/* speed.c - PI speed control. */ /* asserv - Position & speed motor control on a ATmega128. {{{ * * Copyright (C) 2004 Nicolas Schodet * * Robot APB Team/Efrei 2005. * 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. * * }}} */ #include "linesensor.c" /** Maximum value the pwm can reach (defined by the avr configuration) */ #define PWM_MAX 255 /** Maximum value for the pwm in linefol mode (controls avg speed) */ int16_t linefol_max_pwm = 80; /** Table and index for calculating the derivate term */ #define N_LINEPOS_DER_TAB 8 // max : 256 int16_t linepos_der_tab[N_LINEPOS_DER_TAB]; uint8_t linepos_der_index; /** Attenuation for filtering the derivate term */ #define K_ATT_LINEPOS_DER 0.95 /** Actual speed. */ int8_t speed_left, speed_right; /** Wanted speed. */ int8_t speed_left_aim, speed_right_aim; /** Acceleration value. */ uint8_t speed_acc = 8; /** Acceleration counter, speed gets updated when it reachs 0. */ uint8_t speed_acc_cpt; /** Integral term. */ int16_t speed_left_int, speed_right_int; /** Integral max value. */ int16_t speed_int_max = 1024; /** Last error value. */ int16_t speed_left_e_old, speed_right_e_old; /** P coeficients. 5.8 fixed point format. */ uint16_t speed_kp = 2 * 255; /** I coeficients. 4.8 fixed point format. */ uint16_t speed_ki = 1 * 255; /** D coeficient. 4.8 fixed point format. */ uint16_t speed_kd = 1 * 255; /* +AutoDec */ /** Initialise speed parameters. */ static inline void speed_init (void); /** Update speeds according to the wanted speeds and the acceleration. */ static inline void speed_update (void); /** Compute new pwm value for left motor. */ static inline void speed_compute_left_pwm (void); /** Compute new pwm value for right motor. */ static inline void speed_compute_right_pwm (void); /** Forget past event, usefull when the speed control is disabled for some * time. */ static inline void speed_restart (void); /* -AutoDec */ /** Initialise speed parameters. */ static inline void speed_init (void) { speed_acc = 8; speed_int_max = 1024; speed_kp = 2 * 255; speed_ki = 1 * 255; } /** Update speeds according to the wanted speeds and the acceleration. */ static inline void speed_update (void) { if (speed_acc) { speed_acc_cpt--; if (speed_acc_cpt == 0) { speed_acc_cpt = speed_acc; /* Update speeds. */ if (speed_left > speed_left_aim) speed_left--; else if (speed_left < speed_left_aim) speed_left++; if (speed_right > speed_right_aim) speed_right--; else if (speed_right < speed_right_aim) speed_right++; } } else { speed_left = speed_left_aim; speed_right = speed_right_aim; } } /** Compute new pwm value for motors in linefol mode. */ static inline void speed_compute_linefol_pwm (void) { int16_t e,speed_linepos_der; uint8_t i; int16_t pwm; // reusing left channel variables e = linepos; /* 10b = 8b + 9b */ /* Derivative update. */ i=linepos_der_index; // old index linepos_der_index= // updating index by (linepos_der_index+N_LINEPOS_DER_TAB-1) // modulo adressing & (N_LINEPOS_DER_TAB-1); linepos_der_tab[linepos_der_index] = // last der value (linepos_der_tab[i] + e - speed_left_e_old) * K_ATT_LINEPOS_DER; speed_linepos_der = 0; for(i=0 ; i < N_LINEPOS_DER_TAB ; i++) // calculating sum speed_linepos_der += linepos_der_tab[i]; /* Integral update (reusing left channel variables). */ speed_left_int += e; /* 12b = 11b + 10b */ if (speed_left_int > speed_int_max) /* 11b */ speed_left_int = speed_int_max; else if (speed_left_int < -speed_int_max) speed_left_int = -speed_int_max; /* Compute PI. */ /* 16b = 15b + 15b */ pwm = dsp_mul_i16f88 (e, speed_kp) /* 15b = 10b * 5.8b */ + dsp_mul_i16f88 (speed_left_int, speed_ki) /* 15b = 11b * 4.8b */ + dsp_mul_i16f88 (speed_linepos_der, speed_kd); /* 15b = 11b * 4.8b */ /* Save result. */ speed_left_e_old = e; if(pwm > 0) { pwm_left = linefol_max_pwm * (PWM_MAX - pwm); pwm_right = linefol_max_pwm * (PWM_MAX); } else { pwm_left = linefol_max_pwm * PWM_MAX; pwm_right = linefol_max_pwm * (PWM_MAX - pwm); } } /** Compute new pwm value for left motor. */ static inline void speed_compute_left_pwm (void) { int16_t e; int16_t pwm; e = speed_left - counter_left_diff; /* 10b = 8b + 9b */ /* Integral update. */ speed_left_int += e; /* 12b = 11b + 10b */ if (speed_left_int > speed_int_max) /* 11b */ speed_left_int = speed_int_max; else if (speed_left_int < -speed_int_max) speed_left_int = -speed_int_max; /* Compute PI. */ /* 16b = 15b + 15b */ pwm = dsp_mul_i16f88 (e, speed_kp) /* 15b = 10b * 5.8b */ + dsp_mul_i16f88 (speed_left_int, speed_ki); /* 15b = 11b * 4.8b */ /* Save result. */ speed_left_e_old = e; pwm_left = pwm; } /** Compute new pwm value for right motor. */ static inline void speed_compute_right_pwm (void) { int16_t e; int16_t pwm; e = speed_right - counter_right_diff; /* Integral update. */ speed_right_int += e; if (speed_right_int > speed_int_max) speed_right_int = speed_int_max; else if (speed_right_int < -speed_int_max) speed_right_int = -speed_int_max; /* Compute PI. */ pwm = dsp_mul_i16f88 (e, speed_kp) + dsp_mul_i16f88 (speed_right_int, speed_ki); /* Save result. */ speed_right_e_old = e; pwm_right = pwm; } /** Forget past event, usefull when the speed control is disabled for some * time. */ static inline void speed_restart (void) { speed_left_int = 0; speed_right_int = 0; speed_left = 0; speed_right = 0; }