In this letter, subjects take part in a fruit picker game on the robot-assisted rehabilitation system RehabRoby. The difficulty level of the game is adjusted using three feedback strategies. We use the scores of the subjects as the first feedback to determine the difficulty level in score feedback adjustment (SFA). We then consider physiological feedback, which is the mean skin conductance of the subjects, in physiological feedback adjustment (PFA). Finally, we use both the score and mean skin conductance to determine the difficulty level in combined performance and physiological feedback adjustment (CFA). Subsequently, we seek to understand the subjects’ level of excitement by analyzing the subjective ratings using a survey, and by observing the statistically significant features generated from the collected physiological signals when they were performing the task using the proposed three feedback strategies. Survey results indicate that subjects respond positively to SFA and CFA but respond negatively to PFA because PFA proposes under-challenging levels to prevent a stressful experience, and as a result the subjects become bored. We find the skin conductance response ($SCR$), mean skin conductance ($Mean_{SC}$), heart rate ($HR$), inter-beat interval ($IBI$), and mean temperature ($Mean_{temp}$) as significant features between SFA, PFA, and CFA. The statistically significant features indicate that CFA proposes unpredictable difficulty levels, which keep the subjects more active, focused, and excited when compared to SFA and PFA.

中文翻译：

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在机器人辅助康复系统 RehabRoby 中基于分数和生理信号反馈的动态难度级别调整

在这封信中，受试者参加了机器人辅助康复系统 RehabRoby 上的水果采摘游戏。使用三种反馈策略调整游戏的难度级别。我们以受试者的分数作为第一反馈来确定分数反馈调整（SFA）的难度级别。然后，我们在生理反馈调整 (PFA) 中考虑生理反馈，即受试者的平均皮肤电导。最后，我们使用分数和平均皮肤电导来确定综合表现和生理反馈调整 (CFA) 的难度级别。随后，我们试图通过使用调查分析主观评分来了解受试者的兴奋程度，并通过使用建议的三种反馈策略观察收集的生理信号在执行任务时产生的统计显着特征。调查结果表明，受试者对 SFA 和 CFA 反应积极，但对 PFA 反应消极，因为 PFA 提出了挑战不足的水平以防止压力体验，结果受试者变得无聊。我们发现皮肤电导反应（$SCR$), 平均皮肤电导 ($Mean_{SC}$）， 心率 （$HR$), 节拍间隔 ($IBI$) 和平均温度 ($Mean_{temp}$) 作为 SFA、PFA 和 CFA 之间的显着特征。统计上的显着特征表明，与 SFA 和 PFA 相比，CFA 提出了不可预测的难度级别，使受试者更加活跃、专注和兴奋。