Proterra decided to leverage a Hardware-in-the-Loop (HIL) development approach to aid the testing and development of the control systems for the new transit bus.
HIL allows control systems to be thoroughly tested in the lab by simulating vehicle components including sensors and communications that would normally provide data from the real world. Simulation allows complete control of the inputs to the control system, and so allows tests to be performed rapidly and easily. Proterra decided to use Speedgoat solutions for HIL, as its systems are expressly designed for use with Simulink.
Proterra developed a real-time application with Simulink, to run all the major vehicle components, the vehicle’s extensive CAN protocol networks, and all the digital and analog I/O, including temperatures, pressures and speeds. For example, pulse signals were used to simulate the speed of the fans found in the cooling subsystems of the bus, and to simulate feedback related to the status of the vehicle components such as doors, low voltage contactors, and the gearbox.
To run the real-time application, a Speedgoat Performance real-time target machine was used, providing all required I/O and communications protocols.
The target machine was chosen for its powerful Intel CPU, its flexibility, and its ability to support a wide range of I/O connectivity. The project was a great success with Proterra praising the seamless integration of Speedgoat and MathWorks tools.