unitproc/bkt-updateLoopPI

   1 #!/bin/bash
   2
   3 #==BEGIN function definition==
   4 yell() { echo "$0: $*" >&2; } # print script path and all args to stderr
   5 die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status
   6 try() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails
   7 update_pi() {
   8     # Desc: Calculates control variable (CV) given setpoint (SP) and
   9     #   process variable (PV). Uses proportional integral (PI)
  10     #   control.
  11     # Usage: update_pi arg1 arg2 arg3 arg4 arg5 arg6
  12     # Version: 0.1.3
  13     # Input: arg1: path_loop_name (control loop name path)
  14     #        arg2: var_pv (process variable)
  15     #        arg3: var_sp (set point)
  16     #        arg4: tune_p (proportional tuning factor)
  17     #        arg5: tune_i (integral tuning factor)
  18     #        arg6: var_cv_bias (control variable bias; prevents initial jerk)
  19     # Output: stdout: var_cv (control variable)
  20     #         file: path_var_pv
  21     #         file: path_var_sp
  22     #         file: path_tune_p
  23     #         file: path_tune_i
  24     #         file: path_var_cv
  25     #         file: path_sum (saves updated sum state)
  26     # Example: update_pi /dev/shm/DC1.AC 1.0 3.0 2.0 3.0
  27     # Depends: bc, gnu coreutils 8.30, yell(), try()
  28     local var_sp var_pv var_cv;
  29     local tune_p tune_i;
  30     local term_p term_i;
  31     local error sum sum_cand;
  32     local path_sum path_var_sp path_var_pv path_tune_p path_tune_i;
  33
  34     path_loop_name="$1";
  35
  36     path_var_pv="$path_loop_name".pv
  37     var_pv="$2"; # read provided process variable
  38
  39     path_var_sp="$path_loop_name".sp
  40     if [[ -f "$path_var_sp" ]]; then
  41         var_sp="$(cat "$path_var_sp" | head -n1)";
  42     else
  43         var_sp="$3";
  44     fi;
  45
  46     path_tune_p="$path_loop_name".tune_p
  47     if [[ -f "$path_tune_p" ]]; then
  48         tune_p="$(cat "$path_tune_p" | head -n1)";
  49     else
  50         tune_p="$4";
  51     fi;
  52
  53     path_tune_i="$path_loop_name".tune_i
  54     if [[ -f "$path_tune_i" ]]; then
  55         tune_i="$(cat "$path_tune_i" | head -n1)";
  56     else
  57         tune_i="$5";
  58     fi;
  59
  60     path_var_cv="$path_loop_name".cv
  61
  62     path_var_cv_bias="$path_loop_name".cv_bias
  63     var_cv_bias="$6";
  64
  65     path_sum="$path_loop_name".sum
  66     if [[ -f "$path_sum" ]]; then
  67         sum="$(cat "$path_sum" | head -n1)";
  68     else
  69         sum=0;
  70     fi;
  71
  72     #yell "DEBUG:path_loop_name:$path_loop_name";
  73     #yell "DEBUG:var_pv:$var_pv";
  74     #yell "DEBUG:var_sp:$var_sp";
  75     #yell "DEBUG:var_cv:$var_cv";
  76     #yell "DEBUG:var_cv_bias:$var_cv_bias";
  77     #yell "DEBUG:tune_p:$tune_p";
  78     #yell "DEBUG:tune_i:$tune_i";
  79
  80     error="$(try echo "$var_sp - $var_pv" | bc -l)";
  81     #yell "DEBUG:error:$error";
  82     sum_cand="$(try echo "$sum + $error" | bc -l)";
  83     #yell "DEBUG:sum:$sum";
  84     if [[ "$(try echo "$sum_cand > 2 * $sum " | bc -l)" -eq 1 ]]; then
  85         sum="$(try echo "$sum + l($error + 1)" | bc -l)"; # dampen integral sum spikes
  86     else
  87         sum="$sum_cand";
  88     fi;
  89     term_p="$(try echo "$tune_p * $error" | bc -l)";
  90     #yell "DEBUG:term_p:$term_p";
  91     term_i="$(try echo "$tune_i * $sum" | bc -l)";
  92     #yell "DEBUG:term_i:$term_i";
  93     var_cv="$(try echo "$term_p + $term_i + $var_cv_bias" | bc -l)";
  94     #yell "DEBUG:var_cv:$var_cv";
  95
  96     # Write variables to memory
  97     echo "$sum" > "$path_sum";
  98     echo "$var_sp" > "$path_var_sp";
  99     echo "$var_pv" > "$path_var_pv";
 100     echo "$tune_p" > "$path_tune_p";
 101     echo "$tune_i" > "$path_tune_i";
 102     echo "$var_cv" > "$path_var_cv";
 103     echo "$var_cv_bias" > "$path_var_cv_bias";
 104
 105     # Output control variable to stdout
 106     echo "$var_cv";
 107
 108     #yell "DEBUG:=============END_ROUND===============";
 109 } # update specified PI loop
 110 #==END function definition==
 111
 112 #==BEGIN Example code==
 113 path_loop_name="/tmp/DC1.AC";
 114 var_pv=1.0;
 115 var_sp=2.0;
 116 tune_p=1.0;
 117 tune_i=0.1;
 118 var_cv_init=1000;
 119 try rm "$path_loop_name"*
 120
 121 var_pv=4.0;
 122 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 123 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 124 yell "DEBUG:output:$output";
 125 var_pv=4.0;
 126 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 127 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 128 yell "DEBUG:output:$output";
 129 var_pv=4.0;
 130 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 131 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 132 yell "DEBUG:output:$output";
 133 var_pv=4.0;
 134 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 135 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 136 yell "DEBUG:output:$output";
 137 var_pv=4.0;
 138 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 139 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 140 yell "DEBUG:output:$output";
 141 var_pv=1.0;
 142 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 143 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 144 yell "DEBUG:output:$output";
 145 var_pv=1.0;
 146 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 147 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 148 yell "DEBUG:output:$output";
 149 var_pv=1.0;
 150 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 151 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 152 yell "DEBUG:output:$output";
 153 var_pv=1.0;
 154 output="$(update_pi "$path_loop_name" "$var_pv" "$var_sp" "$tune_p" "$tune_i" "$var_cv_init" | tail -n1)";
 155 yell "DEBUG:sum:$(cat "$path_loop_name".sum | head -n1)";
 156 yell "DEBUG:output:$output";
 157 #==END Example code==
 158
 159 # Author: Steven Baltakatei Sandoval
 160 # License: GPLv3+