Multibody Systems Approach to Vehicle Dynamics P2

The origin of MSC.ADAMS can be traced back to a program of research initiated by Chace at the University of Michigan in 1967. By 1969 Chace (1969, 1970) and Korybalski (Chace and Korybalski, 1970) had completed the original version of DAMN (Dynamic Analysis of Mechanical Networks). This was historically the first general program to solve time histories for systems undergoing large displacement dynamic motion. This work led in 1971 to a new program DRAM (Dynamic Response of Articulated Machinery) that was further enhanced by Angel (Chace and Angel, 1977). The first program forming the basis of MSC.ADAMS was completed by...
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Multibody Systems Approach to Vehicle Dynamics P218 Multibody Systems Approach to Vehicle Dynamics The origin of MSC.ADAMS can be traced back to a program of research initiated by Chace at the University of Michigan in 1967. By 1969 Chace (1969, 1970) and Korybalski (Chace and Korybalski, 1970) had completed the original version of DAMN (Dynamic Analysis of Mechanical Networks). This was historically the first general program to solve time histories for systems undergoing large displacement dynamic motion. This work led in 1971 to a new program DRAM (Dynamic Response of Articulated Machinery) that was further enhanced by Angel (Chace and Angel, 1977). The first program forming the basis of MSC.ADAMS was completed by Orlandea in 1973 and published in a series of two ASME papers (Orlandea et al., 1976a, b). This was a development of the earlier two-dimensional programs to a three-dimensional code but without some of the impact capability contained in DRAM at that time. Blundell (1991) describes how the MSC.ADAMS software is used to study the behaviour of systems consisting of rigid or flexible parts connected by joints and undergoing large displacement motion and in particular the application of the software in vehicle dynamics. The paper also lists a num- ber of other systems based on MSC.ADAMS that had at that time been developed specifically for automotive vehicle modelling applications. Several of the larger vehicle manufacturers have at some time integrated MSC.ADAMS into their own in-house vehicle design systems. Early examples of these were the AMIGO system at Audi (Hudi, 1988), and MOGESSA at Volkswagen (Terlinden et al., 1987). The WOODS system based on user defined worksheets was another system at that time in this case developed by German consultants for Ford in the UK (Kaminski, 1990). Ford’s global vehicle modelling activities have since focused on in-house generated linear models and the ADAMS/Chassis™ (formerly known as ADAMS/Pre™) package, a layer over the top of the standard MSC.ADAMS pre- and post-processor that is strongly tailored towards productivity and consistency in vehicle analysis. Another customized application developed by the automotive industry is described in Scapaticci et al. (1992). In this paper the authors describe how MSC.ADAMS has been integrated into a system known as SARAH (Suspension Analyses Reduced ADAMS Handling). This in-house system for the automotive industry was developed by the Fiat Research Centre Handling Group and used a suspension modelling technique that ignored suspension layout but focused on the final effects of wheel centre trajectory and orientation. At Leeds University a vehicle-specific system was developed under the supervision of Crolla. In this case all the commonly required vehicle dynamics studies have been embodied in their own set of programs (Crolla et al., 1994) known as VDAS (Vehicle Dynamics Analysis Software). Examples of the applications incorporated in this system included ride/handling, suspensions, natural frequencies, mode shapes, frequency response and steady state handling diagrams. The system included a range of models and further new models could be added using a pre-processor. Crolla et al. (1994) also define two fundamental types of MBS program, the first of which is that such as MSC.ADAMS where the equations are Introduction 19generated in numerical format and are solved directly using numerical inte-gration routines embedded in the package. The second and more recenttype of MBS program identified formulates the equations in symbolic formand often uses an independent solver. The authors also describe toolkits ascollections of routines that generate models, formulate and solve equa-tions, and present results. The VDAS system is identified as falling intothis category of computer software used for vehicle dynamics.Other examples of more recently developed codes formulate the equationsalgebraically and use a symbolic approach. Examples of these programsinclude MESA VERDE (Wittenburg and Wolz, 1985), AUTOSIM (Sayers,1990), and RASNA Applied Motion Software (Austin and Hollars, 1992).Crolla (Crolla et al., 1992) provides a summary comparison of the differ-ences between numeric and symbolic code. As stated MBS programs willusually automatically formulate and solve the equations of motion althoughin some cases such as with the work described by Costa (1991) and Holt(Holt and Cornish, 1992; Holt, 1994) a program SDFAST has been used toformulate the equations of motion in symbolic form and another programACSL (Automatic Continuous Simulation Language) has been used togenerate a solution.Special-purpose programs are designed and developed with the objectiveof solving only a specific set of problems. As such they are aimed at aspecific group of problems. A typical example of this type of programwould be AUTOSIM described by Sayers (1990, 1992), Sharp (1997) andMousseau et al. (1992) which is intended for vehicle handling and has beendeveloped as a symbolic code in order to produce very fast simulations.Programs such as this can be considered to be special purpose as they arespecifically developed for a given type of simulation but do, however,allow flexibility as to the choice and complexity of the model. An exten-sion of this is where the equations of motion for a fixed vehicle modellingapproach are pr ...