Add real robot devices and scripts to control real robot (#288)

Co-authored-by: Simon Alibert <alibert.sim@gmail.com>

tests/test_motors.py

@@ -0,0 +1,92 @@
+import time
+
+import numpy as np
+import pytest
+
+from lerobot.common.robot_devices.utils import RobotDeviceAlreadyConnectedError, RobotDeviceNotConnectedError
+from tests.utils import require_koch
+
+
+@require_koch
+def test_motors_bus(request):
+    # TODO(rcadene): measure fps in nightly?
+    # TODO(rcadene): test logs
+    # TODO(rcadene): test calibration
+    # TODO(rcadene): add compatibility with other motors bus
+    from lerobot.common.robot_devices.motors.dynamixel import DynamixelMotorsBus
+
+    # Test instantiating a common motors structure.
+    # Here the one from Alexander Koch follower arm.
+    port = "/dev/tty.usbmodem575E0032081"
+    motors = {
+        # name: (index, model)
+        "shoulder_pan": (1, "xl430-w250"),
+        "shoulder_lift": (2, "xl430-w250"),
+        "elbow_flex": (3, "xl330-m288"),
+        "wrist_flex": (4, "xl330-m288"),
+        "wrist_roll": (5, "xl330-m288"),
+        "gripper": (6, "xl330-m288"),
+    }
+    motors_bus = DynamixelMotorsBus(port, motors)
+
+    # Test reading and writting before connecting raises an error
+    with pytest.raises(RobotDeviceNotConnectedError):
+        motors_bus.read("Torque_Enable")
+    with pytest.raises(RobotDeviceNotConnectedError):
+        motors_bus.write("Torque_Enable", 1)
+    with pytest.raises(RobotDeviceNotConnectedError):
+        motors_bus.disconnect()
+
+    # Test deleting the object without connecting first
+    del motors_bus
+
+    # Test connecting
+    motors_bus = DynamixelMotorsBus(port, motors)
+    motors_bus.connect()
+
+    # Test connecting twice raises an error
+    with pytest.raises(RobotDeviceAlreadyConnectedError):
+        motors_bus.connect()
+
+    # Test disabling torque and reading torque on all motors
+    motors_bus.write("Torque_Enable", 0)
+    values = motors_bus.read("Torque_Enable")
+    assert isinstance(values, np.ndarray)
+    assert len(values) == len(motors)
+    assert (values == 0).all()
+
+    # Test writing torque on a specific motor
+    motors_bus.write("Torque_Enable", 1, "gripper")
+
+    # Test reading torque from this specific motor. It is now 1
+    values = motors_bus.read("Torque_Enable", "gripper")
+    assert len(values) == 1
+    assert values[0] == 1
+
+    # Test reading torque from all motors. It is 1 for the specific motor,
+    # and 0 on the others.
+    values = motors_bus.read("Torque_Enable")
+    gripper_index = motors_bus.motor_names.index("gripper")
+    assert values[gripper_index] == 1
+    assert values.sum() == 1  # gripper is the only motor to have torque 1
+
+    # Test writing torque on all motors and it is 1 for all.
+    motors_bus.write("Torque_Enable", 1)
+    values = motors_bus.read("Torque_Enable")
+    assert (values == 1).all()
+
+    # Test ordering the motors to move slightly (+1 value among 4096) and this move
+    # can be executed and seen by the motor position sensor
+    values = motors_bus.read("Present_Position")
+    motors_bus.write("Goal_Position", values + 1)
+    # Give time for the motors to move to the goal position
+    time.sleep(1)
+    new_values = motors_bus.read("Present_Position")
+    assert (new_values == values).all()
+
+
+@require_koch
+def test_find_port(request):
+    from lerobot.common.robot_devices.motors.dynamixel import find_port
+
+    find_port()