Grippers control

Index

Important note on grippers control

Currently, YuMi only allows very simple control of the grippers, by setting an effort command in the range [-20, 20].

Grippers state

If you want to check the grippers position at any moment, run the following command:

rostopic echo /yumi/gripper_states

ROS service interface

For the ROS service interface the YuMi grippers have been assigned the following IDs:

Left gripper: 1
Right gripper: 2

Direct rosservice calls

To open the left gripper:

rosservice call /yumi/yumi_gripper/release_grasp "gripper_id: 1"

To open the right gripper:

rosservice call /yumi/yumi_gripper/release_grasp "gripper_id: 2"

To close the left gripper:

rosservice call /yumi/yumi_gripper/do_grasp "gripper_id: 1"

To close the right gripper:

rosservice call /yumi/yumi_gripper/do_grasp "gripper_id: 2"

Python service calls

To close the right gripper:

service_proxy = rospy.ServiceProxy("/yumi/yumi_gripper/do_grasp", YumiGrasp)
resp = service_proxy(gripper_id) #gripper_id is the ID of your gripper, 1 or 2
rospy.sleep(3)

To open the right gripper:

service_proxy = rospy.ServiceProxy("/yumi/yumi_gripper/release_grasp", YumiGrasp)
resp = service_proxy(gripper_id) #gripper_id is the ID of your gripper, 1 or 2
rospy.sleep(3)

ROS topic interface

Directly publishing to each gripper topic

To send an effort command to the left gripper:

rostopic pub /yumi/gripper_l_effort_cmd std_msgs/Float64 "data: effort_command"

On the other hand, to send an effort command to the right gripper:

rostopic pub /yumi/gripper_r_effort_cmd std_msgs/Float64 "data: effort_command"

Where effort_command can be replaced with the effort value that you want.

Python topic publishers

To send an effort command to the left gripper:

gripper_l_cmd_pub = rospy.Publisher("/yumi/gripper_l_effort_cmd", Float64, queue_size=1)
gripper_l_cmd_msg = effort_command
gripper_l_cmd_pub.publish(effort_command)

On the other hand, to send an effort command to the right gripper:

gripper_r_cmd_pub = rospy.Publisher("/yumi/gripper_r_effort_cmd", Float64, queue_size=1)
gripper_r_cmd_msg = effort_command
gripper_r_cmd_pub.publish(effort_command)