BACKGROUND Two-stage revision is the most common treatment for chronic periprosthetic joint infection of the hip,involving a resection arthroplasty with or without placement of an antibiotic-loaded spacer,followed by ...BACKGROUND Two-stage revision is the most common treatment for chronic periprosthetic joint infection of the hip,involving a resection arthroplasty with or without placement of an antibiotic-loaded spacer,followed by antibiotic therapy before reimplantation.AIM To compare the outcomes and complications of two consecutive treatment protocols for two-stage revision arthroplasty of the infected hip:One using Girdlestone with an antibiotic holiday,the other using custom-made articulating spacers(CUMARS)without an antibiotic holiday.METHODS In this retrospective study,two consecutive cohorts were compared.Group A(2017-2020)underwent two-stage revision with a Girdlestone and an antibiotic holiday before reimplantation,while Group B(2020-2023)received CUMARS whenever possible,and no antibiotic holiday,or a Girdlestone if indicated.The primary outcome was successful infection eradication after one year.Secondary outcomes included surgical duration,length of hospital stay,weight-bearing allowance,discharge destination,and complications.RESULTS A total of 98 patients were included:39 patients in Group A and 59 patients in Group B.Successful infection eradication after one year was achieved in 69%of Group A and 83%of Group B(P=0.164).Patients in Group B were more frequently allowed to bear weight(64%vs 18%,P<0.001),had a shorter in-hospital stay(9 vs 16 days,P<0.001),and were more often discharged home after the first surgery(48%vs 24%,P=0.048).No significant differences were found in(mechanical)complications.CONCLUSION A protocol including CUMARS is a safe and effective treatment,offering faster recovery,shorter length of hospital stay,and enabling more patients to return home during the interval.This reduces strain on patients and the healthcare system,potentially saving costs,without compromising infection control or increasing(mechanical)complications.展开更多
Virtual prototype of pipe wagon articulating (PWA) system has been developed and simulated based on the kinematics and dynamics of machinery and Automatic Dynamic Analysis of Mechanical Systems (ADAMS) software. It ha...Virtual prototype of pipe wagon articulating (PWA) system has been developed and simulated based on the kinematics and dynamics of machinery and Automatic Dynamic Analysis of Mechanical Systems (ADAMS) software. It has been integrated with real-time three dimensional (3-D) system simulations for detailed and responsive interaction with dynamic virtual environments. By using this virtual model, the conceptual design examination and performance analysis of the PWA system have been realized dynamically in virtual laboratory. System dynamic force, displacement and tension of pipe have been measured through verifying this 3- D virtual prototype. By comparing the static tension and dynamic tension of pipe, the difference between the two kind tensions has been found. The simulated dynamic tension is much greater than the static tension obtained from the static theory. The results attained in this work suggest that the conceptual designed PWA system can meet the requirements of the operation.展开更多
BACKGROUND Two-stage revision arthroplasty with an antibiotic-loaded spacer is the treatment of choice in chronically infected total hip arthroplasties.Interval spacers can be functional articulating or prefabricated....BACKGROUND Two-stage revision arthroplasty with an antibiotic-loaded spacer is the treatment of choice in chronically infected total hip arthroplasties.Interval spacers can be functional articulating or prefabricated.Functional results of these spacers have scarcely been reported.AIM To compare retrospectively the patient reported outcome and infection eradication rate after two-stage revision arthroplasty of the hip with the use of a functional articulating or prefabricated spacer.METHODS All patients with two-stage revision of a hip prosthesis at our hospital between 2003 and 2016 were included in this retrospective cohort study.Patients were divided into two groups;patients treated with a functional articulating spacer or with a prefabricated spacer.Patients completed the Hip Osteoarthritis Outcome Score and the EQ-5D-3L(EQ-5D)and the EQ-5D quality of life thermometer(EQVAS)scores.Primary outcomes were patient reported outcome and infection eradication after two-stage revision.The results of both groups were compared to the patient acceptable symptom