The skid pad at Bosch's Flat Rock, MI, proving grounds doubled in size to 937,000 ft² (87,000 m²) as part of a recent $8 million upgrade. Originally built for antilock brake system (ABS) testing, a more expansive testing zone was required to meet the MY2012 FMVSS126 mandate that light passenger vehicles weighing up to 10,000 lb (4.5 t) be equipped with electronic stability control (ESC) technology.
Bosch's new asphalt vehicle dynamics area provides a run-up for high dynamic maneuvers, including fishhook and large radii J-turns, as well as ample space for conducting trailer sway mitigation tests. To support development of lane keeping and lane departure detection as well as other video and radar-based technologies, specific surfaces at the proving grounds are adorned with various lane and other markings. From an eco-perspective, a blend of clay, sand, and milled asphalt from the original pavement was used to construct "green" gravel shoulders.
An all-new feature of the proving ground is a three-lane bank curve that allows Bosch engineers to test vehicle system robustness. "Since the ESC system relies on sensor inputs for the model calculations, this bank curve increases our ability to make sure that the models are calculating properly, thus preventing false activations. And since we are better equipped to maintain high vehicle speed through the curve, that allows us to test certain requirements that require high-speed dynamic maneuvers," explained Maajed Huq, Director of Engineering, Chassis Control North America for Robert Bosch LLC.
Prior to the in-depth renovations, the proving grounds did not have a dedicated hydroplane surface. "Bosch engineers previously improvised by flooding an area of the old vehicle dynamics area with water and used fire hoses for water containment," said Huq, admitting "this was not an ideal simulation as water depth could not be accurately controlled." With a dedicated hydroplane area, water depth is now a controllable testing parameter.
In addition to Bosch engineers, users of the Flat Rock proving grounds have included OEMs and driveline component suppliers. Bosch has seven proving grounds outside the U.S. and two other stateside proving grounds (in New Carlisle, IN, for foundation/actuation brake system testing and development as well as a winter test facility in Baudette, MN). "Bosch's chassis control division has also utilized OEM proving grounds to perform OEM-specific testing on surfaces available at those facilities. These activities will not be impacted by the renovation/expansion project at Flat Rock," noted Kay Stepper, Director of Marketing and Product Planning, Chassis Control North America for Robert Bosch LLC.
The Flat Rock track loop was extended from 0.75 to 1.4 mi (1.2 to 2.3 km) to provide additional space for acceleration needs. "This allowance is very critical for testing functions such as trailer sway mitigation on large pickup trucks loaded to gross vehicle weight. It is also very important to have a larger run-up/run-off area from a safety perspective," said Huq. Since its original 1989 design, the Flat Rock facility has been a key tool in Bosch's development of crash avoidance technologies.