Pyserial and servo functions

A developer is building a 3-degree-of-freedom robotic arm using a BeagleY-AI single-board computer and a Pololu 18-channel Maestro servo controller, with AI-generated Python code. The project currently lacks camera vision and physical construction, but the developer has shared a starter script for controlling the servos via USB.

I wanted to make a 3 DoF arm with my 64-bit BeagleY-AI and a controller for handling servo motors. I picked the beagleboard.org http://beagleboard.org BeagleY-AI and the pololu.com http://pololu.com 18 channel Maestro. Luckily for me, I had some servo motors leftover from another project I could use. I am only using three servo motors for this project. This way I can have a base, shoulder, and elbow for the arm. The source code is basically AI generated with an emphasis on python3. I have had to change a lot of the source code to function properly and with little bugs. It is still a work in progress since the arm is not physically built yet and the code needs better progression directed at it. Here you can see a simple connection from a BeagleY-AI to Maestro servo controller. It requires a USB 2.0 type A at least to a mini USB cable. You will also need a few jumper wires for powering the servo s . Here, you can see a pinout of the Maestro used in the project. The SBC single board computer used can be found here: https://www.beagleboard.org/boards/beagley-ai https://www.beagleboard.org/boards/beagley-ai While the pins to be utilized on the board can be found at this neat project online: https://pinout.beagley.ai/ https://pinout.beagley.ai/ So far, I have no incorporated camera vision. I am also going to post a starter script for using the board and servo controller. python import sysimport mathimport timeimport usb.coreimport usb.util ========================================== 1. HARDWARE & DEVICE CONFIGURATION ==========================================VENDOR ID = 0x1FFBPRODUCT ID = 0x008B Mini Maestro 18-Channeldevice = usb.core.find idVendor=VENDOR ID, idProduct=PRODUCT ID if device is None: print "Error: Maestro device not found. Check physical connections." sys.exit 1 ========================================== 2. ARM GEOMETRY & SMOOTHING MATRIX ==========================================L1 = 100.0 Base height mm L2 = 120.0 Upper arm length mm L3 = 150.0 Forearm length mm Matrix containing mapping data and on-chip kinematics configuration Speed: 1 = 0.025 μs/ms. Try values between 10 and 50 for gentle movement. Acceleration: 1 = 0.0003125 μs/ms². Try values between 1 and 10.SERVO MATRIX = { "base": {"ch": 0, "min deg": -90, "max deg": 90, "min us": 1000, "max us": 2000, "speed": 15, "accel": 4}, "shoulder": {"ch": 1, "min deg": 0, "max deg": 180, "min us": 900, "max us": 2100, "speed": 12, "accel": 3}, "elbow": {"ch": 2, "min deg": -135,"max deg": 135,"min us": 1000, "max us": 2000, "speed": 20, "accel": 5}} ========================================== 3. MAESTRO HARDWARE INTERFACES ==========================================def set hardware limits dev, channel, speed, accel : """Configures on-chip speed and acceleration profile curves.""" Speed command: 0x87, Channel, Low Bits, High Bits speed low = speed & 0x7F speed high = speed 7 & 0x7F dev.write 1, 0x87, channel, speed low, speed high Acceleration command: 0x89, Channel, Low Bits, High Bits accel low = accel & 0x7F accel high = accel 7 & 0x7F dev.write 1, 0x89, channel, accel low, accel high def send maestro command dev, channel, target us : """Sends immediate position target. Microcontroller manages profile execution.""" target val = int target us 4 low bits = target val & 0x7F high bits = target val 7 & 0x7F try: dev.write 1, 0x84, channel, low bits, high bits except usb.core.USBError as e: print f"USB Error: {e}" ========================================== 4. KINEMATICS ENGINE ==========================================def calculate ik x, y, z : """Calculates target positions for X,Y,Z Cartesian points.""" try: theta 0 = math.atan2 y, x r = math.sqrt x 2 + y 2 z rel = z - L1 D = math.sqrt r 2 + z rel 2 if D L2 + L3 or D < abs L2 - L3 : return None cos theta 2 = D 2 - L2 2 - L3 2 / 2 L2 L3 theta 2 = math.acos cos theta 2 alpha = math.atan2 z rel, r cos beta = L2 2 + D 2 - L3 2 / 2 L2 D beta = math.acos cos beta theta 1 = alpha + beta return { "base": math.degrees theta 0 , "shoulder": math.degrees theta 1 , "elbow": math.degrees theta 2 } except ValueError, ZeroDivisionError : return Nonedef scale angle to us angle deg, config : constrained = max config "min deg" , min config "max deg" , angle deg deg range = config "max deg" - config "min deg" us range = config "max us" - config "min us" return int config "min us" + constrained - config "min deg" / deg range us range ========================================== 5. EXECUTION PIPELINE ==========================================WAYPOINTS = 150.0, -50.0, 120.0 , 150.0, 50.0, 120.0 , 120.0, 50.0, 160.0 , 120.0, -50.0, 160.0 , try: print "\nInitializing hardware profiles inside Maestro memory..." for joint, config in SERVO MATRIX.items : set hardware limits device, config "ch" , config "speed" , config "accel" print f" {joint.capitalize } Channel {config 'ch' }: Speed limit = {config 'speed' }, Accel limit = {config 'accel' }" print "\nHardware smoothing active. Processing loop running..." while True: for target pt in WAYPOINTS: angles = calculate ik target pt if angles is None: continue print f"Sending hardware command packet to: {target pt}" Fire target coordinates directly. The Maestro handles acceleration profiles. for joint, config in SERVO MATRIX.items : target pulse = scale angle to us angles joint , config send maestro command device, config "ch" , target pulse Allow time for the physical arm to complete its hardware-ramped trajectory time.sleep 2.5 except KeyboardInterrupt: print "\nShutting down automated loop safely." finally: Clear active limits on exit to ensure standard script resets for joint, config in SERVO MATRIX.items : try: set hardware limits device, config "ch" , 0, 0 except: pass usb.util.dispose resources device This code was AI generated for pyusb. If you take on the task, remember to alter this AI generated code at you own discretion and do not hold others in contempt for AI generation code supply. For me, I used pyserial instead of pyusb to get this AI generated code in working order. If you would like to learn more about why using AI is okay or why this code works or does not, please contact me or test at you own volition. 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