# Desc: Calculates control variable (CV) given setpoint (SP) and
# process variable (PV). Uses proportional integral (PI)
# control.
- # Usage: update_pi arg1 arg2 arg3 arg4 arg5
- # Version: 0.0.1
+ # Usage: update_pi arg1 arg2 arg3 arg4 arg5 arg6
+ # Version: 0.1.2
# Input: arg1: path_loop_name (control loop name path)
# arg2: var_pv (process variable)
# arg3: var_sp (set point)
# arg4: tune_p (proportional tuning factor)
# arg5: tune_i (integral tuning factor)
+ # arg6: var_cv_bias (control variable bias; prevents initial jerk)
# Output: stdout: var_cv (control variable)
# file: path_var_pv
# file: path_var_sp
# file: path_tune_p
# file: path_tune_i
+ # file: path_var_cv
# file: path_sum (saves updated sum state)
# Example: update_pi /dev/shm/DC1.AC 1.0 3.0 2.0 3.0
# Depends: bc, gnu coreutils 8.30, yell(), try()
local var_sp var_pv var_cv;
local tune_p tune_i;
local term_p term_i;
- local error sum;
+ local error sum sum_cand;
local path_sum path_var_sp path_var_pv path_tune_p path_tune_i;
path_loop_name="$1";
tune_i="$5";
fi;
+ path_var_cv="$path_loop_name".cv
+
+ path_var_cv_bias="$path_loop_name".cv_bias
+ var_cv_bias="$6";
+
path_sum="$path_loop_name".sum
if [[ -f "$path_sum" ]]; then
sum="$(cat "$path_sum" | head -n1)";
#yell "DEBUG:path_loop_name:$path_loop_name";
#yell "DEBUG:var_pv:$var_pv";
#yell "DEBUG:var_sp:$var_sp";
+ #yell "DEBUG:var_cv:$var_cv";
+ #yell "DEBUG:var_cv_bias:$var_cv_bias";
#yell "DEBUG:tune_p:$tune_p";
#yell "DEBUG:tune_i:$tune_i";
error="$(try echo "$var_sp - $var_pv" | bc -l)";
#yell "DEBUG:error:$error";
- sum="$(try echo "$sum + $error" | bc -l)";
+ sum_cand="$(try echo "$sum + $error" | bc -l)";
#yell "DEBUG:sum:$sum";
+ if [[ "$(try echo "$sum_cand > 2 * $sum " | bc -l)" -eq 1 ]]; then
+ sum="$(try echo "$sum + l($error)" | bc -l)"; # dampen integral sum spikes
+ else
+ sum="$sum_cand";
+ fi;
term_p="$(try echo "$tune_p * $error" | bc -l)";
#yell "DEBUG:term_p:$term_p";
term_i="$(try echo "$tune_i * $sum" | bc -l)";
#yell "DEBUG:term_i:$term_i";
- var_cv="$(try echo "$term_p + $term_i" | bc -l)";
+ var_cv="$(try echo "$term_p + $term_i + $var_cv_bias" | bc -l)";
#yell "DEBUG:var_cv:$var_cv";
# Write variables to memory
echo "$var_pv" > "$path_var_pv";
echo "$tune_p" > "$path_tune_p";
echo "$tune_i" > "$path_tune_i";
+ echo "$var_cv" > "$path_var_cv";
+ echo "$var_cv_bias" > "$path_var_cv_bias";
# Output control variable to stdout
echo "$var_cv";
#yell "DEBUG:=============END_ROUND===============";
-}
+} # update specified PI loop
#==END function definition==
#==BEGIN Example code==
var_sp=2.0;
tune_p=1.0;
tune_i=0.1;
+var_cv_init=1000;
try rm "$path_loop_name"*
var_pv=4.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=4.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=4.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=4.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=4.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=1.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=1.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=1.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
var_pv=1.0;
-output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" | tail -n1)";
+output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
yell "DEBUG:output:$output";
#==END Example code==