In the realm of quadruped robot locomotion,compliance control is imperative to handle impacts when negotiating unstructured terrains.At the same time,kinematic tracking accuracy should be guaranteed during locomotion....In the realm of quadruped robot locomotion,compliance control is imperative to handle impacts when negotiating unstructured terrains.At the same time,kinematic tracking accuracy should be guaranteed during locomotion.To meet both demands,ajoint space compliance controller is designed,so that compliance can be achieved in stance phase while position tracking performance can be guaranteed in swing phase.Unlike operational space compliance control,the joint space compliance control method is easy to implement and does not depend on robot dynamics.As for each joint actuator,high performance force control is of great importance for compliance design.Therefore,a nonlinear PI controller based on feedback linearization is proposed for the hydraulic actuator force control.Besides,an outer position loop（compliance loop）is closed for each joint.Experiments are carried out to verify the force controller and compliance of the hydraulic actuator.The robot leg compliance is assessed by a virtual prototyping simulation.展开更多
Assessing the radiographic features of knee osteoarthritis （OA）, especially joint space narrowing, is important for evaluating disease progression. The purpose of this study was to quantitatively analyze joint space...Assessing the radiographic features of knee osteoarthritis （OA）, especially joint space narrowing, is important for evaluating disease progression. The purpose of this study was to quantitatively analyze joint space narrowing by measuring 2 new variables： the average joint space width （aJSW） and the articulate angle （AA） on X-ray films, and to evaluate the relationship between the 2 variables, knee function and OA symptoms. Methods Using the web-based radiology viewer （Cedara I-ReachTM 4.1.1）, we measured the 2 variables in 50 knees of 41 patients with knee OA participating in the Shanghai OA Study. We also evaluated the Kellgren-Lawrence （K-L） grade, the Western Ontario and McMaster Universities OA Index （WOMAC）, and additional questionnaire in OA knees. The study was approved by the ethics committee of Shanghai Ninth People＇s Hospital （No. 2009-28）. Results The aJSW correlated with the K-L grade （r=-0.57, P 〈0.001）, kneeling （r=-0.29, P=0.04）, sitting cross-legged on the floor （r=-0.31, P=0.03）, WOMAC pain （r=-0.31, P=0.03）, WOMAC disability （r=-0.35, P=0.01）, pain while squatting （r=-0.37, P=0.01）, and defecating in a squatting position （r=-0.39, P= 0.01）. The AA correlated with defecating in a squatting position （r=0.29, P=0.05）, WOMAC disability （r=0.30, P=0.04） and K-L grade （r=0.44, P=0.003）. The K-L grade also correlated with pain while squatting （r=-0.40, P=0.005） and defecating in a squatting position （r=-0.34, P=0.02）, WOMAC pain （r=0.30, P=0.04）, and WOMAC disability （r=0.30, P=0.04）. Conclusions The aJSW closely correlated with knee OA symptoms and function scores, and was more sensitive to knee OA related disabilities than K-L grade and the AA. The aJSW could be used as a new variable for knee OA evaluation.展开更多
BACKGROUND The role of occlusal factors on the occurrence of temporomandibular joint disorders(TMDs)is still unclear and it is tricky for orthodontists to treat malocclusions in patients with TMDs.We report the case o...BACKGROUND The role of occlusal factors on the occurrence of temporomandibular joint disorders(TMDs)is still unclear and it is tricky for orthodontists to treat malocclusions in patients with TMDs.We report the case of the second orthodontic treatment of an adult female with Class II division 2 malocclusion associated with TMD.With the removal of anterior occlusal interference,TMD symptoms were alleviated and cone beam computed tomography(CBCT)images showed the bilateral condyles shifted forward.CASE SUMMARY This case report presented an orthodontic retreatment of an adult female with TMD and mandibular backward positioning based on CBCT examination and Joint Space Index(JSI)analysis.The left and right JSI values of-38.5 and-52.6 indicated that the position of bilateral condyles had posterior displacement.Ten years prior to this evaluation,she underwent orthodontic treatment resulting in the extraction of two upper premolars and one lower central incisor.The joint symptoms,including pain and sounds,were alleviated along with verified mandibular forward repositioning by extraction of another lower central incisor.CONCLUSION Mandibular backward positioning could be associated with TMD.JSI analysis based on CBCT is a convenient way to examine condylar positions quantitatively.展开更多
基金Supported by the National High Technology Research and Development Program of China(863 Program)(2011AA041002)
文摘In the realm of quadruped robot locomotion,compliance control is imperative to handle impacts when negotiating unstructured terrains.At the same time,kinematic tracking accuracy should be guaranteed during locomotion.To meet both demands,ajoint space compliance controller is designed,so that compliance can be achieved in stance phase while position tracking performance can be guaranteed in swing phase.Unlike operational space compliance control,the joint space compliance control method is easy to implement and does not depend on robot dynamics.As for each joint actuator,high performance force control is of great importance for compliance design.Therefore,a nonlinear PI controller based on feedback linearization is proposed for the hydraulic actuator force control.Besides,an outer position loop（compliance loop）is closed for each joint.Experiments are carried out to verify the force controller and compliance of the hydraulic actuator.The robot leg compliance is assessed by a virtual prototyping simulation.
