Development of modular real-time software for the TALARIS lunar hopper testbed

Abstract

Hoppers have recently emerged as a viable means for planetary exploration, and as with any new vehicle, significant testing is required to validate guidance, navigation, and control (GNC) algorithms. Furthermore, the structure, organization, and timing of the real-time software must be planned before software development begins in order to design an architecture which can match the needs and requirements of the vehicle as they evolve throughout its lifecycle. These issues are compounded in an academic environment, where software knowledge is not necessarily present and must be obtained and practiced before it can be applied. In addition, high student turnover rates can result in difficulty retaining institutional knowledge of the working software and causes further development delays while new students are trained. These problems were addressed by the TALARIS software team by implementing a flexible, modular software solution in LabVIEW on the National Instruments Real-Time Input/Output (RIO) board. After a brief introduction to the TALARIS testbed, the theory of flexibility and modularity is described as applied to the TALARIS software. In particular, the unique FPGA + PowerPC architecture and its importance to precise, real-time GNC execution are explored. Various software modules are isolated and analyzed, and several test cases are presented to illustrate the benefits of modular software with regard to development time, testing procedure, and debugging. Examples from software development, actuator characterization, and test campaigns illustrate the gradual evolution of the prototype software. Finally, a discussion of the conclusions from the work and future work is presented.