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tutorials:beginner:process_modules_2 [2017/09/06 13:26] – [Adding more process modules for the TurtleSim] ended code block cpotutorials:beginner:process_modules_2 [2020/09/03 10:34] (current) – [Writing a process module for the turtlesim] gkazhoya
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 **Description:** in this tutorial you will learn about CRAM process modules and write a simple one to move the turtlesim. **Description:** in this tutorial you will learn about CRAM process modules and write a simple one to move the turtlesim.
  
-**Previous Tutorial:** [[tutorials:beginner:designators|Creating action designators for the turtlesim]]\\ +**Previous Tutorial:** [[tutorials:beginner:motion_designators|Creating motion designators for the turtlesim]]\\ 
-**Next Tutorial:** [[tutorials:beginner:location_designators|Using location designators with the turtlesim]]+**Next Tutorial:** [[tutorials:beginner:assigning_actions_2|Automatically choosing a process module for a motion]]
  
 ===== Process modules: an overview ===== ===== Process modules: an overview =====
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 Once again, some new dependencies must be declared in the tutorial files you've been working on.  Once again, some new dependencies must be declared in the tutorial files you've been working on. 
  
-In your ''package.xml'' file you need to add build and runtime dependencies on ''cram_process_modules'':+In your ''package.xml'' file you need to add a dependency on ''cram_process_modules'':
  
 <code> <code>
-  <build_depend>cram_process_modules</build_depend> +  <depend>cram_process_modules</depend>
- +
-  <run_depend>cram_process_modules</run_depend>+
 </code> </code>
  
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 <code lisp> <code lisp>
-(defsystem cram-beginner-tutorial +(defsystem cram-my-beginner-tutorial 
-  :depends-on (cram-language roslisp turtlesim-msg geometry_msgs-msg cl-transforms+  :depends-on (cram-language roslisp turtlesim-msg turtlesim-srv geometry_msgs-msg cl-transforms
                              cram-designators cram-prolog                              cram-designators cram-prolog
                              cram-process-modules cram-language-designator-support)                              cram-process-modules cram-language-designator-support)
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              (:file "control-turtlesim" :depends-on ("package"))              (:file "control-turtlesim" :depends-on ("package"))
              (:file "simple-plans" :depends-on ("package" "control-turtlesim"))              (:file "simple-plans" :depends-on ("package" "control-turtlesim"))
-             (:file "action-designators" :depends-on ("package"))+             (:file "motion-designators" :depends-on ("package"))
              (:file "process-modules" :depends-on ("package"              (:file "process-modules" :depends-on ("package"
                                                    "control-turtlesim"                                                    "control-turtlesim"
                                                    "simple-plans"                                                    "simple-plans"
-                                                   "action-designators"))))))+                                                   "motion-designators"))))))
 </code> </code>
  
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 </code> </code>
  
-First, we use the ''cram-process-modules:def-process-module'' macro to define ''turtlesim-navigation'' as a process module taking one parameter (''motion-designator''). The process module then chooses which action to perform depending on the command specified in the designator: ''destructuring-bind'' maps the results from ''(reference motion-designator)'' to the variables ''command'' and ''motion'' respectively. Note that the inference rules we defined previously provide a name for the kind of motion we have (currently, all are ''drive''), and a ''turtle-motion'' object. We run an ''ecase'' on the kind of goal (currently, we only have the drive case) and use ''send-vel-cmd'' to tell the lower level to move the turtle around, given these parameters we infer from designator resolution.+First, we use the ''cram-process-modules:def-process-module'' macro to define ''turtlesim-navigation'' as a process module taking one parameter (''motion-designator''). The process module then chooses which motion to perform depending on the command specified in the designator: ''destructuring-bind'' maps the results from ''(reference motion-designator)'' to the variables ''command'' and ''motion'' respectively. Note that the inference rules we defined previously provide a name for the kind of motion we have (currently, all are ''drive''), and a ''turtle-motion'' object. We run an ''ecase'' on the kind of goal (currently, we only have the drive case) and use ''send-vel-cmd'' to tell the lower level to move the turtle around, given these parameters we infer from designator resolution.
  
 Let's try this out. Make sure you have ''roscore'' and ''turtlesim_node'' running. In a terminal tab for each, Let's try this out. Make sure you have ''roscore'' and ''turtlesim_node'' running. In a terminal tab for each,
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 <code lisp> <code lisp>
 TUT> (drive 5 2) TUT> (drive 5 2)
-[(TURTLE-PROCESS-MODULES) INFO] 1499958119.336: TurtleSim navigation invoked with motion designator `#<MOTION-DESIGNATOR ((TYPE +[(TURTLE-PROCESS-MODULES) INFO] 1562698751.679: TurtleSim navigation invoked with motion designator `#<A MOTION 
-                                                                           DRIVING) +    (TYPE DRIVING) 
-                                                                          (SPEED +    (SPEED 5) 
-                                                                           5) +    (ANGLE 2)>'.
-                                                                          (ANGLE +
-                                                                           2)) {1006979703}>'.+
 1 1
 </code> </code>
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 == Next == == Next ==
 +So far we called process modules directly. Sometimes it's better to let the system decide on its own … 
  
-Let's have a look at location designators and other ways to move the turtle, as well as have some more practice with designator resolution and process modules ... +[[tutorials:beginner:assigning_actions_2|Automatically choosing a process module for a motion]]
- +
-[[tutorials:beginner:location_designators|Using location designators with the turtlesim]]+