mangavalkandClaude Opus 5.5
91dac16fca
Not yet verified on hardware. - shared/HexapodProtocol: CmdPacket (now 20 bytes, adds remote_roll / remote_pitch), FLAG_* bits and radio settings as the single protocol definition; static payload size = sizeof(CmdPacket) on both radios. - robot: use the shared protocol; vx = forward (harness w/x <-> q/e); InputMapper adds remote tilt on top of the right stick when FLAG_REMOTE_GYRO is set, and robot.ino no longer zeroes stick roll/pitch when it's off. - remote (Teensy 4.1): Sticks (calibration, EEPROM), RemoteIMU, RemoteState (interlocks, link-loss disarm, smoothing), PacketBuilder, RadioLink, NextionUI, SerialConsole. - CLAUDE.md, README.md, remote/README.md, remote/NEXTION.md. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
133 lines
6.6 KiB
Markdown
133 lines
6.6 KiB
Markdown
# Hexapod robot firmware (Teensy 4.0)
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This is the **robot-side** firmware. It is fully functional on its own
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(driven by the serial test harness below) and receives commands from the
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remote (`../remote/`) over nRF24L01. The packet format lives in
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`../shared/HexapodProtocol/HexapodProtocol.h` — the single definition both
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sketches compile against.
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## Building
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From the repo root (PlatformIO): `pio run -e robot`, flash with
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`pio run -e robot -t upload`, monitor with `pio device monitor -e robot`.
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RF24 is pulled in automatically via `lib_deps`; Servo ships with the Teensy
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framework.
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Arduino IDE also works if you copy `shared/HexapodProtocol/` into your
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sketchbook `libraries/` folder and install **RF24** by TMRh20.
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## Before you trust this on the floor
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Everything in `Config.h` is a placeholder for a generic small hexapod. Measure
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your own robot and edit:
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- `LEG_MOUNT_ANGLE_DEG` / `LEG_MOUNT_X_MM` / `LEG_MOUNT_Y_MM` — where each
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coxa pivot actually sits on your chassis, and which way it points
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- `COXA_LEN_MM` / `FEMUR_LEN_MM` / `TIBIA_LEN_MM` — your link lengths
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- `COXA_MIN_DEG..TIBIA_MAX_DEG` — your servos' real safe range of motion
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- `STANCE_RADIUS_MM` / `STANCE_HEIGHT_MM` — how far out/down you want the
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resting foot position
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- `SERVO_PINS` — must be PWM-capable pins on your Teensy 4.0 wiring
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- `SERVO_US_AT_0DEG` / `SERVO_US_PER_DEG` — calibrate per servo, they vary
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batch to batch
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- `RADIO_CE_PIN` / `RADIO_CSN_PIN` — your nRF24 wiring. Address, channel,
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data rate, PA level and payload size are in `shared/HexapodProtocol` so
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they can't drift from the remote.
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- **Pin conflict:** `SERVO_PINS` leg 3 uses pins 11 and 12, which are the
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Teensy 4.0's SPI MOSI/MISO that the nRF24 needs. Move those two servos
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before wiring the radio.
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## Bench-check checklist (do this before the first stand-up)
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These are sign conventions that depend on which way your hardware is
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physically mounted, and the code has a best-guess default that may be wrong
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for your build:
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1. **IK elbow/tibia direction** (`Kinematics.cpp`) — command one leg to a
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few known foot positions by hand (e.g. via the serial harness) and watch
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whether the knee bends the way you expect. Flip the sign noted in the
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comment on `tibia_rad` if it bends backwards.
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2. **BodyPose roll/pitch sign** (`BodyPose.cpp`) — command a small roll/pitch
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offset and verify the body leans the direction you asked for, not the
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opposite.
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3. **RobotIMU register map** (`RobotIMU.cpp`) — written for an MPU6050-style
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chip (I2C addr `0x68`). If your gyro is a different part, its register
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addresses and scale factors will differ; swap them in.
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4. **Sit-pose assumption** — the built-in sit pose in `robot.ino` assumes all
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six feet stay grounded and simply lowers the body (a 0.4x height blend).
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If your chassis is meant to rest its belly on the ground instead, this
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needs a different, sequenced approach (fold legs up rather than just
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lowering).
