351 lines
14 KiB
Python
351 lines
14 KiB
Python
"""Logic to calibrate a robot arm built with feetech motors"""
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# TODO(rcadene, aliberts): move this logic into the robot code when refactoring
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import time
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import numpy as np
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from lerobot.common.robot_devices.motors.feetech import (
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CalibrationMode,
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TorqueMode,
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convert_degrees_to_steps,
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)
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from lerobot.common.robot_devices.motors.utils import MotorsBus
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URL_TEMPLATE = (
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"https://raw.githubusercontent.com/huggingface/lerobot/main/media/{robot}/{arm}_{position}.webp"
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)
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# The following positions are provided in nominal degree range ]-180, +180[
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# For more info on these constants, see comments in the code where they get used.
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ZERO_POSITION_DEGREE = 0
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ROTATED_POSITION_DEGREE = 90
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def assert_drive_mode(drive_mode):
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# `drive_mode` is in [0,1] with 0 means original rotation direction for the motor, and 1 means inverted.
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if not np.all(np.isin(drive_mode, [0, 1])):
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raise ValueError(f"`drive_mode` contains values other than 0 or 1: ({drive_mode})")
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def apply_drive_mode(position, drive_mode):
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assert_drive_mode(drive_mode)
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# Convert `drive_mode` from [0, 1] with 0 indicates original rotation direction and 1 inverted,
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# to [-1, 1] with 1 indicates original rotation direction and -1 inverted.
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signed_drive_mode = -(drive_mode * 2 - 1)
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position *= signed_drive_mode
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return position
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def compute_nearest_rounded_position(position, models):
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# delta_turn = convert_degrees_to_steps(ROTATED_POSITION_DEGREE, models)
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# nearest_pos = np.round(position.astype(float) / delta_turn) * delta_turn
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# return nearest_pos.astype(position.dtype)
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return position
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def move_until_block(arm, motor_name, positive_direction=True, while_move_hook=None):
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count = 0
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while True:
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present_pos = arm.read("Present_Position", motor_name)
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if positive_direction:
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arm.write("Goal_Position", present_pos + 100, motor_name)
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else:
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arm.write("Goal_Position", present_pos - 100, motor_name)
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if while_move_hook is not None:
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while_move_hook()
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present_pos = arm.read("Present_Position", motor_name).item()
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present_speed = arm.read("Present_Speed", motor_name).item()
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present_load = arm.read("Present_Load", motor_name).item()
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# present_voltage = arm.read("Present_Voltage", motor_name).item()
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# present_temperature = arm.read("Present_Temperature", motor_name).item()
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# print(f"{present_pos=}")
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# print(f"{present_speed=}")
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# print(f"{present_load=}")
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# print(f"{present_voltage=}")
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# print(f"{present_temperature=}")
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if present_load > 100 and present_speed == 0:
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count += 1
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if count > 100:
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return present_pos
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else:
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count = 0
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def move_to_calibrate(arm, motor_name, positive_first=True, in_between_move_hook=None, while_move_hook=None):
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initial_pos = arm.read("Present_Position", motor_name)
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if positive_first:
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p_present_pos = move_until_block(
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arm, motor_name, positive_direction=True, while_move_hook=while_move_hook
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)
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p_delta_pos = abs(initial_pos - p_present_pos)
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if in_between_move_hook is not None:
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in_between_move_hook()
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n_present_pos = move_until_block(
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arm, motor_name, positive_direction=False, while_move_hook=while_move_hook
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)
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n_delta_pos = abs(initial_pos - n_present_pos)
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else:
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n_present_pos = move_until_block(
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arm, motor_name, positive_direction=False, while_move_hook=while_move_hook
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)
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n_delta_pos = abs(initial_pos - n_present_pos)
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if in_between_move_hook is not None:
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in_between_move_hook()
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p_present_pos = move_until_block(
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arm, motor_name, positive_direction=True, while_move_hook=while_move_hook
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)
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p_delta_pos = abs(initial_pos - p_present_pos)
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if p_delta_pos < n_delta_pos:
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invert_drive_mode = False
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min_pos = n_present_pos
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max_pos = p_present_pos
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zero_pos = (min_pos + max_pos) / 2
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homing_offset = -zero_pos
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else:
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invert_drive_mode = True
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min_pos = p_present_pos
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max_pos = n_present_pos
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zero_pos = (min_pos + max_pos) / 2
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homing_offset = zero_pos
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calib_data = {
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"homing_offset": homing_offset,
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"invert_drive_mode": invert_drive_mode,
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"drive_mode": -1 if invert_drive_mode else 0,
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"zero_pos": zero_pos,
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"min_pos": min_pos,
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"max_pos": max_pos,
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}
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return calib_data
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def apply_offset(calib, offset):
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calib["zero_pos"] += offset
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if calib["drive_mode"]:
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calib["homing_offset"] += offset
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else:
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calib["homing_offset"] -= offset
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return calib
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def run_arm_auto_calibration(arm: MotorsBus, robot_type: str, arm_name: str, arm_type: str):
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if (arm.read("Torque_Enable") != TorqueMode.DISABLED.value).any():
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raise ValueError("To run calibration, the torque must be disabled on all motors.")
