Applied Mechanics and Materials Vols. 789-790

Abstract: Many pneumatic actuators have been developed in order to be lightweight with high output for decreasing impact force. So far, a pneumatic tendon-driven balloon actuator (balloon actuator) which is compact and lightweight has been developed for a robot hand and a rehabilitation device. However, for pneumatic actuator, it is difficult to maintain exact control because these actuators have constraints. For this study, we developed a stroke control system for a balloon actuator using a constrained model predictive control (MPC) scheme that can consider constraints of the plant output. As described in this paper, we compared and evaluated the control performance using MPC and PID.

Abstract: In this paper we will look at a jumping robot, whose controlled gliding is provided by the wings and tail, develop a mathematical model which describes the apparatus’ movement and pay special attention to the interaction of the wings and tail with the surrounding environment.

Abstract: In this paper, we describe the development and validation of the kinematic analysis of a low low-cost 4-link robot the first of its kind in Nigeria. This study comprises the following key tasks which describe the methodology for the robot development: design and kinematic analysis of the robot mechanism, construction/fabrication and assembly of the robot, system development (computer interface with the robot) and experimental validation of the robot control. The goal of this robot is to pick an object and drop the object in a specified position. The algorithm to control the robot on the computer was coded in Java and simulated in MATLAB/Simulink platform. The robot was experimentally verified and the results are presented in this paper. The experimental results show that robot development is feasible in Nigeria. The contribution of this study will enhance and promote robot control and development in Nigeria and developing third world countries.

Abstract: This article discusses the application of the Hirose ́s function for the achievement of the serpentine locomotion of the snake-like robot. Verification of the accuracy of locomotion was performed by simulation in the MATLAB 2012a program. At the beginning of the article, the biological aspects and the principle of the snake’s locomotion are mentioned. In the following chapter, the basic Hirose ́s function, which is subsequently transformed into the discreet shape in the Cartesian coordinates, is described. Moreover, relations for the calculation of rotation angle of the individual segments, wrapping angle and other similar parameters have been obtained. At the end of the article, simulations have been performed within which the influence of changes of the individual parameters of the function on the change of the shape of the snake-like robot have been observed.

Abstract: This paper proposed a new method to downgrade the kinematic mathematical model of parallel robots. A technique of complement mathematical models uses constraints to change the form of objective functions. An equivalent structure is used to replace the original structure of investigated robots. The difficulties encountered in solving problems having the transcendental form can be avoided by downgrading formula of the new mathematical model. The original formula which is usually in quaternary order can be downgraded to quadratic form. The main advantages of this method are understandable mathematical basis, high accuracy, and quick convergence. Carrying out solutions for pracitical kinematic problems of parallel robots becomes very promissable.

Abstract: In this paper, a low cost robotic wheelchair system with only a pan-tilt camera is explained. In order to reduce the development cost, an electric wheelchair using a visual marker which is capable of achieving a high level of precision in positioning an electric wheelchair without geometric features is proposed. Then, indoor navigation methods are explained, which enable automatic and hybrid navigation of an electric wheelchair with only a pan-tilt camera. Finally, experiment results obtained by considering a particular scenario for indoor navigation reveal the feasibility of the proposed robotic wheelchair system.

Abstract: In this paper, we propose a novel dual-loop control scheme (DLCS). We did not see such investigation of DLCS in the previous research work. DLCS scheme is a combination of classical PID and advanced state feedback control techniques. The proposed technique is used to control swing angle and trolley position of a 3DOF crane. Extensive simulations have been carried out using MATLAB / Simulink and practically validated on a Quanser 3DOF crane system. Experimental results indicate that the proposed DLCS control scheme improves crane operation by damping the payload oscillations. The scheme also smoothen the trolley motion. Our suggested technique provides better performance in terms of payload oscillations comparing to the classical PID.

Abstract: The design of lower limb rehabilitation robot can be categorized into two approaches: the end-effector and the exoskeleton. Both types of the robots have different advantages and disadvantages. The exoskeleton type is designed to mimic the kinematic structure of the human skeleton by controlling hip and knee joints but the end-effector type is driven at the footplate which allows patients to perform various gait training exercise. In this paper, the end-effector and exoskeleton device are compared based on dynamical analysis using Matlab's Simechanics simulation. The hybrid lower limb rehabilitation robot is also proposed based on the exoskeleton robot with the adjustable mechanical coupling interface between human and robot and the active footplate. The hybrid design combines the advantages of both the exoskeleton and the end-effector by allowing the mechanical coupling parameters and the active footplate controller to be adjustable at different stages of training. The proposed design can improve both joints misalignment and joint trajectory tracking problems in both existing approaches.

Abstract: In precision robotic applications, inaccuracy in workpiece geometry has been a common problem to the precise processing of the workpiece. Due to manufacturing defects and workpiece deformation, the actual geometry of the workpiece deviates from its nominal 3D CAD model which is defined as model error. For many of the existing industrial robotic applications today, the robot path for processing the workpiece is planned based on the nominal 3D CAD model of the workpiece. Hence, the model error of the workpiece leads to error in the robot path planning eventually inducing inaccurate processing. To enhance the accuracy of the robot in processing the workpiece, a framework for in-situ model error compensation has been proposed. Prior to the processing of each workpiece, the proposed technique employs 3D optical laser scanning technology to capture the actual 3D model of the workpiece and compares it with the nominal model to establish the model errors. The nominal path of the robot initially created based on the nominal CAD model is then modified according to the model error. Thus, this step performs the in-situ model error compensation making the robotic task adaptive to the actual workpiece geometry. Experiments have been conducted to verify the proposed framework and an accuracy of up to 30 micrometers has been achieved in model error identification and compensation. The proposed technique can be employed in applications such as high precision robotic tasks, where accuracy of task execution is an important factor.

Abstract: A hardware-in-the-loop (HIL) platform for unmanned air vehicle (UAV) systems is designed that demonstrates flight attitudes on yaw, pitch and roll axes. The design combines a sophisticated flight simulation software with a platform capable of moving 360 degrees on all axes. This enables the testing of the flight sensors and autopilot algorithms for all sorts of scenarios including emergency and acrobatic cases where an indefinite number of full rotations in the yaw, roll and pitch might take place.