1 /***************************************************************************
5 ----------------------------------------------------------------------------
7 FUNCTION: Trims the simulated aircraft by using certain
8 controls to null out a similar number of outputs.
10 This routine used modified Newton-Raphson method to find the vector
11 of control corrections, delta_U, to drive a similar-sized vector of
12 output errors, Y, to near-zero. Nearness to zero is to within a
13 tolerance specified by the Criteria vector. An optional Weight
14 vector can be used to improve the numerical properties of the
15 Jacobian matrix (called H_Partials).
17 Using a single-sided difference method, each control is
18 independently perturbed and the change in each output of
19 interest is calculated, forming a Jacobian matrix H (variable
25 The columns of H correspond to the control effect; the rows of
26 H correspond to the outputs affected.
28 We wish to find dU such that for U = U0 + dU,
33 One solution is dU = inv(H)*(-Y0); however, inverting H
34 directly is not numerically sound, since it may be singular
35 (especially if one of the controls is on a limit, or the
36 problem is poorly posed). An alternative is to either weight
37 the elements of dU to make them more normalized; another is to
38 multiply both sides by the transpose of H and invert the
39 resulting [H' H]. This routine does both:
42 W (-Y0) = W H dU premultiply by W
43 H' W (-Y0) = H' W H dU premultiply by H'
45 dU = [inv(H' W H)][ H' W (-Y0)] Solve for dU
47 As a further refinement, dU is limited to a smallish magnitude
48 so that Y approaches 0 in small steps (to avoid an overshoot
49 if the problem is inherently non-linear).
51 Lastly, this routine can be easily fooled by "local minima",
52 or depressions in the solution space that don't lead to a Y =
53 0 solution. The only advice we can offer is to "go somewheres
54 else and try again"; often approaching a trim solution from a
55 different (non-trimmed) starting point will prove beneficial.
58 ----------------------------------------------------------------------------
60 MODULE STATUS: developmental
62 ----------------------------------------------------------------------------
64 GENEALOGY: Created from old CASTLE SHELL$TRIM.PAS
65 on 6 FEB 95, which was based upon an Ames
66 CASPRE routine called BQUIET.
68 ----------------------------------------------------------------------------
70 DESIGNED BY: E. B. Jackson
76 ----------------------------------------------------------------------------
82 950307 Modified to make use of ls_get_sym_val and ls_put_sym_val
84 950329 Fixed bug in making use of more than 3 controls;
85 removed call by ls_trim_get_set() to ls_trim_init(). EBJ
91 Revision 1.1 1999/06/17 18:07:33 curt
94 Revision 1.1.1.1 1999/04/05 21:32:45 curt
95 Start of 0.6.x branch.
97 * Revision 1.9 1995/03/29 16:09:56 bjax
98 * Fixed bug in having more than three trim controls; removed unnecessary
99 * call to ls_trim_init in ls_trim_get_set. EBJ
101 * Revision 1.8 1995/03/16 12:28:40 bjax
102 * Fixed problem where ls_trim() returns non-zero if
103 * symbols are not loaded - implies vehicle trimmed when
104 * actually no trim attempt is made. This results in storing of non-
105 * trimmed initial conditions in sims without defined trim controls.
107 * Revision 1.7 1995/03/15 12:17:12 bjax
108 * Added flag marker line to ls_trim_put_set() routine output.
110 * Revision 1.6 1995/03/08 11:49:07 bjax
111 * Minor improvements to ls_trim_get_set; deleted weighting parameter
112 * for output definition; added comment lines to settings file output.
114 * Revision 1.5 1995/03/07 22:38:04 bjax
115 * Removed ls_generic.h; this version relies entirely on symbol table routines to
116 * set and get variable values. Added additional fields to Control record structure;
117 * created Output record with appropriate fields. Added ls_trim_put_set() and
118 * ls_trim_get_set() routines. Heavily modified initialization routine; most of this
119 * logic now resides in ls_trim_get_set(). Renamed all routines so that they being
120 * with "ls_trim_" to avoid conflicts.
