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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,189 @@ | ||
| import openmdao.api as om | ||
| import dymos as dm | ||
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|
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| def make_balanced_field_length_problem(ode_class, tx): | ||
| """ | ||
| Create a balanced field length problem and optionally set default values into it. | ||
| Parameters | ||
| ---------- | ||
| ode_class : System class | ||
| The Dymos ODE System class. | ||
| tx_class : Transcription | ||
| Transcription to use. | ||
| Returns | ||
| ------- | ||
| _type_ | ||
| _description_ | ||
| """ | ||
| p = om.Problem() | ||
|
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| p.driver = om.pyOptSparseDriver() | ||
| p.driver.declare_coloring() | ||
|
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| # Use IPOPT if available, with fallback to SLSQP | ||
| p.driver.options['optimizer'] = 'IPOPT' | ||
| p.driver.options['print_results'] = True | ||
|
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| p.driver.opt_settings['print_level'] = 0 | ||
| p.driver.opt_settings['mu_strategy'] = 'adaptive' | ||
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| p.driver.opt_settings['bound_mult_init_method'] = 'mu-based' | ||
| p.driver.opt_settings['mu_init'] = 0.01 | ||
| p.driver.opt_settings['nlp_scaling_method'] = 'gradient-based' | ||
|
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| # First Phase: Brake release to V1 - both engines operable | ||
| br_to_v1 = dm.Phase(ode_class=ode_class, transcription=tx, | ||
| ode_init_kwargs={'mode': 'runway'}) | ||
| br_to_v1.set_time_options(fix_initial=True, duration_bounds=(1, 1000), duration_ref=10.0) | ||
| br_to_v1.add_state('r', fix_initial=True, lower=0, ref=1000.0, defect_ref=1000.0) | ||
| br_to_v1.add_state('v', fix_initial=True, lower=0, ref=100.0, defect_ref=100.0) | ||
| br_to_v1.add_parameter('alpha', val=0.0, opt=False, units='deg') | ||
| br_to_v1.add_timeseries_output('*') | ||
|
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| # Second Phase: Rejected takeoff at V1 - no engines operable | ||
| rto = dm.Phase(ode_class=ode_class, transcription=tx, | ||
| ode_init_kwargs={'mode': 'runway'}) | ||
| rto.set_time_options(fix_initial=False, duration_bounds=(1, 1000), duration_ref=1.0) | ||
| rto.add_state('r', fix_initial=False, lower=0, ref=1000.0, defect_ref=1000.0) | ||
| rto.add_state('v', fix_initial=False, lower=0, ref=100.0, defect_ref=100.0) | ||
| rto.add_parameter('alpha', val=0.0, opt=False, units='deg') | ||
| rto.add_timeseries_output('*') | ||
|
|
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| # Third Phase: V1 to Vr - single engine operable | ||
| v1_to_vr = dm.Phase(ode_class=ode_class, transcription=tx, | ||
| ode_init_kwargs={'mode': 'runway'}) | ||
| v1_to_vr.set_time_options(fix_initial=False, duration_bounds=(1, 1000), duration_ref=1.0) | ||
| v1_to_vr.add_state('r', fix_initial=False, lower=0, ref=1000.0, defect_ref=1000.0) | ||
| v1_to_vr.add_state('v', fix_initial=False, lower=0, ref=100.0, defect_ref=100.0) | ||
| v1_to_vr.add_parameter('alpha', val=0.0, opt=False, units='deg') | ||
| v1_to_vr.add_timeseries_output('*') | ||
|
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| # Fourth Phase: Rotate - single engine operable | ||
| rotate = dm.Phase(ode_class=ode_class, transcription=tx, | ||
| ode_init_kwargs={'mode': 'runway'}) | ||
| rotate.set_time_options(fix_initial=False, duration_bounds=(1.0, 5), duration_ref=1.0) | ||
| rotate.add_state('r', fix_initial=False, lower=0, ref=1000.0, defect_ref=1000.0) | ||
| rotate.add_state('v', fix_initial=False, lower=0, ref=100.0, defect_ref=100.0) | ||
| rotate.add_control('alpha', order=1, opt=True, units='deg', lower=0, upper=10, ref=10, | ||
| val=[0, 10], control_type='polynomial') | ||
| rotate.add_timeseries_output('*') | ||
|
|
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| # Fifth Phase: Climb to target speed and altitude at end of runway. | ||
| climb = dm.Phase(ode_class=ode_class, transcription=tx, | ||
| ode_init_kwargs={'mode': 'climb'}) | ||
| climb.set_time_options(fix_initial=False, duration_bounds=(1, 100), duration_ref=1.0) | ||
| climb.add_state('r', fix_initial=False, lower=0, ref=1000.0, defect_ref=1000.0) | ||
| climb.add_state('h', fix_initial=True, lower=0, ref=1.0, defect_ref=1.0) | ||
| climb.add_state('v', fix_initial=False, lower=0, ref=100.0, defect_ref=100.0) | ||
| climb.add_state('gam', fix_initial=True, lower=0, ref=0.05, defect_ref=0.05) | ||
| climb.add_control('alpha', opt=True, units='deg', lower=-10, upper=15, ref=10) | ||
| climb.add_timeseries_output('*') | ||
|
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| # Instantiate the trajectory and add phases | ||
| traj = dm.Trajectory() | ||
| p.model.add_subsystem('traj', traj) | ||
| traj.add_phase('br_to_v1', br_to_v1) | ||
| traj.add_phase('rto', rto) | ||
| traj.add_phase('v1_to_vr', v1_to_vr) | ||
| traj.add_phase('rotate', rotate) | ||
| traj.add_phase('climb', climb) | ||
|
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| all_phases = ['br_to_v1', 'v1_to_vr', 'rto', 'rotate', 'climb'] | ||
| groundroll_phases = ['br_to_v1', 'v1_to_vr', 'rto', 'rotate'] | ||
|
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| # Add parameters common to multiple phases to the trajectory | ||
| traj.add_parameter('m', val=174200., opt=False, units='lbm', | ||
