Implementation of Virtual Instrumentation Concept on Tests Rigs 2009-26-0078
Tractor is used as a farm machine for various agricultural applications and non-agricultural applications. These are like land and soil preparation, harvesting, goods transport vehicle for short distances and also as low cost construction equipment. The usage pattern is scattered and largely depends on type of operation, region, and operator driving habits. Due to larger range of usage pattern, there are many challenges for tractor testing and evaluation. The evaluation process starts with field load data acquisition, followed by development of test load cycles and test facilities to simulate the field load conditions in lab with adequate acceleration.
Traditionally for testing of transmission, hydraulics, brake, clutch, gear shifting mechanism, engine test beds are mechatronics (mechanical and electronics) system. These systems having fix specifications so it's not possible to change the configuration. For new field failure simulation some times it is required to change logic or a specification of the test system, this process is very difficult and time consuming. This leads to more product evaluation time.
To overcome this problem new concept was developed in which all fix specification instruments, switches, devices, electronic controllers etc are converted in to software centered variable specification instruments, switches, devices etc. This will completely eliminate vendor dependency. With this concept it is possible to convert the electro hydraulic systems to electrical system or vice versa. The paper describes the implementation of the virtual instrumentation concept on different test systems like transmission test system, actuator controller, servo hydraulic system, gear shifter, test system, brake test rigs, clutch test rig, PTO testing, engine test beds etc., in detail. Virtual instrumentation based systems incorporate (i) Signal processing, (ii) Mathematical model of each component of the system, (iii) development of graphical user interface panels. (iv) Selection of sampling frequency (v) data acquisition, and (vi) diagnosis. Virtual instrumentation is developed in Labview and integrated with sensors. Salient features of the test rigs include- on line data acquisition, on line data analysis, remote monitoring of the test system, post data analysis, visual and audio alarm activation, in case of limit crossing at any time for all channels and fault identification. With this concept soft servo controller, soft dynamometer controller, soft alarm controller, soft throttle controller, soft SFC meter etc., are successfully developed.