Update default limits for the joint limits and safety limits

README.md

@@ -110,6 +110,13 @@ Version 1.2 extends the URDF specification with extended joint limits:
 - **Deceleration limit**: The `deceleration` attribute specifies the maximum joint deceleration
 - **Jerk limit**: The `jerk` attribute specifies the maximum joint jerk (rate of change of acceleration)
 
+Version 1.2 also relaxes some requirements on the existing joint limit attributes:
+- `lower` and `upper` are optional for non-`revolute`/non-`prismatic` joints and default to `NaN` when omitted
+- for `revolute` and `prismatic` joints, both `lower` and `upper` must be provided
+- `effort` and `velocity` become optional and default to infinity when omitted
+- `effort`, `velocity`, `acceleration`, `deceleration`, and `jerk` must all be non-negative when provided
+- when both are specified, `upper` must be greater than or equal to `lower`
+
 All three attributes are optional and default to infinity (no limit). If `acceleration` is specified but `deceleration` is not, `deceleration` defaults to the acceleration value. All values must be non-negative.
 
 **Extended Joint Limits Example:**
@@ -132,6 +139,23 @@ All three attributes are optional and default to infinity (no limit). If `accele
 | `deceleration` | Maximum joint deceleration (rad/s² or m/s²) | Same as `acceleration`, or infinity if `acceleration` is not set | Must be non-negative |
 | `jerk` | Maximum joint jerk (rad/s³ or m/s³) | Infinity | Must be non-negative |
 
+#### Joint Limit Semantics By Version
+
+The parser keeps legacy behavior for older URDF versions and only applies the relaxed defaults starting in version 1.2.
+
+| Attribute | Version 1.0 / 1.1 | Version 1.2 |
+|-----------|-------------------|-------------|
+| `lower` | Optional, defaults to `0.0` when omitted | Optional for non-revolute/non-prismatic joints, defaults to `NaN` when omitted |
+| `upper` | Optional, defaults to `0.0` when omitted | Optional for non-revolute/non-prismatic joints, defaults to `NaN` when omitted |
+| `effort` | Required, parsing fails if omitted | Optional, defaults to infinity when omitted |
+| `velocity` | Required, parsing fails if omitted | Optional, defaults to infinity when omitted |
+| `acceleration` | Ignored with warning if provided | Optional, defaults to infinity when omitted |
+| `deceleration` | Ignored with warning if provided | Optional, defaults to `acceleration` if set, otherwise infinity |
+| `jerk` | Ignored with warning if provided | Optional, defaults to infinity when omitted |
+
+For all supported versions, invalid numeric values still fail parsing. In version 1.2, negative values for `effort`, `velocity`, `acceleration`, `deceleration`, and `jerk` are rejected.
+In version 1.2, `revolute` and `prismatic` joints additionally require both `lower` and `upper`, and `upper` cannot be smaller than `lower`.
+
 #### Compatibility and Parsing Behavior
 
 | Scenario | Behavior |

urdf_parser/src/joint.cpp

@@ -96,15 +96,25 @@ bool parseJointDynamics(JointDynamics &jd, tinyxml2::XMLElement* config)
 
 bool parseJointLimits(JointLimits &jl, tinyxml2::XMLElement* config,
                       const urdf_export_helpers::URDFVersion version,
-                      const std::string& joint_name)
+                      const std::string& joint_name, int joint_type)
 {
   jl.clear();
 
