Simulation of a suspension and steering system of a car using Hyperworks

1.AIM:

• To build and simulate the suspension and the steering system mechanism for an automobile model moving on a road with the help of different combinations of spring stiffness, damping ratio, and coupler ratio.

2.OBJECTIVES OF THE PROJECT:

• To successfully simulate the automobile model on a road in Hyperworks using systems, attachments and datasets in Hyperworks.

2.METHODOLOGY:.

1 – In MotionView interface , at first dimension units were checked and assigned to SI units and direction of gravity was assigned according to the model to be designed.

2 - To create a basic wheel and knuckle model, Initially four point pairs were created.

1) Wheel centre – (0,-500,0)

2) Knuckle top – (0,-500,700) parametrized X and Y coordinates w.r.t. Wheel centre and Z coordinate with the addition of 700

3) Knuckle CM – (0,-500,350) parametrized X Y and Z coordinates w.r.t. Knuckle top and wheel centre coordinates.

4) Damper centre – (0,-500,525) parametrized coordinates w.r.t. above three points coordinates so that all points can be aligned properly.

2 – Created two bodies for wheel and knuckle.

1) Knuckle – origin at knuckle cm

2) Wheel – origin at the wheel centre.

3 – Now created cylindrical graphics for wheel damper and knuckle.

1) Wheel – 360mm diameter with an offset of (-105)mm.

Parent body – Wheel,

Origin – Wheel centre, along the Y direction.

2) Knuckle – 30 mm die.

Parent body – knuckle,

Origin – wheel centre, along with knuckle top direction.

3) Damper top - 60 mm die.

Parent body – the ground body, which will be changed to the car body when car graphics will be created.

Origin – knuckle top along damper centre direction.

4) Damper bottom – 40 mm die.

Parent body – knuckle,

Origin – knuckle cm, along damper centre direction.

4 – Created two joints.

1) Wheel to knuckle – Revolute joint –

wheel(body 1) – knuckle(body 2) – origin at wheel centre along the Y direction.

2) Knuckle to the body – Cylindrical joint –

knuckle(frame 1) – ground body(body 2) – origin at knuckle cm along knuckle top direction.

5 – Added three motions to the model.

1) Wheel motion(displacement) on joint –

wheel to knuckle - 10⋅sin(2⋅π⋅time)⋅DTOR">10⋅sin(2⋅π⋅time)⋅DTOR10⋅sin(2⋅π⋅time)⋅DTOR

2) Steering motion (displacement) on joint –

knuckle to body - 10⋅sin(2⋅π⋅time)⋅DTOR">10⋅sin(2⋅π⋅time)⋅DTOR10⋅sin(2⋅π⋅time)⋅DTOR

3) Ride motion (displacement) on a joint –

knuckle to body - 250*sin(2*pi*time)

6 – Added spring damper(coiled spring) entity pair with associated graphics.

Ground body (body 1) and Knuckle (body 2), point 1 as knuckle top, and point 2 as knuckle CoM.

Later gave symmetric properties with the left side as a master side.

Stiffness – 150 Damping ratio – 15 Preload – 0 Free length - 350

Graphic radius – 70 Number of coils – 10 Visualization as alloy

7 – Added motion (Spring damper force) on an entity Spring damper.

Now as the model is created, it is moved to the system

8 – Added a system named ‘suspension challenge’ and cut elements from the model initially created and pasted them to the new system. After the successful creation of system, exported it to the new named file.

9 – Imported Vehicle body system to the model.

10 – Added a point attachment for Wheel centre point and added a body attachment for the vehicle body in the suspension system.

11 – Now selected wheel centre point from the suspension system and parametrized its co-ordinates w.r.t. the attachment added in the suspension system.

12 – Similarly, substituted Ground body from Damper_top graphics, Knuckle to Body joint, and Spring damper entity to the previously added attachment of Vehicle body.

13 – Once the substitution was done, the revised suspension system was again exported and then imported for the creation of a rear suspension system.

14 – From attachments tab in the rear suspension system, substitute wheel center front by the Wheel center rear in the Vehicle body system.

15 – For the body to be fixed, added a fixed joint at Vehicle cg point and between the Vehicle body and ground body.

16 – Added a new dataset named Vehicle parameters. Added two members to the data, one, suspension stiffness, and spring damping. Values were given as

Suspension spring stiffness – 800

Spring damping - 15

17 – Now, the new dataset attachment was added to the suspension front system for the Vehicle parameters dataset created.

18 - In the spring damper entity in suspension system front, values of stiffness and damping from properties were parametrized wrt the dataset members added in the attachment.

19 – To enter similar properties to the rear suspension system, exported the revised front suspension system, deleted the initial rear suspension system, and imported back the front suspension system and named it rear suspension system.

20 – Substituted the wheel center front from the point attachment to the wheel center rear.

21 – Now imported incomplete steering system.

22 – Added two couplers, steering to the left wheel and steering to the right wheel coupler.

Steering to left wheel coupler –between Left cylindrical joint and steering joint – rotational type

Steering to right wheel coupler – between left cylindrical joint and right cylindrical joint – both rotational type.

For coupler between steering and wheel,

the ration was given to be -15, and

for the right to left wheel coupler, it was given to be -1.

23 – Deactivated the steering motion from the front suspension system and modified the steer motion from the steering system to the expression – 30*sin(2*pi*TIME)*DTOR

24 - Imported the road and contact system. Assigned the wheel bodies to the bodies option in the body attachment part.

25 – Deactivated the ride motion and wheel motion in both front and rear suspension systems, and for rear system changed the expression of steering motion such that it will be zero.

26 – Deactivated the fixed joint between the vehicle body and ground body so that a car can be appropriately moved.

27 – In the initial conditions of the model, added velocity in the negative X-direction (-1000 m/s) and Ran the simulation.

28 – System was behaving correctly, and the car traveled on the road without an error.

3.Conclusion -

• Proper values of spring stiffness, damping, coupler ratio for steering system were used along with the application of system distribution , joints , motions and 3D contacts to simulate the results of the car moving on a custom made road.