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In a math-based control algorithm design, model-based simulation and testing are very important as an integral part of design process. There are many advantages of using modeling and simulation in the algorithm design. In this paper, Algorithm-in-the-Loop and Hardware-in-the-Loop approaches are adopted for a transmission control algorithm development. A practical approach is introduced on how to test the control algorithms with a reliable plant (virtual engine, transmission, and vehicle) model in the closed-loop simulation. In using combination of open-loop and closed-loop simulations, various key behavior test cases are developed and documented for the success of control algorithms development. Secondly, the same test cases are reused and verified against the production codes, which are automatically generated from the math-based control algorithm models.

A math-based approach is now in use to reduce transmission control algorithm development time and prototyping iterations, and to improve transmission control algorithm and software quality. This paper will describe the application of this efficient approach to the development of a transmission control algorithm for production. The processes for algorithm design, closed-loop and rapid prototype testing, auto-code generation of production software, and potential hardware-in-the-loop verification are described with references to supporting development tools. This approach enables upfront, math-based development and performance assessment of transmission control algorithms and their interactions with other powertrain and vehicle control algorithms. Examples will illustrate the efficiency of the control algorithm development approach over a wide range of conditions.