Steering system design proposal for autonomous bikes and scooters
The Need and Demand for Autonomous e-bicycle / kick-scooter
Micromobility refers to a range of small, lightweight vehicles operating at speeds typically below 25?km/h (15?mph). Micromobility devices include bicycles, e-bikes, electric scooters, electric skateboards, shared bicycles, and electric pedal assisted (pedelec) bicycles
?In supply chain management and transportation planning, the last mile is the last leg of a journey that involves the movement of people and goods from a transportation hub to their final destination. Taking the packet from home in logistics, or people arriving to a terminal hub from home is called the first mile but refers to the same issue.
?Besides the proposed management solutions such as Improve Customer-Warehouse Proximity, Technology for Delivery Optimization, Optimize Delivery Vehicle Routes and dynamic vehicle routing, Communicate With Customers in Real-time, effective Real-Time Delivery Tracking System, recently, e-bikes and kick-scooters, scooters and motorcycles have been used effectively to reduce costs and protect the environment.
Cities really hate when scooters park their vehicles on the pavement.
?An autonomous bike is a self-balancing which assist the bike to navigate its journey by taking appropriate actions according to the parameters detected by the sensors. Autonomous scooters could one day independently move themselves to a better parking spot or a neighborhood where there's more demand. These unoccupied vehicles, increasingly known as "ghost scooters," might even drive themselves to pick up a rider, similar to an Uber or Lyft car. In some cases, humans in a tele operations center would guide the scooters across streets and down sidewalks.
?Autonomous electric bikes and scooters can take themselves to charging points – such as a home robot vacuum cleaner. Currently, both missions require trucks and vans to collect and deliver electric bikes and scooters. Autonomous driving will eliminate this requirement, reducing labor and fuel cost and emissions.
?Nowadays self-driving car and truck companies are delaying deployments as they work to prove their complex technology is safe.?Scooters and bikes are lighter and slower than cars and trucks, making them simpler and cheaper to automate and operate remotely.
Companies like Spin, Helbiz, Beam, and Voi are already testing camera-based real-time driving systems developed by brands like Drover AI and Luna, which can detect when a driver is driving on a pavement—inconvenient if there is a fork in the road—or are about to bump into a pedestrian, and even have the ability to stop. is doing. PathPilot is powered by artificial intelligence and computer vision, using onboard cameras to precisely detect sidewalk, street or bike lane riding. It can also verify parking in real-time and reduce e-scooter clutter. Others like Superpedestrian and Bird use a highly accurate location-based approach to implement similar advanced driver.
?Uber is working on autonomous electric bikes and scooters, opening its robotics division to work on just that. The new Jump bikes have a number of features mostly related to self-diagnosis and repair features.
?Manufacturers of autonomous bikes are developing models that ensure improved safety of riders. Yearly, millions of motorcyclists encounter crashes.
?Bird and Lime attracted lawsuits from injured riders, and passionate animosity from lots of people who encountered the dockles scooters that were left in the middle of sidewalks.
?Gyroscopic flywheels and balance pegs have been experimented with in the past for similar applications, but these aren’t on shelf ready solutions. One of the problems is:
?A single-track bicycle, scooter or motorcycle cannot turn directly, but can turn only after side leaning or counter steering
?It can turn, only if the driver leans to the side (effective at low speeds but not effective over 20 km/h) or does the contra-steering maneuver, he can only then make the turn after.
The Wright brothers were bicycle mechanics, and after numerous experiments with bicycles they figured out how to control the plane in the air. Wilbur Wright explained the counter maneuver this way: I asked dozens of cyclists how they turned left. I haven't come across a single person who expressed it correctly when first asked. They said they almost always turn the handlebars left to turn left and as a result they turn left. But when they questioned them even more, some agreed with the explanation that they first turned the handlebars a little to the right and then turned the handlebars to the left while the machine was leaning to the left, making the turn as a result.
People are aware of it or not, but there are 1 billion bicycles in the world today and everyone can cope with this challenge. Gyroscopic flywheels used to imitate?a human rider's body leaning, and AI can certainly do counter-steering maneuver as a human.
