Tham khảo tài liệu 'challenges and paradigms in applied robust control part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Robust Control Design for Automotive Applications A Variable Structure Control Approach 79 10 5 0 -5 0 5 -10 -5 0 -5 -10 -10 10 Fig. 6. Nonlinear simulation results for example in 2 with second order sliding mode control law in 5 sampling time ts 20 ms phase portrait of closed-loop system up left zoom-in of phase portrait up right system states X1 blue and X2 red low left and control input u low right 3. Nonlinear engine model In this section a mathematical model of the spark ignition SI engine is briefly discussed. In the remainder of this contribution this engine model will basically be used as a nonlinear simulation model and thus as virtual engine test rig. It incorporates both the overall system dynamics of the engine and the torque structure of current engine management systems. For modeling purposes of the engine a continuous time mean value modeling approach turned out to be sufficient at idle condition Guzzella Sciarretta 2005 . This means that all internal processes of the engine are spread out over one combustion period and differences from cylinder to cylinder are neglected. Thus it is sufficient to take only the electronic throttle with its position controller the intake manifold and the rotational dynamics of the crankshaft into account a thr 1 1 . athr I . athr u Tthr Tthr p im R mthr - mcc Vim 9 N nJ Tind Tloss Tload where Tthr represents the time constant of the closed loop behaviour of the electronic throttle. The variables mthr mthr Pim athr u and mcc mcc Pim N denote the air mass flow rates into the intake manifold and the combustion chamber respectively. For the calculation of the indicated torque Tịnd Tind mCc Tign u t Td per combustion cycle the air mass flow 80 Challenges and Paradigms in Applied Robust Control rate into the combustion chamber has to be related to the crank-angle domain based software features of the electronic control unit m Cc 120 NccNmcc . 10 Additionally the physical actuator inputs throttle position athru and ignition .
