We address a state-of-the-art reinforcement learning(RL)control approach to automatically configure robotic pros-thesis impedance parameters to enable end-to-end,continuous locomotion intended for transfemoral amputee...We address a state-of-the-art reinforcement learning(RL)control approach to automatically configure robotic pros-thesis impedance parameters to enable end-to-end,continuous locomotion intended for transfemoral amputee subjects.Specifically,our actor-critic based RL provides tracking control of a robotic knee prosthesis to mimic the intact knee profile.This is a significant advance from our previous RL based automatic tuning of prosthesis control parameters which have centered on regulation control with a designer prescribed robotic knee profile as the target.In addition to presenting the tracking control algorithm based on direct heuristic dynamic programming(dHDP),we provide a control performance guarantee including the case of constrained inputs.We show that our proposed tracking control possesses several important properties,such as weight convergence of the learning networks,Bellman(sub)optimality of the cost-to-go value function and control input,and practical stability of the human-robot system.We further provide a systematic simulation of the proposed tracking control using a realistic human-robot system simulator,the OpenSim,to emulate how the dHDP enables level ground walking,walking on different terrains and at different paces.These results show that our proposed dHDP based tracking control is not only theoretically suitable,but also practically useful.展开更多
<strong>Background:</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"> Intraoperative surgical planning tools (ISPTs) used in curren...<strong>Background:</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"> Intraoperative surgical planning tools (ISPTs) used in current-generation robotic arm-assisted total knee arthroplasty (RTKA) systems (such as Navio</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;"> and MAKO</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;">) involve employment of postoperative passive joint balancing. This results in improper ligament tension, which may negatively impact joint stability, which, in turn, may adversely affect patient function after TKA. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> A simulation-enhanced ISPT (SEISPT) that provides insights relating to postoperative active joint mechanics was developed. This involved four steps: 1) validation of a multi-body musculoskeletal model;2) optimization of the validated model;3) use of the validated and optimized model to derive knee performance equations (KPEs), which are equations that relate implant component characteristics to implant component biomechanical responses;and 4) optimization of the KPEs with respect to these responses. In a proof-of-concept study, KPEs that involved two</span></span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">com</span><span style="font-family:Verdana;">- </span><span style="font-family:;" "=""><span style="font-family:Verdana;">ponent biomechanical responses that have been shown to strongly correlate with poor proprioception (a common patient complaint post-TKA) were used to calculate optimal positions and orientations of the femoral and tibial components in the TKA design implanted in one subject (as reported in a publicly-available dataset). </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> The differences between the calculated implant positions and orientations and the corresponding achieved values for the implant components in the subject were not similar to component position and orientation errors reported in biomechanical literature studies involving Navio</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;"> and MAKO</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;">. Also, we indicate how SEISPT could be incorporated into the surgical workflow of Navio</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;"> with minimal disruption and increase in cost. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> SEISPT is a plausible alternative to current-gen</span></span><span style="font-family:Verdana;">- </span><span style="font-family:Verdana;">eration ISPTs.</span>展开更多
