Design, implementation, and evaluation of a real-time kernel for distributed robotics

Modern robotics applications are becoming more complex due to greater numbers of sensors and actuators. The control of such systems may require multiple processors to meet the computational demands and to support the physical distribution of the sensors and actuators. A distributed real-time system is needed to perform the required communication and processing while meeting application-specified timing constraints. Our research is the design and evaluation of a real-time kernel, called TimixV2, for distributed robotics applications. TimixV2 provides threads with dynamic timing constraints, execution environments as basic units for resource allocation and memory management context, and events to signal message arrival, device interrupts, alarms, and exceptions. The salient features of TimixV2 are support for uniform scheduling and timely communication. TimixV2 uses the notion of consistent scheduling to uniformly schedule both application and kernel threads to guarantee that the application\u27s real-time constraints are met. All device interrupt handlers, except the periodic clock interrupt, are converted to threads that are scheduled like any other thread. TimixV2\u27s port-based message passing primitives support real-time communication by allowing individual message priorities to be used to order messages on a queue and by propagating scheduling information from a message to the associated thread on message arrival. The kernel has been implemented on a distributed test-bed and evaluated with respect to distributed real-time robotics applications