########################################################################## # Simple Brake Simulation System # 2010, Thorsten Brehm # # Simple simulation of brake energy absorption and cooling effects. # # This module computes (approximates... :-) ) an energy level which # (faintly) resembles the kinetic energy absorption and cooling effects # of a brake system. But instead of computing real temperatures, this # is just meant to distinguish normal energy levels from exceptionally # high levels. The target is to drive EICAS "brakes overheat" messages # and gear effects only, to "reward" pilots with exceptionally bad # landings... # # To avoid complicated calculations of different braking effects (roll/air # drag, reverse thrust etc), we simply assume the brake system to cause a # fixed deceleration (me.BrakeDecel). With this deceleration we approximate # the speed difference which would be caused by the brake system alone for # any given simulation interval. The difference of the kinetic energy level # at the current speed and the decelerated speed are then added up to the # total absorbed brake energy. # Units (knots/lbs/Kg) do not matter much here. Eventually a magic scaling # divisor is used to scale the output level. Any output > 1 means # "overheated brakes", any level <=1 means "brake temperature OK". # No exact science here - but good enough for now :-). ########################################################################## # # Added brakes temp calculations and adapted for A320-family # 2020, Andrea Vezzali # ########################################################################## var BrakeSystem = { new : func() { var m = { parents : [BrakeSystem]}; # deceleration caused by brakes alone (knots/s2) m.BrakeDecel = 1.0; # kt/s^2 # Higher value means quicker cooling m.CoolingFactor = 0.000125; # Scaling divisor. Use this to scale the energy output. # Manually tune this value: a total energy output # at "/gear/brake-thermal-energy" > 1.0 means overheated brakes, # anything below <= 1.0 means energy absorbed by brakes is OK. #m.ScalingDivisor= 700000*450.0; m.ScalingDivisor = 0.000000006; m.LSmokeActive = 0; m.LSmokeToggle = 0; m.RSmokeActive = 0; m.RSmokeToggle = 0; # m.LnCoolFactor = math.ln(1-m.CoolingFactor); m.reset(); return m; }, reset : func() { # Initial thermal energy setprop("gear/gear[1]/Lbrake-thermal-energy",0.0); setprop("gear/gear[2]/Rbrake-thermal-energy",0.0); setprop("controls/gear/brake-fans",0); setprop("gear/gear[1]/Lbrake-smoke",0); setprop("gear/gear[2]/Rbrake-smoke",0); setprop("gear/gear[1]/L-Thrust",0); setprop("gear/gear[2]/R-Thrust",0); #Introducing a random error on temp sensors (max 5°C) setprop("gear/gear[1]/L1error-temp-degc", math.round(rand()*(5)) - 2.5); setprop("gear/gear[1]/L2error-temp-degc", math.round(rand()*(5)) - 2.5); setprop("gear/gear[2]/R3error-temp-degc", math.round(rand()*(5)) - 2.5); setprop("gear/gear[2]/R4error-temp-degc", math.round(rand()*(5)) - 2.5); <<<<<<< HEAD #var atemp = getprop("environment/temperature-degc") or 0; #var vmach = getprop("velocities/mach") or 0; var tatdegc = getprop("/systems/navigation/probes/tat-1/compute-tat") or 0; ======= var atemp = getprop("environment/temperature-degc") or 0; var vmach = getprop("velocities/mach") or 0; var