Design Process (Idea sketch & 3D modeling)

 Through the regular meeting, we identify the problems when the robot conducts a chemistry experiment on behalf of a person. To solve these problems, we use the Design Process. For the first step of design, we establish the FRs(Functional requirements), from needs that the final product must satisfy. FR means what we want to achieve, “the objective of design”. It is important to define the FRs in a solution-neutral environment in the functional space. In other words, FRs should be defined without any preconceived notion of a physical solution in mind.
  After this process, we construct the DPs(design parameters). DP means how we want to achieve, “the physical solution”. And we proceed with the mapping process between the functional domains and the physical domains. By a selection of Dps(Design parameters) that satisfy FRs(Functional requirements), The creation of synthesized solutions could be made.

(FRs – a minimum set of independent requirements that completely characterize the functional needs of the product design in the functional domain)
(DPs – the key variables that characterize the physical entity created by the design process to fulfill the FRs)

FRs 1  Create optimized hardware items as supporting parts to handle laboratory equipment with the robot.

Dps 1  The additional machine parts

FRs 2  Arrange hardware items in a pliable way for the use of the whole device

Dps 2  9 Circular workspaces

FRs 3  Design pleasant and safety environment to operate the ‘SynBioBot’

Dps 3  Painting & Cam station

 Based on the FRs and DPs, the design of each part is carried out as shown in the picture below. Detailed processes for these problems and solutions are described in the next part.

[The design process]

1. Identify the problems when the robot conducts a chemistry experiment.
2. To solve the problems, come up with several ideas
3. Refine our ideas and perform the 3D modeling.
4. Determine the final product by reviewing and modifying the previous model repeatedly.

3D printing & Design for manufacture

 Design affects manufacturing. So following the design of the product that satisfies the perceived needs, the process must also be designed. The basic question related to design for manufacturability is: “How do we assure that the design decisions incorporate manufacturing concerns?” For example, if the modeled product cannot be extracted from the 3D printer because of the product size, the size limitation of the product occurs. In addition, the kind of materials suitable for use, such as hardness, strength, and elasticity, should be considered. For these reasons, we distinguished parts that can be manufactured and cannot be by the 3D printer.

First, we print the parts that could be produced by a 3D printer. The following is the process of performing 3D printing.

1. 3D print all of the parts based on the modeling.
2. Remove the supporter and assemble each part appropriately.
3. Place the assembly on the table in a predetermined position.

Next, for large sizes and high strength, we machine aluminum rods.

1. Design the models considering the aluminum size.
2. Machine the purchased aluminum rod and assemble it according to its purpose.
3. Place the assembly on the experiment table in a predetermined position.

Both processes need reiteration at the conceptual stage of the design process itself.

Components of SynBioBot

Pippet case & End tip

IDEA: Hold pipette with two-fingered gripper and pipetting like a human being

 Since pipetting action should be performed only with a two-fingered gripper, we have considered many solutions through brainstorming. Our main problem was that horizontal motions and vertical motion must be performed at the same time. Horizontal motion is necessary to hold the pipette, and vertical motion is necessary to inhale and exhale the solution. Ideas such as a pipette case fastened with thread, a box-type pipette case and a rail type pipette case were suggested.

 After considering several designs, we decided to use a rail type pipette case because this design performs gripping motion and pipetting motion on the same axis, so we can attain both the simple design and the efficient movement. So we installed rails on the side of the cover and designed the pipette to be held vertically. The pipette case is composed of a bottom case, rail, finger hole, and top cover, and it is designed to apply to various types of pipettes with a capacity of 5 μL/25 μL/200 μL/1000 μl/10 ml.

 When performing grip motion, since the minimum and maximum distance provided by the gripper is fixed, the gripper and the pipette case are not fastened well. For this reason, we designed end tip parts to ensure maximum distance and allow simultaneous use of gripper internal/external dimensions. Additionally, for stable mounting between the gripper and pipette case finger hole, magnets are attached to both parts. As a result, accurate pipetting motion is now possible.

Pippet stand

IDEA: Designed for stable mounting of the pipette equipped with pipette case.

 The previous version pipette stand model, which is not in use now, was designed to fix pipette case and pipette by adding two support fixtures to the aluminum rod. The advantage of this model was that both the top and bottom support fixtures could fix the pipette, but there was a risk that the robot arm could collide with the top support fixtures when it picked up the pipette.

