Toolset query child post meta

        $child_posts = toolset_get_related_posts( $post_id, 'parent-child-relationship-slug', array( 'query_by_role' => 'parent', 'return' => 'post_object'));
        foreach ($child_posts as $child_post) {
            $custom_title = types_render_field('title', array("id"=> "$child_post->ID"));
        }