Towards Simulation of Custom Industrial Robots

Abstract

The simulation tools used in industry require good knowledge of specific programming languages and modeling tools. Most of the industrial robots manufacturers have their own simulation applications and offline programming tools. Even if these applications are very complex and provide many features, they are manufacturer-specific and cannot be used for modeling or simulating custom industrial robots. In some cases the custom industrial robots can be designed using modeling software applications and then simulated using a programming language linked with the virtual model. This requires the use of specific programming languages, a good knowledge of the modeling software and experience in designing the mechanical part of the robot. Researches within the robots simulation field have been made by various research groups, especially in the field of mobile robots simulation. The results of their researches were complex simulation tools like: SimRobot (Laue et al., 2005) capable to simulate arbitrary defined robots in the 3D space together with the sensorial and the actuation systems; USARSim (Wang et al., 2003) or the Urban Search and Rescue Simulator using as main kernel the Unreal game which is very efficient and capable of solving rendering, animation and modelling problems; UCHILSIM (Zagal & del Solar, 2004) is a simulator which reproduces the dynamics AIBO robots and also simulates the interaction of these robots with objects in the working space; Rohrmeier’s industrial robot simulator (Rohrmeier, 2000) simulates serial robots using VRML in a web graphical interface. Our primary objective was to design and build a simulation system containing a custom industrial robot and an open architecture robot controller in the first part and a simulation software package using well known and open source programming languages in the last part. The custom industrial robot is a RPPR robot having cylindrical coordinates. In the first part of the project we designed and modeled the robotic structure and we obtained the forward kinematics, inverse kinematics and dynamic equations. From the mechanical point of view, the first joint contains a harmonic drive unit actuated by a DC motor. The two prismatic joints (vertical and horizontal) contain ball-screw mechanisms, both actuated by DC motors. The fourth joint is represented by a DC motor directly linked with the robot gripper. Another objective was to build a reprogrammable open architecture controller in order to be able to test different types of sensors and communication routines. The robot controller