Human demonstrations offer a scalable data source for dexterous manipulation, but transferring them to robot actions remains challenging due to the embodiment gap. Today's retargeting is mostly kinematic, yet manipulation is decided by force, which governs how the hand interacts with the object and how the object moves. In this paper, we present ReForce, a Force-aware Retargeting method that turns human motion and forces into robot actions that reproduce the intended contact. ReForce predicts a residual on the kinematically retargeted action to reach the desired force, using a general force tracker trained on large-scale simulation interactions. It supports both online force-aware teleoperation and offline data translation. In simulation and on real hardware, ReForce achieves lower force-tracking error and stronger multi-finger contact engagement on contact-rich tasks such as paper-cup grasping and tongs manipulation.
Figures & tables
Figure 1: Force-aware retargeting overview. Human-guided motion and contact references specify the intended interaction, while ReForce uses robot-side fingertip force feedback to adapt the reference into dexterous-hand commands during contact-rich execution.
Figure 2: ReForce training and inference pipeline. During training, randomized and augmented simulation interactions provide joint and force trajectories from which future-window motion and contact targets are constructed. During deployment, ReForce adapts references using online fingertip force feedback.
Figure 3: Human demonstration and robot execution setup. Teleoperation uses a Quest controller for wrist pose, a Manus glove for hand pose, and calibrated fingertip FSR sensors for human contact force. For ACT demonstration collection, a RealSense L515 camera tracks an AprilTag attached near the wrist, while the glove and FSR setup remains unchanged. A UFACTORY xArm equipped with an XHand executes the robot-side motion and provides fingertip tactile feedback.
Grasp
Replay
Admittance
ReForce
Side
0.309±0.006
0.280±0.013
0.247±0.036
Top
0.736±0.000
0.619±0.048
0.474±0.049
Table 1: Real-world paper cup grasping replay. Force-tracking error in Newtons, reported as mean ± standard deviation over five trials. Lower is better.
Figure 4: Qualitative comparison of execution behavior. Direct replay does not react to contact error, while admittance control uses a fixed force-to-motion mapping. ReForce learns contact-dependent command corrections from interaction data.
Task
Method
Force-safe success ↑
Tracking error ↓
Over-force ↓
Severe missing contact ↓
Active fingers ↑
Paper cup
Reference policy
30.0%
0.812
0/10
7/10
0.17
Paper cup
Reference policy + Admittance
60.0%
0.683
4/10
1/10
1.26
Paper cup
Reference policy + ReForce
70%
0.124
2/10
0/10
2.61
Tongs
Reference policy
50.0%
0.454
0/10
5/10
0.94
Tongs
Reference policy + Admittance
90.0%
0.419
0/10
1/10
1.34
Tongs
Reference policy + ReForce
54.5%
0.441
4/11
1/11
1.62
Table 2: Real-world execution with learned references. Force-safe success requires task completion, forces below the task-specific threshold, and no severe missing-contact failure. Tracking error is the mean absolute force error over time and fingertips, reported in Newtons.
Figure 7
Appendix figures & tables4 assets
Supplementary material from the paper’s appendix.
Appendix
Item
Value
Future-target horizon
Up to 16 future frames; joint and force targets are averaged over the available future window
Policy architecture
Per-finger MLP policy; the four non-thumb fingers use a shared [128,128] trunk with [64] finger-specific heads, while the thumb uses a separate [128,128] trunk and [64] head; ReLU activations
Joint-update limit
0.088 rad per controlled joint, approximately 5∘
Observation perturbations
Gaussian joint noise, Gaussian force noise with standard deviation 0.1 N, and per-finger force dropout with probability 0.30
Optimization
AdamW with learning rate 10−3 , weight decay 10−5 , batch size 1024 , 20 epochs, and 500 training steps per epoch
Appendix
Table 4: ReForce training configuration. Main hyperparameters used for the reported experiments.
Item
Value
Training data
Separate policy per task; approximately 30 – 40 human demonstrations per task
Temporal context
History length H=9 and prediction chunk length C=32
Sampling frequency
Raw demonstrations at 83 Hz; training anchors sampled at 10 Hz
Phase representation
Dϕ=3 , with ϕt=[τt,sin(2πτt),cos(2πτt)] , where τt=(t−1)/(T−1)
Force-loss weight
λF=1.0
Network architecture
Context MLP with widths [128,128,256] , followed by separate 2 -layer motion and force Transformer decoders with width 256 , 4 attention heads, feed-forward width 1024 , and dropout 0.1
Appendix
Table 5: ACT reference-policy training configuration. Main parameters used for the learned motion-and-force reference policies.
Figure 6: Force tracking under replayed references. Real-robot force trajectories for side and top paper-cup grasps using direct replay, admittance control, and ReForce . These curves correspond to the results in Table 4.1.1 .
Figure 7: Representative paper-cup force-tracking trials. Force trajectories produced by position replay, admittance control, and ReForce .