Create a demo for one motor gripper grasp.

6 files changed, 528 insertions, 7 deletions

diff --git a/data/gripper/wsg50_one_motor_gripper.sdf b/data/gripper/wsg50_one_motor_gripper.sdf
new file mode 100644
index 000000000..46516fe1b
--- /dev/null
+++ b/data/gripper/wsg50_one_motor_gripper.sdf
@@ -0,0 +1,388 @@
+<?xml version="1.0" ?>
+<sdf version='1.6'>
+  <world name='default'>
+  <model name='wsg50_with_gripper'>
+    <pose frame=''>0 0 0.26 3.14 0 0</pose>
+	
+    <link name='world'>
+	</link>
+  
+    <joint name='base_joint' type='prismatic'>
+      <parent>world</parent>
+      <child>base_link</child>
+      <axis>
+        <xyz>0 0 1</xyz>
+        <limit>
+          <lower>-0.5</lower>
+          <upper>10</upper>
+          <effort>1</effort>
+          <velocity>1</velocity>
+        </limit>
+        <dynamics>
+          <damping>0</damping>
+          <friction>0</friction>
+          <spring_reference>0</spring_reference>
+          <spring_stiffness>0</spring_stiffness>
+        </dynamics>
+      </axis>
+    </joint>
+
+    <link name='base_link'>
+      <pose frame=''>0 0 0 0 0 0</pose>
+      <inertial>
+        <pose frame=''>0 0 0 0 0 0</pose>
+        <mass>1.2</mass>
+        <inertia>
+          <ixx>1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>1</iyy>
+          <iyz>0</iyz>
+          <izz>1</izz>
+        </inertia>
+      </inertial>
+	  
+      <visual name='base_link_visual'>
+        <pose frame=''>0 0 0 0 -0 0</pose>
+        <geometry>
+          <mesh>
+            <scale>1 1 1</scale>
+            <uri>meshes/WSG50_110.stl</uri>
+          </mesh>
+        </geometry>
+        <material>
+
+        </material>
+      </visual>
+	  
+    </link>
+	
+    <link name='motor'>
+      <pose frame=''>0 0 0.03 0 0 0</pose>
+      <inertial>
+        <pose frame=''>0 0 0 0 0 0</pose>
+        <mass>0.1</mass>
+        <inertia>
+          <ixx>0.1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>0.1</iyy>
+          <iyz>0</iyz>
+          <izz>0.1</izz>
+        </inertia>
+      </inertial>
+      <visual name='motor_visual'>
+        <pose frame=''>0 0 0.01 0 0 0</pose>
+        <geometry>
+		  <box>
+            <size>0.02 0.02 0.02 </size>
+          </box>
+        </geometry>
+      </visual>
+    </link>
+	
+    <joint name='base_joint_motor' type='prismatic'>
+      <child>motor</child>
+      <parent>base_link</parent>
+      <axis>
+        <xyz>0 0 1</xyz>
+        <limit>
+          <lower>-0.047</lower>
+          <upper>0.001</upper>
+          <effort>10.0</effort>
+          <velocity>10.0</velocity>
+        </limit>
+        <dynamics>
+          <damping>0</damping>
+          <friction>0</friction>
+          <spring_reference>0</spring_reference>
+          <spring_stiffness>0</spring_stiffness>
+        </dynamics>
+      </axis>
+    </joint>
+	
+    <link name='left_hinge'>
+      <pose frame=''>0 0 0.04 0 0 0</pose>
+      <inertial>
+        <pose frame=''>0 0 0.035 0 0 0</pose>
+        <mass>0.1</mass>
+        <inertia>
+          <ixx>0.1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>0.1</iyy>
+          <iyz>0</iyz>
+          <izz>0.1</izz>
+        </inertia>
+      </inertial>
+      <visual name='motor_visual'>
+        <pose frame=''>-0.03 0 0.01 0 -1.2 0</pose>
+        <geometry>
+		  <box>
+            <size>0.02 0.02 0.07 </size>
+          </box>
+        </geometry>
+      </visual>
+    </link>
+	
+    <joint name='motor_left_hinge_joint' type='revolute'>
+      <child>left_hinge</child>
+      <parent>motor</parent>
+      <axis>
+        <xyz>0 1 0</xyz>
+        <limit>
+          <lower>-20.0</lower>
+          <upper>20.0</upper>
+          <effort>10</effort>
+          <velocity>10</velocity>
+        </limit>
+        <dynamics>
+          <damping>0</damping>
+          <friction>0</friction>
+          <spring_reference>0</spring_reference>
