Under the requirement of the force controller of hydraulic quadruped robots, the goal of this work is to accurately track the force commands at the level of the hydraulic drive unit. The main contribution focuses on the development of a force-controlled compensation scheme, which is specifically aimed at the key issues affecting the hydraulic quadrupedal locomotion. With this idea, based on a P-Q valve-controlled asymmetric cylinder, we first establish a mathematical model for the hydraulic drive unit force control system. With the desired force commands, a force feed-forward algorithm is presented to improve the dynamic performance of the system. Meanwhile, we propose a disturbance compensation algorithm to reduce the influence induced by external disturbances due to foot-ground impacts. Afterwards, combining with a variable gain PI controller, a series of experiments are implemented on a force control performance test platform to verify the proposed scheme. The results demonstrate that the force-controlled compensation scheme has the ability to notably improve the force tracking accuracy, reduce the response time and redundant force.

在液压四足机器人的力控制器的要求下，这项工作的目标是在液压驱动单元的水平上准确跟踪力指令。主要贡献在于开发了一种力控制补偿方案，该方案专门针对影响液压四足运动的关键问题。有了这个想法，我们首先基于PQ阀控制的不对称缸，建立了液压驱动单元力控制系统的数学模型。利用所需的力命令，提出了一种力前馈算法，以改善系统的动态性能。同时，我们提出了一种扰动补偿算法，以减少人为干扰引起的外部干扰的影响。之后，结合可变增益PI控制器，在力控制性能测试平台上进行了一系列实验，以验证所提出的方案。结果表明，力控制补偿方案具有显着提高力跟踪精度，减少响应时间和冗余力的能力。