TIGERBOT 2 REJUVENATION

PREVIOUS STATE OF PROJECT Tigerbot 2 Previously used Custom Computing solutions Implicit to these solutions were Custom Proprietary hardware (RowBoard) Custom Libraries Deprecated version of ROS No Visualizations No Path or Trajectory planning

Goals Of Project Convert Tigerbot To Current Ros Version Provide a ROS package that Can be Used Multiple Linux Platforms Single Board Computer Running Linux Laptop or CPU Running Linux Adding Trajectory And Path Planning through the use of Moveit! and the use of OMPL (Open Motion Planning Library) Implement Balancing And WAlking Algorithm

Embedded Controller Changed / Added Servo Control Migrated From SSC32 Servo Controller To the Teensy 3.1 Arm Cortex M4 Provided the Ability to Publish directly to ROS topics More control and options for controller configuration and implementation.

Primary Communication Communication Over USB for High Bandwidth Trajectory position Commands Commands can originate from any linux machine running ROS Any Single Board Computer Laptop / CPU

Xtion IMU IMU Laptop Or Odroid USB BUS Tigerbot Teensy Left Side Point Cloud Depth Spectrum (USB) IMU IMU I2C Direct connect to Main CPU I2C Direct connect to Main CPU Laptop Or Odroid USB BUS Tigerbot Teensy Left Side Tigerbot Teensy Right Side Sensors Sensors Servos Servos

Leg Joint Group Sensor Modules Joint Vals Pose Twist *TF is a Transformation Message that updates the Robot Pose for Motion Planning Plugins Joint Vals Pose Twist Linear and Angular Effort Torque Motion/Trajectory Planner TF* Robot State CPU RosSerial (USB) Joint Group message (6 Values) Leg Joint Group Teensy Position Hip Rotation Servo Leg Servo Feedback Position Hip lift Servo 6 PWM Control Servo Feedback Position Hip Side Lift Servo Servo Feedback Servo FeedBack Callback Position Knee Servo Servo Feedback Position Ankle Lift Servo Sensors Interface Servo Feedback Position Ankle Side Lift Servo Servo Feedback Sensor Data from Interfaces Sensor Modules

User Interface (RViz, MoveIt, etc.) Scene Information, Robot State, Motion Request Motion Response, Collision Avoidance URDF, Config Joint States, Transformation Matrix Robot Model ROS Interface Load/Unload Controllers Controller Manager Controller Feed commands to hardware interface from ROS interface Hardware Resource Interface Communicate with the hardware Hardware Interface readHW() writeHW() readSim() writeSim() Hardware Gazebo

Hardware Abstraction Layer Isolates Embedded System Software - ROS Hardware Resource Interface Layer Hardware Abstraction Layer Isolates Embedded System Embedded side can be changed without affecting high level stack Hardware Interface can be be emulated by Gazebo Simulator Real Robot RobotHW Teensy Hardware Interface L_Arm_Command L_Arm R_Arm L_Leg R_Leg L_Arm R_Arm L_Leg R_Leg L_Arm_State l_arm (URDF) left_shoulder_lift_joint left_shoulder_side_joint left_shoulder_rot_joint left_elbow_joint

Description Of Tigerbot describes joint relations XML snips from URDF Torso (Base Link) Parent Child Relationships <joint name="right_shoulder_side_joint" type="revolute"> <parent link="torso" /> <child link="right_shoulder_side_link" /> </joint> Description Of Tigerbot describes joint relations creates a joint link chain for Inverse kinematic solvers. Allows For accurate representation of Robot in Software Joint Names used to register joints with ros controllers Right Shoulder Joint Right Shoulder side Link <joint name="right_shoulder_rot_joint" type="revolute"> <parent link="right_shoulder_side_link" /> <child link="right_shoulder_rot_link" /> </joint> Right Shoulder rot Joint Right Shoulder rot Link <joint name="right_elbow_joint" type="revolute"> <parent link="right_shoulder_rot_link" /> <child link="right_elbow_link" /> </joint> Right Elbow Joint Right Elbow link

Frame Transformations Teknic HLS (High level Status bit) Gazebo Simulation URDF (Unified Robot Description File) Parameter Server (contains robot description) Joint_states (feedback) Robot State Publisher TF (Transformation Frame package) Visualization (Rviz)

CPU IMU Teensy Publish Subscribe Imu Topic <sensor_msgs/Imu> Header Sequence ID Timestamp Frame ID Accel / Gyro Info Orientation(X Y Z W) Angular Velocity(X Y Z) Linear Accelerations Joint[n]_command <trajectory_msgs/JointTrajectory> Header Sequence ID Timestamp Frame ID Joint names Joint Trajectory Points Positions Velocities Accelerations Effort Duration CPU IMU Teensy Joint[n]_state <sensor_msgs/JointState> Header Sequence ID Timestamp Frame ID Name Position Velocity Effort Publish Subscribe

Using joint trajectory controllers for motion Problems Encountered Joint Limits Not Responding Correctly Coordinate Frames Were Not placed with Care Initially. Attempts to re-export model did not go as planned Moving Forward Using joint trajectory controllers for motion Moveit seems to cause more Problems than it solves as of this point (for motion planning)