Aim Aiming at the position tracking control for valve controlled motor electrohydraulic proportional servo systems mainly driving the static load torque, the tracking performance was studied in the presence of the v...Aim Aiming at the position tracking control for valve controlled motor electrohydraulic proportional servo systems mainly driving the static load torque, the tracking performance was studied in the presence of the variable gain and deadzone. Methods On the basis of conventional composite control with the deadzone compensation method, a comprehensive control approach with the deadzone and self adjusting feedforward compensation was proposed. Results Experimental results showed that the good tracking performance was achieved for the sinusoidal and constant velocity position tracking under a wide variations of load torque. Conclusion The position tracking accuracy for valve controlled motor electrohydraulic proportional servo systems has been solved by using the comprehensive control approach with the deadzone and self adjusting feedforward compensation.展开更多
Aim In accordance with the positioning control for valve controlled motor electrohydraulic proportional servo systems driving the static load torque, the positioning performance was studied in the presence of the ti...Aim In accordance with the positioning control for valve controlled motor electrohydraulic proportional servo systems driving the static load torque, the positioning performance was studied in the presence of the time? varying deadzone and gain. Methods The large positioning errors caused by the time varying deadzone were significantly reduced by using the dynamic compensation method for the deadzone; and the large overshoot caused by the time varying gain were dramatically reduced by using the three section intelligent control schemes. Results Experimental results demonstrated that the positioning performance of rapid response, high accuracy and smaller or even no overshoot was achieved under a wide variations of load torque. Conclusion The good positioning performance for valve controlled motor servo systems has been achieved in the presence of the time varying deadzone and gain.展开更多
This paper presents an adaptive friction compensation method based on LuGre model for large diameter electric-hydraulic proportional valves in which the valve core contains friction.A mathematic model of the electric-...This paper presents an adaptive friction compensation method based on LuGre model for large diameter electric-hydraulic proportional valves in which the valve core contains friction.A mathematic model of the electric-hydraulic proportional valve is established,and the friction characteristics are described based on the LuGre model.The global asymptotic stability of the control system with the adaptive friction compensation controller is guaranteed over Lyapunov theorem.The adaptive compensation of the friction on LuGre friction model is verified by simulation and experiment.The steady-state error is about [-4.23 × 10^(-5)m,5.91 × 10^(-5)m]and[-2.5 × 10^(-4)m,2.6 ×10^(-4) m] on simulation and experiment,the position tracking accuracy is higher,and the lag time of the main valve through the dead zone is shorter.The result proves that the adaptive friction compensation method can effectively compensate for the negative effects of nonlinear friction.展开更多
In view of the uncertainty and complexity,the intelligent model of rehabilitation training program for stroke was proposed,combining with the case-based reasoning(CBR) and interval type-2 fuzzy reasoning(IT2FR).The mo...In view of the uncertainty and complexity,the intelligent model of rehabilitation training program for stroke was proposed,combining with the case-based reasoning(CBR) and interval type-2 fuzzy reasoning(IT2FR).The model consists of two parts:the setting model based on CBR and the feedback compensation model based on IT2FR.The former presets the value of rehabilitation training program,and the latter carries on the feedback compensation of the preset value.Experimental results show that the average percentage error of two rehabilitation training programs is 0.074%.The two programs are made by the intelligent model and rehabilitation physician.That is,the two different programs are nearly identical.It means that the intelligent model can make a rehabilitation training program effectively and improve the rehabilitation efficiency.展开更多
Power quality is a complex term that is defined by the legislation, but also as an obligation of the supplier and customer. The customer must return the negative effects of its consumers （taking reactive power, harmo...Power quality is a complex term that is defined by the legislation, but also as an obligation of the supplier and customer. The customer must return the negative effects of its consumers （taking reactive power, harmonic generation, phase unbalance） down to the prescribed limits. This primarily refers to the presence of non-linear consumers, leading to distortion of the basic parameters of voltage and current, in steady or transient conditions, and therefore the deformation of waveform. One way to reduce the negative feedback effects, especially with inductive loads, is the reactive energy compensation. The paper presents one of the solution for reactive power compensation, applied on the pumping station of public company ＂Waterworks and Sewerage---Bar＂, Bar.展开更多
There is a growing number of case reports of hepatoxicity from the widely marketed weight-loss supplement Hydroxycut, which contains the botanical ingredient Garcinia cambogia . These case reports may substantially un...There is a growing number of case reports of hepatoxicity from the widely marketed weight-loss supplement Hydroxycut, which contains the botanical ingredient Garcinia cambogia . These case reports may substantially undercount the true magnitude of harm. Based on the past experience with harmful dietary supplements, US regulators should assume the more precautionary approach favored by Canada and Europe. Lacking effective adverse event surveillance for supplements, or the requirements to prove safety prior to coming to the market, case reports such as those summarized here assume added importance.展开更多
