# A Conceptual Model for Joint Graphic Representation of
## 1 Introduction  
The development of a machine is a process that incorporates technical competencies from different fields of knowledge, which complement each other in order to obtain a design that is as suitable as possible to the requirements and objectives. This is the case of machines that combine mechanical and motion control technology. The mechanical information of a machine can be displayed by several kinds of technical drawings, while the motion of a servo axes machine is specified by text commands and time-based diagrams that are the reference to code the automation programs for the controllers. As analyzed in Section 2, current standards for machine mechanical designs do not cover the basic machine movements information requirements to also become the starting point for the machine automation development. There is no widespread systematic modeling methodology to represent machine preliminary designs including mechanical and motion control information, although a lot of relevant information in one technological view depends on information from the other. Furthermore, with the arrival of new controllers, servo-systems, and standards for motion control logic, new mechatronic software concepts are now common in the field of machines design and should also be taken into account by mechanical parts designers. For instance, if an electronic gear (a gear performed by the logic software) is going to be used instead of a mechanical one, that should be made explicit to mechanical designers early on in the design process. The lack of a common modeling space for automation and mechanical information can lead to a disconnection between the mechanical conceptualization of the system and that for automation, which can continue throughout the implementation process. The different nature of the information in both areas is an obstacle to define a single unified (mechanical and logical) representation. A problem appears when trying to combinetechnical drawings with text commands that describe the movements of the mechanical parts. These commands may consist of simple movements, but they may also be trajectories executed in a coordinated manner by several servo axes or even complex electronic virtual kinematic links, such as gears or e-cams combined with virtual servo axes. All of those have a crucial influence on the design and operation of the machine, but their presence and representation in the technical documentation is scarce. Another problem is that, despite there being common relevant information from both the mechanical point of view and from the motion control perspective, much of it is only of interest to one of the parties. For example, the distance that the mobile carriage of a linear actuator can travel is important for both points of view, but the metric of the screws that the machine is assembled with, or the types of data of the program variables, are only of interest to one of the parties. This paper presents a graphical representation system with both mechanical and motion control information--MMCS (mechanical and motion control schematics). It is a modeling framework halfway between mechanical and motion control fields and it deals with the problems mentioned above. It is intended to complement current standards rather than to replace them. The article is organized as follows. Main standards of graphic representation for mechanics and the programming languages to describe movements are analyzed in Section 2, paying special attention to the new electronic resources that are currently being used extensively in the development of mechatronic systems. This section continues with the study of non-standard, informal, or proprietary representation systems that are found in the scientific literature and documentation of industrial components manufacturers. In the Section 3, the conclusions on the state of the art are discussed.