state for primary arthroplasty of the hip.Secondary outcomes were complications during spacer treatment and at final follow-up.Descriptive statistics,mean and range are used to represent the demographics of the patients.For numerical variables,students’t-tests were used to assess the level of significance for differences between the groups,with 95%confidence intervals;for binary outcome,we used Fisher’s exact test.RESULTS We consecutively treated 55 patients with a prefabricated spacer and 15 patients with a functional articulating spacer of the hip.The infection eradication rates for functional articulating and prefabricated spacers were 93%and 78%,respectively(P>0.05).With respect to the functional outcome,the Hip Osteoarthritis Outcome Score(HOOS)and its subscores(all P<0.01),the EQ-5D(P<0.01)and the EQVAS scores(P<0.05)were all significantly better for patients successfully treated with a functional articulating spacer.More patients in the functional articulating spacer group reached the patient acceptable symptom state for the HOOS pain,HOOS quality of life and EQ-VAS.The number of patients with a spacer dislocation was not significantly different for the functional articulating or prefabricated spacer group(P>0.05).However,the number of dislocations per patient experiencing a dislocation was significantly higher for patients with a prefabricated spacer(P<0.01).CONCLUSION Functional articulating spacers lead to improved patient reported functional outcome and less perioperative complications after two-stage revision arthroplasty of an infected total hip prosthesis,while maintaining a similar infection eradication rate compared to prefabricated spacers.展开更多
This paper reports a case of cerebral stem infarction with quadriplegia and complete dependence on daily life.The course of the disease lasted more than 7 months.Frenchay's improved articulation Disorder Assessmen...This paper reports a case of cerebral stem infarction with quadriplegia and complete dependence on daily life.The course of the disease lasted more than 7 months.Frenchay's improved articulation Disorder Assessment Form has been assessed as severe articulation disorder.The patient has significantly improved his speech function and quality of life after systematic head control training,respiratory function training,articulation motor training,and articulation training.In the course of treatment,emphasis was placed on head postural control training and respiratory function training,and emphasis was placed on the strength and coordination training of articulatory organs,and the results were remarkable.After the patient was discharged from the hospital,the follow-up of basic daily life communication was not limited.展开更多
Safety berms(also called safety bunds or windrows),widely employed in surface mining and quarry operations,are typically designed based on rules of thumb.Despite having been used by the industry for more than half a c...Safety berms(also called safety bunds or windrows),widely employed in surface mining and quarry operations,are typically designed based on rules of thumb.Despite having been used by the industry for more than half a century and accidents happening regularly,their behaviour is still poorly understood.This paper challenges existing practices through a comprehensive investigation combining full-scale experiments and advanced numerical modelling.Focusing on a Volvo A45G articulated dump truck(ADT)and a CAT 773B rigid dump truck(RDT),collision scenarios under various approach conditions and different safety berm geometries and materials are rigorously examined.The calibrated numerical model is used to assess the energy absorption capacity of safety berms with different geometry and to predict a critical velocity for a specific scenario.Back analysis of an actual fatal accident indicated that an ADT adhering to the speed limit could not be stopped by the safety berm designed under current guidelines.The study highlights the importance of considering the entire geometry and the mass and volume of the material used to build the safety berm alongside the speed and approach conditions of the machinery.The findings of the study enable operators to set speed limits based on specific berm geometries or adapt safety berm designs to match speed constraints for specific machinery.This will reduce the risk of fatal accidents and improve haul road safety.展开更多
