Chapter 4: Building Task-oriented Components

Over the past decade in the FTC robotics competition, object grasping have been a mainstream task and it has evolved significantly, reflecting advancements in technology, engineering, and the overall sophistication of participating teams. One notable trend has been the increasing emphasis on precision and versatility in robotic gripper designs. FTC teams need to explore various mechanisms, from traditional claw-like structures to more complex multi-jointed fingers, in order to effectively grasp and manipulate game elements. The introduction of new materials, such as lightweight alloys and 3D-printed components, has enabled teams to optimize their gripper designs for both strength and agility. Moreover, the integration of sensors and computer vision systems has played a pivotal role in enhancing the grasping capabilities of FTC robots. Teams need to leverage these technologies to implement more sophisticated feedback mechanisms, allowing their robots to adapt to changing conditions and autonomously adjust their grip strategies. In addition to hardware innovations, software advancements have been crucial in enabling robots to perform more complex grasping tasks automatically during the autonomous period of the game. Collaboration and knowledge-sharing within the FTC community have been key drivers of progress, with teams learning from each other's successes and challenges through forums, competitions, and collaborative events. Overall, the past few years have witnessed a remarkable evolution in grasping tasks within the FTC robotics competition, showcasing the creativity and ingenuity of young minds in the field of robotics and engineering.

I’ll share my experience in gripper design for various grasping tasks in the past 3 years, respectively. In the 2021-2022 season, the game came with two different game elements that fall into the freight category to grasp: cargo and boxes (Figure 41). Each type of freight varies in size, shape, and material, which will impact the gripper design.

Figure 42 shows the first version of my gripper design for the FTC 2021-2022 season. I used a motor to extend the gripper and used a servo to perform the grasping action. The advantage of this design is its ease of operation, while the disadvantage is that it took a long time to finish the motor-driven extension of the gripper. Figure 43 shows a working robot with this gripper design, and Figure 44 shows the extended and retracted gripper, respectively. Due to the time consumption of extending and retracting the gripper, I later replaced it with a freight roller (Figure 45), which demonstrated significantly better performance. Also, an additional gripper was added to the side of the robot for long-distance freight grasping, as shown in Figure 46.

The FTC 2022-2023 season featured the task of picking up a cone and putting it into a junction, as shown in Figure 47. An early version of the gripper design is shown in Figure 48. However, it did not work very well. Accordingly, I improved and designed a gripper using two gears and one driving servo as shown in Figure 49. It turned out that this design worked very well. A top-down view of the gripper is shown in Figure 50. A major advantage of this gripper design is that its working zone is quite large so that it is easy for the operator to perform the grasping action without the need to fine-tuning the robot’s location and orientation too much. This large working zone of the gripper also helped the autonomous mode to allow for bigger localization errors.  

In the FTC 2023-2024 season, one of the tasks is to grasp the pixels (Figure 51 (left)) on the ground and deliver them to the backdrop board, as shown in Figure 51 (right). I designed a gripper based on two gears and a servo, as shown in Figure 52. It has been shown to be working very well. There are many other ways of designing grippers for various grasping tasks. My experience is that using gears and servo for grasping is quite an easy and effective solution.

In addition to object grasping, there are also many other tasks specifically designed in different seasons. For instance, in the 2021-2022 season, I used a speed servo with gecko wheels to spin the rubber ducks, as shown in Figure 53. This attachment is used to spin the carousel. Figure 54 shows a freight (either cargo or box) box delivery system by leveraging the cascading kit which can elevate the freight box from the bottom to the top. Figure 55 shows an example of using a servo to drive a TSE (team shipping element) picker.

It should be noted that the entire FTC robot, including all of its attached components, should be fitted into a dimension of 18 inch * 18 inch * 18 inch, as shown in Figure 56.