[Design and Development of Air Muscle Actuated Robotic Arm]

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Acknowledgements

Writing this thesis has been very demanding, challenging and time-consuming, but also remarkable, informative and above all fun. Nevertheless, it feels great to have finally completed my bachelor's or master's thesis and I am now looking forward to a nice relaxing period for recovering. It has been both advantages and drawbacks with the limited amount of earlier research conducted within this area, even though I faced serious troubles but sometimes the advantages of this research luckily were in my favor and have made this research both challenging and interesting. I would like to thank my supervisor _____________, professor at _______________University, who has been great in guiding my through this thesis, helping me through the difficulties I faced during the entire process and motivated me to work hard. Furthermore, I would like to thank all my friends, for their contributions by sharing their perceptions and opinions with me. Above all I would like to thank my family and teachers that provided me with valuable and constructive criticism.

Abstract

Modern industrial robots are designed according to the principal design rules to construct light and stiff. These design rules are not suitable for robots to be used in a domestic environment. Industrial robots are stiff and strong and, for these reasons, dangerous to humans. To allow for robots to be safe in a domestic environment, they need to be compliant. So, in case a domestic robot comes in contact with a human, this does not lead to injuries.

Several options are available to make robots compliant. One option is to use compliant actuators, for example a McKibben muscle. This is a pneumatic artificial muscle with great resemblance to a biological muscle. A McKibben muscle consists of a 15 cm piece of bicycle tube, surrounded by a nylon braid of 20 cm. The endings of the tube and the braid are connected using a fitting. Inflating the muscle yields a decrease in muscle length and an increase in diameter and stiffness.

To perform research on the applicability of McKibben muscles as robotic actuators, a robotic arm is constructed at Philips Applied Technologies in Eindhoven. It has two degrees of freedom and is actuated by four McKibben muscles. The research goals are, firstly, to construct a predictive model of the robotic arm including McKibben muscles and, secondly, to construct controllers that guarantee accurate motion control of the robotic arm, using model knowledge on the robotic arm and the muscles. A predictive model of the McKibben muscle is proposed, which takes into account the change in muscle shape as well as in stiffness. This model is used in the total robotic arm model, also including the pneumatics and the rigid body dynamics of the arm. Dedicated experiments are performed to identify the parameters of the muscle model and the robotic arm model. Other experiments are used to validate whether the models give a correct prediction of the experimental robotic arm behavior. It appears that the robotic arm behavior is predicted correctly within a ...