FT sensor data is increasing continously and not changing even after giving external force #3054

akinfinity21 · 2026-01-27T12:04:19Z

akinfinity21
Jan 27, 2026

Intro

Hi!

my name is akash , I use MuJoCo for my research project in my college

My setup

import time
import mujoco
import numpy as np

model = mujoco.MjModel.from_xml_path(
"/home/akash/ros2_ws/src/doosan-robot2/dsr_description2/mujoco_models/a0509/a0509.xml"
)
data = mujoco.MjData(model)

🔹 Flush all previous data

mujoco.mj_resetData(model, data)
mujoco.mj_forward(model, data)

print("Starting FT logging from clean state...\n")

while True:
mujoco.mj_step(model, data)

# Copy sensor data AFTER step
ft = data.sensordata.copy()

force  = ft[0:3]
torque = ft[3:6]

print(f"Force : {force}")
print(f"Torque: {torque}\n")

time.sleep(model.opt.timestep)

My question

i am unable to get the correct FT sensor value. the sensor value keeps on increasing even though the robot remains at ideal position. the robot FT sensor gives correct value when open in mujoco viewer but act different when i launch through ros launch file.

Minimal model and/or code that explain my question

<material name="blue" rgba="0.227 0.251 0.31 1"/>
<material name="metal" rgba="0.65 0.65 0.65 1"/>
<material name="sky_blue" rgba="0.016 0.933 0.992 1.0"/>

<geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_0_0" material="metal"/>
<body name="link_1" pos="0 0 0.1560">
  <inertial pos="-6.9e-05 0.024423 -0.007375" quat="0.626042 0.779776 -0.00329495 0.00321293" mass="3.715" diaginertia="0.0189902 0.017021 0.0135698"/>
  <joint name="joint_1" pos="0 0 0" axis="0 0 1" range="-6.2832 6.2832" actuatorfrcrange="-194 194" damping="800"/>
  <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_1_0" material="metal"/>
  <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_1_1" material="blue"/>
  <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_1_2" material="sky_blue"/>
  <body name="link_2" quat="0.499898 -0.500102 -0.5 -0.5">
    <inertial pos="0.20449 0 0.13271" quat="0.499405 0.500811 0.499197 0.500585" mass="6.837" diaginertia="0.25627 0.25442 0.019399"/>
    <joint name="joint_2" pos="0 0 0" axis="0 0 1" range="-6.2832 6.2832" actuatorfrcrange="-194 194" damping="800"/>
    <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_2_0" material="blue"/>
    <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_2_1" material="blue"/>
    <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_2_2" material="blue"/>
    <body name="link_3" pos="0.409 0 0" quat="0.707035 0 0 0.707179">
      <inertial pos="7.1e-05 -0.005123 0.033009" quat="0.704152 -0.0338098 0.031631 0.708538" mass="2.769" diaginertia="0.013912 0.012526 0.00877466"/>
      <joint name="joint_3" pos="0 0 0" axis="0 0 1" range="-2.7925 2.7925" actuatorfrcrange="-163 163" damping="800"/>
      <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_3_0" material="metal"/>
      <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_3_1" material="blue"/>
      <body name="link_4" pos="0 -0.367 0" quat="0.707035 0.707179 0 0">
        <inertial pos="-8.6e-05 0.086348 -0.086031" quat="0.983575 -0.180483 0.000213119 0.00238692" mass="2.679" diaginertia="0.0560681 0.0528175 0.00763342"/>
        <joint name="joint_4" pos="0 0 0" axis="0 0 1" range="-6.2832 6.2832" actuatorfrcrange="-50 50" damping="600"/>
        <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_4_0" material="blue"/>
        <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_4_1" material="blue"/>
        <body name="link_5" quat="0.707035 -0.707179 0 0">
          <inertial pos="9.1e-05 -0.006457 0.015434" quat="0.480275 0.522032 -0.522242 0.473372" mass="2.051" diaginertia="0.0104696 0.00907878 0.00845556"/>
          <joint name="joint_5" pos="0 0 0" axis="0 0 1" range="-6.2832 6.2832" actuatorfrcrange="-50 50" damping="600"/>
          <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_5_0" material="metal"/>
          <geom type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_5_1" material="blue"/>
          <body name="link_6" pos="0 -0.124 0" quat="0.707035 0.707179 0 0">
            <inertial pos="-2.2e-05 -7e-06 -0.051746" quat="0.999989 0.00141825 -0.000201627 0.0044558" mass="0.773" diaginertia="0.00874837 0.00785656 0.00444517"/>
            <joint name="joint_6" pos="0 0 0" axis="0 0 1" range="-6.2832 6.2832" actuatorfrcrange="-50 50" damping="600"/>
            <site name="ft_site_joint6" pos="0 0 0" size="0.01" rgba="0 1 0 1"/>
            <geom name="link6_geom" type="mesh" contype="1" conaffinity="1" group="1" density="0" mesh="A0509_6_0" material="metal"/>
            <geom name="link6_collision" type="capsule" fromto="0 0 0  0 0 0.12" size="0.03" contype="1" conaffinity="1" density="1000" rgba="1 0 0 0.3"/>
          </body>
        </body>
      </body>
    </body>
  </body>
</body>

   <actuator>
	<position name="joint_1" joint="joint_1" kp="10" kv="1" ctrlrange="-3.14 3.14"/>
	<position name="joint_2" joint="joint_2" kp="10" kv="1" ctrlrange="-3.14 3.14"/>
	<position name="joint_3" joint="joint_3" kp="10" kv="1" ctrlrange="-3.14 3.14"/>
	<position name="joint_4" joint="joint_4" kp="10" kv="1" ctrlrange="-3.14 3.14"/>
	<position name="joint_5" joint="joint_5" kp="10" kv="1" ctrlrange="-3.14 3.14"/>
	<position name="joint_6" joint="joint_6" kp="10" kv="1" ctrlrange="-3.14 3.14"/>
</actuator>

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FT sensor data is increasing continously and not changing even after giving external force #3054

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FT sensor data is increasing continously and not changing even after giving external force #3054

Uh oh!

akinfinity21 Jan 27, 2026

Intro

My setup

🔹 Flush all previous data

My question

Minimal model and/or code that explain my question

Confirmations

Replies: 0 comments

akinfinity21
Jan 27, 2026