在大型足式机器人的驱动系统中，使用液压柔顺驱动器进行补充能量控制可以极大地提高机器人的续航能力，因此具有很强的实用价值。首先通过扫频的方式分别得到驱动器输出端空载状态位置频率特性曲线和输出端静止状态力频率特性曲线，然后通过MATLAB的ident系统辨识工具箱进行模型辨识得到较准确的驱动器数学模型。基于上述模型采用自抗扰力控制器，实时估计扰动及对其进行有效的补偿，取得了较好的力控制效果，进而通过力控制将液压缸等效为变刚度弹簧。建立液压柔顺驱动器中液压能、驱动器能量和热能三种能量的动态模型，并对简化运动过程中三种能量之间的转换规律进行分析。基于变刚度策略对运动过程进行了补充能量控制，提高了能量使用效率。不同负载质量和不同液压缸刚度情况下的水平方向运动试验结果验证了上述控制策略的有效性。
In the actuation system of large legged robots, the supplementary energy control of hydraulic compliant actuator can greatly improve the robot endurance, which has strong practical value. The displacement frequency characteristic curve without load and force frequency characteristic curve with the fixed output displacement are obtained respectively and firstly by frequency sweep, and then the accurate mathematical model of the actuation system is obtained through the identification toolbox of MATLAB ident. The active disturbance rejection controller is adopted to estimate the perturbation in real-time and compensate the disturbance effectively based on the above mathematical model. A better force control effect is obtained. And then the hydraulic cylinder is equivalent to a variable stiffness spring through the force control. The three energy dynamic models of the hydraulic energy, the energy of the actuator and the heat energy are built for the hydraulic compliant actuator, and the energy conversion law of these three energies is analyzed for the simplified movement. The adjustable stiffness strategy is used to fulfil the supplement energy control during the movement, and the energy efficiency is improved. The experimental results of horizontal motion with different load mass and different stiffness of hydraulic cylinder show the effectiveness of the above control strategy.
[1] PRATT G A,WILLIAMSON M M. Series elastic actuators[C]//Proceedings of the 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Pittsburg,1995:399-406.
[2] VANDERBORGHT B,TSAGARAKIS N G.,SEMINI C,et al. MACCEPA 2.0:Adjustable compliant actuator with stiffening characteristic for energy efficient hopping[C]//Proceedings of 2009 IEEE International Conference on Robotics and Automation. Kobe,2009:544-549.
[3] ROUSE E J,MOONEY L M,MARTINEZ-VILLALPANDO E C,et al. Clutchable series-elastic actuator:design of a robotic knee prosthesis for minimum energy consumption[C]//Proceedings of the 2013 IEEE International Conference on Rehabilitation Robotics. Seattle,2013:1-6.
[4] BHARADWAJ K,SUGAR T G,KOENEMAN J B,et al. Design of a robotic gait trainer using spring over muscle actuators for ankle stroke rehabilitation[J]. Journal of Biomechanical Engineering,2005,127(11):1009-1013.
[5] HAM R V,VANDERBORGHT B,DAMME M V,et al. MACCEPA:The mechanically adjustable compliance and controllable equilibrium position actuator for controlled passive walking[C]//Proceedings of the 2006 IEEE International Conference on Robotics and Automation. Orlando,2006:2195-2200.
[6] VANDERBORGHT B,VERRELST B,HAM R V,et al. Development of a compliance controller to reduce energy consumption for bipedal robots[J]. Auton Robot,2008,24:419-434.
[7] BOAVENTURA T, SEMINI C,BUCHLI J,et al. Dynamic torque control of a hydraulic quadruped robot[C]//Proceedings of 2012 IEEE International Conference on Robotics and Automation. River Centre,2012:1889-1894.
[8] RAGONESI D,AGRAWAL S,SAMPLE W,et al. Series elastic actuator control of a powered exoskeleton[C]//Proceedings of the 33rd Annual International Conference of the IEEE EMBS. Boston,2011:3515-3518.
[9] LAFFRANCHI M,TSAGARAKIS N G,CANNELLA1 F,et al. Antagonistic and series elastic actuators:A comparative analysis on the energy consumption[C]//Proceedings of the 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems. Louis,2009:5678-5684.
[10] GRIMMER M,SEYFARTH A. Stiffness adjustment of a series elastic actuator in a knee prosthesis for walking and running:The trade-off between energy and peak power optimization[C]//Proceedings of the 2011 IEEE/RSI International Conference on Intelligent Robots and Systems. San Francisco,2011:1811-1816.
[11] SANTOS W M,CAURIN G A P,SIQUEIRA A A G,et al. Torque control characterization of a rotary series elastic actuator for knee rehabilitation[C]//Proceedings of 201316th International Conference on Advanced Robotics. Montevideo,2013:1-6.
[12] PALUSKA D,HERR H. Series elasticity and actuator power output[C]//Proceedings of the 2006 IEEE International Conference on Robotics and Automation. Orlando,2006:1830-1833.
[13] KANG B,KOTHERA C S,WOODS B K S,et al. Dynamic modeling of Mckibben pneumatic artificial muscles for antagonistic actuation[C]//Proceedings of the 2009 IEEE International Conference on Robotics and Automation. Kobe,2009:182-187.
[14] ROBINSON D W,PRATT G A. Force controllable hydro-elastic actuator[C]//Proceedings of the 2000 IEEE International Conference on Robotics & Automation. San Francisco,2000:1321-1327.
[15] HYON S,EMURA T. Running control of a planar biped robot based on energy-preserving strategy[C]//Proceedings of the 2004 IEEE International Conference on Robotics & Automation. New Orleans,2004:3791-3796.
[16] CURRAN S,ORIN D E. Evolution of a Jump in an articulated leg with series-elastic actuation[C]//Proceedings of the 2008 IEEE International Conference on Robotics and Automation. Pasadena,2008:352-358.
[17] 韩京清. 自抗扰控制技术[J]. 前沿科学,2007,1(1):24-31. HAN Jingqing. active disturbance rejection control technique[J]. Frontier Science,2007,1(1):24-31.
[18] 韩京清. 自抗扰控制技术-估计补偿不确定性因素的控制技术[M]. 北京市:国防工业出版社,2008. HAN Jingqing. Active disturbance rejection control technique-the technique for estimating and compensating the uncertainties[M]. Beijing:National Defense Industry Press,2008.
[19] 方勇纯,申辉,孙秀云,等. 无人直升机航向自抗扰控制[J]. 控制理论与应用,2014,31(2):238-243. FANG Yongchun,SHEN Hui,SUN Xiuyun,et al. Active disturbance rejection control for heading of unmanned helicopter[J]. Control Theory & Applications,2014,31(2):238-243.
[20] 张立勋,邹宇鹏,隋立明,等.宇航员康复训练机器人自抗扰力控制[J]. 机器人,2012,34(2):217-222. ZHANG Lixun, ZHOU Yupeng, SUI Liming,et al. Active disturbance rejection force control for astronaut rehabilitative training robot[J]. Robot,2012,34(2):217-222.
