This paper presents the design,and validation of a new adaptive control system based on quasi-time delay estimation(Q-TDE)augmented with new integral second-order terminal sliding mode control(ISOTSMC)for a manipulato...This paper presents the design,and validation of a new adaptive control system based on quasi-time delay estimation(Q-TDE)augmented with new integral second-order terminal sliding mode control(ISOTSMC)for a manipulator robot with unknown dynamicuncertainty and disturbances.Contrary to the conventional[TDE,the proposed Q-TDE becomes sufficient to invoke a fixed artficial time delay and utilize the past data only of the control input to approximate the unknown system's dynamic uncertainties.The incorporating of new adaptive reachinglaw with ISOTSMCaugmented with Q-TDE policy ensures the continuous performance tracking of the robot manipulator's trajectories using output feedback.This combination may achieve high performance with a significant chattering reducing procedure.By utilizing the Lyapunov function theory,it can be demonstrated that the robot system is stable and all signals in closed-loop are converging in finite time.Consequently,Simulation and comparative studies with two degrees of freedom robot manipulator were carried out to validate the effectiveness of the designed control scheme.展开更多
Spine biomechanical testing methods in the past few decades have not evolved beyond employing either cadaveric studies or finite element modeling techniques.However,both these approaches may have inherent cost and tim...Spine biomechanical testing methods in the past few decades have not evolved beyond employing either cadaveric studies or finite element modeling techniques.However,both these approaches may have inherent cost and time limitations.Cadaveric studies are the present gold standard for spinal implant design and regulatory approval,but they introduce significant variability in measurements across patients,often requiring large sample sizes.Finite element modeling demands considerable expertise and can be computationally expensive when complex geometry and material nonlinearity are introduced.Validated analogue spine models could complement these traditional methods as a low-cost and high-fidelity alternative.A fully 3D printable L-S1 analogue spine model with ligaments is developed and validated in this research.Rotational stiffness of the model under pure bending loading in flexion-extension,Lateral Bending(LB)and Axial Rotation(AR)is evaluated and compared against historical ex vivo and in silico models.Additionally,the effect of interspinous,intertransverse ligaments and the Thoracolumbar Fascia(TLF)on spinal stiffness is evaluated by systematic construction of the model.In flexion,model Range of Motion(ROM)was 12.92±0.11°(ex vivo:16.58°,in silico:12.96°)at 7.5Nm.In LB,average ROM was 13.67±0.12°at 7.5 Nm(ex vivo:15.21±1.89°,in silico:15.49±0.23°).Similarly,in AR,average ROM was 17.69±2.12°at 7.5Nm(ex vivo:14.12±0.31°,in silico:15.91±0.28°).The addition of interspinous and intertransverse ligaments increased both flexion and LB stiffnesses by approximately 5%.Addition of TLF showed increase in flexion and AR stiffnesses by 29%and 24%,respectively.This novel model can reproduce physiological ROMs with high repeatability and could be a useful open-source tool in spine biomechanics.展开更多
Abnormal subchondral bone remodeling leading to sclerosis is a main feature of osteoarthritis(OA), and osteomodulin(OMD), a proteoglycan involved in extracellular matrix mineralization, is associated with the scleroti...Abnormal subchondral bone remodeling leading to sclerosis is a main feature of osteoarthritis(OA), and osteomodulin(OMD), a proteoglycan involved in extracellular matrix mineralization, is associated with the sclerotic phenotype. However, the functions of OMD remain poorly understood, specifically in vivo. We used Omd knockout and overexpressing male mice and mutant zebrafish to study its roles in bone and cartilage metabolism and in the development of OA. The expression of Omd is deeply correlated with bone and cartilage microarchitectures affecting the bone volume and the onset of subchondral bone sclerosis and spontaneous cartilage lesions. Mechanistically, OMD binds to RANKL and inhibits osteoclastogenesis, thus controlling the balance of bone remodeling. In conclusion, OMD is a key factor in subchondral bone sclerosis associated with OA. It participates in bone and cartilage homeostasis by acting on the regulation of osteoclastogenesis. Targeting OMD may be a promising new and personalized approach for OA.展开更多
1.Introduction Calcium phosphate ceramics,such as hydroxyapatite or tricalciumphosphate as well as bioglass,are successfully used as coatings to improve the fixation of dental implants or load-bearing implants in the ...1.Introduction Calcium phosphate ceramics,such as hydroxyapatite or tricalciumphosphate as well as bioglass,are successfully used as coatings to improve the fixation of dental implants or load-bearing implants in the human bone[1].The demand for surgical procedures such as hip and knee arthroplasties,primary as well as revision procedures,is projected to increase for the foreseeable future[2].The possibility of an infection is amajor risk for all implants[3].The treatment of these periprosthetic joint infections is difficult and often requires the replacement of the implant[4],which is a significant burden for the patient and comes at an increased economic cost[5].展开更多
文摘This paper presents the design,and validation of a new adaptive control system based on quasi-time delay estimation(Q-TDE)augmented with new integral second-order terminal sliding mode control(ISOTSMC)for a manipulator robot with unknown dynamicuncertainty and disturbances.Contrary to the conventional[TDE,the proposed Q-TDE becomes sufficient to invoke a fixed artficial time delay and utilize the past data only of the control input to approximate the unknown system's dynamic uncertainties.The incorporating of new adaptive reachinglaw with ISOTSMCaugmented with Q-TDE policy ensures the continuous performance tracking of the robot manipulator's trajectories using output feedback.This combination may achieve high performance with a significant chattering reducing procedure.By utilizing the Lyapunov function theory,it can be demonstrated that the robot system is stable and all signals in closed-loop are converging in finite time.Consequently,Simulation and comparative studies with two degrees of freedom robot manipulator were carried out to validate the effectiveness of the designed control scheme.
