# Joint Control

For a serial multi-joint robot, the control of the joint space is to control the variables of each joint so as to make each joint reaches a target position at a certain speed.

Notice: When setting the angle, the values corresponding to different manipulators are different. Refer to the parameter introduction section for more information.

## 1 Single-Joint Control

1.1 `send_angle(id, degree, speed)`

• Function: to sends a specified single joint motion to a specified angle.
• Parameters:
• `id`: to stand for the joints of a robot arm. Six axis means that the robot arm has six joints, and four-axis means it has four joints. There are specific representation methods therefor.The method to represent the joint 1:`Angle.J1.value`. (It can also be represented by numbers 1-6.)
• `degree`: means the angle of a joint.
• `speed`: means the movement speed of the robot arm, ranging from 0 to 100.
• Return value: None

1.2 `set_encoder(joint_id, encoder)`

• Function: to sends a specified single joint motion to a specified potential value.
• Parameters:

• `joint_id`: to stand for the joints of a robot arm. Six axis
``````means that the robot arm has six joints, and four-axis means it
has four joints. There are specific representation methods
therefor. The method to represent the joint 1:` Angle.J1.value`.
(It can also be represented by numbers 1-6.)
``````
• `encoder`:means the potential value of the robot arm, ranging from 0 - 4096.
• Return value: None

## 2 Multi-Joint Control

2.1 `get_angles()`

• Function: to get the angels of all joints.

• Return Value: `List`: a list of floating point values which represent the angles of all joints

2.2 `send_angles(degrees, speed)`

• Function: to send all angles to all joints.
• Parameters:
• `degrees`: (List [float]) contains the angles of all joints. A six-axis robot has six joints, so the length is 6; and the four-axis length is 4. The representation method is [20, 20, 20, 20, 20, 20]; value range: about -170 - 170. Each joint of the four-axis robot is different. See the table above for details.
• `speed`: means the movement speed of the robot arm, ranging from 0 to 100.
• Return value: None

2.3 `set_encoders(encoders, sp)`

• Function: Send potential values to all joints of the robotic arm.
• Parameters:
• `encoder`: means the potential of the robot arm, ranging from 0 - 4096. Six axis length is 6, and four axis length is 4. The way to represent:[2048, 2048, 2048, 2048, 2048, 2048].
• `sp`: means the movement speed of the robot arm, ranging from 0 to 100.
• Return value: None

2.4 `sync_send_angles(degrees, speed, timeout=7)`

• Function: to send an angle synchronously; return when reaching a target point.
• Parameters:
• `degrees`: A list of angle values of each joint`List[float]`.
• `speed`: (`int`) means the movement speed of the robot arm, ranging from 0 to 100.
• `timeout`: The default time is 7s.
• Return value: None

2.5 `get_radians()`

• Function: to get the radian of all joints.
• Return value: `list`: a list containing radian values of all joints

2.6 `send_radians(radians, speed)`

• Function: to send radian values to all joints.
• Parameters:
• `radians`: means the radian values of the robot arm, ranging from -5 to 5.
• Return value: `list`: a list containing radian values of all joints.

## 3 Simple Demo

• Codes for MyCobot:
``````from pymycobot.mycobot import MyCobot
from pymycobot.genre import Angle
from pymycobot import PI_PORT, PI_BAUD  # When using the Raspberry Pi version of mycobot, you can refer to these two variables to initialize MyCobot
import time

# MyCobot class initialization requires two parameters:
#   The first is the serial port string, such as:
#       linux:  "/dev/ttyUSB0"
#          or "/dev/ttyAMA0"
#       windows: "COM3"
#   The second is the baud rate::
#       M5 version is:  115200
#
#    Example:
#       mycobot-M5:
#           linux:
#              mc = MyCobot("/dev/ttyUSB0", 115200)
#          or mc = MyCobot("/dev/ttyAMA0", 115200)
#           windows:
#              mc = MyCobot("COM3", 115200)
#       mycobot-raspi:
#           mc = MyCobot(PI_PORT, PI_BAUD)
#
# Initiate a MyCobot object
# Create object code here for windows version
mc = MyCobot("COM3", 115200)

#By passing the angle parameter, let each joint of the robotic arm move to the position corresponding to [0, 0, 0, 0, 0, 0]
mc.send_angles([0, 0, 0, 0, 0, 0], 50)

# Set the waiting time to ensure that the robotic arm has reached the specified position
time.sleep(2.5)

# Move joint 1 to the 90 position
mc.send_angle(Angle.J1.value, 90, 50)
# Set the waiting time to ensure that the robotic arm has reached the specified position
time.sleep(2)

# The following code can make the robotic arm swing left and right
# set the number of loops
while num > 0:

# Move joint 2 to the 50 position
mc.send_angle(Angle.J2.value, 50, 50)

# Set the waiting time to ensure that the robotic arm has reached the specified position
time.sleep(1.5)

# Move joint 2 to the -50 position
mc.send_angle(Angle.J2.value, -50, 50)

# Set the waiting time to ensure that the robotic arm has reached the specified position
time.sleep(1.5)

num -= 1

#Make the robotic arm retract. You can manually swing the robotic arm, and then use the get_angles() function to get the coordinate sequence,
# use this function to let the robotic arm reach the position you want.
mc.send_angles([88.68, -138.51, 155.65, -128.05, -9.93, -15.29], 50)

# Set the waiting time to ensure that the robotic arm has reached the specified position
time.sleep(2.5)

# Let the robotic arm relax, you can manually swing the robotic arm
mc.release_all_servos()
``````
• Codes for MyPalletizer:
``````from pymycobot.mypalletizer import MyPalletizer
from pymycobot.genre import Angle
import time
# import the project package

# Initiate a MyPalletizer object
mc = MyPalletizer("COM3",115200)
# By passing the angle parameter, let each joint of the robotic arm move to the position corresponding to [0, 0, 0, 0, speed]
mc.send_angles([0, 0, 0, 0,], 50)
#  Set the waiting time to ensure that the robotic arm has reached the specified position
time.sleep(2)

# Move joint 1 to the 50 position
mc.send_angle(1,20,50)
# Set the waiting time to ensure that the robotic arm has reached the specified position
time.sleep(2)
# set variable "num"
num = 2
# set the number of loops
while num > 0:
mc.send_angle(2,20,50)
time.sleep(2)
mc.send_angle(2,(-20),50)
time.sleep(2)
num -= 1

# make robot arms reach the specified position
mc.send_angles([-0.87, 41.66, -12.13, -0.17], 50)
#  Let the robotic arm relax, you can manually swing the robotic arm
mc.release_all_servos()
``````