Objective To observe the effect of acupuncture combined with speech therapy on dysarthria after stroke or cerebral trauma. Methods Sixty-one cases of dysarthria were randomly divided into two groups. The observation g...Objective To observe the effect of acupuncture combined with speech therapy on dysarthria after stroke or cerebral trauma. Methods Sixty-one cases of dysarthria were randomly divided into two groups. The observation group （30 cases） was treated with speech therapy and acupuncture at major acupoints Lianquan （廉泉 CV 23）, Jinjin （金津 EX-HN 12）, Yuye （玉夜 EX-HN 13）, Fengchi（风池 GB 20）, Yifeng （翳风 TE 17） and Wangu（完骨 GB 12）, and the control group （31 cases） was treated with speech therapy only. The changes of speech and acoustical indices were evaluated after 9 weeks treatment. Results The word articulation and the correct rate of writings in the two groups were significantly increased after treatment （both P〈0.01）. The total effective rate of 96.7%（29/30） in the observation group was superior to that of 67.7%（21/31） in the control group （P〈0.01）. The maximum phonation time （MPT） tested by a phonolaryngeal aeromechanical analyzer was significantly prolonged in both the observation group （12 cases） and the control group （11 cases） （both P〈0.01）, the improvement in the observation group being more obvious （P〈0.01）. Conclusion Acupuncture combined with speech therapy can improve the speech and acoustic level in the patient of dysarthria.展开更多
Superplasticity of AZ 31 magnesium matrix composites reinforced with 10 vol% SiC（2 μm） particulate i s investigated at temperature range from 365℃ to 565℃ and strain rate from 2.0 8×10<sup>-3</sup&g...Superplasticity of AZ 31 magnesium matrix composites reinforced with 10 vol% SiC（2 μm） particulate i s investigated at temperature range from 365℃ to 565℃ and strain rate from 2.0 8×10<sup>-3</sup> to 5.21×10<sup>-1</sup> s<sup>-1</sup>. The maximum total elongation of 228 % is obtained at a strain rate of 2.08×10<sup>-1</sup> s<sup>-1</sup>. The strain rate se nsitivity exponent （m） higher than 0.3, is observed when the strain rate is high er than 10<sup>-1</sup> s<sup>-1</sup> at 525℃. Increasing the test temperature to 540℃, the maximum total elongation exceeding 195% is achieved at a higher strain rate of 5.21×10<sup>-1</sup> s<sup>-1</sup> than that at 525℃. SiC in AZ31/SiCp composite ca n fine the matrix grain size. Filament is observed on the fracture surface of th e specimens showing superplasticity.展开更多
目前Microsoft Power Point(PPT)在多媒体课件制作软件中占据了主导地位,但PPT课件用在基于网络化、数字化的教学中有着先天性不足。文章从多媒体元素、PPT兼容、平台(Flash vs Html 5)、技术的可用性和技术的教学性五个方面对基于PPT...目前Microsoft Power Point(PPT)在多媒体课件制作软件中占据了主导地位,但PPT课件用在基于网络化、数字化的教学中有着先天性不足。文章从多媒体元素、PPT兼容、平台(Flash vs Html 5)、技术的可用性和技术的教学性五个方面对基于PPT扩展应用的三款主流快速课件制作工具(Articulate Studio 13、i Spring Presenter 7、Adobe Presenter 9)进行了横向对比,分析了其制作网络化多媒体课件的优势,总结了快速课件制作的发展趋势,以期为创建适用于网络化、数字化教学需求的多媒体课件提供借鉴。展开更多
A principal component analysis-cerebellar model articulation controller （PCA-CMAC） model is proposed for machine performance degradation assessment.PCA is used to feature selection,which eliminates the redundant inf...A principal component analysis-cerebellar model articulation controller （PCA-CMAC） model is proposed for machine performance degradation assessment.PCA is used to feature selection,which eliminates the redundant information among the features from the sensor signals and reduces the dimension of the input to CMAC.CMAC is used to assess degradation states quantitatively based on its local generalization ability.The implementation of the model is presented and the model is applied in a drilling machine to assess the states of the cutting tool. The results show that the model can assess the wear states quantitatively based on the normal state of the cutting tool.The influence of the quantization parameter g and the generalization parameter r in the CMAC model on the assessment results is analyzed.If g is larger,the generalization ability is better,but the difference of degradation states is not obvious.If r is smaller,the different states are distinct,but memory requirements for storing the weights are larger.The principle for selecting two parameters is that the memory storing the weights should be small while the degradation states should be easily distinguished.展开更多
