From 928dc853e088849580aac368401999ea596644bb Mon Sep 17 00:00:00 2001 From: Nicolas Schodet Date: Sat, 8 Oct 2011 11:56:10 +0200 Subject: digital/avr/modules/motor: add motor control system --- digital/avr/modules/motor/pos_control/Makefile | 5 + .../avr/modules/motor/pos_control/Makefile.module | 1 + .../avr/modules/motor/pos_control/pos_control.c | 103 +++++++++++++++++++++ .../avr/modules/motor/pos_control/pos_control.h | 60 ++++++++++++ .../avr/modules/motor/pos_control/pos_control.txt | 32 +++++++ 5 files changed, 201 insertions(+) create mode 100644 digital/avr/modules/motor/pos_control/Makefile create mode 100644 digital/avr/modules/motor/pos_control/Makefile.module create mode 100644 digital/avr/modules/motor/pos_control/pos_control.c create mode 100644 digital/avr/modules/motor/pos_control/pos_control.h create mode 100644 digital/avr/modules/motor/pos_control/pos_control.txt (limited to 'digital/avr/modules/motor/pos_control') diff --git a/digital/avr/modules/motor/pos_control/Makefile b/digital/avr/modules/motor/pos_control/Makefile new file mode 100644 index 00000000..439f8adc --- /dev/null +++ b/digital/avr/modules/motor/pos_control/Makefile @@ -0,0 +1,5 @@ +BASE = ../../.. +DOC = pos_control.html +EXTRACTDOC = pos_control.h + +include $(BASE)/make/Makefile.gen diff --git a/digital/avr/modules/motor/pos_control/Makefile.module b/digital/avr/modules/motor/pos_control/Makefile.module new file mode 100644 index 00000000..cc290a21 --- /dev/null +++ b/digital/avr/modules/motor/pos_control/Makefile.module @@ -0,0 +1 @@ +motor_pos_control_SOURCES = pos_control.c diff --git a/digital/avr/modules/motor/pos_control/pos_control.c b/digital/avr/modules/motor/pos_control/pos_control.c new file mode 100644 index 00000000..80caae74 --- /dev/null +++ b/digital/avr/modules/motor/pos_control/pos_control.c @@ -0,0 +1,103 @@ +/* pos_control.c */ +/* motor - Motor control module. {{{ + * + * Copyright (C) 2011 Nicolas Schodet + * + * APBTeam: + * Web: http://apbteam.org/ + * Email: team AT apbteam DOT org + * + * 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 2 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, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * }}} */ +#include "common.h" +#include "pos_control.h" + +#include "modules/utils/utils.h" + +/** Compute a PID. + * How to compute maximum numbers size: + * Result is 24 bits (16 bits kept after shift). + * If e_sat == 1023, e max is 11 bits (do not forget the sign bit), and diff + * max is 12 bits (can be saturated with d_sat). + * If i_sat == 1023, i max is 11 bits. + * In the final addition, let's give 23 bits to the p part, and 22 bits to the + * i and d part (23b + 22b + 22b => 23b + 23b => 24b). + * Therefore, kp can be 23 - 11 = 12 bits (f4.8). + * ki can be 22 - 11 = 11 bits (f3.8). + * kd can be 22 - 12 = 10 bits (f2.8). + * How to increase this number: + * - lower the shift. + * - bound the value returned. + * - lower e, i & d saturation. */ +static inline int16_t +pos_control_compute_pid (struct pos_control_t *pos_control, int32_t e) +{ + int32_t diff, pid; + /* Saturate error. */ + UTILS_BOUND (e, -pos_control->e_sat, pos_control->e_sat); + /* Integral update. */ + pos_control->i += e; + UTILS_BOUND (pos_control->i, -pos_control->i_sat, pos_control->i_sat); + /* Differential value. */ + diff = e - pos_control->last_error; + UTILS_BOUND (diff, -pos_control->d_sat, pos_control->d_sat); + /* Compute PID. */ + pid = e * pos_control->kp + pos_control->i * pos_control->ki + + diff * pos_control->kd; + /* Save result. */ + pos_control->last_error = e; + return pid >> 8; +} + +/** Reset position control so that it does not go crazy when enabled. */ +static void +pos_control_reset (pos_control_t *pos_control) +{ + pos_control->cons = pos_control->cur; + pos_control->i = 0; + pos_control->last_error = 0; +} + +void +pos_control_init (pos_control_t *pos_control) +{ + pos_control_reset (pos_control); +} + +int16_t +pos_control_update (pos_control_t *pos_control, int16_t cur_speed, + uint8_t enabled) +{ + int32_t error; + int16_t pid; + /* Update current shaft position. */ + pos_control->cur += cur_speed; + /* Control position if enabled. */ + if (enabled) + { + /* Compute error. */ + error = pos_control->cons - pos_control->cur; + /* Compute PID. */ + pid = pos_control_compute_pid (pos_control, error); + } + else + { + pos_control_reset (pos_control); + pid = 0; + } + return pid; +} + diff --git a/digital/avr/modules/motor/pos_control/pos_control.h b/digital/avr/modules/motor/pos_control/pos_control.h new file mode 100644 index 00000000..1378f3ad --- /dev/null +++ b/digital/avr/modules/motor/pos_control/pos_control.h @@ -0,0 +1,60 @@ +#ifndef pos_control_h +#define pos_control_h +/* pos_control.h */ +/* motor - Motor control module. {{{ + * + * Copyright (C) 2011 Nicolas Schodet + * + * APBTeam: + * Web: http://apbteam.org/ + * Email: team AT apbteam DOT org + * + * 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 2 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, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * }}} */ + +/** Position control state. */ +struct pos_control_t +{ + /** Current position. */ + uint32_t cur; + /** Consign position. */ + uint32_t cons; + /** PID coefficients (f8.8, maximum depends on saturation values). */ + uint16_t kp, ki, kd; + /** Error saturation. */ + int32_t e_sat; + /** Integral saturation. */ + int32_t i_sat; + /** Differential saturation. */ + int32_t d_sat; + /** Current integral value. */ + int32_t i; + /** Last error value. */ + int32_t last_error; +}; +typedef struct pos_control_t pos_control_t; + +/** Initialise position control. */ +void +pos_control_init (pos_control_t *pos_control); + +/** Control position of system, take current speed as input, return the new + * command. */ +int16_t +pos_control_update (pos_control_t *pos_control, int16_t cur_speed, + uint8_t enabled); + +#endif /* pos_control_h */ diff --git a/digital/avr/modules/motor/pos_control/pos_control.txt b/digital/avr/modules/motor/pos_control/pos_control.txt new file mode 100644 index 00000000..d1c1d03f --- /dev/null +++ b/digital/avr/modules/motor/pos_control/pos_control.txt @@ -0,0 +1,32 @@ +========================== + motor/pos_control module +========================== +:Author: Nicolas Schodet + +Introduction +============ + +This module provides position control, usually for a DC motor. Given a +position consign, it will adjust output power so that the measured position +matches the consign. There is no speed control, this is handled by another +module. + +Usage +===== + +The `pos_control_t` structure contains both current control state and control +parameters. The `kp`, `kd` and `ki` parameters are the PID coefficients, +using a fixed point representation. The `e_sat`, `i_sat` and `d_sat` are the +maximum values for error, integral and differential values. They must be +adapted so that PID computation does not overflow. See the +`pos_control_compute_pid` function comments for guidelines to choose those +values. + +The `cur` field is updated by this module with the current position. The +`cons` field must be written by user to set the position consign. This module +will try to make the current position matches the consign position. + +API +=== + +.. include:: pos_control.exd -- cgit v1.2.3