Working with PDDL is difficult. If the PDDL domain is not well designed, or predicates or instances are missing, it is impossible to generate a plan. Plansys2 will notify you, but it is difficult to debug and solve the problem.
When it is required to generate a plan, Plansys2 generates a file with the domain, /tmp/${namespace}/domain.pddl and another with the problem /tmp/${namespace}/domain.pddl. In addition, the output of the plan solver (popf) is saved in /tmp/${namespace}/plan.pddl.
It is possible to execute the plan solver in isolation using the command:
ros2 run popf popf /tmp/${namespace}/domain.pddl /tmp/${namespace}/problem.pddlUse ros2 run popf popf -h for more help.