Workbike research
news comment makers operators resources research free ads	PedalLine, a new VeloTaxi concept by Charles Henry, Urs Michel and Theo Schmidt ABSTRACT The PedalLine concept is a recent approach to establish semi-public transport on a collective human-power basis. The conventional rickshaw-concept works well for one or two passengers in flat terrain and short trips, but with its poor power-to-mass ratio is unsuitable for hills, and with its high driver-to-passenger ratio is unsuitable and uneconomical for mass transport. PedalLine could offer a wider range for transporting people and goods economically by the application of extra energy provided by passengers and/or by motors. The modular use of interconnected vehicles in a virtual train composition is an inherent characteristic of PedalLine and offers maximum flexibility. Different moduls can be equipped with different types of extra energy: "active" and "passive" passenger moduls, "phantom trailer" luggage moduls, etc., and used according to conditions and demand. Of prime importance is the motivation of "active" passengers in multi-person vehicles with suitable feedback as a "reward". This is a whole area of research which has only just begun. INTRODUCTION - DEVELOPING THE VELOTAXI CONCEPT Vehicles for collective human-powered transportation are proposed and built from time to time. The first were tandems for up to 5 people used for pacing track-racing cyclists. (Later these pace vehicles had less people and an auxiliary electric motor, probably the first use of electric power-assisted bikes.) Tandems were lengthend to ridiculous lengths, often with several people side-by-side (sociable), making a kind of human-powered bus. Because of the scaling rules (ants and elefants!), such vehicles require a very heavy-duty construction and of course strong motorcycle or car wheels. Therefore in spite of the reduced air resistance per person, they are less efficient than single bikes, especially uphill and if there is not a full crew of strong riders. Such vehicles are used for fun and for promenades on special occasions and are not usually suitable for serious transportation. Rickshaws, on the other hand, were always designed for transporting people, but most old and new designs both share the problem that the passengers cannot contribute to propulsion, giving rise to hard work for the chauffeur up any incline. In traditional rickshaw areas the chauffeurs are usually poor and heavily exploited, whereas in high-waged western countries rickshaws cannot economically compete with ordinary taxis except for very short or easy trips. However, one has only to visit parts of London where most of the traffic consists of loud and stinking taxis and buses to see that there is a real need for a more pleasant alternative creating no noise and fumes and using less space. Individual cycles and velomobiles already meet these conditions but are not used by a majority of the population for various reasons. One of these is that for many it is more pleasant to be to be driven or guided around than having to actively make one's own way, especially in unfamiliar or crowded surroundings. It is not so much a question of physical exertion, but rather of the mental effort required to find the way and navigate. Arriving in an unfamilar city or town with a specific destination in mind, it is much less mental effort to take a taxi than study maps and walk, cycle, or use public transport, which additionally requires studying the bus plans or whatever. Of course it also involves less physical effort to take a taxi, but we think that this is not what counts, especially for short trips. The same effect applies to sightseeing. It is much easier to take a guided bus tour than to find everything oneself. As buses are not really pleasant, some cities offer sightseeing services with open carriages pulled by a tractor desguised to look like a plastic locomotive or even worse travesties of good taste. However they work well, going along slowly enough, also in pedestrain areas, that one can concentrate on taking in the surroundings and seeing more detail than the tourists trapped in regular buses confined to the main streets. A similar effect is produced with the "Thuner Tramplewurm", a kind of human-powered virtual train consisting of a tricycle followed by 8 trailers for one person each, used for city tours of Thun, mostly in pedestrian areas. This concept was invented by Albert Levice, an artist. The vehicles work very well for their intended purpose. The trailers track almost perfectly, i.e. each follows almost excactly in the path of the lead vehicle. This way, the narrowest and most crowded areas can be traversed in spite of the great length. However, the good following is at the cost of stability: the maximum safe speed is 15 km/h or so. Also, the vehicle is rather large and unwieldy in relation to the number of passengers and is not efficient transport space-wise. With these facts in mind, one of us (Urs Michel) proposed the PedalLine velotaxi for use with the Swiss national exhibition Expo.01 in 2001. The concept is again modular, with a lead vehicle and several trailers. In contrast to the long and narrow Thuner Trampelwurm, the