DAG-Based QoS-Aware Dynamic Task Placement for Networked Multi-Stage Control Pipelines

TL;DR

This paper introduces a DAG-based QoS-aware dynamic task placement framework for multi-stage control pipelines in networked robotics, aiming to optimize latency, utilization, and stability.

Contribution

It proposes a novel DAG formalization and a window-based cost function for adaptive, multi-stage task placement with switching penalties in industrial robotic pipelines.

Findings

Framework formalizes pipeline as a DAG with detailed attributes.

Cost function combines latency, violation rate, utilization, and switching penalties.

Validation roadmap includes simulation and hardware-in-the-loop testing.

Abstract

Current Physical AI (PAI) relies heavily on closed-loop visual-servoing pipelines, whose perception and planning stages may become computationally intensive onboard due to complex models embedded on robots. In practice, offloading the perception task to on-site edges statically is inappropriate for latency-sensitive, precise industrial settings over a standardized industrial network. This emphasizes the importance of Control-Communication-Computing (3C) co-design in industrial automation: monolithic local execution saturates AI-accelerated machine and robot hardware, while static edge offloading exposes the control loop to network jitter. Existing adaptive task placement (ATP) controllers can partially address the gap by relocating a single pipeline stage on binary threshold rules, without a multi-stage model and an explicit cost on placement switching. In this Work-in-Progress (WiP) paper, we propose a directed acyclic graph (DAG) based quality-of-service (QoS)-aware dynamic task placement (DTP) framework for sensing-perception-planning-control pipelines in networked robotics. This pipeline is formalized as a DAG with task-level and node-level attributes for compute cost, communication delay, and feasible placement sets; over a small interpretable candidate set (fully local, static offload, hybrid), a window-based cost function combines tail end-to-end latency, deadline violation rate, hardware utilization, and a Hamming-distance switching penalty, and a DTP algorithm with hysteresis and a minimum dwell-time bounds placement chatter. Our WiP paper presents the theoretical framework, a structured qualitative analysis, and a two-phase simulation plus hardware-in-the-loop validation roadmap.