BioCreativity – Stunt Bicycle Power Assist

Bio-inspiration: The Mantis Shrimp is a marine crustacean native to tropical regions of the Indian and Pacific Ocean. It earned this name because its body resembles a shrimp and its head resembles a praying mantis. It is actually neither shrimp nor mantis and is classified as a stomatopod. The mantis shrimp may reach 12 inches in length, with largest recorded measuring in at 15 inches.

 



One feature that makes this creature very unique and interesting and provided inspiration for a new product is its extremely powerful punch. This punch is reputedly strong enough to break through the glass walls of aquariums.

The mantis shrimp’s punch is regarded as one of the strongest in the natural kingdom. The punch is deployed at blinding speed, with an acceleration of 10,400 g and speeds 50 mph (80 kph) and peak forces of 1,500 newtons from a standing start. The strike is so rapid that it generates bubbles which burst, producing extremely high temperatures. The mantis shrimp uses both of these weapons, its powerful punch and the resultant bubbles, to kill or maim its prey; mainly crabs by cracking their shells.





Video of the mantis shrimp using its punch is available at the link below:

http://www.youtube.com/watch?v=pgvsQ6oNZyo&feature=related

Considering that this feat is achieved under water makes the mantis shrimp’s ability even more impressive. Mantis shrimps are able to achieve such extreme forces by slowly storing muscular energy with a spring and latch mechanism. Once the arm is cocked, a ratchet locks it firmly into place. The large muscles present in the upper portion of the arm contract and build up energy gradually. When the latch is released, all this energy is released at once and the lower arm is launched forwards with tremendous force. An illustration of this phenomenon created by S. N. Patek, W. L. Korff & R. L. Caldwell in Nature is given below. The diagram illustrates the essential components in the mantis shrimp’s arm. In the simplified diagram the red is the strong muscular spring, the latch mechanism is shown in yellow, the blue shapes are the arm, and the four dots show the hinges of the four-bar linkage used to generate this motion.

Proposed Idea: Power Assist for Stunt Bicycles

The mechanism used by the organism to store energy and rapidly release it may have great applications in extreme sports especially bicycling. We believe this will be very useful in providing the extra boost of speed while performing stunt maneuvers such as jumps.

The challenge with these maneuvers is that they require the rider to build up a significant speed prior to taking off. Sometimes the margin of error is small and failure to achieve a high enough speed may result in crashes and injuries. During our research we found that almost 30% of accidents occur due to rider not building up enough speed.

Our proposed solution to this problem is to use an energy storage mechanism similar to the biological system the mantis shrimp uses to for its punch; only in this case it would be adapted as a power assist mechanism to generate extra wheel speed. The aim is to design a device which stores energy generated by normal movements of the cyclist in the form of elastic energy and can release it on demand to provide extra acceleration as desired.

The product would store energy using a strong torsion spring mounted on the rear wheel, and would use a ratchet to ensure that the spring does not unwind prior to desired deployment. The energy would be generated either by various forces applied to the bicycle during use, or may be manually wound to achieve full energy potential prior to riding. The rider would have a manual switch on the handlebars to release the ratchet, activating the power assist of the spring and accelerating the bicycle.

Creative Process: In order develop this idea the team started with individual ideation processes to identify biological sources of inspiration. The group came together, presented these ideas, and through an open discussion explored opportunities related to each. Examples were the mantis shrimp’s punch, plate tectonics, and pheromones. There was an initial set of product ideas, and the group worked to juxtapose some of these to try to find new creative options. This led to ideas such as pheromones to help track customer habits in malls, energy storage for above elbow prosthetics, and considering automobile emissions as a method for distributing deer repellent around roads. Group members then took these ideas and used individual ideation processes to branch off from the central ideas of the group. Several days later the group reconvened to compare their divergent ideas and use those to develop a final central idea for the project. The ideas of the mantis shrimp energy storage and roadway pheromone deer repellent were discussed in detail, considering alternatives within each technology. Through this discussion the group coalesced around the idea of an energy storage / power assist system for high performance stunt bicycles.

