Man-in-the-control-loop simulation of manipulators

A method to achieve man-in-the-control-loop simulation is presented. Emerging real-time dynamics simulation suggests a potential for creating an interactive design workstation with a human operator in the control loop. The recursive formulation for multibody dynamics simulation is studied to determine requirements for man-in-the-control-loop simulation. High speed computer graphics techniques provides realistic visual cues for the simulator. Backhoe and robot arm simulations are implemented to demonstrate the capability of man-in-the-control-loop simulation

Interactive Physically-Based Simulation of Roadheader Robot

Roadheader is an engineering robot widely used in underground engineering and mining industry. Interactive dynamics simulation of roadheader is a fundamental problem in unmanned excavation and virtual reality training. However, current research is only based on traditional animation techniques or commercial game engines. There are few studies that apply real-time physical simulation of computer graphics to the field of roadheader robot. This paper aims to present an interactive physically-based simulation system of roadheader robot. To this end, an improved multibody simulation method based on generalized coordinates is proposed. First, our simulation method describes robot dynamics based on generalized coordinates. Compared to state-of-the-art methods, our method is more stable and accurate. Numerical simulation results showed that our method has significantly less error than the game engine in the same number of iterations. Second, we adopt the symplectic Euler integrator instead of the conventional fourth-order Runge-Kutta (RK4) method for dynamics iteration. Compared with other integrators, our method is more stable in energy drift during long-term simulation. The test results showed that our system achieved real-time interaction performance of 60 frames per second (fps). Furthermore, we propose a model format for geometric and robotics modeling of roadheaders to implement the system. Our interactive simulation system of roadheader meets the requirements of interactivity, accuracy and stability

Development of a Hybrid Simulator for Underwater Vehicles with Manipulators

This article describes a hybrid simulation approach meant to facilitate the realization of a simulator for underwater vehicles with one or more manipulators capable of simulating the interaction of the vehicle with objects and structures of the environment. The hybrid simulation approach is first described and motivated analytically, then an analysis of simulation accuracy is proposed, where, in particular, the implications of added mass simulation are discussed. Then, a possible implementation of the proposed architecture is shown, where a robotic simulator of articulated bodies, capable of stable and accurate simulation of contact forces, although unfit to simulate any serious hydrodynamic model, is tightly interfaced with a general purpose dynamic systems simulator that is used to simulate the hydrodynamic forces, the vehicle guidance, navigation, and control system, and also a man-machine interface. Software details and the technicalities needed to interface the two simulators are also briefly presented. Finally, the results of the simulation of three operational scenarios are proposed as qualitative assessment of the simulator capabilities

Aeronautical Engineering. A continuing bibliography with indexes, supplement 156

This bibliography lists 288 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1982

Modelling, Simulation and Control of the Walking of Biped Robotic Devices—Part I : Modelling and Simulation Using Autolev

A biped robot is a mechanical multichain system. The peculiar features, that distinguishes this kind of robot with respect to others, e.g., industrial robots, is its switching nature between different phases, each one is the same mechanics subject to a different constraint. Moreover, because these (unilateral) constraints, represented by the contact between the foot/feet and the ground, play a fundamental role for maintaining the postural equilibrium during the gait, forces and torques returned must be continuously monitored, as they pose stringent conditions to the trajectories that the joints of the robot can safely follow. The advantages of using the Kane’s method to approach the dynamical model (models) of the system are outlined. This paper, divided in three parts, deals with a generical biped device, which can be an exoskeleton for rehabilitation or an indipendent robot. Part I is devoted to modelling and simulation, part II approaches the control of walk in a rectilinear trajectory, part III extends the results on turning while walking. In particular, this part I describes the model of the biped robot and the practicalities of building a computer simulator, leveraging on the facilities offered by the symbolic computational environment Autolev that complements the Kane’s method