123 * Revision 1.4 1995/03/07 13:04:16 bjax
124 * Configured to use ls_get_sym_val() and ls_set_sym_val().
126 * Revision 1.3 1995/03/03 01:59:53 bjax
127 * Moved definition of SYMBOL_NAME and SYMBOL_TYPE to ls_sym.h
128 * and removed from this module. EBJ
130 * Revision 1.2 1995/02/27 19:53:41 bjax
131 * Moved symbol routines to ls_sym.c to declutter this file. EBJ
133 * Revision 1.1 1995/02/27 18:14:10 bjax
137 ----------------------------------------------------------------------------
141 ----------------------------------------------------------------------------
145 ----------------------------------------------------------------------------
149 ----------------------------------------------------------------------------
153 ----------------------------------------------------------------------------
157 --------------------------------------------------------------------------*/
159 static char rcsid[] = "$Id$";
166 #include "ls_constants.h"
167 #include "ls_types.h"
169 #include "ls_matrix.h"
170 #include "ls_interface.h"
178 #define MAX_NUMBER_OF_CONTROLS 10
179 #define MAX_NUMBER_OF_OUTPUTS 10
180 #define STEP_LIMIT 0.01
181 #define NIL_POINTER 0L
183 #define FACILITY_NAME_STRING "trim"
184 #define CURRENT_VERSION 10
190 double Min_Val, Max_Val, Curr_Val, Authority;
191 double Percent, Requested_Percent, Pert_Size;
192 int Ineffective, At_Limit;
198 double Curr_Val, Weighting, Trim_Criteria;
203 static int Symbols_loaded = 0;
205 static int Trim_Cycles;
210 static int Number_of_Controls;
211 static int Number_of_Outputs;
212 static control_rec Controls[ MAX_NUMBER_OF_CONTROLS ];
213 static output_rec Outputs[ MAX_NUMBER_OF_OUTPUTS ];
215 static double **H_Partials;
217 static double Baseline_Output[ MAX_NUMBER_OF_OUTPUTS ];
218 static double Saved_Control, Saved_Control_Percent;
220 static double Cost, Previous_Cost;
226 /* Initialize partials matrix */
238 for (i=0;i<Number_of_Controls;i++)
240 Controls[i].Curr_Val = ls_get_sym_val( &Controls[i].Symbol, &error );
241 if (error) Controls[i].Symbol.Addr = NIL_POINTER;
242 Controls[i].Requested_Percent =
243 (Controls[i].Curr_Val - Controls[i].Min_Val)
244 /Controls[i].Authority;
247 H_Partials = nr_matrix( 1, Number_of_Controls, 1, Number_of_Controls );
248 if (H_Partials == 0) return -1;
253 void ls_trim_get_vals()
254 /* Load the Output vector, and calculate control percent used */
258 for (i=0;i<Number_of_Outputs;i++)
260 Outputs[i].Curr_Val = ls_get_sym_val( &Outputs[i].Symbol, &error );
261 if (error) Outputs[i].Symbol.Addr = NIL_POINTER;
265 for (i=0;i<Number_of_Controls;i++)
267 Controls[i].Curr_Val = ls_get_sym_val( &Controls[i].Symbol, &error );
268 if (error) Controls[i].Symbol.Addr = NIL_POINTER;
269 Controls[i].Percent =
270 (Controls[i].Curr_Val - Controls[i].Min_Val)
271 /Controls[i].Authority;
277 void ls_trim_move_controls()
278 /* This routine moves the current control to specified percent of authority */
282 for(i=0;i<Number_of_Controls;i++)
