This Rust library controls DJI RoboMaster motors over a Linux SocketCAN interface.
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GM6020 "current" is actually "torque current", which is the portion of current in-phase with the voltage, i.e. how much current is generating useful torque. So while you command 1.62A, keep in mind the motor could be drawing over 3A.
The velocity and torque commands are simply voltage and current commands scaled by constants given in the datasheets. These may not be accurate across the full range of running conditions. For better accuracy or position control your controller must utilize feedback from get_state - or consider using the PWM interface.
M3508 and M2006 only accept Current commands. The Voltage/Velocity numbers above are for reference only.
Switching from Voltage/Velocity to Current/Torque modes requires changing parameters in RoboMaster Assistant.
Temperature is only reported in whole-number precision.
This library provides a C/C++ wrapper over rm_motors_can. Static and dynamic libraries are created in the target directory and header files are generated in the include directory. A neat way to include this in your C++ program is to use Corrosion, which will automatically build the Rust crate and create a CMake target to link against.
Unfortunately the C header does not contain "fully-qualified" names. Ideally each name would be prefixed with rm_motors_can_ to avoid conflict of common names like init. There is some ongoing work in the cbindgen tool to address this. If it is an issue for your project, change the function names in Rust and uncomment the [export] block in cbindgen_c.toml to prefix all other items.
ROS 2 wrapper which enables advanced control interfaces such as ros2_control and MoveIt. Talk about layers of abstraction! This repo has an example hardware setup and CMakeLists.txt.
The motor should be accessible via a SocketCAN interface. This can be accomplished with a USB CAN adapter, Raspberry Pi HAT, or built-in CAN interface like on an NVIDIA Orin. Don't forget to power the motor with 24V, configure CAN termination resistors, and set the motor ID; from the factory the ID is 0, which is invalid for GM6020. GM6020 ID 1-4 cannot coexist with M3508/M2006 ID 5-8 due to overlapping CAN Bus addresses.
TODO building stalls at the cargo expand step when not in --release mode.
cargo install cargo-expand
cargo build --release
By default the examples connect to a motor on can0 with ID 1. They command the motor in voltage mode and display velocity values.
These choices are set as constants at the top of the examples and may need to be changed to work with your system.
cd rm_motors_can
cargo run --release --example rm_motors_can_test
cargo run --release --example rm_motors_can_test_cpp
When the datasheet says "Use black for GND, grey for TX, and white for PWM/RX", it means white is the RX pin of the motor and should be connected to the TX pin of your serial adapter. The adapter should be set for 5V logic levels. Only start RM Assistant AFTER the motor has booted up, otherwise it will not connect. You don't have to click anything on the blue waiting screen; it will automatically detect the motor after a few seconds. Click to open the motor and in the bottom left there is a language selector. After changing parameters you must click the "Settings" button in the bottom right to apply them. The "enable current ring" parameter switches between Voltage/Velocity and Current/Torque control modes.