tatdegc = getprop("systems/navigation/probes/tat-1/compute-tat"); >>>>>>> d47b3431d233eb890aa9e256c21f148e6dce5a21 setprop("gear/gear[1]/L1brake-temp-degc",tatdegc+getprop("gear/gear[1]/L1error-temp-degc")); setprop("gear/gear[1]/L2brake-temp-degc",tatdegc+getprop("gear/gear[1]/L2error-temp-degc")); setprop("gear/gear[2]/R3brake-temp-degc",tatdegc+getprop("gear/gear[2]/R3error-temp-degc")); setprop("gear/gear[2]/R4brake-temp-degc",tatdegc+getprop("gear/gear[2]/R4error-temp-degc")); setprop("sim/animation/fire-services",0); me.LastSimTime = 0.0; }, # update brake energy update : func() { var CurrentTime = getprop("sim/time/elapsed-sec"); var dt = CurrentTime - me.LastSimTime; var LThermalEnergy = getprop("gear/gear[1]/Lbrake-thermal-energy"); var RThermalEnergy = getprop("gear/gear[2]/Rbrake-thermal-energy"); var LBrakeLevel = getprop("fdm/jsbsim/fcs/left-brake-cmd-norm"); var RBrakeLevel = getprop("fdm/jsbsim/fcs/right-brake-cmd-norm"); #var atemp = getprop("environment/temperature-degc") or 0; #var vmach = getprop("velocities/mach") or 0; #var tatdegc = atemp * (1 + (0.2 * math.pow(vmach, 2))); var tatdegc = getprop("/systems/navigation/probes/tat-1/compute-tat") or 0; var L_thrust_lb = getprop("engines/engine[0]/thrust_lb"); var R_thrust_lb = getprop("engines/engine[1]/thrust_lb"); if (dt<1.0) { var OnGround = getprop("gear/gear[1]/wow"); #cooling effect: adjust cooling factor by a value proportional to the environment temp (m.CoolingFactor + environment temp-degc * 0.00001) var LCoolingRatio = me.CoolingFactor+(tatdegc*0.000001); var RCoolingRatio = me.CoolingFactor+(tatdegc*0.000001); if (getprop("controls/gear/brake-fans")) { #increase CoolingRatio if Brake Fans are active LCoolingRatio = LCoolingRatio * 3; RCoolingRatio = RCoolingRatio * 3; } if (getprop("gear/gear[1]/position-norm")) { #increase CoolingRatio if gear down according to airspeed LCoolingRatio = LCoolingRatio * getprop("velocities/airspeed-kt"); } else { #Reduced CoolingRatio if gear up LCoolingRatio = LCoolingRatio * 0.1; } if (getprop("gear/gear[2]/position-norm")) { #increase CoolingRatio if gear down according to airspeed RCoolingRatio = RCoolingRatio * getprop("velocities/airspeed-kt"); } else { #Reduced CoolingRatio if gear up RCoolingRatio = RCoolingRatio * 0.1; } if (LBrakeLevel>0) { #Reduced CoolingRatio if Brakes used LCoolingRatio = LCoolingRatio * 0.1 * LBrakeLevel; } if (RBrakeLevel>0) { #Reduced CoolingRatio if Brakes used RCoolingRatio = RCoolingRatio * 0.1 * RBrakeLevel; } var LnCoolFactor = math.ln(1-LCoolingRatio); var RnCoolFactor = math.ln(1-RCoolingRatio); L_thrust_lb = math.abs(getprop("engines/engine[0]/thrust_lb")); if (L_thrust_lb < 1) { L_thrust_lb = 1 } #Disabling thrust computation on Brakes temperature #L_Thrust = math.pow((math.log10(L_thrust_lb)),10)*0.0000000002; L_Thrust = 0; R_thrust_lb = math.abs(getprop("engines/engine[1]/thrust_lb")); if (R_thrust_lb < 1) { R_thrust_lb = 1 } #Disabling thrust computation on Brakes temperature #R_Thrust = math.pow((math.log10(R_thrust_lb)),10)*0.0000000002; R_Thrust = 0; if (OnGround) { var V1 = getprop("velocities/groundspeed-kt"); var Mass = getprop("fdm/jsbsim/inertia/weight-lbs")*(me.ScalingDivisor); # absorb some kinetic energy: # dE= 1/2 * m * V1^2 - 1/2 * m * V2^2) var