Files
RL-Sim-Framework/src/sysid/motor/export.py
2026-03-22 15:49:13 +01:00

187 lines
6.7 KiB
Python

"""Export tuned motor parameters to MJCF and robot.yaml files.
Reads the original motor.xml and robot.yaml, patches with optimised
parameter values, and writes motor_tuned.xml + robot_tuned.yaml.
Usage:
python -m src.sysid.motor.export \
--asset-path assets/motor \
--result assets/motor/motor_sysid_result.json
"""
from __future__ import annotations
import argparse
import copy
import json
import xml.etree.ElementTree as ET
from pathlib import Path
import structlog
import yaml
log = structlog.get_logger()
_DEFAULT_ASSET = "assets/motor"
def export_tuned_files(
asset_path: str | Path,
params: dict[str, float],
) -> tuple[Path, Path]:
"""Write tuned MJCF and robot.yaml files.
Returns (tuned_mjcf_path, tuned_robot_yaml_path).
"""
asset_path = Path(asset_path).resolve()
robot_yaml_path = asset_path / "robot.yaml"
robot_cfg = yaml.safe_load(robot_yaml_path.read_text())
mjcf_path = asset_path / robot_cfg["mjcf"]
# ── Tune MJCF ────────────────────────────────────────────────
tree = ET.parse(str(mjcf_path))
root = tree.getroot()
# Actuator — use average gear for the MJCF model.
gear_pos = params.get("actuator_gear_pos", params.get("actuator_gear"))
gear_neg = params.get("actuator_gear_neg", params.get("actuator_gear"))
gear_avg = None
if gear_pos is not None and gear_neg is not None:
gear_avg = (gear_pos + gear_neg) / 2.0
elif gear_pos is not None:
gear_avg = gear_pos
filter_tau = params.get("actuator_filter_tau")
for act_el in root.iter("general"):
if act_el.get("name") == "motor":
if gear_avg is not None:
act_el.set("gear", str(gear_avg))
if filter_tau is not None:
if filter_tau > 0:
act_el.set("dyntype", "filter")
act_el.set("dynprm", str(filter_tau))
else:
act_el.set("dyntype", "none")
# Joint — average damping & friction for MJCF (asymmetry in runtime).
fl_pos = params.get("motor_frictionloss_pos", params.get("motor_frictionloss"))
fl_neg = params.get("motor_frictionloss_neg", params.get("motor_frictionloss"))
fl_avg = None
if fl_pos is not None and fl_neg is not None:
fl_avg = (fl_pos + fl_neg) / 2.0
elif fl_pos is not None:
fl_avg = fl_pos
damp_pos = params.get("motor_damping_pos", params.get("motor_damping"))
damp_neg = params.get("motor_damping_neg", params.get("motor_damping"))
damp_avg = None
if damp_pos is not None and damp_neg is not None:
damp_avg = (damp_pos + damp_neg) / 2.0
elif damp_pos is not None:
damp_avg = damp_pos
for jnt in root.iter("joint"):
if jnt.get("name") == "motor_joint":
if damp_avg is not None:
jnt.set("damping", str(damp_avg))
if "motor_armature" in params:
jnt.set("armature", str(params["motor_armature"]))
if fl_avg is not None:
jnt.set("frictionloss", str(fl_avg))
# Rotor mass.
if "rotor_mass" in params:
for geom in root.iter("geom"):
if geom.get("name") == "rotor_disk":
geom.set("mass", str(params["rotor_mass"]))
# Write tuned MJCF.
tuned_mjcf_name = mjcf_path.stem + "_tuned" + mjcf_path.suffix
tuned_mjcf_path = asset_path / tuned_mjcf_name
ET.indent(tree, space=" ")
tree.write(str(tuned_mjcf_path), xml_declaration=True, encoding="unicode")
log.info("tuned_mjcf_written", path=str(tuned_mjcf_path))
# ── Tune robot.yaml ──────────────────────────────────────────
tuned_cfg = copy.deepcopy(robot_cfg)
tuned_cfg["mjcf"] = tuned_mjcf_name
if tuned_cfg.get("actuators") and len(tuned_cfg["actuators"]) > 0:
act = tuned_cfg["actuators"][0]
if gear_avg is not None:
act["gear"] = round(gear_avg, 6)
if "actuator_filter_tau" in params:
act["filter_tau"] = round(params["actuator_filter_tau"], 6)
if "motor_damping" in params:
act["damping"] = round(params["motor_damping"], 6)
if "joints" not in tuned_cfg:
tuned_cfg["joints"] = {}
if "motor_joint" not in tuned_cfg["joints"]:
tuned_cfg["joints"]["motor_joint"] = {}
mj = tuned_cfg["joints"]["motor_joint"]
if "motor_armature" in params:
mj["armature"] = round(params["motor_armature"], 6)
if fl_avg is not None:
mj["frictionloss"] = round(fl_avg, 6)
# Asymmetric / hardware-realism / nonlinear parameters.
realism = {}
for key in [
"actuator_gear_pos", "actuator_gear_neg",
"motor_damping_pos", "motor_damping_neg",
"motor_frictionloss_pos", "motor_frictionloss_neg",
"motor_deadzone_pos", "motor_deadzone_neg",
"action_bias",
"viscous_quadratic", "back_emf_gain",
"stribeck_friction_boost", "stribeck_vel",
"gearbox_backlash",
]:
if key in params:
realism[key] = round(params[key], 6)
if realism:
tuned_cfg["hardware_realism"] = realism
tuned_yaml_path = asset_path / "robot_tuned.yaml"
header = (
"# Tuned motor config — generated by src.sysid.motor.optimize\n"
"# Original: robot.yaml\n\n"
)
tuned_yaml_path.write_text(
header + yaml.dump(tuned_cfg, default_flow_style=False, sort_keys=False)
)
log.info("tuned_robot_yaml_written", path=str(tuned_yaml_path))
return tuned_mjcf_path, tuned_yaml_path
# ── CLI ──────────────────────────────────────────────────────────────
def main() -> None:
parser = argparse.ArgumentParser(
description="Export tuned motor parameters to MJCF + robot.yaml."
)
parser.add_argument("--asset-path", type=str, default=_DEFAULT_ASSET)
parser.add_argument(
"--result", type=str, default=None,
help="Path to motor_sysid_result.json (auto-detected if omitted)",
)
args = parser.parse_args()
asset_path = Path(args.asset_path).resolve()
if args.result:
result_path = Path(args.result)
else:
result_path = asset_path / "motor_sysid_result.json"
if not result_path.exists():
raise FileNotFoundError(f"Result file not found: {result_path}")
result = json.loads(result_path.read_text())
params = result["best_params"]
export_tuned_files(asset_path=args.asset_path, params=params)
if __name__ == "__main__":
main()