Page 200 - Robot Design Handbook ROBOCON Malaysia 2019

2.0 DETAILED DESIGN

2.2 Mechanical Design

For the MR1, a four-point omni navigation base is chosen because of the stability

and omni-directional movement is easier for passing through the Forest. Brushed motors
are used for the four-point omni robot. Pneumatic cylinder is used to grip the Shagai. Power

window motors are used to rotate the grippers of the Shagai onto the throwing platform.

Extension is used for throwing the Shagai to reduce the distance between the throwing
position and the Landing Zone, so that the accuracy can be increased. The extension and the

throwing of the Shagai is actuated by pneumatic cylinders. The Gerege is held above the

robot using a servo. When the servo rotates, it will release the Gerege from the high position
to the power position. The robot weights 32.4 kg with the dimension of 0.65 m x 1.4 m x
1.46 m.

For the MR2, eight power window motors are used to actuate the legs. The force of

the motors is transferred to the legs using gears. The gears on the robots are printed by using
3D printer. Rotary encoders are used to measure the movement of the legs. The arm for the

Gerege is held by using a hook, raised by using a spring and a servo. When the servo rotates,
it will release the hook and the spring will contract to lift the Gerege up. The robot has two

degrees of freedom. The robot weights 15.7 kg with the dimension of 0.95 m x 0.62 m x

0.64 m.

2.2 Electronic Design

Figure 1 shows the distribution of sensors and the architecture of the processing units

within the MR1 and the MR2 robots, respectively.

For the MR1, we used STM32F407VG [5] as main processor in our main-board and

robot navigation system. H-bridge power distribution module is connected to the main-
board in order to control the valve through the valve driver, servo, LED indicators and

motors for rotating part through motor drivers. For navigation, the motors are controlled by

robot navigation system through motor drivers. Motor driver is equipped with an emergency
button to enable power cut-off to the navigation when the emergency button is pressed.

Besides, the mode selector is used for mode switching in our main-board. Several
sensors such as analog sensors, laser sensors, limit switches, encoders, inertial measurement

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