B-Robot CHALLENGES: Racing!

The general behaviour of the B-robot EVO 2 is defined by a group of parameters. They are set in the Arduino CODE BROBOT_EVO2_XX.ino file :

// NORMAL MODE PARAMETERS  
 #define MAX_THROTTLE 550  MAXIMUM VELOCITY
 #define MAX_STEERING 140 MAXIMUM SPINNING VELOCITY
 #define MAX_TARGET_ANGLE 14 MAXIMUM ANGLE REACHED WHEN MOVING

// PRO MODE = MORE AGGRESSIVE (MAXIMUM SETTINGS)
 #define MAX_THROTTLE_PRO 860  MAXIMUM VELOCITY. PRO MODE
 #define MAX_STEERING_PRO 280 MAXIMUM SPINNING VELOCITY. PRO MODE
 #define MAX_TARGET_ANGLE_PRO 32  MAXIMUM ANGLE REACHED WHEN MOVING. PRO MODE

// Default control terms for EVO 2 THESE PARAMETERS DEFINE THE GENERAL BEHAVIOUR OR THE ROBOT (STABILITY AND SPEED OF RESPONSE) MORE INFO ABOUT THE B-ROBOT PID PARAMETERS HERE. WE ARE NOT GOING TO PLAY WITH THEM HERE. 
FOR THAT, TAKE A LOOK TO THE CHALLENGE: "The Robotic Waiter" 
 #define KP 0.32 // 0.14
 #define KD 0.050 // 0.028
 #define KP_THROTTLE 0.075 //0.075
 #define KI_THROTTLE 0.1 // 0.1
 #define KP_POSITION 0.06 //0.055
 #define KD_POSITION 0.45 //0.5
 //#define KI_POSITION 0.02

A good idea is to set the PRO parameters (in the Arduino CODE: BROBOT_EVO2_XX.ino file)  as the “testing” parameters. So, if you tap on the PRO button while using the CONTROL APP, you will activate, during the race, the PRO configuration you have previously set.

Tuning example: Increase slightly the MAX_THROTTLE_PRO, MAX_STEERING_PRO, MAX_TARGET_ANGLE_PRO values and see what happens. If you can control the B-robot with those parameters, push forward and increase them a little bit more! Keep in mind that for every circuit, a different set of parameters will work better than others.

Example:

1. Open the BROBOT_EVO2_XX.ino file with the Arduino IDE.  Set the parameters as below:

// PRO MODE = MORE AGGRESSIVE (MAXIMUM SETTINGS)
#define MAX_THROTTLE_PRO 600 
#define MAX_STEERING_PRO 200
#define MAX_TARGET_ANGLE_PRO 25

2. Compile the code and upload it to the Arduino Leonardo.

3. Turn the B-robot EVO 2 and check if you can manage to control it easily. If not, reduce the values (play a little with them).

// PRO MODE = MORE AGGRESSIVE (MAXIMUM SETTINGS)
 #define MAX_THROTTLE_PRO 860 
 #define MAX_STEERING_PRO 280
 #define MAX_TARGET_ANGLE_PRO 32

A high MAX_THROTTLE_PRO value will make the B-robot faster, but less stable if you do not recover the vertical position smoothly.

A high MAX_STEERING_PRO value will let the B-robot to rotate faster but it will make it harder to control precisely when turning.

A high MAX_TARGET_ANGLE_PRO value will let the B-robot to reduce its angle in relation with the horizontal plane (the floor) but that will make harder to recover and make a turn (increase the top speed but reduce manoeuvrability)

In Robotics, you will always have to find the balance between accuracy and speed. Some robots with a set of “already know” positions can achieve high velocity and precision at the same time (assembling robots) but that condition will not be certain for robot which have to adapt it behaviour continuously. A good example of an adapting robot is the Handle Robot, capable of change its centre of gravity location as it moves (and jumps). Pay attention in the video to its arms and head and how it moves them in order to keep the balance.

Robotic arm assembling: VIDEO  And example of how robotics arms can assembly a car in Mercedes Benz, Rastatt plant. Germany.

Cheetah robot running: VIDEO, A very impressive running robot capable of getting up to 28.3 mph (actually, faster than Usain Bolt’s)