出租车计价器毕业设计中英文翻译.doc

1、ABSTRACT1. INTRODUCTIONTransporting people in the morning from their homes to their works and back in the afternoon has become a big problem in big cities especially in undeveloped countries. As a partial solution of this problem, the authorities in some countries had, unofficially, left the taxicab

2、 drivers to carry different passengers to different places at the Same time. For example, a taxicab with four seats may carry four different passengers without any relation between them except that their way of travelling is the same.Accordingly, it has become very difficult to rely on the present c

3、onventional single-channel taximeter to determine the fare required from each passenger separately. Accordingly, an unfair financial relation was created between the taxicab driver, owner, passengers and the state taxation department.Under these circumstances, taxicab drivers force the passengers to

4、 pay more than what they should pay. In some cases passengers had to pay double fare they should pay. With the present conventional single-channel taximeter, taxicab owners are not able to determine the daily income of their taxicab.In some cases (a taxicab with four seats) they may only get one qua

5、rter of the income of the taxicab (collected by the taxicab driver). From which they should pay the salary of the taxicab driver as well as the cost of fuel, minor and major repairs in addition to the car depreciation. As a matter of fact the position of the taxicab owners is not so bad as it seems.

6、 A general agreement has been reached between the taxicab drivers and owners such that the drivers should guarantee a fixed daily income to the owners as well as the paying for the cost of fuel as well as the minor repaires. Even though the taxicab drivers still share the large portion ofthe income

7、of the taxicab. Also with the presence of the single-channel taximeter, it has become very difficult for the state taxation department to know the yearly income of the taxicab and accordingly it has become very difficult to estimate the taxes to be paid by the taxicab owners.In order to face this pr

8、oblem, the state taxation department had to impose a fixed estimated taxes for each seat of the taxicab whatever the income of the taxicab. In this paper, we introduced a multichannel taximeter that can deal with more than one passenger simultaneously. I t should be pointed out that by the term pass

9、enger we mean a one person or a group of related persons. I t should also be pointed out that our proposed multi-channel taximeter is not, simply, a multi display readouts. As a matter of fact it contains logic circuits that automatically changes the fare per killometer of travelling distance or per

10、 minutes of waiting time according to the number of passengers hiring the taxicab. In the following part and as an example, we will present a complete design for a three-channel taximeter.Block diagrams as well as detailed circuit diagrams of the experimental three-channel taximeter are also include

11、d. A prototype has been built under grant from the Egyptian Academy for Scientific and Technological Research.2. AN EXPERIMENTAL THREECHANNEL TAXIMETERTheory of operation of our experimental device to work as an electronic digital taximeter is based on t h e fact thathe speedometer cable rotates one

12、 revolution for each meter of travelling distance.Accordingly, if the speedometer cable is coupled with a speed sensor that generates a single pulse for each meter of travelling distance, then our taximeter could be three up counter modules associated with a speed sensor unit.However, our experiment

13、al taximeter is not simply a three display readouts. As a matter offact it contains logic circuits that automatically changes the fare per kilometer of travelling distance or per minutes of waiting time according to the number of passengers hiring the taxicab. The device may be splitted into two mai

14、n parts: The first is the speed sensor unit which may be located anywhere in the taxicab such that an easy coupling to the speedometer cable can be achieved. The second unit contains the main electronic circuit, the displayand control panel. The unit should be located somewhere in front of both the

15、driver and the passengers.A possible components locations is shown in Figure 1.A. Speed Sensor UnitThe main function of this unit is to supply train of pulses whose frequency is proportional to the angular rotation of the wheels. A possible form of a speed sensor is shown in Figure 2.If may consist

16、of a tj.pica1 permanent magnet sine wave generator with its output connected to a pulse shapping circuit (two general purpose silicon diodes, 1K ohms resistor and a schmit trigger inverter).In order to find some way to detect the movement of the taxicab, the output of the sine wave generator is rectified through a general purpose silicon diode Dl then smoothed by a 1000 F capacitor. The output voltage at terminal Q is then limited to the value of 4.7 volts by usi