Toyota adopted MathWorks tools like MATLAB, Simulink, Simulink Coder, and Stateflow, as a total design solution.
Toyota’s initiative—and their development partnership with MathWorks—was set in motion when the auto maker first chose MATLAB, then Simulink. “Our use of [these tools] has been gradually increasing,” says Toyota spokesperson Akira Ohata. “We now have more than 400 licenses for MATLAB, Simulink, and Stateflow, and they have become the de facto standard at Toyota for simulation, data processing, and controls design. It would be impossible to list all of the applications for these tools at Toyota.”
MathWorks tools have found a real home in the development of Toyota’s electrical control units (ECUs), the under-dash controllers that run the software that runs the vehicles. Faced with stringent emissions standards and calls for improved performance, Toyota engineers are concentrating on improving such vital logic as fuel injection and transmission controls.
With design solutions from MathWorks, Toyota engineers have the significant advantage of designing, modeling, simulating, testing, and programming control strategies in a single environment. For example, specifications for Toyota’s powertrain controllers now begin in the intuitive and self-documenting environment of Simulink and Stateflow, both powered by the industrial-strength computational, analytical, and visualization capabilities of MATLAB.
Controls engineers work directly in these executable specifications, refining control strategies and optimizing performance. The engineer’s work is then just a step away from working C code through Simulink Coder, with software coded per the control engineer’s intent.
Toyota engineers use the code in conjunction with hardware and implementation software manufactured by dSPACE of Germany for testing and virtual prototyping. Toyota takes advantage of two types of simulation: hardware-in-the-loop (HIL) simulation, which allows testing of a prototype ECU on a “virtual engine” modeled in Simulink, and rapid prototyping ECU (RPE), which allows the simulator to replace all or part of the ECU while controlling an actual power plant.
Toyota uses HIL with the Simulink virtual engine to debug ECU hardware and software and for calibration. The HIL setup reduces costs, makes it easy to analyze performance, and allows duplication of operating conditions such as cold start and warmup. In RPE, Toyota engineers can calibrate the parameters of control algorithms and quickly evaluate control logic. Developers build control logic in MATLAB and evaluate it with Simulink, finding the most promising candidates.
Through the use of dSPACE hardware, the changed parts of the engine control can be segregated as the ECU controls a real auto power plant. This allows the engineers to concentrate on areas being improved or developed.