DATE PURPOSE BY
3/17/00 Initial test release
-
+ 3/09/01 Added callout to UIUC gear function. (DPM)
+ 6/18/01 Added call out to UIUC record routine (RD)
----------------------------------------------------------------------------
uiuc_engine_routine();
}
-/* ***********************************************************************
- * Gear model. Exact copy of C172_gear.c. Additional gear models will be
- * added later and the choice of the gear model could be specified at
- * runtime.
- * ***********************************************************************/
-static void sub3( DATA v1[], DATA v2[], DATA result[] )
-{
- result[0] = v1[0] - v2[0];
- result[1] = v1[1] - v2[1];
- result[2] = v1[2] - v2[2];
-}
-
-static void add3( DATA v1[], DATA v2[], DATA result[] )
-{
- result[0] = v1[0] + v2[0];
- result[1] = v1[1] + v2[1];
- result[2] = v1[2] + v2[2];
-}
-
-static void cross3( DATA v1[], DATA v2[], DATA result[] )
-{
- result[0] = v1[1]*v2[2] - v1[2]*v2[1];
- result[1] = v1[2]*v2[0] - v1[0]*v2[2];
- result[2] = v1[0]*v2[1] - v1[1]*v2[0];
-}
-
-static void multtrans3x3by3( DATA m[][3], DATA v[], DATA result[] )
-{
- result[0] = m[0][0]*v[0] + m[1][0]*v[1] + m[2][0]*v[2];
- result[1] = m[0][1]*v[0] + m[1][1]*v[1] + m[2][1]*v[2];
- result[2] = m[0][2]*v[0] + m[1][2]*v[1] + m[2][2]*v[2];
-}
-
-static void mult3x3by3( DATA m[][3], DATA v[], DATA result[] )
-{
- result[0] = m[0][0]*v[0] + m[0][1]*v[1] + m[0][2]*v[2];
- result[1] = m[1][0]*v[0] + m[1][1]*v[1] + m[1][2]*v[2];
- result[2] = m[2][0]*v[0] + m[2][1]*v[1] + m[2][2]*v[2];
-}
-static void clear3( DATA v[] )
+void uiuc_gear ()
{
- v[0] = 0.; v[1] = 0.; v[2] = 0.;
+ uiuc_gear_routine();
}
-void uiuc_gear()
+void uiuc_record(SCALAR dt)
{
-char rcsid[] = "$Id$";
-
- /*
- * Aircraft specific initializations and data goes here
- */
-
-#define NUM_WHEELS 3
-
- static int num_wheels = NUM_WHEELS; /* number of wheels */
- static DATA d_wheel_rp_body_v[NUM_WHEELS][3] = /* X, Y, Z locations */
- {
- { 10., 0., 4. }, /* in feet */
- { -1., 3., 4. },
- { -1., -3., 4. }
- };
- static DATA spring_constant[NUM_WHEELS] = /* springiness, lbs/ft */
- { 1500., 5000., 5000. };
- static DATA spring_damping[NUM_WHEELS] = /* damping, lbs/ft/sec */
- { 100., 150., 150. };
- static DATA percent_brake[NUM_WHEELS] = /* percent applied braking */
- { 0., 0., 0. }; /* 0 = none, 1 = full */
- static DATA caster_angle_rad[NUM_WHEELS] = /* steerable tires - in */
- { 0., 0., 0.}; /* radians, +CW */
- /*
- * End of aircraft specific code
- */
-
- /*
- * Constants & coefficients for tyres on tarmac - ref [1]
- */
-
- /* skid function looks like:
- *
- * mu ^
- * |
- * max_mu | +
- * | /|
- * sliding_mu | / +------
- * | /
- * | /
- * +--+------------------------>
- * | | | sideward V
- * 0 bkout skid
- * V V
- */
-
-
- static DATA sliding_mu = 0.5;
- static DATA rolling_mu = 0.01;
- static DATA max_brake_mu = 0.6;
- static DATA max_mu = 0.8;
- static DATA bkout_v = 0.1;
- static DATA skid_v = 1.0;
- /*
- * Local data variables
- */
-
- DATA d_wheel_cg_body_v[3]; /* wheel offset from cg, X-Y-Z */
- DATA d_wheel_cg_local_v[3]; /* wheel offset from cg, N-E-D */
- DATA d_wheel_rwy_local_v[3]; /* wheel offset from rwy, N-E-U */
- DATA v_wheel_body_v[3]; /* wheel velocity, X-Y-Z */
- DATA v_wheel_local_v[3]; /* wheel velocity, N-E-D */
- DATA f_wheel_local_v[3]; /* wheel reaction force, N-E-D */
- DATA temp3a[3], temp3b[3], tempF[3], tempM[3];
- DATA reaction_normal_force; /* wheel normal (to rwy) force */
- DATA cos_wheel_hdg_angle, sin_wheel_hdg_angle; /* temp storage */
- DATA v_wheel_forward, v_wheel_sideward, abs_v_wheel_sideward;
- DATA forward_mu, sideward_mu; /* friction coefficients */
- DATA beta_mu; /* breakout friction slope */
- DATA forward_wheel_force, sideward_wheel_force;
-
- int i; /* per wheel loop counter */
-
- /*
- * Execution starts here
- */
-
- beta_mu = max_mu/(skid_v-bkout_v);
- clear3( F_gear_v ); /* Initialize sum of forces... */
- clear3( M_gear_v ); /* ...and moments */
-
- /*
