Kinematics Support for Design and Simulation of Mechatronic Systems Rajarishi Sinha 1 , Christiaan J.J. Paredis 1,2 and Pradeep K. Khosla 1,2 1 Institute for Complex Engineered Systems, Carnegie Mellon University, Pittsburgh, PA 15213, USA 2 Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA Key words: CAD, Port-based modeling, VHDL-AMS, Simulation, Mechatronics, Multi-body mechanics, Design consistency Abstract: We present a framework that verifies and maintains the consistency between the representations of the form, function and behavior of mechatronic devices. These three aspects of the device represent the geometry, the task, and the actions taken to realize the task, respectively (Pahl and Beitz, 1996). They evolve simultaneously through the design process. When the designer makes a change to one aspect of the representation, our framework automatically updates all other aspects impacted by this change and reports inconsistencies. Inconsistencies occur when the kinematic behavior of the device does not match the form, or the kinematic behavior does not match the currently specified functional description. Continuous feedback of this nature shortens the design-simulate cycle for product design. To represent the components in the device we use a port-based modeling paradigm. Components encapsulate both form and behavior and are interconnected to form the system model of the device. Simulation models for the components are defined in VHDL-AMS and are solved with a commercial solver. 1. INTRODUCTION AND MOTIVATION The realization of new mechatronic devices is characterized by ever shortening times to market, along with increasing customer demand for improved quality. In this business environment, it is important for the designer to be able to simulate the behavior of the current state of the design. As the design evolves, its form, behavior and intended function should be consistent with each other (Figure 1). In addition, information about the behavior should be automatically obtained from the CAD model of the device. Simulation of the behavior will catch inconsistencies early in the design process, reducing the need for physical prototyping and decreasing the time to market. To accomplish this goal, we are developing a software environment for simulation-based design, in which modeling and design tools are tightly integrated. Consider the following scenario. A designer begins the design process by defining the desired kinematic function of a device. She then converts the desired function into an intended behavior described by a simple ball-and-stick model. As the design evolves, she introduces information about local geometry at the joint contact, then the complete geometry, and finally the inertial properties. At each stage, the representation is enriched and a simulation can be generated with the available information. On demand, the