Adam Smith's The Invisible Hand: The Feedback Structure of Markets. From Sterman JD Business Dynamics p170 Fig 5-26. A price-mediated resource allocation system..
Double loop version of IM-8908 Based on 1990 SDR Article. Control systems act to make their own input match internal standards or reference signals. Competent control systems create illusions of stimulus response causality. Stimulus-response theory can approximate the relationship between disturbance and action, but it can't predict the consequences of behavior. These consequences are maintained despite disturbances. See also Double loop learning and Nurse Thinking Insights. See also IM-9273 for DLL LAIR model
Double loop version of IM-8908 Based on 1990 SDR Article. Control systems act to make their own input match internal standards or reference signals. Competent control systems create illusions of stimulus response causality. Stimulus-response theory can approximate the relationship between disturbance and action, but it can't predict the consequences of behavior. These consequences are maintained despite disturbances. See also Double loop learning and Nurse Thinking Insights. See also IM-9273 for DLL LAIR model
A simple model of a PID controller, controlling a valve refilling a leaky water tank.
In the scenario, at T=10 minutes, a faucet is opened for one minute, draining the tank. There's also a constant amount of leakage from the tank at all times.
The best way to play with the PID controller parameters is to click "Simulate", then click on the "map pin"-shaped icon on the simulation results, which will link the graphs to the model. Without closing the graphs, one can now drag the parameter sliders and see the graphs change.
Based on Emery Roe (2023) When Complex is as Simple as it Gets: Guide for Recasting Policy and Management in the Anthropocene, IDS Working Paper 589, Brighton: Institute of Development Studies and blog