V2_L = V1 - me.BrakeDecel * dt * LBrakeLevel; var V2_R = V1 - me.BrakeDecel * dt * RBrakeLevel; #TODO - Adjust ThermalEnergy according to differential braking #LBrakeLevel-RBrakeLevel LThermalEnergy += (Mass * (math.pow(V1, 2) - math.pow(V2_L, 2)) / 2); if (getprop("services/chocks/left")) { if (!getprop("controls/gear/brake-parking")) { # cooling effect: reduce thermal energy by (LnCoolFactor) * dt LThermalEnergy = LThermalEnergy * math.exp(LnCoolFactor * dt); } else { #LThermalEnergy += L_Thrust; # cooling effect: reduce thermal energy by (LnCoolFactor) * dt LThermalEnergy = (LThermalEnergy * math.exp(LnCoolFactor * dt)) + (L_Thrust * dt); } } else { if (!getprop("controls/gear/brake-parking")) { if (LBrakeLevel>0) { if (V2_L>0) { #LThermalEnergy += (Mass * (math.pow(V1, 2) - math.pow(V2_L, 2)) / 2) + L_thrust; # cooling effect: reduce thermal energy by (LnCoolFactor) * dt LThermalEnergy = LThermalEnergy * math.exp(LnCoolFactor * dt); } else { #LThermalEnergy += math.abs(L_Thrust); # cooling effect: reduce thermal energy by (LnCoolFactor) * dt LThermalEnergy = (LThermalEnergy * math.exp(LnCoolFactor * dt)) + (L_Thrust * dt); } } else { # cooling effect: reduce thermal energy by (LnCoolFactor) * dt LThermalEnergy = LThermalEnergy * math.exp(LnCoolFactor * dt); } } else { #LThermalEnergy += math.abs(L_Thrust); # cooling effect: reduce thermal energy by (LnCoolFactor) * dt LThermalEnergy = (LThermalEnergy * math.exp(LnCoolFactor * dt)) + (L_Thrust * dt); } } RThermalEnergy += (Mass * (math.pow(V1, 2) - math.pow(V2_R, 2)) / 2); if (getprop("services/chocks/right")) { if (!getprop("controls/gear/brake-parking")) { # cooling effect: reduce thermal energy by (RnCoolFactor) * dt RThermalEnergy = RThermalEnergy * math.exp(RnCoolFactor * dt); } else { #RThermalEnergy += math.abs(R_Thrust); # cooling effect: reduce thermal energy by (RnCoolFactor) * dt RThermalEnergy = (RThermalEnergy * math.exp(RnCoolFactor * dt)) + (R_Thrust * dt); } } else { if (!getprop("controls/gear/brake-parking")) { if (RBrakeLevel>0) { if (V2_R>0) { #RThermalEnergy += (Mass * (math.pow(V1, 2) - math.pow(V2_R, 2)) / 2) + R_thrust; # cooling effect: reduce thermal energy by (RnCoolFactor) * dt RThermalEnergy = RThermalEnergy * math.exp(RnCoolFactor * dt); } else { #RThermalEnergy += math.abs(R_Thrust); # cooling effect: reduce thermal energy by (RnCoolFactor) * dt RThermalEnergy = (RThermalEnergy * math.exp(RnCoolFactor * dt)) + (R_Thrust * dt); } } else { # cooling effect: reduce thermal energy by (RnCoolFactor) * dt RThermalEnergy = RThermalEnergy * math.exp(RnCoolFactor * dt); } } else { #RThermalEnergy += math.abs(R_Thrust); # cooling effect: reduce thermal energy by (RnCoolFactor) * dt RThermalEnergy = (RThermalEnergy * math.exp(RnCoolFactor * dt)) + (R_Thrust * dt); } } } else { LThermalEnergy = LThermalEnergy * math.exp(LnCoolFactor * dt); RThermalEnergy = RThermalEnergy * math.exp(RnCoolFactor * dt); } if (LThermalEnergy < 0) { LThermalEnergy = 0 } if (LThermalEnergy > 3) { LThermalEnergy = 3 } if (RThermalEnergy < 0) { RThermalEnergy = 0 } if (RThermalEnergy > 3) { RThermalEnergy = 3 } setprop("gear/gear[1]/L-Thrust",L_Thrust); setprop("gear/gear[2]/R-Thrust",R_Thrust); setprop("gear/gear[1]/Lbrake-thermal-energy",LThermalEnergy); setprop("gear/gear[2]/Rbrake-thermal-energy",RThermalEnergy); #Calculating