def __init__(self, serial_port, has_sensor=False, start_heartbeat=True, baudrate=115200, timeout=0.05):
"""
:param serial_port: Serial device to use for communication (i.e. "COM3" or "/dev/tty.usbmodem0")
:param has_sensor: Whether or not the bldc motor is using a hall effect sensor
:param start_heartbeat: Whether or not to automatically start the heartbeat thread that will keep commands
alive.
:param baudrate: baudrate for the serial communication. Shouldn't need to change this.
:param timeout: timeout for the serial communication
"""
if serial is None:
raise ImportError("Need to install pyserial in order to use the VESCMotor class.")
self.serial_port = serial.Serial(port=serial_port, baudrate=baudrate, timeout=timeout)
if has_sensor:
self.serial_port.write(encode(SetRotorPositionMode(SetRotorPositionMode.DISP_POS_OFF)))
self.heart_beat_thread = threading.Thread(target=self._heartbeat_cmd_func)
self._stop_heartbeat = threading.Event()
if start_heartbeat:
self.start_heartbeat()
# check firmware version and set GetValue fields to old values if pre version 3.xx
version = self.get_firmware_version()
if int(version.split('.')[0]) < 3:
GetValues.fields = pre_v3_33_fields
# store message info for getting values so it doesn't need to calculate it every time
msg = GetValues()
self._get_values_msg = encode_request(msg)
self._get_values_msg_expected_length = msg._full_msg_size
def set_servo(self, new_servo_pos):
"""
:param new_servo_pos: New servo position. valid range [0, 1]
"""
self.write(encode(SetServoPosition(new_servo_pos)))
def set_duty_cycle(self, new_duty_cycle):
"""
:param new_duty_cycle: Value of duty cycle to be set (range [-1e5, 1e5]).
"""
self.write(encode(SetDutyCycle(new_duty_cycle)))
def set_current(self, new_current):
"""
:param new_current: new current in milli-amps for the motor
"""
self.write(encode(SetCurrent(new_current)))
def set_rpm(self, new_rpm):
"""
Set the electronic RPM value (a.k.a. the RPM value of the stator)
:param new_rpm: new rpm value
"""
self.write(encode(SetRPM(new_rpm)))
:ivar pos_mode: Value of the mode
"""
DISP_POS_OFF = 0
DISP_POS_MODE_ENCODER = 3
DISP_POS_MODE_PID_POS = 4
DISP_POS_MODE_PID_POS_ERROR = 5
id = VedderCmd.COMM_SET_DETECT
fields = [('pos_mode', 'b')]
class SetServoPosition(metaclass=VESCMessage):
"""Sets the position of s servo connected to the VESC.
:ivar servo_pos: Value of position (range [0, 1])
"""
id = VedderCmd.COMM_SET_SERVO_POS
fields = [('servo_pos', 'h', 1000)]
class Alive(metaclass=VESCMessage):
"""Heartbeat signal to keep VESC alive"""
id = VedderCmd.COMM_ALIVE
fields = []
# statically save this message because it does not need to be recalculated
alive_msg = encode(Alive())