284 Controls[i].At_Limit = 0;
285 if (Controls[i].Requested_Percent <= 0.0)
287 Controls[i].Requested_Percent = 0.0;
288 Controls[i].At_Limit = 1;
290 if (Controls[i].Requested_Percent >= 1.0)
292 Controls[i].Requested_Percent = 1.0;
293 Controls[i].At_Limit = 1;
295 Controls[i].Curr_Val = Controls[i].Min_Val +
296 (Controls[i].Max_Val - Controls[i].Min_Val) *
297 Controls[i].Requested_Percent;
301 void ls_trim_put_controls()
302 /* Put current control requests out to controls themselves */
306 for (i=0;i<Number_of_Controls;i++)
307 if (Controls[i].Symbol.Addr)
308 ls_set_sym_val( &Controls[i].Symbol, Controls[i].Curr_Val );
311 void ls_trim_calc_cost()
312 /* This routine calculates the current distance, or cost, from trim */
317 for(i=0;i<Number_of_Outputs;i++)
318 Cost += pow((Outputs[i].Curr_Val/Outputs[i].Trim_Criteria),2.0);
321 void ls_trim_save_baseline_outputs()
325 for (i=0;i<Number_of_Outputs;i++)
326 Baseline_Output[i] = ls_get_sym_val( &Outputs[i].Symbol, &error );
329 int ls_trim_eval_outputs()
334 for(i=0;i<Number_of_Outputs;i++)
335 if( fabs(Outputs[i].Curr_Val) > Outputs[i].Trim_Criteria) trimmed = 0;
339 void ls_trim_calc_h_column()
342 double delta_control, delta_output;
344 delta_control = (Controls[Index].Curr_Val - Saved_Control)/Controls[Index].Authority;
346 for(i=0;i<Number_of_Outputs;i++)
348 delta_output = Outputs[i].Curr_Val - Baseline_Output[i];
349 H_Partials[i+1][Index+1] = delta_output/delta_control;
353 void ls_trim_do_step()
355 int i, j, l, singular;
356 double **h_trans_w_h;
357 double delta_req_mag, scaling;
358 double delta_U_requested[ MAX_NUMBER_OF_CONTROLS ];
359 double temp[ MAX_NUMBER_OF_CONTROLS ];
361 /* Identify ineffective controls (whose partials are all near zero) */
363 for (j=0;j<Number_of_Controls;j++)
365 Controls[j].Ineffective = 1;
366 for(i=0;i<Number_of_Outputs;i++)
367 if (fabs(H_Partials[i+1][j+1]) > EPS) Controls[j].Ineffective = 0;
370 /* Identify uncontrollable outputs */
372 for (j=0;j<Number_of_Outputs;j++)
374 Outputs[j].Uncontrollable = 1;
375 for(i=0;i<Number_of_Controls;i++)
376 if (fabs(H_Partials[j+1][i+1]) > EPS) Outputs[j].Uncontrollable = 0;
379 /* Calculate well-conditioned partials matrix [ H' W H ] */
381 h_trans_w_h = nr_matrix(1, Number_of_Controls, 1, Number_of_Controls);
382 if (h_trans_w_h == 0)
384 fprintf(stderr, "Memory error in ls_trim().\n");
387 for (l=1;l<=Number_of_Controls;l++)
388 for (j=1;j<=Number_of_Controls;j++)
390 h_trans_w_h[l][j] = 0.0;
391 for (i=1;i<=Number_of_Outputs;i++)
393 H_Partials[i][l]*H_Partials[i][j]*Outputs[i-1].Weighting;
396 /* Invert the partials array [ inv( H' W H ) ]; note: h_trans_w_h is replaced
397 with its inverse during this function call */
399 singular = nr_gaussj( h_trans_w_h, Number_of_Controls, 0, 0 );
401 if (singular) /* Can't invert successfully */
403 nr_free_matrix( h_trans_w_h, 1, Number_of_Controls,
404 1, Number_of_Controls );
405 fprintf(stderr, "Singular matrix in ls_trim().\n");
