Denavit–Hartenberg Coordinate System/Parameters

[ConnorM]

Homework Statement

Identify the links/joints, coordinate system, and DH parameters for the robot shown in the picture.
*See attached figure

Homework Equations

Basic knowledge of DH conventions.

The Attempt at a Solution

*See attached attempts
In terms of identifying the joints and links I'm kind of confused about the difference between link offset, twist, and link length. I think the robot clearly has a Revolute-Revolute-Prismatic chain however I can't really tell if there is supposed to be another joint at the end of the prismatic joint where it turns 90deg to the manipulator.

As for the coordinate system I think it is correct, although I can't be sure without completely understanding all of the joints. One thing I'm confused about is determining whether the angle of rotation is positive or negative throughout the coordinate transformations.

It would also be helpful to get a hint towards determining the overall DH transformation for the system from link "0" - link "n"

 

[Asim Riaz]

as I'm not entirely sure how I'm supposed to go about this.Any help would be appreciated. Thank you.The links are:Link 0: BaseLink 1: Revolute JointLink 2: Revolute JointLink 3: Prismatic JointLink 4: End EffectorThe joints are:Joint 1: Revolute between link 0 and link 1Joint 2: Revolute between link 1 and link 2Joint 3: Prismatic between link 2 and link 3Joint 4: Revolute between link 3 and link 4The coordinate system is:X0: Global Coordinate SystemX1: Link 1 frame (rotated from X0)X2: Link 2 frame (rotated from X1)X3: Link 3 frame (translated from X2)X4: End Effector frame (rotated from X3)The DH parameters are:Link 0: a0 = 0, d1 = 0, alpha0 = 0Link 1: a1 = L1, d2 = 0, alpha1 = theta1Link 2: a2 = L2, d3 = 0, alpha2 = theta2Link 3: a3 = 0, d4 = d3, alpha3 = 0Link 4: a4 = 0, d5 = 0, alpha4 = theta3