## 4 Experiment
### Experiments Setup  
The 3 WIDWIS mobile robot is shown in Figure 5. The experiments were carried out in a test area, shown in Figure 5, which is approximately 10 m long and 6 m wide. The ground material of the test area is plywood, which is overall flat without significant gaps or slopes. It is surrounded by walls of suitable height. The 3 WIDWIS mobile robot has a lateral length of 300 mm and a longitudinal length of 280 mm. The overall frame is composed of epoxy plates and 3D-printed components. The three-wheel modules are arranged in an equilateral triangle configuration. The wheeled encoder is positioned between the two rear wheels of the 3 WIDWIS robot, while the laser rangefinder sensors are placed on the left and right sides at a 90-degree arrangement. The control board is located at the center of the robot body. The 3 WIDWIS mobile robot has a lateral length of 300 mm and a longitudinal length of 280 mm. The overall frame is composed of epoxy plates and 3D-printed components. The three-wheel modules are arranged in an equilateral triangle configuration. The wheeled encoder is positioned between the two rear wheels of the 3 WIDWIS mobile robot, while the laser rangefinder sensors are placed on the left and right sides at a 90-degree arrangement. The control board is located at the center of the robot body.  
The control board used is the RoboMaster Type A development board, with an MCU of STM32F427 IIIH6. The Inertial Measurement Unit (IMU) used is BMI088, and the odometry is OPS-9. The laser rangefinder sensor used is SICK DT35-B15251. ODrive is a motor controller specifically designed for controlling brushless DC motors (BLDC). C610 is the DJI ESC for the M2006 motor. Encoder (ENC) and Controller Area Network (CAN) refer to the driving methods for driving motor and steering motor, respectively.  
Figure 6 presents the hardware framework of the 3 WIDWIS mobile robot. IMU can provide 1000 Hz feedback on the robot's current acceleration and angular velocity. By processing this information, the robot's pose in the robot coordinate system can be obtained  
Figure 5: The 3 WIDWIS mobile robot.  
at 100 Hz. In this experiment, the laser rangefinder was only used to record the pose in global coordinate system of the 3 WIDWIS mobile robot in test area. This pose will be used as the ground truth of the experiment.  
Before each experiment begins, the robot needs to be moved to the starting point and initialized. The expected trajectory and trajectory tracking task are sent to the robot via a remote host computer. As the robot starts moving, it continuously records the current pose in global coordinate system. The output data will be provided with an external text file. The controller will constantly give the control quantities calculated within each current control period and continuously reduce the position and heading angle error.  
To verify whether our proposed approach, DMPC, can effectively improve tracking performance and reduce tracking error or not, two types of trajectory tests (a straight-line trajectory and a complex curve trajectory) are conducted. The performance of the controller designed in this paper was analyzed comprehensively.