Robot Arm

Research of the kinematic parameters of the robot arm

At this stage you will gain an understanding of the principles of the robot`s movement.

Use control sliders to change the robot`s position and move the gripper to the aimed object.

Order of the experiment

• Study the composition and technical characteristics of the laboratory setup, as well as the kinematic structure of the robot, following the guidelines:
• Access the laboratory experiment page (Laboratory experiment #1) and enter the unique access code on the "Dashboard" control console, provided by the instructor (Session Code), by clicking the "Request Control" and "Apply" buttons;
• Enter student`s personal data on the "Home" tab. After this step, the participant is granted the right to control the robot (experiment).
• Activate the robot's joint servomotors by using the sliders in the "Run Experiment" control window. Observe through the webcam as the robot gradually changes its position in space to grasp the object in front of it.
• After successfully grasping the object, record the grip manipulator's position data (Coordinates of the grip [x, y, z]) manually or use the button to transfer the values automatically. This information will be automatically transferred to the corresponding fields for the report.
• Capture a screenshot of the robot's position using the built-in "Take a snapshot" button.
• Answer the control questions on the laboratory experiment page.
• Proceed to the next experiment.

Run the experiment

Coordinates of the grip [\(x\), \(y\), \(z\)]
\(O_6\) Take a snapshot

What can be observed in the Current/Time diagram during operation of each separate servo drive?

Q1

The Denavit-Hartenberg parameters in robotics

In this experiment the main goal is study and use of the Denavit-Hartenberg parameters

Quick memo on the formulas from the methodical guidelines:

\(\begin{bmatrix} x_{06_{i-1}} \\ y_{06_{i-1}} \\ z_{06_{i-1}} \\ 1 \end{bmatrix}=M_i\times\begin{bmatrix} x_{06_{i}} \\ y_{06_{i}} \\ z_{06_{i}} \\ 1 \end{bmatrix}\)

\(M_i=\begin{bmatrix}\cos\theta_i & -\sin\theta_i\cos\alpha_i & \sin\theta_i\sin\alpha_i & r_i\cos\theta_i \\\sin\theta_i & \cos\theta_i\cos\alpha_i & -\cos\theta_i\sin\alpha_i & r_i\sin\theta_i \\0 & \sin\alpha_i & \cos\alpha_i & d_i \\0& 0 & 0 & 1 \end{bmatrix}\)

Order of the experiment

• Study the composition and technical characteristics of the laboratory setup, as well as the kinematic structure of the robot, following the guidelines:
• Go to the laboratory experiment page (Laboratory experiment #2) and enter the unique access code on the "Dashboard" experiment control console, which was provided by the teacher (Session Code), by clicking the "Request Control" button and the "Apply" button.
• Enter student`s personal data on the "Home" tab. After this step, the participant is granted the right to control the robot (experiment).
• Set the position of the robot in the space of the working area by entering arbitrary values of the angles, using the fields for entering the values of the "Angles, deg" window, taking into account the specified limitations of the working angles of the robot in the "Limit range, deg" field. To access the control window, press the "Run Experiment" switch and update the position of the robot, use button to set previous angles as a setpoint, press the "Update setpoint" button.
• Using the button in the "Coordinates of the grip [x, y, z]" field, automatically transfer the robot's grip coordinates to the \(real O_6\) field from the "Coordinates of the grip" window.
• Get the coordinates of the robot joints using the "Run Experiment" panel. Calculate the transfer matrices according to the formulas given in the methodological instructions, using the values of the obtained angles.
• Calculate the coordinates of the joints of the manipulator in the coordinate system relative to the point \(O_6\)
• Manually enter the calculated grip coordinates to the \(math O_6\) field from the "Coordinates of the grip" window.
• Take a screenshot of the robot's position using the "Take a snapshot" button.
• Answer the control questions on the laboratory experiment page.
• Proceed to the next experiment.

Run the experiment

Angles, deg	Limit range, deg	Coordinates of the grip [\(x\), \(y\), \(z\)]
\(\theta_1\) \(\theta_2\) \(\theta_3\) \(\theta_4\) \(\theta_5\) \(\theta_6\) \(\theta_7\)		\(real O_6\) \(math O_6\) Take a snapshot

What are the steps of the Denavit-Hartenberg method?

Q2

Use of trigonometry in robotics

At this stage you will learn to use position of the robot to get angular information

Quick memo on the formulas from the methodical guidelines:

\(\theta_2\in x\leq \angle90\) \(\theta_2=\beta\)	\(\theta_2\in x > \angle90\) \(\theta_2=\pi-\beta\)
\(\theta_3\in x\leq \angle90\) \(\theta_3=\gamma-\frac{\pi}{2}\)	\(\theta_3\in x> \angle90\) \(\theta_3=\frac{3\pi}{2}-\gamma\)
\(\theta_5\in x\leq \angle40\) \(\theta_5=\delta_2-\frac{\pi}{2}\)	\(\theta_5\in x> \angle40\) \(\theta_5=\frac{3\pi}{2}-\delta_1-\delta_2\)

Order of the experiment

• Study the composition and technical characteristics of the laboratory setup, as well as the kinematic structure of the robot, following the guidelines:
• Go to the laboratory experiment page (Laboratory experiment #3) and enter the unique access code on the "Dashboard" experiment control console, which was provided by the teacher (Session Code), by clicking the "Request Control" button and the "Apply" button.
• Enter student`s personal data on the "Home" tab. After this step, the participant is granted the right to control the robot (experiment).
• Using the object management sliders, on the “Run Experiment", set the free position of the work in the space of the working area, controlling the process through a webcam. At the same time, you should take into account the conditions that links 4 and 6 must be in a position of 90 degrees.
• Take a screenshot of the received manipulator configuration using the "Take a snapshot" button.
• Transfer the coordinates of the points from the "Run Experiment" window to the "Link coordinates [x, y, z]" response field by clicking the button to fix the instantaneous values of the coordinates.
• Calculate the angles of movement of the corresponding links of the robot using methodical instructions.
• Enter the obtained results in the answer field "Angles,deg".
• Answer the control questions on the laboratory experiment page.
• Go to the "Save work" page and generate an automatic report. Then save the report to your device.

Run the experiment

Coordinates of the links [\(x\), \(y\), \(z\)]	Angles, deg
\(O_1\)	\(\theta_1\)
\(O_2\)	\(\theta_2\)
\(O_3\)	\(\theta_3\)
\(O_4\)	\(\theta_4\)
\(O_5\)	\(\theta_5\)
\(O_6\)	\(\theta_6\)

Take a snapshot

What theorem underlies all the calculations?

Q3

Save your work