This paper presents a novel five degrees of freedom (DOF) two-wheeled robotic machine (TWRM) that delivers solutions for both industrial and service robotic applications by enlarging the vehicle′s workspace and incre...This paper presents a novel five degrees of freedom (DOF) two-wheeled robotic machine (TWRM) that delivers solutions for both industrial and service robotic applications by enlarging the vehicle′s workspace and increasing its flexibility. Designing a two-wheeled robot with five degrees of freedom creates a high challenge for the control, therefore the modelling and design of such robot should be precise with a uniform distribution of mass over the robot and the actuators. By employing the Lagrangian modelling approach, the TWRM′s mathematical model is derived and simulated in Matlab/Simulink?. For stabilizing the system′s highly nonlinear model, two control approaches were developed and implemented: proportional-integral-derivative (PID) and fuzzy logic control (FLC) strategies. Considering multiple scenarios with different initial conditions, the proposed control strategies′ performance has been assessed.展开更多
This paper proposes an adaptive nonlinear proportional-derivative(ANPD)controller for a two-wheeled self-balancing robot(TWSB)modeled by the Lagrange equation with external forces.The proposed control scheme is design...This paper proposes an adaptive nonlinear proportional-derivative(ANPD)controller for a two-wheeled self-balancing robot(TWSB)modeled by the Lagrange equation with external forces.The proposed control scheme is designed based on the combination of a nonlinear proportional-derivative(NPD)controller and a genetic algorithm,in which the proportional-derivative(PD)parameters are updated online based on the tracking error and the preset error threshold.In addition,the genetic algorithm is employed to adaptively select initial controller parameters,contributing to system stability and improved control accuracy.The proposed controller is basic in design yet simple to implement.The ANPD controller has the advantage of being computationally lightweight and providing high robustness against external forces.The stability of the closed-loop system is rigorously analyzed and verified using Lyapunov theory,providing theoretical assurance of its robustness.Simulations and experimental results show that the TWSB robot with the proposed ANPD controller achieves quick balance and tracks target values with very small errors,demonstrating the effectiveness and performance of the proposed controller.The proposed ANPD controller demonstrates significant improvements in balancing and tracking performance for two-wheeled self-balancing robots,which has great applicability in the field of robot control systems.This represents a promising solution for applications requiring precise and stable motion control under varying external conditions.展开更多
This study mainly concerns a motion model and the main control algorithm of two-wheel self-balancing vehicle models.Details of the critical parameters fetching and output value of two-wheel self-balancing vehicle mode...This study mainly concerns a motion model and the main control algorithm of two-wheel self-balancing vehicle models.Details of the critical parameters fetching and output value of two-wheel self-balancing vehicle models are introduced,including those concerning balance control,speed control and direction control.An improved cascade coupling control scheme is proposed for two-wheel vehicles,based on a proportional-integral-derivative(PID)control algorithm.Moreover,a thorough comparison between a classic control system and the improved system is provided,and all aspects thereof are analyzed.It is determined that the control performance of the two-wheel self-balancing vehicle system based on the PID control algorithm is reliable,enabling the vehicle body to maintain balance while moving smoothly along a road at a fast average speed with better practical per-formance.展开更多
Based on the study on the city transport systems of some typical cities worldwide,this paper put forward that each city transport system has its own development mode,which is influenced by the city development plan,ec...Based on the study on the city transport systems of some typical cities worldwide,this paper put forward that each city transport system has its own development mode,which is influenced by the city development plan,economic development level,traveling vehicle composition etc..When some problems occur,such as the congestions caused by contradiction between the road capacity and vehicle composition,the city transport system may come into temporary maturity period.If the improvement for road system is limited meanwhile,optimized structure of vehicle composition should be an effective solution in this case.With the development of economy-internationalization,the development speed of city transport modernization is rapid.When traveling easiness is conflicting with efficiency,the advantages of public transport system become more obvious.Correspondingly,the superiority of two-wheel vehicles will reappear.Though the important function of two-wheel vehicles for alleviating city traffic problems is obvious,however,their development strategy must be reasonably proposed,and operation regulations must be performed accordingly.展开更多