The accuracy of an articulated torque analysis influences the comprehensive performances of heavy-duty multi-legged robots. Currently, the extremal estimation method and some complex methods are employed to calculate ...The accuracy of an articulated torque analysis influences the comprehensive performances of heavy-duty multi-legged robots. Currently, the extremal estimation method and some complex methods are employed to calculate the articulated torques, which results in a large safety margin or a large number of calculations. To quickly obtain accurate articulated torques, an analysis method for the articulated torque is presented for an electrically driven heavy-duty six-legged robot. First, the rearmost leg that experiences the maximum normal contact force is confirmed when the robot transits a slope. Based on the ant-type and crab-type tripod gaits, the formulas of classical mechanics and MATLAB software are employed to theoretically analyze the relevant static torques of the joints. With the changes in the joint angles for the abductor joint, hip joint, and knee joint, variable tendency charts and extreme curves are obtained for the static articulated torques. Meanwhile, the maximum static articulated torques and the corresponding poses of the robot are also obtained. According to the poses of the robot under the maximum static articulated torques, ADAMS software is used to carry out a static simulation analysis. Based on the relevant simulation curves of the articulated torques, the maximum static articulated torques are acquired. A comparative analysis of the maximum static articulated torques shows that the theoretical calculation values are higher than the static simulation values, and the maximum error value is approximately 10%. The proposed method lays a foundation for quickly determining accurate articulated torques to develop heavy-duty six-legged robots.展开更多
This paper designs a novel controller to improve the path-tracking performance of articulated dump truck(ADT). By combining linear quadratic regulator(LQR) with genetic algorithm(GA), the designed controller is used t...This paper designs a novel controller to improve the path-tracking performance of articulated dump truck(ADT). By combining linear quadratic regulator(LQR) with genetic algorithm(GA), the designed controller is used to control linear and angular velocities on the midpoint of the front frame. The novel controller based on the error dynamics model is eventually realized to track the path high-precisely with constant speed. The results of simulation and experiment show that the LQR-GA controller has a better tracking performance than the existing methods under a low speed of 3 m/s. In this paper, kinematics model and simulation control models based on co-simulation of ADAMS and Matlab/Simulink are established to verify the proposed strategy. In addition, a real vehicle experiment is designed to further more correctness of the conclusion. With the proposed controller and considering the steering model in the simulation, the control performance is improved and matches the actual situation better. The research results contribute to the development of automation of ADT.展开更多
文摘BACKGROUND Two-stage revision is the most common treatment for chronic periprosthetic joint infection of the hip,involving a resection arthroplasty with or without placement of an antibiotic-loaded spacer,followed by antibiotic therapy before reimplantation.AIM To compare the outcomes and complications of two consecutive treatment protocols for two-stage revision arthroplasty of the infected hip:One using Girdlestone with an antibiotic holiday,the other using custom-made articulating spacers(CUMARS)without an antibiotic holiday.METHODS In this retrospective study,two consecutive cohorts were compared.Group A(2017-2020)underwent two-stage revision with a Girdlestone and an antibiotic holiday before reimplantation,while Group B(2020-2023)received CUMARS whenever possible,and no antibiotic holiday,or a Girdlestone if indicated.The primary outcome was successful infection eradication after one year.Secondary outcomes included surgical duration,length of hospital stay,weight-bearing allowance,discharge destination,and complications.RESULTS A total of 98 patients were included:39 patients in Group A and 59 patients in Group B.Successful infection eradication after one year was achieved in 69%of Group A and 83%of Group B(P=0.164).Patients in Group B were more frequently allowed to bear weight(64%vs 18%,P<0.001),had a shorter in-hospital stay(9 vs 16 days,P<0.001),and were more often discharged home after the first surgery(48%vs 24%,P=0.048).No significant differences were found in(mechanical)complications.CONCLUSION A protocol including CUMARS is a safe and effective treatment,offering faster recovery,shorter length of hospital stay,and enabling more patients to return home during the interval.This reduces strain on patients and the healthcare system,potentially saving costs,without compromising infection control or increasing(mechanical)complications.
