Nonlinear Model Predictive Control (NMPC) method-based motion control has attracted considerable attention in the field of autonomous driving. However, the steady-state error problem has not been comprehensively investigated, especially for nonlinear MPC. This paper seeks to solve the steady-state error problem based on Offset-Free NMPC (OF-NMPC) with a lateral-longitudinal coupling structure. The proposed OF-NMPC uses an Unscented Kalman Filter (UKF) to observe the states and disturbances and incorporates them into the prediction model and reference calculation to eliminate the steady-state error. One of the challenges of OF-NMPC is the need to use optimization methods to obtain reference values, which will obviously increase the considerable computational burden. Based on the appropriate simplification, we get the reference analytical solution without solving nonlinear optimization problems online in real-time. Simulation and real vehicle experiments show that the proposed OF-NMPC can effectively eliminate the steady-state error and improve the system’s dynamic performance.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |