| A concept of distributed actuators and their controls for high-speed, high-acceleration, material transfer network based upon linear induction machines (LIMs) was studied here. The actuators consisting of modularized stationary primaries are connected to form a distributed, closed guideway structure with multiple access ports along the path. High-speed vehicles (moving secondaries of the LIMs) are continuously recirculating inside the loop, loading/unloading manufacturing system elements as requested via access ports.; The material transfer network could be conceptually analogous to a computer system network. With substantially increased acceleration rate ({dollar}sim{dollar}3g or 30 m/s{dollar}sp2{dollar}), transfer speed ({dollar}sim{dollar}120 km/hr or 33 m/s), multi-dimensional moving capability, full closed-loop motion controls and electromagnetic steering/switching, the system is able to deliver material/parts/tooling from point to point in seconds rather than minutes as required in conventional AGV and conveyor systems. This makes the transfer time to be negligible and enables the system to more effectively and economically utilize the available resources. Correspondingly, it provides significant potential savings by reducing process delays, work-in-process inventories and tool redundancy.; To achieve high acceleration and speed, the transfer network features an integrated electromagnetic propulsion system and vehicle design with fixed primaries/moving secondaries LIM configuration. To accomplish electromagnetic steering/switching for multi-dimensional movements without the use of additional ground mechanism, the transverse flux LIM topology is implemented. By using field orientation controls with feedforward decoupling, vehicle motion controls can be readily achieved by decoupled thrust and normal force controls.; In this study, a multi-unit TFLIMs testbed was also constructed to assure the design and manufacturing feasibility, model development and controller design and verification. The testbed consists of one curvilinear TFLIM unit with 1 m turning radius and three straight TFLIMs extending over a {dollar}5spprime{dollar} x 11{dollar}spprime{dollar} ground footprint. With this configuration, we are able to demonstrate the performance for both linear and curvilinear motion controls. The experimental results indicated a promising outcome of this new technology over conventional and other LIM-based material transfer systems. |
