Design and Development of Inline Two Wheeler Self-Balancing Electric Bike

Design and Development of Inline Two Wheeler Self-Balancing Electric Bike

Shreya Sawant

Mechanical Engineering Department Vidyavardhinis college of Engineering & Technology

Mumbai

Omkar Devrukhkar

Mechanical Engineering Department Vidyavardhinis college of Engineering & Technology

Mumbai

Heramb Karpe

Mechanical Engineering Department Vidyavardhinis college of Engineering & Technology

Mumbai

Mahendra Solanki

Mechanical Engineering Department Vidyavardhinis college of Engineering & Technology

Mumbai

Ashish Chaudhari

Mechanical Engineering Department Vidyavardhinis college of Engineering & Technology Mumbai

Abstract- The two wheel vehicles during operation face the issue of balancing especially with untrained rider. Lot of time and fuel could be wasted by learners of the two wheel vehicle in balancing of the vehicle during training period. So, the main objective of this work is to design and develop a self-balancing electric two wheel vehicle which can balance itself with or without rider even vehicle may be in motion or stationary. The controller has two different objectives: to sense the velocity of vehicle in order to operate the actuator for manipulation of rake angle and other is the angle sensor to manipulate the steering angle with respect to vertical. The simultaneous adjustment of these two sensors will maintain the motorcycle stable. The actual set up will be experimented further aiming to balance the vehicle in different condition of loads.

Keywords- Self-balancing; electric vehicle; stability control; trajectory control.

1. INTRODUCTION

   The bike which can balance itself is very popular project in robotics and engineering. There is lot of work going on about balancing bike and some are already done and a lot of work still need to done. The following section is our literature review on this particular topic.

   In 1903, an Irish-Australian inventor Louis Grennan was first to patent a gyroscopic balancing a gyroscopic balancing vehicle.

   In 1912, Russian inventor Dr.Pyotr Shilovsky in collaboration with Louis Grennan developed and designed a two wheel car with gyroscope sitting in the middle of the body of car for maintaining stabilizing force.

   The self-balancing and two wheel robot SEGWAY HT is commercially available and it is invented by Dean Kamen who has design more than 140 systems.

   In CES (Consumer Electronics Show) 2017 Honda unveiled the Riding Assist technology which is the best example and working model of self balancing bike.

   Design:

   Fig. 1. Chassis Geomtry

   Main parameters of motorcycle chassis geometry:

   • Rake ()

   • Point of wheel contact (1)

   • Steering axis and ground intersection (2)

   • Trail (n)

   • Wheel-base (l)

   • Centre of gravity location (hT, lZ)

     Rake angle: Rake angle of the front fork indicates the angle between the steering axis and the ground plane. A smaller rake angle of the front fork results in a greater stabilizing effect on the front fork. The rake angle (angle of steering axis) lies within about 24° to 30° to the ground.

     Steering axis and ground intersection: Point of contact with the ground is indicated as wheel axis intersection perpendicular to the base of a stationary bike at a point of their intersection.

     Trail: Trail is the distance between Steering axis and ground intersection and the Point of wheel contact. Trail has a significant impact on the stability and handling of a motorcycle.

     Wheel-base: Wheelbase is the distance between the rotating axis of the wheels in a straight-line drive.

     Centre of gravity location: Centre of gravity is determined by vertical and horizontal position. What is more important than examining its position on an unoccupied bike is observing the changes with an increasing load.

2. CONCEPT Methods to achieve self balancing are:

   1. Change of trail length

   2. Steering control

   1. CHANGE OF TRAIL LENGTH-

      This picture is of negative trail length. When the bike is running at higher speed the trail length will get reduced. In

      order to achieve stability at low speed the trail length will get increased. This will contribute about 50% of balancing criterion.