?One way to skip over the trouble is to use 3 wheeler scooters. The MIT Media Lab City Science group proposes a solution?: Bicycle has a mechanical attachment that allows it to shift easily from bicycle mode (when in use) to tricycle mode (when the user dismounts, and the bicycle rides to its next destination). The bike transitions from one configuration to the other using two linear actuators that separate and rejoin the wheels as needed.
But should we continue to keep this old design which have deficiency or should we start with a new design that does not need counter steering or body leaning? Neither body leaning nor counter steering does not enable make a turn directly, but turn can be done in second phase of the maneuver, and if we are aiming to prevent or decrease accidents by using autonomous bikes, better find a direct way of turning instead. If we develop autonomous bikes in order?to reduce accident risks, we should correct the design first.
?In the case of a collision risk:
?If the single tracked vehicle is already in the middle of a turn, that means the bike is already leaning and turning to one side, using the brakes will increase the leaning slope and decrease the radius of the turned circle, so you will have a 50% probability of avoiding impact or directly heading to object.
?If the your turn and position of object is not?good for breaking, then you should throttle instead of brake, but if you don't successfully escape the collision, later on-camera witnesses will say you choked and crashed.
?Or you can try to counter-steer, but if you don't make it in time and you crash in the middle of your maneuver, all the cameras and witnesses will see that you're steered wrong, headed to the target and crashed.
?What else can we do? All single-track, front-wheel steering bikes, scooters, motorcycles suffer from the same problem. For inspiration, we can check some other vehicles or gadgets that are not single track but shome-how behaves like a single track, and and makes more succesful turns.
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Why/how do Motorboats lean inward, which is the needed side and the turn done perfectly
Imagine a small motorboat, turning left, looking back at the waterline. To turn left, there is a force applied to either the rudder or the propeller (if outboard) to the right. This force makes the turn by swinging the stern to the right. This turning force is applied below the center of buoyancy, somewhere below the waterline. In effect, the turning force creates a counterclockwise bend in the boat along the center of lift, thus tilting the boat. Here, the propeller is well below the center of gravity with respect to the boat, and the center of the buoyancy force (middle of the hull volume) affecting the boat is also quite low relative to it.
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This maneuver?looks good for starting a turn without need to body leaning or counter steering.
?We can copy this to current single track vehicles, if we design them to have 2ws, then we can start a turn with the rear Wheel steering, so that?if you want turn to the left, rear Wheel turns to the right, turning the chassis frame to the left, meanwhile because rear Wheel pulls the vehicle and rider to the right from the rear bottom, that will lean the vehicle and rider to the left which is what we to turn and balance centrifugal forces
?A bicycle can pass in a bend only when the combined center of mass of the bicycle and the rider tilts into the turn at an angle appropriate to the speed and radius of the turn:
?θ = arctan ( v ^2 / r )
?Here v = velocity, its squared, r = radius of the rotation if it is to go at this angle continuously, g is the gravitational acceleration.
?We can imitate a turn of a motorboat for initiating a turn without a need for counter steering or body leaning, if our bike is capable of steering from the rear. Now lets see what to do after the turn started, how to keep balance more stable?
Let’s look at skiing and snowboarding for observing the behaviour within the turn.
?Telemark skiing is a skiing technique that combines elements of Alpine and Nordic skiing, using a squatting motion on downhill skis. Telemark skiing is named after the Telemark region of Norway, where the discipline originated. Sondre Norheim is often credited for first demonstrating the turn in ski races, which included cross country, slalom and jumping, in Norway around 1868.
?The stem christie or wedge christie, is a type of skiing turn that originated in the mid-1800s in Norway and lasted until the late 1960s. It comprises three steps: 1) forming a wedge by rotating the tail of one ski outwards at an angle to the direction of movement, initiating a change in direction opposite to the stemmed ski, 2) bringing the other ski parallel to the wedged ski, and 3) completing the turn with both skis parallel as they carve an arc, sliding sideways togethe
?The parallel turn in alpine skiing is a method for turning which rolls the ski onto one edge, allowing it to bend into an arc. Thus bent, the ski follows the turn without sliding. It contrasts with earlier techniques such as the stem Christie, which slides the ski outward from the body ("stemming") to generate sideways force. Parallel turns generate much less friction and are more efficient both in maintaining speed and minimizing skier effort.
The parallel turn was invented in the 1930s by Austrian ski racer Anton Seelos from Seefeld in Tirol.