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print(f"\nRunning calibration of {robot_type} {arm_name} {arm_type}...")
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print("\nMove arm to initial position")
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print("See: " + URL_TEMPLATE.format(robot=robot_type, arm=arm_type, position="initial"))
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input("Press Enter to continue...")
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arm.write("Lock", 0)
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arm.write("Acceleration", 10)
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time.sleep(1)
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arm.write("Torque_Enable", TorqueMode.ENABLED.value)
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calib = {}
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# Calibrate shoulder_pan
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calib["shoulder_pan"] = move_to_calibrate(arm, "shoulder_pan")
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arm.write("Goal_Position", calib["shoulder_pan"]["zero_pos"], "shoulder_pan")
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time.sleep(1)
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# Calibrate elbow_flex
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calib["elbow_flex"] = move_to_calibrate(arm, "elbow_flex")
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calib["elbow_flex"] = apply_offset(calib["elbow_flex"], offset=130 - 1024)
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arm.write("Goal_Position", calib["elbow_flex"]["zero_pos"] + 1024, "elbow_flex")
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time.sleep(1)
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# Calibrate wrist_flex
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calib["wrist_flex"] = move_to_calibrate(arm, "wrist_flex")
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calib["wrist_flex"] = apply_offset(calib["wrist_flex"], offset=100)
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arm.write("Goal_Position", calib["wrist_flex"]["zero_pos"], "wrist_flex")
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time.sleep(1)
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# Calibrate gripper
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calib["gripper"] = move_to_calibrate(arm, "gripper")
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tmp_max_pos = calib["gripper"]["max_pos"]
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calib["gripper"]["max_pos"] = calib["gripper"]["min_pos"]
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calib["gripper"]["min_pos"] = tmp_max_pos
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arm.write("Goal_Position", calib["gripper"]["min_pos"], "gripper")
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time.sleep(1)
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arm.write("Goal_Position", calib["wrist_flex"]["zero_pos"] - 1350, "wrist_flex")
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time.sleep(1)
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# Calibrate shoulder_lift
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def in_between_move_hook():
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nonlocal arm, calib
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initial_pos = arm.read("Present_Position", "shoulder_lift")
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arm.write("Goal_Position", initial_pos + 900, "shoulder_lift")
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time.sleep(1)
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arm.write("Goal_Position", calib["elbow_flex"]["zero_pos"] - 150, "elbow_flex")
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time.sleep(1)
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calib["shoulder_lift"] = move_to_calibrate(
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arm, "shoulder_lift", positive_first=False, in_between_move_hook=in_between_move_hook
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)
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# add an 30 steps as offset to align with body
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calib["shoulder_lift"] = apply_offset(calib["shoulder_lift"], offset=30 + 1024 - 120)
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# Calibrate wrist_roll
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def while_move_hook():
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nonlocal arm, calib
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positions = {
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"shoulder_lift": round(calib["shoulder_lift"]["zero_pos"] - 1600),
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"elbow_flex": round(calib["elbow_flex"]["zero_pos"] + 1700),
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"wrist_flex": round(calib["wrist_flex"]["zero_pos"] + 800),
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"gripper": round(calib["gripper"]["max_pos"] - 400),
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}
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arm.write("Goal_Position", list(positions.values()), list(positions.keys()))
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arm.write("Goal_Position", round(calib["shoulder_lift"]["zero_pos"] - 1600), "shoulder_lift")
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time.sleep(2)
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arm.write("Goal_Position", round(calib["elbow_flex"]["zero_pos"] + 1700), "elbow_flex")
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time.sleep(2)
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arm.write("Goal_Position", round(calib["wrist_flex"]["zero_pos"] + 800), "wrist_flex")
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time.sleep(2)
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arm.write("Goal_Position", round(calib["gripper"]["max_pos"] - 400), "gripper")
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time.sleep(2)
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calib["wrist_roll"] = move_to_calibrate(
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arm, "wrist_roll", positive_first=False, while_move_hook=while_move_hook
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)
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arm.write("Goal_Position", calib["wrist_roll"]["zero_pos"], "wrist_roll")
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time.sleep(1)
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arm.write("Goal_Position", calib["gripper"]["min_pos"], "gripper")
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time.sleep(1)
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arm.write("Goal_Position", calib["wrist_flex"]["zero_pos"], "wrist_flex")
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time.sleep(1)
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arm.write("Goal_Position", calib["elbow_flex"]["zero_pos"] + 2048, "elbow_flex")
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arm.write("Goal_Position", calib["shoulder_lift"]["zero_pos"] - 2048, "shoulder_lift")
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time.sleep(1)
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arm.write("Goal_Position", calib["shoulder_pan"]["zero_pos"], "shoulder_pan")
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time.sleep(1)
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calib_modes = []
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for name in arm.motor_names:
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if name == "gripper":
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calib_modes.append(CalibrationMode.LINEAR.name)
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else:
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calib_modes.append(CalibrationMode.DEGREE.name)
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calib_dict = {
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"homing_offset": [calib[name]["homing_offset"] for name in arm.motor_names],
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"drive_mode": [calib[name]["drive_mode"] for name in arm.motor_names],
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"start_pos": [calib[name]["min_pos"] for name in arm.motor_names],
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"end_pos": [calib[name]["max_pos"] for name in arm.motor_names],
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"calib_mode": calib_modes,
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"motor_names": arm.motor_names,
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}
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return calib_dict
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def run_arm_manual_calibration(arm: MotorsBus, robot_type: str, arm_name: str, arm_type: str):
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"""This function ensures that a neural network trained on data collected on a given robot
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can work on another robot. For instance before calibration, setting a same goal position
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for each motor of two different robots will get two very different positions. But after calibration,
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the two robots will move to the same position.To this end, this function computes the homing offset
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and the drive mode for each motor of a given robot.
