How to calculate resultant force for a bike pedal stroke

• Toby
In summary, the conversation discusses a problem involving calculating the resultant pedal force from given variables. The problem involves using equations and a diagram to find the solution, and the conversation also mentions a coding task to analyze data for 10 cyclists.
Toby

Homework Statement

To calculate the resultant pedal force from the variables given: Crank (degrees) measured clockwise from vertical, spindle (degrees) measured anti-clockwise from horizontal, tangent force (N) applied to the pedal surface, normal force (N) applied to the pedal surface and torque (Nm). For example a given reading is

Crank: 10° Spindle: -18.21° Tangent force: 55.96N Normal force: -126.7N Torque: 6.4Nm

Any help that can be provided is greatly appreciated.

The Attempt at a Solution

I have been attempting to use equations with the tangent and normal forces acting as x and y. Then using the spindle angle to try and calculate the resultant force with little success.

Please tell us what the actual problem is ? Forces on a bike pedal is a bit too vague . How about posting a diagram ?

Nidum said:
Please tell us what the actual problem is ? Forces on a bike pedal is a bit too vague . How about posting a diagram ?

This is what I have been given

Part 1

You have been given pedalling force data for 10 cyclists to analyse. Write a Matlab code to calculate the following for each cyclist:

Throughout the pedal stroke (i.e. additional columns of data):

•  Resultant pedal force (F RESULTANT)
•  Force tangential to the crank arm (crank arm length = 170 mm) (i.e. the effective pedal force, F EFFECTIVE)
NOTES:
Each worksheet contains the data for one cyclist and the five columns to data are:

1. CRANK crank angle measured clockwise from top dead centre (i.e. vertical pointing upwards)

2. SPINDLE
pedal spindle angle measured anti-clockwise from horizontal

3.
Ft and Fn
surface
are the forces applied to the pedals tangential and normal to the pedal

4. TORQUE torque applied to turning the crank arm (TCRANK)

david03
I would suggest making your own diagram showing that info if not given one.

Toby said:
pedal spindle angle measured anti-clockwise from horizontal
Based on that, I would guess you are to assume no frictional force between shoe and pedal.

Toby said:
This is what I have been given

Part 1

You have been given pedalling force data for 10 cyclists to analyse. Write a Matlab code to calculate the following for each cyclist:

Throughout the pedal stroke (i.e. additional columns of data):

•  Resultant pedal force (F RESULTANT)
•  Force tangential to the crank arm (crank arm length = 170 mm) (i.e. the effective pedal force, F EFFECTIVE)
NOTES:
Each worksheet contains the data for one cyclist and the five columns to data are:

1. CRANK crank angle measured clockwise from top dead centre (i.e. vertical pointing upwards)

2. SPINDLE
pedal spindle angle measured anti-clockwise from horizontal

3.
Ft and Fn
surface
are the forces applied to the pedals tangential and normal to the pedal

4. TORQUE torque applied to turning the crank arm (TCRANK)

I just got the same problem given now. Have you resolved this?

david03 said:
I just got the same problem given now. Have you resolved this?

topsquark

1. How do I calculate the resultant force for a bike pedal stroke?

To calculate the resultant force for a bike pedal stroke, you need to consider the force applied by the rider on the pedal, the weight of the rider and the bike, and the resistance from the ground. You can use the formula F = ma, where F is the force, m is the mass, and a is the acceleration. First, determine the mass of the rider and the bike. Then, measure the acceleration of the pedal as it moves in a circular motion. Finally, use the formula to calculate the resultant force.

2. What factors affect the resultant force for a bike pedal stroke?

The main factors that affect the resultant force for a bike pedal stroke include the force applied by the rider, the weight of the rider and the bike, the resistance from the ground, and the angle of the pedal. The rider's technique and position on the bike can also have an impact on the resultant force.

3. How does the angle of the pedal affect the resultant force?

The angle of the pedal can affect the resultant force by changing the direction of the force applied by the rider. When the pedal is at a 90-degree angle, the force applied by the rider is straight down and results in maximum power. However, at other angles, the force may be directed more horizontally, resulting in less power.

4. Can we use the same formula to calculate the resultant force for both legs during a bike pedal stroke?

Yes, you can use the same formula to calculate the resultant force for both legs during a bike pedal stroke. However, you will need to consider the force applied by each leg separately and add them together to get the total resultant force.

5. How can I improve my resultant force during a bike pedal stroke?

To improve your resultant force during a bike pedal stroke, you can work on your technique and positioning on the bike. This includes keeping your body aligned and applying consistent and powerful force on the pedals. Additionally, strength training and conditioning exercises can also help improve your resultant force.

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