From Ellipsoids to Midair Control of Dynamic Hitches

2026-02-08

AI Summary

This work proposes a method for dynamically constructing a controllable “rope hitch” structure through cooperative manipulation by multiple aerial robots, enhancing the flexibility and agility of cable-assisted aerial operations. The hitch morphology formed by two entwined cables is characterized using an ellipsoidal geometric model, which is then integrated with the quadrotor dynamics to establish a control-affine relationship. For the first time, ellipsoidal geometry and hitch dynamics are unified to design a composite error that renders the system relative degree one. A quadratic programming-based CLF-HOCBF controller—combining Control Lyapunov Functions and High-Order Control Barrier Functions—is employed to rigorously enforce safety constraints such as cable tension limits. Simulations demonstrate that the proposed approach achieves precise tracking of both hitch position and shape under high-speed dynamic trajectories while guaranteeing system stability and safety.

Technology Category

• Intelligent Robots: Manipulation
• Planning, Routing, and Scheduling: Replanning and Plan Repair
• Humans and AI: Human-Aware Planning and Behavior Prediction

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Economics, Online Markets and Human Computation: LLM based quality controls for crowd work
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

The ability to dynamically manipulate interaction between cables, carried by pairs of aerial vehicles attached to the ends of each cable, can greatly improve the versatility and agility of cable-assisted aerial manipulation. Such interlacing cables create hitches by winding two or more cables around each other, which can enclose payloads or can further develop into knots. Dynamic modeling and control of such hitches is key to mastering the inter-cable manipulation in context of cable-suspended aerial manipulation. This paper introduces an ellipsoid-based kinematic model to connect the geometric nature of a hitch created by two cables and the dynamics of the hitch driven by four aerial vehicles, which reveals the control-affine form of the system. As the constraint for maintaining tension of a cable is also control-affine, we design a quadratic programming-based controller that combines Control Lyapunov and High-Order Control Barrier Functions (CLF-HOCBF-QP) to precisely track a desired hitch position and system shape while enforcing safety constraints like cable tautness. We convert desired geometric reference configurations into target robot positions and introduce a composite error into the Lyapunov function to ensure a relative degree of one to the input. Numerical simulations validate our approach, demonstrating stable, high-speed tracking of dynamic references.

Problem

• aerial manipulation
• dynamic hitches
• cable tension
• midair control
• inter-cable interaction

Innovation

• ellipsoid-based kinematic model
• dynamic hitches
• control-affine system
• CLF-HOCBF-QP
• cable-suspended aerial manipulation