Open-source ROS-based simulation for verification of FPGA robotics applications

FPGAs are increasingly incorporated in many high-end robotics applications, often involving computer vision and motor control. However, functional verification of FPGA designs is labor-intensive, time-consuming, and consequently expensive. Moreover, validation of complex systems, such as robots, poses even further challenges because neither the external interactions can be easily modeled with traditional testbenches nor the robot's response can be adequately observed and ascertained. This work presents anew methodology that validates the robot's behavior in a realistic simulated environment before transferring the design to the physical robot and the onboard FPGA. This methodology allows integral, fast, and flexible debugging cycles of robotics applications by integrating the functional simulation of the processing unit (FPGA) with the simulation of the robot, its environment, and their mutual interconnections. The Verilator simulation tool is used for fast Verilog/SystemVerilog verification and simulation. ROS, the standard robotics middleware, and Gazebo 3D robotics simulator are used for realistic robot simulation, including a robust physics engine. We have implemented several open-source software extensions to interconnect the Verilog circuit with the simulated ROS sensors and actuators. This methodology's utility and correctness have been assessed by developing a complete proof-of-concept FPGA-based robotics application in which a commercial robot follows a colored object using its onboard camera and differential drive motors. This work establishes the foundations for developing and testing complex robot FPGA-based modules more efficiently and flexibly.