A carved turn is a skiing term for the technique of turning by shifting the ski onto to its edges. When edged, the sidecut geometry causes the ski to bend into an arc, and the ski naturally follows this arc shape to produce a turning motion. The carve is efficient in allowing the skier to maintain speed because, unlike the older stem Christie and parallel turns, the skis don't create drag by sliding sideways.
Jurij Franko graduated from the University of Ljubljana with a degree in engineering in 1983 and joined Elan in '87 as laboratory manager. In 1988 he had the idea of a deep side cut ski and his colleague Pavel Skofic calculated a suitable flexible model. They organized a project called Sidecut Extreme – SCX – and started building prototypes. Franko's calculation was simple: "Choose the turning radius - 10 meters for example. Choose the speed at which you want to ski - 5 meters per second for example. Calculate the centrifugal force and bank angle as you would on a bicycle.
Snowboarding rocks the scene In the mid-'70s, something dramatic happened: snowboarding.
Around 1979, Head's chief engineer, John Howe, and chief marketing officer, Gary Kiedaisch, came up with the Natural Turning Radius concept, where short, agile recreational skis would have a slightly deeper side cut than the factory's long high-speed cruise and racing skis. The idea hit the market in 1981 when the 180cm Head Yahoo (92.5-71.5-80mm) with a 7.3mm side cutoff offered a turning radius of about 35m.
A carving turn can be distinguished by the continuous "pencil line" mark remaining in the snow. This indicates that only the edge of the board is in contact with the snow and there is no skidding during the turn.
There are too many physical explanations and formulas regarding carving turn on internet.
We have remembered Carving Turn and Skidding Turn, if we look at today's front wheels single-track vehicles turn is more like a skidding turn, not a Carving Turn, and thus do not benefits of maintaining balance and speed. If you look at?the illustration below, (excuse me for the quality of the drawing):
The 1 ws bike shown to the right of the circle : The bike frame is not well aligned with the circle that?it is turning, so movement and speeds vector not in the same direction, because the frame is aligned outwards to?the circle, more steering angle is required to keep the bike in the turn.?The rear wheel is always inside the circle and the front wheel is always outside the circle of the turn. The rear wheel do not follow the front so it looks rear wheel is dragged somehow. ( In a carving turn, rear/tail follows precisely the front/head so that after the turn can be distinguished by the continuous "pencil line" mark remaining in the snow. )
However, on the left is a 2 ws bicycle illustrated, chassis is well aligned with the circle, bot wheels steering angle perpendicular to the line crossing the center of the circle, and movement and speed vectors direction However, a 2w bike is shown on the left, the chassis is well aligned with the circle, the steering angle of both wheels is perpendicular to the line through the center of the circle, both have the same steering angles; and the direction of the motion and velocity vectors are the same, and the rear Wheel always follows the front Wheel exactly.are same, and rear Wheel always precisely follows the front wheel.
While turning, you can use the table below, to instantly, correct your leaning and turning circle Radius depending on feedback velocity sensors, leaning sensors, hall sensors.?Here, F:Front, R:Rear, +:increase?steering angle, -: decrease, =: keep as before. For simplicity no magnitudes included but the sistem easily can calculate more precisely.
As a result, i can say that?for single track autonomous micro mobility vehicles, the best steering design is two wheel steering, even though it opposes to what we currently have on our contemporary bicycles and scooters.
One can argue that 2ws is expensive , hard to control, waste of extra components etc. Fort his i can remind 2 examples. Below you see a hoverboard which is sold for 200 EUR or USD and has battery, 2 wheels, 2 controllers for each Wheel, a main-board tilt sensor, hall sensor, balancing capability, all included. The next example is some information about how quadrocopters or multicopters won against a RC helicopter, that also helps.
Today quadrocopter or multicopter drones are widely used today for logistics delivery, photography/ video purposes, but not RC helicopters.
Multycopters?At first glance the helicopter with a single engine and rotor may seem a cheaper and easier-to-handle than a multi-engine multi-copter, howver the multicopter is currently the only option for these industries.?There are othyer industries too :?A drone capable of safely and efficiently inspecting power lines.
Drone Flight Movements
Today as you all know multicopter desing is the winner against RC helicopter for drones used professionally.