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Step 5: Hands-On: Demo Run

info

Prerequisites: Before running the demo, verify these prerequisites are complete:

  • ✅ Motor IDs configured and tested (Steps 1, 3)
  • ✅ CAN interface configured (Step 2)
  • ✅ Motor zero position set to safe values, baudrate matches CAN interface configuration (Step 4)

Now that your basic communication is working, let's run the full OpenArm demo program to test complete system functionality. More details for control can be found here.

⚠️ READ BEFORE RUNNING DEMO ⚠️
  • ZERO POSITION: Ensure you have set safe zero positions for all motors
  • EMERGENCY STOP: Keep emergency stop button within immediate reach at ALL times
  • CLEAR WORKSPACE: Remove ALL obstacles, tools, and personnel from arm movement area
  • POWER DISCONNECT: Know how to quickly disconnect power if needed

Failure to follow these safety requirements may result in serious injury or equipment damage.

Connect the motors in a daisy-chain using XT30 2+2 cables. See detailed wiring instructions →

The default demo uses motors 0x01, 0x02, 0x07 (DM4310) on CAN0 with CANFD. If your setup matches, run directly:

openarm-can-demo

What the Demo Does​

The demo program performs these operations:

  1. Initialization: Sets up CAN interface and motor communication
  2. Motor Query: Reads and displays motor IDs to verify configuration
  3. Motor Control:
    • Enables all motors
    • Performs position control tests
    • Performs torque control tests
  4. Gripper Control: Opens and closes the gripper (if configured)
  5. Status Monitoring: Displays motor positions for 10 cycles
  6. Cleanup: Safely disables all motors

Modify the configuration as needed for your setup.

Expected Output​

You should see output similar to:

=== OpenArm CAN Example ===
This example demonstrates the OpenArm API functionality
Initializing OpenArm CAN...
Initializing gripper...

=== Enabling Motors ===

=== Querying Motor Recv IDs ===
Arm Motor: 1 ID: 17
Arm Motor: 2 ID: 18
Gripper Motor: 8 ID: 24

=== Controlling Motors ===
Closing gripper...
Arm Motor: 1 position: 0.123
Arm Motor: 2 position: 0.456
Gripper Motor: 8 position: 0.789
...

Configure the Demo​

Prerequisites​

Before proceeding, ensure you have the required system:

Download the CAN Library​

wget https://github.com/enactic/openarm_can/releases/download/1.2.2/openarm-can-1.2.2.tar.gz
tar xf openarm-can-1.2.2.tar.gz
cd openarm-can-1.2.2

Configure the Demo​

Configured with your specific motor setup by editing examples/demo.cpp and build if needed. Find and update these sections to match your motor setup:

// Initialize arm motors
std::vector<openarm::damiao_motor::MotorType> motor_types = {
    openarm::damiao_motor::MotorType::DM4310,
    openarm::damiao_motor::MotorType::DM4310
};
std::vector<uint32_t> send_can_ids = {0x01, 0x02};  // Your motor send IDs
std::vector<uint32_t> recv_can_ids = {0x11, 0x12};  // Your motor receive IDs

Example configurations:

7-motor arm:

std::vector<openarm::damiao_motor::MotorType> motor_types = {
    openarm::damiao_motor::MotorType::DM8009,
    openarm::damiao_motor::MotorType::DM8009,
    openarm::damiao_motor::MotorType::DM4340,
    openarm::damiao_motor::MotorType::DM4340,
    openarm::damiao_motor::MotorType::DM4310,
    openarm::damiao_motor::MotorType::DM4310,
    openarm::damiao_motor::MotorType::DM4310
};
std::vector<uint32_t> send_can_ids = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};
std::vector<uint32_t> recv_can_ids = {0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17};
warning

Ensure all three vectors (motor_types, send_can_ids, recv_can_ids) have the same length to avoid undefined behavior.

gripper

If you have a gripper, update the gripper configuration. Otherwise, remove all code using the gripper.

// Initialize gripper
openarm.init_gripper_motor(openarm::damiao_motor::MotorType::DM4310, 0x08, 0x18);

Build the Demo​

After modifying the configuration, build the demo:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --target openarm-can-demo

Run the Demo​

build/openarm-can-demo

Troubleshooting​

  • Use candump to monitor CAN communication
  • Verify motor power supply (24V)
  • Check cable connections (especially for daisy-chained setups)

What's Next​

Congrats! You have completed the basic setup. If the demo runs successfully, you can now develop custom applications using the OpenArm API or try ROS2 integration.

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