基金the Natural Science and Engineering Research Council of Canada(NSERC,grant no.NSERC 250992 and 245375)Fonds de recherche du Québec(FRQNT,grant no.315108 and 332139)。
文摘Spine biomechanical testing methods in the past few decades have not evolved beyond employing either cadaveric studies or finite element modeling techniques.However,both these approaches may have inherent cost and time limitations.Cadaveric studies are the present gold standard for spinal implant design and regulatory approval,but they introduce significant variability in measurements across patients,often requiring large sample sizes.Finite element modeling demands considerable expertise and can be computationally expensive when complex geometry and material nonlinearity are introduced.Validated analogue spine models could complement these traditional methods as a low-cost and high-fidelity alternative.A fully 3D printable L-S1 analogue spine model with ligaments is developed and validated in this research.Rotational stiffness of the model under pure bending loading in flexion-extension,Lateral Bending(LB)and Axial Rotation(AR)is evaluated and compared against historical ex vivo and in silico models.Additionally,the effect of interspinous,intertransverse ligaments and the Thoracolumbar Fascia(TLF)on spinal stiffness is evaluated by systematic construction of the model.In flexion,model Range of Motion(ROM)was 12.92±0.11°(ex vivo:16.58°,in silico:12.96°)at 7.5Nm.In LB,average ROM was 13.67±0.12°at 7.5 Nm(ex vivo:15.21±1.89°,in silico:15.49±0.23°).Similarly,in AR,average ROM was 17.69±2.12°at 7.5Nm(ex vivo:14.12±0.31°,in silico:15.91±0.28°).The addition of interspinous and intertransverse ligaments increased both flexion and LB stiffnesses by approximately 5%.Addition of TLF showed increase in flexion and AR stiffnesses by 29%and 24%,respectively.This novel model can reproduce physiological ROMs with high repeatability and could be a useful open-source tool in spine biomechanics.
基金funded by the F.R.S.-FNRS for the “EOS: The Excellence of Science-Join-t-against-Osteoarthritis”, grant number 30480119by a research grant from the Osteoarthritis Foundation and by the University of Liege (Fonds Léon Fredericq and Fonds Speciaux à la Recherche)funded by Versus Arthritis senior fellowship 21937。
文摘Abnormal subchondral bone remodeling leading to sclerosis is a main feature of osteoarthritis(OA), and osteomodulin(OMD), a proteoglycan involved in extracellular matrix mineralization, is associated with the sclerotic phenotype. However, the functions of OMD remain poorly understood, specifically in vivo. We used Omd knockout and overexpressing male mice and mutant zebrafish to study its roles in bone and cartilage metabolism and in the development of OA. The expression of Omd is deeply correlated with bone and cartilage microarchitectures affecting the bone volume and the onset of subchondral bone sclerosis and spontaneous cartilage lesions. Mechanistically, OMD binds to RANKL and inhibits osteoclastogenesis, thus controlling the balance of bone remodeling. In conclusion, OMD is a key factor in subchondral bone sclerosis associated with OA. It participates in bone and cartilage homeostasis by acting on the regulation of osteoclastogenesis. Targeting OMD may be a promising new and personalized approach for OA.
基金The authors would like to thank the Deutsche Forschungsgemeinschaft DFG for the funding of this work under grant GA 589/11-1 and BE 1964/8-1.
文摘1.Introduction Calcium phosphate ceramics,such as hydroxyapatite or tricalciumphosphate as well as bioglass,are successfully used as coatings to improve the fixation of dental implants or load-bearing implants in the human bone[1].The demand for surgical procedures such as hip and knee arthroplasties,primary as well as revision procedures,is projected to increase for the foreseeable future[2].The possibility of an infection is amajor risk for all implants[3].The treatment of these periprosthetic joint infections is difficult and often requires the replacement of the implant[4],which is a significant burden for the patient and comes at an increased economic cost[5].
