Roboter aus dem Baukasten (3D)
About this app
Drei Roboter aus dem Konstruktionsbaukasten nach den Computing-Kästen von 1985, aus Originalteilen: ein Drehtisch mit Lichtschranke und Impulszählung, ein Plotter mit zwei Schrittmotoren, der auf Papier zeichnet, und ein Knickarm mit vier Motoren, der Bausteine umsetzt. Gesteuert über ein Interface mit Ausgängen, Eingängen und Signalverlauf, mit Referenzfahrt, inverser Kinematik und Teach-In.
With explain mode: an AI tutor walks you through the app, points out what matters in the scene and answers your questions.
The basics
A motor does not know where it is. Robots therefore need feedback: a DC motor gets a light barrier counting lines on a disc, a stepper motor turns by a fixed angle per current change and is counted. Only a homing run to a limit switch sets the zero point. After that every counter value means a position. With an articulated arm, calculation is added: a target point gives joint angles, and those give motor pulses (inverse kinematics).
What you see
Three robots from a construction kit, based on the computing kits of 1985 and built only from original parts. A turntable turns through a worm and slewing ring, and a drum wheel with 32 lines runs through a fork light barrier. A plotter moves bridge and pen on spindles with two stepper motors and draws on paper. A robot arm with four motors, spindle drives and a gripper moves blocks. An interface panel shows outputs, switches and the signal trace in slow motion.
Try it yourself
Start the homing run on the turntable and drive to the stations. The counter shows that the motor overruns by a few pulses until you switch on the compensation. Let the plotter draw the house in one line or draw yourself with your finger. On the robot arm, tap a point on the base plate and read the calculation from target to pulses, or teach it a movement with teach-in.
Frequently asked questions
- What is a homing run?
- After power-on, a controller with pulse counters does not know where an axis is. In the homing run the axis moves slowly to a limit switch, where the counter is set to zero. From then on every counter value corresponds to a fixed position.
- How do stepper motors and DC motors differ for positioning?
- A DC motor turns as long as current flows and overruns after switching off; a sensor such as a light barrier with a line disc measures its position. A stepper motor turns by a fixed angle with every current change, for example 7.5°. If the controller counts the steps it knows the position without a sensor, as long as no step is lost.
- What does inverse kinematics mean?
- Forward kinematics computes where a robot's hand is from its joint angles. Inverse kinematics works the other way: the desired target point gives the rotation and joint angles. For an arm with two links this uses the law of cosines; then the angles are converted into motor pulses.
- What can I do with the robots in the app?
- Drive all three robots by hand and start a homing run. Send the turntable to stations and measure the overrun, draw motifs or your own lines with the plotter, and use the robot arm to move blocks, tap target points and record movements with teach-in.
Subject: Engineering mechanics
More from Engineering mechanics
- Bending stress & moment of inertia
- Düsenjet bis v_max (3D)
- Energy & oscillation
- Truss analysis (method of joints)
- Equilibrium & support reactions
- Kinematics
- Kinetics & Newton's second law
- Forces & vector addition
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