| desc='aircraft mass', | ||
| targets={phase: ['m'] for phase in all_phases}) | ||
|
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| # Handle parameters which change from phase to phase. | ||
| traj.add_parameter('T_nominal', val=27000 * 2, opt=False, units='lbf', static_target=True, | ||
| desc='nominal aircraft thrust', | ||
| targets={'br_to_v1': ['T']}) | ||
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| traj.add_parameter('T_engine_out', val=27000, opt=False, units='lbf', static_target=True, | ||
| desc='thrust under a single engine', | ||
| targets={'v1_to_vr': ['T'], 'rotate': ['T'], 'climb': ['T']}) | ||
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| traj.add_parameter('T_shutdown', val=0.0, opt=False, units='lbf', static_target=True, | ||
| desc='thrust when engines are shut down for rejected takeoff', | ||
| targets={'rto': ['T']}) | ||
|
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| traj.add_parameter('mu_r_nominal', val=0.03, opt=False, units=None, static_target=True, | ||
| desc='nominal runway friction coefficient', | ||
| targets={'br_to_v1': ['mu_r'], 'v1_to_vr': ['mu_r'], 'rotate': ['mu_r']}) | ||
|
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| traj.add_parameter('mu_r_braking', val=0.3, opt=False, units=None, static_target=True, | ||
| desc='runway friction coefficient under braking', | ||
| targets={'rto': ['mu_r']}) | ||
|
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| traj.add_parameter('h_runway', val=0., opt=False, units='ft', | ||
| desc='runway altitude', | ||
| targets={phase: ['h'] for phase in groundroll_phases}) | ||
|
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| # Here we're omitting some constants that are common throughout all phases for the sake of brevity. | ||
| # Their correct defaults are specified in add_input calls to `wrap_ode_func`. | ||
|
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| # Standard "end of first phase to beginning of second phase" linkages | ||
| # Alpha changes from being a parameter in v1_to_vr to a polynomial control | ||
| # in rotate, to a dynamic control in `climb`. | ||
| traj.link_phases(['br_to_v1', 'v1_to_vr'], vars=['time', 'r', 'v']) | ||
| traj.link_phases(['v1_to_vr', 'rotate'], vars=['time', 'r', 'v', 'alpha']) | ||
| traj.link_phases(['rotate', 'climb'], vars=['time', 'r', 'v', 'alpha']) | ||
| traj.link_phases(['br_to_v1', 'rto'], vars=['time', 'r', 'v']) | ||
|
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| # Less common "final value of r must match at ends of two phases". | ||
| traj.add_linkage_constraint(phase_a='rto', var_a='r', loc_a='final', | ||
| phase_b='climb', var_b='r', loc_b='final', | ||
| ref=1000) | ||
|
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| # Define the constraints and objective for the optimal control problem | ||
| v1_to_vr.add_boundary_constraint('v_over_v_stall', loc='final', lower=1.2, ref=100) | ||
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| rto.add_boundary_constraint('v', loc='final', equals=0., ref=100, linear=True) | ||
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| rotate.add_boundary_constraint('F_r', loc='final', equals=0, ref=100000) | ||
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| climb.add_boundary_constraint('h', loc='final', equals=35, ref=35, units='ft', linear=True) | ||
| climb.add_boundary_constraint('gam', loc='final', equals=5, ref=5, units='deg', linear=True) | ||
| climb.add_path_constraint('gam', lower=0, upper=5, ref=5, units='deg') | ||
| climb.add_boundary_constraint('v_over_v_stall', loc='final', lower=1.25, ref=1.25) | ||
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| rto.add_objective('r', loc='final', ref=1000.0) | ||
|
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| # | ||
| # Setup the problem and set the initial guess | ||
| # | ||
| p.setup(check=True) | ||
|
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| br_to_v1.set_time_val(initial=0.0, duration=35.0) | ||
| br_to_v1.set_state_val('r', [0, 2500.0]) | ||
| br_to_v1.set_state_val('v', [0.0001, 100.0]) | ||
| br_to_v1.set_parameter_val('alpha', 0.0, units='deg') | ||
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| v1_to_vr.set_time_val(initial=35.0, duration=35.0) | ||
| v1_to_vr.set_state_val('r', [2500, 300.0]) | ||
| v1_to_vr.set_state_val('v', [100, 110.0]) | ||
| v1_to_vr.set_parameter_val('alpha', 0.0, units='deg') | ||
|
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| rto.set_time_val(initial=35.0, duration=1.0) | ||
| rto.set_state_val('r', [2500, 5000.0]) | ||
| rto.set_state_val('v', [110, 0.0001]) | ||
| rto.set_parameter_val('alpha', 0.0, units='deg') | ||
|
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| rotate.set_time_val(initial=35.0, duration=5.0) | ||
| rotate.set_state_val('r', [1750, 1800.0]) | ||
| rotate.set_state_val('v', [80, 85.0]) | ||
| rotate.set_control_val('alpha', 0.0, units='deg') | ||
|
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| climb.set_time_val(initial=30.0, duration=20.0) | ||
| climb.set_state_val('r', [5000, 5500.0], units='ft') | ||
| climb.set_state_val('v', [160, 170.0], units='kn') | ||
| climb.set_state_val('h', [0.0, 35.0], units='ft') | ||
| climb.set_state_val('gam', [0.0, 5.0], units='deg') | ||
| climb.set_control_val('alpha', 5.0, units='deg') | ||
|
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| return p |
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