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  1. /* ----------------------------------------------------------------------    
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  3. *    
  4. * $Date:        19. March 2015
  5. * $Revision:    V.1.4.5
  6. *    
  7. * Project:          CMSIS DSP Library    
  8. * Title:            arm_pid_init_f32.c    
  9. *    
  10. * Description:  Floating-point PID Control initialization function    
  11. *                                  
  12. *    
  13. * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  14. *  
  15. * Redistribution and use in source and binary forms, with or without
  16. * modification, are permitted provided that the following conditions
  17. * are met:
  18. *   - Redistributions of source code must retain the above copyright
  19. *     notice, this list of conditions and the following disclaimer.
  20. *   - Redistributions in binary form must reproduce the above copyright
  21. *     notice, this list of conditions and the following disclaimer in
  22. *     the documentation and/or other materials provided with the
  23. *     distribution.
  24. *   - Neither the name of ARM LIMITED nor the names of its contributors
  25. *     may be used to endorse or promote products derived from this
  26. *     software without specific prior written permission.
  27. *
  28. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  29. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  30. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  31. * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  32. * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  33. * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  34. * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  35. * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  36. * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  38. * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  39. * POSSIBILITY OF SUCH DAMAGE.  
  40. * ------------------------------------------------------------------- */
  41.  
  42. #include "arm_math.h"
  43.  
  44.  /**    
  45.  * @addtogroup PID    
  46.  * @{    
  47.  */
  48.  
  49. /**    
  50.  * @brief  Initialization function for the floating-point PID Control.  
  51.  * @param[in,out] *S points to an instance of the PID structure.  
  52.  * @param[in]     resetStateFlag  flag to reset the state. 0 = no change in state & 1 = reset the state.  
  53.  * @return none.  
  54.  * \par Description:  
  55.  * \par    
  56.  * The <code>resetStateFlag</code> specifies whether to set state to zero or not. \n  
  57.  * The function computes the structure fields: <code>A0</code>, <code>A1</code> <code>A2</code>    
  58.  * using the proportional gain( \c Kp), integral gain( \c Ki) and derivative gain( \c Kd)    
  59.  * also sets the state variables to all zeros.    
  60.  */
  61.  
  62. void arm_pid_init_f32(
  63.   arm_pid_instance_f32 * S,
  64.   int32_t resetStateFlag)
  65. {
  66.  
  67.   /* Derived coefficient A0 */
  68.   S->A0 = S->Kp + S->Ki + S->Kd;
  69.  
  70.   /* Derived coefficient A1 */
  71.   S->A1 = (-S->Kp) - ((float32_t) 2.0 * S->Kd);
  72.  
  73.   /* Derived coefficient A2 */
  74.   S->A2 = S->Kd;
  75.  
  76.   /* Check whether state needs reset or not */
  77.   if(resetStateFlag)
  78.   {
  79.     /* Clear the state buffer.  The size will be always 3 samples */
  80.     memset(S->state, 0, 3u * sizeof(float32_t));
  81.   }
  82.  
  83. }
  84.  
  85. /**    
  86.  * @} end of PID group    
  87.  */
  88.