409 /* Form right hand side of equality: temp = [ H' W (-Y) ] */
411 for(i=0;i<Number_of_Controls;i++)
414 for(j=0;j<Number_of_Outputs;j++)
415 temp[i] -= H_Partials[j+1][i+1]*Baseline_Output[j]*Outputs[j].Weighting;
418 /* Solve for dU = [inv( H' W H )][ H' W (-Y)] */
419 for(i=0;i<Number_of_Controls;i++)
421 delta_U_requested[i] = 0.0;
422 for(j=0;j<Number_of_Controls;j++)
423 delta_U_requested[i] += h_trans_w_h[i+1][j+1]*temp[j];
426 /* limit step magnitude to certain size, but not direction */
429 for(i=0;i<Number_of_Controls;i++)
430 delta_req_mag += delta_U_requested[i]*delta_U_requested[i];
431 delta_req_mag = sqrt(delta_req_mag);
432 scaling = STEP_LIMIT/delta_req_mag;
434 for(i=0;i<Number_of_Controls;i++)
435 delta_U_requested[i] *= scaling;
437 /* Convert deltas to percent of authority */
439 for(i=0;i<Number_of_Controls;i++)
440 Controls[i].Requested_Percent = Controls[i].Percent + delta_U_requested[i];
442 /* free up temporary matrix */
444 nr_free_matrix( h_trans_w_h, 1, Number_of_Controls,
445 1, Number_of_Controls );
453 const int Max_Cycles = 100;
457 if (Symbols_loaded) {
459 ls_trim_init(); /* Initialize Outputs & controls */
460 ls_trim_get_vals(); /* Limit the current control settings */
462 ls_trim_move_controls(); /* Write out the new values of controls */
463 ls_trim_put_controls();
464 ls_loop( 0.0, -1 ); /* Cycle the simulation once with new limited
467 /* Main trim cycle loop follows */
469 while((!Trimmed) && (Trim_Cycles < Max_Cycles))
476 ls_trim_save_baseline_outputs();
477 Trimmed = ls_trim_eval_outputs();
481 ls_trim_calc_h_column();
482 Controls[Index].Curr_Val = Saved_Control;
483 Controls[Index].Percent = Saved_Control_Percent;
484 Controls[Index].Requested_Percent = Saved_Control_Percent;
489 if (Index >= Number_of_Controls)
496 { /* Save the current value & pert next control */
498 Saved_Control = Controls[Index].Curr_Val;
499 Saved_Control_Percent = Controls[Index].Percent;
501 if (Controls[Index].Percent <
502 (1.0 - Controls[Index].Pert_Size) )
504 Controls[Index].Requested_Percent =
505 Controls[Index].Percent +
506 Controls[Index].Pert_Size ;
510 Controls[Index].Requested_Percent =
511 Controls[Index].Percent -
512 Controls[Index].Pert_Size;
515 ls_trim_move_controls();
516 ls_trim_put_controls();
522 nr_free_matrix( H_Partials, 1, Number_of_Controls, 1, Number_of_Controls );
525 if (!Trimmed) fprintf(stderr, "Trim unsuccessful.\n");
531 char *ls_trim_get_set(char *buffer, char *eob)
532 /* This routine parses the settings file for "trim" entries. */
535 static char *fac_name = FACILITY_NAME_STRING;
536 char *bufptr, **lasts, *nullptr, null = '\0';
538 int n, ver, i, error, abrt;
539 enum {controls_header, controls, outputs_header, outputs, done} looking_for;
544 looking_for = controls_header;
547 n = sscanf(buffer, "%s", line);
548 if (n == 0) return 0L;
549 if (strncasecmp( fac_name, line, strlen(fac_name) )) return 0L;
551 bufptr = strtok_r( buffer+strlen(fac_name)+1, "\n", lasts);