Because it offers an effective means to alleviate current ecological problems and a way to coordinate sustainable economic and social development with protection of the environment,eco-compensation has become a subjec...Because it offers an effective means to alleviate current ecological problems and a way to coordinate sustainable economic and social development with protection of the environment,eco-compensation has become a subject of interest to scholars and governments all over the world.A great many studies have been carried out and eco-compensation schemes have been put into practice;there have been many fruitful results.Based on a review of related research and practices,this paper attempts first to discuss domestic and international eco-compensation research and practices in terms of the meaning of eco-compensation and its components（stakeholders,compensation criteria,compensation modes,compensation approaches,compensation funds,and compensation effects）.Next,taking into consideration the above discussion,the paper looks at the differences between Chinese and international eco-compensation measures.Finally,existing problems with eco-compensation research and practices in China are summarized and some suggestions are put forward.展开更多
This paper deals with the problem of accelerometer error estimation and compensation for a three-axis gyro-stabilized camera mount. In a dynamic environment, the aircraft motion acceleration affects the accelerome ：e...This paper deals with the problem of accelerometer error estimation and compensation for a three-axis gyro-stabilized camera mount. In a dynamic environment, the aircraft motion acceleration affects the accelerome ：er output and causes a degradation of attitude steady accuracy. In order to improve control accuracy, this paper proposes a proportional multiple-integral observer- based control strategy to estimate and compensate the accelerometer error. The basic idea of this paper is to approximate the error property by using a q-order polynomial function and extend the error and its derivatives as augmented states. Then a proportional multiple-integral observer is developed to estimate the error, with which the relationship between the error and the imbalance torque is formulated. The estimated value is compared to an angle threshold, the result of which is used to compen- sate the accelerometer output. Through static and vehicle-mounted experiments, it is demonstrated that compared with the tra- ditional method, the proposed method can improve the attitude steady accuracy effectively.展开更多
Introduction:Rectal prolapse is a condition that occurs infrequently in men and there is little literature guiding treatment in this population.The purpose of this study was to evaluate the surgical approach and outco...Introduction:Rectal prolapse is a condition that occurs infrequently in men and there is little literature guiding treatment in this population.The purpose of this study was to evaluate the surgical approach and outcomes of rectal-prolapse repair in men.Methods:A retrospective multicenter review was conducted of consecutive men who underwent rectal-prolapse repair between 2004 and 2014.Surgical approaches and outcomes,including erectile function and fecal continence,were evaluated.Results:During the study period,58 men underwent rectal-prolapse repair and the mean age of repair was 52.7624.1 years.The mean follow-up was 13.2 months(range,0.5–117 months).The majority of patients underwent endoscopic evaluation(78%),but few patients underwent anal manometry(16%),defecography(9%)or ultrasound(3%).Ten patients(17%)underwent biofeedback/pelvic-floor physical therapy prior to repair.Nineteen patients(33%)underwent a perineal approach(most were perineal proctosigmoidectomy).Thirty-nine patients(67%)underwent repair using an abdominal approach(all were suture rectopexy)and,of these,77%were completed using a minimally invasive technique.The overall complication rate was 26%including urinary retention(16%),which was more common in patients undergoing the perineal approach(32%vs.8%,P=0.028),urinary-tract infection(7%)and wound infection(3%).The overall recurrence rate was 9%,with no difference between abdominal and perineal approaches.Information on sexual function was missing in the majority of patients both before and after surgery(76%and 78%,respectively).Conclusion:Rectal-prolapse repair in men is safe and has a low recurrence rate;however,sexual function was poorly recorded across all institutions.Further studies are needed to evaluate to best approach to and functional outcomes of rectal-prolapse repair in men.展开更多
文摘Aim Aiming at the position tracking control for valve controlled motor electrohydraulic proportional servo systems mainly driving the static load torque, the tracking performance was studied in the presence of the variable gain and deadzone. Methods On the basis of conventional composite control with the deadzone compensation method, a comprehensive control approach with the deadzone and self adjusting feedforward compensation was proposed. Results Experimental results showed that the good tracking performance was achieved for the sinusoidal and constant velocity position tracking under a wide variations of load torque. Conclusion The position tracking accuracy for valve controlled motor electrohydraulic proportional servo systems has been solved by using the comprehensive control approach with the deadzone and self adjusting feedforward compensation.
