If significant data fluctuations occur during vehicle rolling test machine testing, a systematic investigation is necessary, addressing five dimensions: mechanical structure, control system, sensor accuracy, environmental interference, and operational procedures. Regarding the mechanical structure, the wear and installation accuracy of transmission components should be carefully examined. For example, misalignment of the coupling or excessive bearing clearance can cause periodic mechanical vibrations, leading to data fluctuations. In this case, the coupling position should be adjusted using a laser alignment instrument, worn bearings replaced, and the condition of the drive belt or gear teeth checked, removing any foreign objects to ensure smooth transmission. Furthermore, the frictional resistance between the hydraulic cylinder and piston may increase due to excessively high hydraulic viscosity or residual dirt; therefore, standard-compliant hydraulic oil should be replaced regularly, and the cylinder interior cleaned.
The stability of the control system directly affects data output. Delays in the load control algorithm or failure of the feedback mechanism can lead to uncontrolled load regulation. For example, improper PID parameter settings may cause system oscillations; closed-loop debugging is needed to optimize the proportional, integral, and derivative coefficients to balance the system response speed and overshoot. Meanwhile, aging or poor contact of electronic control components can also cause signal interference. It is necessary to regularly check whether the wiring terminals inside the control cabinet are loose and monitor the control signal waveform with an oscilloscope to eliminate electrical noise. For high-precision testing, the control program can be upgraded to improve algorithm accuracy and real-time response capabilities, ensuring the smoothness of the loading process.
As the core component of data acquisition, the accuracy and anti-interference capability of sensors are crucial. Decreased sensitivity or installation misalignment of torque and speed sensors will directly lead to data distortion. For example, unclean or loose sensor mounting surfaces may introduce additional stress, requiring recalibration of the installation position and tightening with a torque wrench. Simultaneously, it is necessary to check whether the sensor signal lines use shielded twisted-pair cables and ensure good grounding to avoid electromagnetic interference. For high-precision testing, a higher resolution sensor can be replaced, or data reliability can be improved through redundant design. If the sensor output signal is abnormal, its output value under no-load and load conditions should be measured with a multimeter to determine whether the fault is caused by zero-point drift or internal wiring breakage.
The impact of environmental factors on test stability is often overlooked. Vibration interference may be transmitted to the vehicle rolling test machine through the foundation. Vibration damping pads or air springs should be installed at the bottom of the equipment to isolate external vibration sources. Temperature fluctuations can cause mechanical parts to expand and contract with temperature changes, affecting transmission accuracy. The test chamber temperature must be controlled within a constant range, and direct sunlight or direct airflow from air conditioners onto the equipment should be avoided. Power quality is also critical; unstable voltage or harmonic interference can cause load fluctuations. A regulated power supply and filter are required to ensure clean power supply. Furthermore, the presence of high-power equipment or wireless communication devices in the test environment may cause electromagnetic radiation that interferes with sensor signals. Shielding measures or adjustments to the equipment layout are necessary to reduce the impact.
Standardization of operating procedures is also a key focus. Insufficient preheating of the vehicle rolling test machine before testing may prevent the system from reaching a stable state. It is necessary to run it under no-load for a certain period of time according to the procedure before loading. Incorrect parameter settings, such as excessively large speed or load steps, can cause dynamic response lag. The parameter gradient must be adjusted according to the equipment manual. In addition, improper sample installation, such as underinflated tires or misaligned rims, can introduce additional vibrations. A dynamic balancing machine is needed to correct the sample, and it's crucial to ensure uniform clamping force. For equipment used long-term, a regular maintenance plan is recommended, including timely replacement of worn parts and recording equipment operating status to provide a basis for troubleshooting.
If the problem persists after the above checks, aging or damage to core components should be considered. For example, worn carbon brushes in the vehicle rolling test machine motor can lead to poor contact and load fluctuations, requiring regular brush replacement and commutator cleaning. Hydraulic system contamination or cavitation can cause pressure fluctuations, necessitating hydraulic oil replacement and oil circuit cleaning. For critical components, it is recommended to contact the manufacturer for comprehensive testing, and replace core modules if necessary to restore equipment accuracy. Through systematic troubleshooting and targeted optimization, the testing stability of the vehicle rolling test machine can be significantly improved, providing reliable data support for vehicle performance evaluation.