+          <spring_stiffness>0</spring_stiffness>
+        </dynamics>
+        <use_parent_model_frame>0</use_parent_model_frame>
+      </axis>
+    </joint>
+	
+    <link name='right_hinge'>
+      <pose frame=''>0 0 0.04 0 0 0</pose>
+      <inertial>
+        <pose frame=''>0 0 0.035 0 0 0</pose>
+        <mass>0.1</mass>
+        <inertia>
+          <ixx>0.1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>0.1</iyy>
+          <iyz>0</iyz>
+          <izz>0.1</izz>
+        </inertia>
+      </inertial>
+      <visual name='motor_visual'>
+        <pose frame=''>0.03 0 0.01 0 1.2 0</pose>
+        <geometry>
+		  <box>
+            <size>0.02 0.02 0.07 </size>
+          </box>
+        </geometry>
+      </visual>
+    </link>
+	
+    <joint name='motor_right_hinge_joint' type='revolute'>
+      <child>right_hinge</child>
+      <parent>motor</parent>
+      <axis>
+        <xyz>0 1 0</xyz>
+        <limit>
+          <lower>-20.0</lower>
+          <upper>20.0</upper>
+          <effort>10</effort>
+          <velocity>10</velocity>
+        </limit>
+        <dynamics>
+          <damping>0</damping>
+          <friction>0</friction>
+          <spring_reference>0</spring_reference>
+          <spring_stiffness>0</spring_stiffness>
+        </dynamics>
+        <use_parent_model_frame>0</use_parent_model_frame>
+      </axis>
+    </joint>
+
+    <link name='gripper_left'>
+      <pose frame=''>-0.055 0 0.06 0 -0 0</pose>
+      <inertial>
+        <pose frame=''>0 0 0.0115 0 -0 0</pose>
+        <mass>0.2</mass>
+        <inertia>
+          <ixx>0.1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>0.1</iyy>
+          <iyz>0</iyz>
+          <izz>0.1</izz>
+        </inertia>
+      </inertial>
+	  
+      <visual name='gripper_left_visual'>
+        <pose frame=''>0 0 -0.06 0 0 0</pose>
+        <geometry>
+          <mesh>
+            <scale>0.001 0.001 0.001</scale>
+            <uri>meshes/GUIDE_WSG50_110.stl</uri>
+          </mesh>
+        </geometry>
+      </visual>
+      <visual name='gripper_left_fixed_joint_lump__finger_left_visual_1'>
+        <pose frame=''>0 0 -0.037 0 0 0</pose>
+        <geometry>
+          <mesh>
+            <scale>0.001 0.001 0.001</scale>
+            <uri>meshes/WSG-FMF.stl</uri>
+          </mesh>
+        </geometry>
+      </visual>
+
+    </link>
+	
+    <joint name='gripper_left_hinge_joint' type='revolute'>
+      <child>gripper_left</child>
+      <parent>left_hinge</parent>
+      <axis>
+        <xyz>0 1 0</xyz>
+        <limit>
+          <lower>-1.0</lower>
+          <upper>1.0</upper>
+          <effort>10</effort>
+          <velocity>10</velocity>
+        </limit>
+        <dynamics>
+          <damping>0.01</damping>
+          <friction>0</friction>
+          <spring_reference>0</spring_reference>
+          <spring_stiffness>0</spring_stiffness>
+        </dynamics>
+        <use_parent_model_frame>0</use_parent_model_frame>
+      </axis>
+    </joint>
+	
+    <link name='gripper_right'>
+      <pose frame=''>0.055 0 0.06 0 0 3.14159</pose>
+      <inertial>
+        <pose frame=''>0 0 0.0115 0 -0 0</pose>
+        <mass>0.2</mass>
+        <inertia>
+          <ixx>0.1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>0.1</iyy>
+          <iyz>0</iyz>
+          <izz>0.1</izz>
+        </inertia>
+      </inertial>
+	  
+      <visual name='gripper_right_visual'>
+        <pose frame=''>0 0 -0.06 0 0 0</pose>
+        <geometry>
+          <mesh>
+            <scale>0.001 0.001 0.001</scale>
+            <uri>meshes/GUIDE_WSG50_110.stl</uri>
+          </mesh>
+        </geometry>
+      </visual>
+      <visual name='gripper_right_fixed_joint_lump__finger_right_visual_1'>
+        <pose frame=''>0 0 -0.037 0 0 0</pose>
+        <geometry>
+          <mesh>
+            <scale>0.001 0.001 0.001</scale>
+            <uri>meshes/WSG-FMF.stl</uri>
+          </mesh>
+        </geometry>
