Il.mio.filmato.8.mp4
A microcontroller board is connected to two motors, forming a differential drive. Let l = 0.5 m be the distance between the wheels, and r = 0.2 m the radius of the two wheels. The microcontroller receives desired reference values for the speed and the angular velocity of the robot. These reference signals are sent through a serial interface. The microcontroller sends feedback messages back to the control PC to report a few status information.
• The control systems should compute the desired RPMs of the wheels using a differential drive kinematic model. • The control system must never generate PWM signals outside of the specifications of the motors. • If the requested speed and angular velocities of the robot are such that the necessary motor RPMs are outside the maximum specifications, the system should saturate them to the minimum/maximum allowed value. • An alert message (MCALE) should be sent at 1 Hz until the desired references are changed again and fall below the threshold.
• If no references (i.e., the MCREF command) are received from the PC for more than 5 seconds, the firmware should enter a timeout mode:
- Both motors velocity should be set to zero.
- Led D4 should blink at 5 Hz to signal timeout.
- When a new reference is read, then the led D4 should stop blinking and commands should be given again to the motors.
• The firmware must support receiving references at least at 10 Hz frequency (through a proper choice of baud rate).
• If button S5 is pressed, the firmware should enter a safe mode:
- Motors are stopped immediately, and reference signals are ignored until the microcontroller receives an enable message (HLENA).
- After exiting safe mode, the motors should be set to zero. Motors should move only after receiving a new reference. Once an enable command is received, the firmware should send a positive ack to the PC.
• The firmware should write on the LCD:
- First row: “STATUS: x”, where x = H/T/C (halt/timeout/controlled)
- Second row: “R: n1; n2”, where n1 and n2 are the applied RPM (e.g. “R: -20; 33”) o If the button S6 is pressed.
• $HLREF,omega,speed* where omega (rad/s) is the desired angular velocity and speed (m/s) is the desired linear velocity for the robot. • $HLENA* enables the firmware to send references to the motors (to exit safe mode) • $MCFBK,n1,n2,state* where n1 and n2 are the applied RPM values and state is 2 if the microcontroller is in safe mode, 1 if it is in timeout mode, 0 otherwise. • $MCALE,n1,n2*, where n1 and n2 are the compute wheel RPM values that are outside the maximum allowed values. • $MCTEM,temp* where temp is the temperature • $MCACK,msg_type,value* where msg_type is the command (e.g. ENA, SAT), and value is 1 if the message was applied and 0 otherwise (example: $MCACK,SAT,0* for a negative ack to the saturation command)
Board : dsPIC30F4011/4012
• Each motor can run from -50 to +50 RPMs • The motors are controlled through a PWM signal.
- The frequency must be 1 kHz.
- 50% duty cycle corresponds to 0 RPM, 0% corresponds to -60 RPM and 100% corresponds to 60 RPMs.
- A dead time of at least 3 microseconds should be used to prevent problems with the H-bridge controlling the motors. o Running the motors above +-50 RPMs can damage them and should be avoided.
| Authors | Github link |
|---|---|
| Gesualdo Sinatra | [https://github.com/aldoprogra][Gesualdo Sinatra] |
| Youssed Attia | [https://github.com/youssefattia98] [Youssed Attia] |
| Giovanni Di Marco | [https://github.com/Imdimark][Giovanni Di Marco] |