1. DYNAMIC SPEED GOVERNORS Seminartopics.info

2. Introduction • With the of aim of dynamically limiting the speed of the vehicle to a preset value. • Presently available option-Static governors. • Static governors have the limitation of setting the maximum speed of the vehicle. • The main idea is to transmit the speed limit for the area to the vehicle, as it approaches an area that has speed restriction, so that the driver can be warned and the speed of the vehicle is automatically reduced.

3. An RF transmitter used in the system transmits a speed limit to the approaching vehicle and the RF receiver inside the vehicle receives this signal. • The comparator present inside the vehicle compares the received speed and the vehicle speed to give an output. • This output can be used to control the governor in the vehicle there by controlling the speed.

4. Components of the System • RF transmitter unit (HT 640) • Sensor unit • RF receiving unit(HT 648) • Digital tachometer unit • Seven segment display device • Display drivers • Comparator • Alarm unit

5. Objective The primary design criteria for this project work were as follows: • Incorporate easily available components • Use cheap and easily worked materials platform • Minimize the weight of the unit • Maintain a level of robustness • Bring about solid design and construction features • Limit the consumption of energy • Modular design

6. Block Schematic of Transmitter Section

7. Block Schematic of Receiver and Tachometer Section

8. RF Transmitting Unit Consists of • A sensor unit • Transmitting unit

9. First section consist of a sensor unit, mono-stable vibrator, astable multi vibrator. • Sensor unit consists of a LDR and photo diode. • Followed by a mono-stable vibrator and astable vibrator.

11. Receiver Module

12. Seven Segment Display

13. NUMBER OF PULSES TO SPEED (KM/HR) CONVERSION Speed in km/hr = distance traveled in km in 1 hr. Also, speed in km/hr = distance traveled in km in (1/a) hr × a Where ‘a’ is the scaling factor and (1/a) hr is the measuring time. Now, distance travelled in (1/a) hr = number of rotations in (1/a) hr × 2π × radius of wheel. Counter value = D1hr = D (1/a) hr × a = 2Nr× π×r×a But counter value = number of pulses counted = Np

14. Hence Np = 2Nr × π × r × a. Np/Nr= 2 π × r × a. We take Np/Nr = 1 i.e. no scaling which means that sensor output is directly coupled to counter. Therefore, 1 = 2 π ×r × a a = 1/(2 π ×r). Here we take the radius of the wheel as, 22.5 cm = 22.5×10-5 km. Value of a = 1/(2 π × r) = 707.35 Hence measuring time = (1/a) hr = 3600 sec/707.35 = 5.08 sec Therefore the measuring time is approximately taken as 5 seconds.

15. Digital Tachometer Unit

16. Display Unit

17. Comparator Section

18. Alarm Unit Figure 11: Alarm Section

19. REFERENCES [1] Development of Electronic Governor and Simulator for the Generating Diesel Engine by Sung Hoon Ko, Hyeong Soon Moon, Jong Cheol Kim, Byeong Yeol Lee, Si Eun Cho, Seung Hyup Ryu, ICROS – SICE International Joint Conference 2009, Japan [2] Comparison and Conversion of Dynamic Models of Speed Governor for Transient Stability Analysis by Li Lin, Kun Zhang, Feng Sun, Qunju Li [3] US Patent 6,167,979, Jan. 2, 2001: Dynamic Speed Governing of a Vehicle by Dennis O. Taylor and G. George Zhu

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