A novel motor learning method is present based on the cooperation of the cerebellum and basal ganglia for the behavior learning of agent. The motor learning method derives from the principle of CNS and operant learnin...A novel motor learning method is present based on the cooperation of the cerebellum and basal ganglia for the behavior learning of agent. The motor learning method derives from the principle of CNS and operant learning mechanism and it depends on the interactions between the basal ganglia and cerebellum. The whole learning system is composed of evaluation mechanism, action selection mechanism, tropism mechanism. The learning signals come from not only the Inferior Olive but also the Substantia Nigra in the beginning. The speed of learning is increased as well as the failure time is reduced with the cerebellum as a supervisor. Convergence can be guaranteed in the sense of entropy. With the proposed motor learning method, a motor learning system for the self-balancing two-wheeled robot has been built using the RBF neural networks as the actor and evaluation function approximator. The simulation experiments showed that the proposed motor learning system achieved a better learning effect, so the motor learning based on the coordination of cerebellum and basal ganglia is effective.展开更多
With the development of economy and society,China’s comprehensive national strength has been continuously enhanced and its international influence has been increasing.China is shouldering more international responsib...With the development of economy and society,China’s comprehensive national strength has been continuously enhanced and its international influence has been increasing.China is shouldering more international responsibilities and obligations to make greater contributions to building a community of shared future for mankind by“always being a builder of world peace,a contributor to global development,and a defender of the international order”.In March 2015,President Xi Jinping put forward the concept of the Belt and Road Initiative,which not only pointed out the way for Chinese social organizations to participate in international affairs,but also opened up unprecedented opportunities for Chinese social organizations to further participate in global governance.展开更多
Predicting of repair and maintenance （R＆M） costs of tractors in any mechanized farm is necessary for owners and managers to obtain information on overall costs and to control financial balance and production econom...Predicting of repair and maintenance （R＆M） costs of tractors in any mechanized farm is necessary for owners and managers to obtain information on overall costs and to control financial balance and production economy. In this context a study was conducted to predict accumulated R＆M costs （Y） of two-wheel drive （2WD） tractors based on accumulated usage hours （X） in Misagh-e-Sabz Agribusiness Company in Iran. Recorded data of the company were used to determine regression models for predicting accumulated R＆M costs （as percentage of initial purchase price） based on accumulated usage hours. The statistical results of the study indicated that in order to predict accumulated R＆M costs of 2WD tractors with accumulated usage hours of 2260 h or less the power regression model Y=0.013 （X/100）1.677 with R2=0.976, and to predict accumulated R＆M costs of 2WD tractors with accumulated usage hours of 2260 h or more the polynomial regression model Y=0.004 （X/100）2-0.181 （X/1 00）＋4.373 with R2=0.998 can be strongly suggested.展开更多
Yaw rate and sideslip angle are critical indicators for evaluating vehicle handling stability.When a vehicle is driven at high speed,emergency steering by the driver may cause loss of control,leading to severe acciden...Yaw rate and sideslip angle are critical indicators for evaluating vehicle handling stability.When a vehicle is driven at high speed,emergency steering by the driver may cause loss of control,leading to severe accidents such as rollover.This paper establishes a mathematical model of a two-wheel steering system to analyze vehicle handling stability.Using Matlab/Simulink,steady-state response curves under different front-wheel steering angles and speeds are compared to investigate the influence of yaw rate and sideslip angle on vehicle handling stability.展开更多
As per statistics,two-wheeler(TW)alone shares the highest number of vehicle registrations in India,which develops the various transportation-related issues such as traffic conflicts,congestions,and pollutions.Electric...As per statistics,two-wheeler(TW)alone shares the highest number of vehicle registrations in India,which develops the various transportation-related issues such as traffic conflicts,congestions,and pollutions.Electric two-wheelers(E-TW)are a better alternative to conventional two-wheelers because of their significant advantage in mitigating environmental impacts.But E-TWs are less attractive among road users due to unawareness of the benefits of E-TW.In addition,the traditional methods are less accurate in predicting users’mode choice behavior because of their limitations.Therefore,there is a need to conduct a study to understand the road user’s willingness to adopt E-TW and find a suitable method for predicting mode choice behavior accurately.This study analyzes the Indian road users encouraging and discouraging factors to adopt E-TW and investigates the application of non-traditional models for estimating mode shift behaviour towards E-TW.Based on the literature review and expert opinion,a detailed questionnaire form was framed,and a total of 522 samples were collected from four states of India.The data findings show that Indian road users prefer TW compared to public transport,private four-wheeler,paratransit,and non-motorized transport because of its easy to ride,low maintenance,fast and convenient travel