单向共享汽车系统的灵活还车策略

为解决单向共享汽车系统中用户无车位可还车的问题, 提出2种灵活还车策略, 分别是临时车位和空余车位还车策略。前者允许用户将车辆停放在还车站点处由企业租赁的临时车位处; 后者允许用户将车辆停放在与还车站点同区域其余站点的空余车位上。并以最大化企业利润为优化目标, 构建了混合整数非线性规划模型, 用大M法将非线性约束转为线性约束, 采用精确求解软件进行求解。结果表明: 用户还车到临时车位还车和空余车位均可为企业带来利润提升, 最高利润提升比例分别为25%和37%。当且仅当供小于需时, 空余车位还车策略的利润提升效果最佳; 而在同样的供需条件下, 企业租赁的临时车位越多, 临时车位还车策略带来的收益越大。 

Flexible Returning/Parking Strategies for One-way Car-sharing Systems

In one-way car-sharing systems, there are not enough parking places for users to return cars in many cases. Two flexible returning/parking strategies are proposed to solve this problem: parking cars in temporary spaces and unoccupied spaces. In the former strategy, users are allowed to return cars to temporary parking spaces nearest to the car-returning stations. In the latter one, users are encouraged to park cars in available spots in the same zone as the car-returning stations. A mixed-integer nonlinear programming model is developed to maximize the profit of car-sharing companies. The big-M method is applied to convert the nonlinear constraints into linear constraints, and the commercial solver is used to solve the transformed model. A case study shows that parking in temporary spaces and unoccupied spaces can improve the profits of car-sharing companies. The maximal profit increasing rates are 25% and 37%, respectively. When the number of parking spaces is lower than demands, parking to temporary spaces performs well in improving the profits. Under the same circumstance, the more temporary parking spaces the company rent, the higher profits the company can obtain.