There were a series of provocation that spurred the idea of applying the energy storage system on a bicycle. The two most significant provocations are discussed here. The original idea had been to use the system for storing energy to actuate a prosthetic arm, and it was a short leap to consider wheelchairs as a similar handicap which may benefit from a power assist mechanism. This brought the discussion to the realm of wheeled vehicles, and the potential for rapid acceleration was raised. This next provocation led the group to consider high performance situations, which is how the idea of stunt bicycle riding was introduced into the discussion.

After developing the idea it was noted that this is similar to KERS technology used in Formula One racing. KERS stands for kinetic energy recovery system; kinetic energy of a moving vehicle is recovered under braking and stored in a reservoir (for example a flywheel or a battery) for later use under acceleration.This energy is usually used to provide the extra burst of acceleration which can be critical in overtaking opponents during the race.

This is not the same as spring assist technologies currently available for bicycles such as the E-Hub. That spring system is designed to smooth energy consumption by storing energy on the downhill automatically and automatically releasing it as the rider slows down on the uphill. The E-Hub is designed to decrease the average energy output of the rider by smoothing over time, whereas this proposed system aims to increase the maximum energy delivered to the wheels during a high performance situation via a controlled release of the stored energy.

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http://t1.gstatic.com/images?q=tbn:ANd9GcRWAF8k_OsHQ15h3qGTyjGA01a1Su_jCap8nqCqyXcZr6CXPszYew

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRgUmqQ-maI7femKQET6yvYcrwC2nAhkSNYfpFtPOOI2Zt8ORr19IlJHfpiFWuRyUOfjzHw2r_FHjdX5jYSm8zuv93vfhweC5wHwFmpLSxZIaE8cqp9IaSROiJ77jIbA986c5p9UaUQQ9l/s1600/mantis.jpg

http://en.wikipedia.org/wiki/Mantis_shrimp#cite_note-Patek_et_al.-6

http://www.nature.com/nature/journal/v428/n6985/full/428819a.html

http://classic.the-scientist.com/news/display/57731/

http://naturalhistorymag.com/biomechanics/082071/knockout-punch

http://www.nature.com/nature/journal/v428/n6985/fig_tab/428819a_F1.html

C M Illingworth, BMX compared with ordinary bicycle accidents, 461-464

http://en.wikipedia.org/wiki/KERS

http://www.ehub.si/eng/default.asp?stran=opis

BIOC #1 - Individual Ideation - Sensitive Plant

Definition

Mimosa pudica, commonly known as "sensitive plant," "sleeping grass" or "touch-me-not," is a creeping annual or perennial herb often grown for its curiosity value: the compound leaves fold inward and droop when touched or shaken, re-opening minutes later.

Mimosa pudica is a member of the Mimosaceae family. Its name is derived from the Greek work for "mimic" and the Latin word for "bashful" or "shrinking." The species is native to South America and Central America, but is now a pantropical weed.

Features

Mimosa pudica has a thorny stem and pale green leaves resembling those of ferns. The leaves are bipinnately compound, with one or two pinnae pairs, and 10-26 leaflets per pinna. The leaves are known for closing in on themselves when touched or exposed to other stimuli such as fire and wind.

The prickly stem of the Mimosa pudica is slender and upright in a young plant and trails like a ground cover as the plant ages. The leaves grow in pairs on either side of three-inch stems branching off of the main stem.

Reproduction

Mimosa pudica seeds are spread by either water or their bristles, which stick to animal fur or human clothing. Mimosa pudica blooms in mid to late summer, producing fluffy pink flowers that take a spherical shape. Its flowers produce long seed pods, each with three to four light brown seeds and require either bees or the wind for pollination.

Energy Acquiring

Like many other legumes, the sensitive plant acquires energy from an association with nitrogen-fixing bacteria, which live within its root nodules. The plants make use of certain form of atmosphere nitrogen which converted by the bacteria, and then grow upon its aids.