+      </visual>
+    </link>
+	
+    <joint name='gripper_right_hinge_joint' type='revolute'>
+      <child>gripper_right</child>
+      <parent>right_hinge</parent>
+      <axis>
+        <xyz>0 1 0</xyz>
+        <limit>
+          <lower>-1.0</lower>
+          <upper>1.0</upper>
+          <effort>10</effort>
+          <velocity>10</velocity>
+        </limit>
+        <dynamics>
+          <damping>0.01</damping>
+          <friction>0</friction>
+          <spring_reference>0</spring_reference>
+          <spring_stiffness>0</spring_stiffness>
+        </dynamics>
+        <use_parent_model_frame>0</use_parent_model_frame>
+      </axis>
+    </joint>
+    
+    <link name='finger_right'>
+      <pose frame=''>0.062 0 0.145 0 0 1.5708</pose>
+      <inertial>
+        <mass>0.2</mass>
+        <inertia>
+          <ixx>0.1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>0.1</iyy>
+          <iyz>0</iyz>
+          <izz>0.1</izz>
+        </inertia>
+      </inertial>
+	  
+        <collision name='finger_right_collision'>
+  	<pose frame=''>0 0 0.042 0 0 0 </pose>
+  	<geometry>        
+         <box>
+                <size>0.02 0.02 0.15 </size>
+              </box>
+
+          </geometry>
+        </collision>
+	  
+      <visual name='finger_right_visual'>
+        <pose frame=''>0 0 0 0 0 0 </pose>
+        <geometry>
+          <mesh>
+            <scale>1 1 1 </scale>
+            <uri>meshes/l_gripper_tip_scaled.stl</uri>
+          </mesh>
+        </geometry>
+      </visual>
+    </link>
+	
+    <joint name='gripper_finger_right' type='fixed'>
+      <parent>gripper_right</parent>
+      <child>finger_right</child>
+    </joint>
+    
+    <link name='finger_left'>
+      <pose frame=''>-0.062 0 0.145 0 0 4.71239</pose>
+      <inertial>
+        <mass>0.2</mass>
+        <inertia>
+          <ixx>0.1</ixx>
+          <ixy>0</ixy>
+          <ixz>0</ixz>
+          <iyy>0.1</iyy>
+          <iyz>0</iyz>
+          <izz>0.1</izz>
+        </inertia>
+      </inertial>
+	  
+      <collision name='finger_left_collision'>
+        <pose frame=''>0 0 0.042 0 0 0 </pose>
+        <geometry>
+               <box>
+              <size>0.02 0.02 0.15 </size>
+            </box>
+
+        </geometry>
+      </collision>
+	  
+      <visual name='finger_left_visual'>
+        <pose frame=''>0 0 0 0 0 0 </pose>
+        <geometry>
+          <mesh>
+            <scale>1 1 1 </scale>
+            <uri>meshes/l_gripper_tip_scaled.stl</uri>
+          </mesh>
+        </geometry>
+      </visual>
+    </link>
+	
+    <joint name='gripper_finger_left' type='fixed'>
+      <parent>gripper_left</parent>
+      <child>finger_left</child>
+    </joint>
+  </model>
+</world>
+</sdf>
diff --git a/examples/ExampleBrowser/ExampleEntries.cpp b/examples/ExampleBrowser/ExampleEntries.cpp
index aa7217502..0608f0bd1 100644
--- a/examples/ExampleBrowser/ExampleEntries.cpp
+++ b/examples/ExampleBrowser/ExampleEntries.cpp
@@ -266,7 +266,7 @@ static ExampleEntry gDefaultExamples[]=
     ExampleEntry(1,"Rolling friction","Experiment on multibody rolling friction", R2D2GraspExampleCreateFunc,eROBOTIC_LEARN_ROLLING_FRICTION),
     ExampleEntry(1,"Gripper Grasp","Grasp experiment with a gripper to improve contact model", GripperGraspExampleCreateFunc,eGRIPPER_GRASP),
     ExampleEntry(1,"Two Point Grasp","Grasp experiment with two point contact to test rolling friction", GripperGraspExampleCreateFunc, eTWO_POINT_GRASP),
-	
+	ExampleEntry(1,"One Motor Gripper Grasp","Grasp experiment with a gripper with one motor to test slider constraint for closed loop structure", GripperGraspExampleCreateFunc, eONE_MOTOR_GRASP),
 
 
 #ifdef ENABLE_LUA
diff --git a/examples/RoboticsLearning/GripperGraspExample.cpp b/examples/RoboticsLearning/GripperGraspExample.cpp
index 9a7ab8e7b..7aa2f2571 100644
--- a/examples/RoboticsLearning/GripperGraspExample.cpp
