PVGS (Passive Vision Guiding System)

Inspiration

Hsuehshan Tunnel is the best road for connecting Taipei and Yilan. However there is always traffic jams which increases the driving time on holidays. This proposal focus on eliminating the factor of traffic jam to solve the problem. From our experience of getting stuck in traffic jams, the car speed is usually slow when entering a tunnel, and gets higher and higher when approaching the exit. Why? There are three main reasons we have concluded as follow:

People can’t always keep driving at the same high speed because of the difference speed information showing on the dashboard between different cars.
People have difference concepts of safe distance for driving.
Improper brake slows down the car speed behind and causes the chain reaction.

That is, if all the drivers can drive at the best speed with a suitable safe distance, the rate of traffic flow in tunnel can be higher. As a result, how to guide drivers respectively to drive at the best speed with an appropriate distance is the main purpose of the proposal.

雪山隧道是目前台北與宜蘭往返中，最便捷安全的路線。然而，此路線在假日常常造成堵塞的問題，使得行車時間大為增加。本提案提出一種可行且有效率的方式，根除造成堵塞的因素，解決雪山隧道塞車的問題。

從我們自身的塞車經驗觀察到，通常進入雪山隧道時的車速很慢，但漸漸靠近出口時，速度越來越通順。探究其主要原因，是車輛沒有保持最高速度前進、或者不當的剎車動作，造成後方連鎖反應。因此，如能讓所有車輛在安全前提之下，能保持最佳的前進速度，隧道的車流量可以達到最理想的狀況。

然而，最困難之處在於每輛車儀表顯示的車速會有落差，加上每位駕駛主觀認為的安全車距皆不同，因此如何導引每位駕駛至最佳的"車速"與"車距"，是本提案最主要的目標。

What it does

Considering the expanding ability of equipment for cars and the adaptability of new technology for drivers, it is not easy to build a new system on cars. For example, it is inconvenience to update old vehicles or make all the drivers learn new technology devices or new APPs. The efficiency will be decrease much if not every driver take part in the system.

Considering the compatibility for all the vehicles and drivers, and also the driving environments of tunnels are simpler than those of other road types. We design a simple vision guiding system which is able to be installed in the tunnel. This system can provide clear information to guide all the cars moving at the best speed with appropriate safe distance between vehicles. It is the best solution we think! We call it "PVGS” (Passive Vision Guiding System)

考慮到車輛的設備擴充能力，以及駕駛人對於科技方式輔助的適應能力，直接建構在車輛上的控制方法是較為不易的。例如，老舊車輛可能有升級擴充的困難，或者部分駕駛人不習慣使用新的科技配備、手機APP等，若無法使所有駕駛人都參與紓解塞車的系統，效率會大打折扣。

考量到車輛與大眾駕駛人的相容性，且隧道相較於普通道路，是單方向、不可隨意變換車道，相對單純的環境，我們提出一種可建構於隧道本身的視覺導引系統，直接在隧道增加一個簡單直覺的駕駛導引方式，讓每位駕駛可自然的參考視覺指示，維持在最佳的車速和車距狀態，我們稱為主動式視覺導引系統"PVGS (Passive Vision Guiding System)"。

How I built it

Install LED array which display the “light band” along the tunnel. The light band will move forward at ideal speed (E.G. 90km/h), and the distance between each light band is the safe distance for vehicles. Therefore, the drivers can refer to the difference between cars and light band to see if they are at the best driving situation.

Example:

When the car speed is ideal, it is the same as the speed of light band. ( The driver will see fixed light band.)
When the car speed is too low, the driver will notice the light band move forward from his car.
When the car speed is too high, the driver will notice the light band move backward from his car.

PS: The speed and interval of the light band could be modified by control center.

