遗传算法在国Ⅵ固定式风速仪行驶阻力测试中的应用

Application of genetic algorithms in running resistance measurements of CHINA 6 stationary anemometry

依据轻型汽车污染物排放限值及测量方法(中国第六阶段)对某乘用车采用固定式风速仪测试法进行道路滑行试验,测试道路行驶阻力,为解决其试验、数据处理过程耗时过长的问题,考虑引入新方法。从理论分析,建立道路行驶阻力数学模型,把求解道路行驶阻力系数转化为函数最值问题。比较、讨论多种算法,结合VMS3200C设备记录的大量有效试验数据,运用最小二乘法的思想,采用遗传算法对超静定方程组及目标函数进行求解,优化迭代,快速有效地得到道路行驶阻力系数最优解;遗传算法与国Ⅵ标准固定式风速仪测试法数据处理结果相对误差在可接受的范围内,特别是取5对滑行试验数据进行计算时,相对误差最小;优化试验方法,两段滑行法代替五段滑行法,可提高试验效率,同时,省去国Ⅵ标准固定式风速仪测试法繁杂的数据验证过程,说明使用遗传算法优化道路行驶阻力测试的可行性较大。

According to limits and measurement methods for emissions from light-duty vehicles(CHINA 6),the stationary anemometry measurement is used to test road running resistance for a passenger car by road coastdown test.In order to solve the problems that the tests and data processing process take too long,a new method is considered.Based on the theoretical analysis,the mathematical model of road running resistance is established,and the solution of road running resistance coefficient is transformed into the maximum or minimum value of function.A variety of algorithms are compared and discussed.Combined with the large amount of effective test data recorded by VMS3200C and the idea of least square method,genetic algorithms are used to solve the statically indeterminate equations and the objective function.Then the optimal solution of road running resistance coefficient is obtained quickly and effectively from optimization and iteration.The relative error between the data processing results of genetic algorithms and CHINA 6 stationary anemometry measurements is within the acceptable range,especially when five parts coastdown test data is taken for calculation,the relative error is the smallest.The test method is optimized,two parts coastdown method replaces the five parts coastdown method,which improves the tests efficiency.Meanwhile,the complicated data validation process from CHINA 6 stationary anemometry measurements is omitted.It shows that it is feasible to use genetic algorithms to optimize road running resistance measurements.