+++ b/examples/RoboticsLearning/GripperGraspExample.cpp
@@ -10,6 +10,7 @@
 #include "../SharedMemory/PhysicsServerSharedMemory.h"
 #include "../SharedMemory/PhysicsClientC_API.h"
 #include "../CommonInterfaces/CommonParameterInterface.h"
+#include "../SharedMemory/SharedMemoryPublic.h"
 #include <string>
 
 #include "b3RobotSimAPI.h"
@@ -213,6 +214,120 @@ public:
             m_robotSim.setGravity(b3MakeVector3(0,0,-10));
             m_robotSim.setNumSimulationSubSteps(4);
         }
+        
+        if ((m_options & eONE_MOTOR_GRASP)!=0)
+        {
+            
+            {
+                SliderParams slider("Vertical velocity",&sGripperVerticalVelocity);
+                slider.m_minVal=-2;
+                slider.m_maxVal=2;
+                m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
+            }
+            
+            {
+                SliderParams slider("Closing velocity",&sGripperClosingTargetVelocity
+                                    );
+                slider.m_minVal=-1;
+                slider.m_maxVal=1;
+                m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
+            }
+            {
+                b3RobotSimLoadFileArgs args("");
+                b3RobotSimLoadFileResults results;
+                args.m_fileName = "cube_small.urdf";
+                args.m_startPosition.setValue(0, 0, .107);
+                args.m_startOrientation.setEulerZYX(0, 0, 0);
+                args.m_useMultiBody = true;
+                m_robotSim.loadFile(args, results);
+            }
+            
+            {
+                b3RobotSimLoadFileArgs args("");
+                args.m_fileName = "gripper/wsg50_one_motor_gripper.sdf";
+                args.m_fileType = B3_SDF_FILE;
+                args.m_useMultiBody = true;
+                b3RobotSimLoadFileResults results;
+                
+                if (m_robotSim.loadFile(args, results) && results.m_uniqueObjectIds.size()==1)
+                {
+                    
+                    m_gripperIndex = results.m_uniqueObjectIds[0];
+                    int numJoints = m_robotSim.getNumJoints(m_gripperIndex);
+                    b3Printf("numJoints = %d",numJoints);
+                    
+                    for (int i=0;i<numJoints;i++)
+                    {
+                        b3JointInfo jointInfo;
+                        m_robotSim.getJointInfo(m_gripperIndex,i,&jointInfo);
+                        b3Printf("joint[%d].m_jointName=%s",i,jointInfo.m_jointName);
+                    }
+                    
+                    for (int i=0;i<8;i++)
+                    {
+                        b3JointMotorArgs controlArgs(CONTROL_MODE_VELOCITY);
+                        controlArgs.m_maxTorqueValue = 0.0;
+                        m_robotSim.setJointMotorControl(m_gripperIndex,i,controlArgs);
+                    }
+
+                }
+            }
+            
+            if (1)
+            {
+                b3RobotSimLoadFileArgs args("");
+                args.m_fileName = "plane.urdf";
+                args.m_startPosition.setValue(0,0,0);
+                args.m_startOrientation.setEulerZYX(0,0,0);
+                args.m_forceOverrideFixedBase = true;
+                args.m_useMultiBody = true;
+                b3RobotSimLoadFileResults results;
+                m_robotSim.loadFile(args,results);
+                
+            }
+            m_robotSim.setGravity(b3MakeVector3(0,0,-10));
+            
+            b3JointInfo sliderJoint1;
+            sliderJoint1.m_parentFrame[0] = 0;
+            sliderJoint1.m_parentFrame[1] = 0;
+            sliderJoint1.m_parentFrame[2] = 0.06;
+            sliderJoint1.m_parentFrame[3] = 0;
+            sliderJoint1.m_parentFrame[4] = 0;
+            sliderJoint1.m_parentFrame[5] = 0;
+            sliderJoint1.m_parentFrame[6] = 1.0;
+            sliderJoint1.m_childFrame[0] = 0;
+            sliderJoint1.m_childFrame[1] = 0;
