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#ActualK_J_M

Posted 10 September 2012 - 12:01 AM

Hello PochyPoch.

I havn't read all of your post but a quick glance brought me to question 4.

To clarify Part 4.

If the car is stationary and spining on it's axis, and the front wheels arn't turned to any steering angle (yaw) but pointing in the direction the chassis points, then each wheel generates +- 90 degrees slip angle. The wheels only have lateral movement. ie they are only sliding sideways as the car spins.

The sign of the slip angle depends on whether the car is spinning clockwise or anti clockwise.

My statement about not generating slip angles was because the car is stationary and no slip angles are generated from the code that uses linear velocities of the car chassis to determine the slip angles. My basic method was using 1 wheel (chassis) to determine the slip angles and Bmarci was using 4 wheels.

Slip angles are generated by the difference between the longitude and lateral velocities of the tire.

The confusion comes from the fact that i was using the car chassis to determine the slip angle and not for each tire.

So when writing your sim, you need to take into consideration the angular velocity of the car and the slip angle that generates for each wheel and the linear velocities of the wheel (chassis , since the wheel is attached to the chassis).

The car can be moving with no angular velocity (moving forwards or sliding sideways), stationary but spinning on it's axis or any combination of the two.

And both situations need to be considered to determine your actual slip angle for each wheel.

The steering angle of the front wheels also needs to be taken into consideration for the front wheels slip angle.

Hope thats clearer.

And best of luck with your game.

I too have made a top down racer.

http://www.trinosis.com/

#4K_J_M

Posted 10 September 2012 - 12:00 AM

Hello PochyPoch.

I havn't read all of your post but a quick glance brought me to question 4.

To clarify Part 4.

If the car is stationary and spining on it's axis, and the front wheels arn't turned to any steering angle (yaw) but pointing in the direction the chassis points, then each wheel generates +- 90 degrees slip angle. The wheels only have lateral movement. ie they are only sliding sideways as the car spins.

The sign of the slip angle depends on whether the car is spinning clockwise or anti clockwise.

My statement about not generating slip angles was because the car is stationary and no slip angles are generated from the code that uses linear velocities of the car chassis to determine the slip angles. My basic method was using 1 wheel (chassis) to determine the slip angles and Bmarci was using 4 wheels.

Slip angles are generated by the difference between the linear and lateral velocities of the tire.

The confusion comes from the fact that i was using the car chassis to determine the slip angle and not for each tire.

So when writing your sim, you need to take into consideration the angular velocity of the car and the slip angle that generates for each wheel and the linear velocities of the wheel (chassis , since the wheel is attached to the chassis).

The car can be moving with no angular velocity (moving forwards or sliding sideways), stationary but spinning on it's axis or any combination of the two.

And both situations need to be considered to determine your actual slip angle for each wheel.

The steering angle of the front wheels also needs to be taken into consideration for the front wheels slip angle.

Hope thats clearer.

And best of luck with your game.

I too have made a top down racer.

http://www.trinosis.com/

#3K_J_M

Posted 09 September 2012 - 11:55 PM

Hello PochyPoch.

I havn't read all of your post but a quick glance brought me to question 4.

To clarify Part 4.

If the car is stationary and spining on it's axis, and the front wheels arn't turned to any angle (yaw) but pointing in the direction the chassis points, then each wheel generates +- 90 degrees slip angle. The wheels only have lateral movement. ie they are only sliding sideways as the car spins.

The sign of the slip angle depends on whether the car is spinning clockwise or anti clockwise.

My statement about not generating slip angles was because the car is stationary and no slip angles are generated from the code that uses linear velocities of the car chassis to determine the slip angles. My basic method was using 1 wheel (chassis) to determine the slip angles and Bmarci was using 4 wheels.

Slip angles are generated by the difference between the linear and lateral velocities of the tire.

The confusion comes from the fact that i was using the car chassis to determine the slip angle and not for each tire.

Hope thats clearer.

And best of luck with your game.

I too have made a top down racer.

http://www.trinosis.com/

#2K_J_M

Posted 09 September 2012 - 11:53 PM

Hello PochyPoch.

I havn't read all of your post but a quick glance brought me to question 4.

To clarify Part 4.

If the car is stationary and spining on it's axis, and the front wheels arn't turned to any angle (yaw) but pointing in the direction the chassis points, then each wheel generates +- 90 degrees slip angle. The wheels only have lateral movement. ie they are only sliding sideways as the car spins.

The sign of the slip angle depends on whether the car is spinning clockwise or anti clockwise.

My statement about not generating slip angles was because the car is stationary and no slip angles are generated from the code that uses linear velocities of the car chassis to determine the slip angles. My basic method was using 1 wheel (chassis) to determine the slip angles and Bmarci was using 4 wheels.

Slip angles are generated by the difference between the linear and lateral velocities of the wheel.

The confusion comes from the fact that i was using the car chassis to determine the slip angle and not each wheel.

Hope thats clearer.

And best of luck with your game.

I too have made a top down racer.

http://www.trinosis.com/

#1K_J_M

Posted 09 September 2012 - 11:45 PM

Hello PochyPoch.

I havn't read all of your post but a quick glance brought me to question 4.

To clarify Part 4.

If the car is stationary and spining on it's axis, and the front wheels arn't turned to any angle (yaw) but pointing in the direction the chassis points, then each wheel generates +- 90 degrees slip angle.

The sign of the slip angle depends on whether the car is spinning clockwise or anti clockwise.

My statement about not generating slip angles was because the car is stationary and no slip angles are generated from the code that uses linear velocities to determine the slip angles.

Slip angles are generated by two methods.

By the linear velocities of the car and the angular velocity of the car.

In my basic sim, i just reduce the angular velocity of the car by a constant friction.

Bmarci, i think, uses his Pacejka calculations to return a friction based on slip angle to reduce the angular velocity of the car.

Either way, a spining car generates lateral forces on the wheels which act to slow down the angular velocity.

Hope thats clearer.

And best of luck with your game.

I too have made a top down racer.

http://www.trinosis.com/

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