Design
Our robotic platform is composed of many modules, each with their own specifications, concept and functionalities. Each module is designed to be independent so they can operated alone or jointly with other modules. The teamwork between every module is managed by the Main Administrator that communicates with all of them, and controls them via a bus CAN and custom controller boards, named BananaBoard. In its entirety, the project has seven distinct modules: The platform, the tool holder, the gripper, the centrifuge, the magneto caloric module for 96-well plate, the magneto caloric module for 1.5mL tube and the turbido agitator caloric module for glass tube. Additionaly, most of these module are controlled by our custom controller board. The global architecture of the robotic platform is as follows:
Biobot Project Global Architecture
In this page you will learn all there is to know about each module, whether it is for the electrical, mechanical or software design. Scroll down or choose one module to learn about it.
Modules
Platform
Description
The physical platform consists of everything related to the structure on which the movements take place. It is equipped with a motor and traction mechanism for the XY plane of movement, as well as indicators to locate the home position of each axis. Atop the structure is the travelling bridge and trolley, with the tool holder. The movements and limit detection of the platform are supervised by a bought controller board: the SmoothieBoard. The robot does smooth and precise movements and gives feedback on its position on demand. Our first version of the platform was the robot bought from OpenTrons. Since the beginning of the project, we build a completely new platform, which is bigger and stronger. The redesigned platform was quadrupled in size, the motors was changed for a stronger and faster model, and the original work area with rails was changed for a pegboard for easier placement of the modules.
Biobot Project Physical Platform (La changer pour une récente avec les modifications)
The frame is made up of aluminium extrusions. Aluminium extrusions were selected due to their lightness, rather low cost and simplicity to sterilize, which is a great advantage for a platform used in a biology lab. When designing the platform, we sometimes created a first version using a 3D printer to validate our concept. After validation, most of those parts were replaced by a machined metal version.
Movements of the different axes are ensured by stepper motors to perform translations of the travelling bridge and of the trolley. For movements relative to the XY plane, two NEMA 23 stepper motors, model 17HS3001-20B, were used. They offer fast speeds, while still being precise as to 200 microns, which is useful to move the tools to a precise position without slowing down the whole process. These motors are attached to an endless screw which makes the assembly moves as it spins. The are also used because they are durable and reliable. Those two assets are significant since repetitive movements occur in the XY plane, which consequently deals more wear and tear.
Specifications
Mechanical
Specification |
Value |
Frame material |
Aluminium extrusions |
Dimensions |
160 cm x 120 cm x 130 cm |
Motion mean |
Stepper motors coupled with endless screws |
X axis movement precision |
0.25 mm |
X axis movement speed |
50 mm/s |
Y axis movement precision |
0.25 mm |
Y axis movement speed |
50 mm/s |
Electrical
Specification |
Value |
Motors' input voltage |
24V |
Software
Specification |
Value |
Language |
C++ |
Parts list
...
Assembly
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Tool Holder
Description
One of the main scope of the platform is to perform pipetting operations using different type of pipettes, namely, single-channel and multi-channel pipette as needed by the lab protocol. To hold and use them, a custom tool holder was designed and built. The holder is fixed on the trolley which is fixed on the travelling bridge. The tool holder have three independent C-Beam by OpenBuilds to perform movement along the vertical axis. The two first C-Beams are used for pipettes. The third one is used for the gripper. Pipettes' C-Beam are equipped with a pipette holder, made of actuators to press the piston and the tip release push-button.