文摘Assessing the radiographic features of knee osteoarthritis （OA）, especially joint space narrowing, is important for evaluating disease progression. The purpose of this study was to quantitatively analyze joint space narrowing by measuring 2 new variables： the average joint space width （aJSW） and the articulate angle （AA） on X-ray films, and to evaluate the relationship between the 2 variables, knee function and OA symptoms. Methods Using the web-based radiology viewer （Cedara I-ReachTM 4.1.1）, we measured the 2 variables in 50 knees of 41 patients with knee OA participating in the Shanghai OA Study. We also evaluated the Kellgren-Lawrence （K-L） grade, the Western Ontario and McMaster Universities OA Index （WOMAC）, and additional questionnaire in OA knees. The study was approved by the ethics committee of Shanghai Ninth People＇s Hospital （No. 2009-28）. Results The aJSW correlated with the K-L grade （r=-0.57, P 〈0.001）, kneeling （r=-0.29, P=0.04）, sitting cross-legged on the floor （r=-0.31, P=0.03）, WOMAC pain （r=-0.31, P=0.03）, WOMAC disability （r=-0.35, P=0.01）, pain while squatting （r=-0.37, P=0.01）, and defecating in a squatting position （r=-0.39, P= 0.01）. The AA correlated with defecating in a squatting position （r=0.29, P=0.05）, WOMAC disability （r=0.30, P=0.04） and K-L grade （r=0.44, P=0.003）. The K-L grade also correlated with pain while squatting （r=-0.40, P=0.005） and defecating in a squatting position （r=-0.34, P=0.02）, WOMAC pain （r=0.30, P=0.04）, and WOMAC disability （r=0.30, P=0.04）. Conclusions The aJSW closely correlated with knee OA symptoms and function scores, and was more sensitive to knee OA related disabilities than K-L grade and the AA. The aJSW could be used as a new variable for knee OA evaluation.
文摘BACKGROUND The role of occlusal factors on the occurrence of temporomandibular joint disorders(TMDs)is still unclear and it is tricky for orthodontists to treat malocclusions in patients with TMDs.We report the case of the second orthodontic treatment of an adult female with Class II division 2 malocclusion associated with TMD.With the removal of anterior occlusal interference,TMD symptoms were alleviated and cone beam computed tomography(CBCT)images showed the bilateral condyles shifted forward.CASE SUMMARY This case report presented an orthodontic retreatment of an adult female with TMD and mandibular backward positioning based on CBCT examination and Joint Space Index(JSI)analysis.The left and right JSI values of-38.5 and-52.6 indicated that the position of bilateral condyles had posterior displacement.Ten years prior to this evaluation,she underwent orthodontic treatment resulting in the extraction of two upper premolars and one lower central incisor.The joint symptoms,including pain and sounds,were alleviated along with verified mandibular forward repositioning by extraction of another lower central incisor.CONCLUSION Mandibular backward positioning could be associated with TMD.JSI analysis based on CBCT is a convenient way to examine condylar positions quantitatively.
