Development of intelligent McKibben actuator

The aim of this study is to develop an intelligent McKibben actuator with an integrated soft displacement sensor inside, so that displacement of this actuator can be controlled without having any extra devices attached. In addition, the high compliance which is a positive feature of the McKibben actuator is still conserved. This paper consists of four main parts. First of all, different types of soft displacement sensors made out of rubber were composed, and tested for their functional characteristics. Secondly, the intelligent McKibben actuator was developed with the soft displacement sensor incorporated within. Then, experiments of the position servo control with a single intelligent McKibben actuator were carried out. At last a robot arm mechanism was designed with two intelligent McKibben actuators, and those experimental results showed a great potential for its future applications.</p

Modeling of a Dynamic McKibben Style Muscle System Using Material Properties

The McKibben style artificial muscle is a type of pneumatic artificial muscle. When the muscle is pressurized a length contraction and contractive force occur. Modeling a McKibben style muscle presents many challenges. The physical dynamics of the muscle are highly nonlinear, which makes accurate modeling difficult. Modeling using experimentally determined coefficients enables the creation of an equation that ignores the nonlinear nature of the system, but it can have a limited range or accuracy and cannot adjust for changing system properties. Modeling using the system properties requires the consideration of the nonlinear dynamics of the muscle; however, it provides the ability to run numeric simulations before constructing muscles. This thesis focused on dynamic modeling of a two muscle system using system properties. In order to develop a two muscle dynamic system model, the following steps were taken. Models using physical properties for individual static muscles were examined. Two muscles were linked around a pulley to form a two muscle system with an output of angular displacement and torque. Finally, the effect of valves was added to allow for modeling of transient system response. In order to validate the model, an experimental system was constructed. The muscle system was simulated using MATLAB and outputs were compared to experimental results. Good agreement between theoretical and experiment results was obtained. A PID controller was then implemented on the new model to demonstrate the feasibility of using the model for control of a two muscle system. The controller was run through an optimization routine to determine the gains which gave the least position error. This work is the first to provide a dynamic model for a system of two of opposed McKibben style muscles based on the physical properties of the muscle system

RESEARCH TOWARDS THE DESIGN OF A NOVEL SMART FLUID DAMPER USING A MCKIBBEN ACTUATOR

Vibration reducing performance of many mechanical systems, decreasing the quality of manufactured products, producing noise, generating fatigue in mechanical components, and producing an uncomfortable environment for human bodies. Vibration control is categorized as: active, passive, or semi-active, based on the power consumption of the control system and feedback or feed forward based on whether sensing is used to control vibration. Semi-active vibration control is the most attractive method; one method of semi-active vibration control could be designed by using smart fluid. Smart fluids are able to modify their effective viscosity in response to an external stimulus such as a magnetic field. This unique characteristic can be utilised to build semi-active dampers for a wide variety of vibration control systems. Previous work has studied the application of smart fluids in semi-active dampers, where the kinetic energy of a vibrating structure can be dissipated in a controllable fashion. A McKibben actuator is a device that consists of a rubber tube surrounded by braided fibre material. It has different advantages over a piston/cylinder actuator such as: a high power to weight ratio, low weight and less cost. Recently McKibben actuator has appeared in some semi-active vibration control devise. This report investigates the possibility of designing a Magnetorheological MR damper that seeks to reduce the friction in the device by integrating it with a McKibben actuator. In this thesis the concept of both smart fluid and McKibben actuator have been reviewed in depth, and methods of modelling and previous applications of devices made using these materials are also presented. The experimental part of the research includes: designing and modelling a McKibben actuator (using water) under static loads, and validating the model experimentally. The research ends by presenting conclusions and future work

Experimental Evaluation of A Cylinder Actuator Control Using McKibben Muscle

There has been an increased interest in applying pneumatic muscle actuator (PMA) in robotic systems because of its low weight and high compliant characteristics. On the other hand, pneumatic muscle actuator (PMA) is gaining attention in robotic applications because of its low weight and high compliant characteristics. It is known that the McKibben muscle is different from the fluidic cylinder actuator in that the cylinder was unstable in its position and in its velocity in an open-loop system unlike the McKibben that is stable in its position. The modeling and control of McKibben muscle as the actuator for the cylinder are crucial because it is known to have non-linear response, hysteresis and small stroke. In this project, a single acting cylinder model which would have uncontrolled extension to push direction by compressed air, is actuated and controlled using a PMA. The system is designed with two 1.3mm-diameter McKibben muscles attached to the cylinder. Open loop control was used and the result shows that the PMA is able to control the cylinder with good performance

Analysis of Nonlinear Behavior in Novel Pneumatic Artificial Muscles

Motivated by the excellent actuator characteristics of pneumatic artificial muscles (PAMs), two novel actuators based on this technology were developed for applications where traditional PAMs are not suitable. The first of these actuators is a miniature PAM that possesses the same operating principle as a full-scale contractile PAM, but with a diameter an order of magnitude smaller. The second actuator, a push-PAM, harnesses the operational characteristics of a contractile PAM, but changes the direction of motion and force with a simple conversion package. Testing on these actuators revealed each PAM's evolution of force with displacement for a range of operating pressures. To address the analysis of the nonlinear response of these PAMs, a nonlinear stress vs. strain model, a hysteresis model, and a pressure deadband were introduced into a previously developed force balance analysis. The refined nonlinear model was shown to reconstruct PAM response with higher accuracy than previously possible

Analysis of a Pneumatic Artificial Muscle and Construction of a Model

The purpose of thesis is to show the result of the analysis Pneumatic Artificial Muscle (PAM). Thus, more information to understand on its behavior in generating force for actuation is obtained. The content of this report consists of few sections such as the introduction, literature review, methodology, result and discussion and conclusion. The introduction part consists of project background and problem statement that discuss PAM behavior while researching about this project. The introduction also discuss about the objective and scope of study which is to analyze the behavior of Pneumatic Muscle by using Finite Element Analysis on ANSYS software. The methodology and project planning is stated to show the flow of the thesis and also the Gantt chart provided shows the working schedule that I follow during all this period of year. The result and discussion shows that the construction of 3D PAM model is mainly consists of flexible, inflatable membrane for which the material type and properties are being specified as neoprene rubber. The result of the model is verified according to the solution obtained from the literature. The thesis is concluded by making an observation towards muscle deformation supported evidence by tables provided by ANSYS software. The deformation of the muscle shows the structural behavior changes after Finite Element Analysis. The PAM expanded with the change in volume and also in diameter. The volume increases while the length decrease when pressure applied