Process of leaflet movement

The leaves of the Mimosa pudica have long fascinated people, because the leaflets fold together on touching, warming and shaking. This plant employs both nyctinastic and seismonastic movements. The first phenomenon is called seismonastic movement due to a rapid change in their internal (turgor) pressure and changes in membrane permeability in the pulvini cells in the leaf regions with rapid movement of calcium ions. It is the temporary movement of a plant in reaction to touch, warmth, or lack of water. This movement is accomplished by an electrical and chemical response in the plant. At night, the leaves also fold and bend, and reopen during the day, termed nyctonastic movements (reaction to absence of light).

l  Function

The opening and closing of the plants' leaflets and the entire leaf are controlled by a fluid filled sac-like structures found at the base of the compound leaf and each leaflet. The swollen base of the leaf stalk is called ‘pulvinus’. When the plant is touched, electrical signals are flashed by the cells. The cells in the ‘pulvinus’ respond to this signal by flushing out potassium and water. With the massive loss of water, the pulvinus bends over and the leaflets fold.

How do the leaflet movement feature work to its advantage?

The ability to fold its leaves may benefit the sensitive plant in three ways. It has been observed that folded and drooped leaves are not attractive to herbivores, and are often passed by in favor of more normal appearing leaves to eat. Plus, the sensitive plant may also fold its leaves in an attempt to exchange less water and prevent to be too dry. The undersides of leaves are lined with tiny holes, called stomata, through which the plants breathe. Plants lose significant amounts of water while exchanging gas through the stomata, so the plant can conserve water by closing off as many stomata as possible. Finally, sensitive plants close their leaves when not exposed to the sun, which the drooped leaves would thus exchange less heat. In what is called a "nyctinastic response" the plant responds to dropping levels of sunlight by closing its leaves, keeping them safe through the night.

Threats:

The sensitive plant is threatened and suffering from pests such as red spider mite, thrips and mealy bugs.

Creative Ideas from the leaflet movement feature

l  Safe Window

Based on the folding and bending feature of the sensitive plants, windows that are able to protect the house from theft or robbery can be developed by applying this leaflet movement function. Basically, the set or device which equipped with such function would not really appeared as plants’ leaves, but only takes advantage of Mimosa pudica’s smart and sensitive feature. Specifically, since the nyctinastic movement would cause drooped leaves during the night. The window would only implement the movement of seismonastic which would react to human’s touch. Once the thief intends to climb across the window and touches the screen, the set will automatically folding or bending like the sensitive plant and thus be able to catch the thief.

l Energy-saving and Thermostatic Greenhouse

      
      One of the remarkable movements that enable the sensitive plant to fold its leaves is seismonastic movement which is the temporary movement of a plant in reaction to touch, warmth, or lack of water. According to the benefits mentioned above from this movement, folded and drooped leaves exchange less heat and water than fully expanded leaves in attempt to become too dry,  hot or cold. This kind of adaptive feature could be used to create an energy-saving and thermostatic greenhouse for farmers and gardeners. The greenhouse could be covered with a fabric that functions like the sensitive plant. By controlling the temperature and moisture automatically like the sensitive plant, this kind of fabric (or other possible materials) would keep the greenhouse at a constant temperature and prevent the seedlings or flowers in the greenhouse from dryness and frostbite.

References:

1.       Barneby, R. (1991). Sensitivae censitae: a description of the genus Mimosa Linnaeus (Mimosaceae) in the New   World. New York Botanical Garden, New York.

2.       Weintraub, M. (1951). Leaf movements in Mimosa pudica L. New Phytol. 50: 357-382.

3.       http://en.wikipedia.org/wiki/Mimosa_pudica

4.       http://en.wikipedia.org/wiki/Thisgmonasty

5.       http://www.mls.sophia.ac.jp/~kanzawa/research-e.html

6.       http://www.hindu.com/thehindu/seta/2001/12/06/stories/2001120600130400.htm