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Homing offset is used to shift the motor position to a ]-2048, +2048[ nominal range (when the motor uses 2048 steps
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to complete a half a turn). This range is set around an arbitrary "zero position" corresponding to all motor positions
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being 0. During the calibration process, you will need to manually move the robot to this "zero position".
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Drive mode is used to invert the rotation direction of the motor. This is useful when some motors have been assembled
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in the opposite orientation for some robots. During the calibration process, you will need to manually move the robot
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to the "rotated position".
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After calibration, the homing offsets and drive modes are stored in a cache.
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Example of usage:
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```python
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run_arm_calibration(arm, "koch", "left", "follower")
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```
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"""
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if (arm.read("Torque_Enable") != TorqueMode.DISABLED.value).any():
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raise ValueError("To run calibration, the torque must be disabled on all motors.")
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print(f"\nRunning calibration of {robot_type} {arm_name} {arm_type}...")
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print("\nMove arm to zero position")
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print("See: " + URL_TEMPLATE.format(robot=robot_type, arm=arm_type, position="zero"))
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input("Press Enter to continue...")
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# We arbitrarily chose our zero target position to be a straight horizontal position with gripper upwards and closed.
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# It is easy to identify and all motors are in a "quarter turn" position. Once calibration is done, this position will
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# correspond to every motor angle being 0. If you set all 0 as Goal Position, the arm will move in this position.
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zero_target_pos = convert_degrees_to_steps(ZERO_POSITION_DEGREE, arm.motor_models)
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# Compute homing offset so that `present_position + homing_offset ~= target_position`.
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zero_pos = arm.read("Present_Position")
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homing_offset = zero_target_pos - zero_pos
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# The rotated target position corresponds to a rotation of a quarter turn from the zero position.
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# This allows to identify the rotation direction of each motor.
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# For instance, if the motor rotates 90 degree, and its value is -90 after applying the homing offset, then we know its rotation direction
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# is inverted. However, for the calibration being successful, we need everyone to follow the same target position.
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# Sometimes, there is only one possible rotation direction. For instance, if the gripper is closed, there is only one direction which
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# corresponds to opening the gripper. When the rotation direction is ambiguous, we arbitrarely rotate clockwise from the point of view
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# of the previous motor in the kinetic chain.
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print("\nMove arm to rotated target position")
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print("See: " + URL_TEMPLATE.format(robot=robot_type, arm=arm_type, position="rotated"))
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input("Press Enter to continue...")
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rotated_target_pos = convert_degrees_to_steps(ROTATED_POSITION_DEGREE, arm.motor_models)
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# Find drive mode by rotating each motor by a quarter of a turn.
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# Drive mode indicates if the motor rotation direction should be inverted (=1) or not (=0).
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rotated_pos = arm.read("Present_Position")
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drive_mode = (rotated_pos < zero_pos).astype(np.int32)
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# Re-compute homing offset to take into account drive mode
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rotated_drived_pos = apply_drive_mode(rotated_pos, drive_mode)
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homing_offset = rotated_target_pos - rotated_drived_pos
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print("\nMove arm to rest position")
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print("See: " + URL_TEMPLATE.format(robot=robot_type, arm=arm_type, position="rest"))
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input("Press Enter to continue...")
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print()
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# Joints with rotational motions are expressed in degrees in nominal range of [-180, 180]
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calib_modes = []
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for name in arm.motor_names:
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if name == "gripper":
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calib_modes.append(CalibrationMode.LINEAR.name)
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else:
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calib_modes.append(CalibrationMode.DEGREE.name)
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calib_data = {
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"homing_offset": homing_offset.tolist(),
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"drive_mode": drive_mode.tolist(),
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"start_pos": zero_pos.tolist(),
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"end_pos": rotated_pos.tolist(),
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"calib_mode": calib_modes,
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"motor_names": arm.motor_names,
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}
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return calib_data
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