From bc38b408c53281ee985f6f9d67accc5733d99e37 Mon Sep 17 00:00:00 2001 From: Nicolas Schodet Date: Mon, 28 Jan 2008 21:12:12 +0100 Subject: * digital/asserv/src/asserv: - imported old sources. - removed holes support (rule 2006). --- digital/asserv/src/asserv/pos.c | 144 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 digital/asserv/src/asserv/pos.c (limited to 'digital/asserv/src/asserv/pos.c') diff --git a/digital/asserv/src/asserv/pos.c b/digital/asserv/src/asserv/pos.c new file mode 100644 index 00000000..eecd71f3 --- /dev/null +++ b/digital/asserv/src/asserv/pos.c @@ -0,0 +1,144 @@ +/* pos.c - Position motor control. */ +/* asserv - Position & speed motor control on AVR. {{{ + * + * Copyright (C) 2005 Nicolas Schodet + * + * Robot APB Team/Efrei 2006. + * Web: http://assos.efrei.fr/robot/ + * Email: robot AT efrei DOT fr + * + * 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. + * + * }}} */ + +/** + * This file is responsible for position motor control. The consign is a + * position of the motor shafts, as theta/alpha. Theta is the sum of right + * and left position, alpha is the difference between the right and the left + * position. + * 16 bits are enough as long as there is no long blocking (see 2005 cup!). + */ + +/** Current theta/alpha. */ +uint32_t pos_theta_cur, pos_alpha_cur; +/** Consign theta/alpha. */ +uint32_t pos_theta_cons, pos_alpha_cons; + +/** Error saturation. */ +int32_t pos_e_sat = 1023; +/** Integral saturation. */ +int32_t pos_int_sat = 1023; +/** P coefficients. */ +uint16_t pos_theta_kp, pos_alpha_kp; +/** I coefficients. */ +uint16_t pos_theta_ki, pos_alpha_ki; +/** D coefficients. */ +uint16_t pos_theta_kd, pos_alpha_kd; +/** Blocked value. If error is greater than this value, stop the robot and + * report blocked state. */ +int32_t pos_blocked = 15000L; + +/** Current integral values. */ +int32_t pos_theta_int, pos_alpha_int; +/** Last error values. */ +int32_t pos_theta_e_old, pos_alpha_e_old; +/** One if blocked. */ +uint8_t pos_blocked_state; + +/* +AutoDec */ +/* -AutoDec */ + +/** 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. + * If int_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 & int saturation. */ +static inline int16_t +pos_compute_pid (int32_t e, int32_t *i, int32_t *e_old, + uint16_t kp, uint16_t ki, uint16_t kd) +{ + int32_t diff, pid; + /* Saturate error. */ + UTILS_BOUND (e, -pos_e_sat, pos_e_sat); + /* Integral update. */ + *i += e; + UTILS_BOUND (*i, -pos_int_sat, pos_int_sat); + /* Differential value. */ + diff = e - *e_old; + /* Compute PID. */ + pid = e * kp + *i * ki + diff * kd; + /* Save result. */ + *e_old = e; + return pid >> 8; +} + +/** Update PWM according to consign. */ +static void +pos_update (void) +{ + int16_t pid_theta, pid_alpha; + int32_t diff_theta, diff_alpha; + /* Update current shaft positions. */ + pos_theta_cur += counter_left_diff + counter_right_diff; + pos_alpha_cur += counter_right_diff - counter_left_diff; + /* Compute PID. */ + diff_theta = pos_theta_cons - pos_theta_cur; + diff_alpha = pos_alpha_cons - pos_alpha_cur; + if (pos_blocked_state + || diff_theta < -pos_blocked || pos_blocked < diff_theta + || diff_alpha < -pos_blocked || pos_blocked < diff_alpha) + { + /* Blocked. */ + pwm_left = 0; + pwm_right = 0; + pos_blocked_state = 1; + main_sequence_finish = main_sequence | 0x80; + } + else + { + pid_theta = pos_compute_pid (diff_theta, &pos_theta_int, + &pos_theta_e_old, pos_theta_kp, + pos_theta_ki, pos_theta_kd); + pid_alpha = pos_compute_pid (diff_alpha, &pos_alpha_int, + &pos_alpha_e_old, pos_alpha_kp, + pos_alpha_ki, pos_alpha_kd); + /* Update PWM. */ + pwm_left = pid_theta - pid_alpha; + UTILS_BOUND (pwm_left, -PWM_MAX, PWM_MAX); + pwm_right = pid_theta + pid_alpha; + UTILS_BOUND (pwm_right, -PWM_MAX, PWM_MAX); + } +} + +/** Reset position control internal state. */ +static void +pos_reset (void) +{ + pos_theta_int = pos_alpha_int = 0; + pos_theta_cur = pos_alpha_cur = 0; + pos_theta_cons = pos_alpha_cons = 0; + pos_theta_e_old = pos_alpha_e_old = 0; + pos_blocked_state = 0; +} -- cgit v1.2.3