Student Projects

VG100

Auto Bush-trimming Car

Instructors: Dr. Mian Li, Dr. Irene Wei
Team Members: Longlong Chen, Qian Dong, Wenjun Su, Yingyue Huang, Yujie Guan

Project Video

Team Members

Team Members:

Longlong Chen, Qian Dong, Wenjun Su, Yingyue Huang, Yujie Guan

Instructors:

Dr. Mian Li, Dr. Irene Wei

Project Description

Problem

Trimming bushes is a tough work. It is boring and repetitive job. Also, workers need to bend down, which is tiring. Moreover, when weather is not comfortble, the work is even harder. These difficulties lead to the low efficiency of the work. furthermore, the eveness of the bushes trimmed by the workers is far from satisfactory.

Concept Generation

The aim of our product is to design a robotic car to help trim bushes. Our car can automatically go along the bushes and trim the bushes using a blade. Moreover, people can control the car with the help of an app to let it start or stop and adjust the height of the blade.

Design Description

Our solution is a auto bush-trimming car composed of three parts: auto driving part, bush-trimming part and remote control part. The auto driving part uses ultrasonic sensor to let the car drive along the bush. The bush-trimming part uses a motor to let the blade spin at a high speed to trim the bush. Besides, the height of the blade can be adjusted. The remote control part contains a Bluetooth module to connect the smartphone and the car so that the app can control the car.
Fig. 1 The structure of the car
Fig. 2 The remote control part

Modeling and Analysis

There are three parts in our car: auto driving part, bush-trimming part and remote control part. In the auto driving part, we use L298N to control the motor so that the car can go forward and turn. Besides, the car uses ultrasonic sensor to get the distance from the bush to go along the bush. In the bush-trimming part, we use motor to spin the blade so that the bush can be trimmed. Moreover, we choose Y27-100C, a screw rod plus a stepper motor, to adjust the height of the blade. In the remote control part, we choose HC-05, a Bluetooth mode, to connect the car and the smartphone. And there’s an app to control the move of the car and the height of the blade.
Fig. 3 The phone app

Validation

We did a comparison between human and robotic car about cutting brunches. Brunch is a good choice to simulate bushes. The comparison includes velosity and variance. The velocity of robot is 0.8m/s, and that of people is 0.15m/s. Moreover, the evenness of the brunches trimmed by robot is higher. Finally, we arrive to the conclusion that our robotic car performs better than human beings in both speed and evenness.

Conclusion

Based on daily observation, we design and build our auto bush-trimming car. Not only can it largely decrease the time and energy spent on trimming bushes, but also improve the evenness of the bushes’ heights. As a result, the purchasers, like companies and governments, can cut down the money spent on bush trimming. In the future, our team hope to enable our car to avoid obstacles, such as street light, automatically when trimming bushes on the road. Our car will reduce workers’ workload and add beauty to the natural environment.

Acknowledgement

Dr. Mian Li and Dr. Irene Wei from the UM-SJTU Joint Institute;
Teaching Assistants [Fubo Qi, Hanyang Feng, Sheng Qiao, Xiaoxuan] for VG100 at UM-SJTU Joint Institute.

More project information, please contact: [sarah-dong@sjtu.edu.cn]