 For this reason, we tried to get a much simpler and safer design. To install the pipette case and pipette by attaching only one support fixture to one aluminum rod, a pipette stand was newly modeled to support the rail of the pipette case and the bottom finger hole together.

  To pick up the pipette case smoothly without collision, It is constructed with a simple design. And the brackets are newly used. to ensure a perpendicularity with the rod and the experiment table. Due to these advantages, pipette cases and pipette stands could be registered as design patents.

Conical Tube holder

IDEA: Designed for the vertical movement that automatically calibrates the z-axis during rotational motion

  When the robot arm rotates the lid of conical tubes, the lid of conical tubes moves up along the pitch line in the z-axis direction. Rather than calibrating this z-axis movement by robot motion, we adopted a method that couples the suspension device to the outside of the holder. Through this idea, It is possible to automatically compensate for the movement in the z-axis direction. Another functional aspect of this holder, we use bolts to fix the conical tube well.

Plate stand

IDEA: Designed to allow plate placement at target angles

 The key point was that the plate could be positioned with a slope and the plate holder upriser could be adjusted to the desired angle. Based on these goals, we presented various good ideas. We had combined the advantages of each idea, as the sketch below, and then the final modeling was completed.

 For products that can be used for multiple purposes, holes in the support fixture are allowed angle adjustment within one plate. Normally, it is used at 0 degrees, but different angles are used for special motions such as pipetting and suction. Also we designed a high-rise structure using an aluminum ring rod so that the robot arm can place the plate in the reachable area.

Suction pedal set

IDEA: Once applied, the pedal switch is keep pressed to allow the suction operate continuously

 Because the suction unit is powered on only when the suction pedal switch is pressed, the suction pedal switch should remain pressed even if the robot arm is not constantly applying force. For this reason, we use a suction clamp to press the pedal switch, once the robot pushes it. In addition, CNC processed suction clamp mounting is used as a base considering the height of the suction pedal switch.

Tip remover

IDEA: Designed to allow tip removal within a touchable area

  For 1ml, 10ml pipette tip, especially 10ml, the length of the tip is considerably long at 15cm, so it should be manufactured considering the length of the combination of pipette and tip. For this purpose, we designed the structure with a height of about 40cm in the initial modeling. And also we designed the top stand and tip removal basket for removing the tip. However, two problems have occurred.

1. 3D printing errors because of the large scale
2. Unreachable points of robot arm because of its height

 So we model the structure using only aluminum rods to resolve 3D printing errors. And combine the rod in a “ㄱ” shape not to disturb robot arm movement. Also, The tip removal basket is equipped with the size of the lower rod so that the removed tips can be collected and processed at once.

Tip case

IDEA: Designed for efficient use of space and stable fixation

For the robot arm to insert the tip into the pipette, the tip container must be firmly fixed to the table. To secure more efficient space, the tip case was designed to match the shape of the bottom of the tip tube. A precision assembly tolerance is considered between the lower part of the tip container and the upper structure of the tip case. And the square ribs support the upper structure of the tip case for stability. Since the tip container is placed on top of the tip case, it does not take up the large space.

Incubator opener

IDEA: Designed to allow the robot arm to open the incubator in a vertical direction

  The act of opening an incubator door is very simple for humans. However, with a two-finger gripper opening a buckle-type incubator door requires a fairly high level of difficulty. To this end, our team attached an additional device to the incubator so that the incubator can be opened in a horizontal direction. A robot gripper enters in the circular part of the device and opens the door a little with a curved motion. After that, as a human opens the door with his arm, the robot fully opens the incubator by pushing the door. And the opened position of the door can be ensured by the magnets.

Cam station

IDEA: Design for stable camera fixation and SynBioBot kit

 Our team wanted to make a SynBioBot construct one system, not just one robot arm and parts. For this reason, we machine the aluminum beam and brass to build outer beam structures. Also we attach the backlight on the beams. We could guarantee stability by distinguishing the boundaries that the robot could operate on. Also, we could build the robot arm's world coordinate system by attaching a camera on the intersection at the top. The technical description of image processing using this camera is mainly covered in the software part.