Backlash control in automotive powertrain

Transcription

1 Backlash control in automotive powertrain Joonas Sainio School of Electrical Engineering Seminar presentation Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

2 Topics today Agenda briefly: Backlash in powertrains Problems introduced by backlash Backlash compensation methods Backlash controllers Need for backlash estimation Modelling powertrain and backlash Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

3 Automotive powertrain: Lightly damped oscillating system Figure: Basic front-wheel driven powertrain. Source: [1] Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

4 Backlash in powertrain What is backlash in the powertrain? Figure: Backlash in powertrain. Source: [2] Sources: In gears and joints of shafts. Why: Lubrication, manufacturing errors, deflection under load, thermal expansion. Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

5 Problems introduced by backlash Excites oscillations in powertrain (shunt and shuffle phenomenon) Introduces audible noise Driving comfortability decreases Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

6 Problem: Shunt and shuffle Figure: Shunt and shuffle phenomenon. [2] Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

7 Backlash compensation methods Two ways to deal with backlash: Let s use more precise mechanical parts such that backlash doesn t exist Expensive! Let s compensate the backlash by control system Cheaper and more exciting! Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

8 Backlash controllers Controllers can be devided into three categories. 1. Linear controllers 2. Non-linear passive controllers 3. Non-linear active controllers Trade-off has to be done in control system s response and it s robustness. Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

9 Backlash estimators Backlash controllers in literature expect the state of backlash to be known exactly. Need for estimators in real life Estimators based on available measurements in real vehicle Powertrain and backlash models has to be used Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

10 Modelling powertrain and backlash The powertrain can be modelled with multiple rotating masses, springs and dampers. Figure: A powertrain model. Source: [3] Two-mass models, three-mass models... nine-mass models. Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

11 Modelling powertrain and backlash Backlash models are mostly: Traditional dead-zone models Suffer from errors when also a shaft damping is modelled Physically more correct backlash models Allows to simulate the backlash state and remaining shaft twist at the same time Highly recommended model Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

12 Notations Backlash control does reduce the oscillation in powertrains, but does NOT totally remove it! Backlash control should be combined with separate damping control to suppress the oscillations in the powertrain. In electric vehicle powertrains the backlash control can be carried out much more precisely due to fast and precise torque response of electric motors. Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

13 THANK YOU! Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14

14 Figure sources P Borodani and C d Ambrosio. Robust control for active damping of an hybrid vehicle driveline shuffle. In Proceedings of the 10th Mediterranean Conference on Control and Automation-MED2002, Adam Lagerberg. Control and estimation of automotive powertrains with backlash. PhD thesis, Chalmers University of Technology, Peter Templin. Simultaneous estimation of driveline dynamics and backlash size for control design. In Control Applications, CCA IEEE International Conference on, pages IEEE, Joonas Sainio (Aalto-yliopisto) Seminar November 5, / 14