Issue 39 Unmanned Systems Technology August/September 2021 Maritime Robotics Mariner l Simulation tools focus l MRS MR-10 and MR-20 l UAVs insight l HFE International GenPod l Exotec Skypod l Autopilots focus l Aquaai Mazu

34 S imulation is becoming an increasingly important part of the development and qualification of autonomous system designs, and is even making its way into predicting their operation. Simulation technology has always been part of the development process. Silicon chips for example are simulated extensively to ensure they will run correctly in autonomous systems. CFD simulation models the airflow around a virtual UAV, to demonstrate the performance of a design without having to pay for expensive time in a wind tunnel, and it can also model the flow of fluid through a fuel cell. Increases in computing power derived from thousands of the latest processors in the cloud is enabling larger systems to be accurately simulated. However, there is a complex trade-off between the time taken to generate a simulation, the cost of the processing and the level of detail that can be achieved. Simulations that are accurate to each cycle of a controller are possible, but they take a lot of processing power and time to produce. Higher-level models that describe the general behaviour of a component run much faster, providing details about real-time performance but with less resolution. Ensuring that these behavioural models are the same as the cycle-accurate models, and being able to swap quickly and easily between them, is another challenge for simulation environment developers. Simulation software is definitely catching up now though. Entire vehicles, from the silicon chips upwards, can be simulated in the cloud. The same complete design can be tested for electromagnetic interference using both near- and far-field simulations with the latest EM solvers. This complete model, or digital twin, is expensive to build, especially for driverless cars. It pulls together complex models of sensors, with multiple cameras, Lidar and radar sensors that handle gigabytes of data, control units, braking and battery systems. Sensor Simulation is expanding to model every part of an unmanned system, reports Nick Flaherty , who examines the latest developments in the software Role models August/September 2021 | Unmanned Systems Technology The latest version of the AIsim tool enables accurate simulation of multiple independent vehicles (Courtesy of AImotive)