LeggedAI Weekly Meeting
Kunzhao Ren
rkzdtc@gmail.com | +1 608 590 6494
Madison, WI
Legged Robots | MPC | RL | WBC | RWM
Overview
- Rigid Ground
- Go2 Hop
- Go2 Sideflip
- Go2 Jump on Table
- Built-in Deformable Utilities in Simulator
Go2 Hop on Rigid Ground
HW - My_unitree_go2_gym
Training - mjlab
Go2 Sideflip on Rigid Ground
TO - se3_trajopt
Training - mjlab
Deploy - mujoco
Go2 Jump on Table
DIAL-MPC
TO - se3_trajopt
Physics Simulation Stack: Core Concepts and Roles
| Name | Category | Role |
|---|---|---|
| Warp | Compute framework | GPU-oriented Python framework for writing simulation and geometry kernels |
| JAX | Compute framework | Array computing and autodiff framework for accelerated numerical computation |
| MuJoCo | Physics engine | General-purpose robot dynamics and contact simulator |
| PhysX | Physics engine | NVIDIA physics engine used for real-time and GPU-accelerated simulation |
| Newton | Physics engine | New robot-focused physics engine built on Warp |
| MJX | Acceleration interface | MuJoCo acceleration API/front-end for batch and accelerator-based simulation |
| MJWarp | Engine implementation | Warp-based GPU implementation of MuJoCo-style simulation |
| Isaac Gym | Simulation application | RL-oriented GPU simulation environment |
| Isaac Sim | Simulation platform | Full robotics simulation platform with scenes, sensors, and multiple backends |
Deformable Object Support in Off-the-Shelf Simulators
| Name | Mechanism | Training Framework |
|---|---|---|
| MuJoCo | Point-Mass Network, Flexible Edges, Collidable Surface | |
| MJWarp | Point-Mass Network, Flexible Edges | mjlab |
| Newton | Point-Mass Network, Flexible Edges | Isaac Lab |
| Isaac Sim | FEM-based, collision mesh, simulation mesh | Isaac Lab |
Legged Robot Hopping and Flipping on a Trampoline
Task1: Use Isaac Lab’s built-in deformable object functionality to model a trampoline.
- Integrate trampoline into training with domain randomization over
youngs_modulusandtrampoline_mass. - Migrate the existing hopping controller from IsaacGym to Isaac Lab.
- Adapt the existing humanoid (G1) whole-body motion tracking pipeline for quadruped (Go2) use.
- Integrate trampoline into training with domain randomization over
Task 2: Custom contact model
- Replace trampoline with customized contact model.
Taks 3: Compliant-contact TO
Isaaclab Trampoline
ball - 8e3
g1 - 8e3
go2 - 8e4
g1 - 8e4
Custom contact model
ball - normal force only
go2 - normal force only
ball
go2
Compliant-contact TO
rigid ground
Hopping Reward Design
phase contact
Flight Time: Green - 0.55s Purple - 0.65s
Hopping Reward Design
joint deviation
Zero Velocity
meeting