Specifications
Mechanical
Specification |
Value |
Frame material |
Aluminium extrusions |
Dimensions |
X cm x X cm x X cm |
Motion mean |
Stepper motors coupled with endless screws |
Z axis movement precision |
0.25mm |
Z axis movement speed |
50mm/s |
Electrical
Specification |
Value |
Motors' input voltage |
24V |
Software
Specification |
Value |
Language |
C++ |
Parts list
- 3x C-Beam Linear Rail, 500mm
- 3x NEMA 23 Stepper Motor, Model: Motech Motor, MT-2303Hs280AW-0B, 1.8°/Step
- 3x C shaped rails, 500mm
- 3x Endless screw, 500mm
- 2x XX Motor pour le pipettage
Assembly
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Gripper
Description
The finger-like gripper is design to allow the handling of lab-ware around the work area. It can moves tubes, micro-plate and different type of boxes around as needed. The gripper is fixed to one of the three z-axis of the tool holder . It can therefore be used independently of the other tools on the holder. The gripper is first composed of a Dual Gripper Kit from Crust Crawler Robotics. This kit uses two Trossen Robotics' Dynamixel AX-12A servomotors for the finger-like motion. We then added a third AX-12A servo to give the gripper wrist-like capabilities, adding flexion and extension movement. Lastly, a MX-12W servo was also added so the gripper can rotate around a vertical axis on 360°.
This gripper kit was chosen because it uses Trossen Robotics' Dynamixel servomotors. Those servos are easy to control and their precision in movement allowed us to fall within the specification we needed for our gripper. They offer various options to monitor and use different operating values of the servo even during live operation allowing us to use them at our will to control the gripping function of our platform. The most useful Dynamxiel's control function is the torque limit that we can set to a custom value corresponding to the object we desire to grip. Also, the MX-12W was chosen for the gripper rotation because the angle of the servo can be monitored over 360°, unlike AX-12A Dynamixel which can only be monitored from -150° to 150°. The servos assembly gives the gripper the ability to take narrow as well as wider objects, and it can grip them from top or from the side. It can also rotate on 360°. The gripper is controlled by a dedicated BananaBoard.
Specifications
Mechanical
Specification |
Value |
Dimensions |
258 mm x 75 mm x 97 cm |
Motors |
Robotis' Dynamixel AX and MX servomotors |
Fingertip precision |
0.7 mm |
Fingertip speed |
from 0 to 680 mm/s |
Fingertip torque |
from 0 to 1.5 N*m |
Rotation precision |
0.088° |
Rotation speed |
from 0 to 470 rpm |
Electrical
Specification |
Value |
Servos' input voltage |
12V |
Software
Specification |
Value |
Language |
C++ |
Parts list
- 3x Dynamixel AX-12A by Trossen Robotics
- 1x Dynamixel MX-12W by Trossen Robotics
- 1x CrustCrawler AX Dual Robotic Gripper Hardware Kit
- 2x Bioloid F2 Frame
- 3x Bioloid F3 Frame
- 3x 3-Pins Dynamixel Communication Cable
- Bolts and nuts
Assembly
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Centrifuge
Description
Centrifugation operations are often required for protocols in cellular biology lab. Our client therefore asked us to design an automated centrifuge that can be operated with the platform and the gripper.
The centrifuge is able to fit up to eight 1.5mL tubes and up to four 5mL tubes. The rotating plate, which hold the tubes, is fabricated with polyoxymethylene, a lightweight and strong thermoplastic. It is coupled on a Quanum MT series 2208 brush-less DC motor. Such motors offer higher rotation speed and compact size, two characteristics profitable for the whole design. Tube slots allow tube to be vertical when resting, to ease manipulation with the gripper, and force tube to tilt to a 45° angle during centrifugation. To detect high vibrations, a warning of potential problems during run-time, an accelerometer is added to the module. The centrifuge is equipped with an automated lid which is secured by a lock mechanism during running time. Because the lid only opens over one tube slot, we need to rotate the plate from slot to slot when the centrifuge is being loaded by the gripper. To do so, a magnetic sensor is positioned on the axis of rotation so the absolute angular position is known. That way, it is possible to rotate the plate to place a tube slot under the opening in the lid so the gripper can load and unload tubes. And of course, the whole centrifuge case is built with a sturdy construction, using material such as X and Y to prevent any external damage should there be any internal problems. The centrifuge is controlled by a dedicated BananaBoard.