      Fig. 2. Bike with negative trail

      SCREW JACK SPECIFICATIONS-

      Fig. 4. Screw Jack

      Length of each arm = L1 = L2 = L3 = L4 = 95mm Length of the power screw = (w1+w2+3) = 350mm

      wl = w3= 161.8 mm , w2 = 26.22 mm Maximum lift of the jack = (hl+p) = 300 mm

      "'' is the angle made by link with horizontal when jack is at its lowest position

      Cos () = (174-13.1)/(170)=18.72°

      W= (load ×g) = (700×10) = 7000N = 7 kN

      Tension, T = W/2 tan ()= 1186.52 N Total tension = 2T = W/tan ()= 2373.05 N

      For a power screw under tension we can take () = 124 N/mm2 for mild steel

      length

      Fig. 3. Bike with positive Trail Length

      Changing the trail length will be achieved by screw jack mechanism which is normally used to lift a vehicle.

      Let d' be the core diameter of the screw. But load on the screw is

      Load = (/4) × (d')2× So,

      2T = W/tan ( = (/4) × d'2×

      2T = 4.5 kN/tan (20.36') = 12123.44 N

      (d')2=(W/tan () × (4/ ×) Hence, d' 4.91 mm

      Since the screw is subjected to torsional shear stress we adopt. d' = 8 mm

      Taking pitch, P = 4mm

      Outer diameter, do = d' + P = (8+4) = 12mm Mean diameter, d = do -P/2 = 12-4/2 = 10 mm

      CONSTRUCTION:

      The jack is connected to the link situated between the suspension rod and the front assembly member. The screw jack is used because of it's capacity to withstand large loads.

      WORKING:

      The jack is device which is useful for lifting heavy loads. The mechanical device is connected to a rod and is attached to the servomotor. This helps smooth operation of the jack to take up the load exerted on the suspension bars. The links on which the jack is connected is firmly welded. The motor when stared makes the opening/closing if the jack within the stipulated time limit of 3-5 sec under varying loads. This movement is button actuated which is deployed at the throttle part of the bike

      CALCULATIONS FOR VARIOUS PARAMETERS:

      Radius of wheel (Rw) = 17 inch = 17×25.4

      = 431.8mm

      MIN Angle of rake (Ar) = 17° MAX angle of rake = 33°

      Rake Offset length (Of) = 15mm Therefore,

      Positive trail length = 9.97cm

      MOTOR SPECIFICATIONS:

      • Torque required = 186.27 kg-m

      • Rpm = 1800 rpm

      • Load capacity =200 N

      • Current = 90V DC

   2. STEERING CONTROL MECHANISM

   Steering control mechanism in which controller controls the amount of torque applied to the steering handlebar to balance the bicycle.

   MOTOR SPECIFICATIONS AND COMPONENTS:

   • Type of motor used- STEPPER MOTOR

   • Load capacity- 10 kg

   • Torque required- 10.33 kg-m

   • Motor controller L298N driver

   • Sensor- gyroscope accelerometer GY-521 MPU6050

   • Uno Aurdino R3

   • Current = 12V DC or 5V

3. EXPERIMENTATION AND GRAPHS-

   On the basis of trail length criterion we performed some experiments and resulted the graph as below

   wheelbase

   wheelbase

   1. Change of wheelbase w. r. t. rake angle

      Wheelbase vs Rake Angle

      1550

      1500

      1450

      1400

      24 25 26 27 28 29

      Rake angle

      Wheelbase vs Rake Angle

      1550

      1500

      1450

      1400

      24 25 26 27 28 29

      Rake angle

      Graph 1. Wheelbase v/s Rake Angle

      As the rake angle is increased the wheelbase increases. This is ideal condition for which the stability of the vehicle can be increased.

   2. Change of clearance w. r. t. Rake Angle

      Ground Clearance v/s Rake Angle

      ground clearance

      ground clearance

      200

      100

      0

      24 25 26 27 28 29

      Rake angle

      Graph 2. Ground Clearance v/s Rake Angle

      The ground clearance is reduced as the rake angle increases. This is due to the fact that wheelbase is increased. This helps in getting the centre of gravity of the bike to a point as low as possible making the bike heavy and thus increasing stability.

