Thursday, November 1, 2018 · 16 min read
Brake Test On Tractors
This application note shows how Dewesoft products provide an effective solution for quick validation of braking parameters in the field. The mobile measurement instruments and the easy to setup software are used for checking braking parameters according to regulations. At the same time, a similar solution is providing the testing tool in case of future troubles.
The client, a huge tractor manufacturer in Austria, is developing and producing farming machinery including tractors for the worldwide market. With the increasing performance of the tractors (higher velocity) and new regulations, every tractor has to pass the brake test in order to pass the homologation test.
The regulation at the moment is quite basic, in comparison to automotive regulations, because the tractor has to drive either at 40 km/h or 50 km/h (depending on the HP of the engine) and brake to 0 km/h, within a certain distance and achieving certain MFDD factor. At the same time also braking force is a key factor in successfully passing the brake test. It does not include the measurement of the temperature of brake lines and several cycles of braking.
Data acquisition system
DEWE-43A data acquisition system (8 analog, 8 digital channels, and 2 high-speed CAN bus inputs)
DS-VGPS-HS GPS Receiver (100 Hz GNSS receiver with the support of GPS/GLONASS)
Entron force transducer with a range of 2500 N
Dewesoft brake pedal trigger
DewesoftX data acquisition system with brake test plugin
Brake test setup
In the brake test plugin, we have to choose a proper start/stop condition. In our case, it was the signal coming from the brake pedal trigger and the stop of the movement with a threshold value of 1 km/h. Since the tractor was “only” 140 HP, the brake test was performed at 40 km/h. So MFDD, brake distance, stopping time, and brake deceleration were calculated for these conditions.
The display was created for the easier online indication to the driver if the test is valid or not. Therefore all the parameters (MFDD, Brake distance, Start speed, ... ) were compared to regulation conditions with the help of math channels.
Testing engineers were interested in more details, therefore curves like dynamic braking force and velocity are very important to them.
The measurement of this particular model of the tractor has been successful and the tractor has passed the internal check of regulation. The most interesting parameter for the customer was velocity, where they were able to see the swinging of the cabin, which goes up to 5 km/h and will help them with the future development of the stiffness of the suspension. The whole measurement including the setup of the tractor took 3 h (including soldering the connectors of special sensors provided by the customer and comparison tests).