We are team Clovers from Joint Institute, Shanghai Jiao Tong University (SJTU). Joint Institute, an international institute established by the University of Michigan (UM) and SJTU, is located on the SJTU’s Minhang campus. It is a famous international program in Shanghai aiming to nurture first-class leaders.
The course VG100, Intro to Engineering, aims to teach students how to solve a problem in an engineer’s way. For project 1, Naval Battle, we are required to build a robot to move balls from our field to the opposite field to get scores. In three minutes, the team which gets a higher score wins.
1. The field is 2000mm*1500mm large and a barrier which is 50mm above the ground, 70mm high and 18mm wide divides the field into two equivalent parts. The surrounded walls are 120mm high and 18mm wide.
2. Each part of the field will have 12 balls placed in the designed positions.
3. Specifications of the balls:
(1) The small ball has a diameter of 40mm and weighs 40g.
(2) The large ball has a diameter of 70mm and weighs 170g.
4. Scoring rules:
(1) A total 24 pts is distributed in 8 small balls (1 pt/each) and 4 large balls (4 pts/each).
(2) A punishing reduction of 2/5 pts is given for every small/large ball that is hit out of the field during the game.
(3) The score will be determined by the final position of the balls.
5. Competition process:
(1) In the first round of the game, each individual team will have 3 minutes to move 12 balls. The top eight teams can get into the competition round.
(2) In the second round, teams are coupled to compete. Moving both the balls of yours and your enemy’s is allowed. The team which gets a higher score in 3 minutes wins.
(3) It is OK to take the robot out of the field to fix it, but the time will not stop and the robot must be placed in the initial place after repair.
1. Robot’s dimension limit: 350mm*350mm*200mm.
2. In terms of motor, only the two motors provided by the lab are allowed.
3. There is no strict limit on voltage, weight.
4. There is no specific limit on function as long as the robot can move balls to the opposite field.
We succeeded in moving all the balls to the opposite field which means our score is 24 and the place is final eight. The following link is to the video of our performance on the game day.
Step 1: DESIGNING CONCEPT
The concept diagram of our design is shown above. The core of the robot is an Arduino Uno R3 board which controls all the modules on the robot. With a PS2 module, a motor driving board and a servo are controlled remotely to run two rear-wheels and the lifting device respectively.
The lifting device is installed in the pathway in the front of the robot. We can control the robot to press large balls against the barrier in the middle and get the ball into the lift. Then we lift the device through a servo. When the lifting device is lifted higher than the barrier, the large ball will drop to the opposite field itself. We also stick several boards around the lifting device in case the large ball gets out of the lift. As for small balls, we push them forward with the blocking boards.
Step 2: CIRCUIT DIAGRAM
Red wires show 11.1V of input or output.
Green wires show the voltage of 3.3V and 5V.
Wires of other bright colors are the signal wires.
Black wires show the ground.
Motors are driven by L298N and powered by 11.1V battery.
Servo motor is powered by 3.7V battery.
PS2 receptor is powered by Arduino.
Since all the components are controlled by Arduino, they need to share the same ground.
Step 3: MATERIALS LIST
- L-shaped connector*2
- Hexagonal brass metal pillar
- M4 10mm screw*4
- M4 7mm screw*2
- Acrylic board
- Wooden board
- Plastic track
- Cotton thread
- Hot glue
- Carve knife
- Sponge rubber
- Electric tape
- Electric drill
- Soldering gun
Step 4: BUIDING THE BASE OF THE ROBOT
（a）Prepare an acrylic board (3mm) and cut it into designed size 300*180*3（mm）.
（b）Saw a 90*45*3（mm）area from the middle part of the right side.
（c）Mark the location of holes and drill them. (This will be the place to install the rear-wheals on the base. )
Step 5: ASSEMBLING THE WHEELS
（a）Solder one DuPont line with the positive pole of the gear motor and the other line with the negative pole.
（b）Connect the rear-wheel and the gear motor with an L-shaped connector and a hexagon copper post. Then, fix the connection by adding a M4 screw with 7 centimeters in length.
（c）Link the L-shaped connector and the acrylic base by a 10-centimeter-long M4 screw.
（d）Use hot glue to fix the two rollers on the front part of the acrylic board.
Step 6: CREATING THE LIFTING DEVICE#1
（a）Cut two parts from a 4mm wood board as designed and make a card slot on one of them so that the other one can insert vertically.
（b）Make two wood L-shaped components and fix them on both sides of the horizontal board.
（c）Strengthen all the connection parts with hot glue.
Step 7: CREATING THE LIFTING DEVICE#2
(a) Drill two small holes on each part by tweezers. Put one end of a plastic wire through a hole in the vertical part and then through the corresponding hole in the horizontal part.
(b) Reel this end to the back of the vertical part where it meets the other end. Stick the two ends together on the back.
(c) Use a burin to change the edge of the two sides of the vertical board which are 4mm in thickness and 5mm in width into 1 millimeter’s feather edge.
(d) Saw a 18-centimeter-long track and stick it in the center of the vertical board’s back.
Step 8: PROCESSING THE TRACK AND ASSEMBLING THE LIFTING DEVICE
（a）Cut two 18 cm plastic tracks and rub the extra part off so as to let the vertical board get through smoothly.
（b）Fix the track on the acrylic base vertically with hot glue.
（c）Cut several wooden sticks as designed and fix them on the track in order to ensure that the track will not waggle in any direction.
（d）Place the lifting device on the track.
Step 9: MAKING a BOX TO PROP UP THE SERVO
（a）Cut four parts (100*24mm *2 & 100*40mm *2) from the 2mm acrylic board.
（b）Glue the four parts to make a box in dimension of 100*24*20mm.
（c）Cut a 29*20*2mm wood and fix it at the top part of the box.
（d）Fix the box vertically on the base.
Step 10: INSTALLING OTHER COMPONENTS OF THE ROBOT
（a）Fix the arduino board, L298 driver module, 7.4V battery, 11.1V battery, PS2 receiving module and bread board on the base. Then, fix the servo on the box and get the pinion stuck between the servo and the rack.
（b）Link the circuit by DuPont lines according to the designed circuit diagram.
Step 11: MAKING THE CEILING OF THE ROBOT
（a）Cut an acrylic board (180*210*2mm) and twelve thin planks (10*130*4 mm)
（b）Divide 12 planks into 4 equivalent groups. For every group, stick three thin planks together and glue the one side of the processed four thick planks on the corners of the ceiling and the other side with the base.
Step 12: TROUBLESHOOTING
（a）Since the ping-pong balls may roll under the base of the robot, stick three wood boards on both sides and the back.
（b）To make it easier for the robot to capture a wooden ball, use a burin to create a slope as the transition part.
（c）Due to too much trials, some components may break down. Prepare some spare materials.