Embedded Real-Time Linux for Cable Robot Control

摘要

Linux is a version of the Unix operating system distributed according to the open source model. Programmers are free to adapt the source code for their purposes, but are required to make their modifications or enhancements available as open source software as well. This model has fostered the widespread adoption of Linux for typical Unix server and workstation roles, and also in more arcane applications such as embedded or real-time computing. Embedded applications typically run in small physical and computing footprints, usually without fragile peripherals like hard disk drives. Special configurations are required to support these limited environments. Real-time applications require guarantees that tasks will execute within their deadlines, something not possible in general with the normal Linux scheduler. Real-time extensions to Linux enable deterministic scheduling, at task periods at tens of microseconds. This paper describes embedded and real-time Linux, and an application for distributed control of a Stewart Platform cable robot. Special Linux configuration requirements are detailed, and the architecture for teleoperated control of the cable robot is presented, with emphasis on the resolved-rate control of the suspended platform.