摘 要:針對液壓六自由度並聯機構,採用AMESim和Simulink分別對單缸液壓系統及平台機構部分建模,建立並聯機構的通用模擬模型,在AMESim模型中單缸系統的等效負載為Simulink模型反饋的負載力而非等效質量,聯合模擬模型詳細考慮了液壓系統,保證了系統的精度,為研究液壓並聯機構提供了便捷的理論分析手段,通過聯合模擬模型研究了並聯機構由於液壓缸不一致帶來的耦合特性,數值模擬結果表明,當液壓缸性能不一致時會出現耦合現象,耦合度隨著液壓缸性能不一致程度的增大而增強,在並聯機構設計時,必須保證液壓缸性能的一致性。
關鍵詞:六自由度並聯機構;模擬模型;動態耦合
Abstract: A novel universal simulation model of hydraulic six-degree of freedom parallel mechanism was presented, in which the hydraulic actuator servo system was built in the AMESim, and the parallel mechanism part was built in the Simulink. In the AMESim model, the equivalent load of hydraulic actuator is from zhe Simulink model instead of equivalent mass. The combined simulation model takes the details of hydraulic system into consideration to ensure the accuracy, and provides a convenient research technique for hydraulic parallelmechanism. The coupling characteristic of the parallel mechanism was studied through analyzing the dynamic consistency of six actuators using the simulation model. The results show that coupling phenomena appear when the frequency responses of the six actuators were different, and the coupling becomes stronger when the difference among the actuators increases. Thus the dynamic consistency of all actuators must be ensured during the design of parallel mechanism.
Key words: six-degree of freedom parallel mechanism; simulation model; dynamic coupling
相對於傳統的機構,Stewart[1]提出的六自由度空間並聯機構具有結構鋼度大、承載能力強、位置精度高、響應快等優點,因此得到了廣泛應用,但是由於該機構的非線性因素以及強耦合性,機構和控制系統的設計成為難點[2-3],因此機構耦合方面的研究越來越多,例如,在變軸數控機床設計中必須考慮機構的非線性耦合因素[4],空間飛行器為保證飛行品質必須加入耦合控制[5],在平台標定中也需要考慮耦合因素[6]等。