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As both the number and complexity of electronic control system applications on earthmoving equipment and on-highway trucks increase, so does the effort associated with developing and maintaining control strategies implemented in embedded systems. A new tool was recently introduced by Sigma Technology of Ann Arbor, Michigan, that provides the capability to perform rapid prototyping of production embedded systems. The rapid prototyping process includes system modeling, control algorithm synthesis, simulation analysis, source code generation and vehicle implementation. The results of incorporating this tool in the control system design process include improved control performance, improved system reliability/robustness, and significantly reduced development/maintenance costs.

This paper identifies potential performance benefits and computational costs of applying advanced multivariable control theory concepts to coordinate the control of a general multi-degree-of-freedom fuel system. The control variables are injection duration and pressure. The focus is on the design of a robust multi-input multi-output controller using H-infinity and mu synthesis methodology to coordinate the control of injection duration and pressure; reduce overshoots and system sensitivity to parameter variations caused by component aging. Model reduction techniques are used to reduce the order of the H-infinity controller to make it practically implementable. Computer simulation is used to test the robust performance of a generic engine and fuel system model controlled by the reduced order H-infinity controller and a traditional proportional plus integral controller.

The rapid prototyping process outlined in [1] has been updated to reflect the automotive industry's turn toward 32-bit embedded hardware and “C” software as well as enhancements in commercially available rapid prototyping systems. To exploit these advancements, Caterpillar, Inc. and Integrated Systems, Inc. (ISI), partnered to develop a PC-based rapid prototyping computer which provides the capability to rapidly test alternative control strategies using production-intent embedded system hardware (H/W) and software (S/W). The tool significantly improves the ease and reduces the experience level required by non-control system engineers employing the rapid prototyping process [1] and provides a stepping stone toward direct application of automatically generated C code to production embedded systems.