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Abstract—The prime aim of this project is to design, analyse and fabricate a double wishbone (A arm) suspension for a hybrid cycle.This project focus on designing and fabricating a suspension system considering stability of the vehicle and comfort of the rider. Thus a double wishbone suspension system is adopted for front wheels. The dynamics of the vehicle and the design parameters are considered while designing, analysing and fabricating the vehicle.
Keywords— A arm, Double wishbone, Suspension geometry, Upright
This is a hybrid tricycle which purely runs on electric and human power. It is essential to develop alternate and greener modes of transportation for the betterment of our future. A tadpole design was adopted with two wheels at front and one at the back.Two drivers can alternatively pedal the cycle.Some of the design parameters are considered for the analysis and then fabrication of the suspension components are done based on it.
A double wishbone suspension system consist of two control arms generally known as upper A arm and lower A arm. Both the A arm is of unequal lengths. These arrangements along with the shock absorber consist of suspension system. A single wishbone or A arm can be also used in various cases.
Design of A arms
Initially material of the wishbone is selected considering strength and cost. To determine various design parameters such as length of wishbones, tie rod length, coil length, suspension geometry is drawn. The designed A arms are then modelled using CATIA software and then analysis is done using ANSYS or CATIA.
The next step of designing is to decide various dimensions of the components of the system. The dimensions are
a)Wheel track: 52 inch
b) Wheel base: 54 inch
c) Camber angle: 0 degree
d) Kingpin angle: 4 degree
e) Sprung weight: 270 kg
A 26 inch diameter wheel is selected.
The specifications of the double wishbones are obtained from the suspension geometry of the vehicle
Upper arm length: 8.16 inch
Upper arm outer diameters: 1 inch 3 mm thickness
Upper arm angle with horizontal: 8 degree
Lower arm length: 8.69 inch
Lower arm outer diameter: 1 inch 3 mm thickness
Lower arm angle with horizontal: 11 degree
The shock absorber is mounted on the upper arm. Upright is designed, fabricated and attached to the A arm by ball bearings.
Considering the optimum cost and strength AISI 1018 mild/low carbon steel is used.AISI 1018 mild/low carbon steel offers a good balance of toughness, strength and ductility.Also it has an excellent weldability.
As per the design parameters, the suspension system for the hybrid vehicle is fabricated. A double wishbone suspension system is adopted for the vehicle considering better maneuverability and control.The components used in fabrication is easy to manufacture and readily available in the market. Moreover the components are easy to assemble and provide less weight.This vehicle can be utilised for internal transportation in big industries, railway stations for the disabled ,for short journeys.This suspension system aids to comfortability to the rider.