【摘要】 数字液压系统具有控制系统简单、液压系统高度简化等优点，其控制精度高于传统的机液伺服系统、生产成本低于电液伺服系统。数字液压缸作为其技术产物，采用数字脉冲信号(步进电机)进行控制，精度较高，同时对油液的要求低，易于维护和使用，在对稳定性要求较高的航空航天、军工及大型工程等领域备受青睐。文中以内驱内部间接反馈数字液压缸为研究对象，对其稳定性做进一步提升，建立带有动压反馈装置的数字液压缸的模型，通过机理建模推导出其数学模型，并利用AMESim软件进行时频分析。机理模型表明：随着外部载荷干扰力的改变，系统将产生随着外载荷增加而增加的附加阻尼；在相同输入下，时域仿真结果表明：带动压反馈的数字液压缸的阀芯和液压缸活塞运动的波动幅度更小。频域仿真结果表明：两者固有频率相同，但带动压反馈装置的数字液压缸相较于之前阻尼比更大，原数字液压缸系统增益裕度为62.5 dB,添加动压反馈后系统增益裕度为102 dB,由此表明添加动压反馈装置后系统更稳定。更多还原

【Abstract】 The digital hydraulic system has the advantages of simple control system, a highly simplified hydraulic system and higher control accuracy than the traditional hydraulic servo system. The production cost is lower than the electro-hydraulic servo system. Digital hydraulic cylinders use digital pulse signals(stepper motor) to realize high precision, while the requirements for oil is low. They are easy to maintain and use and are favored in the aerospace, military and large engineering fields.In order to improve the stability of internal drive digital hydraulic cylinders with indirect feedback, a digital hydraulic cylinder model with a dynamic pressure feedback device isconstructed. The mathematical model is derived through mechanism modeling, and the time-frequency analysis is carried out by AMESim software. The mechanism model shows that with the change of external load interference force, the system will produce additional damping which increases with the increase of external load. Under the same input, the time domain simulation results show that the spool of the digital hydraulic cylinder driving the pressure feedback and the piston of the hydraulic cylinder have smaller fluctuation amplitude. The frequency domain simulation results show that the natural frequency of the two are the same, but the damping ratio is larger than before, and the gain margin of the original digital hydraulic cylinder system is 62.5 dB. After adding dynamic pressure feedback, the gain margin of the system is 102 dB, which indicates that the system is more stable after adding the dynamic pressure feedback device.更多还原