"Straight out of science fiction" Looks a lot like Westworld, and the series doesn't end well for humans.
It's like they watched Westworld and didn't get the message. Like, at all.
Protoclone: Bipedal, musculoskeletal Android
41–50 of 54 posts
Re: Protoclone: Bipedal, musculoskeletal Android
#42Their video: https://www.youtube.com/watch?v=H7dhwFcuUn0 Taken at face value, it is a very cool project. With pneumatic muscles, the biggest challenge is actually not strength but control. Fine strength/distance control is difficult. Pneumatic muscles are more for bang-bang control (on/off). The company seems to address this issue by having many "myofibers" and recruiting the fibers one by one. However, in the video,…
Indeed, the valve/line/pump mass will greatly dominate design cost. The reason no one uses pneumatic actuators for repeatable positioning systems is gas is compressible, adiabatic thermal problems, and dangers when something fails. Never saw automatons as particularly practical either, as the motion control planner balloons in complexity. Makes creepy looking sculptures though... =3
>repeatable positioning systems
Typical in CNC, but is it really useful in closed-loop systems that use computer vision to adjust to an uncontrolled environment ? I've been wondering if I could reproduce something like mobile aloha but with sg90 servos instead of expansive dynamixel servos (in this case, I'm not looking at applications that require torque obviously).
Re: Protoclone: Bipedal, musculoskeletal Android
#43Earlier quoted context omitted.
Indeed, the valve/line/pump mass will greatly dominate design cost. The reason no one uses pneumatic actuators for repeatable positioning systems is gas is compressible, adiabatic thermal problems, and dangers when something fails. Never saw automatons as particularly practical either, as the motion control planner balloons in complexity. Makes creepy looking sculptures though... =3
>repeatable positioning systems Typical in CNC, but is it really useful in closed-loop systems that use computer vision to adjust to an uncontrolled environment ? I've been wondering if I could reproduce something like mobile aloha but with sg90 servos instead of expansive dynamixel servos (in this case, I'm not looking at applications that require torque obviously).
Your intuition is quite correct that closed-loop means open-loop repeatability is not critical, but controlability (non-stickness, smallest possible controlled movement) still matters. Motors are well behaved and continuous, so even with some backlashes, you will be fine. There are also ways to compensate for backlashes from software (e.g. same approach angle for end effector).
Aloha is a fascinating project and would love to hear more about what you are thinking. Dynamixel indeed is too expensive
Re: Protoclone: Bipedal, musculoskeletal Android
#44Earlier quoted context omitted.
Indeed, the valve/line/pump mass will greatly dominate design cost. The reason no one uses pneumatic actuators for repeatable positioning systems is gas is compressible, adiabatic thermal problems, and dangers when something fails. Never saw automatons as particularly practical either, as the motion control planner balloons in complexity. Makes creepy looking sculptures though... =3
>repeatable positioning systems Typical in CNC, but is it really useful in closed-loop systems that use computer vision to adjust to an uncontrolled environment ? I've been wondering if I could reproduce something like mobile aloha but with sg90 servos instead of expansive dynamixel servos (in this case, I'm not looking at applications that require torque obviously).
In general, remote operated equipment still suffers latency, and thus visual servoing doesn't work well even in ideal controlled lighting conditions.
One of the lowest-cost commercial UR5 options with force-feedback is usually packaged with a traditional turtle-bot research platform. These are safer to use around people without a cage, as you can set impact safety thresholds:
https://www.universal-robots.com/products/ur5e/
https://github.com/UniversalRobots/Universal_Robots_ROS_Driv...
The hardware is a solved problem, and there are 3D printed 5-axis and 7-axis community kits around too.
Have fun =3
Re: Protoclone: Bipedal, musculoskeletal Android
#45Earlier quoted context omitted.
>repeatable positioning systems Typical in CNC, but is it really useful in closed-loop systems that use computer vision to adjust to an uncontrolled environment ? I've been wondering if I could reproduce something like mobile aloha but with sg90 servos instead of expansive dynamixel servos (in this case, I'm not looking at applications that require torque obviously).
Your intuition is quite correct that closed-loop means open-loop repeatability is not critical, but controlability (non-stickness, smallest possible controlled movement) still matters. Motors are well behaved and continuous, so even with some backlashes, you will be fine. There are also ways to compensate for backlashes from software (e.g. same approach angle for end effector). Aloha is a fascinating project and woul…
"closed-loop means open-loop repeatability is not critical"
Hobby servos have limited repeatability especially as they wear, and when swinging an arm with shifting center of mass the errors will be quite obvious.
One may want to look at the UR5 platform design before wasting time and money. Best of luck =3
Re: Protoclone: Bipedal, musculoskeletal Android
#46Earlier quoted context omitted.
Your intuition is quite correct that closed-loop means open-loop repeatability is not critical, but controlability (non-stickness, smallest possible controlled movement) still matters. Motors are well behaved and continuous, so even with some backlashes, you will be fine. There are also ways to compensate for backlashes from software (e.g. same approach angle for end effector). Aloha is a fascinating project and woul…
"closed-loop means open-loop repeatability is not critical" Hobby servos have limited repeatability especially as they wear, and when swinging an arm with shifting center of mass the errors will be quite obvious. One may want to look at the UR5 platform design before wasting time and money. Best of luck =3
> Hobby servos have limited repeatability especially as they wear, and when swinging an arm with shifting center of mass the errors will be quite obvious.
