295efa2d83
End-to-end implementation per docs/sprint-2-plan.md.
Builds: pio run -e esp32-dev SUCCESS, RAM 6.8%, Flash 26.8% (351 KB).
Tests: pytest 129/129 green (110 Sprint 1 + 19 Sprint 2).
Python (arautopilot/studio/simulator/):
- rudder_dynamics.py: marine-realistic physical model of a hydraulic
rudder actuator. Defaults tuned so 100 % PWM produces steady-state
v_max ~5 deg/s, matching the brief's "typical 3-6 dps" for a 30 m
yacht. Includes deadband, min-useful PWM snap, port/stbd asymmetry,
end-stops, optional external torque, RunRecorder helper.
- pid_inner.py: pure-Python reference PID. Anti-windup via back-
calculation, setpoint rate limit, setpoint deadband, derivative LPF,
actuator non-linearity compensation. This module is the algorithmic
source of truth; C++ firmware is a line-by-line port.
Firmware (firmware/ar_autopilot_v1/src/pid/):
- pid_inner.h: header-only C++17 controller, byte-equivalent port of
pid_inner.py. Compiles on ESP32 toolchain AND on host g++/clang/MSVC
(no Arduino dependencies) -- ready for native Unity cross-validation
once a host compiler is installed.
- pid_inner_task.{h,cpp}: FreeRTOS task wrapper. 50 Hz on Core 1
(real-time core). Subscribes to TWDT, bleeds integrator during
STANDBY, surfaces telemetry + tunables via the Modbus slave.
Modbus map (regenerated from YAML):
- 6 new INPUT registers (40-45): setpoint, output, error, kp/ki/kd live
- 4 new HOLDING registers (16-19): writable setpoint + kp/ki/kd req
(writes propagate atomically; zero kp rejected as ILLEGAL_DATA_VALUE)
Tests:
- test_rudder_simulator.py: 9 tests (zero-input rest, full deflection,
end-stop saturation, deadband, min-useful snap, asymmetry, recorder
API, invalid dt, end-stop velocity zeroing).
- test_pid_inner_python.py: 10 tests (positive/negative step response,
setpoint deadband holds, anti-windup bounds under saturation,
allowed=false bleeds integrator, actuator deadband + asymmetry
compensation, output saturation, rate limit, disturbance rejection).
NOT in Sprint 2 (intentional per brief sec. 12):
- Outer heading PID, gain scheduling by SOG, ROT feed-forward
(those land in Sprint 3)
- Cross-validation tests via ctypes (need host C++ compiler that
this Windows machine lacks; algorithmic parity enforced by review)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
46 lines
1.7 KiB
C++
46 lines
1.7 KiB
C++
// =============================================================================
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// pid_inner_task.h -- 50 Hz inner-loop control task (Sprint 2)
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// =============================================================================
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//
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// Wraps the header-only PidInner controller in a FreeRTOS task pinned to
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// Core 1 (real-time core). Reads the rudder position from hal::rudder_sensor,
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// consumes the setpoint that the outer loop / Modbus client wrote, and
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// commands hal::rudder_actuator. Refuses to act in STANDBY or with master
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// power off (those interlocks live in hal::rudder_command itself).
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// =============================================================================
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#pragma once
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#include "pid_inner.h"
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namespace arautopilot::pid {
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/// Initialise the controller with the seed gains. Must be called from
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/// setup() once.
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void pid_inner_task_init();
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/// Spawn the FreeRTOS task. Must be called after pid_inner_task_init().
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void pid_inner_task_start();
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/// Update the setpoint that the inner loop pursues. Called by the Modbus
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/// slave (when an operator writes a holding register) and, later, by the
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/// outer loop task. Units: degrees, signed.
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void pid_inner_set_setpoint_deg(float setpoint_deg);
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/// Read the current setpoint (thread-safe).
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float pid_inner_setpoint_deg();
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/// Read the latest PID output command (signed PWM percent).
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float pid_inner_last_output_pct();
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/// Read the latest error (deg) the controller saw.
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float pid_inner_last_error_deg();
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/// Hot-swap gains at runtime (thread-safe).
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void pid_inner_update_gains(float kp, float ki, float kd);
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/// Read the gains currently in use.
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void pid_inner_get_gains(float& kp, float& ki, float& kd);
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} // namespace arautopilot::pid
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