Brakes temperature setprop("gear/gear[1]/L1brake-temp-degc",tatdegc+getprop("gear/gear[1]/L1error-temp-degc")+(LThermalEnergy * (300-tatdegc-getprop("gear/gear[1]/L1error-temp-degc")))); setprop("gear/gear[1]/L2brake-temp-degc",tatdegc+getprop("gear/gear[1]/L2error-temp-degc")+(LThermalEnergy * (300-tatdegc-getprop("gear/gear[1]/L2error-temp-degc")))); setprop("gear/gear[2]/R3brake-temp-degc",tatdegc+getprop("gear/gear[2]/R3error-temp-degc")+(RThermalEnergy * (300-tatdegc-getprop("gear/gear[2]/R3error-temp-degc")))); setprop("gear/gear[2]/R4brake-temp-degc",tatdegc+getprop("gear/gear[2]/R4error-temp-degc")+(RThermalEnergy * (300-tatdegc-getprop("gear/gear[2]/R4error-temp-degc")))); if ((LThermalEnergy>1)and(!me.LSmokeActive)) { # start smoke processing me.LSmokeActive = 1; settimer(func { BrakeSys.Lsmoke(); },0); } if ((RThermalEnergy>1)and(!me.RSmokeActive)) { # start smoke processing me.RSmokeActive = 1; settimer(func { BrakeSys.Rsmoke(); },0); } } me.LastSimTime = CurrentTime; # 5 updates per second are good enough settimer(func { BrakeSys.update(); },0.2); }, # smoke processing Lsmoke : func() { if ((me.LSmokeActive)and(getprop("gear/gear[1]/Lbrake-thermal-energy")>1)) { # make density of smoke effect depend on energy level var LSmokeDelay=0; var LThermalEnergy = getprop("gear/gear[1]/Lbrake-thermal-energy"); if (LThermalEnergy < 1.5) LSmokeDelay=(1.5-LThermalEnergy); # No smoke when gear retracted var LSmokeValue = (getprop("gear/gear[1]/position-norm")>0.5); # toggle smoke to interpolate different densities if (LSmokeDelay>0.05) { me.LSmokeToggle = !me.LSmokeToggle; if (!me.LSmokeToggle) LSmokeValue = 0; else LSmokeDelay = 0; } setprop("gear/gear[1]/Lbrake-smoke",LSmokeValue); settimer(func { BrakeSys.Lsmoke(); },LSmokeDelay); } else { # stop smoke processing setprop("gear/gear[1]/Lbrake-smoke",0); setprop("sim/animation/fire-services",0); me.LSmokeActive = 0; } if (getprop("gear/gear[1]/Lbrake-thermal-energy") > 1.5) setprop("sim/animation/fire-services",1); else setprop("sim/animation/fire-services",0); }, # smoke processing Rsmoke : func() { if ((me.RSmokeActive)and(getprop("gear/gear[2]/Rbrake-thermal-energy")>1)) { # make density of smoke effect depend on energy level var RSmokeDelay=0; var RThermalEnergy = getprop("gear/gear[2]/Rbrake-thermal-energy"); if (RThermalEnergy < 1.5) RSmokeDelay=(1.5-RThermalEnergy); # No smoke when gear retracted var RSmokeValue = (getprop("gear/gear[2]/position-norm")>0.5); # toggle smoke to interpolate different densities if (RSmokeDelay>0.05) { me.RSmokeToggle = !me.RSmokeToggle; if (!me.RSmokeToggle) RSmokeValue = 0; else RSmokeDelay = 0; } setprop("gear/gear[2]/Rbrake-smoke",RSmokeValue); settimer(func { BrakeSys.Rsmoke(); },RSmokeDelay); } else { # stop smoke processing setprop("gear/gear[2]/Rbrake-smoke",0); me.RSmokeActive = 0; } if (getprop("gear/gear[2]/Rbrake-thermal-energy") > 1.5) setprop("sim/animation/fire-services",1); else setprop("sim/animation/fire-services",0); }, }; var BrakeSys = BrakeSystem.new(); setlistener("sim/signals/fdm-initialized", # executed on _every_ FDM reset (but not installing new listeners) func(idle) { BrakeSys.reset(); }, 0,0); settimer(func() { BrakeSys.update(); }, 5);