BACKGROUND De-afferentation or non-weight bearing induces rapid cortical and spinalα-motor neuron excitability.Author supposed that an end-effector type gait robot(EEGR)could provide patients with a training conditio...BACKGROUND De-afferentation or non-weight bearing induces rapid cortical and spinalα-motor neuron excitability.Author supposed that an end-effector type gait robot(EEGR)could provide patients with a training condition that was specific enough to activate rapid cortical/spinal neuroplasticity,leading to immediate muscle strengthening.The electromyographic and biomechanical comparisons were conducted.AIM To compare the electromyographic activities of the thigh and shank muscles and isometric peak torque(PT)before and after walking training on a floor or in the end-effector gait robot.METHODS Twelve outpatients without ambulatory dysfunction were recruited.Order of two interventions(5-min training on a floor at a comfortable pace or training in an EEGR with non-weight bearing on their feet and 100%guidance force at 2.1 km/h)were randomly chosen.Isometric PT,maximal ratio of torque development,amplitude of compound motor action potential(CMAP),and area under the curve(AUC)were evaluated before and 10 min after both interventions.RESULTS The degree of PT improvement of the dominant knee flexors was larger in the EEGR than on the floor(9.6±22.4 Nm/BW,P<0.01).The EEGR-trained patients had greater PT improvement of the dominant knee extensors than those who trained on the floor(4.5±28.1 Nm/BW,P<0.01).However,all electromyographic activities of the thigh and shank muscles(peak CMAP,mean and peak AUC)were significantly lower for the use of the EEGR than walking on the floor.CONCLUSION Immediate strengthening of the knee flexors and extensors was induced after the 5-min EEGR training,despite reduced muscular use.展开更多
背景:目前用于全膝关节置换的机器人系统设计的基本原理是将三维手术规划、术中危险区预警、实时数据反馈及机械臂辅助截骨等技术相结合,以实现全膝关节置换的精准化、个性化,这也恰好是它最大优势所在,因此近年来成为关节外科领域热点...背景:目前用于全膝关节置换的机器人系统设计的基本原理是将三维手术规划、术中危险区预警、实时数据反馈及机械臂辅助截骨等技术相结合,以实现全膝关节置换的精准化、个性化,这也恰好是它最大优势所在,因此近年来成为关节外科领域热点话题,备受关注。目的:文章将从机器人辅助全膝关节置换在关节外科领域的发展现状及其与传统全膝关节置换优劣势对比进行概述,此外,还将对机器人辅助全膝关节置换技术未来的发展进行展望。方法:应用计算机检索PubMed、中国知网、万方和维普数据库的相关文章,英文检索词:“robot OR robotic OR robotics OR robotically OR computer,total knee arthroplasty OR total knee replacement,TKA OR TKR”,中文检索词:“机器人辅助,计算机导航,全膝关节置换术”,最终纳入64篇文献进行综述分析。结果与结论:①用于辅助全膝关节置换的机器人系统根据其自由度分为主动式、半主动式和被动式。半主动式系统是目前使用最为广泛的机器人系统,该系统有效提高了全膝关节置换手术的精准性和个性化程度,但其高昂的使用成本与较长的学习曲线仍是在该领域内推广时需要权衡的主要因素。②机器人辅助全膝关节置换可实现膝关节局部三维空间的精准截骨、正确安置假体,已被广泛证明可以提供更好的假体植入精准度,减少影像学异常值,在术中可获得良好的软组织平衡,最终改善术后膝关节运动及功能状态。③但目前的机器人辅助系统依然存在客观的不足之处,包括不同机器人设备与术者之间的学习曲线问题、额外增加的安装和维护成本以及与机器人手术相关的潜在并发症,所以其能否让医疗系统及患者真正受益仍需要更长期的研究予以证明,机器人辅助系统也仍需进行更多实质性的改进。④机器人辅助全膝关节置换技术在临床上仍然处于初步研究阶段,并没有大范围地应用到临床,更加明确该技术的用法、完善该技术的临床操作规范和安全性成为了未来对该技术的研究侧重点。展开更多
基金This work was partly supported by the National Science Foundation(1563921,1808752,1563454,1808898).
文摘We address a state-of-the-art reinforcement learning(RL)control approach to automatically configure robotic pros-thesis impedance parameters to enable end-to-end,continuous locomotion intended for transfemoral amputee subjects.Specifically,our actor-critic based RL provides tracking control of a robotic knee prosthesis to mimic the intact knee profile.This is a significant advance from our previous RL based automatic tuning of prosthesis control parameters which have centered on regulation control with a designer prescribed robotic knee profile as the target.In addition to presenting the tracking control algorithm based on direct heuristic dynamic programming(dHDP),we provide a control performance guarantee including the case of constrained inputs.We show that our proposed tracking control possesses several important properties,such as weight convergence of the learning networks,Bellman(sub)optimality of the cost-to-go value function and control input,and practical stability of the human-robot system.We further provide a systematic simulation of the proposed tracking control using a realistic human-robot system simulator,the OpenSim,to emulate how the dHDP enables level ground walking,walking on different terrains and at different paces.These results show that our proposed dHDP based tracking control is not only theoretically suitable,but also practically useful.
