/* encoder_corrector.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 "encoder_corrector.h" #include "modules/math/fixed/fixed.h" /* * The encoder corrector apply a correction factor to an encoder output to * take into account a difference in wheel size. This should be used on the * right encoder for example for a two wheeled robot. */ void encoder_corrector_init (encoder_corrector_t *corrector) { /* Default value: no correction. */ corrector->correction = 1L << 24; } void encoder_corrector_update (encoder_corrector_t *corrector, encoder_t *encoder) { /* First cancel encoder update work. */ encoder->cur -= encoder->diff; /* Update our own raw encoder position and apply factor. */ corrector->cur_raw += encoder->diff; uint16_t new = fixed_mul_f824 (corrector->cur_raw, corrector->correction); /* Now patch encoder state. */ encoder->diff = (int16_t) (new - encoder->cur); encoder->cur = new; }