Objective. Supplemental sensory feedback for myoelectric prostheses can provide both psychosocial and functional benefits during prosthesis control. However, the impact of feedback depends on multiple factors and there is insufficient understanding about the fundamental role of such feedback in prosthesis use. The framework of human motor control enables us to systematically investigate the user-prosthesis control loop. In this study, we explore how different task objectives such as speed and accuracy shape the control policy developed by participants in a prosthesis force-matching task. Approach. Participants were randomly assigned to two groups that both used identical electromyography control interface and prosthesis force feedback, through vibrotactile stimulation, to perform a prosthesis force-matching task. However, the groups received different task objectives specifying speed and accuracy demands. We then investigated the control policies developed by the participants. To this end, we not only evaluated how successful or fast participants were but also analyzed the behavioral strategies adopted by the participants to obtain such performance gains. Main results. First, we observed that participants successfully integrated supplemental prosthesis force feedback to develop both feedforward and feedback control policies, as demanded by the task objectives. We then observed that participants who first developed a (slow) feedback policy were quickly able to adapt their policy to more stringent speed demands, by switching to a combined feedforward-feedback control strategy. However, the participants who first developed a (fast) feedforward policy were not able to change their control policy and adjust to greater accuracy demands. Significance. Overall, the results signify how the framework of human motor control can be applied to study the role of feedback in user-prosthesis interaction. The results also reveal the utility of training prosthesis users to integrate supplemental feedback into their state estimation by designing training protocols that encourage the development of combined feedforward and feedback policy.

客观的。肌电假体的补充感觉反馈可以在假体控制过程中提供心理社会和功能方面的益处。然而，反馈的影响取决于多种因素，并且对这种反馈在假肢使用中的基本作用的认识不足。人体运动控制框架使我们能够系统地研究用户假肢控制回路。在这项研究中，我们探讨了不同的任务目标（例如速度和准确性）如何影响假肢力匹配任务中参与者制定的控制策略。方法。参与者被随机分配到两组，均使用相同的肌电图控制界面和假肢力反馈，通过振动触觉刺激，执行假肢力匹配任务。然而，这些小组收到了不同的任务目标，指定了速度和准确性要求。然后我们调查了参与者制定的控制政策。为此，我们不仅评估了参与者的成功或快速程度，还分析了参与者为获得此类绩效提升而采取的行为策略。主要结果。首先，我们观察到参与者成功地整合了补充假肢力反馈，以根据任务目标的要求制定前馈和反馈控制策略。然后我们观察到，通过切换到前馈-反馈组合控制策略，首先制定（慢）反馈策略的参与者能够迅速调整他们的策略以适应更严格的速度要求。然而，最初制定（快速）前馈策略的参与者无法改变他们的控制策略并适应更高的精度要求。意义。总体而言，结果表明人类运动控制框架如何应用于研究反馈在用户-假肢交互中的作用。结果还揭示了训练假肢用户通过设计鼓励开发组合前馈和反馈策略的训练协议将补充反馈集成到他们的状态估计中的效用。