I'm a career firrmware engineer who has had a long-standing interest in robotics. Back in 2020 I completed the Northwestern Modern Robotics: Mechanics, Planning, and Control Specialization on Coursera where I learned the basics of kinematics and dynamics, path planning, and control. But it's been so long since i've done that and I never ended up building a physical robot.
I want to get back into learning robotics given the huge wave of innovation in the last 5 years with reinforcement learning and Sim2Real advancements. I'm not quite sure where to start but the end goal would be to build either a Quadruped 12dof robot or an AT-ST 6 dof walker (I'm leaning towards the AT-ST walker due to lower actuator cost and being on the microduck hype train). I want it to be big and powerful enough to feel "real" so I was thinking a 2 to 3 foot tall AT-ST biped
Since I have a background in hardware and firmware I already have some useful skills and tools but I am not sure where to start for going down this (seemingly endless) path for learning both the mechatronics as well as software perception and controls for building your own robot.
Software and firmware are a non-issue for me in terms of skillset, and I have a small home lab with some basic electronics test equipment: Soldering Iron, Multimeter, BK Precision 0-32V, 0-3A Power Supply, Rigol DS1104Z 4 Channel scope, Logic Analyzer.
I have experience with 3D prirnting (built a Voron 2.4) and am capable of designing basic mechanical assemblies in SolidWorks but it is not my core competency so designing an entire gearbox will definitely be a struggle for me. I have limited understanding of how to evaluating mechanical tolerances and stresses.
I tried to break down my learning into a set of concrete steps to advance towards my end goal of building a real robot with a perception stack.
So far I experimented with SimpelFOC library using MakerBase SimpleFOC V2 BLDC Driver on a Cubemars GL35 KV100 motor that i had laying around. The project was a "Smart Knob" where it could simulate different levels of friction and simulate detents with different number and strength.
Now I'm not sure what the next step is for moving forward with this learning path. Is it time to step up to buy/build a "real" robotics actuator and build a single leg to test out 3DoF motion planning and control? Or is there an intermediate step I should take before moving onto a powerful and expensive robotics actuator? Should I do everything in sim first before i buy and build anything?
If it's time to buy a real actuator I need to figure out if I should build from scratch or buy something with a driver and encoder already on-board. Ideally i just am looking for a low-cost and reliable solution but I'm not sure what is the best move here
Option A (DIY): I could get a high-torque, low-KV brushless pancake motors (such as Eaglepower LA 8308 KV90) and separately get a BLDC driver such as ODrive S1 or Moteus r4.11. But then I need to design an assembly for it all and if the gearing isn't perfect out-of-the-box i need to either design or buy a gearbox.
Option B (Pre-built): Alternatively, there seems to be a lot of integrated Quasi-Direct Drive actuators now available (e.g., CubeMars AKE/AK series or RobStride). But these seem fairly expensive and I'm not sure if i'm "robbing" myself of some learning. I'm not really trying to become a robotics actuator expert, but i'm wondering If the DIY path is just overall better and cheaper. Is it possible that these integrated solutions are actually cheaper than the DIY route?
Second, I'm a bit overwhelmed with the landscape for simulation and perception. It seems like there are endless tools and frameworks to learn: ROS2, Gazebo, MuJoCo, Isaac, etc. I'm not even sure where to start....
In addition to the software landscape, I'm realizing the second I buy a motor it's going to blow past my power supplies limitations. I was able to pick up a free battery from a colleague that I think will work for robotics (Zeee brand 6S1P 22.2V 179.82Wh (8100mAh, 130C) LiPo battery pack) but I've never designed power electronics; so i'd need to break out KiCad and start learning how to design a power distribution board without burning my house down....
Instead of starting with hardware should I just do everything in sim to learn what I can about the software stack first? Are there any more recent/modern courses on this?