Skip to main content

Step 6: Hands-On: Demo Run

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.

Prerequisites​

Before running the demo, verify these prerequisites are complete:

  • ✅ Motor IDs configured and tested (Steps 1, 3)
  • ✅ CAN interface configured (Step 2)
  • ✅ OpenArm CAN library built (Step 4)
  • ✅ Motor zero position set to safe values, baudrate matches CAN interface configuration (Step 5)
⚠️ 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:

./build/openarm-demo

Configure the Demo​

Configured with your specific motor setup by editing openarm_can/examples and rebuild 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);

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.

Rebuild the Demo​

After modifying the configuration, rebuild the demo:

cmake --build build --target openarm-demo

Run the Demo​

cd build
./openarm-demo

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
...

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.