文摘<strong>Background:</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"> Intraoperative surgical planning tools (ISPTs) used in current-generation robotic arm-assisted total knee arthroplasty (RTKA) systems (such as Navio</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;"> and MAKO</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;">) involve employment of postoperative passive joint balancing. This results in improper ligament tension, which may negatively impact joint stability, which, in turn, may adversely affect patient function after TKA. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> A simulation-enhanced ISPT (SEISPT) that provides insights relating to postoperative active joint mechanics was developed. This involved four steps: 1) validation of a multi-body musculoskeletal model;2) optimization of the validated model;3) use of the validated and optimized model to derive knee performance equations (KPEs), which are equations that relate implant component characteristics to implant component biomechanical responses;and 4) optimization of the KPEs with respect to these responses. In a proof-of-concept study, KPEs that involved two</span></span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">com</span><span style="font-family:Verdana;">- </span><span style="font-family:;" "=""><span style="font-family:Verdana;">ponent biomechanical responses that have been shown to strongly correlate with poor proprioception (a common patient complaint post-TKA) were used to calculate optimal positions and orientations of the femoral and tibial components in the TKA design implanted in one subject (as reported in a publicly-available dataset). </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> The differences between the calculated implant positions and orientations and the corresponding achieved values for the implant components in the subject were not similar to component position and orientation errors reported in biomechanical literature studies involving Navio</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;"> and MAKO</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;">. Also, we indicate how SEISPT could be incorporated into the surgical workflow of Navio</span><sup><span style="font-size:12px;font-family:Verdana;"><span lang="ZH-CN" style="font-size:12pt;font-family:宋体;">®</span></span></sup><span style="font-family:Verdana;"> with minimal disruption and increase in cost. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> SEISPT is a plausible alternative to current-gen</span></span><span style="font-family:Verdana;">- </span><span style="font-family:Verdana;">eration ISPTs.</span>
基金Supported by the Research Project of Future Growth Engine Flagship Project,No:CN16040)by Minister of Science,ICT and Future Planningthe National Research Foundation of Korea grant funded by the Korea government(Ministry of Science,ICT and Future Planning),No.NRF-2017R1A2B4011478
文摘BACKGROUND De-afferentation or non-weight bearing induces rapid cortical and spinalα-motor neuron excitability.Author supposed that an end-effector type gait robot(EEGR)could provide patients with a training condition that was specific enough to activate rapid cortical/spinal neuroplasticity,leading to immediate muscle strengthening.The electromyographic and biomechanical comparisons were conducted.AIM To compare the electromyographic activities of the thigh and shank muscles and isometric peak torque(PT)before and after walking training on a floor or in the end-effector gait robot.METHODS Twelve outpatients without ambulatory dysfunction were recruited.Order of two interventions(5-min training on a floor at a comfortable pace or training in an EEGR with non-weight bearing on their feet and 100%guidance force at 2.1 km/h)were randomly chosen.Isometric PT,maximal ratio of torque development,amplitude of compound motor action potential(CMAP),and area under the curve(AUC)were evaluated before and 10 min after both interventions.RESULTS The degree of PT improvement of the dominant knee flexors was larger in the EEGR than on the floor(9.6±22.4 Nm/BW,P<0.01).The EEGR-trained patients had greater PT improvement of the dominant knee extensors than those who trained on the floor(4.5±28.1 Nm/BW,P<0.01).However,all electromyographic activities of the thigh and shank muscles(peak CMAP,mean and peak AUC)were significantly lower for the use of the EEGR than walking on the floor.CONCLUSION Immediate strengthening of the knee flexors and extensors was induced after the 5-min EEGR training,despite reduced muscular use.
文摘背景:目前用于全膝关节置换的机器人系统设计的基本原理是将三维手术规划、术中危险区预警、实时数据反馈及机械臂辅助截骨等技术相结合,以实现全膝关节置换的精准化、个性化,这也恰好是它最大优势所在,因此近年来成为关节外科领域热点话题,备受关注。目的:文章将从机器人辅助全膝关节置换在关节外科领域的发展现状及其与传统全膝关节置换优劣势对比进行概述,此外,还将对机器人辅助全膝关节置换技术未来的发展进行展望。方法:应用计算机检索PubMed、中国知网、万方和维普数据库的相关文章,英文检索词:“robot OR robotic OR robotics OR robotically OR computer,total knee arthroplasty OR total knee replacement,TKA OR TKR”,中文检索词:“机器人辅助,计算机导航,全膝关节置换术”,最终纳入64篇文献进行综述分析。结果与结论:①用于辅助全膝关节置换的机器人系统根据其自由度分为主动式、半主动式和被动式。半主动式系统是目前使用最为广泛的机器人系统,该系统有效提高了全膝关节置换手术的精准性和个性化程度,但其高昂的使用成本与较长的学习曲线仍是在该领域内推广时需要权衡的主要因素。②机器人辅助全膝关节置换可实现膝关节局部三维空间的精准截骨、正确安置假体,已被广泛证明可以提供更好的假体植入精准度,减少影像学异常值,在术中可获得良好的软组织平衡,最终改善术后膝关节运动及功能状态。③但目前的机器人辅助系统依然存在客观的不足之处,包括不同机器人设备与术者之间的学习曲线问题、额外增加的安装和维护成本以及与机器人手术相关的潜在并发症,所以其能否让医疗系统及患者真正受益仍需要更长期的研究予以证明,机器人辅助系统也仍需进行更多实质性的改进。④机器人辅助全膝关节置换技术在临床上仍然处于初步研究阶段,并没有大范围地应用到临床,更加明确该技术的用法、完善该技术的临床操作规范和安全性成为了未来对该技术的研究侧重点。
