The concept of utilizing the Coandia effect to produce stable flight in saucer type Aerial Vehicles (AV) was first conceived in 1935 by Henri Marie Coanda. Coanda's proposed AV design remained a relatively unexplored curiosity for decades until the recent surge in popularity of small Unmanned Aerial Vehicles (UAV) revitalized interest in the topic. Coandä effect UAV offer some distinct advantages over standard multirotors due to their robust frame design, which offers a unique mix of crash resistance, flight safety, and flight performance making them ideal for Human-Robot Interaction (HRI) applications. While much work has been performed in the area of characterization for Coanda surfaces and improved mechanical design of saucer type UAV, little work has been found in the literature discussing stability and attitude control of the platform. This work seeks to contribute to the study of these drones by introducing an approximate servo mapping for desired control effort of a particular prototype, and an experimental control law implemented within the framework of a modified commercially available flight stack.

This paper proposes a new adaptive repetitive visual-servo control system for a moving high-flying vehicle (HFV) with an uncalibrated camera to monitor, track, and precisely control the movements of a low-flying vehicle (LFV) or mobile ground robot. When deployed, a remote operator of the HFV defines the desired trajectory for the LFV in the HFV's camera frame (image frame). Due to the circulatory motion of the HFV, the resulting motion trajectory of the LFV in the image frame is periodic in time, thus an adaptive repetitive control system is exploited to improve the tracking precision from one operating period to the next. Not only is the adaptive control law able to deal with uncertainties in the camera's intrinsic and extrinsic parameters, but it can also tolerate uncertainties in the localization of the LFV. The design and stability analysis of the closed-loop control system is presented, where the Lyapunov approach is used to show stability. Simulations and experimental results are presented to demonstrate the effectiveness of the method for controlling the movement of a low-flying quadcopter vehicle. Results show good tracking performance for three simulated test cases, where the average maximum tracking error is reduced by approximately 75% compared to the performance of a standard adaptive visual-servo controller.

In this paper, we introduce the open-loop motion planning and control strategy for an underwater vehicle actuated by a soft artificial muscle actuator. The artificial muscle used for this underwater application is an ionic polymer metal composite (IPMC) which can generate bending motion in aquatic environments. In this research, the double ring structured nonlinear neural oscillator is proposed for generating undulatory motions in the water. The overall dynamic model of the flexible IPMC actuator including its fluid interaction terms is used for the motion planning and open-loop controller design. The IPMC used in this study is a patterned or segmented type where the electrode surface of the actuator is encoded such that each segment can be controlled independently for effectively generating an undulatory motion. Computer simulations show that the proposed neural oscillator based controller can be effectively used for the underwater locomotion applications, and can be extended to the closed-loop controller where the precise maneuver is needed in the unstructured aquatic environments. Experimental results are also presented to validate the proposed scheme.

In this paper, we introduce an analytical modeling approach for dynamic shape characterization of the ionic polymer metal composite (IPMC) actuator under the input voltages based on the RC electrical model and mechanical beam model. The proposed method can be used for modeling the general IPMC bending actuator in a single segment or multiple segments or patterned form. The segmented design offers more flexibility in controlling the shape of the actuator when compared with the single-segment design as it can be used to generate undulatory wave form instead of a simple oscillation form. Considering the inherent nature of large deformation in the IPMC actuator, a large deflection beam model is developed and augmented with the electrical RC model to present a state space model of the actuator system. Experimental results are compared with the computer simulated IPMC actuator model to validate the proposed model

The paper presents for analysis and control of smart fins for a subsonic projectile. The fin should be able to produce maneuvering force and moment that can control the rotation angle of a projectile fin during flight. The objective of this paper is to present a fuzzy logic controller for a smart fin that is activated by piezoelectric actuator. The beam-based piezoelectric actuator is enclosed within the hollow fin. It has an end fixed to the rotation axle of the fin while the other end is pinned at the tip of the fin. A dynamic model of the system, including external moment due to aerodynamic effects, is obtained using the finite element approach. A general design for a fuzzy logic controller for the fin is presented. The membership functions of the fuzzy variables for this controller are determined using a hybrid genetic algorithm. Simulation results show that the proposed controller works satisfactorily under various operating conditions

In this investigation, ionic polymer metal composites (IPMC) are considered for use as a means of aquatic propulsion. A simple propulsor is constructed to show capabilities of using an IPMC actuator. The thrust produced by the propulsor was recorded and reported showing suitable thrust for small applications. IPMC were then compared with competing electro-active polymers in a theoretical propulsor study showing that IPMC are quite competitive with similar actuator materials. An equivalent circuit to model the force behavior of an IPMC can be used to explain force behavior for various geometric configurations of IPMC leading the way for design and use of IPMC aquatic propulsors.

In this paper the control of a flexible joint manipulator is designed using an adaptive output-feedback controller based on the backstepping design. The parameters of system are assumed to be unknown and only the motor position and link position measurements are used for the synthesis of the controller. A canonical state representation of the system is derived and filters are designed to obtain estimates of the derivatives of motor angle and link angle. Then an adaptive control law for the trajectory control of link displacement angle is derived. Compared to the same adaptive controller which only measures the link displacement angle, the order of the proposed controller is halved (order of 2) and the complexity of the control law can be reduced dramatically. Also, the proposed controller does not require the bounds on uncertain parameters for the control law derivation as compared to other output adaptive control laws.

The paper presents an approach to end point control of elastic manipulators based on the nonlinear predictive control theory. For the derivation of the predictive control law, a vector function s is chosen as a linear combination of the trading error,its higher order derivatives, and the integral of the trading error for robustness. A control law is derived by minimizing a quadratic function of the predicted value of s and control torques. This approach avoids the instability of the zero dynamics encountered in the controller design using feedback linearization and variable structure control techniques for end-point control. Simulation results are presented for a one link flexible manipulator to show that in the closed-loop system accurate end point trajectory control and vibration damping can be accomplished in the presence of uncertainty in the system parameters.

We treat the question of position and force control of three-axis elastic robotic systems on a constraint surface in the presence of robot parameter and environmental constraint geometry uncertainties. A sliding mode control law is derived for the position and force trajectory control of manipulator. Instability of the zero dynamics is avoided by controlling a point which lies in the neighborhood of the actual end point position. The maneuver of the arm using the sliding mode controller causes elastic mode excitation. For point-to-point control on the constraint surface, a stabilizer is designed for the final capture of the terminal state and vibration suppression.>

The integration of automated measurement and continuous-path robot control plays an important role in autonomous manufacturing systems. A technique is presented that provides simultaneous measurement of the position and orientation of a 3D object surface point, using a cross-shaped light beam. This is an important step towards upgrading a robot manipulator to a unit with a high degree of flexibility with rapid, convenient automatic contour programming. The methodology presented covers the measuring of the position and orientation of a surface point, and the generation of a bicubic surface patch using the measured data.>