Quadratic Programming-based Reference Spreading Control for Dual-Arm Robotic Manipulation with Planned Simultaneous Impacts

TL;DR

This work addresses tracking control for dual-arm manipulation with nominally simultaneous impacts using an extended reference spreading (RS) framework. It introduces a quadratic programming (QP)-based RS controller with ante-, interim-, and post-impact modes, where the interim mode blends references and reduces velocity feedback to handle uncertainty in contact timing. A teleoperation-based method generates impact-consistent references that enable low-gain, stable demonstrations feeding autonomous RS control; experiments on two 7-DOF Franka arms with silicone end effectors validate robustness to environmental uncertainty and show reduced input peaks compared with baselines. The approach provides a practical route to exploit impacts in manipulation tasks, achieving faster, more reliable grasping under variable contact conditions, with potential extensions to autonomous planning and formal stability analysis.

Abstract

With the aim of further enabling the exploitation of intentional impacts in robotic manipulation, a control framework is presented that directly tackles the challenges posed by tracking control of robotic manipulators that are tasked to perform nominally simultaneous impacts. This framework is an extension of the reference spreading control framework, in which overlapping ante- and post-impact references that are consistent with impact dynamics are defined. In this work, such a reference is constructed starting from a teleoperation-based approach. By using the corresponding ante- and post-impact control modes in the scope of a quadratic programming control approach, peaking of the velocity error and control inputs due to impacts is avoided while maintaining high tracking performance. With the inclusion of a novel interim mode, we aim to also avoid input peaks and steps when uncertainty in the environment causes a series of unplanned single impacts to occur rather than the planned simultaneous impact. This work in particular presents for the first time an experimental evaluation of reference spreading control on a robotic setup, showcasing its robustness against uncertainty in the environment compared to three baseline control approaches.

Figures (11)

• Figure 1: Depiction of the dual-arm robotic setup used for experimental validation of the presented control approach.
• Figure 2: Depiction of the teleoperation procedure, where a user uses the VIVE handheld controller devices to prescribe a reference for both end effectors.
• Figure 3: Visualization of the robot control scheme based on QP robot control employed for recording a reference through teleoperation. All physical entities are red, the controller-related signals are blue, and the recorded signals are black.
• Figure 4: Snapshots of the system during reference recording procedure.
• Figure 5: Depiction of the recorded position, velocity and force signals around the impact time in $y$-direction, i.e. the direction normal to the impact surface, together with the extended ante- and post-impact references. The black dashed lines indicates the recorded impact time $T_r$ together with the time interval of exclusion $\Delta T_r$.