Page 154 - Robot Design Handbook ROBOCON Malaysia 2019

mm x 151 mm including the shaft to provide rotational motion to the wheel shaft, which

will move the robot.

Figure 9: Mecanum wheel

2.1.3 Walking Mechanism for the MR2

The MR2 is a fully automatic robot which moves on four legs. Both left and right

legs of the robot are connected to a motor. Configuration and assembly of each leg can be

seen in Figure 8 (b). Both legs on each side (left/right) are controlled by the same motor and
connected through a sprocket and chain mechanism. The left and right legs are connected

by a shaft that is fixed on the robot’s body with a pillow bearing to support and maintain the
position of the legs. From preliminary study, the step sequence that is chosen for the MR2

is 4-2-3-1 which is shown in Figure 10. This is because a support triangle is formed during
the movement of the robot, and therefore, less energy is required [1]. This walking

mechanism is used because it gives wider step and more stable walking movement. This

mechanism has seven linkages and seven joints on each leg, where each part is made of
several aluminium plates which are easily to fabricate, light and cheap.

Figure 10: Sequence of 4-2-3-1 walking mechanism

150