Pybullet - Gripper is not able to Grasp Object

Question

I am using the Kinova Jaco robotic arm with the j2n6s300.urdf file and I simply want to grasp a mug from the side and live it up. However, the gripper is not able to pick up the mug. It seems that there is an "invisible" barrier between gripper fingers and mugs. If I lift the gripper the mug stays where it was.

However, if I run the same code using the Franka Panda robot (slight adaptions with joints) I can lift the mug. What is my problem? Is it related to the urdf file?

This is my code:

import os 
import pybullet as pb
import pybullet_data
import math
import time
import pybullet_data as pd 
jaco_path = 'jaco_reza/j2n6s300.urdf'
pb.connect(pb.GUI)
path = pd.getDataPath()

jaco_orientation_euler = [0,math.pi/2,0]
jaco_orientation_quaternion = pb.getQuaternionFromEuler(jaco_orientation_euler)
jacoUid = pb.loadURDF(os.path.join(jaco_path,), useFixedBase=True, basePosition=[-0.63,0,0.46], baseOrientation=jaco_orientation_quaternion)

pos, ori = pb.getBasePositionAndOrientation(jacoUid)
tableUid = pb.loadURDF(os.path.join(pybullet_data.getDataPath(), "table/table.urdf"),basePosition=[0.5,0,-0.66])

mug_orientation_euler = [0,0,-math.pi/2]
mug_orientation_quaternion = pb.getQuaternionFromEuler(mug_orientation_euler)

mugUid = pb.loadURDF(os.path.join(pybullet_data.getDataPath(), "objects/mug.urdf"),basePosition=[0.148,0,-0.035], baseOrientation=mug_orientation_quaternion)

pb.setGravity(0,0,-10)

pb.resetDebugVisualizerCamera(
    cameraDistance=1.5, 
    cameraYaw=0, 
    cameraPitch=-20, 
    cameraTargetPosition=[-0.15,0,0.1])

# #init Jaco Position
rest_poses = [0,0,0,1.5,1.4,1.5,0,1.5,3,0,0.5,0,0.5,0,0.5]
for i in range(15):
     pb.resetJointState(jacoUid,i, rest_poses[i])


fingerAngle = 0.7 

for i in range(180):
    pb.setJointMotorControl2(jacoUid,9,pb.POSITION_CONTROL,targetPosition=fingerAngle,force=2000)
    pb.setJointMotorControl2(jacoUid,11,pb.POSITION_CONTROL,targetPosition=fingerAngle,force=1000)
    pb.setJointMotorControl2(jacoUid,13,pb.POSITION_CONTROL,targetPosition=fingerAngle,force=1000)
    pb.stepSimulation()
    fingerAngle += 0.1 / 100.
    if fingerAngle > 2:
        fingerAngle = 2 #upper limit
    time.sleep(0.02)

for i in range(20):
    print(pb.getJointState(jacoUid,4)[0])
    pb.setJointMotorControl2(jacoUid, 4,
                                        pb.POSITION_CONTROL,
                                        targetPosition=1)
    pb.stepSimulation()

while True:
    pb.configureDebugVisualizer(pb.COV_ENABLE_SINGLE_STEP_RENDERING) 
    pb.stepSimulation()

I tried to change the .urdf file of the Kinova robotic but it was not working and I have the feeling that I am missing an important step.

Pybullet - Gripper is not able to Grasp Object

0 Answers0