Design And Research On Simulation Loading System For The Rig Of CVT

Both experimental technique and equipment is necessary to research on the Metal Belt Continuously Variable Transmission(CVT). In order to test the performance of CVT on different kinds of drive condition,there must be a experimental equipment to simulate the resistance as the real vehicle's resistance of motion. There are two ways of simulating vehicle's motion resistance: flywheel simulation and electrical simulation. In company with the development of microelectronic technique and the fall of microcomputer's price, the electrical simulation of vehicle's motion resistance become more and more popular. The paper main subjects are the direct current machine and the studying of how to simulate the vehicle's motion resistance on the rig of CVT.1. In order to make a general outline on CVT, this paper introduces CVT's history and the future direction; It also introduces both the simulation method of vehicle's motion resistance and the characteristic and sort of dynamometer at present. Then confirm the method of electrical simulaton and direct current machine as the operating mechanism.2. In order to load at CVT test bed, studies the principle of CVT and loading system. First, analyses CVT's basic structure and gearshift theory. Then studies the principle of direct current machine as the load of CVT's rig, confirms loading scheme of feeding electricity backto electric network and the armature current control mode. Then calculates the characteristic parameter of direct current machine.3. For the purposes of simulating actual resistance of motion, it is essential to establish the model of simulating actual resistance of motion. First, studies the mechanical analysis both of the test bed and actual driving conditon and gives the loading model of test bed through comparing the mechanical analysis. Then designs the test and control scheme of loading system and establishs the simulation model of test and control system. Finally, researches control process of direct current converter, combining the simulation model. Simulate the step test of SSD 590C converter which test bed will use. This simulation verified the SSD 590C converter is met the needs.4. Based on the test and control scheme, designs the hardware and software of the test and control system of the loading system. First, introduce the control system and the principle of measuring current, torque and speed of rotation. Then introduces the type and performance parameter of industrial computor Data Acquisition, senser and converter which consisted the hardware of test and control system. At the aspect of software, studies PID control method, the method of realizing the loading system and digital filter theory. Offered the speed ratio control software diagram, loading control software diagram and digital filter software diagram.5. Undergo a load test on the CVT's rig. In order to studies the issue conveniently, fix the speed ratio when administers the test. First verifies the filtering effect, confirms the relevant parameters of loading model by calculating, measuring or calibrating. Then calibrates the relation between load voltage and objective current. Finally undergo the step-input load test and dynamic load test. The test result proven that the effect meet the needs and the loadingscheme is feasible and correct.