文摘Virtual prototype of pipe wagon articulating (PWA) system has been developed and simulated based on the kinematics and dynamics of machinery and Automatic Dynamic Analysis of Mechanical Systems (ADAMS) software. It has been integrated with real-time three dimensional (3-D) system simulations for detailed and responsive interaction with dynamic virtual environments. By using this virtual model, the conceptual design examination and performance analysis of the PWA system have been realized dynamically in virtual laboratory. System dynamic force, displacement and tension of pipe have been measured through verifying this 3- D virtual prototype. By comparing the static tension and dynamic tension of pipe, the difference between the two kind tensions has been found. The simulated dynamic tension is much greater than the static tension obtained from the static theory. The results attained in this work suggest that the conceptual designed PWA system can meet the requirements of the operation.
文摘BACKGROUND Two-stage revision arthroplasty with an antibiotic-loaded spacer is the treatment of choice in chronically infected total hip arthroplasties.Interval spacers can be functional articulating or prefabricated.Functional results of these spacers have scarcely been reported.AIM To compare retrospectively the patient reported outcome and infection eradication rate after two-stage revision arthroplasty of the hip with the use of a functional articulating or prefabricated spacer.METHODS All patients with two-stage revision of a hip prosthesis at our hospital between 2003 and 2016 were included in this retrospective cohort study.Patients were divided into two groups;patients treated with a functional articulating spacer or with a prefabricated spacer.Patients completed the Hip Osteoarthritis Outcome Score and the EQ-5D-3L(EQ-5D)and the EQ-5D quality of life thermometer(EQVAS)scores.Primary outcomes were patient reported outcome and infection eradication after two-stage revision.The results of both groups were compared to the patient acceptable symptom state for primary arthroplasty of the hip.Secondary outcomes were complications during spacer treatment and at final follow-up.Descriptive statistics,mean and range are used to represent the demographics of the patients.For numerical variables,students’t-tests were used to assess the level of significance for differences between the groups,with 95%confidence intervals;for binary outcome,we used Fisher’s exact test.RESULTS We consecutively treated 55 patients with a prefabricated spacer and 15 patients with a functional articulating spacer of the hip.The infection eradication rates for functional articulating and prefabricated spacers were 93%and 78%,respectively(P>0.05).With respect to the functional outcome,the Hip Osteoarthritis Outcome Score(HOOS)and its subscores(all P<0.01),the EQ-5D(P<0.01)and the EQVAS scores(P<0.05)were all significantly better for patients successfully treated with a functional articulating spacer.More patients in the functional articulating spacer group reached the patient acceptable symptom state for the HOOS pain,HOOS quality of life and EQ-VAS.The number of patients with a spacer dislocation was not significantly different for the functional articulating or prefabricated spacer group(P>0.05).However,the number of dislocations per patient experiencing a dislocation was significantly higher for patients with a prefabricated spacer(P<0.01).CONCLUSION Functional articulating spacers lead to improved patient reported functional outcome and less perioperative complications after two-stage revision arthroplasty of an infected total hip prosthesis,while maintaining a similar infection eradication rate compared to prefabricated spacers.
基金Teaching and Research Project of Anhui Urban Management Vocational College(Project No.:2024kfkc001)。
文摘This paper reports a case of cerebral stem infarction with quadriplegia and complete dependence on daily life.The course of the disease lasted more than 7 months.Frenchay's improved articulation Disorder Assessment Form has been assessed as severe articulation disorder.The patient has significantly improved his speech function and quality of life after systematic head control training,respiratory function training,articulation motor training,and articulation training.In the course of treatment,emphasis was placed on head postural control training and respiratory function training,and emphasis was placed on the strength and coordination training of articulatory organs,and the results were remarkable.After the patient was discharged from the hospital,the follow-up of basic daily life communication was not limited.