   // Get lower joint limit
+  bool lower_pos_limit = true;
+  bool upper_pos_limit = true;
   const char* lower_str = config->Attribute("lower");
   if (lower_str == NULL){
-    CONSOLE_BRIDGE_logDebug("urdfdom.joint_limit: joint [%s] has no lower, defaults to 0", joint_name.c_str());
-    jl.lower = 0;
+    if (version.less_than(1, 2))
+    {
+      jl.lower = 0.0;
+    }
+    else
+    {
+      jl.lower = std::numeric_limits<double>::signaling_NaN();
+    }
+    CONSOLE_BRIDGE_logInform("urdfdom.joint_limit: joint [%s] has no lower, defaults to %f", joint_name.c_str(), jl.lower);
+    lower_pos_limit = false;
   }
   else
   {
@@ -119,8 +129,16 @@ bool parseJointLimits(JointLimits &jl, tinyxml2::XMLElement* config,
   // Get upper joint limit
   const char* upper_str = config->Attribute("upper");
   if (upper_str == NULL){
-    CONSOLE_BRIDGE_logDebug("urdfdom.joint_limit: joint [%s] has no upper, defaults to 0", joint_name.c_str());
-    jl.upper = 0;
+    if (version.less_than(1, 2))
+    {
+      jl.upper = 0.0;
+    }
+    else
+    {
+      jl.upper = std::numeric_limits<double>::signaling_NaN();
+    }
+    CONSOLE_BRIDGE_logInform("urdfdom.joint_limit: joint [%s] has no upper position limit, defaults to %f", joint_name.c_str(), jl.upper);
+    upper_pos_limit = false;
   }
   else
   {
@@ -132,11 +150,37 @@ bool parseJointLimits(JointLimits &jl, tinyxml2::XMLElement* config,
     }
   }
 
+  if (version.at_least(1, 2))
+  {
+    if(!lower_pos_limit || !upper_pos_limit)
+    {
+      if (joint_type == Joint::REVOLUTE || joint_type == Joint::PRISMATIC)
+      {
+        CONSOLE_BRIDGE_logError("joint [%s]: revolute and prismatic joints must have both lower and upper position limits specified in URDF version 1.2 or later", joint_name.c_str());
+        return false;
+      }
+    }
+
+    if (lower_pos_limit && upper_pos_limit && jl.upper < jl.lower)
+    {
+      CONSOLE_BRIDGE_logError("joint [%s]: upper position limit (%f) cannot be smaller than lower position limit (%f)", joint_name.c_str(), jl.upper, jl.lower);
+      return false;
+    }
+  }
+
   // Get joint effort limit
   const char* effort_str = config->Attribute("effort");
   if (effort_str == NULL){
-    CONSOLE_BRIDGE_logError("joint [%s]: limit has no effort", joint_name.c_str());
-    return false;
+    if (version.less_than(1, 2))
+    {
+      CONSOLE_BRIDGE_logError("joint [%s]: limit has no effort", joint_name.c_str());
+      return false;
+    }
+    else
+    {
+      jl.effort = std::numeric_limits<double>::infinity();
+      CONSOLE_BRIDGE_logInform("urdfdom.joint_limit: joint [%s] has no effort limit, defaults to %f", joint_name.c_str(), jl.effort);
+    }
   }
   else
   {
@@ -156,8 +200,16 @@ bool parseJointLimits(JointLimits &jl, tinyxml2::XMLElement* config,
   // Get joint velocity limit
   const char* velocity_str = config->Attribute("velocity");
   if (velocity_str == NULL){
-    CONSOLE_BRIDGE_logError("joint [%s]: limit has no velocity", joint_name.c_str());
-    return false;
+    if (version.less_than(1, 2))
+    {
+      CONSOLE_BRIDGE_logError("joint [%s]: limit has no velocity", joint_name.c_str());
+      return false;
+    }
+    else
+    {
+      jl.velocity = std::numeric_limits<double>::infinity();
+      CONSOLE_BRIDGE_logInform("urdfdom.joint_limit: joint [%s] has no velocity limit, defaults to %f", joint_name.c_str(), jl.velocity);
+    }
   }
   else
   {
@@ -543,7 +595,7 @@ bool parseJoint(Joint &joint, tinyxml2::XMLElement* config,
   if (limit_xml)
   {
     joint.limits.reset(new JointLimits());
-    if (!parseJointLimits(*joint.limits, limit_xml, version, joint.name))
+    if (!parseJointLimits(*joint.limits, limit_xml, version, joint.name, joint.type))
     {
       CONSOLE_BRIDGE_logError("Could not parse limit element for joint [%s]", joint.name.c_str());
       joint.limits.reset();