In this paper, a deburring tool with 3-axis compliance is presented for deburring using a robot manipulator. Compliance is provided with beam structures instead of pneumatic pressure, which enables integrated 3-axis force sensing and variable stiffness. Two radial compliances were achieved using 4-PSS (Prismatic-Spherical-Spherical) legs, with P joints composed of cantilever beams. The one axial compliance was configured with two ball bushings and a linear spring. Strain gauges were attached to cantilever beams and a load cell was mounted between the linear spring and the universal joint to perform force sensing. The stability of vibrations and force sensing were verified through deburring experiments using the proposed deburring tool. Additionally, experiments on automatic offset for applying a constant force during deburring were conducted and results were validated by comparing the workpiece before and after the deburring process.

This paper presents a robot hand inspired from grasp and grip mechanism of human hand. In human hand, grasp and grip are different terms: Human hand can grasp an object adaptively by individual pulling of each finger’s tendon. Once the fingers make contact with the object, the human hand can grip the object with a larger force by simultaneous pulling of the tendon of each finger. Inspired from this, we propose a mechanism decoupling flexion drive and force-magnification drive for a wire-driven robot hand. The flexion drive consists of electric motors pulling the wire of each finger to make adaptive movement of the robot hand (grasp). The force-magnification drive consist of a hydraulic cylinder that pulls the wire of each finger simultaneously (grip). We also propose adaptive grasp mechanism using spring linkage. It is possible to grasp the irregular objects of limited size without a complex control algorithm or sensor system. We experimentally verified that the grip force of the prototype robot hand exceeds 300N which is 10 times larger than the electric motor alone.

Recently, there are numerous studies on robots to function with smoother movement and high efficiency. It is difficult to develop robots with smooth movement and high efficiency. To solve this problem, the Series Elastic Actuator (SEA) is used. It is an actuator that gives compliance to a general actuator. Presence of compliance will bring to advantages. First, robots can reduce external impact force with high compliance. Second, the force of SEA can be controlled more precisely, than a normal actuator. Some SEAs have been developed with many functions, but the structure is complicated. So, in this study, the SEA with compact and simple structure was proposed. Shape of the SEA is cylindrical, and its diameter, height and weight are 70mm, 338mm, and 2.5kg respectively. The SEA was modeled in a two-degree of freedom mass spring damper system. To demonstrate travel response characteristics of the SEA, experiments were conducted and the result revealed design of the SEA is validated.