於隧道內沿線鋪設LED跑馬燈，跑馬燈會顯示一段段光帶。這些光帶將會以法定理想時速向前移動，且光帶之間的距離就是理想安全車距。因此，駕駛可參考車輛本身和跑馬燈的差異，來判斷行車速度及安全距離是否保持正確。故會有以下狀況:

當駕駛以正確車速前進，會和光帶速度一致(駕駛視角上光帶沒有前後移動)
當車速過慢時，駕駛會發現光帶超前自車。
車速過快時，發現光帶不斷落後自車

PS:行控中心可依照當下路況動態調整光帶移動速度與距離。

Challenges I ran into

Need to research better light band design for driver to easy reading but less interference. 需要尋找一個對駕駛來說更容易參考但視覺干擾最少的光帶呈現方式
The speed of light band is a fixed number without tolerance, not a range. 光帶移動速度只能固定一個數值而不是一個範圍，無法呈現寬容車速。

Accomplishments that I'm proud of

It is a very simple and clear way (vision guiding system) to solve the traffic jam problem in the tunnel, and it's a very low cost solution. 這是一個非常單純且簡潔的方案(視覺導引)解決隧道內塞車的原因，並只需要低成本即可建置。
The system can be built in tunnel directly, so it's compatible with all vehicles and drivers. No need to learn or update any equipment. 系統直接建構於隧道本身，設計與運作環境單純，不需要駕駛學習操作且通用於所有車輛。
Provide sufficient messages to all cars, minimize the factor of traffic jams. 針對所有車輛的問題給予個別指示，將塞車的可能因子降到最低程度。
We have designed the software in C, and the control logic is able to be transplanted to larger real system in tunnel with little modification. 我們用C完成了軟體設計，控制邏輯僅需部分微調，是可以移植到真實的隧道系統中。

What I learned

The light band signal location need to consider feeling of driver, easy to read and not interfere with safety. And the type of LED icon was discussed and modified several times to make drivers understand quickly and easily.

實際模擬駕駛時發現視覺導引圖示出現的位置需要在明顯但不容易使駕駛分心的視線較前方地面，讓駕駛在專注前方車輛與路況時同時可以感知到提醒。經過多次討論將視覺提醒的介面簡化到清晰易懂的設計。

What's next

We could have different design of "light band" shape, just like fish or flying birds.They could provide same speed reference function and more interesting visual experience.移動的光帶可以有不同的呈現方式，如奔馬，游動的魚群或飛翔的鳥都能達到速度參考的效果。如此除了實際功能外，不斷變化的內容話題有機會成為國際觀光宣傳的加值效果。
How to transplant the prototype to the real application in tunnel? A PLC or an industrial computer can be used as the control center instead of the ARM microprocessor. By using communication way like RS485 or Ethernet, the control center controls the LED drivers and local control units which sense the sensor signal and calculate the car speed. 未來將如何移植原型系統至隧道的應用之中呢? 可以使用可程式邏輯控制器或工業電腦取代原型中的ARM微處理器。藉由通訊如RS485或者Ethernet的方式，行控中心控制LED驅動器以及下位的控制單元，這些控制單元將各自處理部分的感測器訊號並計算車速。
In the future, the PVGS system can be implemented with big data based on the traffic information over the years. According to the current time, car quantity or other factors, establish an algorithm to calculate the best traffic flow in the tunnel and give a best car speed command to control center or host computer. That way, the effectiveness of the proposed PVGS can be the best. 未來將可與大數據做結合，由數年來的交通資訊，根據目前的時間、車輛數等各種因子，建立出即時隧道的最佳車流量的演算法，下達最佳的車速命令給行控中心，將可以將系統的效能提至最高
For real application, the installing location of LED is flexible depending on the professional study of user interface and difficulties of construction.實際隧道內系統燈號安裝位置可以經由更專業的使用者介面研究與施工可行性判斷後微調。

Working sample test

Since the actual system installed in tunnel will be too large, instead we develop a small prototype system with the same control logic function. The control unit we use is ST Microelectronics STM32F3 discovery board with ARM Cortex-M4 CPU, and it is developed in C language. The system structure is as the following diagram. This prototype can truly accomplish all the functions of this proposal, and also simulate the control center to change the car speed command by using the knob. Please refer to the introduction video.

因為實際架設於隧道中的硬體會過於龐大，取而代之地，我們開發了一套縮小尺度的原型系統，但有著相同控制邏輯功能。主控台使用ST Microelectronics的STM32F3 discovery board，核心處理器為ARM Cortex-M4，使用C語言進行開發。系統架構如下圖，此模型除了可確實達到本提案的所有功能之外，也可用旋鈕模擬行控中心改變行車速度命令，請見介紹影片。　　

System Structure 　