Materials and CAD Files

Structural Components

Electronics and Motors

Hardware

Custom Part Files

Tube Materials

Assembly Guides

Custom Part Manufacturing Guide

Full System Assembly

Cart Assembly

Tube Fabrication

Electronics Setup

Electronics Board Setup

Firmware Installation

Wire Management

Full System Test

Kinematics

Calculating Kinematics of a CTR

Implementing Kinematics

Troubleshooting Kinematics

Experiments

Installing Tubes

Homing the Robot

Graph Paper In-Plane Bending Experiment

Out-of-Plane Rotation Experiment

In this page, we will show you how to assemble a full actuation system for a concentric tube robot. Before assembling your system, you will need to have all of the structural components, electronics, hardware, and custom printed or laser-cut parts ready.

Tools and Equipment

You will need the following tools and equipment to assemble your full actuation system:

• 2.5mm hex key
• 3mm hex key
• 4mm hex key
• Pliers, variable size wrench, or wrench for M5 and M4 bolts.
• Drill with hex bits (optional)
• Soldering iron

Instructions

1. Attach linear motion clamps to one end plate. Use two M5 button head screws per linear motion clamp. Add one M5 washer and one M5 nut to each screw.

<aside> 📎 If you are using 1/4” acrylic for your plates, you will need to use two sandwiched plates to create one 1/2” plate. Finger tighten all 4 linear motion clamps to ensure the plates are lined up. Once all screws, washers, and nuts are in place, tighten the screws using a hex wrench and pliers.

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1. Attach linear motion rails and lead screw. Insert linear motion rails into the top three clamps and the lead screw into the clamp along the flat bottom. Insert a lead screw adapter in between the lead screw and the linear motion clamp. This is to protect the threads and ensure the lead screw does not move. Tighten all clamps.

<aside> ⚠️ Make sure to tighten the lead screw clamp such that it cannot rotate within the clamp. If it can rotate, the rotation from the stepper motions will not be completely converted into movement of the cart; it will also move the screw. This can result in inaccurate positions.

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1. Assemble carts. Follow the instructions on the Cart Assembly page, and assemble as many carts as you will need. For each tube of your CTR, you will need one cart to actuate it.

<aside> 📎 Note that half of your carts should be a mirror image of the example cart. The image below shows both the example version of the cart and a mirrored version of the cart. The image at the top of this page shows the mirrored carts in the final assembly.

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1. Manually twist carts onto the lead screw. Using your fingers, turn the lead nut on each cart and manually move them onto the main frame.
2. Attach second end plate. Take the second end plate from step 1, and fasten it to the other end of the linear motion rails.

<aside> 📎 If you are struggling to fit the second end plate onto the rails, you may need to loosen some of the screws holding the clamps to the plate. It is helpful to entirely remove the lead screw linear motion clamp from this plate before inserting it. Push the plate farther onto the linear rails such that the linear rails poke through the clamps by about an inch. Tighten the lead screw clamp around the lead screw, and then move the clamp back to the end plate. Fasten the clamp back to the end plate. Tighten all other clamps.

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1. Apply some of the printer grease to the lead screw. Use a glove or a paper towel to apply the grease directly to the lead screw. Do not use up the entire tube; apply small spots of grease for now. When you start using the robot, you can apply more grease if the carts continue to squeak as they move.

This completes the assembly of the actuation system!