A PID algorithm library based on Temper for mruby.
Mruby uses mrbgems, which adds gems into the compilation process. Add the following to your
build_config.rb in the mruby source directory:
config.gem :github => 'cadwallion/mruby-pid'
./minirake in the mruby source directory and mruby-pid will be added.
A PID controller is based on four values:
- kp - Proportional Tuning Parameter
- ki - Integral Tuning Parameter
- kd - Derivative Tuning Parameter
- setpoint - target temperature
PID class can either be initialized with the kp/ki/kd values, or tuned after initialization
pid1 = PID.new :kp => 1.0, :ki => 1.0, :kd => 1.0 pid1.setpoint = 200.0 # Target temperature in Fahrenheit pid2 = PID.new pid2.tune 1.0, 1.0, 1.0 pid2.setpoint = 200.0 # Target temperature in Fahrenheit
Once created, the heart of the PID library is in the
PID#control method. Pass this method the
current temperature, and it will use the modified PID algorithm to output a power level. Use
this value to adjust your heating/cooling control based on the power.
pid = PID.new :kp => 1.0, :ki => 1.0, :kd => 1.0 pid.setpoint = 185.5 power_level = pid.control 95.0
For some systems, there is an upperbound to PWM control values (for example, the Arduino PWM
values cannot exceed 255). The PID's minimum and maximum can be set with the
:minimum options at initialization.
See the examples directory for common applications of the mruby-pid library.