      Load

      Load

   3. Time required to achieve max trail

      Load(Kg) v/s Time for max trail

      Load(Kg) v/s Time for max trail

      150

      100

      50

      0

      150

      100

      50

      0

      0

      2 Time in sec 4

      6

      0

      2 Time in sec 4

      6

      Graph 3. Load(Kg) v/s Time for max trail

      Load

      Load

   4. Time required to achieve min trail

   Load(Kg) v/s Time for min trail

   Load(Kg) v/s Time for min trail

   150

   100

   50

   0

   150

   100

   50

   0

   0

   2

   4

   6

   0

   2

   4

   6

   Time in sec

   Time in sec

   Graph 4. Load(Kg) v/s Time for min trail

   Time to achieve max and min trail is done to check the speed at which the mechanism works at different loading conditions.

4. ACKNOWLEDGEMENT:

   It has been a great experience working on this project. However, it would not have been possible without the kind support and help of many individuals and organizations. I would like to extend my sincere to all them.

   We sincerely thank our project guide Dr. Ashish J. Chaudhari for his valuable guidance, constructive criticism and encouragement during every stage of this project. Apart from our subject of research, we learnt a lot from him, which we are sure, will be useful in different stages of our life.

   We owe a depth of gratitude to Dr. U.V. Asolekar, HOD, Department of Mechanical engineering for all the facilities provided during the course tenure.

   We also convey great thanks to our Honorable Principal Dr. Harish Vankudre who helped a lot for completion of this project.

   Last but not the least we would also thank our parents who were always supported us and all those people who have helped us directly or indirectly for completion of this work.

5. CONCLUSION:

   We showed that the front-wheel spin angular momentum and trail are necessary for self-stability, we do not deny that both are often important contributors. But other parameters are also important, especially the front-assembly mass distribution, and all of the parameters interact in complex ways. As a rule, we have found that almost any self-stable bike can be made unstable by misadjusting only the trail, or only the front- wheel gyro, or only the front assembly.

   Conversely, many unstable bike can be made stable by appropriately adjusting any one of these three design variables, sometimes in an unusual way.

   This gives us a method to check for stability by using the steering handle as we see in a cycle being driven at a very slow speed. At very slow speed since it is very difficult to handle the stability thus to counter it we use the movement of the handle bar to counter the fall effect. Similarly here even though increasing the trail length alone cannot give much stability thus the steering mechanism makes an integral part of the mechanism. The various tests made were regarding of trail length and other static constraints. The dynamic constraints such as it's effect on acceleration, deceleration, pitching, rolling are yet to be tested.

   By making a hinged suspension we get a freedom of changing or adjusting the front wheel axis by making the trial length positive to negative.

6. REFERENCES:

(1) Kooijman, J. D. G. , Papadoppulos, J., Meijaard, J.P. and Ruina, A. (2011), A bicycle can be self stable without gyroscopic or caster effect, Science, Vo. 332, pp. 339-42.

(2)MIRAUS JAKUB: Konstrukní eení systému aktivní zmny geometrie motocyklu., Ostrava, 2011. Diplomová práce. VB

Technická universita Ostrava

(3) VLK FRANTIEK: Teorie a konstrukce motocykl 1. Brno 2004. ISBN 80-238-1601-7 BONIOLO, I.; SAVARESI, S. M.; TANELLI, M., Lean angle estimation in two-wheeled vehicles with a reduced sensor configuration. In International Symposium on Circuits and Systems, pp. 2573-2576, Seoul, Korea, 2012.

1. CAICEDO, Y. E. C.; QUINTERO, C. H. L.; DE BRITTO VIDAL

   FILHO, W. A Study of three control approaches for the cyclist robot problem. In 20th International Congress of Mechanical Engineering, Rio Grande do Sul, Brazil, 2009.

2. CAIN, S. M.; PERKINS, N. C. Comparison of a bicycle steady-state turning model to experimental data. In Symposium on the Dynamics and Control of Single Track Vehicles Delft, Netherlands, 2010.