arduino四轮小车程序.zip

# kinematics Arduino Kinematics library for differential drive(2WD, 4WD) and mecanum drive robots. The library requires the following robot's specification as an input: - Robot's maximum RPM - Distance between wheels (base width) - Wheel's Diameter ## Functions #### 1. Kinematics::Kinematics(int motor_max_rpm, float wheel_diameter, float base_width, int pwm_bits) Object constructor which requires the robot's specification. - motor_max_rpm : Maximum RPM of the motor - wheel_diameter : Robot wheel's diameter expressed in meters - base_width : Distance between wheels - pwm_bits : PWM resolution of the Microcontroller. Arduino Uno/Mega, Teensy is 8 bits by default. #### 2. output getRPM(float linear_x, float linear_y, float angular_z) Returns a Vector of Motor RPMs from a given linear velocity in x and y axis and angular velocity in z axis using right hand rule. The returned values can be used in a PID controller as "setpoint" vs a wheel encoder's feedback expressed in RPM. - linear_x : target linear speed of the robot in x axis (forward or reverse) expressed in m/s. - linear_y : target linear speed of the robot in y axis (strafing left or strafing right for mecanum drive) expressed in m/s. - angular_z : target angular speed of the robot in z axis (rotating CCW or CW) rad/sec. #### 3. output getPWM(float linear_x, float linear_y, float angular_z) The same output as getRPM() function converted to a PWM value. The returned values can be used to drive motor drivers using the PWM signals. #### 4. velocities getVelocities(int motor1, int motor2) This is the inverse of getRPM(). Returns linear velocities in x and y axis, and angular velocity in z axis given two measured RPMs on each motor of a 2WD robot. The returned values can be used to calculate the distance traveled in a specific axis - where distance traveled is the product of the change in velocity and change in time. - motor1: left motor's measured RPM - motor2: right motor's measured RPM *each motor's RPM value must be signed. + to signify forward direction and - to signify reverse direction of the motor. #### 5. velocities getVelocities(int motor1, int motor2, int motor3, int motor4) The same output as No.4 but requires 4 measured RPMs on each motor of a 4WD robot. This can be used for both 4 wheeled differential drive and mecanum drive robots. - motor1: front left motor's measured RPM - motor2: front right motor's measured RPM - motor3: front right motor's measured RPM - motor4: front right motor's measured RPM *each motor's RPM value must be signed. + to signify forward direction and - to signify reverse direction of the motor. ## Data structures #### 1. output Struct returned by getRPM() and getPWM used to store PWM or RPM values. ``` struct output{ int motor1; int motor2; int motor3; int motor4; }; ``` * each returned motor RPM or PWM value is signed to signify the motor's direction. + forward direction ; - reverse direction. #### 2. velocities Struct returned by getVelocities() used to store linear velocities in x and y axis, and angular velocity in z axis (right hand rule). ``` struct velocities { float linear_x; float linear_y; float angular_z; }; ``` * linear_x and linear_y are expressed in m/s. angular_z is expressed in rad/s