engine systems exercise class 9 - ethz.ch€¦ · refence: engine speed trajectory (in rad/s) load...
TRANSCRIPT
||
Pol Duhr, Hansi Ritzmann
Prof. Dr. Christopher Onder
18.11.2019 1Engine Systems
Engine Systems – Exercise Class 918/11/2019
|| 18.11.2019Engine Systems 2
ISCS – Milestones
# Milestone Deadline
1 Working Simulink model October 28th
2 Validated parameter identification November 11th
3 Working controller in simulation December 2nd
4 Working controller on test bench December 16th
||
Start: Last week
Complete: December 2nd (Monday in two weeks)
Tasks:
linearization
plant extension (integrative action)
LQG design
Deadline is fixed! Next step (controller testing) can only be done if you have a
controller!
18.11.2019Engine Systems 3
Milestone 3 – Controller Design
||
System should be normalized with the expected operating point:
Do not directly use data from the measurements
Think of reasonable operating conditions for your system
Run your simulation iteratively to obtain values for 𝑢𝛼 and 𝑝𝑚 that lead to a
reasonable speed 𝜔𝑒 for a given Δ𝑢𝜁
Do not include the load when normalizing
Reasonable nominal values:
18.11.2019Engine Systems 4
Normalization – Nominal Operating Point
𝑝𝑎𝑚𝑏 1 bar = 1 × 105 Pa 𝑢𝛼,𝑛𝑜𝑚 1.5…3 %𝜗𝑎𝑚𝑏 20 °C = 293 K Δ𝑢𝜁,𝑛𝑜𝑚 −40…− 10 °CA (more on next slide)
𝜗𝑚 𝜗𝑎𝑚𝑏 𝑝𝑚 0.2…0.4 bar𝑝𝑒 𝑝𝑎𝑚𝑏 𝜔𝑒,𝑛𝑜𝑚 70…200 rad/s
|| 18.11.2019Engine Systems 5
Normalization – Nominal 𝒅𝒖𝒊𝒈𝒏 Value
Δ𝑢𝜁,𝑛𝑜𝑚 = 0 ºCA
Δ𝑢𝜁,𝑛𝑜𝑚 = −20 ºCA
||
𝑢𝛼 slow actuator, “unlimited range” (0…100%)
Δ𝑢𝜁 fast actuator, limited range (Δ𝑢𝜁,𝑛𝑜𝑚…0)
Default test case: 𝜔𝑒,𝑑𝑒𝑠 = 𝑐𝑜𝑛𝑠𝑡. and load is turned on suddenly
Use Δ𝑢𝜁 to quickly increase the engine torque
Use 𝑢𝛼 to increase 𝑝𝑚 and return Δ𝑢𝜁 to Δ𝑢𝜁,𝑛𝑜𝑚 Regain fast acting controllability
18.11.2019Engine Systems 6
Control – Use of 𝒅𝒖𝒊𝒈𝒏 for Engine Speed Control
||
Only controllers with 1 input and 2 outputs are allowed
Refence: Engine speed trajectory (in rad/s)
Load is switched on and off randomly
Sampling time: 1 ms
To win the Pizza voucher: Minimize the cost function 𝐽
The cost function penalizes:
Deviations in engine speed, large Δ𝑢𝜁,𝑛𝑜𝑚, large gradients of 𝑢𝛼
18.11.2019Engine Systems 7
Competition
|| 18.11.2019Engine Systems 8
Controller Design
A value between
0 and 100!
Units!
||
Analyze the Bode and Nyquist diagrams of 𝐿 𝑠 = 𝐶 𝑠 ⋅ 𝑃(𝑠) Bandwidth of your controller?
Minimum return difference?
See helpful comments in the exercise instructions!
Analyze the actuator behaviours (u_ign, u_th and u_th_integr)
Discretization (c2d command, Tustin emulation)
ISCS_Ad, ISCS_Bd, ISCS_Cd, ISCS_Dd
Simulations with the nonlinear model as plant (consider the load)
18.11.2019Engine Systems 9
Controller Design
|| 18.11.2019Engine Systems 10
Implementation on Engine ECU
We have implemented a saturation for Δ𝑢𝜁 which limits Δ𝑢𝜁 ≤ 0
ISCS_Ad*u
ISCS_Dd*u
inv(ISCS_Ty)*u ISCS_Tu*u
K = ISCS_CdK = ISCS_Bd
|| 18.11.2019Engine Systems 11
Final Controller Data
Normalization matrices: ISCS_Ty, ISCS_Tu
Controller matrices: ISCS_Ad, ISCS_Bd, ISCS_Cd, ISCS_Dd (discretized
controller)
Save all these matrices in a file named controllerX.mat
(where X is an increasing integer, i.e., 1, 2, 3, …)
No other format is possible!
|| 18.11.2019Engine Systems 12
Summary
Linearize and normalize your plant model
Design a controller
Two testbench sessions for controller testing will be part of Milestone 4
(Controller testing)
Your controller(s) must be ready for the testing session at the latest.
Optional: send your controller to Hansi ([email protected]) before the testing
session, so that we can test them in simulation and give you feedback in
advance.
||
Exercise #5 was uploaded last week, complete it by November 25th
18.11.2019Engine Systems 13
Theory Exercise