Model of a rotary joint driven by a linear motor

Introduction

This post explain and describe the model of a rotary joint actuated by a linear motor, or an air cylinder. The goal of this model is:

to compute the angle of the rotary joint according to the actuator length ;
to compute the torque on the joint according to the actuator force.

Here are our hypotheses:

The length of the motor \( | \overrightarrow{AB} | \) is known
The offset of the motor \( | \overrightarrow{BC} | \) is known and fixed
The length of the lever arm \( | \overrightarrow{OA} | \) is known and constant
The length of the frame \( | \overrightarrow{OC} | \) is known and constant
The triangle \( ABC \) is rectangle in B
The motor produces a force \( F \)

This article is splitted in tour parts:

See also

Last update : 10/08/2022