A new suspension system simulator not only helps NASCAR racing teams improve their performance but also promises to aid chassis development for OEM cars.
Designed by engineers at Livingston & Haven, a Charlotte-based distributor and integrator, the system allows technicians to acquire motion profiles and tune suspensions right on the simulator.
During testing technicians drive the car onto the rig, so that the wheels rest on top of four legs that are capped by scale pads. The rig then lifts the car, with all four legs moving synchronously to its “home position,” about 7 inches off the road level. Tie downs, connected to the frame of the rig and the chassis, hold the car rigid for testing. Operators can then actuate each corner of the rig independently – or synchronously -- to measure both position and force control. Users can also add shock potentiometers for even more data.
Engineers have developed two versions of the system, the first based on hydraulics and the most recent on a ball-screw, servo-motor design, explains Craig Hill, an engineering manager with L&H. The hydraulics version, called the K-RIG, features MTS Temposonics sensors mounted in cylinders housed within the four legs. The sensors interface with a proportional valve and a force-and-position digital controller to achieve precise position measurement. For data acquisition, the K-RIG uses an industrial PC and VLC control software from Phoenix Contact, as well as HMI software from InduSoft.
When technicians perform motion profiles on each of the legs, they can plot the force-over-position curve of an individual wheel suspension package. These profiles identify interference fits, perform spring cataloging and coordinate all data against shock travel and wheel travel. For NASCAR teams, this information translates to a faster tuning cycle and better performance, resulting in more wins for the teams using the machine.
“The key to this machine is that this information is acquired on the car, not on the track,” says Hill. “The K-RIG acquires more data than on-site track testing without the expense.”
In fact, the racing teams using the K-RIG saw a dramatic jump in their cars’ positions during the 2006 season, as compared to the 2005 season, according to Hill.
In late January, L&H formed a new company, called Accelerating Developments International (ADI), to sell and service the rigs. Customers, including race car teams and companies that supply chassis systems to automakers, can either lease time on the rigs or buy them outright at a cost of $275,000 to $300,000.
The ADIteam has designed a new version of the simulator called the KD-RIG (“K” for kinematics and “D” for dynamics). The design, featuring a ball screw and an Indramat servo motor within each leg of the rig, delivers much faster operation, says Hill. For example, the actuators can raise a tire up and down at a velocity of 5 inches per second during testing, versus just 1 inch per second in the hydraulic version. The new rig features an IOtech data acquisition system. As for engineering tools, the ADI team used 3D modeling software for the design of the KD-RIG and Collaboration Suites for project management.
“The hydraulic rig was very successful, but now we’ve redesigned it completely for even better performance,” says Hill. “This gives us a more dynamic rig that not only yields greater accuracy but is also infinitely adjustable.’’
For more information, e-mail Craig Hill at rch@lhtech.com.
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