commit 597f5bc8e8ddd03c8779c7ce95e2fc06c2703aa3
Author: Andreas Gaeb <address@hidden>
Date:   Fri Jul 23 16:08:06 2010 +0200

    allow JSBSim to run multiple times per control loop execution

diff --git a/sw/simulator/sim_ac_jsbsim.c b/sw/simulator/sim_ac_jsbsim.c
index d7591e1..82e6282 100644
--- a/sw/simulator/sim_ac_jsbsim.c
+++ b/sw/simulator/sim_ac_jsbsim.c
@@ -69,6 +69,7 @@ static void sim_init(void) {
 }
 
 static gboolean sim_periodic(gpointer data __attribute__ ((unused))) {
+  static uint8_t ncalls = 0;
 
   /* read actuators positions and feed JSBSim inputs */
   copy_inputs_to_jsbsim(FDMExec);
@@ -84,11 +85,15 @@ static gboolean sim_periodic(gpointer data __attribute__ ((unused))) {
   /* read outputs from model state (and display ?) */
   copy_outputs_from_jsbsim(FDMExec);
 
-  /* run the airborne code */
-
+  /* run the airborne code
+     with 60 Hz, even if JSBSim runs with a multiple of this */
+  if (ncalls == 0) {
 //  airborne_run_one_step();
   autopilot_event_task();
   autopilot_periodic_task();
+  }
+  ++ncalls;
+  if (ncalls == JSBSIM_SPEEDUP) ncalls = 0;
 
   return result;
 }
diff --git a/sw/simulator/sim_ac_jsbsim.h b/sw/simulator/sim_ac_jsbsim.h
index e5c72a2..8984e4c 100644
--- a/sw/simulator/sim_ac_jsbsim.h
+++ b/sw/simulator/sim_ac_jsbsim.h
@@ -38,11 +38,13 @@
 
 #include <Ivy/ivy.h>
 
-/* 60Hz <-> 17ms */
 #ifndef JSBSIM_PERIOD
-#define JSBSIM_PERIOD 17
+#define JSBSIM_SPEEDUP 4 ///< how many JSBSim calls per A/P control loop call?
+#define JSBSIM_PERIOD (1000.0/CONTROL_RATE/JSBSIM_SPEEDUP) ///< JSBSim timestep in milliseconds
+#else
+#define JSBSIM_SPEEDUP ((uint8_t) (1000./CONTROL_RATE/JSBSIM_PERIOD))
 #endif
-#define DT (JSBSIM_PERIOD*1e-3)
+#define DT (JSBSIM_PERIOD*1e-3) ///< JSBSim timestep in seconds
 
 #define RAD2DEG 57.29578
 #define FT2M 0.3048