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In this paper, dynamics and control of a Tendon-based continuum robot is investigated. The curvature is assumed that constant in each section of continuum robot. Kinematic equation is established on the basis of the Euler-Bernoulli beam. The dynamic model of the continuum robot is derived by using Lagrange method. In this paper, robot control is performed in two parts: firstly, Dynamic model is assumed to be known and position and velocity tracking control has been by using the feedback linearization method, But uncertainties in the dynamic model, are constantly challenged the control of continuum robots. For unknown parametric quantities such as mass coefficients, one way is simply substitutes a fixed estimate for the unknown parametric quantities. In this case tracking error is not equal to zero but it’s bounded. For many applications, we cannot assume that tracking error vector is not equal to zero. In such cases we use adaptive controller. In this paper the total mass of the primary backbone and secondary backbone are uncertain parameters, therefore, a new adaptive controller is presented to estimate those uncertainties while cause to asymptotically stable for tracking error. Simulation results show good performance in velocity and position tracking.

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Under a constant loading condition, use of a controller with constant coefficients can be acceptable for servo pneumatic systems. However in variable loads with widespread changes, more advanced control methods should be considered to achieve desirable performance. In this paper, an adaptive controller is designed and implemented to a variably loaded servo pneumatic system with PWM driven switching valve. In the under examination servo pneumatic system, PWM driven fast switching valve is used instead of expensive servo or proportional valves. Real time identification of system parameters is performed using input-output data and controller parameters are adjusted instantaneously. “Self-tuning regulators” algorithm, in which controller parameters obtain from solving a design problem, is applied to design the proposed adaptive controller. The designed controller is applied to the servo pneumatic system via an interface board and its performance is compared with PD and multi model controller. Unlike the proposed method in multi model control method, a number of constant loads should be considered and corresponding to each load a fixed controller is designed. Experimental results demonstrate the high performance of the adaptive controller under variable loads.

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Developed novel adaptive controller is suitable for time-varying linear system subject to harmonic reference signal with variable average and amplitude. This controller is experienced successfully at high frequencies on voice coil actuator (VCA) fatigue testing machine which has variable time-varying dynamic. In this applicable approach, assuming having linear system around operation point and slow rate time-variation, tracking control of harmonic reference signal is replaced with regulation control of average and amplitude of harmonic reference signal. In the proposed method, a Single-Input Single-Output (SISO) system estimated by a fourth-order model, is considered as the simplest decoupled Multi-Input Multi-Output (MIMO). This causes reduction in the amount of computations and no need to complicated hardware. Consequently, the proposed method provides a real-time control for implementation of random harmonic loading with rapid changes in average and amplitude. To complete control objectives, primary control by the PI controller, dynamic saturation blocks and linearization blocks, are employed. Soft start of loading due to PI controller, provides enough time for system identification of adaptive controller and guarantee avoidance of impact on specimen and credibility of fatigue test. In addition, the using of linearization blocks for trajectory planning of command signal and using of dynamic saturation blocks, restrain the overshoot of loading and prevent excitation of unmodelled dynamics. Finally, different materials under different frequency loading are successfully tested.