Control of a wire-driven 7-DOF arm for miniature humanoid with gravity compensation model

In our previous work, a wearable robot named telecommunicator was developed. The telecommunicator can achieve rich communication with a remote person through a small robot. Until now, we have developed several types of the wearable telecommunicator T1, T2, T3, MH-1 and MH-2. The MH-2 has human like appearance with 7-DOF arms and a 3-DOF head. It employs a wire-pulley mechanism to achieve human-like movements. However, such a small wire-driven robot has drawbacks such as inexplicit wire path and twist of wire. To tackle these problems, we introduce a geometrical model which includes detailed wire paths. In addition, elastic rubber is employed into the wire to ease geometrical errors. Furthermore, we introduce a gravity compensation approach for the elastic rubber wires. To confirm the feasibility of the proposed method, a fundamental experiment is performed.