THE CHIMERA-II REAL-TIME OPERATING SYSTEM FOR ADVANCED SENSOR-BASED CONTROL APPLICATIONS

The Chimera II Real-Time Operating System, which has been developed for advanced sensor-based control applications. It has been designed as a local operating system, to be used in conjunction with a global operating system, is described. It executes on one or more single board computers in a VMEbus-based system. Advanced sensor-based control systems are both statically and dynamically reconfigurable. As a result, they require many special features, which are currently not found in commercial real-time operating systems. Several design issues for such systems are presented as well as the features we have developed and implemented as part of Chimera II. These features include a real-time kernel with dynamic scheduling, global error handling, user signals, and two levels of device drivers; an enhanced collection of interprocessor communication mechanisms, including global shared memory, spin-locks, remote semaphores, priority message passing, global state variable tables, multiprocessor servo task control, and host workstation integration; and several support utilities, including UNIX C and math libraries, a matrix library, a command interpreter library, and a configuration file library. Chimera II is currently being used with a variety of systems, including the CMU Direct Drive Arm II, the CMU Reconfigurable Modular Manipulator System, the Troikabot System for Rapid Assembly, and the Self-Mobile Space Manipulator.