Push, Press, Slide: Mode-Aware Planar Contact Manipulation via Reduced-Order Models

Abstract

Non-prehensile planar manipulation, including pushing and press-and-slide, is critical for diverse robotic tasks, but notoriously challenging due to hybrid contact mechanics, under-actuation, and asymmetric friction limits that traditionally necessitate computationally expensive iterative control. In this paper, we propose a mode-aware framework for planar manipulation with one or two robotic arms based on contact topology selection and reduced-order kinematic modeling. Our core insight is that complex wrench-twist limit surface mechanics can be abstracted into a discrete library of physically intuitive models. We systematically map various single-arm and bimanual contact topologies to simple non-holonomic formulations, e.g. unicycle for simplified press-and-slide motion. By anchoring trajectory generation to these reduced-order models, our framework computes the required object wrench and distributes feasible, friction-bounded contact forces via a direct algebraic allocator. We incorporate manipulator kinematics to ensure long-horizon feasibility and demonstrate our fast, optimization-free approach in simulation across diverse single-arm and bimanual manipulation tasks.

Figures (13)

• Figure 1: A single arm uses press-and-slide to transport an object, then leverages it as a tool to reposition a second object.
• Figure 2: Kinematic abstractions of single-arm rear pushing. (a) Symmetric pushing yields a Rear-Wheel Steering (RWS) model. (b) A lateral offset introduces a bias, distorting the steering envelope.
• Figure 3: Single-arm top press-and-slide. The virtual axle lies on the longitudinal axis for symmetric contacts (a) and diametrically opposite the CoM for unsymmetric contacts (b).
• Figure 4: Top press-and-slide motion admits a planar force-invariant, body-fixed tracking point. This geometric point remains kinematically valid for all applied planar forces within the 2D friction circle; and acts like a virtual axle, allowing motion planning as a unicycle, car, or forklift.
• Figure 5: Dual-arm rear pushing collapses into an Equivalent Bicycle model (a) via synchronized forces, or a Differential Drive model (b) via pure differential normal forces.