文摘Aim In accordance with the positioning control for valve controlled motor electrohydraulic proportional servo systems driving the static load torque, the positioning performance was studied in the presence of the time? varying deadzone and gain. Methods The large positioning errors caused by the time varying deadzone were significantly reduced by using the dynamic compensation method for the deadzone; and the large overshoot caused by the time varying gain were dramatically reduced by using the three section intelligent control schemes. Results Experimental results demonstrated that the positioning performance of rapid response, high accuracy and smaller or even no overshoot was achieved under a wide variations of load torque. Conclusion The good positioning performance for valve controlled motor servo systems has been achieved in the presence of the time varying deadzone and gain.
基金Supported by the National Key Basic Research Program of China(No.2014CB046405)Key Projects in the National Science&Technology Pillar Program during the Twelfth Five-year Plan of China(No.2014BAF02B00,2011BAF09B04)
文摘This paper presents an adaptive friction compensation method based on LuGre model for large diameter electric-hydraulic proportional valves in which the valve core contains friction.A mathematic model of the electric-hydraulic proportional valve is established,and the friction characteristics are described based on the LuGre model.The global asymptotic stability of the control system with the adaptive friction compensation controller is guaranteed over Lyapunov theorem.The adaptive compensation of the friction on LuGre friction model is verified by simulation and experiment.The steady-state error is about [-4.23 × 10^(-5)m,5.91 × 10^(-5)m]and[-2.5 × 10^(-4)m,2.6 ×10^(-4) m] on simulation and experiment,the position tracking accuracy is higher,and the lag time of the main valve through the dead zone is shorter.The result proves that the adaptive friction compensation method can effectively compensate for the negative effects of nonlinear friction.
基金Project(2010020176-301)supported by Liaoning Science and Technology Program,ChinaProject(F10-2D5-1-57)supported by Shenyang Municipal Fund,China
文摘In view of the uncertainty and complexity,the intelligent model of rehabilitation training program for stroke was proposed,combining with the case-based reasoning(CBR) and interval type-2 fuzzy reasoning(IT2FR).The model consists of two parts:the setting model based on CBR and the feedback compensation model based on IT2FR.The former presets the value of rehabilitation training program,and the latter carries on the feedback compensation of the preset value.Experimental results show that the average percentage error of two rehabilitation training programs is 0.074%.The two programs are made by the intelligent model and rehabilitation physician.That is,the two different programs are nearly identical.It means that the intelligent model can make a rehabilitation training program effectively and improve the rehabilitation efficiency.
文摘Power quality is a complex term that is defined by the legislation, but also as an obligation of the supplier and customer. The customer must return the negative effects of its consumers （taking reactive power, harmonic generation, phase unbalance） down to the prescribed limits. This primarily refers to the presence of non-linear consumers, leading to distortion of the basic parameters of voltage and current, in steady or transient conditions, and therefore the deformation of waveform. One way to reduce the negative feedback effects, especially with inductive loads, is the reactive energy compensation. The paper presents one of the solution for reactive power compensation, applied on the pumping station of public company ＂Waterworks and Sewerage---Bar＂, Bar.
