A Hardware-in-the-Loop Test Platform for Planetary Rovers

Hardware-in-the-Loop (HIL) test platform for planetary rovers was designed, fabricated and tested in \nthe present work. The ability for planetary rover designers and mission planners to estimate the rover’s \nperformance through software simulation is crucial. HIL testing can further the benefits of software \nsimulations by allowing designers to incorporate hardware components within traditionally pure software \nsimulations. This provides more accurate performance results without having access to all hardware \ncomponents, as would be required for a full prototype testing. \nThe test platform is designed with complete modularity such that different types of tests can be \nperformed for varying types of planetary rovers and in different environments. For demonstrating the \noperation of the test platform, however, the power system operation of a solar powered rover was \nexamined. The system consists of solar panels, a solar charge controller, a battery, a DC/DC converter, a \nDC motor and a flywheel. In addition, a lighting system was designed to simulate the solar radiation \nconditions solar panels would experience throughout a typical day. On the software side, a library of \ncomponent models was developed within MapleSim and model parameters were tuned to match the \nhardware on the test bench. A program was developed for real-time simulations within Labview allowing \ncommunication between hardware components and software models. This program consists of all the \ncomponent models, hardware controls and data acquisitioning. The GUI of this program allows users to \nselect which component is to be tested and which component is to be simulated, change model parameters \nas well as see real time sensor measurements for each component. A signal scaling technique based on \nnon-dimensionalization is also presented, which can be used in an HIL application for obtain scaling \nfactors to ensure dynamic similarity between two systems. \nA demonstration of power estimation was performed using the pure software model simulations as \nwell as the pure hardware testing. Hardware components were then added into the software simulation \nprogressively with results showing better accuracy as hardware is added. The rover’s power flow was also \nestimated under different load conditions and seasonal variation. These simulations clearly demonstrate \nthe effectiveness of an HIL platform for testing a rover’s hardware performance.