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5. **Gait travel direction** (`GaitEngine.cpp`) — the protocol defines
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`+vx` = forward, `+vy` = left, `+yaw_rate` = turn left (CCW). As written,
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the stance phase sweeps each foot from `neutral - half_stride` to
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`neutral + half_stride`, i.e. the foot moves *with* the commanded
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direction, which pushes the body the opposite way. Verify with `w` on the
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bench; if the robot backs up, swap `start`/`end` in `GaitEngine::update`
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(fixes translation and yaw together). The `z`/`c` harness keys were
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written against the current behavior — recheck them after that fix.
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## Testing without a remote yet
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`robot.ino` has `#define TEST_SERIAL_INPUT` enabled by default. With that on,
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open the Arduino Serial Monitor (115200 baud, no line ending needed — single
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keystrokes) and use:
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| Key | Action |
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|-----|--------|
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| `a` | toggle armed |
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| `s` | toggle sit / stand |
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| `w` / `x` | walk forward / backward (`vx` ±) |
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| `q` / `e` | strafe left / right (`vy` ±) |
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| `z` / `c` | yaw left / right |
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| `g` | toggle gait: tripod ↔ wave |
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| `m` | toggle walk mode: direct (A) ↔ heading-hold (B) |
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| space | zero all velocity (stop walking, stay in current state) |
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Each keystroke injects a `CmdPacket` through `Comms::injectPacket()` — the
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exact same path a real remote's received radio packets go through, so the
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rest of the pipeline (mapper → state machine → gait → pose → IK → servos)
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runs identically to how it will with real hardware. Once you have a real
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remote transmitting, just remove the `#define TEST_SERIAL_INPUT` line (or
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leave it — injected packets simply won't happen if you don't type).
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Arm (`a`), then stand (`s`), before trying to walk — the state machine
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enforces `DISARMED → SIT → STAND → WALKING` in order and will otherwise
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ignore walk commands.
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## Link with the remote
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- `CmdPacket` and the `FLAG_*` bits in `shared/HexapodProtocol` are the
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exact wire format. Both radios set a static payload size of
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`sizeof(CmdPacket)`, so a robot and remote built from different protocol
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versions won't receive each other at all (and the robot fails safe).
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- Failsafe: if no packet arrives for `LINK_TIMEOUT_SEC`, `Comms::linkOk()`
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goes false and the main loop falls back to a zeroed `CmdPacket`, which
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disarms the robot.
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- The right stick's roll/pitch/yaw (or X/Y/Z) always apply. The remote's
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handset tilt arrives in its own `remote_roll` / `remote_pitch` fields and
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is added on top only while `FLAG_REMOTE_GYRO` is set, capped at
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`MAX_TILT_DEG` total (`InputMapper`). `FLAG_ROBOT_GYRO` independently
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enables the robot's own IMU stabilization.
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- `FLAG_RSTICK_XLATE` switches the right stick between rotation-axes and
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translation-axes interpretation, and `FLAG_MODE_B` switches between the
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two walk modes, all inside the existing `InputMapper`.
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## File layout
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```
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robot/
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├── robot.ino - main sketch: setup/loop, state wiring, serial test harness
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├── Config.h - all placeholder constants (edit this first)
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├── SmoothedValue.h - generic rate-limited setpoint smoother
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├── Kinematics.h/.cpp - per-leg 3-DOF analytical IK
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├── GaitEngine.h/.cpp - tripod/wave gait, per-leg phase, dynamic gait swap
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├── BodyPose.h/.cpp - 6-axis body pose composition (feedforward + IMU correction)
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├── RobotIMU.h/.cpp - gyro/accel read + complementary filter
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├── StateMachine.h/.cpp - DISARMED/SIT/STAND/WALKING with smoothed sit-stand blend
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├── InputMapper.h/.cpp - CmdPacket -> twist/pose/mode decoding
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├── Limits.h/.cpp - workspace clamp, joint rate limit, stance polygon check
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├── Comms.h/.cpp - nRF24L01 receive (packet definition is in shared/HexapodProtocol)
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└── ServoDriver.h/.cpp - servo attach/relax/write
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```
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