文摘There is a growing number of case reports of hepatoxicity from the widely marketed weight-loss supplement Hydroxycut, which contains the botanical ingredient Garcinia cambogia . These case reports may substantially undercount the true magnitude of harm. Based on the past experience with harmful dietary supplements, US regulators should assume the more precautionary approach favored by Canada and Europe. Lacking effective adverse event surveillance for supplements, or the requirements to prove safety prior to coming to the market, case reports such as those summarized here assume added importance.
基金National Key R&D Plan(2016YFC0503405)National Natural Science Foundation of China(51379084)
文摘Because it offers an effective means to alleviate current ecological problems and a way to coordinate sustainable economic and social development with protection of the environment,eco-compensation has become a subject of interest to scholars and governments all over the world.A great many studies have been carried out and eco-compensation schemes have been put into practice;there have been many fruitful results.Based on a review of related research and practices,this paper attempts first to discuss domestic and international eco-compensation research and practices in terms of the meaning of eco-compensation and its components（stakeholders,compensation criteria,compensation modes,compensation approaches,compensation funds,and compensation effects）.Next,taking into consideration the above discussion,the paper looks at the differences between Chinese and international eco-compensation measures.Finally,existing problems with eco-compensation research and practices in China are summarized and some suggestions are put forward.
基金supported by the National Natural Science Foundation of China(Grant Nos.61174121,61333005 and 61121003)the Ph.D Programs Foundations of the Ministry of Education China
文摘This paper deals with the problem of accelerometer error estimation and compensation for a three-axis gyro-stabilized camera mount. In a dynamic environment, the aircraft motion acceleration affects the accelerome ：er output and causes a degradation of attitude steady accuracy. In order to improve control accuracy, this paper proposes a proportional multiple-integral observer- based control strategy to estimate and compensate the accelerometer error. The basic idea of this paper is to approximate the error property by using a q-order polynomial function and extend the error and its derivatives as augmented states. Then a proportional multiple-integral observer is developed to estimate the error, with which the relationship between the error and the imbalance torque is formulated. The estimated value is compared to an angle threshold, the result of which is used to compen- sate the accelerometer output. Through static and vehicle-mounted experiments, it is demonstrated that compared with the tra- ditional method, the proposed method can improve the attitude steady accuracy effectively.
文摘Introduction:Rectal prolapse is a condition that occurs infrequently in men and there is little literature guiding treatment in this population.The purpose of this study was to evaluate the surgical approach and outcomes of rectal-prolapse repair in men.Methods:A retrospective multicenter review was conducted of consecutive men who underwent rectal-prolapse repair between 2004 and 2014.Surgical approaches and outcomes,including erectile function and fecal continence,were evaluated.Results:During the study period,58 men underwent rectal-prolapse repair and the mean age of repair was 52.7624.1 years.The mean follow-up was 13.2 months(range,0.5–117 months).The majority of patients underwent endoscopic evaluation(78%),but few patients underwent anal manometry(16%),defecography(9%)or ultrasound(3%).Ten patients(17%)underwent biofeedback/pelvic-floor physical therapy prior to repair.Nineteen patients(33%)underwent a perineal approach(most were perineal proctosigmoidectomy).Thirty-nine patients(67%)underwent repair using an abdominal approach(all were suture rectopexy)and,of these,77%were completed using a minimally invasive technique.The overall complication rate was 26%including urinary retention(16%),which was more common in patients undergoing the perineal approach(32%vs.8%,P=0.028),urinary-tract infection(7%)and wound infection(3%).The overall recurrence rate was 9%,with no difference between abdominal and perineal approaches.Information on sexual function was missing in the majority of patients both before and after surgery(76%and 78%,respectively).Conclusion:Rectal-prolapse repair in men is safe and has a low recurrence rate;however,sexual function was poorly recorded across all institutions.Further studies are needed to evaluate to best approach to and functional outcomes of rectal-prolapse repair in men.
