Design and testing of BACCOs, a gravity-compensated robotic manipulator for wine sampling

Purpose This paper aims to present the design, modeling and experimental validation of Automatic Collection and Conveyance of Oenologic Samples (BACCOs), a low-degree-of-freedom (DOF), gravity-compensated robotic manipulator for automated wine sampling. This study focuses on the mechanical design of a four-DOF robotic arm, intended to be mounted on a two-DOF mobile platform to perform autonomous sampling operations. Design/methodology/approach To meet the specific requirements of the application, the robotic arm design incorporates a planar double-parallelogram mechanism for end-effector positioning, along with two additional joints to compensate for pose errors of the mobile base. Two independent passive gravity-compensation systems, namely, a spring-wire system and a spring-wire-cam system, are implemented to enable energy-efficient operation of the double-parallelogram mechanism and the use of low-power actuators. Findings The robotic arm has been built and experimentally tested in a laboratory environment, demonstrating the effectiveness of the gravity-balancing systems. Originality/value The proposed design satisfies the key application requirements, particularly the need for a large workspace (in fact, barrel taps are typically located between 1.1 and 1.81 m above floor level and within corridors up to 2 m wide), while ensuring a lightweight and energy-efficient solution. Moreover, the paper presents a modified graphical method for the design of the cam used in one of the gravity-compensation systems, building on previous literature on cam design.