Building a simple robot in VREP and controlling it through ROS

In this demostration a simple two wheel differential drive robot is made in VREP. The robot consist of two powered wheels and a castor wheel. Furthermore, the robot is equipped with an ultra-sonic sensor. The associated Lua script with the robot publishes a topic "/frontUS" on which it sends ultra-sonic range measurements. The robot subscribes to a topic "/cmd_vel" over which it recieves the left and right wheel velocity commands.

[@jn8194]

Thank you for that tutorial. It pushed me with learning LUA, ROS and V-Rep. Have a nice day :)

[@ahmadkamalnasir6290]

function cmdVel_Subscriber(msg)
-- Command velocity callback function
local V = msg.linear.x
local W = msg.angular.z
local Vl = V + L/2 * W
local Vr = V - L/2 * W
sim.setJointTargetVelocity(hLeftMotor, Vl)
sim.setJointTargetVelocity(hRightMotor, Vr)
end
function sysCall_init()
-- do some initialization here:
hLeftMotor = sim.getObjectHandle('LeftMotor')
hRightMotor = sim.getObjectHandle('RightMotor')
L = 0.06
hFrontUS = sim.getObjectHandle('FrontUS')
hRosPubFrontUS = simROS.advertise('/frontUS', 'std_msgs/Float32')
hRosSubCmdVel = simROS.subscribe('/cmd_vel', 'geometry_msgs/Twist', 'cmdVel_Subscriber')
end
function sysCall_actuation()
-- put your actuation code here
end
function sysCall_sensing()
-- put your sensing code here
local result, distance, detectedPoint = sim.readProximitySensor(hFrontUS)
local msg = {}
if (distance ~= nil) then
--print(result , distance, detectedPoint, '
')
msg['data'] = distance
simROS.publish(hRosPubFrontUS, msg)
end
end
function sysCall_cleanup()
-- do some clean-up here
simROS.shutdownPublisher(hRosPubFrontUS)
end

[@jaisonjoseph9691]

Hi. Can you please help me with faking gripper action in coppeliasim through MATLAB with remote API? If not possible, is there a way to call a script in coppeliasim through MATLAB that would fake the gripping. thanks in advance

[@furien3181]

After writing rostopic list in terminal, "frontUS" does not show. What could be the problem?

[@ahmadkamalnasir6290]

The following line create the topic
hRosPubRobotUS = simROS.advertise('/robotUS', 'geometry_msgs/Vector3')
and the following lines publish the message on the topic, if they found non nil values (e.g. when you place some obstacle infront of the US)
resultfront,distancefront=sim.readProximitySensor(hFrontUS)
resultleft,distanceleft=sim.readProximitySensor(hFrontUSleft)
resultright,distanceright=sim.readProximitySensor(hFrontUSright)
local msg = {}
if(distancefront~=nil or distanceleft~=nil or distanceright~=nil) then
--print(result , distance, detectedPoint, '
')
--msg['data'] = distance
simROS.publish(hRosPubRobotUS,{x=distancefront, y=distanceleft, z=distanceright})
end

[@ashoksurabhi5731]

Hi, Can you please share the script that you use...Thanks in advance

[@FireSymphoney]

nice tutorial, but plz share the code

[@andrewmagdy5470]

could you upload the code ?

[@smailhadjbrahim3502]

Hi @andrew,
did you received the code?

[@fifield1978]

Hello, I am new to ROS. Can you share the code that you used? thanks

[@ahmadkamalnasir6290]

You may download the accompanied code from the following URL
we.tl/xijwQS9Nyz

[@guillermocastillo3711]

Hello, great demonstration!!! Please, could you upload the code again. It is not available anymore. Also, would you think VREP is a better option to work with robotic simulation than Gazebo. Thank you for your help.

[@thanhbinhdo6290]

Can you upload the code again? Thanks in advance

[@natrahmansur5212]

the code has been deleted..can you upload it back or send it through my email [e-mail]..thx in advance

[@leonardoramos2228]

hello...did u get the code? could u email me? [e-mail]

[@ravindraprasad8159]

Watch for more V-Rep tutorials: bit.ly/2LzOuae