Improve error message when calling iris clique cover without joint li…

…mits (RobotLocomotion#21207)

Previously the error was an unhelpful throw from HPolyhedron saying
some set was unbounded (which is confusing for a method whose goal is
to use complex logic to assemble new hpolyhedron). We can fail-fast on
this one and give a much more clear/specific error message.

planning/iris/BUILD.bazel

@@ -40,7 +40,10 @@ drake_cc_library(
 drake_cc_googletest(
     name = "iris_from_clique_cover_test",
     timeout = "moderate",
-    data = ["//multibody/parsing:test_models"],
+    data = [
+        "//examples/pendulum:models",
+        "//multibody/parsing:test_models",
+    ],
     # Running with multiple threads is an essential part of our test coverage.
     num_threads = 4,
     shard_count = 4,
@@ -55,6 +58,7 @@ drake_cc_googletest(
     ],
     deps = [
         ":iris_from_clique_cover",
+        "//common/test_utilities:expect_throws_message",
         "//common/test_utilities:maybe_pause_for_user",
         "//geometry/test_utilities:meshcat_environment",
         "//multibody/parsing:parser",

planning/iris/iris_from_clique_cover.cc

@@ -330,6 +330,13 @@ void IrisInConfigurationSpaceFromCliqueCover(
   DRAKE_THROW_UNLESS(options.coverage_termination_threshold > 0);
   DRAKE_THROW_UNLESS(options.iteration_limit > 0);
 
+  // Note: Even though the iris_options.bounding_region may be provided,
+  // IrisInConfigurationSpace (currently) requires finite joint limits.
+  DRAKE_THROW_UNLESS(
+      checker.plant().GetPositionLowerLimits().array().isFinite().all());
+  DRAKE_THROW_UNLESS(
+      checker.plant().GetPositionUpperLimits().array().isFinite().all());
+
   const HPolyhedron domain = options.iris_options.bounding_region.value_or(
       HPolyhedron::MakeBox(checker.plant().GetPositionLowerLimits(),
                            checker.plant().GetPositionUpperLimits()));

planning/iris/test/iris_from_clique_cover_test.cc

@@ -4,6 +4,7 @@
 
 #include "drake/common/find_resource.h"
 #include "drake/common/ssize.h"
+#include "drake/common/test_utilities/expect_throws_message.h"
 #include "drake/common/test_utilities/maybe_pause_for_user.h"
 #include "drake/geometry/optimization/hpolyhedron.h"
 #include "drake/geometry/optimization/hyperrectangle.h"
@@ -159,6 +160,30 @@ GTEST_TEST(IrisInConfigurationSpaceFromCliqueCover, BoxConfigurationSpaceTest) {
   EXPECT_EQ(vpoly.CalcVolume(), 16.0);
 }
 
+// Plants that don't have joint limits get a reasonable error message.
+GTEST_TEST(IrisInConfigurationSpaceFromCliqueCover, NoJointLimits) {
+  CollisionCheckerParams params;
+
+  RobotDiagramBuilder<double> builder(0.0);
+  params.robot_model_instances = builder.parser().AddModelsFromUrl(
+      "package://drake/examples/pendulum/Pendulum.urdf");
+  params.edge_step_size = 0.01;
+
+  params.model = builder.Build();
+  auto checker =
+      std::make_unique<SceneGraphCollisionChecker>(std::move(params));
+
+  IrisFromCliqueCoverOptions options;
+  std::vector<HPolyhedron> sets;
+
+  RandomGenerator generator(0);
+
+  DRAKE_EXPECT_THROWS_MESSAGE(
+      IrisInConfigurationSpaceFromCliqueCover(*checker, options, &generator,
+                                              &sets, nullptr),
+      ".*.GetPositionLowerLimits.*isFinite.* failed.");
+}
+
 /* A movable sphere with fixed boxes in all corners.
 ┌───────────────┐
 │┌────┐   ┌────┐│