A Japanese vehicle OEM has purchased an SPMM Plus (Suspension Parameter Measurement Machine), AB Dynamics’ newest kinematics and compliance test machine. The unit is currently being installed.
Conventional K&C machines manipulate the wheels of the vehicle to create the movement and force inputs to the suspension system for evaluation. The SPMM Plus utilizes a moving center table design that manipulates the car’s body to generate the necessary movement and force. This design means the ground plane (road) remains fixed when simulating vehicle cornering and braking to replicate on-road vehicle behavior more accurately. According to the company, the benefit of this architecture is the measurement equipment connected to the vehicle’s wheels remains relatively static. Compared to traditional K&C systems, the travel being measured is an order of magnitude less and the loads being received to the cells are direct, resulting in a highly accurate measurement solution.
The table is precisely controlled in six degrees-of-freedom by precision electromechanical actuators, which enable a combination of roll, pitch, bounce and yaw motion to be applied to the car body. As a closed-loop system, it requires no iteration to reach the desired drive commands, which significantly reduces testing time. Another benefit of electromechanical actuators is that the machine does not need to be housed in a separate control room for safety reasons, which is required for a hydraulic machine.
AB Dynamics has provided a safe, clean and quiet working environment for operators, reducing the cost of installation and maintenance – but also enabling users to closely inspect the suspension in action.
It can also be used as a moment of inertia measurement system to quantify a vehicle’s center of gravity (COG) and moment of inertia (MOI), and as such, is two machines in one. Due to the moving body fixed ground design, the vehicle can be subjected to the full axis rotation required to generate the COG and MOI much faster and more accurately than conventional machines. As a result, the SPMM Plus generates all the necessary chassis-based data required to create and correlate virtual vehicle models. In this latest version of the SPMM, it is also possible to measure large sub-systems, such as battery packs or electric drive units.
In terms of future-proofing, to cater for the broadening variety of vehicle sizes, particularly longer and lower electric vehicles, it features a suite of table extenders. In addition, it is fully digitized, running a new and optimized control system, including a high-bandwidth EtherCAT real-time protocol, which is essential for HIL testing.
Its modular architecture enables easy creation of different test setups and upgrades. For example, this includes the ability to speed up the rig. Increasing the standard speed from 140mm/s to 280mm/s at test frequencies up to 5Hz enables the influence of the damper at the wheel to be explored.
“The industry is shifting rapidly towards virtual testing and validation, and the SPMM Plus is a key tool in that process. Its superior level of accuracy directly translates into better correlating vehicle models, which can be exported in one click directly into the popular modeling packages. Importantly, in this latest generation of the SPMM, we have also made it hardware-in-the-loop capable, further increasing its value in an OEM’s virtual development toolchain,” said Matthew Dustan, director of laboratory test systems at AB Dynamics.