nature.The environmental concern of reducing air pollution and lower vehicle operating costs are significant factors that encourage E-TW adoption.However,the non-availability of charging infrastructure,lower speed,higher initial purchase cost,and lack of awareness about EVs are the significant discouraging factors in adopting ETW in India.Further,Machine Learning(ML)methods were adopted to predict the mode shift behaviour from the fuel based TW to E-TW,and the results were compared with the Binary Logit(BL)method.The model results indicated that Support vector machine predicted the mode shift behavior with the highest accuracy rate compared with other methods such as Artificial Neural Network,K-Nearest Neighbor,Random Forest,and BL.The outcome of this study would help the transportation planner,EV manufacturers,researchers,and policymakers to understand the Indian user’s preference to adopt E-TW.展开更多
Conservation agriculture(CA)based production systems may help in achieving more sustainable intensification of cropping systems that use less labour and energy and have higher profit margins,in addition to soil conser...Conservation agriculture(CA)based production systems may help in achieving more sustainable intensification of cropping systems that use less labour and energy and have higher profit margins,in addition to soil conservation and environmental impact mitigation advantages.But these objectives can only be achieved when the right mechanization options,including appropriate crop establishment equipment,are in place to assist in timely field operations.An urgent need exists,therefore,to fine tune and re-adjust the existing two-wheel tractor(2WT)operated seed drills,with specific reference to the design of blade and furrow openers,while at the same time considering performance in different soil types and environments.To this end,experiments were conducted during 2013-2014 and 2014-2015 at two BARI Regional Agricultural Research Stations in Jamalpur and Barisal,Bangladesh,on a loam and clay loam soil,respectively,to evaluate five types of furrow opener for strip tillage.Shoe and modified shoe-type furrow openers were tested and compared with three inverted-T furrow openers with rake angles of 75°,65°and 55°.The newly designed inverted-T furrow openers were narrower than the shoe-type openers;they also had a longer,hollow shanks and provided better options for adjustment to achieve the desired seeding depth and line spacing.Compared to shoe-type openers,better seeding depth,uniformity and higher degree of seed coverage were recorded with use of the inverted-T furrow opener with a 65°rake angle.This resulted in better seed coverage in the furrow,a higher emergence rate index,and the highest emergence percentage of maize and mung bean.Our research findings can be generalized to smallholder production systems on loam and clay loam soils where farmers utilize 2WT operated seed drills for crop establishment in both traditional and conservation agriculture-based planting systems.展开更多
This paper presents a comprehensive techno-economic and environmental impact analysis of electric two-wheeler batteries in India.The technical comparison reveals that sodium-ion(Na-ion)and lithium-ion(Li-ion)batteries...This paper presents a comprehensive techno-economic and environmental impact analysis of electric two-wheeler batteries in India.The technical comparison reveals that sodium-ion(Na-ion)and lithium-ion(Li-ion)batteries outperform lead-acid batteries in various parameters,with Na-ion and Li-ion batteries exhibiting higher energy densities,higher power densities,longer cycle lives,faster charge rates,better compactness,lighter weight and lower self-discharge rates.In economic comparison,Na-ion batteries were found to be~12-14%more expensive than Li-ion batteries.However,the longer lifespans and higher energy densities of Na-ion and Li-ion batteries can offset their higher costs through improved performance and long-term savings.Lead-acid batteries have the highest environmental impact,while Li-ion batteries demonstrate better environmental performance and potential for recycling.Na-ion batteries offer promising environmental advantages with their abundance,lower cost and lower toxic and hazardous material content.Efficient recycling processes can further enhance the environmental benefits of Na-ion batteries.Overall,this research examines the potential of Na-ion batteries as a cheaper alternative to Li-ion batteries,considering India’s abundant sodium resources in regions such as Rajasthan,Chhattisgarh,Jharkhand and others.展开更多
To improve the traffic safety of electric two-wheelers(ETW),China has promulgated ETW standardization policies.This policy requires local governments to take measures to guide the illegal ETWs out of use.Governments h...To improve the traffic safety of electric two-wheelers(ETW),China has promulgated ETW standardization policies.This policy requires local governments to take measures to guide the illegal ETWs out of use.Governments have implemented a depreciation subsidy scheme to encourage users to scrap illegal ETWs early.When designing the subsidy scheme,effectively improving the ETWs’traffic safety at the road network level while saving government expenses is essential for the sustainable implementation of the policy.This study proposes an optimization method for depreciation subsidy design incorporating traffic safety evaluation.Based on the policy scheme,this study formulates a risk assessment model for the ETW traffic network to characterize the effect of the subsidy on improving safety.Then,we use