Dual-servo control for conveyor induction systems

摘要

A conveyor system including an induction subsystem for producing a desired spacing between packages as they are discharged from a single induction line or merged from multiple lines. Each induction line includes a conveyor and a speed controller for controlling the running speed of the conveyor in a manner that discharges a package as close as possible to a time necessary to provide a desired gap with a previously-discharged package. Each induction line is operated by two servo-controlled motors, with the speed of the downstream motor being controlled in a manner that will provide desired spacing between inducted packages and with the speed of the upstream motor being controlled as a selectable ratio to the speed of the downstream motor. This provides an initial controllable gap between packages to reduce the range of gaps experienced by the induction control. In another embodiment, a sortation subsystem is operated at a higher line speed than the induction subsystem from which it receives packages. The induction subsystem establishes gaps between packages taking into account the increase in line speed and package lengths so that the gaps are of desired length at the sortation subsystem.