FCA recently launched what it’s billing as the most advanced driving simulator in North America at its Automotive Research and Development Centre (ARDC) in Windsor, Ontario. The new Vehicle Dynamics Simulator (VDS) provides nine degrees of freedom and driver-specific calibrations to emulate a vehicle’s driving behavior on a wide range of surfaces and environments. The new hardware-in-the-loop test bench will permit iterating a host of simulated systems between concept and prototype phases to improve the overall product experience.
The new simulator is just part of ARDC’s growing role in FCA’s global system-level product development. The 23-acre, 215,000-ft2 facility adjacent to Windsor’s airport opened in 1996 and houses a wide spectrum of engineering talent and advanced tools, including teams dedicated to road-load chassis simulation, brake-system NVH, seating comfort and lighting. The simulator appears part an overall investment by FCA to leverage its engineering breadth to quantify and improve quality metrics.
Work began on the new simulator in November 2018 and it came online in early September 2019, with an overall investment of $10.1 Million (CAD) that included support from the SouthWest Ontario Development Fund. The simulator technology was developed by VI Grade, a leading supplier of system-level simulation founded in Germany in 2005, and since September 2018, part of the Spectris technology conglomerate based in the U.K.
Nine degrees of freedom
Many of the most advanced driving simulators make use of a “hexapod,” a driving-simulator platform supported by motion actuators to deliver six degrees (X, Y, Z, roll, pitch and yaw) of driving freedom; FCA’s new VDS uses nine actuators to provide three additional degrees of freedom to more-closely mimic vehicle dynamics. The entire setup is electrically actuated to minimize latency and provide the massive and instantaneous torque required to reproduce events up to 2g.
The VDS uses a hexapod supported on what it calls the “tripod,” and “floats” the 4.5-ton setup on a 20-ton, low-carbon, mild-steel baseplate. The entire tripod can be maneuvered (X, Y, yaw) with three additional actuators. The tripod floats on the polished and acutely level baseplate on only 3 microns of air, creating a near-frictionless interface similar to a puck on an air-hockey table. The pads that float the hexapod require only 120 psi of air pressure and powerful electromagnets maintain the miniscule clearance.
The simulator can be fitted with any vehicle body in the FCA lineup, from a Fiat 500 to a Ram HD pickup truck, and any number of surfaces or environments can be loaded into the simulator, supported by the adjacent control room. A curved, 180-degree screen in front of the pod fills the driver’s field of view and five 4K projectors (which took two days to align and calibrate) create the image on the screen. The projected image shifts in real-time using tracking data correlated to the position of the driver’s line of sight; frequent users of the VDS get a personal calibration to account for physiologic variables.
Another development tool
Initially, the VDS will be used to support chassis development, but in the future it also will be used in ADAS and HMI system development. Mohammed Malik (above), manager for the vehicle dynamics simulator, said it’s not so much about speeding overall vehicle development, but in identifying design changes much earlier in the development process. The VDS creates a hardware-in-the-loop test that permits subjective validation of simulated systems.
“We are using virtual models and putting those onto the simulator, and we can then do a subjective evaluation rather than on a virtual simulation where you're just doing objective evaluation,” Malik explained. “We can look at steering systems, brake systems, powertrain – all subsystems in a vehicle – and evaluate them subjectively prior to a prototype being built.”
“When you do your virtual simulations you're measuring all sorts of data. But until somebody actually drives it, you really don't get a feel for the vehicle, which happens later on when we get the prototypes,” Malik continued. “But with this virtual simulator, we are able to do that upfront while we're building those virtual models. So when the prototype comes along, we just have to do some minor tweaking.”
The VDS permits multiple subjective interactions before the physical prototype stage, Malik noted, which can be done rapidly in any conditions at any time of day. This makes physical prototyping more of a verification process than an initial validation of design, lowering project validation costs. Time gained back in the process will be used to improve quality, Malik said.
Driving the sim
FCA recently invited media to tour the facility and experience seat time in the new setup. The pod positions the cabin’s sill about six feet (2m) above the baseplate and a rolling stair platform is positioned to permit entry into the pod. The cluttered interior will feel familiar to any development engineer, with a host of tracking cameras added to correlate driver position, along with a five-point seat harness, an intercom system to communicate with the control room and associated switchgear to initiate or shut down the sim.
Media were permitted to sample the simulator outfitted with a Ram 1500 pickup cabin, piloting the truck around a simulation of the track at eastern Ontario’s Calabogie Motorsports Park. The surface of the Calabogie track was laser-scanned at a resolution of 5 mm2, but the system permits resolutions down to 1 mm2. With the simulator’s projected image keyed to the driver’s line of site, focusing on the vehicle’s intended path (versus looking around the cabin) is key to avoiding motion sickness. That directional focus most effectively correlates the projected visuals with the driver’s inputs and anticipated sensations.
The hexapod provides the driver with high-frequency inputs such as road-surface events (bumps, potholes, etc.), while the surface-plate motions provide lower-frequency events such as vehicle drifts. The combined effect, after a few moments of acclimatization, is of an unnervingly realistic experience. According to Malik, when calibrated to a professional driver, the fidelity easily permits subjective evaluation of vehicle subsystems by an experienced engineer. Most importantly, parameters of the models can be changed almost instantly from the control room.
“We're talking about the number of iterations we can do, the number of changes we can make. If I change this, what happens? Or if it's not tuned correctly, I don't need to buy physical components and make changes, I can make them on the fly,” Malik said. “When the driver says, ‘I need a little bit more stiffness on this shock,’ or, ‘I need to change the spring grades,’ I can make those changes while he's driving. He can provide feedback immediately, and whether that change has made a difference to vehicle performance.”Continue reading »