Integrated camera system captures component and vehicle body displacements directly during kinematics and compliance testing
System enables the relationships between applied forces and deflections to be studied with unprecedented accuracy
Increases the ease with which competitor vehicles can be analysed and prototype vehicles can be validated
Bradford-on-Avon, UK, 17th April 2018… AB Dynamics, one of the leading suppliers of advanced automotive test systems, has introduced a major upgrade to its widely respected SPMM 5000 Kinematics and Compliance (K&C) testing machines. Called K&C Inspect, the new development allows users to capture the movement of up to 50 target points in three dimensions which is then automatically synchronised and recorded with the traditional data collected during K&C testing. It is a significant step forward that further enables the analysis of a competitor’s vehicle or validating the characteristics of a pre-production prototype using an SPMM.
“This is a major breakthrough for K&C testing because it enables our customers to measure the movement of elements of the vehicle that are often unaccounted for in traditional testing,” explained Matthew Dustan, Senior Project Engineer, SPMM. “In the past, measurement was more or less limited to wheel position movements and tyre contact wheel forces. Body movement was measured by draw wire encoder or inferred from the position of the centre table to which the body is clamped. In reality, all vehicles are flexible so by capturing the positions of key points, our clients can derive substantially more information from K&C testing.”
The system uses a pair of AICON HF4 photometric cameras on an adjustable mounting system with a data capture rate of up to 1000Hz. A powerful combination of SPMM and AICON software locates and tracks the X, Y and Z position of the user-selected targets, automatically transforming the data into K&C rig coordinates. The displacement data is stored alongside other K&C results in the SPMM database, ready for export and processing, and can be graphed against other test data channels in AB Dynamics’ graphing and analysis programs, including Grapher.
Previous attempts to incorporate accurate deflection measurement into K&C testing using stand-alone 3D measurement systems have left engineers struggling to reliably orient the camera coordinate system to their other data thereby failing to get the results in a useable form. K&C Inspect can do this seamlessly, thanks to extensive work by AB Dynamics to effectively integrate the AICON software with the existing SPMM software.
One of the particular challenges overcome by AB Dynamics in developing the new system was ensuring that the cameras reliably tracked the individual targets at all times. A sophisticated series of logical steps within the software enables the system to identify and track each of the targets and quickly diagnose error conditions, such as a target becoming obscured during suspension movement.
As SPMM users continually look for greater value from K&C testing, adding the capability to accurately measure other deflections is a natural and complementary step. System accuracy varies with the distance from camera to target, being typically 20 microns (in X and Y) and 80 microns (in Z), at 1.5 metres. The high accuracy of the system allows the measurement of components and body parts that do not deflect greatly during a K&C test, such as subframes.
“In addition to body movements, there are elements of the vehicle suspension and steering systems that move, flex and twist, in ways that our customers are interested in measuring,” said Dustan. “The K&C Inspect system gives engineers the flexibility to place reflective targets anywhere on the vehicle, within reason, and capture the movements and displacements of the components they are interested in.”
K&C Inspect is aimed at users of both the current SPMM 5000 and the earlier SPMM 4000, provided it has been upgraded to AB Dynamics’ current control system – PowerPMAC. Engineers are currently demonstrating the system to interested parties.
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