Specifications
Mechanical
Specification |
Value |
Dimensions (Length x Width x Heigth) |
À valider Xmm x Ymm x Ymm |
Rotation Speed |
X rpm |
G Force applied |
18000 G |
Tube capacity |
8x 1.5mL tubes and 4x 5mL tubes |
Electrical
Specification |
Value |
Servos' input voltage |
12V |
Software
Specification |
Value |
Language |
C++ |
Parts list
...
Assembly
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Magneto Caloric 96 (MC96)
Description
MC96 3D Plan
The first module is called Magneto Caloric 96 (MC96) because it has to manage magnetism and temperature cycling (caloric) of a 96-well plate. The main use of the MC96 is to apply a specific temperature on different liquids (e.g. cell cultures) in the context of biological research.
The module has the possibility to concentrate particles in these solutions by applying an electromagnetic field that will bring particles on the wall of the well. This is explained by the magnetic attraction of microscopic magnetic beads to which particles are agglomerated. The beads are to be introduced into the well during the procedure and this can also be automated.
To apply the electromagnetic field, neodymium magnets are moved to the side of the wells. To do so, the magnets are assembled in a frame that is moved by a linear actuator. So, when the actuator raises the frame, the magnets are moved near the wells and the beads are brought on the well’s wall.
To implement thermal cycling, a Peltier element is used because it can heat or cool the 96-well plate depending on the current’s direction. A heat sink is stick to the other side of the Peltier element to eliminate the heat produced by the Peltier element. The fan is used to create a forced convection thus, increasing the efficiency of the heat sink.
Specifications
These characteristics are the specifications required by the client or part’s characteristics because no prototype has been built yet.
Thermal
Specification |
Value |
Range |
4 to 80°C |
Precision |
±1.5°C |
Heating speed |
0.5-1°C/s |
Cooling speed |
0.5-1°C/s |
Mechanical
Specification |
Value |
Material |
96-well mold : Aluminium Frames and Module base : Plastic |
Dimensions |
Width x Length x Heigth cm |
Linear actuator speed |
12mm/s |
Linear actuator stroke |
2cm |
Electrical
Specification |
Value |
Input voltage |
24V |
Maximal power consumption |
≈800 Watts |
Software
Specification |
Value |
Language |
C++ |
Parts list
...
Assembly
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Magneto Caloric 1.5 (MC1.5)
Description
MC1.5 3D Plan
The second module is called Magneto Caloric 1.5 (MC1.5) and has the same functionalities as the MC96, but for tubes containing an amount of liquid as high as 1.5mL, which is more than the capacity of a MC96 well. The MC1.5 is composed of 2 independent sub-modules. So, each sub-module could have its own sequence.
Specifications
These characteristics are the specifications required by the client or parts’ characteristics because no prototype have not been completed yet.
Thermal
Specification |
Value |
Range |
Achieved 4 to 80°C |
Precision |
Achieved ±1.5°C |
Heating speed |
Achieved 1°C/s |
Cooling speed |
Achieved 0.5°C/s |
Mechanical
Specification |
Value |
Material |
1.5ml test tube mold : Aluminium Frames and Module base : Plastic |
Demensions |
Width x Length x Heigth cm |
Linear actuator speed |
12mm/s |
Linear actuator stroke |
2cm |
Electrical
Specification |
Value |
Input voltage |
24V |
Maximal power consumption |
≈400 Watts |
Software
Specification |
Value |
Language |
C++ |
Parts list
...
Assembly
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Turbido Agitator Caloric (TAC)
Description
TAC 3D Plan
The main function of this module is to grow cell culture in a 25mm test tube. To do so, the module must regulate the tube temperature, be able to agitate the liquid and to measure the amount of cells in the culture. The TAC module enables the automation of repetitive steps that are performed on a daily basis in laboratories around the world. It can be reprogrammed to meet specifications of different protocols for molecular biology or microbiology experiments.
One possible application of the TAC module would be the insertion of DNA into a microorganism. This manipulation requires the growth of the microorganism at the optimal temperature until a specific optical density is reached. This is required for the observed colony to enter its stationary phase as we can observe in the following Figure.