PedalLine is to be a sociable (two people side-by-side), giving a more compact and street-usable vehicle. The idea is to have different modules: trailers with and without pedals, some with extra energy and power amplification and perhaps some using the "phantom" trailer effect. These can be quickly combined to any configuartion desired depending on the use. The "phantom trailer" is a concept invented by Andreas Koenekamp [Human Power 46], involving a power system controlled in a way to follow the speed of the leading vehicle exactly, thus neither pushing nor impeding the vehicle in front. The "power amplifier" is a power system controled by pedal sensors and able to act like a servo increasing the human power available by a desired function, combining riding pleasure and economy. This was developed by several people, notably Michael Kutter (Velocity) and Alan Abbott (see elsewhere in these proceedings). The most promising uses are probably the special purposes to do with sightseeing and in pedestrian areas. Standard taxi use involves severe competion from conventional taxis which can travel greater distances and routinely don't charge for the return trip. Mass travel, on the other hand is better left to buses or motorised modular vehicles allowing people to stand or sit close together. Hotel transportation is another promising possibility, but only if the vehicle image corresponds to that the hotel wishes to project. Although private family-owned velotaxis would offer a most flexible and safe solution for everyday use (eg. shopping), this is in direct competion to ordinary cars which offer more power and features for the same price, so that the market will be limited to health and environment-concious people as well as those not in posession of a driving licence but still wanting a family vehicle. GENERAL REQUIREMENTS Psychological considerations: appeal to customers, design outline People are both loathe to see a "slave" labouring directly before their eyes but also to work too hard themselves. For the first, being able to pedal themselves will remove this inhibition at the cost of thinking to appear silly, so that there must be a choice between pedalling and non-pedalling places. For the second, this is of no consequence if there are few gradients and the trips are short. Otherwise, an extra-energy concept of some sort is required. Very important is the vehicle design. The fleet of 4 "Thuner Trampelwurms" are mobile "works of art" and treated as such (The inventer artist indeed has no interest in having these vehicles produced or even showing up at the Festival of Human Power.) Companies such as Brox and Seat of the Pants are producing modern designs with some appeal and probably the only reason that eastern rickshaws are not even more heavily decorated is that they are already quite heavy. It has not yet been proven that people feel inclined to use this type of transport. How could we then expect anyone to buy such a vehicle? We feel that it is first neccessary for larger organisations to operate such vehicles as a form of semi-public transport. Costworthiness It is clear that such specially produced vehicles cannot compete costwise for the moment with cars or bicycles produced in vast numbers. Maintenance costs can also be expected to be rather high per distance. The idea of flexible modularity is meant to provide the best solution for a particular situation, saving both effort and wear and tear, and allowing modules to be shared within a small fleet of vehicles. Production costs depend strongly on the number of items produced. Therefore combining one or two specific moduls in a vehicle-composition rather than producing different vehicles for every single use could help cut costs considerably. Safety and Legal Requirements There is no legislation for workbikes or velotaxis in most countries and although the very long "Thuner Trapelwurm" is permitted as a "bicycle" by the Swiss authorities, it is likely that the first serious accident will result in a review of this, and vehicles wider than one meter are not presently permitted, which is just slightly too small for the comfort and stability of "sociables". Most authorities frown upon velotaxis either because they think they are backward or because they think they are dangerous. As soon as motors are added, even very small ones, it becomes very difficult and an enormous amount of effort and patience is required to get official permission. There are several reasons for this: - Such vehicles are compared to conventional motor vehicles, which are much more heavily constructed and offer more passive safety (mechanical protection of the riders), rather than to the bicycles which might be used instead, which offer negligible passive safety. - The law does not differentiate enough between internal and external safety, i.e. between the safety for vehicle users and other road users. A velotaxi which clearly offers less mechanical protection than a car is not "exonerated" by the fact that it is much less dangerous to others by virtue of less mass and a slower speed. Although the critical role of mass and speed in traffic accidents is understood, society is prepared to accept an enormous loss of