552 if (bufptr == 0) return 0L;
554 sscanf( bufptr, "%d", &ver );
555 if (ver != CURRENT_VERSION) return 0L;
557 while( !abrt && (eob > bufptr))
559 bufptr = strtok_r( 0L, "\n", lasts );
560 if (bufptr == 0) return 0L;
561 if (strncasecmp( bufptr, "end", 3) == 0) break;
563 sscanf( bufptr, "%s", line );
564 if (line[0] != '#') /* ignore comments */
568 case controls_header:
570 if (strncasecmp( line, "controls", 8) == 0)
572 n = sscanf( bufptr, "%s%d", line, &Number_of_Controls );
573 if (n != 2) abrt = 1;
574 looking_for = controls;
581 n = sscanf( bufptr, "%s%s%le%le%le",
582 Controls[i].Symbol.Mod_Name,
583 Controls[i].Symbol.Par_Name,
584 &Controls[i].Min_Val,
585 &Controls[i].Max_Val,
586 &Controls[i].Pert_Size);
587 if (n != 5) abrt = 1;
588 Controls[i].Symbol.Addr = NIL_POINTER;
590 if (i >= Number_of_Controls) looking_for = outputs_header;
595 if (strncasecmp( line, "outputs", 7) == 0)
597 n = sscanf( bufptr, "%s%d", line, &Number_of_Outputs );
598 if (n != 2) abrt = 1;
599 looking_for = outputs;
606 n = sscanf( bufptr, "%s%s%le",
607 Outputs[i].Symbol.Mod_Name,
608 Outputs[i].Symbol.Par_Name,
609 &Outputs[i].Trim_Criteria );
610 if (n != 3) abrt = 1;
611 Outputs[i].Symbol.Addr = NIL_POINTER;
613 if (i >= Number_of_Outputs) looking_for = done;
625 (Number_of_Controls > 0) &&
626 (Number_of_Outputs == Number_of_Controls))
630 for(i=0;i<Number_of_Controls;i++) /* Initialize fields in Controls data */
632 Controls[i].Curr_Val = ls_get_sym_val( &Controls[i].Symbol, &error );
634 Controls[i].Symbol.Addr = NIL_POINTER;
635 Controls[i].Authority = Controls[i].Max_Val - Controls[i].Min_Val;
636 if (Controls[i].Authority == 0.0)
637 Controls[i].Authority = 1.0;
638 Controls[i].Requested_Percent =
639 (Controls[i].Curr_Val - Controls[i].Min_Val)
640 /Controls[i].Authority;
641 Controls[i].Pert_Size = Controls[i].Pert_Size/Controls[i].Authority;
644 for (i=0;i<Number_of_Outputs;i++) /* Initialize fields in Outputs data */
646 Outputs[i].Curr_Val = ls_get_sym_val( &Outputs[i].Symbol, &error );
647 if (error) Outputs[i].Symbol.Addr = NIL_POINTER;
648 Outputs[i].Weighting =
649 Outputs[0].Trim_Criteria/Outputs[i].Trim_Criteria;
659 void ls_trim_put_set( FILE *fp )
665 fprintf(fp, "#============================== %s\n", FACILITY_NAME_STRING);
667 fprintf(fp, FACILITY_NAME_STRING);
669 fprintf(fp, "%04d\n", CURRENT_VERSION);
670 fprintf(fp, " controls: %d\n", Number_of_Controls);
671 fprintf(fp, "# module parameter min_val max_val pert_size\n");
672 for (i=0; i<Number_of_Controls; i++)
673 fprintf(fp, " %s\t%s\t%E\t%E\t%E\n",
674 Controls[i].Symbol.Mod_Name,
675 Controls[i].Symbol.Par_Name,
678 Controls[i].Pert_Size*Controls[i].Authority);
679 fprintf(fp, " outputs: %d\n", Number_of_Outputs);
680 fprintf(fp, "# module parameter trim_criteria\n");
681 for (i=0;i<Number_of_Outputs;i++)
682 fprintf(fp, " %s\t%s\t%E\n",
683 Outputs[i].Symbol.Mod_Name,
684 Outputs[i].Symbol.Par_Name,
685 Outputs[i].Trim_Criteria );
686 fprintf(fp, "end\n");