the bi-level programming approach to model the subsidy strategy design problem.The upper-level problem reflects the goal of policymakers to maximize safety improvement and minimize government expenses.The lower-level problem describes the route choices of ETW users.The optimal subsidy design under different safety-expense trade-offs is analysed based on the Nguyen and Dupuis network and a real network extracted from Changsha City in China.The results show that specific subsidy schemes effectively improve road safety without a large government spending.When themarket price or service life of ETWs increases,the government spending on the same safety goal increases.The government should comprehensively consider the safety effect of financial expense and the situation of the local ETW market before selecting reasonable subsidy strategies.展开更多
文摘This paper presents a novel five degrees of freedom (DOF) two-wheeled robotic machine (TWRM) that delivers solutions for both industrial and service robotic applications by enlarging the vehicle′s workspace and increasing its flexibility. Designing a two-wheeled robot with five degrees of freedom creates a high challenge for the control, therefore the modelling and design of such robot should be precise with a uniform distribution of mass over the robot and the actuators. By employing the Lagrangian modelling approach, the TWRM′s mathematical model is derived and simulated in Matlab/Simulink?. For stabilizing the system′s highly nonlinear model, two control approaches were developed and implemented: proportional-integral-derivative (PID) and fuzzy logic control (FLC) strategies. Considering multiple scenarios with different initial conditions, the proposed control strategies′ performance has been assessed.
文摘This paper proposes an adaptive nonlinear proportional-derivative(ANPD)controller for a two-wheeled self-balancing robot(TWSB)modeled by the Lagrange equation with external forces.The proposed control scheme is designed based on the combination of a nonlinear proportional-derivative(NPD)controller and a genetic algorithm,in which the proportional-derivative(PD)parameters are updated online based on the tracking error and the preset error threshold.In addition,the genetic algorithm is employed to adaptively select initial controller parameters,contributing to system stability and improved control accuracy.The proposed controller is basic in design yet simple to implement.The ANPD controller has the advantage of being computationally lightweight and providing high robustness against external forces.The stability of the closed-loop system is rigorously analyzed and verified using Lyapunov theory,providing theoretical assurance of its robustness.Simulations and experimental results show that the TWSB robot with the proposed ANPD controller achieves quick balance and tracks target values with very small errors,demonstrating the effectiveness and performance of the proposed controller.The proposed ANPD controller demonstrates significant improvements in balancing and tracking performance for two-wheeled self-balancing robots,which has great applicability in the field of robot control systems.This represents a promising solution for applications requiring precise and stable motion control under varying external conditions.
基金the National Natural Science Foundation of China(No.61375086)the Key Project of Science and Technique Plan of Beijing Municipal Commission of Education(No.KZ201210005001)+1 种基金the National Basic Research Program(973)of China(No.2012CB720000)the China Scholarship Council Program(No.201406540017)
文摘This study mainly concerns a motion model and the main control algorithm of two-wheel self-balancing vehicle models.Details of the critical parameters fetching and output value of two-wheel self-balancing vehicle models are introduced,including those concerning balance control,speed control and direction control.An improved cascade coupling control scheme is proposed for two-wheel vehicles,based on a proportional-integral-derivative(PID)control algorithm.Moreover,a thorough comparison between a classic control system and the improved system is provided,and all aspects thereof are analyzed.It is determined that the control performance of the two-wheel self-balancing vehicle system based on the PID control algorithm is reliable,enabling the vehicle body to maintain balance while moving smoothly along a road at a fast average speed with better practical per-formance.
文摘Based on the study on the city transport systems of some typical cities worldwide,this paper put forward that each city transport system has its own development mode,which is influenced by the city development plan,economic development level,traveling vehicle composition etc..When some problems occur,such as the congestions caused by contradiction between the road capacity and vehicle composition,the city transport system may come into temporary maturity period.If the improvement for road system is limited meanwhile,optimized structure of vehicle composition should be an effective solution in this case.With the development of economy-internationalization,the development speed of city transport modernization is rapid.When traveling easiness is conflicting with efficiency,the advantages of public transport system become more obvious.Correspondingly,the superiority of two-wheel vehicles will reappear.Though the important function of two-wheel vehicles for alleviating city traffic problems is obvious,however,their development strategy must be reasonably proposed,and operation regulations must be performed accordingly.