life through vehicles protected by established interests and has little interest in aiding the development of the very vehicles which might help, because they are considered "funny" and not taken seriously. - Manufacturers of cycle components and vehicle constructors do not help by producing occasionally very substandard components and vehicles; the areas of lights and brakes are notorious. Although the main subject of the last Velomobile Seminar in Switzerland was Safety, there is no evidence that this subject is taken seriously, e.g. many recumbents still sport the dreaded "circular saws" in front and "castration devices" as the support for the front derailleur. VEHICLE CONCEPTS In its most basic form a velotaxi consists solely of a "Lead-vehicle" with one driver and eventually one or more passengers. It can be: - unpowered - simply power-assisted, used only for hills - sensor-type "human-power amplifier" equipped There are several suitable models commercially so that it is not necessary to develop totally new vehicles. In contrast, only the unpowered trailer module-type can be bought "off-the-shelf"; the rest must be especially developed: - unpowered luggage - unpowered passenger "passive" - "phantom-concept" applied to either of the above - passenger pedal "active" - sensor-type human-power amplifier applied to "active" The decision whether to include extra-energy depends on the conditions of use. In completely flat terrain it will not normally be required. If people are not willing to contribute to the motion by pedalling, the velotaxi concept would fail even if extra energy was added. On the other hand extra-energy would be of substantial help where longer or steeper gradients occur, or with a poor power to mass ratio (lots of cargo or on the way back from taxi-duty), or in especially windy areas. A single motor installed in the lead-vehicle should deliver enough traction for these conditions. Powered trailer modules are of course also possible but present a whole range of problems such as higher complexity and cost and difficulty of control. The concept of multiple "phantom" trailers is however intriging and should definately be explored. With a train of two-wheel trailers pulled by a lead vehicle, you can have either perfect following (each vehicle follows exactly in the path of the first) and zero stability (the yawing and pitching motion of ALL trailers has to be held by the lead vehicle, severely limiting the safe speed), or good stability and poor following. The "Thuner Trampelwurm" is a careful compromise also using hydraulic dampers. The following is not perfect but very good, with a turning circle of less than 6 m possible (vehicle length about 18m!), but the highest safe speed is about 15 km/h. Above this, a snaking motion starts to develop and braking can result in accordeon-like jack-knifing. With the PedalLine, we aim at not more than about 4 trailer modules and speeds up to 30 km/h. This allows up to 8 people to be transported, or a few less people including some on wheelchairs and some luggage. The weight should not exceed 20kg/person. Special attention must be paid to achieving smooth automatic braking with overrun brakes operated by the trailer hitches. Modularisation of the construction is essential for several reasons: - using standard production groups (eg. disk-brakes) is cost-efficient. - new types of modules can be introduced without redesigning the whole vehicle. - maintaining vehicles and replacing defective parts is easy and inexpensive. PERSPECTIVE ON BUILDING THE PEDALLINE VELOTAXI Because we have not yet been inundated with interest from the Expo.01 people or even the Festival of Human Power people (with both of which some of the authors are associated, making lobbying difficult!), and our own capabilities are strictly limited, there is not a single PedalLine constructed yet (time of writing). Present activities are: opening financial resources, (e.g. cooperation with SwissMove), cooperation with the ZEM team (2 or 4 people, 4 wheels, to be seen at the Festival of Human Power), cooperation with the Engineering School of Biel/Bienne who plan on using the concept for project work, and trying to get one example going, consisting of a lightly modified version of the two-person sociable recumbent tricycle GEM, produced by Peter Ross and Crystal Engineering, which may be ready by the time this paper is presented. We are convinced that the PedalLine velotaxi concept is an ideal solution for applications between strictly private vehicles and public transportation, especially where it is desired to preserve the quality of life in areas not yet completely spoilt by conventional motor vehicles, or in pedestrian areas where the distances are large enough to offer a bit of active luxury to weary bones. Although it is a vision, it is not utopian, and only requires to be carried out with existing technology. The Extra-Energy bit, although not strictly necessary, can expand the usefulness of the concept to the point where it might be taken seriously enough to make a difference. The modern electronic concepts of power-amplification, phantom trailer, and reward-engineering will make such vehicles a pleasure to use. back to the index