Objective Measurement Results vs. Subjective Perception in Vehicle Testing
Vehicle dynamics can be assessed using different approaches. For some, personal perception and experience are the most important factors in analyzing and optimizing the vehicle and its handling. This often applies to experienced drivers in motorsports. In such cases, it is a subjective evaluation. For others, depending on reproducible, technically verifiable measurement data is a crucial point. Within motorsports, for example, race engineers evaluate lap times and perform measurements on the vehicle. In commercial vehicle development, too, engineers are concerned with the chassis, the safety of a vehicle, and its handling. They rely on objective measurement data.
Sensors and DAQs Allow Engineers to Check and Optimize Intertwined Systems
Since numerous electronic control units (ECUs) operate in modern vehicles - ranging from simple driver assistants to ADAS systems (abbr.: Advanced Driver Assistant Systems) and autonomous driving (abbr: AD) - high-precision measurement technology is all the more necessary in vehicle dynamics tests. It records values for the synchronous cooperation of the ECUs and includes the "feedback" of the vehicle. This makes it possible to optimize developments, check processes and ensure that the various assistance systems offer vehicle occupants safety and comfort. This requires highly accurate, responsive sensors that can transmit their measurement signals at a high sampling rate to an equally high-quality data acquisition system.
Safety First: Measuring Wheels Ensuring the Stability of Wheels and their Components
Since the wheels of a vehicle and their components have a central influence on the stability and thus the safety of a vehicle, they are the focus of metrological data acquisition in many vehicle dynamics tests. Via the tires, they form the vehicle's only contact with the road. For vehicle and tire manufacturers, it is therefore particularly important to know which forces and moments act on the wheel from the outside, for example, to investigate different material mixes or tire profiles. The test engineers usually use high-precision measuring wheels for their investigations. For example, 6-Component-WFT (abbr.: Wheel Force Transducer) measuring wheels record the forces and torques of the wheel during various driving maneuvers in the X, Y, and Z directions.
Steering Effort Sensors for Additional Insights
In addition, the drive and steering systems also influence the driving dynamics. The steering behavior of the driver has a direct effect on the wheels and thus on the handling and stability of the car. To obtain precise information about the actions initiated by the driver here as well, steering effort sensors are used. These precisely record various steering parameters, including steering torque, steering angle, steering speed, and steering acceleration. The measurement data recorded in real-time can be used to gain insights into the interaction between steering wheel movement and vehicle response.
Insights Into Material Wear and Component Tuning with Fatigue Testing
Furthermore, fatigue tests on chassis components - which include the steering system, drivetrain, and wheels - can be used to gain important insights into vehicle development, including, for example, the causes of increased material wear that compromises a vehicle's safety. Particularly during dynamic driving maneuvers, the wheels, steering system, and drive axle are subjected to high stresses. A sensor system that records speed and torque directly at the axle shaft makes it possible to calculate the mechanical power from both values. By comparing the power input and the effective power, efficient tuning can be calculated.
Robust Sensor Design for Temperature Fluctuations and Harsh Environments
An important aspect in the selection of sensor technology is insensitivity to external influences such as climatic changes. Temperature changes, for example, must not have any significant influence, nor must humidity. Any precipitation such as rain or snow must not affect long-term measurements, nor must dust, mud, stones, etc. that are stirred up by the ground. These are the best conditions for testing vehicle dynamics all year round, under all seasonal influences.
