Learning-Based Robotics
Bridging learning-based policies with real-time robotic systems requires handling multimodal action distributions and deterministic sim-to-real domain randomization.
What is one-shot / few-shot imitation learning, and how would you apply it to a cobot task?
One-shot imitation learning parameterizes robot trajectories using **Dynamic Movement Primitives (DMPs)**. A single kinesthetic human demonstration is encoded as a set of non-linear differential equations:
where $f(x) = \frac{\sum w_i \psi_i(x)}{\sum \psi_i(x)} x$ is a forcing function learned via linear regression over radial basis functions $\psi_i(x)$. Adaptations to new target object poses $g_{\text{new}}$ are executed analytically by updating goal parameters in real time without retraining network weights.
Where do diffusion models fit into robotics beyond image generation?
Diffusion Policies represent robot action distributions $p(a|o)$ as an iterative denoising process. Unlike Gaussian MLP policies which average multiple valid grasp trajectories into an invalid middle collision path, Diffusion Policies represent multimodal distributions effectively:
To run real-time at $20\text{Hz}$, policies use **DDIM sampling** (reducing denoising steps from 100 to 5) coupled with TensorRT INT8 optimization on Nvidia Jetson Orin hardware.
How would you use a genetic algorithm in a robotics context?
Genetic Algorithms (GA) optimize non-differentiable trajectory parameters or controller gains in physics simulation (Isaac Gym / Gazebo). Chromosomes encode controller parameters $P = [K_p, K_i, K_d, \phi_{\text{phase}}]$. Evaluation runs 1000 parallel environments testing candidate survival against fitness function $F = -\int (e^2 + w_u u^2) dt$. Best candidates undergo **Sim-to-Real Domain Randomization** (varying ground friction $\mu \in [0.2, 1.2]$, motor payload $m \pm 30\%$, latency delay $t_{\text{delay}} \in [0, 20\text{ms}]$) before deployment to hardware.