文摘A novel motor learning method is present based on the cooperation of the cerebellum and basal ganglia for the behavior learning of agent. The motor learning method derives from the principle of CNS and operant learning mechanism and it depends on the interactions between the basal ganglia and cerebellum. The whole learning system is composed of evaluation mechanism, action selection mechanism, tropism mechanism. The learning signals come from not only the Inferior Olive but also the Substantia Nigra in the beginning. The speed of learning is increased as well as the failure time is reduced with the cerebellum as a supervisor. Convergence can be guaranteed in the sense of entropy. With the proposed motor learning method, a motor learning system for the self-balancing two-wheeled robot has been built using the RBF neural networks as the actor and evaluation function approximator. The simulation experiments showed that the proposed motor learning system achieved a better learning effect, so the motor learning based on the coordination of cerebellum and basal ganglia is effective.
文摘With the development of economy and society,China’s comprehensive national strength has been continuously enhanced and its international influence has been increasing.China is shouldering more international responsibilities and obligations to make greater contributions to building a community of shared future for mankind by“always being a builder of world peace,a contributor to global development,and a defender of the international order”.In March 2015,President Xi Jinping put forward the concept of the Belt and Road Initiative,which not only pointed out the way for Chinese social organizations to participate in international affairs,but also opened up unprecedented opportunities for Chinese social organizations to further participate in global governance.
文摘Predicting of repair and maintenance （R＆M） costs of tractors in any mechanized farm is necessary for owners and managers to obtain information on overall costs and to control financial balance and production economy. In this context a study was conducted to predict accumulated R＆M costs （Y） of two-wheel drive （2WD） tractors based on accumulated usage hours （X） in Misagh-e-Sabz Agribusiness Company in Iran. Recorded data of the company were used to determine regression models for predicting accumulated R＆M costs （as percentage of initial purchase price） based on accumulated usage hours. The statistical results of the study indicated that in order to predict accumulated R＆M costs of 2WD tractors with accumulated usage hours of 2260 h or less the power regression model Y=0.013 （X/100）1.677 with R2=0.976, and to predict accumulated R＆M costs of 2WD tractors with accumulated usage hours of 2260 h or more the polynomial regression model Y=0.004 （X/100）2-0.181 （X/1 00）＋4.373 with R2=0.998 can be strongly suggested.
文摘Yaw rate and sideslip angle are critical indicators for evaluating vehicle handling stability.When a vehicle is driven at high speed,emergency steering by the driver may cause loss of control,leading to severe accidents such as rollover.This paper establishes a mathematical model of a two-wheel steering system to analyze vehicle handling stability.Using Matlab/Simulink,steady-state response curves under different front-wheel steering angles and speeds are compared to investigate the influence of yaw rate and sideslip angle on vehicle handling stability.
文摘As per statistics,two-wheeler(TW)alone shares the highest number of vehicle registrations in India,which develops the various transportation-related issues such as traffic conflicts,congestions,and pollutions.Electric two-wheelers(E-TW)are a better alternative to conventional two-wheelers because of their significant advantage in mitigating environmental impacts.But E-TWs are less attractive among road users due to unawareness of the benefits of E-TW.In addition,the traditional methods are less accurate in predicting users’mode choice behavior because of their limitations.Therefore,there is a need to conduct a study to understand the road user’s willingness to adopt E-TW and find a suitable method for predicting mode choice behavior accurately.This study analyzes the Indian road users encouraging and discouraging factors to adopt E-TW and investigates the application of non-traditional models for estimating mode shift behaviour towards E-TW.Based on the literature review and expert opinion,a detailed questionnaire form was framed,and a total of 522 samples were collected from four states of India.The data findings show that Indian road users prefer TW compared to public transport,private four-wheeler,paratransit,and non-motorized transport because of its easy to ride,low maintenance,fast and convenient travel nature.The environmental concern of reducing air pollution and lower vehicle operating costs are significant factors that encourage E-TW adoption.However,the non-availability of charging infrastructure,lower speed,higher initial purchase cost,and lack of awareness about EVs are the significant discouraging factors in adopting ETW in India.Further,Machine Learning(ML)methods were adopted to predict the mode shift behaviour from the fuel based TW to E-TW,and the results were compared with the Binary Logit(BL)method.The model results indicated that Support vector machine predicted the mode shift behavior with the highest accuracy rate compared with other methods such as Artificial Neural Network,K-Nearest Neighbor,Random Forest,and BL.The outcome of this study would help the transportation planner,EV manufacturers,researchers,and policymakers to understand the Indian user’s preference to adopt E-TW.