Your statement is correct by itself, but it is not completely applicable to what the GP comment (not my comment) said. Aloha uses optical encoders (which themselves are far better than hobby-grade potentiometer servo encoders) and in fact also compensates for inaccuracies in the optical encoder.
I have no experience with UR5 but looks interesting. Any reason why you recommend this?
Re: Protoclone: Bipedal, musculoskeletal Android
#47Earlier quoted context omitted.
"closed-loop means open-loop repeatability is not critical" Hobby servos have limited repeatability especially as they wear, and when swinging an arm with shifting center of mass the errors will be quite obvious. One may want to look at the UR5 platform design before wasting time and money. Best of luck =3
> Hobby servos have limited repeatability especially as they wear, and when swinging an arm with shifting center of mass the errors will be quite obvious. Your statement is correct by itself, but it is not completely applicable to what the GP comment (not my comment) said. Aloha uses optical encoders (which themselves are far better than hobby-grade potentiometer servo encoders) and in fact also compensates for inacc…
"Any reason why you recommend this?"
Pre-built 3D simulation models for easier software development, official ROS support from the company, and better physical safety with advanced force-sensing motion systems.
"optical encoders" have their own set of issues... usually require quadrature encoder tracking FPGA or dedicated ASIC features in the mcu. i.e. you now have 2 problems to solve, and higher costs.
Best of luck, =3
Re: Protoclone: Bipedal, musculoskeletal Android
#48Earlier quoted context omitted.
>repeatable positioning systems Typical in CNC, but is it really useful in closed-loop systems that use computer vision to adjust to an uncontrolled environment ? I've been wondering if I could reproduce something like mobile aloha but with sg90 servos instead of expansive dynamixel servos (in this case, I'm not looking at applications that require torque obviously).
Your intuition is quite correct that closed-loop means open-loop repeatability is not critical, but controlability (non-stickness, smallest possible controlled movement) still matters. Motors are well behaved and continuous, so even with some backlashes, you will be fine. There are also ways to compensate for backlashes from software (e.g. same approach angle for end effector). Aloha is a fascinating project and woul…
First I'd like to reproduce the Push-T task of the policy diffusion paper (video here: https://diffusion-policy.cs.columbia.edu/)
Afterwards I'd like to tackle useful tasks related to gardening/botanical experiments: uprooting weeds, handling pests, harvesting small fruits. What's interesting is that you can develop new approaches to these problems. Uprooting stuff is difficult to do for a machine I guess. Maybe just cut the weeds with scissors every day, that'll teach them a lesson. Or remove aphids "by hand".
Another interesting thing is to do more scientific tasks such as handling a lot of tedious tasks on many, many plants. Example: creating polyploid plants is a lot of manual labor, what I'm talking about here is basically lab automation (doing flow cytometry on dozen or even hundred of samples).
Another aspect to explore in this space is continuous measurements (measuring photosynthesis efficiency for instance). I'm not a botanist but it seems that measuring devices either come in the form of a box you put the plant in, and you can get quasi-continuous measurements, or they are hand-held and you can only do punctual measurements (typical example: chlorophyll fluorometry). Also plants grow and change shape so putting a measuring device on a plant is in fact rather difficult. I think something like Aloha (even without the "Mobile" extension) could help tackle these situations.
Re: Protoclone: Bipedal, musculoskeletal Android
#49Earlier quoted context omitted.
> Hobby servos have limited repeatability especially as they wear, and when swinging an arm with shifting center of mass the errors will be quite obvious. Your statement is correct by itself, but it is not completely applicable to what the GP comment (not my comment) said. Aloha uses optical encoders (which themselves are far better than hobby-grade potentiometer servo encoders) and in fact also compensates for inacc…
"Any reason why you recommend this?" Pre-built 3D simulation models for easier software development, official ROS support from the company, and better physical safety with advanced force-sensing motion systems. "optical encoders" have their own set of issues... usually require quadrature encoder tracking FPGA or dedicated ASIC features in the mcu. i.e. you now have 2 problems to solve, and higher costs. Best of luck,…
Related optical encoder project I found a while back that used to rely on an FPGA but doesn't anymore:
Re: Protoclone: Bipedal, musculoskeletal Android
#50Earlier quoted context omitted.
>repeatable positioning systems Typical in CNC, but is it really useful in closed-loop systems that use computer vision to adjust to an uncontrolled environment ? I've been wondering if I could reproduce something like mobile aloha but with sg90 servos instead of expansive dynamixel servos (in this case, I'm not looking at applications that require torque obviously).
In general, remote operated equipment still suffers latency, and thus visual servoing doesn't work well even in ideal controlled lighting conditions. One of the lowest-cost commercial UR5 options with force-feedback is usually packaged with a traditional turtle-bot research platform. These are safer to use around people without a cage, as you can set impact safety thresholds: https://www.universal-robots.com/products…
It's between 20k and 30k dollars. Maybe your profession is suffering from "industrial bias": it focuses only on high-end robotics because it's the only thing that makes sense economically for now and anything super-cheap is seen as laughable ? Wasn't it the case for FDM 3D printer too before they went mainstream in the 2010s ?
I just want to build a toy and explore what's possible with this technology for non-serious applications. The servos may wear too quickly ? I'm fine with that. However I have trouble figuring out how cheap I can go. If I can carry out a task using the "control arm" and the "working arm" performs ok, does that mean Aloha will be able to learn it ? What are the limits then ? What if my arms are really flexible (as flexible as a 10 cm section of a PLA filament for instance), but I manage to carry out the task, can something based on policy diffusion learn to handle the task with "bones" that flex and oscillate ?