基金initiated and financially supported by Stevenson Aggregates and Fulton Hogan.
文摘Safety berms(also called safety bunds or windrows),widely employed in surface mining and quarry operations,are typically designed based on rules of thumb.Despite having been used by the industry for more than half a century and accidents happening regularly,their behaviour is still poorly understood.This paper challenges existing practices through a comprehensive investigation combining full-scale experiments and advanced numerical modelling.Focusing on a Volvo A45G articulated dump truck(ADT)and a CAT 773B rigid dump truck(RDT),collision scenarios under various approach conditions and different safety berm geometries and materials are rigorously examined.The calibrated numerical model is used to assess the energy absorption capacity of safety berms with different geometry and to predict a critical velocity for a specific scenario.Back analysis of an actual fatal accident indicated that an ADT adhering to the speed limit could not be stopped by the safety berm designed under current guidelines.The study highlights the importance of considering the entire geometry and the mass and volume of the material used to build the safety berm alongside the speed and approach conditions of the machinery.The findings of the study enable operators to set speed limits based on specific berm geometries or adapt safety berm designs to match speed constraints for specific machinery.This will reduce the risk of fatal accidents and improve haul road safety.
基金Supported by Scientific Research Project of China Rehabilitation Research Center:2006-23
文摘Objective To observe the effect of acupuncture combined with speech therapy on dysarthria after stroke or cerebral trauma. Methods Sixty-one cases of dysarthria were randomly divided into two groups. The observation group （30 cases） was treated with speech therapy and acupuncture at major acupoints Lianquan （廉泉 CV 23）, Jinjin （金津 EX-HN 12）, Yuye （玉夜 EX-HN 13）, Fengchi（风池 GB 20）, Yifeng （翳风 TE 17） and Wangu（完骨 GB 12）, and the control group （31 cases） was treated with speech therapy only. The changes of speech and acoustical indices were evaluated after 9 weeks treatment. Results The word articulation and the correct rate of writings in the two groups were significantly increased after treatment （both P〈0.01）. The total effective rate of 96.7%（29/30） in the observation group was superior to that of 67.7%（21/31） in the control group （P〈0.01）. The maximum phonation time （MPT） tested by a phonolaryngeal aeromechanical analyzer was significantly prolonged in both the observation group （12 cases） and the control group （11 cases） （both P〈0.01）, the improvement in the observation group being more obvious （P〈0.01）. Conclusion Acupuncture combined with speech therapy can improve the speech and acoustic level in the patient of dysarthria.
文摘Superplasticity of AZ 31 magnesium matrix composites reinforced with 10 vol% SiC（2 μm） particulate i s investigated at temperature range from 365℃ to 565℃ and strain rate from 2.0 8×10<sup>-3</sup> to 5.21×10<sup>-1</sup> s<sup>-1</sup>. The maximum total elongation of 228 % is obtained at a strain rate of 2.08×10<sup>-1</sup> s<sup>-1</sup>. The strain rate se nsitivity exponent （m） higher than 0.3, is observed when the strain rate is high er than 10<sup>-1</sup> s<sup>-1</sup> at 525℃. Increasing the test temperature to 540℃, the maximum total elongation exceeding 195% is achieved at a higher strain rate of 5.21×10<sup>-1</sup> s<sup>-1</sup> than that at 525℃. SiC in AZ31/SiCp composite ca n fine the matrix grain size. Filament is observed on the fracture surface of th e specimens showing superplasticity.
