Joint Group Control

set_group_cmd()

Python

set_group_cmd(
    position_cmd: Dict[str, list[float]],
    velocity_cmd: Dict[str, list[float]] | None = None,
    torque_cmd: Dict[str, list[float]] | None = None
)

Sends position, velocity, and torque commands to one or more joint groups. position_cmd is required; the others are optional. Commands take effect immediately — interpolation is recommended to avoid sudden jumps.

Parameter	Type	Description
position_cmd	Dict[str, list[float]]	group name → target joint position list (rad)
velocity_cmd	Dict[str, list[float]] | None	group name → target joint velocity list (rad/s)
torque_cmd	Dict[str, list[float]] | None	group name → target joint torque list (Nm)

Valid group names (depends on robot model; refer to hardware.json):

waist (5 DOF), head (2 DOF), left_manipulator (7 DOF), right_manipulator (7 DOF), left_end_effector, right_end_effector

The two end effectors can be used as raw command targets and expose a one-dimensional state via get_group_state(); however, get_group_motion_state() and get_group_motor_cfg() currently support only waist, head, left_manipulator, and right_manipulator — do not pass left_end_effector or right_end_effector to them.

danger

Waist commands must contain five joint values. Its safe default position is [-1.25, 2.15, -0.918, 0, 0]; never command all waist joints to zero.

Example: upper-body control with interpolation

Targets are generated from "current reading + bounded offset" instead of hardcoded absolute poses (joint zero positions are not fixed; keep single-joint offsets within ±0.03 rad). Joint commands must be streamed continuously in state 4 (upper_body_tele_task):

Python

import os
import time

os.environ.setdefault("FASTDDS_BUILTIN_TRANSPORTS", "UDPv4")  # required on the robot

from fourier_aurora_client import AuroraClient

client = AuroraClient.get_instance(domain_id=123, robot_name="grw")
try:
    time.sleep(1.0)
    if not client.set_fsm_state(4):
        raise RuntimeError("state change request not accepted")
    deadline = time.monotonic() + 4.0
    while client.get_fsm_state() != 4:
        if time.monotonic() >= deadline:
            raise RuntimeError("did not switch to upper_body_tele_task")
        time.sleep(0.05)

    init_pose = client.get_group_state("left_manipulator", key="position")
    target_pose = list(init_pose)
    target_pose[0] += 0.03
    steps = 200

    for i in range(steps + 1):                    # move to target
        pose = [s + (t - s) * i / steps for s, t in zip(init_pose, target_pose)]
        client.set_group_cmd({"left_manipulator": pose})
        time.sleep(0.01)
    for i in range(steps + 1):                    # return to start
        pose = [t + (s - t) * i / steps for s, t in zip(init_pose, target_pose)]
        client.set_group_cmd({"left_manipulator": pose})
        time.sleep(0.01)
finally:
    if client.get_fsm_state() == 4:
        client.set_fsm_state(3)                   # back to the standing policy state
    client.close()

---

get_group_state()

Python

get_group_state(group_name: str, key: str = 'position') -> list[float]

Reads the current state of a specified joint group.

Parameter	Type	Description
group_name	str	Joint group name
key	str	Data type to return — see table below

key value	Description
'position'	Joint positions (rad), default
'velocity'	Joint velocities (rad/s)
'effort'	Joint torques (Nm)

Example

Python

import os
import time

os.environ.setdefault("FASTDDS_BUILTIN_TRANSPORTS", "UDPv4")  # required on the robot

from fourier_aurora_client import AuroraClient

client = AuroraClient.get_instance(domain_id=123, robot_name="grw")
try:
    time.sleep(1.0)  # wait for state data
    pos = client.get_group_state("waist", key="position")
    vel = client.get_group_state("waist", key="velocity")
    print(f"waist position: {pos}")
    print(f"waist velocity: {vel}")
finally:
    client.close()

---

get_group_motion_state()

Python

get_group_motion_state(group_name: str) -> int

Reads the current motion state of a specified joint group.

Return value	Description
0	Idle
1	Moving
2	Stopping
3	Error

GR-W limitation

While interpolation commands are streamed at 100 Hz in state 4, the motion state of left_manipulator stays 0 (idle). The return value does not reflect motion caused by teleoperation commands and must not be used to wait for "motion complete"; rely on the end of the command stream and convergence of get_group_state() positions instead.

Example

Python

import os
import time

os.environ.setdefault("FASTDDS_BUILTIN_TRANSPORTS", "UDPv4")  # required on the robot

from fourier_aurora_client import AuroraClient

client = AuroraClient.get_instance(domain_id=123, robot_name="grw")
try:
    time.sleep(1.0)  # wait for state data
    state = client.get_group_motion_state("left_manipulator")
    print(f"motion state: {state} (0=idle)")
finally:
    client.close()