- * Put aircraft specific executable code here
- */
-
- percent_brake[1] = 0.; /* replace with cockpit brake handle connection code */
- percent_brake[2] = percent_brake[1];
-
- caster_angle_rad[0] = 0.03*Rudder_pedal;
-
- for (i=0;i<num_wheels;i++) /* Loop for each wheel */
- {
- /*========================================*/
- /* Calculate wheel position w.r.t. runway */
- /*========================================*/
-
- /* First calculate wheel location w.r.t. cg in body (X-Y-Z) axes... */
-
- sub3( d_wheel_rp_body_v[i], D_cg_rp_body_v, d_wheel_cg_body_v );
-
- /* then converting to local (North-East-Down) axes... */
-
- multtrans3x3by3( T_local_to_body_m, d_wheel_cg_body_v, d_wheel_cg_local_v );
-
- /* Runway axes correction - third element is Altitude, not (-)Z... */
-
- d_wheel_cg_local_v[2] = -d_wheel_cg_local_v[2]; /* since altitude = -Z */
-
- /* Add wheel offset to cg location in local axes */
-
- add3( d_wheel_cg_local_v, D_cg_rwy_local_v, d_wheel_rwy_local_v );
-
- /* remove Runway axes correction so right hand rule applies */
-
- d_wheel_cg_local_v[2] = -d_wheel_cg_local_v[2]; /* now Z positive down */
-
- /*============================*/
- /* Calculate wheel velocities */
- /*============================*/
-
- /* contribution due to angular rates */
-
- cross3( Omega_body_v, d_wheel_cg_body_v, temp3a );
-
- /* transform into local axes */
-
- multtrans3x3by3( T_local_to_body_m, temp3a, temp3b );
-
- /* plus contribution due to cg velocities */
-
- add3( temp3b, V_local_rel_ground_v, v_wheel_local_v );
-
-
- /*===========================================*/
- /* Calculate forces & moments for this wheel */
- /*===========================================*/
-
- /* Add any anticipation, or frame lead/prediction, here... */
-
- /* no lead used at present */
-
- /* Calculate sideward and forward velocities of the wheel
- in the runway plane */
-
- cos_wheel_hdg_angle = cos(caster_angle_rad[i] + Psi);
- sin_wheel_hdg_angle = sin(caster_angle_rad[i] + Psi);
-
- v_wheel_forward = v_wheel_local_v[0]*cos_wheel_hdg_angle
- + v_wheel_local_v[1]*sin_wheel_hdg_angle;
- v_wheel_sideward = v_wheel_local_v[1]*cos_wheel_hdg_angle
- - v_wheel_local_v[0]*sin_wheel_hdg_angle;
-
- /* Calculate normal load force (simple spring constant) */
-
- reaction_normal_force = 0.;
- if( d_wheel_rwy_local_v[2] < 0. )
- {
- reaction_normal_force = spring_constant[i]*d_wheel_rwy_local_v[2]
- - v_wheel_local_v[2]*spring_damping[i];
- if (reaction_normal_force > 0.) reaction_normal_force = 0.;
- /* to prevent damping component from swamping spring component */
- }
-
- /* Calculate friction coefficients */
-
- forward_mu = (max_brake_mu - rolling_mu)*percent_brake[i] + rolling_mu;
- abs_v_wheel_sideward = sqrt(v_wheel_sideward*v_wheel_sideward);
- sideward_mu = sliding_mu;
- if (abs_v_wheel_sideward < skid_v)
- sideward_mu = (abs_v_wheel_sideward - bkout_v)*beta_mu;
- if (abs_v_wheel_sideward < bkout_v) sideward_mu = 0.;
-
- /* Calculate foreward and sideward reaction forces */
-
- forward_wheel_force = forward_mu*reaction_normal_force;
- sideward_wheel_force = sideward_mu*reaction_normal_force;
- if(v_wheel_forward < 0.) forward_wheel_force = -forward_wheel_force;
- if(v_wheel_sideward < 0.) sideward_wheel_force = -sideward_wheel_force;
-
- /* Rotate into local (N-E-D) axes */
-
- f_wheel_local_v[0] = forward_wheel_force*cos_wheel_hdg_angle
- - sideward_wheel_force*sin_wheel_hdg_angle;
- f_wheel_local_v[1] = forward_wheel_force*sin_wheel_hdg_angle
- + sideward_wheel_force*cos_wheel_hdg_angle;
- f_wheel_local_v[2] = reaction_normal_force;
-
- /* Convert reaction force from local (N-E-D) axes to body (X-Y-Z) */
-
- mult3x3by3( T_local_to_body_m, f_wheel_local_v, tempF );
-
- /* Calculate moments from force and offsets in body axes */
-
- cross3( d_wheel_cg_body_v, tempF, tempM );
-
- /* Sum forces and moments across all wheels */
-
- add3( tempF, F_gear_v, F_gear_v );
- add3( tempM, M_gear_v, M_gear_v );
-
- }
+ uiuc_record_routine(dt);
}
projects / flightgear.git / blobdiff