 Here is a simplified Python code using the `pybullet` and `pytransform3d` libraries for the given task. Note that this code assumes you have a URDF file for the robot arm and the spherical mass is located at the end-effector.

```python
import pybullet as p
import pybullet_data
import pytransform3d as p3d
import urdf
import pybullet_urdf
import matplotlib.pyplot as plt

# Load the robot arm and spherical mass URDF
robot_urdf = urdf.load_urdf_file("path/to/robot_arm.urdf")
mass_urdf = urdf.load_urdf_file("path/to/spherical_mass.urdf")

# Create a physics client and load the world
client = p.connect(p.GUI)
p.setAdditionalSearchPath(pybullet_data.getDataPath())
start_state = p.loadURDF("robot.urdf", useFixedBase=True)

# Add the spherical mass to the world
mass_id = p.loadURDF(mass_urdf.toString(), basePosition=[0, 0, 0.1])

# Set joint angles
q = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6]
p.setJointMotorControl2(bodyIndex=start_state, jointIndex=0, controlMode=p.POSITION_CONTROL, targetPosition=q)
p.setJointMotorControl2(bodyIndex=start_state, jointIndex=1, controlMode=p.POSITION_CONTROL, targetPosition=q[1:])

# Define a function to plot the screw along a given axis
def plot_screw(axis, point, length, color='r', linewidth=2):
    theta = np.linspace(0, 2 * np.pi, 100)
    x = point[0] + length * axis[0] * np.cos(theta)
    y = point[1] + length * axis[1] * np.cos(theta - np.pi/2)
    z = point[2] + length * axis[2] * np.cos(theta - np.pi/2)
    p3d.plot_line(x, y, z, color=color, linewidth=linewidth)

# Define a function to plot the transformation about and along a screw axis
def plot_wrench(M, point, axis, length=0.1):
    F = M[:3]
    T = M[3:]
    plot_screw(axis, point, length * np.linalg.norm(F), color='g')
    plot_screw(axis, point, length * np.linalg.norm(T), color='b')

# Define the force/torque wrench at the TCP
wrench = np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1], [0, 0, 0]]).T

# Transform the wrench from the TCP to the base frame using the adjoint representation
T_tcp_to_base = p3d.compose_transforms(p.getLinkState(start_state, -1)[11], p.getLinkState(start_state, -1)[12])
wrench_base = np.dot(np.linalg.inv(T_tcp_to_base), wrench)

# Plot the wrench at the TCP and base frames
plot_wrench(wrench, [0, 0, 0.1], [0, 0, 1])
plot_wrench(wrench_base, [0, 0, 0], [0, 0, 1])

# Step the physics simulation
p.stepSimulation()

# Visualize the robot arm, spherical mass, and wrench
p.setAdditionalSearchPath(pybullet_data.getDataPath())
robot_model = pybullet_urdf.URDF2Mesh(robot_urdf)
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0, ymax=0, zmax=0.2, rgbaColor=[1, 0, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0, ymax=0, zmax=0.2, rgbaColor=[0, 1, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.2, rgbaColor=[0, 0, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.2, rgbaColor=[0, 0, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.1, rgbaColor=[1, 1, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.1, rgbaColor=[0, 1, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.1, rgbaColor=[1, 0, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.1, rgbaColor=[0, 0, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[1, 1, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[0, 0, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[1, 0, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[0, 1, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[1, 1, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[0, 0, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[1, 0, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[0, 1, 0, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[0, 0, 1, 1])
p.addUserDebugLine(xmin=0, ymin=0, zmin=0.1, xmax=0.1, ymax=0, zmax=0.05, rgbaColor=[1, 1, 1, 1])
p.addUserDebugLine(xmin