# Wiper screen wiper mechanism calculations

1. May 7, 2012

### hamerish

1. The problem statement, all variables and given/known data

In a high school project we have been given the assignment to design the mechanism to transform the a rotary motion into the oscillating of a wiper blade. I'm a bit confused as to how to go about the problem..

I have been given that there is a closing force between the wind shield and the wiper blade of 50N, and coefficient of 0.8. I need to calculate the power and speed of the motor required to drive the mechanism at one complete cycle per second.

I think I need to calculate the friction generated at the wiper blade, then calculate the torque of the wiper arm. Im guessing then I can calculate the power.

Im just not sure what equations I should be looking at and in what order to use them.

2. Relevant equations

3. The attempt at a solution

2. May 8, 2012

### RTW69

I would do a little experiment. Go out to your car with a ruler, stop watch and protractor. Measure how long the wiper arm is, time for one complete cycle and the angle the arm makes for one complete cycle. Now you can calculate the angular velocity of the wiper arm. That might be helpful for the motor speed. I am assuming the closing force is the force is the force the wiper blade applies to the windshield (normal force) and the coefficient of kinetic friction is 0.8. Calculate the friction force, torque and power.