In order to meet performance, efficiency, emission and other possible requirements over a wide range of operating conditions and environments, an automotive system may have more input variables than output variables. The input variables to a plant, controlled using actuators, are used to control the output variables of the plant process. For example, a conventional gasoline engine will have at a minimum, throttle, spark advance and fuel inputs in order to control the speed and/or the air/fuel ratio of the engine. The excess of inputs, and thus excess of actuators, is desirable in attempting to improve performance, efficiency, and the lice. And although these features of a control system may not be reflected through variables that are controlled to a specific set point, the features are important with respect to obtaining the best operation of an engine or plant. However, a cost effective and practical control system, method of design and/or strategy that optimizes an overall force, moment or generalized effect using actuators of the system is lacking. Therefore, a control system for over-actuated systems in which the individual features of the various actuators are incorporated to provide optimized inputs to a plant is desirable.
Researchers at the University of Michigan have invented a method and system that can simultaneously control actuators to optimally regulate an engine variable to a particular set point. This method determines the ability of the actuators to change the engine variable and also determines the capability of the actuators to reject a disturbance. The engine control system described in this invention uses at atleast two actuators that regulate one or more engine variables, where the number of engine variables is less than the number of actuators.
Applications and Advantages
- Automotive systems such as vehicle power train systems, vehicle stability control systems
- Aircraft systems
- Robotic systems
- Division between plant and actuator subsystems can depend on a choice of virtual control inputs
- Very cost effective