文摘目前Microsoft Power Point(PPT)在多媒体课件制作软件中占据了主导地位,但PPT课件用在基于网络化、数字化的教学中有着先天性不足。文章从多媒体元素、PPT兼容、平台(Flash vs Html 5)、技术的可用性和技术的教学性五个方面对基于PPT扩展应用的三款主流快速课件制作工具(Articulate Studio 13、i Spring Presenter 7、Adobe Presenter 9)进行了横向对比,分析了其制作网络化多媒体课件的优势,总结了快速课件制作的发展趋势,以期为创建适用于网络化、数字化教学需求的多媒体课件提供借鉴。
基金The National Natural Science Foundation of China(No.60443007,50390063).
文摘A principal component analysis-cerebellar model articulation controller （PCA-CMAC） model is proposed for machine performance degradation assessment.PCA is used to feature selection,which eliminates the redundant information among the features from the sensor signals and reduces the dimension of the input to CMAC.CMAC is used to assess degradation states quantitatively based on its local generalization ability.The implementation of the model is presented and the model is applied in a drilling machine to assess the states of the cutting tool. The results show that the model can assess the wear states quantitatively based on the normal state of the cutting tool.The influence of the quantization parameter g and the generalization parameter r in the CMAC model on the assessment results is analyzed.If g is larger,the generalization ability is better,but the difference of degradation states is not obvious.If r is smaller,the different states are distinct,but memory requirements for storing the weights are larger.The principle for selecting two parameters is that the memory storing the weights should be small while the degradation states should be easily distinguished.
基金supported by National Basic Research Program of China(973 Program, Grant No. 2013CB035502)International Science and Technology Cooperation Project with Russia (Grant No. 2010DFR70270)+2 种基金National Natural Science Foundation of China (Grant No. 51275106)"111" Project (Grant No. B07018)Key Laboratory Opening Funding of Aerospace Mechanism and Control, China (Grant No. HIT. KLOF.2010057)
文摘The accuracy of an articulated torque analysis influences the comprehensive performances of heavy-duty multi-legged robots. Currently, the extremal estimation method and some complex methods are employed to calculate the articulated torques, which results in a large safety margin or a large number of calculations. To quickly obtain accurate articulated torques, an analysis method for the articulated torque is presented for an electrically driven heavy-duty six-legged robot. First, the rearmost leg that experiences the maximum normal contact force is confirmed when the robot transits a slope. Based on the ant-type and crab-type tripod gaits, the formulas of classical mechanics and MATLAB software are employed to theoretically analyze the relevant static torques of the joints. With the changes in the joint angles for the abductor joint, hip joint, and knee joint, variable tendency charts and extreme curves are obtained for the static articulated torques. Meanwhile, the maximum static articulated torques and the corresponding poses of the robot are also obtained. According to the poses of the robot under the maximum static articulated torques, ADAMS software is used to carry out a static simulation analysis. Based on the relevant simulation curves of the articulated torques, the maximum static articulated torques are acquired. A comparative analysis of the maximum static articulated torques shows that the theoretical calculation values are higher than the static simulation values, and the maximum error value is approximately 10%. The proposed method lays a foundation for quickly determining accurate articulated torques to develop heavy-duty six-legged robots.
基金the Fundamental Research Funds for the Central Universities of China(No.FRF-TP-15-023A1)the National Key R&D Program Project(Nos.2016YFC0802905 and 2018YFC0604403)
文摘This paper designs a novel controller to improve the path-tracking performance of articulated dump truck(ADT). By combining linear quadratic regulator(LQR) with genetic algorithm(GA), the designed controller is used to control linear and angular velocities on the midpoint of the front frame. The novel controller based on the error dynamics model is eventually realized to track the path high-precisely with constant speed. The results of simulation and experiment show that the LQR-GA controller has a better tracking performance than the existing methods under a low speed of 3 m/s. In this paper, kinematics model and simulation control models based on co-simulation of ADAMS and Matlab/Simulink are established to verify the proposed strategy. In addition, a real vehicle experiment is designed to further more correctness of the conclusion. With the proposed controller and considering the steering model in the simulation, the control performance is improved and matches the actual situation better. The research results contribute to the development of automation of ADT.
