**4.1 Experiment of horizontal motion**

This experiment combines surge and sway together to verify the motion characteristics of the vehicle in horizontal plane. We carried out three experiments: **Case 1**:

step 1. Surge (Move forward in X axis);

step 2. Right steering (Turn right about 90*o*);

step 3. Sway (Move forward along Y axis.)

**Case 2**:

step 1. Surge (Move forward in X axis);

step 2. Left steering (Turn left about 90*o*);

step 3. Sway (Move forward along Y axis.)
