How to calculate resultant force for a bike pedal stroke

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Homework Help Overview

The discussion revolves around calculating the resultant pedal force for a bike pedal stroke, involving various angles and forces acting on the pedal. The original poster provides specific measurements and seeks assistance in determining the resultant force using these variables.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the need for clarity regarding the problem, suggesting that the original description may be too vague. Some participants recommend providing a diagram to better illustrate the forces involved.
  • There are attempts to use equations involving tangent and normal forces, but the original poster expresses difficulty in achieving a successful calculation.
  • One participant suggests assuming no frictional force between the shoe and pedal, indicating a potential assumption that may need to be addressed.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem and questioning the clarity of the information provided. Some guidance has been offered regarding the need for diagrams and assumptions, but no consensus or resolution has been reached.

Contextual Notes

Participants note that the problem involves analyzing pedal force data for multiple cyclists and writing a Matlab code to calculate resultant forces throughout the pedal stroke. There is an emphasis on the need for clarity in the problem setup and the potential for assumptions that may affect the calculations.

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.

Homework Equations

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.
 
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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)
 
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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?
The thread is five years old. Please post your diagram for the question as you understand it… preferably as a new thread.
 
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