fascinating because it solves a real constraint problem with elegance rather than brute force—reminds me of how the best engineering often comes from working within limitations. As someone who's debugged systems under resource constraints, I'm curious whether the garage iteration process actually made it into the final Mars rover design, or if it had to be significantly redesigned for the extreme thermal/radiation environment.

>reminds me of how the best engineering often comes from working within limitations

Engineering, in a nutshell, is all about building things under (physical and social/economic) constraints.

Is this the same guy who developed the Spyderench?

https://spy-derco.com/catalog/details/T01/SpydeRench-trade-/...

https://multitool.org/blog/spyderco-usa-spyderench

I don't think so (either by the vibe/tone of the guy portrayed in the video or from my searches.)

I love how you can just fell the admiration he had for his dad.

Not surprised of such article.

It's not the first time something important is built in a garage:

for example, the Apollo 11 lander; a lot of people were thinking it was made from aluminum folio and cardboard in a garage, but actually it was kapton folio and professional-grade cardboard.

Is it true that a walking system only to operate its legs and limbs would still consume more power than a rocker bogie — with all the innovations in battery tech?

Ofc Yes.

On Mars would any other mobility system today achieve better performance for it's purportedly stated(neigh most ridiculous stated but to be fair difficult engineering) goals i.e. colonization? Also no.

I am surprised after watching this that there is so much of the Boston dynamic stuff man/dog walking out there, given that mobility is so well accomplished. Do you need — to invest — an anthropomorphized man to scale walls and be stable after getting kicked around?? I know one thing here on earth all large scale semi(think agro machines) and almost fully(delivery bots) autonomous look nothing like anthropomorphics or canines.

Maybe I have the dunning Kruger effect, because I am not a robotics engineer, but why is building an anthropomorphic _mobility_ platform so important to solve _pragmatic_ problems?

I'm also wondering why people are so enamored with these humanoid robot - what they've accomplished is impressive, but from the perspective of replacing humans, I'm sure we are many years away from the versatility required to replace skilled tradespeople.

A humanoid robot shambling along a factory floor to pick up a plastic cover and deposit it onto a shelf does not look like a trillion dollar industry. I'm sure there are much more straightforward ways of accomplishing the same stuff.

Imo the biggest advantage of reproducing humanoid forms, is that then the robot can be teleoperated with full body harnesses that track the human operator. One such system I like really much, is what the Japanese use for fixing overhead power wires - it looks like a humanoid robot torso mated to a mobile crane.

Altough the technology behind that could be done in the 80s, with electromechanical analog controls.

Isaac Asimov answered that - the world is already built for humans so if robots are going to be generally useful replacing and operating alongside humans, they'll have to be human-shaped.

It’s a benchmark that people can understand. And of course humans evolved along with our environments. There are many places where a wheeled contraption can’t go without clearing a path for itself.

Likewise for intelligence. Is human-style intelligence the best benchmark for intelligent machines?

Most factories, including the one I work in, are already designed for wheeled robots, in a sense, because anything heavier than a certain amount is moved around on wheeled carts.

Legged robots can be more efficient, in theory.

Whenever you drive/walk in soft terrain, the wheel/leg is constantly climbing the ramp created by it sinking into the terrain. In a perfect system, this determines how much power you need to move. This is why trains are so efficient. A hard wheel on a hard rail has very little deflection -- so excellent efficiency.

Wheels have to climb that ramp for every inch of travel. Legs get to step forward and only take that penalty for each step. If everything else is the same, the legs win on soft terrain.

But everything else is never the same :-). The early legged vehicles used linear motions, which means you have these very long sliding surfaces. This is heavy and the drive system efficiency dominates over the terrain interaction efficiency. Add in the fact that you have multiple axis to drive and the weight and drive losses really add up.

Modern dog and human style walking robots are MUCH better on efficiency than those early designs. However, they require enough sensing and compute to dynamically balance. Legs can do things that wheels can't, but you have to have smart enough software to take advantage of that. The compute available for a high radiation environment is a fraction of what is in your smartwatch. Wheels are still winning on energy efficiency, but at least it's getting closer.

I worked on Dante at CMU and Marsokhod at NASA Ames; and was in the same group that developed Ambler.

I’d say a lack of imagination.

Lose mobility for a few weeks or months, like breaking both legs (or just try wheelchair access) and see how much of even the paved first world is inaccessible.

Nevermind less refined places like well-maintained hiking trails.

And you can forget about actual trail-blazing.

Then appreciate just how flexible and robust animal and human mobility really is!

The usual reasoning is that 2 legged robots will be able to use the same affordances that two legges humans do.

Legs look cooler, and so get the investment dollars.

