Papers by Keyword: Kinematic Model

Abstract: Motion stability is the most important issue to be considered when designing a wheeled humanoid robot with bending torso, as it’s easy to capsize because of its high center of gravity. With ZMP (Zero Moment Point) method the motion stability of a wheeled humanoid robot with bending torso was analyzed. At first, the chain rule was used to model the kinematics of the wheeled humanoid robot, and then the process of calculating the ZMP of the robot was presented. With MATLAB the motion stability of the humanoid robot in three typical conditions is simulated and analyzed, and the simulation results were used to optimize some parameters of a wheeled humanoid robot we are designing.

Abstract: The paper presents the process of building and testing a geometric and kinematic model of a five-axis machining center, which can be used for accurate cutting processes simulation of complex parts. After building the model, it was be tested by simulating the machining process of a hip joint prosthetic device. The prosthetic device was chosen because of its complex shape and because it was obtained by a 3D scanning process, which means that the part was reconstructed using meshes, instead of surfaces, which makes the toolpath control more difficult.

Abstract: Serial industrial robots are able to perform point to point movements with a great degree of accuracy and flexibility. Thus, they are mostly used for welding, painting and pick-and-place task. Manufacturing processes require the control of movements on the entire path, so industrial robots are seldom used for this kind of task. The paper presents a research about using industrial robots for manufacturing prosthetic devices. The approach was to build a kinematic model of the robot and to implement it in a commercially available CAM program and to design and manufacture a milling unit as the end-effecter of the robot.

Abstract: The paper presents the structure of a precise parallel tri-axle manipulator with the functionality of progressing-tilting table. The end effector of the device is a platform, for which three coordinates of position are defined. The manipulator has three degrees of freedom: movement perpendicular to the base and rotation in two mutually perpendicular axes contained in the surface parallel to the base.The concept of the positioning mechanism is based on parallel tripod kinematics where the end effector – the platform – is seated on three active limbs – actuators. The use of parallel kinematics allowed modular construction of the positioning mechanism. The developed modular functional mechanism with minimal number of elements in kinematic chain ensures high positioning resolution. The concept of application of eccentric mechanism for platform positioning is an original idea in this solution. The compact construction allows applying the manipulator in medical devices that require meeting of the hygienic conditions in the medical test and research laboratories. The possibility of the utilisation of the precise manipulator covers wide areas of science and technology where precise positioning of the object is required, e.g. sample positioning for microscopes, scanning systems.

Abstract: This paper provided a new method of controlling the rehabilitative training system for the patients with upper limb movement disorder. On the basis of the computer through the patient's healthy limb motion gesture motion parameters, analyzed the kinematic model of human upper limb joints, obtained the kinematic parameters of upper body. Study the establishment of different categories of patients with upper limb virtual computer model system for the detection of relevant parameters. And according to the requirements of upper limb rehabilitation training for patients with upper limb rehabilitative training system, researched the dynamics model of human upper limb, and indicated a method which may provide scientific and effective training methods to recover function rehabilitation for patients.

Abstract: This paper aims to present different methods of volumetric verification in long range machine toll with lineal and rotary axes using a commercial laser tracker as measurement system. This method allows characterizing machine tool geometric errors depending on the kinematic of the machine and the work space available during the measurement time. The kinematic of the machine toll is affected by their geometric errors, which are different depending on the number and type of movement axes. The relationship between the various geometrical errors is different from relationship obtained in machine tool whit only lineal axes. Therefore, the identification strategy should be different. In the same way, the kinematic chain of the machine tool determines determines the position of the laser tracker and available space for data capture. This paper presents the kinematic model of several machine tools with different kinematic chains use to improve the machine tool accuracy of each one by volumetric verification. Likewise, the paper thus presents a study of: the adequacy of different nonlinear optimization strategies depending on the type of axis and the usable space available.

Abstract: Layer manufacturing machines are affected, the same way as traditional manufacturing processes, by systematic errors [.This lack of precision and poor dimensional accuracy can be reduced by software compensation techniques. This paper proposes a parametric error compensation technique based on pattern artifacts. This technique is verified on an Objet 350V 3D printer. To begin, these parametric techniques require the development of the machines kinematic model [. The data acquisition is performed with a CMM and a self-centering technique to measure conical sockets manufactured in the faces of pattern artifacts. After manufacturing various test patterns, with and without compensation, the achieved results are close to 80% reduction in mean error.

Abstract: Kinematic models, which contain flapping and deformations, of a bat flapping wing when it flies at medium speeds are presented in the study. The deformations include cambering - morphing in the chordwise direction, bending - morphing in the spanwise direction and twisting respecting angles of attack (AOA) varying along the length of the wing. In the study, we assumed a circular-arc-shaped deformation when cambering or bending occurs, and introduced controlling parameters for each morphing. Then we showed the expressions of the controlling parameters varying with time at the bat flight speed of 3m/s according to the data provided by a literature, and verified the reasonability of the assumptions at last.

Abstract: According to the special engineering requirement, a novel luffing mechanism with variable degree of freedom is presented in this study. The mechanism is assumed to be an ideal rigid body system and the degrees of freedom in different work conditions are calculated. Then the kinematic equations of mechanism are obtained by the geometrical and motional relationship of the components; meanwhile, the dynamic equations of mechanism are deduced by the Newton's mechanical law. The analytic model can be employed for the calculation and analysis of the mechanism features; furthermore, it can be used for the design of hydraulic and electric control system.

Abstract: This paper presents some considerations regarding the trajectory analysis for a class of mobile robots, namely two-wheeled differential drive mobile robots, one of the most utilized mechanical structures now in mobile robotics practice. The paper is continuing the computational analysis of the Cauchy problem associated to a mobile robot kinematics. The phaseportrait graphical tool of the mathematical soft MAPLE11, points out the influence of the initial conditions the initial velocities of the driving (left and right) wheels of the robot on the robot trajectory. Considering a pair of few simulation cases for the initial conditions brings a good reliability of the analysis. The issue of repetitive phenomena is very important to notice in this context, as in the analysis it is repeated a specific allure of the trajectory. It brings important features, both from mathematical and robotic analysis standpoint. The further changes are due to the initial conditions variations. Repetitive phenomena can be collected in order to realize a global panel of random distributed events in the kinematics of two wheeled differential drive mobile robot and to use the statistical observations in the further analysis.