Robust passive tracking control for an uncertain soft actuator using robust right coprime factorization

Abstract

As a research of human arm activities, the research of soft actuator is one of the important topics in the field of robotics. This article is concerned with the robust passive tracking control for an uncertain soft actuator by robust right coprime factorization (RRCF). First, applying the recursive least squares identification algorithm, the identification of the actuator modeling is studied by which the parameter of radius is estimated by using the experimental data. Second, the passivity of the soft actuator with inflatable rubber tube is discussed; meanwhile, the robustness of the soft actuator is ensured by the designed robust controllers. Third, by combining the RRCF and integral sliding mode control methods, the tracking performance is improved, for the soft actuator with time‐varying radius. Finally, the proposed methods are confirmed by the simulation with experimental data.

Operator-Based Nonlinear Control of Calorimetric System Actuated by Peltier Device

“…Figure 4 shows the proposed nonlinear feedback control system using robust right coprime factorization based on operator theory. The detailed information about operator theory is written in [9][10][11][12][13][14][15][16][17].…”

“…are satisfied, the robust stability of the plant with uncertainty P + ∆P can be guaranteed [9][10][11][12][13][14][15][16][17].…”

“…There are several control methods such as sliding mode control [6] and adaptive control [7,8], but in this paper, the control system is designed based on operator theory as in the previous study. Operator theory [9][10][11][12][13][14][15][16][17] restricts the space of input signals and the output space, so it can be applied not only to linear control systems but also to nonlinear control systems. There are three advantages of using operator theory: first, there is no need to use transfer functions; second, robust stability analysis can be performed even when nonlinear elements are included; and third, it can be extended to multiple input-output systems.…”

“…There are three advantages of using operator theory: first, there is no need to use transfer functions; second, robust stability analysis can be performed even when nonlinear elements are included; and third, it can be extended to multiple input-output systems. The references [9][10][11][12][13][14][15][16][17] are papers on this theory, in which a nonlinear control system is designed based on operator theory. However, the heat transfer inside the Peltier device was not taken into account in the calorimetric measurement system proposed in the previous research.…”

Energy shaping control of underactuated mechanical systems with fluidic actuation

“…Typical examples are hydraulic actuators, which are ubiquitous in tilt trailers, excavators, and cranes, 15,16 and pneumatic actuators, which are commonly employed in factory automation and in lightweight or compliant robots. 17,18 Fluidic actuation typically consists of a pressure source, supply pipes, a control valve, and a pump producing the control action in the form of a flow rate, and a cylinder transferring the forces to the mechanism. In some applications, including hydraulic tilt trailers and cranes, two or more cylinders can be arranged in antagonistic pairs to provide rotational motion while also resulting in redundant actuation.…”