One of the key components of Team Tennessee’s EcoCAR 2 Malibu is the controls architecture. The University of Tennessee controls team has chosen a dSPACE MicroAutoBoxII for its Supervisory Control Module (SVC), the center of its vehicle’s controls architecture. The MicroAutoBoxII is programed with control logic built in Matlab Simulink. As the name implies, the SVC takes inputs from the driver and many vehicle electronic control units (ECUs), then calculates the appropriate controller response and commands it from the applicable ECU. The SVC is like the conductor of an orchestra, bringing together the talents of individuals to create one harmonious song. Each ECU is specialized to control its own area, but the SVC commands all the ECUs so that they work together to produce an efficient and safe vehicle.
The SVC is particularly responsible for deciding the vehicle’s running mode (conventional, series hybrid or parallel hybrid). The logic to determine the appropriate running mode is primarily based off the vehicle, speed, the battery’s state of charge and the driver’s power demand. Once the vehicle mode is chosen, the SVC commands torque from the appropriate vehicle components. For example: in the case of parallel hybrid mode, the power demanded from the driver via throttle position is interpreted, split between the engine and rear traction motor and finally commanded from these components via CAN networking.
In addition to component control, the supervisory controller also provides the vehicle with fault recognition and mitigation. Fault logic is created to quickly recognize potentially dangerous vehicle conditions and perform the necessary steps to ensure driver and vehicle safety. An example is the logic that monitors the CAN network. If a problem is detected, the vehicle enters a type of “safe mode” to ensure that the failure does not cause a potential loss of vehicle control.
As the controls team continues to develop the communication and fault logic, the controls architecture was being increasingly tested to ensure a smooth integration into the vehicle. The team will spend Year Three perfecting this integration – we can’t wait to see how it turns out!