This section describes how to prepare for the grasp planning stage when a new robot is introduced. HRP2JRL is used as an example of a robot model.
Edit the file “graspPlugin/RobotModels/HRP2JRL/HRP2.yaml” in a similar manner to that shown below. The meaning of each entry is explained on the right, after the “%” sign.
graspPluginSetting: name: HRP2 %Name of the Robot base: CHEST_JOINT1 %Base link used when IK is solved palm: RARM_JOINT5 %Wrist link used when IK is solved fingerEnds: [ RHAND_JOINT1, RHAND_JOINT4 ] %Finger-tip links prehensionList: [ prehension ] %File with reference postures for grasping (prehension.pos, prehension.prm), Multiple reference postures can be specified. armStandardPose: [0, 0, 0, -1.57, 0, 0] %Reference posture of the arm when IK is solved by iterative calculations(The Joint angle from the base to palm) fingerOpenPose: [0.78, -0.78, 0.78, -0.78, 0.78, -0.78] %Pose with the fingers opened to the maximum possible extent. interlink: [ [ RARM_JOINT6, 1.0 , RHAND_JOINT0, -1.0, RHAND_JOINT1, 1.0 ],[RHAND_JOINT2, -1.0, RHAND_JOINT3, 1.0, RHAND_JOINT4, -1.0]]%Interlocking link GrasplotPluginDir: Plugin % Name of the directory that contains the program which solves a specific ID.
Next, the “prehension.prm” and “prehension.pos files” are specified. These files are stored in the “graspPlugin/RobotModels/HRP2JRL/data” path.
Note:
The “prehension.prm” file contains descriptors that hold parameters related to the grasp types (3-fingered fingertip grasp, 4-fingered fingertip grasp, enveloping grasp, etc.) and the “prehension.pos” file contains the standard postures while grasping in any of the above grasp types.
Reference_Motion prehension Finger0Contact 0 1 0 Finger0Comp 0 0 0 Finger0Close 0.01 -0.01 0.01 Finger1Contact 0 1 0 Finger1Comp 0 0 0 Finger1Close -0.01 0.01 -0.01 GRCdes_Position 0.0 0.0 -0.19 GRCmax_Position 0.0 0.0 -0.30 GRCmin_Position 0.0 0.0 -0.19 GRCdes_Rpy -1.57 0 0 GRCmax_Rpy -1.57 0 0 GRCmin_Rpy -1.57 0 0 GRCdes_Edges 0.05 0.05 0.05 GRCmax_Edges 0.30 0.30 0.10 GRCmin_Edges 0.01 0.01 0.01 Max_Load 1.0 Min_Load 0
For example, the entries in this file are as shown below.
0 0.78 -0.78 0.78 -0.78 0.78 -0.78
The first 0 can be any arbitrary number, but the numbers after that specify the finger joint angles in the same order as specified in the VRML.
With this, the setup for using the Grasp Plug-in is complete.
GRCmax
GRCdes