Design of a low-cost and lightweight 6 DoF bimanual arm for dynamic and contact-rich manipulation

--Dynamic and contact-rich object manipulation, such as striking, snatching, or hammering, remains challenging for robotic systems due to hardware limitations. Most existing robots are constrained by high-inertia design, limited compliance, and reliance on expensive torque sensors. T o address this, we introduce ARMADA (Affordable Robot for Manipulation and Dynamic Actions), a 6 degrees-of-freedom bimanual robot designed for dynamic manipulation research. ARMADA combines low-inertia, back-drivable actuators with a lightweight design, using readily available components and 3D-printed links for ease of assembly in research labs. The entire system, including both arms, is built for just $6,100. Each arm achieves speeds up to 6.16m/s, almost twice that of most collaborative robots, with a comparable payload of 2.5kg. We demonstrate ARMADA can perform dynamic manipulation like snatching, hammering, and bimanual throwing in real-world environments. We also showcase its effectiveness in reinforcement learning (RL) by training a non-prehensile manipulation policy in simulation and transferring it zero-shot to the real world, as well as human motion shadowing for dynamic bimanual object throwing. ARMADA is fully open-sourced with detailed assembly instructions, CAD models, URDFs, simulation, and learning codes. We highly recommend viewing the supplementary video at https://sites.google.com/view/im2-humanoid-arm. I NTRODUCTION Humans use a rich set of action repertoire to manipulate objects: we not only pick-and-place objects but also toss laundry, slide a box, snatch a pen, hammer a nail, otherwise arXiv:2502.16908v1 In contrast, most manipulators today are limited to picking, where a robot simply grasps an object to resist the frictional force. While kinematic pick-and-place is sufficient for static, controlled tasks, dynamic manipulation is necessary for building an effective general-purpose robot.