基金The authors gratefully acknowledge the USAID Feed the Future Bangladesh supported Cereal Systems Initiative for South Asia (CSISA-BD), and the CSISA Phase III project supported by USAID Washington and the Bill and Melinda Gates Foundation (BMGF) for funding this researchAdditional support was provided by the Bangladesh Agricultural Research Institute (BARI) to support the lead author’s PhD research.
文摘Conservation agriculture(CA)based production systems may help in achieving more sustainable intensification of cropping systems that use less labour and energy and have higher profit margins,in addition to soil conservation and environmental impact mitigation advantages.But these objectives can only be achieved when the right mechanization options,including appropriate crop establishment equipment,are in place to assist in timely field operations.An urgent need exists,therefore,to fine tune and re-adjust the existing two-wheel tractor(2WT)operated seed drills,with specific reference to the design of blade and furrow openers,while at the same time considering performance in different soil types and environments.To this end,experiments were conducted during 2013-2014 and 2014-2015 at two BARI Regional Agricultural Research Stations in Jamalpur and Barisal,Bangladesh,on a loam and clay loam soil,respectively,to evaluate five types of furrow opener for strip tillage.Shoe and modified shoe-type furrow openers were tested and compared with three inverted-T furrow openers with rake angles of 75°,65°and 55°.The newly designed inverted-T furrow openers were narrower than the shoe-type openers;they also had a longer,hollow shanks and provided better options for adjustment to achieve the desired seeding depth and line spacing.Compared to shoe-type openers,better seeding depth,uniformity and higher degree of seed coverage were recorded with use of the inverted-T furrow opener with a 65°rake angle.This resulted in better seed coverage in the furrow,a higher emergence rate index,and the highest emergence percentage of maize and mung bean.Our research findings can be generalized to smallholder production systems on loam and clay loam soils where farmers utilize 2WT operated seed drills for crop establishment in both traditional and conservation agriculture-based planting systems.
文摘This paper presents a comprehensive techno-economic and environmental impact analysis of electric two-wheeler batteries in India.The technical comparison reveals that sodium-ion(Na-ion)and lithium-ion(Li-ion)batteries outperform lead-acid batteries in various parameters,with Na-ion and Li-ion batteries exhibiting higher energy densities,higher power densities,longer cycle lives,faster charge rates,better compactness,lighter weight and lower self-discharge rates.In economic comparison,Na-ion batteries were found to be~12-14%more expensive than Li-ion batteries.However,the longer lifespans and higher energy densities of Na-ion and Li-ion batteries can offset their higher costs through improved performance and long-term savings.Lead-acid batteries have the highest environmental impact,while Li-ion batteries demonstrate better environmental performance and potential for recycling.Na-ion batteries offer promising environmental advantages with their abundance,lower cost and lower toxic and hazardous material content.Efficient recycling processes can further enhance the environmental benefits of Na-ion batteries.Overall,this research examines the potential of Na-ion batteries as a cheaper alternative to Li-ion batteries,considering India’s abundant sodium resources in regions such as Rajasthan,Chhattisgarh,Jharkhand and others.
基金National Natural Science Foundation of China(Grant No.71971222).
文摘To improve the traffic safety of electric two-wheelers(ETW),China has promulgated ETW standardization policies.This policy requires local governments to take measures to guide the illegal ETWs out of use.Governments have implemented a depreciation subsidy scheme to encourage users to scrap illegal ETWs early.When designing the subsidy scheme,effectively improving the ETWs’traffic safety at the road network level while saving government expenses is essential for the sustainable implementation of the policy.This study proposes an optimization method for depreciation subsidy design incorporating traffic safety evaluation.Based on the policy scheme,this study formulates a risk assessment model for the ETW traffic network to characterize the effect of the subsidy on improving safety.Then,we use the bi-level programming approach to model the subsidy strategy design problem.The upper-level problem reflects the goal of policymakers to maximize safety improvement and minimize government expenses.The lower-level problem describes the route choices of ETW users.The optimal subsidy design under different safety-expense trade-offs is analysed based on the Nguyen and Dupuis network and a real network extracted from Changsha City in China.The results show that specific subsidy schemes effectively improve road safety without a large government spending.When themarket price or service life of ETWs increases,the government spending on the same safety goal increases.The government should comprehensively consider the safety effect of financial expense and the situation of the local ETW market before selecting reasonable subsidy strategies.
