zy-zong/ece470projectbasketballshoot

ECE470ProjectBasketballShoot

Group members：Yiqun Niu, Zhenyu Zong, Xiang Li

UPDATE 2

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Methods

• Download the V-rep and run it with

    $ ./vrep .sh

• Choose UR3.ttm and Jaco hand.ttm models from Model browser, connect them with Assemble / Disassemble icon. The scene is saved as Update2Scene.tttt file.

• Delete default child script from the robot because we will run the script with outside python code.

• Make sure the documents vrep.py, vrepConst.py and remoteApi.dylib are in the path:

V-REP_PRO_EDU_V3_6_2_Mac/programming/remoteApiBindings/python/python

• The script code is in the file example.py. This file is based on the codes of the example given by ece470_vrep_Linux.

Script Codes

• Make a martix of the position, which is the angle of every joint.

Goal_joint_angles = np.array([[0,0.5*np.pi,-0.5*np.pi,0.5*np.pi,-0.5*np.pi,np.pi], \
				[-0.5*np.pi,0,-0.5*np.pi,0,0.5*np.pi,-0.5*np.pi],\
				[0.5*np.pi,-0.5*np.pi,-0.5*np.pi,0,0,-0.5*np.pi]])

• Then use SetJointPosition function to move the UR3 in simulator. The SetJointPosition function is formed by simxSetJointTargetPosition function, which can move only one joint in a particular angle SetJointPosition function call simxSetJointTargetPosition function 6 time for the 6 joints. The three calls set the six joints for three times.

for i in range(3):
	SetJointPosition(Goal_joint_angles[i])
	time.sleep(2)

UPDATE 3

video

Forward Kinematics

• The script code is in the file update3.py. Run the code in a terminal with the Vrep simulator open, the arm will initialize its position and take commands from the user. The user should type in six angles in degrees which be added to the current angle to move the UR3 arm. You have at most ten chances to try to move the arm. The transform matrix from the home position to the new position will be printed on the screen, which demostrates forward kinematics.

JacoHand Gripper

• The hand is based on child script. In JacoHand's child script file, we need to do some changes for enabling the hand to open and close. Codes are referenced from this website.

sig=sim.getStringSignal('jacoHand')
if sig~=nil then
simClearStringSignal('jacoHand')
if sig=='true' then closing=true else closing=false end
end

• Then enable the JacoHand to grasp and release things. In update3.py file JacoHandGrasp function, send the command to JacoHand with codes:

vrep.simxSetStringSignal(clientID,'jacoHand','true',vrep.simx_opmode_oneshot)
vrep.simxSetStringSignal(clientID,'jacoHand','false',vrep.simx_opmode_oneshot)

• These instructions can open and close the hand.

UPDATE 4

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Decision making

• Add one Cylinder Item cynlinder0 in the scene. Change the properties of the iteam to make it detectable: In its Scene Object Properties window, click common and enable Dectable.

• The robot keeps waiting if nothing is passed to the Jacohand. If no item detected, send back response No items, wait! and wait. Otherwise, JacoHand will grasp the item and move it to the destination.

Perception

• Robot needs to detect whether there is available items for graspoing. Use Proximity Sensor to sense the item. First, add a cone proximity sensor to the Jacohand. Then set the Scene Object Properties. The sensor should sense all dectectable objects in the scene. Modify the scan range to make it suitable by clicking Show volume parameters.

• Enable the sensor in codes. Write a new function JacoHandHasItem to check whether the proximity sensor dectect yhe item or not. Proximity sensor needs to be run twice: Run with simx_opmode_streaming mode first time and simx_opmode_buffer second time. time.sleep(1) must be added, or two instructions will be done at the same time, resulting the dection fail. State indicate whether the item is sensed. Idea comes from this website, which tells us how to use vision sensor.

ret, state, arr1, value, arr2 = vrep.simxReadProximitySensor(clientID, proximity_sensor_handle, vrep.simx_opmode_streaming)
time.sleep(0.1)
ret, state, arr1, value, arr2 = vrep.simxReadProximitySensor(clientID, proximity_sensor_handle, vrep.simx_opmode_buffer)