What about this design? 1. Take a "dumb" open loop controller. f(t). 2. Take a "smart" closed loop controller that reads glucose levels, f(t) and outputs g(t)

What about this design? 1. Take a "dumb" open loop controller. f(t). 2. Take a "smart" closed loop controller that reads glucose levels, f(t) and outputs g(t), a correction term. 3. Clamp the correction to a safe range to get h(t) 4. Output f(t) + h(t) If the closed loop controller crashes, the output is f(t). If the closed loop controller goes haywire, the output will be safe.