+            sliderJoint1.m_childFrame[2] = 0;
+            sliderJoint1.m_childFrame[3] = 0;
+            sliderJoint1.m_childFrame[4] = 0;
+            sliderJoint1.m_childFrame[5] = 0;
+            sliderJoint1.m_childFrame[6] = 1.0;
+            sliderJoint1.m_jointAxis[0] = 1.0;
+            sliderJoint1.m_jointAxis[1] = 0.0;
+            sliderJoint1.m_jointAxis[2] = 0.0;
+            sliderJoint1.m_jointType = ePrismaticType;
+            b3JointInfo sliderJoint2;
+            sliderJoint2.m_parentFrame[0] = 0;
+            sliderJoint2.m_parentFrame[1] = 0;
+            sliderJoint2.m_parentFrame[2] = 0.06;
+            sliderJoint2.m_parentFrame[3] = 0;
+            sliderJoint2.m_parentFrame[4] = 0;
+            sliderJoint2.m_parentFrame[5] = 0;
+            sliderJoint2.m_parentFrame[6] = 1.0;
+            sliderJoint2.m_childFrame[0] = 0;
+            sliderJoint2.m_childFrame[1] = 0;
+            sliderJoint2.m_childFrame[2] = 0;
+            sliderJoint2.m_childFrame[3] = 0;
+            sliderJoint2.m_childFrame[4] = 0;
+            sliderJoint2.m_childFrame[5] = 1.0;
+            sliderJoint2.m_childFrame[6] = 0;
+            sliderJoint2.m_jointAxis[0] = 1.0;
+            sliderJoint2.m_jointAxis[1] = 0.0;
+            sliderJoint2.m_jointAxis[2] = 0.0;
+            sliderJoint2.m_jointType = ePrismaticType;
+            m_robotSim.createJoint(1, 0, 1, 3, &sliderJoint1);
+            m_robotSim.createJoint(1, 0, 1, 6, &sliderJoint2);
+        }
 		
     }
     virtual void    exitPhysics()
@@ -241,6 +356,22 @@ public:
             }
         }
         
+        if ((m_options & eONE_MOTOR_GRASP)!=0)
+        {
+            int fingerJointIndices[2]={0,1};
+            double fingerTargetVelocities[2]={sGripperVerticalVelocity,sGripperClosingTargetVelocity
+            };
+            double maxTorqueValues[2]={50.0,50.0};
+            for (int i=0;i<2;i++)
+            {
+                b3JointMotorArgs controlArgs(CONTROL_MODE_VELOCITY);
+                controlArgs.m_targetVelocity = fingerTargetVelocities[i];
+                controlArgs.m_maxTorqueValue = maxTorqueValues[i];
+                controlArgs.m_kd = 1.;
+                m_robotSim.setJointMotorControl(m_gripperIndex,fingerJointIndices[i],controlArgs);
+            }
+        }
+        
 		m_robotSim.stepSimulation();
     }
     virtual void	renderScene()
diff --git a/examples/RoboticsLearning/GripperGraspExample.h b/examples/RoboticsLearning/GripperGraspExample.h
index 94835878c..37177823f 100644
--- a/examples/RoboticsLearning/GripperGraspExample.h
+++ b/examples/RoboticsLearning/GripperGraspExample.h
@@ -20,6 +20,7 @@ enum GripperGraspExampleOptions
 {
     eGRIPPER_GRASP=1,
     eTWO_POINT_GRASP=2,
+    eONE_MOTOR_GRASP=4,
 };
 
 class CommonExampleInterface*    GripperGraspExampleCreateFunc(struct CommonExampleOptions& options);
diff --git a/examples/SharedMemory/PhysicsServerCommandProcessor.cpp b/examples/SharedMemory/PhysicsServerCommandProcessor.cpp
index 85839e322..9217ac88c 100644
--- a/examples/SharedMemory/PhysicsServerCommandProcessor.cpp
+++ b/examples/SharedMemory/PhysicsServerCommandProcessor.cpp
@@ -2502,34 +2502,34 @@ bool PhysicsServerCommandProcessor::processCommand(const struct SharedMemoryComm
                             btMatrix3x3 frameInParent(btQuaternion(clientCmd.m_createJointArguments.m_parentFrame[3], clientCmd.m_createJointArguments.m_parentFrame[4], clientCmd.m_createJointArguments.m_parentFrame[5], clientCmd.m_createJointArguments.m_parentFrame[6]));
                             btMatrix3x3 frameInChild(btQuaternion(clientCmd.m_createJointArguments.m_childFrame[3], clientCmd.m_createJointArguments.m_childFrame[4], clientCmd.m_createJointArguments.m_childFrame[5], clientCmd.m_createJointArguments.m_childFrame[6]));
                             btVector3 jointAxis(clientCmd.m_createJointArguments.m_jointAxis[0], clientCmd.m_createJointArguments.m_jointAxis[1], clientCmd.m_createJointArguments.m_jointAxis[2]);