Cell density of a culture vs time
Once the optical density has been reached, the cells have to be washed a couple times to eliminate the residual growing media. Afterwards, the DNA is added to the mix and the cells are perforated to allow its transfer. This stressful operation kills most of them. Therefore, we have to replicate them quickly in a proper medium and at the right temperature.
To regulate the temperature between 0 and 37°C, a Peltier element is used because it can heat or cool the tube depending on the current’s direction. An heat sink is stick to the other side of the Peltier element to eliminate the heat produced by the Peltier element. The fan is used to create a forced convection thus, increasing the efficiency of the heat sink.
To agitate the liquid, the same principle as a magnetic stirrer is used. First, a magnetic stirrer bar must be inserted into the test tube. Then, a magnet stuck on a DC motor attracted the magnetic stirrer bar. So, when the DC motor rotates the magnetic stirrer bar inside the test tube rotates at the same speed and thus, agitating the liquid.
To measure the amount of cells in the culture, a system has previously been developed by the lab of professor Rodrigue. This system used the transmittance of the liquid to measure the amount of cells in a 25mm test tube. To measure it, a LED (light-emitting diode) is placed on one side of the test tube and a photodiode is placed on the other side. The LED blinks and this blink is received on the photodiode, generating a square signal as shown in the folowing Figure.
![](https://static.igem.org/mediawiki/2015/a/ae/Sherbrooke_TAC_Turbidity_Input_Signal.png)
Photodiode signal voltage vs time
The amplitude difference between the signal high and the signal low increase as the transmittance increased and decreased as the transmittance decreased. A calibration graph has been calculated and is shown in the folowing Figure.
![](https://static.igem.org/mediawiki/2015/4/47/Sherbrooke_Optical_density_vs_Amplitude_difference.png)
Optical density vs Amplitude difference
Specifications
Thermal
Specification |
Value |
Range |
0 to 37°C |
Precision |
±1.5°C |
Heating speed |
Achieved 1.2°C/s |
Cooling speed |
Achieved 0.3°C/s if tube temperature above room temperature Achieved 0.21°C/s if tube temperature below room temperature |
Mechanical
Specification |
Value |
Material |
25mm test tube mold : Aluminium Frames and Module base : Plastic |
Demensions |
Width x Length x Heigth cm |
DC motor speed |
60 to 600 rpm |
Electrical
Specification |
Value |
Input voltage |
24V |
Maximal power consumption |
≈400 Watts |
Turbidity measurement precision |
±5% from a reference turbidimeter |
Software
Specification |
Value |
Language |
C++ |
Parts list
...
Assembly
...
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BananaBoard
Description
With so many different independent modules, it would have been a real struggle to design a Printed Circuit Board (PCB) for each of them. Yet, when you compare modules to each other, you can notice that there is similarities between them. We therefore decided to design a single PCB (that we named BananaBoard)that has all the electrical and software capabilities to supply every modules individually. Yet, the PCB is still functional even if some component are not soldored on it. For example, the BananaBoard has a 24V output connectors. The gripper doesn't need this electrical supply but the MC1.5 and the TAC need it. So the component for this output will not be soldered on the PCB for the gripper, but they will be for the MC1.5 and the TAC's PCB. This allowed us to save design time and reduce complexity during the PCB assembly and debugging.
Specifications
Mechanical
Specification |
Value |
Dimensions (with all component soldered) |
107.9 mm x 80.4 mm x 35.8 mm |
Electrical
Specification |
Value |
Input voltage |
24V |
Output voltages |
12-24V / 60A: Half H-Bridges and Stepper Motors
5V / 1A: Logic Circuit, LED, Sensors
3.3V / 100mA: Accelerometer |
Microcontrôleur |
Cypress' PSoC5 CYC5868AXI-LP034 |
Other components |
- 8x Half H-Bridges
- CAN, SPI and UART communications capabilities
- 2x Stepper motors control modules
- Many various digital and analogue inputs and outputs
|
Software
Specification |
Value |
Language |
C++ |
Parts list
...
Assembly
...
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Controller
Description
...
Specifications
...
Parts list
...
Assembly
...
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