A new design for humanoid arms is presented based on a tripod mechanism that is actuated by linear servomotors. A specific prototype is built and tested, with the results of performance characterization verifying a possible implementation on the LARMbot humanoid. The design solves the main requirements in terms of a high payload ratio with respect to arm weight by using a tripod architecture with parallel manipulator behavior. The built prototype is assembled with commercial components to match the expectations for low-cost user-oriented features. The test results show satisfactory operation characteristics both in motion and force performance, which will ensure a future successful implementation in the LARMbot humanoid structure.
