Carrier Technologien

    

Was interessiert ? Welche Transport-Technologien werden gebraucht ? Welche Transport-Technologien sind vorhanden ? Zu welchen Transportaufgaben sind sie geeignet ?

Allgemeine Anforderungen Automatisierbar. Mittlere Nutzlasten (ca. 700kg). Möglichkeit zur Aufnahme von Kabinen.

Schienengebundene Carrier ``PRT: Personal Rapid Transit'' Eigenschaften: Mittlere bis hohe Transportkapazität. Mittlere bis hohe Geschwindigkeit. Ultra-leichte Schiene (Querschnitt $\approx 1$m2). Abstand zwischen Verzweigungen oder Haltestellen mehr 300m. Technische Probleme: Sichere und zuverlässige Fahrzeug-Abstandsregelung (Zeitabstand im Sekundenbereich). Effiziente Logistik.

Höhere Kapazität durch kleinere Abstände

3-spurige Autobahn an der Kapazitätsgrenze$\ldots$

$\ldots$ ohne Autos $\ldots$

$\ldots$Abstände verringern$\ldots$

    

$\ldots$PRT einbauen.

Gründe für die hohe Transportkapazität von PRT      Die flächenbezogene Transportkapazität von PRT Systemen ist gross weil: Kurze Fahrzeug-Abstände. geringe Spurbreite (ca 1.50m) Prediktive Logistik kann Verkehrsengpässe vorhersehen und den Verkehrsfluss optimieren. Geringer Bedarf an Park-und Standflächen, da leere Fahrzeuge automatisch zu neun Klienten gefahren werden.

The carrying capacity, expressed in persons per hour is not an obvious quantity to determine, as it depends on a large number of parameters and assumptions. The prime systematic difference between the manually driven car and an automated system is that the car has a much longer break actuation time. The break actuation time is the time between the occurrence of a breaking manuvre of the preceding vehicle and the actuation of the break. This time is for cars approximately 0.8s and for automatic detection and breaking systems in the range of milli-seconds. The minimum time headway $T_{\min}$, that is the time that passes between two successive vehicles must be [6]

$$T_{\min}=\frac{L}{v}+T_{c}+\frac{v}{2}\left(\frac{1}{a_e}-\frac{1}{a_f} \right)$$

The capacity C_v in vehicles per hour is then

$$C_{v}=\frac{1}{T_{\min}}\cdot 3600$$

The parameters are:

parameter	symbol	value
Vehicle length	L	3m
Line speed	v	10-130km/h
Break actuation time	Tc	100ms
Emergency deceleration	ae	0.9g rubber on asphalt 0.65g rubber on concrete 0.2g rubber on ice 0.5g acceptable without safety belt
Failure deceleration	af	ae if preceding vehicle does emergency breaking $\infty$m/s2 if the preceding vehicle stops instantly

For the first simulation we assumed that the emergency and failure decelerations are a_e=a_f=0.5g. For the second simulation we assumed that the emergency decelerationa_e=0.9g and failure deceleration $a_{f}=\infty$m/s² (instant stop or brickwall). For the car we assumed a reaction time of T_c=800ms.

For comparison, a light rail train system (or metro) with 6 wagons per train and 100 passengers per wagon, where one train arrives each 5 minutes has carrying capacity of 7200persons per hour. However, in contrast with rail, MAIT is a distributed transport network and therefore does not need to concentrate the traffic onto lines. Because a MAIT guideways are smaller and more cost-effective than rail, it is possible to install more tracks to cover a certain area. In conclusion, the capacity of MAIT guideway does not need to be as high as the one of a metro line.

The performance difference between the two graphs is due to different safety assumptions: The second graph shows the performance if present train safety criteria were applied ("brick-wall criteria"). However, excluding the case that a vehicle is able to stop instantly, but decelerates at the maximum emergency deceleration, the throughput of the automated system can be improved considerably as shown in the top figure. In conclusion: safety legislation determines significantly the capacity of an automated network.

Optische Wirkung der PRT-Schienen      Mögliche Strategien zur Integration der Schienen in das Stadtbild: 1. Minimierung der Abmasse. 2. Integration in Bahnhöfe, Kaufhäuser, Parkhäuser, e.t.c. 3. Anpassung des Unterbaus an die Stadtarchitektur. 4. Doppelnuztung: Überkopfschienen können gleichzeitig als Dach für Fussgänger- und Fahrradwege e.t.c. dienen. 5. Verlegung in den Untergrund.

Note that unidirectional MAIT guideways have a width of only 1.50m and are comparable in size to larger pedestrian walkways or ``sky-ways''. A city with streets that are protected from sun and rain (such as Bologna, Italy or Bern, Switzerland) is more welcoming to both visitors and inhabitants. Another option are road carriers that do not need any visible guideway and that are slow and can share space with pedestrians. The guideway photos are similar in dimensions to the Taxi2000 PRT [7] system, but this is not an automated Personal Rapid Transit (PRT) system. It is has been built in 1973 by Universal Mobility which was sold to TGI which was in turn sold to Bombardier. In 1996 it was given a refurbishing by Lameroux McClendon & Associates. The vehicle is shown in the frame of the lower photograph. Differences between this system and the projected Taxi2000 system:

• Approximately $120 \times 60$cm guideway - Taxi2000 $90 \times 90$cm.
• I-beam columns with exposed parts - Taxi2000 smooth round tapered columns.
• Stark blue and white colors - Taxi2000 muted colors
• Span about 20m - Taxi2000 the same
• Clearance height 4.20m - Taxi2000 the same. European legislation would require 5.70m when traversing roads.

It is hoped that these photos will provide a general idea of the visual impact of a PRT guideway. Photos taken by Dennis Manning 8. August 2000 at CalExpo - site of the California State Fair, Sacramento, California, USA.

Strassengebundene Carrier AGV: ``Automated Guided Vehicle'' Systems Eigenschaften: Niedrige bis mittlere Transportkapazität. Geschwindigkeiten bis 20km/h. Nutzung von vorhandenen Strassen. Netzwerk mit hoher Verzweigungsdichte. Für Transporte in Gebäuden geeignet. Technische Probleme: Sicherer Betrieb auch mit Hindernissen. Zuverlässiger Betrieb, auch bei schlechte Wetterverhältnissen.

Zukünftige Carrier Eigenschaften: Hohe Geschwindigkeiten mit Magnetschwebe-Technologie, eventuell in Vakuum-Röhren. Tunnel, Brücken oder Unterwasser-Strecken mit Röhren (Durchmesser ca. 1.60m)