Control of pneumatic artificial muscles with the just-in-time method based on a client-server architecture via the internet

This paper proposes the concept of “networked JIT control” based on a client-server architecture via the Internet, which is an expanded version of the Just-In-Time (JIT) control. In the proposed concept, the server has a database for the JIT control and the client has a plant to be controlled. The server performs the computation of an inverse model of the plant by utilizing data stored in the database. The client executes a feedback control algorithm, communicates data for the JIT control with the server through the Internet, and feeds control commands to the plant. In addition to the general advantages of the JIT control, this concept enables to share the database on the server with the clients and to reduce the costs of the addition of more clients. A control system of a robot manipulator driven by pneumatic artificial muscles, which are elastic and safe for humans but nonlinear and difficult to model, is constructed based on the proposed concept. Experimental results show that data obtained by communicating with the server lead to an improvement in the control performance and that the proposed concept is realizable.