摘要
阀控伺服系统动态响应快、控制精度高,但始终存在大的节流损失。泵控差动缸系统消除了节流损失,需要解决差动缸面积差造成的不对称流量问题。其中,单泵控差动缸系统,结构简单,使用辅助油源平衡不对称流量,但存在压力控制难、系统刚度差等问题;双泵控差动缸系统,匹配双泵排量比和缸两腔面积比平衡不对称流量,需要设计双液压泵协同控制算法。针对上述问题,提出了分腔独立变转速泵控差动缸电液伺服系统,采用两台变转速开式泵分别驱动差动缸两腔,自动适应差动缸不对称流量,不需要额外辅助油源和节流元件。借鉴阀控系统的静压平衡特性,设计了双泵协同控制的总压力策略,使液压缸在动、静态时两腔压力和保持定值,实现系统的预压紧和泄漏补偿,提高了系统刚度。为提高位置阻尼比和稳定性,进一步引入了加速度反馈对系统校正。理论分析和试验结果表明,系统具有好的动、静态特性,在四个象限内具有相同的速度增益,能够四象限驱动负载,仅采用简单的比例控制就能获得高的定位精度,控制特性与阀控系统类似,适用于液压电梯、压力机、注塑成型机等大功率工业设备。
The valve-controlled servo system has fast dynamic response and high control accuracy,but there is always a large throttling loss.The pump-controlled differential cylinder system eliminates throttling losses and needs to solve the problem of asymmetric flow caused by the area difference of differential cylinder.Among them,the single-pump-controlled differential cylinder system has a simple structure and uses an auxiliary oil source to balance asymmetrical flow,but it has problems such as difficult pressure control and poor system stiffness.The double-pump-controlled differential cylinder system matches the displacement of the double pump to balance the asymmetric flow,and a double-pump coordinated control algorithm needs to be designed.For the above problems,the sub-chamber independent variable speed-pumps control differential cylinder principle is proposed.Two variable-speed open-type pumps are used to directly drive the two chambers of the differential cylinder without additional auxiliary oil source and throttling elements.It can adapt to the asymmetric flow caused by any area ratio of differential cylinder automatically.With reference to the static pressure balance characteristics of the valve control system,the sum pressure strategy of dual-pump cooperative control is designed to make the two chambers pressure sum of the hydraulic cylinder keep a constant value in the dynamic and static state,realizing the system pre-compression and leakage compensation,and improving the system stiffness.Further,the acceleration feedback is adopted to enhance system damping ratio and stability.Theoretical analysis and experimental results show that the system has good dynamic and static characteristics and the same speed gain in four quadrants,which can drive loads in four quadrants.Only a simple proportional control is used to achieve high positioning accuracy,and the control characteristics are similar to valve control systems.It’s suitable for hydraulic elevator,press,injection molding machine and other high-power industrial equipment.
作者
王波
郝云晓
权龙
王翔宇
葛磊
赵斌
WANG Bo;HAO Yunxiao;QUAN Long;WANG Xiangyu;GE Lei;ZHAO Bin(College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2020年第18期235-243,共9页
Journal of Mechanical Engineering
基金
国家自然科学基金(51575374,51775363)
山西省重点研发计划(201803D121003)资助项目。
关键词
变转速泵
分腔独立
总压力控制
泵控差动缸
电液伺服系统
variable-speed pump
sub-chamber independent control
total pressure strategy
pump-controlled differential cylinder
electro-hydraulic servo system
