Move the library to the separate repository

PID_test/PID.c

@@ -0,0 +1,64 @@
+/*
+ * This file is part of the moving_model project.
+ * Copyright 2025 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <strings.h>
+#include <usefull_macros.h>
+
+#include "PID.h"
+
+PIDController_t *pid_create(PIDpar_t *gain, size_t Iarrsz){
+    if(!gain || Iarrsz < 3) return NULL;
+    PIDController_t *pid = (PIDController_t*)calloc(1, sizeof(PIDController_t));
+    pid->gain = *gain;
+    pid->pidIarrSize = Iarrsz;
+    pid->pidIarray = (double*)calloc(Iarrsz, sizeof(double));
+    return pid;
+}
+
+void pid_clear(PIDController_t *pid){
+    if(!pid) return;
+    DBG("CLEAR PID PARAMETERS");
+    bzero(pid->pidIarray, sizeof(double) * pid->pidIarrSize);
+    pid->integral = 0.;
+    pid->prev_error = 0.;
+    pid->curIidx = 0;
+}
+
+void pid_delete(PIDController_t **pid){
+    if(!pid || !*pid) return;
+    if((*pid)->pidIarray) free((*pid)->pidIarray);
+    free(*pid);
+    *pid = NULL;
+}
+
+double pid_calculate(PIDController_t *pid, double error, double dt){
+    // calculate flowing integral
+    double oldi = pid->pidIarray[pid->curIidx], newi = error * dt;
+    DBG("oldi/new: %g, %g", oldi, newi);
+    pid->pidIarray[pid->curIidx++] = newi;
+    if(pid->curIidx >= pid->pidIarrSize) pid->curIidx = 0;
+    pid->integral += newi - oldi;
+    double derivative = (error - pid->prev_error) / dt;
+    pid->prev_error = error;
+    double sum = pid->gain.P * error + pid->gain.I * pid->integral + pid->gain.D * derivative;
+    DBG("P=%g, I=%g, D=%g; sum=%g", pid->gain.P * error, pid->gain.I * pid->integral, pid->gain.D * derivative, sum);
+    return sum;
+}