Force Display for Inter-Atomic Bonds Using a Parallel Wire Drive System

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The aim of our research is to develop a force display device for the inter-atomic bonding state and its control algorithm. The final goal of this research is to aid scientists by improving the perceptibility of data describing the atomic world. During the term of 1997, we completed a prototype of a 6-DOF manipulator that uses a parallel wire drive system. In 1998, the control system was produced and its algorithm was studied. Basing the experiments presented herein on our previous research, we obtained the following results.1. A 6-DOF force display device using a parallel wire drive mechanism was developed. When holding a ball called an atom ball, the operator can feel the motion and the bonding state of an atom. The inertial moment of the manipulator can be reduced by using a parallel wire drive system with seven wires. Thus, high speed 6-DOE motion is possible, though accurate position control is difficult because the control performance is affected by fluctuation of wire tension equilibrium.2. The decision procedure of the scaling factors between the atomic and human worlds was proposed, and the control algorithm for the force display was studied. The validity of the procedure was proved by an experiment with atomic bonding states using a l -DOF force display device. We adopted an empirical inter-atomic potential for the atomic bonding state and a molecular dynamic method for atomic behaviors. Based on the applied force from the operator to the atom, the atom position of the next time period is computed by using the molecular dynamic method. Then the next atom position is used as the desired position for the feedback control of the force display device.With regard to future research, we recommend that further experiments using the 6-DOF force display system be conducted.