akars

Rust rewrite entry point for AKA-00 hardware control on SG2002.

Implemented scope:

• USB camera capture from /dev/cvi-usb-camera0 using the StarryOS ioctl protocol.
• MJPEG decode and letterbox preprocessing through a pure Rust image pipeline.
• YOLOv8 CVI runtime inference and postprocess from aka-sg2002/detect.*.
• UART motor protocol from aka-rk3588/motor/uart_motor_driver.*.
• ZP10D arm UART protocol from aka-rk3588/arm.
• Tennis chasing and grab state machine from aka-sg2002/tennis.cpp.

AKA-00/demo and shell scripts are intentionally not rewritten here.

Host builds compile the pure Rust pieces and use a TPU stub. SG2002 builds link only the TPU SDK runtime libraries for riscv64gc-unknown-linux-musl.

Build for SG2002:

cd akars
scripts/setup.sh
scripts/build.sh

scripts/setup.sh installs the Rust target, initializes the TPU SDK submodule, downloads the Xuantie V3.4.0 musl toolchain, verifies its SHA-256, and extracts it to toolchains/xuantie-v3.4.0. The TPU SDK lives at toolchains/tpu-sdk-sg200x as a git submodule.

For an offline setup, provide the toolchain archive explicitly:

scripts/setup.sh --archive /path/to/Xuantie-900-gcc-linux-6.6.36-musl64-x86_64-V3.4.0-20260323.tar.gz

Override local paths when needed:

AKARS_TOOLCHAIN_DIR=/path/to/xuantie-v3.4.0 \
AKARS_TPU_SDK_DIR=/path/to/tpu-sdk-sg200x \
scripts/build.sh

Build facts:

• Target: riscv64gc-unknown-linux-musl. The AKA-00 board runs a musl rootfs, not glibc and not bare-metal -none-elf.
• Rust uses the prebuilt target std; nightly and -Zbuild-std are not needed.
• .cargo/config.toml disables static CRT and requests the board loader: /lib/ld-musl-riscv64v0p7_xthead.so.1.
• scripts/linker.sh uses the Xuantie V3.4.0 GCC driver directly; its GNU ld links current Rust output successfully.

The output binary is target/riscv64gc-unknown-linux-musl/release/akars. On the device it needs libcviruntime.so, libcvikernel.so, and the matching libstdc++.so.6 reachable via LD_LIBRARY_PATH.

Upload the binary to a rootfs partition device, for example an SD card second partition:

scripts/upload.sh /dev/sda2

Run on device:

./akars /path/to/yolo_model.cvimodel \
  --camera /dev/cvi-usb-camera0 \
  --motor /dev/ttyS3 \
  --arm /dev/ttyS2

Useful options:

• --frames N: stop after N frames for smoke tests.
• --conf X: confidence threshold, default 0.5.
• --iou X: NMS IOU threshold, default 0.5.
• --classes N: class count, default 1.

Test TPU inference on a single image:

./akars detect /path/to/yolo_model.cvimodel input.jpg --out result.jpg

Runs the model on input.jpg, prints each detection (class, score, box), and writes result.jpg with the boxes drawn. Same --classes / --conf / --iou options as above; --out defaults to detect_out.jpg. Useful for verifying the model and runtime independently of the camera and motors.

Web control:

./akars serve \
  --listen 0.0.0.0:8080 \
  --motor /dev/ttyS3 \
  --arm /dev/ttyS2

Open http://<device-ip>:8080/ to control the base and arm from the built-in frontend. Use --mock to run the same frontend/backend on a development machine without AKA hardware.