edit launch to work with clock, pepper meshes

crowdbotsim/launch/unity_sim.launch

@@ -14,6 +14,7 @@ limitations under the License.
 -->
 
 <launch>
+	<param name ="/use_sim_time" value="true"/>
 
 	<include file="$(find rosbridge_server)/launch/rosbridge_websocket.launch">
 		<param name="port" value="9090"/>