aboutsummaryrefslogtreecommitdiff
path: root/src/modules/systemlib/pid
diff options
context:
space:
mode:
authorLorenz Meier <lm@inf.ethz.ch>2013-04-28 09:54:11 +0200
committerLorenz Meier <lm@inf.ethz.ch>2013-04-28 09:54:11 +0200
commit13fc6703862862f4263d8d5d085b7a16b87190e1 (patch)
tree47f3a17cb6f38b1aafe22e1cdef085cd73cd3a1d /src/modules/systemlib/pid
parentf57439b90e23de260259dec051d3e2ead2d61c8c (diff)
downloadpx4-firmware-13fc6703862862f4263d8d5d085b7a16b87190e1.tar.gz
px4-firmware-13fc6703862862f4263d8d5d085b7a16b87190e1.tar.bz2
px4-firmware-13fc6703862862f4263d8d5d085b7a16b87190e1.zip
Moved last libs, drivers and headers, cleaned up IO build
Diffstat (limited to 'src/modules/systemlib/pid')
-rw-r--r--src/modules/systemlib/pid/pid.c191
-rw-r--r--src/modules/systemlib/pid/pid.h78
2 files changed, 269 insertions, 0 deletions
diff --git a/src/modules/systemlib/pid/pid.c b/src/modules/systemlib/pid/pid.c
new file mode 100644
index 000000000..49315cdc9
--- /dev/null
+++ b/src/modules/systemlib/pid/pid.c
@@ -0,0 +1,191 @@
+/****************************************************************************
+ *
+ * Copyright (C) 2008-2012 PX4 Development Team. All rights reserved.
+ * Author: @author Laurens Mackay <mackayl@student.ethz.ch>
+ * @author Tobias Naegeli <naegelit@student.ethz.ch>
+ * @author Martin Rutschmann <rutmarti@student.ethz.ch>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ * used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file pid.c
+ * Implementation of generic PID control interface
+ */
+
+#include "pid.h"
+#include <math.h>
+
+__EXPORT void pid_init(PID_t *pid, float kp, float ki, float kd, float intmax,
+ float limit, uint8_t mode)
+{
+ pid->kp = kp;
+ pid->ki = ki;
+ pid->kd = kd;
+ pid->intmax = intmax;
+ pid->limit = limit;
+ pid->mode = mode;
+ pid->count = 0;
+ pid->saturated = 0;
+ pid->last_output = 0;
+
+ pid->sp = 0;
+ pid->error_previous = 0;
+ pid->integral = 0;
+}
+__EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float intmax, float limit)
+{
+ int ret = 0;
+
+ if (isfinite(kp)) {
+ pid->kp = kp;
+
+ } else {
+ ret = 1;
+ }
+
+ if (isfinite(ki)) {
+ pid->ki = ki;
+
+ } else {
+ ret = 1;
+ }
+
+ if (isfinite(kd)) {
+ pid->kd = kd;
+
+ } else {
+ ret = 1;
+ }
+
+ if (isfinite(intmax)) {
+ pid->intmax = intmax;
+
+ } else {
+ ret = 1;
+ }
+
+ if (isfinite(limit)) {
+ pid->limit = limit;
+
+ } else {
+ ret = 1;
+ }
+
+ return ret;
+}
+
+//void pid_set(PID_t *pid, float sp)
+//{
+// pid->sp = sp;
+// pid->error_previous = 0;
+// pid->integral = 0;
+//}
+
+/**
+ *
+ * @param pid
+ * @param val
+ * @param dt
+ * @return
+ */
+__EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, float dt)
+{
+ /* error = setpoint - actual_position
+ integral = integral + (error*dt)
+ derivative = (error - previous_error)/dt
+ output = (Kp*error) + (Ki*integral) + (Kd*derivative)
+ previous_error = error
+ wait(dt)
+ goto start
+ */
+
+ if (!isfinite(sp) || !isfinite(val) || !isfinite(val_dot) || !isfinite(dt)) {
+ return pid->last_output;
+ }
+
+ float i, d;
+ pid->sp = sp;
+
+ // Calculated current error value
+ float error = pid->sp - val;
+
+ if (isfinite(error)) { // Why is this necessary? DEW
+ pid->error_previous = error;
+ }
+
+ // Calculate or measured current error derivative
+
+ if (pid->mode == PID_MODE_DERIVATIV_CALC) {
+ d = (error - pid->error_previous) / dt;
+
+ } else if (pid->mode == PID_MODE_DERIVATIV_SET) {
+ d = -val_dot;
+
+ } else {
+ d = 0.0f;
+ }
+
+ // Calculate the error integral and check for saturation
+ i = pid->integral + (error * dt);
+
+ if (fabsf((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit ||
+ fabsf(i) > pid->intmax) {
+ i = pid->integral; // If saturated then do not update integral value
+ pid->saturated = 1;
+
+ } else {
+ if (!isfinite(i)) {
+ i = 0;
+ }
+
+ pid->integral = i;
+ pid->saturated = 0;
+ }
+
+ // Calculate the output. Limit output magnitude to pid->limit
+ float output = (pid->error_previous * pid->kp) + (i * pid->ki) + (d * pid->kd);
+
+ if (output > pid->limit) output = pid->limit;
+
+ if (output < -pid->limit) output = -pid->limit;
+
+ if (isfinite(output)) {
+ pid->last_output = output;
+ }
+
+
+ return pid->last_output;
+}
+
+
+__EXPORT void pid_reset_integral(PID_t *pid)
+{
+ pid->integral = 0;
+}
diff --git a/src/modules/systemlib/pid/pid.h b/src/modules/systemlib/pid/pid.h
new file mode 100644
index 000000000..64d668867
--- /dev/null
+++ b/src/modules/systemlib/pid/pid.h
@@ -0,0 +1,78 @@
+/****************************************************************************
+ *
+ * Copyright (C) 2008-2012 PX4 Development Team. All rights reserved.
+ * Author: @author Laurens Mackay <mackayl@student.ethz.ch>
+ * @author Tobias Naegeli <naegelit@student.ethz.ch>
+ * @author Martin Rutschmann <rutmarti@student.ethz.ch>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ * used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file pid.h
+ * Definition of generic PID control interface
+ */
+
+#ifndef PID_H_
+#define PID_H_
+
+#include <stdint.h>
+
+/* PID_MODE_DERIVATIV_CALC calculates discrete derivative from previous error
+ * val_dot in pid_calculate() will be ignored */
+#define PID_MODE_DERIVATIV_CALC 0
+/* Use PID_MODE_DERIVATIV_SET if you have the derivative already (Gyros, Kalman) */
+#define PID_MODE_DERIVATIV_SET 1
+// Use PID_MODE_DERIVATIV_NONE for a PI controller (vs PID)
+#define PID_MODE_DERIVATIV_NONE 9
+
+typedef struct {
+ float kp;
+ float ki;
+ float kd;
+ float intmax;
+ float sp;
+ float integral;
+ float error_previous;
+ float last_output;
+ float limit;
+ uint8_t mode;
+ uint8_t count;
+ uint8_t saturated;
+} PID_t;
+
+__EXPORT void pid_init(PID_t *pid, float kp, float ki, float kd, float intmax, float limit, uint8_t mode);
+__EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float intmax, float limit);
+//void pid_set(PID_t *pid, float sp);
+__EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, float dt);
+
+__EXPORT void pid_reset_integral(PID_t *pid);
+
+
+#endif /* PID_H_ */