-                            if (clientCmd.m_createJointArguments.m_jointType == btMultibodyLink::eFixed)
+                            if (clientCmd.m_createJointArguments.m_jointType == eFixedType)
                             {
                                 if (childBody->m_multiBody)
                                 {
                                     btMultiBodyFixedConstraint* multibodyFixed = new btMultiBodyFixedConstraint(parentBody->m_multiBody,clientCmd.m_createJointArguments.m_parentJointIndex,childBody->m_multiBody,clientCmd.m_createJointArguments.m_childJointIndex,pivotInParent,pivotInChild,frameInParent,frameInChild);
-                                    multibodyFixed->setMaxAppliedImpulse(2.0);
+                                    multibodyFixed->setMaxAppliedImpulse(500.0);
                                     m_data->m_dynamicsWorld->addMultiBodyConstraint(multibodyFixed);
                                 }
                                 else
                                 {
                                     btMultiBodyFixedConstraint* rigidbodyFixed = new btMultiBodyFixedConstraint(parentBody->m_multiBody,clientCmd.m_createJointArguments.m_parentJointIndex,childBody->m_rigidBody,pivotInParent,pivotInChild,frameInParent,frameInChild);
-                                    rigidbodyFixed->setMaxAppliedImpulse(2.0);
+                                    rigidbodyFixed->setMaxAppliedImpulse(500.0);
                                     btMultiBodyDynamicsWorld* world = (btMultiBodyDynamicsWorld*) m_data->m_dynamicsWorld;
                                     world->addMultiBodyConstraint(rigidbodyFixed);
                                 }
                             }
-                            else if (clientCmd.m_createJointArguments.m_jointType == btMultibodyLink::ePrismatic)
+                            else if (clientCmd.m_createJointArguments.m_jointType == ePrismaticType)
                             {
                                 if (childBody->m_multiBody)
                                 {
                                     btMultiBodySliderConstraint* multibodySlider = new btMultiBodySliderConstraint(parentBody->m_multiBody,clientCmd.m_createJointArguments.m_parentJointIndex,childBody->m_multiBody,clientCmd.m_createJointArguments.m_childJointIndex,pivotInParent,pivotInChild,frameInParent,frameInChild,jointAxis);
-                                    multibodySlider->setMaxAppliedImpulse(2.0);
+                                    multibodySlider->setMaxAppliedImpulse(500.0);
                                     m_data->m_dynamicsWorld->addMultiBodyConstraint(multibodySlider);
                                 }
                                 else
                                 {
                                     btMultiBodySliderConstraint* rigidbodySlider = new btMultiBodySliderConstraint(parentBody->m_multiBody,clientCmd.m_createJointArguments.m_parentJointIndex,childBody->m_rigidBody,pivotInParent,pivotInChild,frameInParent,frameInChild,jointAxis);
-                                    rigidbodySlider->setMaxAppliedImpulse(2.0);
+                                    rigidbodySlider->setMaxAppliedImpulse(500.0);
                                     btMultiBodyDynamicsWorld* world = (btMultiBodyDynamicsWorld*) m_data->m_dynamicsWorld;
                                     world->addMultiBodyConstraint(rigidbodySlider);
                                 }
diff --git a/examples/SharedMemory/SharedMemoryPublic.h b/examples/SharedMemory/SharedMemoryPublic.h
index b9a5c9eb5..dbb4dcd19 100644
--- a/examples/SharedMemory/SharedMemoryPublic.h
+++ b/examples/SharedMemory/SharedMemoryPublic.h
@@ -98,6 +98,7 @@ enum
 enum JointType {
     eRevoluteType = 0,
     ePrismaticType = 1,
+    eFixedType = 2,
 };
 
 struct b3JointInfo