Behavior--Realization Separation for Constrained Physical Human--Robot Interaction

arXiv:2609.00669v1 Announce Type: new Abstract: Physical human--robot interaction software often couples desired-behavior specification with constrained realization; we treat these as separate layers. A behavior layer supplies a desired contact-port acceleration a_k^{id}=f_heta(e_k,ot e_k,F_{h,k}). A realization layer converts it into constrained robot commands and reports total desired-versus-realized acceleration error instead of hiding it in saturation. A same-objective unconstrained counterfactual separates regularization from constraint intervention, while plant data expose model error. This paper implements a receding-horizon quadratic program realizing memoryless affine behaviors. Changing the behavior modifies objective coefficients through (C_heta,G_heta) while the robot-command variable and feasible set remain unchanged. A planar study instantiates impedance and admittance; the same running layer accepts an impedance--admittance--impedance reassignment without reconstruction, under its existing rate limit. On a torque-controlled 7-DOF Franka FR3 in MuJoCo, the runtime freezes task-space dynamics per solve and enforces torque feasibility across its horizon. Under a sustained 20~~N push, it holds a slack-relaxed workspace boundary to within approximately 0.1--0.2~~mm, versus 4.4~~cm (impedance) and 4.7~~cm (admittance) overshoot from instantaneous clipping. A derated actuator budget then activates the torque constraint: horizon-wide enforcement keeps its frozen-model plan feasible to 2.1imes10^{-4}~~Ndotm, whereas a first-step-only ablation plans up to 11.329~~Ndotm beyond budget; on the executed nonlinear plant, where both share the same local-model error, the gap is smaller but still favors horizon-wide enforcement (0.161 vs. 0.380~Ndotm). These results are a focused proof of behavior--realization separation.

Source: arXiv cs.RO | 2026-09-02

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