There isn't enough money atm to be gained by solving realistic problems, so Tesla et al have to convince investors that it's going to be an incredible leap forward. Which means impressing investors, not focusing on solving problems.

Building a robot and building a robot to operate on Mars are eye-wateringly different challenges.

a bicycle is more efficient than walking, it's not hard to see why - moving a mass up and down is wasted energy

> why is building an anthropomorphic _mobility_ platform so important to solve _pragmatic_ problems

because something rolling along isn't as visually impressive as a complex system to walk, and these companies require hype

To answer my own last question I would also think probably not that important.

What an incredible mind. I wonder how many more people out there there are that have made huge contributions to humanity and very few know their name.

I worked with Lee Sword (also RIP) for a while; he was on the mechanical team for Sojourner. Interesting guy.

"There are no shortcuts to expertise".

What a fantastic post this.

As Marx put it: "there is no royal road to science, and only those who do not dread the fatiguing climb of its steep paths have a chance of gaining its luminous summits.

Wow, this turned out to be an amazing documentary!

Wish there was a bottled scent that captured the smell of that still shot of his garage/shop! Inspiration by Bickler.

I loved seeing a IIci riding on the prototype suspension.

Cool!

I just popped in to add that NASA employee Charles White, a scientist involved with the Mars Rover project, also helped make a Burning Man Mars Rover Car (back before Playa Burning Man was completely and utterly torched twice over by Military Industrial Complex Vacationers and Billionaires) and you can hear an interview with him here on Charles White's yt channel: https://youtu.be/BKGROOedAgI ( Mars Rover Art Car interview with Ray Cirino and Charles White )

Charles White is a pretty good guy in my opinion, we play the same video game (EvE: Online) Where Charles White is a very, very well known community member who is known as "The Space Pope". He officiates weddings at our Iceland Fanfest gathering and also runs a Suicide Prevention Outreach group in EvE: Online, as well as teaching leadership skills.

Here's Charles White giving a presentation as an Official NASA employee about Space and our solar system at EvE Fanfest 2016: https://www.youtube.com/watch?v=Atm6Y_JYPEU

Heres a interview about EvE: Online with the Space Pope: https://www.youtube.com/watch?v=dWuj7LfyN4U

anyhow sorry to hijack this about EvE: Online but we have lots of cool people like Scott Manley playing, too: https://www.youtube.com/watch?v=huZlA0eg12U

I might be utterly ignorant about the happenings in the world around me, but it seems there's less of this funky experimentation and pushing boundaries not directly tied to hitting some economically valuable goal nowadays.

Dad for scale

I love this part at 25 minutes:

"There was a formula in Becker's book for a four-wheel drive vehicle with a powered trailer. Well, Don said, "I played with a formula and quickly found that the most sensitive dimension is the length of the rear axle to trailer hitchball. As I reduced it, performance increased. I went to less [negative number] and the performance continued to increase. But how can you have a negative length for this connecting member?

Don realized that a negative connection length just meant moving the pivot beyond the traditional attachment point. Instead of connecting everything to the frame, he made the four-wheel set a bogie in and of itself and attached it to another member with the other set of wheels. Another way to think about it is that the whole thing is a bogie with a rocker at one end, which is how Donna Shirley christened it when she saw the new design. Hence, the rocker bogie was born. And Don Bickler became known as The "Bogie Man" around JPL."

----------

I also like the email reproduced at 1:37:06 for the picture it gives of Don as a mentor:

"Mark,

In response to Don Bickler’s efforts over the last 2 months or so, I can't help but tell you how much I want to hang out with this guy! He is my hero! Every time we talk, I feel I walk away with some extra piece of knowledge that I didn’t have before. I told Don, it is so unfortunate that engineers these days are nothing like they were when he came out of school. He has so much common sense and has such a great ability to simplify the situation and come up with a solution that will not only work, but be simple and easy to build, while at the same time wanting nothing more than to solve the problem at hand, he thrives [at] it and that is something I really enjoy observing!

I'm sure this does not come as a surprise to you as every one I talk to, when I tell them that Don Bickler is helping us resolve this spring issue, tells me the guy is a legend and to soak up everything you can from him! Simply put, Don has been an asset to this issue we have had, he has quickly come up with a resolution so we can move forward with the spring design we have.

The issue is not yet resolved because we still have to design and build the spacers that Don recommends, but based on some preliminary testing, it looks like Don's resolution will be the remedy we are looking for. If possible, I would like to be locked in a room with Don through any type of project. Please let me know when and where.

I am currently working in Madrid right now until the 28" but if you'd like more info, please feel free to contact me on my cell phone.

Thanks in advance,

Jason Carlton

Jet Propulsion Laboratory" [line breaks added to ease reading]

Interesting documentary! I'd like too kick Tony Spear in the nuts afterwards though. What a shitbag.

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