| As one of the frontiers of current vehicle technology research,energy-regenerative active suspension has attracted the attention of many scientific researchers because of its capability of both improving ride comfort and recovering suspension vibration energy.Energy-regenerative actuator is the core technology of energy-regenerative active suspension,and its design needs to take into account suspension comprehensive performance and manufacturing cost.Therefore,this paper proposes a systematic energy-regenerative actuator design method for research object of permanent magnet synchronous motor（PMSM）-ball screw energy-regenerative actuator,and designed a nonlinear control system according to the measured mechanical characteristics of the self-developed prototype.Firstly,determining the lower limit value of the maximum electric control force of the PMSM-ball screw energy-regenerative actuator based on the numerical simulation statistics of the LQG control ideal active suspension control force by using probability and statistics theory,selecting the PMSM and ball screw alternative models,and calculating the maximum electric control force,equivalent inertial mass and service life of each PMSM-ball screw combination are proceed in sequence for the specific nominal working conditions of a specific vehicle.Under the conditions of meeting the requirements of the maximum electric control force and service life,the optimal PMSM-ball screw combination is determined by using the maximum electric control force/equivalent inertial mass.Secondly,manufactured the PMSM-ball screw energy-regenerative actuator based on the optimal PMSM-ball screw combination result,and via electromagnetic dynamic modeling,electrical parameter verifying and mechanical characteristics testing the actuator prototype with the triangular wave and sine wave displacement inputs conducted by varying charge voltage experimental method,the Coulomb damping identification and the equivalent inertial mass verification were carried out by parameters fitting to make the modeling simulation mechanical characteristic curves agree with the measured ones.Thirdly,the nonlinear term was linearized based on the feedforward and feedback linearization method,and the acceleration terms of the sprung and unsprung masses in the active suspension model with the actuator Coulomb friction and equivalent inertial mass was normalized.Aiming at the problem that the suspension comprehensive performance is deteriorated by only using the Z∞aequation to constrain the total control force of the actuator,a dual-constrained H2/H∞controller is designed by add a total control force constraint to the Z2 equation.Finally,besides energy-regenerative analysis,performance comparison among the passive suspension,the unconstrained LQG control active suspension,the conventional H2/H∞control active suspension,and the dual constraints based H2/H∞control active suspension were implemented through numerical simulations.The results show that:compared with the passive suspension,the dual constraints based H2/H∞controller reduced the sprung mass acceleration root mean square and suspension comprehensive performance index by 47.05%and 51.67%respectively,which were just 1.86%and1.34%respectively inferior to the ideal active suspension,and superior to the conventional H2/H∞control active suspension by 19.28%and 11.21%respectively under the design nominal working condition（Class C road with a 72km/h speed）.Moreover,60.82%average power absorbed by the actuator was reclaimed to batteries.By contrast,the average powers consumed by the Coulomb damping and the motor stator resistances just were 18.99%and 20.19%respectively.The research results of this paper can provide theoretical and technical references for the design and manufacture of PMSM-ball screw energy-regenerative active suspensions. |
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