arm_pid_init_f32.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        17. January 2013
00005 * $Revision:    V1.4.1
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_pid_init_f32.c    
00009 *    
00010 * Description:  Floating-point PID Control initialization function    
00011 *                  
00012 *    
00013 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00014 *  
00015 * Redistribution and use in source and binary forms, with or without 
00016 * modification, are permitted provided that the following conditions
00017 * are met:
00018 *   - Redistributions of source code must retain the above copyright
00019 *     notice, this list of conditions and the following disclaimer.
00020 *   - Redistributions in binary form must reproduce the above copyright
00021 *     notice, this list of conditions and the following disclaimer in
00022 *     the documentation and/or other materials provided with the 
00023 *     distribution.
00024 *   - Neither the name of ARM LIMITED nor the names of its contributors
00025 *     may be used to endorse or promote products derived from this
00026 *     software without specific prior written permission.
00027 *
00028 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00029 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00030 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00031 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00032 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00033 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00034 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00035 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00036 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00037 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00038 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00039 * POSSIBILITY OF SUCH DAMAGE.   
00040 * ------------------------------------------------------------------- */
00041 
00042 #include "arm_math.h"
00043 
00044  /**    
00045  * @addtogroup PID    
00046  * @{    
00047  */
00048 
00049 /**    
00050  * @brief  Initialization function for the floating-point PID Control.   
00051  * @param[in,out] *S points to an instance of the PID structure.   
00052  * @param[in]     resetStateFlag  flag to reset the state. 0 = no change in state & 1 = reset the state.   
00053  * @return none.   
00054  * \par Description:   
00055  * \par    
00056  * The <code>resetStateFlag</code> specifies whether to set state to zero or not. \n   
00057  * The function computes the structure fields: <code>A0</code>, <code>A1</code> <code>A2</code>    
00058  * using the proportional gain( \c Kp), integral gain( \c Ki) and derivative gain( \c Kd)    
00059  * also sets the state variables to all zeros.    
00060  */
00061 
00062 void arm_pid_init_f32(
00063   arm_pid_instance_f32 * S,
00064   int32_t resetStateFlag)
00065 {
00066 
00067   /* Derived coefficient A0 */
00068   S->A0 = S->Kp + S->Ki + S->Kd;
00069 
00070   /* Derived coefficient A1 */
00071   S->A1 = (-S->Kp) - ((float32_t) 2.0 * S->Kd);
00072 
00073   /* Derived coefficient A2 */
00074   S->A2 = S->Kd;
00075 
00076   /* Check whether state needs reset or not */
00077   if(resetStateFlag)
00078   {
00079     /* Clear the state buffer.  The size will be always 3 samples */
00080     memset(S->state, 0, 3u * sizeof(float32_t));
00081   }
00082 
00083 }
00084 
00085 /**    
00086  * @} end of PID group    
00087  */