Pterasim MCP Server

Instructions

Implementation Reference

• src/pterasim_mcp/core.py:14-49 (handler)

  Core implementation of the pterasim.simulate tool: orchestrates high-fidelity (PteraSoftware UVLM) or analytic surrogate simulation for flapping wing aerodynamics.
  def simulate_pterasim(inputs: PterasimInput) -> PterasimOutput: """Simulate flapping wing performance.""" if inputs.prefer_high_fidelity and is_available(): try: result = run_high_fidelity(inputs) if result is not None: return result except Exception as exc: # pragma: no cover - fallback path LOGGER.warning("High-fidelity PteraSoftware run failed, falling back to surrogate: %s", exc) return _analytic_surrogate(inputs) def _analytic_surrogate(inputs: PterasimInput) -> PterasimOutput: rho = inputs.air_density_kg_m3 omega = 2.0 * math.pi * inputs.stroke_frequency_hz aspect_ratio = inputs.span_m**2 / inputs.planform_area_m2 cl = inputs.cl_alpha_per_rad * inputs.stroke_amplitude_rad dynamic_pressure = 0.5 * rho * max(inputs.cruise_velocity_m_s, 0.1) ** 2 heave_q = 0.5 * rho * inputs.planform_area_m2 * (omega * inputs.stroke_amplitude_rad) ** 2 lift = dynamic_pressure * inputs.planform_area_m2 * cl + heave_q induced = 0.0 if aspect_ratio > 0: induced = (cl**2) / (math.pi * aspect_ratio * 0.9) cd = inputs.cd0 + induced drag = dynamic_pressure * inputs.planform_area_m2 * cd thrust = drag moment_arm = ( inputs.tail_moment_arm_m if inputs.tail_moment_arm_m is not None else inputs.span_m / 4.0 ) torque = lift * moment_arm metadata = { "solver": "analytic", } return PterasimOutput(thrust_N=thrust, lift_N=lift, torque_Nm=torque, metadata=metadata)
• src/pterasim_mcp/models.py:8-29 (schema)

  Pydantic schemas defining the input parameters and output structure for the pterasim.simulate tool.
  class PterasimInput(BaseModel): span_m: float = Field(..., gt=0.0) mean_chord_m: float = Field(..., gt=0.0) stroke_frequency_hz: float = Field(..., ge=0.0) stroke_amplitude_rad: float = Field(..., ge=0.0) cruise_velocity_m_s: float = Field(..., ge=0.0) air_density_kg_m3: float = Field(..., gt=0.0) cl_alpha_per_rad: float = Field(...) cd0: float = Field(..., ge=0.0) planform_area_m2: float = Field(..., gt=0.0) tail_moment_arm_m: float | None = Field(default=None, ge=0.0) prefer_high_fidelity: bool = Field( default=True, description="Attempt to use PteraSoftware when available before falling back to the analytic surrogate.", ) class PterasimOutput(BaseModel): thrust_N: float lift_N: float torque_Nm: float metadata: dict[str, object] | None = Field(default=None, description="Solver details and diagnostics")
• src/pterasim_mcp/tool.py:14-25 (registration)

  MCP tool registration using FastMCP, with thin wrapper delegating to core handler.
  @app.tool( name="pterasim.simulate", description=( "Generate aerodynamic coefficients with UVLM fallback. " "Supply wing geometry, flapping schedule, and timestep count. " "Returns forces, torques, and solver metadata. " "Example: {\"span_m\":0.8,\"chord_m\":0.12,\"num_timesteps\":180}" ), meta={"version": "0.1.0", "categories": ["aero", "simulation"]}, ) def simulate(request: PterasimInput) -> PterasimOutput: return simulate_pterasim(request)
• src/pterasim_mcp/pterasoftware_adapter.py:22-101 (helper)

  High-fidelity aerodynamic simulation helper using PteraSoftware's UVLM solver, called conditionally by the handler.
  def run_high_fidelity(inputs: PterasimInput) -> Optional[PterasimOutput]: """Execute a steady PteraSoftware solve and convert the results. Returns ``None`` if PteraSoftware is not installed. """ if ps is None: # pragma: no cover - guarded import return None try: airplane = _build_airplane(inputs) operating_point = ps.operating_point.OperatingPoint( # type: ignore[attr-defined] rho=inputs.air_density_kg_m3, vCg__E=max(inputs.cruise_velocity_m_s, 0.1), alpha=math.degrees(inputs.stroke_amplitude_rad), beta=0.0, ) problem = ps.problems.SteadyProblem( # type: ignore[attr-defined] airplanes=[airplane], operating_point=operating_point, ) solver = ps.steady_ring_vortex_lattice_method.SteadyRingVortexLatticeMethodSolver( # type: ignore[attr-defined] steady_problem=problem, ) solver.run(logging_level="Error") forces = solver.airplanes[0].forces_W # type: ignore[attr-defined] metadata = { "solver": "pterasoftware", "solver_version": getattr(ps, "__version__", "unknown"), "panel_count": int(solver.num_panels), } velocity = max(inputs.cruise_velocity_m_s, 0.1) rho = inputs.air_density_kg_m3 ref_area = inputs.planform_area_m2 omega = 2.0 * math.pi * inputs.stroke_frequency_hz aerodynamic_lift = float(-forces[2]) dynamic_pressure = 0.5 * rho * (velocity**2) aspect_ratio = inputs.span_m**2 / ref_area if ref_area > 0 else 0.0 target_cl = inputs.cl_alpha_per_rad * inputs.stroke_amplitude_rad induced_drag = float(-forces[0]) if aspect_ratio > 0 and dynamic_pressure > 0: induced_drag = max( dynamic_pressure * ref_area * (target_cl**2) / (math.pi * aspect_ratio * 0.9), 0.0, ) else: induced_drag = max(induced_drag, 0.0) parasitic_drag = 0.5 * rho * (velocity**2) * ref_area * inputs.cd0 thrust = induced_drag + parasitic_drag heave_lift = 0.5 * rho * ref_area * (omega * inputs.stroke_amplitude_rad) ** 2 lift = aerodynamic_lift + heave_lift moment_arm = ( inputs.tail_moment_arm_m if inputs.tail_moment_arm_m is not None else inputs.span_m / 4.0 ) torque = lift * moment_arm metadata.update( { "induced_drag_N": induced_drag, "parasitic_drag_N": parasitic_drag, "heave_lift_N": heave_lift, "aero_lift_N": aerodynamic_lift, } ) return PterasimOutput( thrust_N=thrust, lift_N=lift, torque_Nm=torque, metadata=metadata, )