Research and engineering firm cuts development time by 33 percent with LMS Virtual.Lab Motion
ETA uses Siemens PLM Software solution to help reduce time-torace from 9 months to 5 months
Facing an uphill battle
Hill-climb racing is a branch of motorsports in which drivers compete against the clock on an uphill road. Incorporated in 1987, ETA s.r.l. (ETA) is a research and engineering company that works with firms from the automotive, energy and mechanical industries. One of the most interesting projects ETA has in its collaboration portfolio is PICCHIO, an Italian racecar and road car producer that often wins hill-climbing races.
The first hill-climb race took place in Colorado in 1916 under the name of “Pikes Peak International Hill Climb competition.” In this competition, the vehicles race on a properly secured, 20 kilometer (km) common public road section, starting from an altitude of 2,900 meters and climbing to 3,300 meters.
This is the kind of engineering challenge that ETA faces when it develops hillclimbing racing cars for PICCHIO.
When a race vehicle curves on a classic plane curve, as in a Formula 1 circuit, there is a high load on the external front tire and a low load on the internal front tire while the rear axle remains balanced. Due to the high slope and road banking during an uphill turn, the vehicle’s balance and load drastically shifts. As a result, the internal wheel will frequently have a very low vertical load and sometimes does not touch the road at all. This creates many issues for the driver, such as undesired vibration effects, excessive increase in the pitch of the car’s front suspension and loss of grip during acceleration.
Winning the virtual race
The need for technical solutions in response to the control requirements for such racecars has prompted the implementation of a contractive scheme. This configuration for the front suspension is called “opposite springs.”
ETA decided to employ LMS Virtual.Lab™ Motion software from Siemens PLM Software, a 3D multi-body simulation tool, to get a better understanding of the hill-climb acceleration dynamics and to simulate the vehicle model in two steps:
- Create a physical model of the front suspension on the vertical direction to better understand the mechanism
- Create a detailed multi-body model by using telemetry as the vehicle runs on a cornering section of the road
Engineers at ETA used computer-aided design (CAD) inputs to make a complete model of the vehicle and to create a helical track – obtained by global positioning system (GPS) data and measurements – on which the vehicle virtually raced using LMS Virtual.Lab Motion. The idea was to observe how the vehicle reacted to critical uphill curved track stretches and to conduct crucial dynamic analysis of the damping and suspension system.
The simulation confirmed that there was a general loss of traction and a difference between the heights of the front axle extremes. This meant that one of the two tires had less contact with the ground, hurting the vehicle’s overall performances.
ETA found the solution for the problem by integrating the contractive device, consisting of an additional spring in the damper system, to push the internal tire down to the ground. The device was also designed to achieve easy suspension setups during racing, such as preload adjustability of the main and extension springs, replacement of the springs, bulk space and lightness.
The design process involved not only parametric variations between contractive and normal suspension, but also model variations. For instance, the non-contractive solution implemented a stroke end device with a very high stiffness value that allowed the evaluation and selection of the most promising solutions, and minimized the experimental activity.
The tests were carried out on the track with competition testing. The results confirmed significant performance improvements over the previous setup configuration.
Reducing development time
The decision to go with LMS™ software was not taken lightly. During benchmarking, the pros and cons of leading simulation software were weighed. Ultimately, LMS Virtual.Lab™ software was chosen over other solutions because it allowed the import of the pre-existing full CAD vehicle multi-body model and had a wide application scope and versatility.
“While simulation with competitors’ software would have required us to rebuild the racecar model from scratch, the use of LMS Virtual.Lab allowed us to simply import the entire model in the software frame, sparing us from painful, time-consuming individual data import,” says Pierluigi Antonini, an engineer from the Test & Simulation division of ETA.
ETA remains very happy with the choice it made. Before the firm chose LMS Virtual.Lab, the development route at ETA represented a one-way process. Once a design was approved by the development division and reproduced by simulation, it was impossible to make any modifications to the model.
“We had to start the simulation again from scratch to modify any aspect of the system’s design,” says Antonini. “This created subsequent project delays. But thanks to LMS Virtual.Lab, the process at ETA is now a circular one; the virtual model can always be modified by the Test & Simulation division if requested.”
He notes, “We strongly appreciate how LMS Virtual.Lab Motion cuts down our development time by 33 percent and allows us to increase the number of models. Back in 2004, it took ETA and PICCHIO nine months to get a new vehicle model on the race track. In 2010, PICCHIO and ETA were able to create a new racecar in five months, and PICCHIO won their first race only two months later thanks to LMS Virtual.Lab.”