Nonlinear energy-based control of soft continuum pneumatic manipulators
Nonlinear energy-based control of soft continuum pneumatic manipulators
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DOI：
10.1007/s11071-021-06817-1
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发表时间：
2021-09
影响因子：
5.6
通讯作者：
Enrico Franco;Tutla Ayatullah;A. Sugiharto;Arnau Garriga-Casanovas;Vani Virdyawan
中科院分区：
文献类型：
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作者：
Enrico Franco;Tutla Ayatullah;A. Sugiharto;Arnau Garriga-Casanovas;Vani Virdyawan
研究了一类软连续介质气动机械手的基于模型的非线性控制问题，该机械臂由于内腔的加压而弯曲，并在存在扰动的情况下工作。采用端口哈密顿描述闭环系统动力学，包括气动执行机构的压力动态，并用基于能量的方法构造了新的非线性控制律。特别是，针对平面和三维空间中操作的软连续体机械手，给出了一种多步骤设计方法。所得到的非线性控制律与自适应观测器相结合，以补偿未知扰动和模型不确定性的影响。利用Lyapunov方法研究了系统的稳定性条件，并讨论了调节参数的影响。为便于比较，文中还给出了一种用反推方法构造的不同控制律。通过仿真和样机实验验证了该控制策略的有效性。为此，采用了由伺服电机操作的针形阀，而不是更复杂的数字压力调节器。所提出的控制器有效地调节了原型的尖端旋转，同时防止了振动并补偿了扰动的影响，并且与反推方法和PID算法相比具有更好的性能。
This paper investigates the model-based nonlinear control of a class of soft continuum pneumatic manipulators that bend due to pressurization of their internal chambers and that operate in the presence of disturbances. A port-Hamiltonian formulation is employed to describe the closed loop system dynamics, which includes the pressure dynamics of the pneumatic actuation, and new nonlinear control laws are constructed with an energy-based approach. In particular, a multi-step design procedure is outlined for soft continuum manipulators operating on a plane and in 3D space. The resulting nonlinear control laws are combined with adaptive observers to compensate the effect of unknown disturbances and model uncertainties. Stability conditions are investigated with a Lyapunov approach, and the effect of the tuning parameters is discussed. For comparison purposes, a different control law constructed with a backstepping procedure is also presented. The effectiveness of the control strategy is demonstrated with simulations and with experiments on a prototype. To this end, a needle valve operated by a servo motor is employed instead of more sophisticated digital pressure regulators. The proposed controllers effectively regulate the tip rotation of the prototype, while preventing vibrations and compensating the effects of disturbances, and demonstrate improved performance compared to the backstepping alternative and to a PID algorithm.